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  • 1.
    Abbasi, M.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Backstrom, J.
    Mid Sweden Univ, FSCN Mat Phys, Dept Nat Sci, SE-85170 Sundsvall, Sweden..
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Fabrication of Spin-Coated Ti/TiHx/Ni-Sb-SnO2 Electrode: Stability and Electrocatalytic Activity2018In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, no 9, p. H568-H574Article in journal (Refereed)
    Abstract [en]

    A novel three-layer anode having the composition Ti/TiHx/Ni-Sb-SnO2 (Ti/TiHx/NATO) was successfully prepared by a spin-coating and pyrolysis process aiming at a long service lifetime and good electrocatalytic properties for ozone formation. The TiHx as an interlayer was produced by electrochemical cathodic reduction of a coated layer of the TiOx on the titanium substrate. Spin coating and thermal decomposition were used to deposit the Sn-Sb-Ni precursor on the surface of the prepared Ti/TiHx electrode. Cyclic and linear scanning voltammetry, Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to reveal the electrode performance and morphology. Results show that the onset potential for the oxygen evolution reaction (OER) of Ti/TiHx /NATO is higher than for Ti/NATO. They also indicate that the service lifetime of the Ti/TiHx/NATO is twice as long as the Ti/NATO at a current density of 50 mA.cm(-2) at room temperature. Electrochemical ozone generation and degradation of the methylene blue were investigated to confirm selectivity and activity of the electrodes. After 5 min electrolysis, a current efficiency for ozone generation of 56% was obtained the electrode with TiHx while 38% was obtained on Ti/NATO under same conditions. The results also confirm that the Ti/TiH x /NATO has a higher kinetic rate constant and decolorization efficiency for removal of the methylene blue compare to the Ti/NATO. The rate constant for the pseudo-first ordered reaction of methylene blue degradation showed high values of 350 x 10(-3) min(-1) for Ti/NATO and 440 x 10(-3) min(-1) for Ti/TiHx/NATO. 

  • 2.
    Acevedo Gomez, Yasna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. However, the drawback of this catalyst is that it does not tolerate impurities, and both hydrogen and oxygen may carry small amounts of impurities depending on the production sources. The purpose of this thesis is to understand the effect of two impurities that are less investigated, i.e., ammonia, which may accompany the hydrogen rich reformates from renewable sources, and nitrogen dioxide, which may come from air pollution. The mechanism of contamination and an adequate recovery method for the respective contaminant are studied. Additionally, electroplated bipolar plates with Ni-Mo and Ni-Mo-P coatings were tested as alternatives to stainless steel and carbon materials.

    The results show that ammonia not only provokes changes in the polymer membrane but also in the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR) and catalyst ionomer in both electrodes. The extent of performance recovery after the contamination depends on the concentration used and the exposure time. In contrast, nitrogen dioxide affects the catalyst in the electrode directly; the contamination is related to side reactions that are produced on the catalyst’s surface. However, NO2 is not attached strongly to the catalyst and it is possible to restore the performance by using clean air. The time the recovery process takes depends on the potential applied and the air flow.

    Finally, the evaluation of electroplated Ni-Mo and Ni-Mo-P on stainless steel by ex situ and in situ studies shows that these coatings reduce the internal contact resistance (ICR) and the corrosion rate of the stainless steel considerably. However, the in situ experiments show that phosphorus addition to the coating does not improve the fuel cell performance; thus, the Ni-Mo alloy is found to be a promising choice for electroplating stainless steel bipolar plates.

  • 3.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Effect of nitrogen dioxide impurities on PEM fuel cell performanceManuscript (preprint) (Other academic)
    Abstract [en]

    Air is the most practical and economical oxidant to feed to the cathode in a proton exchange membrane fuel cell (PEMFC). However, the air is accompanied by small amounts of impurities that affect the performance of the fuel cell. Among these, nitrogen dioxide is the impurity that has been least investigated, and its effect is not fully understood. In this study, a possible mechanism is proposed based on the contamination of the fuel cell at different concentrations and adsorption potentials, and by employing stripping cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results at different concentrations showed that the catalyst sites are blocked by the adsorption of NO2, and that there is a non-linear relationship between the concentration and degradation. The degradation is suggested to be related to the formation of intermediate species, as also shown by the pseudo-inductive impedance at the concentration of 100 and 200 ppm. Furthermore, the cyclic voltammetry showed that there is an oxidation to NO3- at 1.05 V, followed by the reduction of this specie to NO2- at 0.68 V, and a subsequent reduction of NO2- to N2O and/or NH2OH.

  • 4.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Performance recovery after contamination with nitrogen dioxide in a PEM fuel cellManuscript (preprint) (Other academic)
    Abstract [en]

    While the market of fuel cell vehicles is increasing, these vehicles will still coexist with combustion engine vehicles on the roads and will be exposed to an environment with significant amounts of contaminants that will decrease the durability of the fuel cell. In order to investigate different recovery methods, a PEM fuel cell is in this study contaminated with 100 ppm of NO2 at the cathode side. The possibility to recover the cell performance is studied by using different airflow rates, different current densities, and by subjecting the cell to successive polarization curves. The results show that the successive polarization curves are the best choice for recovery; it took 35 min to reach full recovery of cell performance, compared to 4.5 hours of recovery with pure air at 0.5 A cm-2 and 110 ml min-1. However, the performance recovery at a current density of 0.2 A cm-2 and air flow 275 ml min-1 was done in 66 min, which is also a possible alternative. Additionally, two operation techniques are suggested and compared during 7 h of operation; air recovery and air depletion. The air recovery technique shows to be a better choice than the air depletion technique.

  • 5.
    Benavente Araoz, Fabian Andres
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lundblad, Anders
    Res Inst Sweden, RISE, Div Safety & Transport Elect, SE-50462 Boras, Sweden..
    Campana, Pietro Elia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Zhang, Yang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Cabrera, Saul
    UMSA Univ Mayor San Andres, Carrera Ciencias Quim, Inst Invest Quim, La Paz, Bolivia..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Photovoltaic/battery system sizing for rural electrification in Bolivia: Considering the suppressed demand effect2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 519-528Article in journal (Refereed)
    Abstract [en]

    Rural electrification programs usually do not consider the impact that the increment of demand has on the reliability of off-grid photovoltaic (PV)/battery systems. Based on meteorological data and electricity consumption profiles from the highlands of Bolivian Altiplano, this paper presents a modelling and simulation framework for analysing the performance and reliability of such systems. Reliability, as loss of power supply probability (LPSP), and cost were calculated using simulated PV power output and battery state of charge profiles. The effect of increasing the suppressed demand (SD) by 20% and 50% was studied to determine how reliable and resilient the system designs are. Simulations were performed for three rural application scenarios: a household, a school, and a health centre. Results for the household and school scenarios indicate that, to overcome the SD effect, it is more cost-effective to increase the PV power rather than to increase the battery capacity. However, with an increased PV-size, the battery ageing rate would be higher since the cycles are performed at high state of charge (SOC). For the health centre application, on the other hand, an increase in battery capacity prevents the risk of electricity blackouts while increasing the energy reliability of the system. These results provide important insights for the application design of off-grid PV-battery systems in rural electrification projects, enabling a more efficient and reliable source of electricity.

  • 6.
    Bessman, Alexander
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Interactions between battery and power electronics in an electric vehicle drivetrain2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The electric machine and power electronics in electric and hybrid electric vehicles inevitably cause AC harmonics on the vehicle's DC-link. These harmonics can be partially filtered out by large capacitors, which today are overdimensioned in order to protect the vehicle's battery pack. This is done as a precaution, since it is not known whether ripple-current has any harmful effect on Li-ion  cells.

    We have measured and analyzed the ripple-current present in a hybrid electric bus, and found that a majority of the power was carried by frequencies in the range 100~Hz to 1~kHz. The single most energetic harmonic in this particular vehicle is believed to have been caused  by a misaligned resolver in the motor.

    We have also designed and built an advanced experimental set-up in order to study the effect of ripple-current on Li-ion cells in the lab. The set-up can cycle up to 16 cells simultaneously, with currents of up to 50~A including a superimposed AC signal with a frequency of up to 2~kHz. The cells' temperatures are controlled by means of a climate chamber. The set-up also includes a sophisticated safety system which automatically acts to prevent dangerous situations before they arise.

    Using this set-up we tested whether superimposing AC with a specific frequency improves the charging performance of Li-ion cells. Statistical analysis found no improvement over regular DC cycling, and a physics-based model explains the experimental findings.

    We have also investigated whether ripple-current accelerates the aging of Li-ion cells. Twelve cells were either calendar or cycle  aged for one year, with some cells being exposed to superimposed AC with a frequency of 1~Hz, 100~Hz, or 1~kHz. No effect was observed on any of capacity fade, power fade, or aging mechanism.

    Finally we also tested whether it is possible to heat Li-ion cells from low temperatures using only AC. We propose a method for AC heating of Li-ion cells, and open the discussion for generalizing the technique to larger battery packs.

    In conclusion, ripple-current has negligible effect on Li-ion cells, except for heating them slightly.

  • 7.
    Bessman, Alexander
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Soares, Rudi
    KTH, School of Electrical Engineering and Computer Science (EECS), Electromagnetic Engineering.
    Software documentation for current-rippleequipment2018Report (Other (popular science, discussion, etc.))
  • 8.
    Bessman, Alexander
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Soares, Rúdi
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Wallmark, Oskar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Svens, Pontus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Aging effects of AC harmonics on lithium-ion cells2019In: Journal of Energy Storage, E-ISSN 2352-152X, Vol. 21, p. 741-749Article in journal (Refereed)
    Abstract [en]

    With the vehicle industry poised to take the step into the era of electric vehicles, concerns have been raised that AC harmonics arising from switching of power electronics and harmonics in electric machinery may damage the battery. In light of this, we have studied the effect of several different frequencies on the aging of 28 Ah commercial NMC/graphite prismatic lithium-ion battery cells. The tested frequencies are 1 Hz, 100 Hz, and 1 kHz, all with a peak amplitude of 21 A. Both the effect on cycled cells and calendar aged cells is tested. The cycled cells are cycled at a rate of 1C:1C, i.e., 28 A during both charging and discharging, with the exception of a period of constant voltage at the end of every charge. After running for one year, the cycled cells have completed approximately 2000 cycles. The cells are characterized periodically to follow how their capacities and power capabilities evolve. After completion of the test about 80% of the initial capacity remained and no increase in resistance was observed. No negative effect on either capacity fade or power fade is observed in this study, and no difference in aging mechanism is detected when using non-invasive electrochemical methods of post mortem investigation.

  • 9.
    Carlson, Annika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Electrochemical properties of alternative polymer electrolytes in fuel cells2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fuel cells, using hydrogen as energy carrier, allow chemically‑stored energy to be utilized for many applications, including balancing the electrical grid and the propulsion of vehicles. To make the fuel cell technology more accessible and promote a sustainable energy society, this thesis focuses on alternative polymer electrolytes, as they can potentially lead to a lower cost and a more environmentally‑friendly fuel cell. The main subject is anion exchange membrane fuel cells (AEMFCs), for which the importance of gas diffusion electrode morphology and platinum electrode reactions are investigated. Properties of the membrane such as water flux during operation are evaluated. Furthermore, novel polymer electrolytes are studied: variations of poly(phenylene oxide)‑based membranes in AEMFCs; and cellulose‑based membranes in a proton exchange membrane fuel cell (PEMFC).

     

    The AEMFC results show that the performance is dependent on the electrode morphology. Electrochemical experiments in a hydrogen/hydrogen cell combined with modelling show that the hydrogen oxidation reaction proceeds through the Tafel‑Volmer reaction pathway on platinum. Application of the model in a hydrogen/oxygen cell shows that the cathode has the slowest reaction rate. During operation, the water flux through the membrane is directed from the anode where water is produced to the cathode where it is consumed. This leads to an increase in water content at both electrodes, which implies that electrode flooding is more likely than dry‑out during operation. The effect of membrane thickness on water flux is shown to be larger than the effect of polymer structure for several different types of poly(phenylene oxide)‑based membranes. The comparison of these polymers also indicates that a high conductivity, for the relative humidity achieved in a fuel cell, promotes increased performance. Finally, the study of cellulose-based membranes in a PEMFC shows that cellulose as a renewable, natural polymer has promising properties, such as stable conductivity for relative humidities above 65 % and a low gas permeability.

  • 10.
    Carlson, Annika
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Ekström, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. COMSOL.
    Grimler, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    An Electrochemical Impedance Study of the Hydrogen Electrode Reaction in the Anion Exchange Membrane Fuel CellManuscript (preprint) (Other academic)
  • 11.
    Carlson, Annika
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Olsson, Joel
    Lund University.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Jannasch, Patric
    Lund University.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Fuel cell evaluation of anion exchange membranes based on PPO with different cation placementManuscript (preprint) (Other academic)
  • 12.
    Carlson, Annika
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Shapturenka, Pavel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Electrode parameters and operating conditions influencing the performance of anion exchange membrane fuel cells2018In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 277, p. 151-160Article in journal (Refereed)
    Abstract [en]

    A deeper understanding of porous electrode preparation and performance losses is necessary to advance the anion exchange membrane fuel cell (AEMFC) technology. This study has investigated the performance losses at 50 °C for varied: Tokuyama AS-4 ionomer content in the catalyst layer, Pt/C loading and catalyst layer thickness at the anode and cathode, relative humidity, and anode catalyst. The prepared gas diffusion electrodes in the interval of ionomer-to-Pt/C weight ratio of 0.4–0.8 or 29–44 wt% ionomer content show the highest performance. Varying the loading and catalyst layer thickness simultaneously shows that both the cathode and the anode influence the cell performance. The effects of the two electrodes are shown to vary with current density and this is assumed to be due to non-uniform current distribution throughout the electrodes. Further, lowering the relative humidity at the anode and cathode separately shows small performance losses for both electrodes that could be related to lowered ionomer conductivity. Continued studies are needed to optimize, and understand limitations of, each of the two electrodes to obtain improved cell performance.

  • 13.
    Chiche, Ariel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Stenius, Ivan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Sizing the energy system on long-range AUV2018In: AUV 2018 - 2018 IEEE/OES Autonomous Underwater Vehicle Workshop, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2018Conference paper (Refereed)
    Abstract [en]

    Autonomous Underwater Vehicles (AUVs) can be used for various types of unmanned missions. Currently, the most common energy storage technique is rechargeable batteries. In order to increase the range and endurance of these vehicles, where volume is a limiting factor, fuel cell systems could offer a very attractive solution. Fuel cell systems can have a drastically increased specific energy compared to batteries and are now starting to become well developed technologies. However, in an underwater environment, both hydrogen and oxygen needs to be stored for the fuel cell. This study presents a sizing tool that compares the weight and volume to balance fuel cell and battery energy storage solutions for some selected AUV missions. The main result is the shifting point between batteries and hybrid battery/fuel cell system in terms of volume efficiency, where longer missions favor the latter.

  • 14.
    Cornell, Ann
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Rodrigo, Manuel
    Univ Castilla La Mancha, Dept Chem Engn, Ciudad Real, Spain..
    Bouzek, Karel
    Univ Chem & Technol Prague, Prague, Czech Republic..
    Special Issue: 11th European Symposium in Electrochemical Engineering (ESEE 11) Foreword2018In: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 48, no 6, p. 559-560Article in journal (Refereed)
  • 15.
    Ekström, Henrik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Fridholm, B.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Comparison of lumped diffusion models for voltage prediction of a lithium-ion battery cell during dynamic loads2018In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 402, p. 296-300Article in journal (Refereed)
    Abstract [en]

    Three different time-dependent lumped battery models are presented, using a limited set of only either three or four fitting parameters. The models all include one linear (resistive), one non-linear (kinetic) and one time-dependent element, the latter describing the diffusive processes in the battery. The voltage predictive capabilities of the models versus experimental dynamic load data for a plug-in hybrid vehicle battery are compared. It is shown that models based on a diffusion equation in an idealized particle perform similarly to a model based on an RC (resistive-capacitor) pair. In addition, by exchanging the RC element by a diffusion equation in an idealized particle it is also shown that it is possible to reduce the number of needed fitting parameters by one. 

  • 16.
    Endrodi, Balazs
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Smulders, Vera
    Univ Twente, Fac Sci & Technol, MESA Inst Nanotechnol, PhotoCatalyt Synth Grp, Meander 229,POB 217, NL-7500 AE Enschede, Netherlands..
    Simic, Nina
    Nouryon, SE-44580 Bohus, Sweden..
    Wildlock, Mats
    Nouryon, SE-44580 Bohus, Sweden..
    Mul, Guido
    Univ Twente, Fac Sci & Technol, MESA Inst Nanotechnol, PhotoCatalyt Synth Grp, Meander 229,POB 217, NL-7500 AE Enschede, Netherlands..
    Mei, Bastian
    Univ Twente, Fac Sci & Technol, MESA Inst Nanotechnol, PhotoCatalyt Synth Grp, Meander 229,POB 217, NL-7500 AE Enschede, Netherlands..
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    In situ formed vanadium-oxide cathode coatings for selective hydrogen production2019In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 244, p. 233-239Article in journal (Refereed)
    Abstract [en]

    Electrode selectivity towards hydrogen production is essential in various conversion technologies for renewable energy, as well as in different industrial processes, such as the electrochemical production of sodium chlorate. In this study we present sodium metavanadate as a solution additive, inducing selective cathodic formation of hydrogen in the presence of various other reducible species such as hypochlorite, chlorate, oxygen, nitrate, hydrogen-peroxide and ferricyanide. During electrolysis a vanadium-oxide coating forms from the reduction of sodium metavanadate, explaining the observed enhanced selectivity. The hydrogen evolution reaction proceeds without significantly altered kinetics on such in situ modified electrode surfaces. This suggests that the reaction takes place at the interface between the electrode surface and the protective film, which acts as a diffusion barrier preventing the unwanted species to reach the electrode surface.

  • 17.
    Endrodi, Balazs
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Sch Engn Sci Chem Univ Szeged, Dept Phys Chem & Mat Sci, Rerrich Bela Sq 1, H-6720 Szeged, Hungary..
    Stojanovic, Aleksandra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cuartero, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Simic, Nina
    Nouryon Pulp & Performance Chem AB, Farjevagen 1, SE-44580 Bohus, Sweden..
    Wildlock, Mats
    Nouryon Pulp & Performance Chem AB, Farjevagen 1, SE-44580 Bohus, Sweden..
    de Marco, Roland
    Univ Sunshine Coast, Fac Sci Hlth Educ & Engn, Sippy Downs Dr 90, Sippy Downs, Qld 4556, Australia.;Univ Queensland, Sch Chem & Mol Biosci, Cooper Rd 68, Brisbane, Qld 4072, Australia..
    Crespo, Gaston A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Selective Hydrogen Evolution on Manganese Oxide Coated Electrodes: New Cathodes for Sodium Chlorate Production2019In: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 7, no 14, p. 12170-12178Article in journal (Refereed)
    Abstract [en]

    The safety and feasibility of industrial electrochemical production of sodium chlorate, an important chemical in the pulp and paper industry, depend on the selectivity of the electrode processes. The cathodic reduction of anodic products is sufficiently suppressed in the current technology by the addition of chromium(VI) to the electrolyte, but due to the high toxicity of these compounds, alternative pathways are required to maintain high process efficiency. In this paper, we evaluate the electrochemical hydrogen evolution reaction kinetics and selectivity on thermally formed manganese oxide-coated titanium electrodes in hypochlorite and chlorate solutions. The morphology and phase composition of manganese oxide layers were varied via alteration of the annealing temperature during synthesis, as confirmed by scanning electron microscopy, X-ray diffraction, synchrotron radiation X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy measurements. As shown in mass spectroscopy coupled electrochemical measurements, the hydrogen evolution selectivity in hypochlorite and chlorate solutions is dictated by the phase composition of the coating. Importantly, a hydrogen evolution efficiency of above 95% was achieved with electrodes of optimized composition (annealing temperature, thickness) in hypochlorite solutions. Further, these electrode coatings are nontoxic and Earth-abundant, offering the possibility of a more sustainable chlorate production.

  • 18.
    Endrodi, Balázs
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Department of Physical Chemistry and Materials Science, University of Szeged, Szeged, Hungary.
    Sandin, Staffan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wildlock, Mats
    Simic, Nina
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Suppressed oxygen evolution during chlorateformation from hypochlorite in the presenceof chromium(VI)2019In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 94, no 5, p. 1520-1527Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Chromium(VI) is a crucial electrolyte component in industrial chlorate production. Due to its toxicity, iturgently needs to be abandoned and its functions fulfilled by new solutions. In the industrial production of sodium chlorate,homogeneous decomposition of the hypochlorite intermediate to chlorate is a key step. As a competing loss reaction,hypochlorite can decompose to oxygen. How chromium(VI) affects these reactions is not well understood.

    RESULTS: This work shows, for the first time, that chromium(VI) selectively accelerates the chlorate formation from hypochloriteboth in dilute and concentrated, industrially relevant solutions. The effect of the ionic strength and the specific contributionof different electrolyte components were systematically studied. By simultaneously measuring the concentration decayof hypochlorite (UV–vis spectroscopy) and the oxygen formation (mass spectrometry), both the rate and the selectivity of thereactions were evaluated.

    CONCLUSION: In the presence of chromium(VI) the hypochlorite decomposition is described by the sum of an uncatalyzedand a parallel catalyzed reaction, where oxygen only forms in the uncatalyzed reaction. When removing chromium(VI),the homogeneous oxygen formation increases, causing economic and safety concerns. The need for a catalyst selectivefor chlorate formation is emphasized.

  • 19.
    Endrődi, Balázs
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Sandin, Staffan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Smulders, V.
    Simic, N.
    Wildlock, M.
    Mul, G.
    Mei, B. T.
    Cornell, Ann
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Towards sustainable chlorate production: The effect of permanganate addition on current efficiency2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 182, p. 529-537Article in journal (Refereed)
    Abstract [en]

    Sodium dichromate is an essential solution additive for the electrocatalytic production of sodium chlorate, assuring selective hydrogen evolution. Unfortunately, the serious environmental and health concerns related to hexavalent chromium mean there is an urgent need to find an alternative solution to achieve the required selectivity. In this study sodium permanganate is evaluated as a possible alternative to chromate, with positive results. The permanganate additive is stable in hypochlorite-containing solutions, and during electrolysis a thin film is reductively deposited on the cathode. The deposit is identified as amorphous manganese oxide by Raman spectroscopic and X-ray diffraction studies. Using different electrochemical techniques (potentiodynamic measurements, galvanostatic polarization curves) we demonstrate that the reduction of hypochlorite is suppressed, while the hydrogen evolution reaction can still proceed. In addition, the formed manganese oxide film acts as a barrier for the reduction of dissolved oxygen. The extent of hydrogen evolution selectivity in hypochlorite solutions was quantified in an undivided electrochemical cell using mass spectrometry. The cathodic current efficiency is significantly enhanced after the addition of permanganate, while the effect on the anodic selectivity and the decomposition of hypochlorite in solution is negligible. Importantly, similar results were obtained using electrodes with manganese oxide films formed ex situ. In conclusion, manganese oxides show great promise in inducing selective hydrogen evolution, and may open new research avenues to the rational design of selective cathodes, both for the chlorate process and for related processes such as photocatalytic water splitting.

  • 20.
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Electrochemical evaluation of new materials in polymer electrolyte fuel cells2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Polymer electrolyte fuel cells (PEFC) convert the chemical energy in hydrogen to electrical energy and heat, with the only exhaust being water. Fuel cells are considered key in achieving a sustainable energy sector. The main obstacles to wide scale commercialization are cost and durability. The aim of this thesis is to evaluate new materials for PEFC to potentially lower cost and increase durability. To lower the amount of expensive platinum catalyst in the fuel cell, the activities of Pt-rare earth metal (REM) alloy catalysts have been tested. To improve the lifetime of the carbon support, the carbon corrosion properties of multi walled carbon nanotubes have been evaluated. To reduce the overall cost of fuel cell stacks, carbon coated and metal coated bipolar plates have been tested. To increase the performance and lifetime of anion exchange membranes, the water transport has been studied.

    The results show that the Pt-REM catalysts had at least two times higher specific activity than pure platinum, and even higher activities should be obtainable if the surface structures are further refined.

    Multi-walled carbon nanotubes had lower carbon corrosion than conventional carbon Vulcan XC-72. However, once severely corroded their porous structure collapsed, causing major performance losses.

    The carbon coated metallic bipolar plates showed no significant increase of internal contact resistance (ICR) by cycling, suggesting that these coatings are stable in fuel cells. The NiMo- and NiMoP coated bipolar plates showed low ICR, however, presence of the coated bipolar plates caused secondary harmful effects on the polymer membrane and ionomer.

    Considering the water transport through anion exchange membranes it was found that most membranes showed very similar water transport properties, with more water detected at both the anode and cathode when a current was applied. The most significant factor governing the water transport properties was the membrane thickness, with thicker membranes reducing the backflow of water from anode to cathode.

    The results indicate that all of the new tested materials have the capability to improve the lifetime and reduce cost and thereby improve the overall performance of PEFC.

  • 21.
    Eriksson, Björn
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Grimler, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Carlson, Annika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Ekström, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Quantifying water transport in anion exchange membrane fuel cells2019In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 44, no 10, p. 4930-4939Article in journal (Refereed)
    Abstract [en]

    Sufficient water transport through the membrane is necessary for a well-performing anion exchange membrane fuel cell (AEMFC). In this study, the water flux through a membrane electrode assembly (MEA), using a Tokuyama A201 membrane, is quantified using humidity sensors at the in- and outlet on both sides of the MEA. Experiments performed in humidified inert gas at both sides of the MEA or with liquid water at one side shows that the aggregation state of water has a large impact on the transport properties. The water fluxes are shown to be approximately three times larger for a membrane in contact with liquid water compared to vaporous. Further, the flux during fuel cell operation is investigated and shows that the transport rate of water in the membrane is affected by an applied current. The water vapor content increases on both the anode and cathode side of the AEMFC for all investigated current densities. Through modeling, an apparent water drag coefficient is determined to −0.64, indicating that the current-induced transport of water occurs in the opposite direction to the transport of hydroxide ions. These results implicate that flooding, on one or both electrodes, is a larger concern than dry-out in an AEMFC.

  • 22.
    Eriksson, Björn
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Montserrat-Sisó, Gerard
    Chalmers University of Technology.
    Brown, Rosemary
    Chalmers University of Technology.
    Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wickman, Björn
    Chalmers University of Technology.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Evaluation of rare earth metal alloy catalysts for the oxygen reduction reaction in proton exchange membrane fuel cellsManuscript (preprint) (Other academic)
  • 23.
    Gomez, Yasna Acevedo
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Oyarce, Alejandro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Ammonia contamination of a proton exchange membrane fuel cell2018In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, no 3, p. F189-F197Article in journal (Refereed)
    Abstract [en]

    Reformate hydrogen from biogas is an attractive fuel alternative for energy conversion in PEM fuel cells. However, in the reformate traces of ammonia may be found, e.g. if the biogas is produced from agricultural resources. In this investigation the effect of ammonia in the fuel gas, on each part of the fuel cell, is studied by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), symmetrical hydrogen cell (H2|H2)- and real fuel cell operation. A considerable degradation in performance is observed by introducing 200 ppm ammonia. The results show that ammonia not only affects the polymer electrolyte membrane but also the oxygen reduction reaction (ORR) and catalyst ionomer in both electrodes, whereas the hydrogen oxidation reaction (HOR) is the worst affected. In the short-term, the performance is reversible if running the cell on neat hydrogen after ammonia exposure, but this does not apply for long-term exposure. A mitigation method with air bleed is tested but gives no improvement of the performance.

  • 24.
    Grimler, Henrik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Carlson, Annika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Ekström, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. COMSOL.
    Lagergren, Carina
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Determination of kinetic parameters for the oxygen reduction reaction on platinum in an AEMFCManuscript (preprint) (Other academic)
  • 25.
    Guccini, Valentina
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
    Carlson, Annika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Yu, Shun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden .
    Lindbergh, Göran
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Salazar-Alvarez, German
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden .
    Highly proton conductive membranes based on carboxylated cellulose nanofibres and their performance in proton exchange membrane fuel cells2019In: Journal of Materials Chemistry A, ISSN 2050-7488Article in journal (Refereed)
    Abstract [en]

    The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in situ as a function of CNF surface charge density (600 and 1550 μmol g−1), counterion (H+ or Na+), membrane thickness and fuel cell relative humidity (RH 55 to 95%). The structural evolution of the membranes as a function of RH, as measured by Small Angle X-ray Scattering, shows that water channels are formed only above 75% RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (H+ or Na+). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm−1 at 30 °C between 65 and 95% RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈30% thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.

  • 26.
    Hagberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Carbon Fibres for Multifunctional Lithium-Ion Batteries2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The transportation industry today faces many challenges because of the rapid movement towards electrification. One major challenge is the weight of the battery, which limits the effectiveness of the vehicles. One of the possible routes to reduce the weight on a system-level is introducing structural batteries, batteries that simultaneously storeenergy and hold a mechanical load. Placing these batteries in a load-bearing part of the structure reduces weight and increases effectiveness on a system level. Carbon fibres are especially suited for structural batteries because of the high performance as reinforcement material in a polymer composite, as well as the ability to insert lithium to function as negative electrodes in batteries.

    Another field that has attracted attention the latest years is flexible batteries due to the emerging of flexible displays and wearable electronics. Carbon fibres can be a suitable material in flexible batteries due to the good conductivity, mechanical integrity and ability to forman integrated flexible film with cellulose nanofibrils (CNF) as binder.

    This thesis focuses on the usage of carbon fibres in structural and flexible batteries. Lignin based and commercial carbon fibres are evaluated as negative electrodes using a combination of electrochemical methods, material characterization and mechanical testing. Further, the diffusion is characterized using nuclear magnetic resonance spectroscopy, revealing an inequality of axial and radial diffusion in carbon fibres. The carbon fibres with a largely disordered structure show most promise as a negative electrode, with a capacity similar to graphite and having a high coulombic efficiency.

    Carbon fibres used as current collectors are evaluated as well, both continuous LiFePO4 coated carbon fibres with electrophoretic deposition for structural positive electrode applications and chopped carbonfibres bounded by CNF as a layer in a flexible electrode. The LiFePO4 coated carbon fibres show promise as a structural electrode with moderatecapacity, high coulombic efficiency, good rate performance and good adhesion between fibres and coating. The flexible electrodes with carbon fibres as current collectors perform well with a high capacity, good rate performance, low weight and high flexibility. The electrodes withstand bending for 4000 times without any performance degradation.

  • 27.
    Hagberg, Johan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Maples, Henry A.
    Polymer and Composite Engineering (PaCE) Group, Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna, Währinger Straße 42, A-1090 Vienna, Austria .
    Alvim, Kayne S. P.
    Polymer and Composite Engineering (PaCE) Group, Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna, Währinger Straße 42, A-1090 Vienna, Austria .
    Xu, Johanna
    Polymeric Composite Materials, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden .
    Johannisson, Wilhelm
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Bismarck, Alexander
    Polymer and Composite Engineering (PaCE) Group, Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna, Währinger Straße 42, A-1090 Vienna, Austria ; Polymer and Composite Engineering (PaCE) Group, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK .
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lithium iron phosphate coated carbon fiber electrodes for structural lithium ion batteries2018In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 162, p. 235-243Article in journal (Refereed)
    Abstract [en]

    A structural lithium ion battery is a material that can carry load and simultaneously be used to store electrical energy. We describe a path to manufacture structural positive electrodes via electrophoretic deposition (EPD) of LiFePO4 (LFP), carbon black and polyvinylidene fluoride (PVDF) onto carbon fibers. The carbon fibers act as load-bearers as well as current collectors. The quality of the coating was studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. The active electrode material (LFP particles), conductive additive (carbon black) and binder (PVDF) were found to be well dispersed on the surface of the carbon fibers. Electrochemical characterization revealed a specific capacity of around 60–110 mAh g−1 with good rate performance and high coulombic efficiency. The cell was stable during cycling, with a capacity retention of around 0.5 after 1000 cycles, which indicates that the coating remained well adhered to the fibers. To investigate the adhesion of the coating, the carbon fibers were made into composite laminae in epoxy resin, and then tested using 3-point bending and double cantilever beam (DCB) tests. The former showed a small difference between coated and uncoated carbon fibers, suggesting good adhesion. The latter showed a critical strain energy release rate of ∼200–600 J m−2 for coated carbon fibers and ∼500 J m−2 for uncoated fibers, which also indicates good adhesion. This study shows that EPD can be used to produce viable structural positive electrodes.

  • 28.
    Harnden, Ross
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Peuvot, Kevin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Multifunctional Performance of Sodiated Carbon Fibers2018In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, no 13, p. B616-B622Article in journal (Refereed)
    Abstract [en]

    An investigation is conducted into the potential for sodiated PAN-based carbon fibers (CFs) to be used in multifunctional actuation, sensing, and energy harvesting. Axial CF expansion/contraction is measured during sodiation/desodiation using operando strain measurements. The reversible expansion/contraction is found to be 0.1% - which is lower than that of lithiated CFs. The axial sodiation expansion occurs in two well-defined stages, corresponding to the sloping and plateau regions of the galvanostatic cycling curve. The results indicate that the sloping region most likely corresponds to sodium insertion between graphitic sheets, while the plateau region corresponds to sodium insertion in micropores. A voltage-strain coupling is found for the CFs, with a maximum coupling factor of 0.15 +/- 0.01 V/unit strain, which could be used for strain sensing in multifunctional structures. This voltage-strain coupling is too small to be exploited for harvesting mechanical energy. The measured axial expansion is further used to estimate the capacity loss due to solid electrolyte interphase (SEI) formation, as well as capacity loss due to sodium trapped in the CF microstructure. The outcomes of this research suggest that sodiated CFs show some potential for use as actuators and sensors in future multifunctional structures, but that lithiated CFs show more promise.

  • 29.
    Jannat, Sharif
    et al.
    Isfahan Univ Technol, Dept Mat Engn, Esfahan 8415683111, Iran..
    Rashtchi, Hamed
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Isfahan Univ Technol, Dept Mat Engn, Esfahan 8415683111, Iran..
    Atapour, Masoud
    Isfahan Univ Technol, Dept Mat Engn, Esfahan 8415683111, Iran..
    Golozar, Mohammad Ali
    Isfahan Univ Technol, Dept Mat Engn, Esfahan 8415683111, Iran..
    Elmkhah, Hassan
    Bu Ali Sina Univ, Fac Engn, Hamadan 6517838695, Iran..
    Zhiani, Mohammad
    Isfahan Univ Technol, Dept Chem, Esfahan 8415683111, Iran..
    Preparation and performance of nanometric Ti/TiN multi-layer physical vapor deposited coating on 316L stainless steel as bipolar plate for proton exchange membrane fuel cells2019In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 435, article id 226818Article in journal (Refereed)
    Abstract [en]

    The current research mainly focuses on surface properties, corrosion resistance and interfacial contact resistance (ICR) of nanometric titanium/titanium nitride (Ti/TiN) multi-layer coating deposited on 316L stainless steel via physical vapor deposition (PVD) technique for using in proton exchange membrane fuel cell (PEMFC) bipolar plate (BPP) application. The phase and microstructure of the coated BPPs is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle examinations. The performance of the BPPs is investigated by electrochemical corrosion tests including electrochemical impedance spectroscopy (EIS), potentiodynamic and potentiostatic polarization tests at two conditions including at ambient temperature and in the simulated PEMFC cathode environment. Electrochemical test results reveal that the Ti/TiN coating increases the polarization resistance of 316L stainless steel by 26 orders of magnitude at ambient temperature and by 1000 orders of magnitude in the simulated PEMFC cathode environment. The corresponding ICR of the BPPs is measured ex-situ in a PEMFC set-up. It is observed that the coated BPP has ICR value of 11 and 18 m Omega cm(2) before and after potentiostatic polarization, respectively. Hence, the Ti/TiN coating studied in this work has promising properties as BPP material and is potentially suitable alternative to replace the graphite BPP in PEMFC.

  • 30.
    Johannisson, Wilhelm
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Zackrisson, Mats
    Jönsson, Christina
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Modelling and design of structural batteries with life cycle assessment2019Conference paper (Other academic)
    Abstract [en]

    A multifunctional structural battery consisting of carbon fibers, lithium-electrode coatings and a structural battery electrolyte is investigated with an analytical bottom-up model. This model has a multiphysics approach, calculating both mechanical properties and electrical energy storage. The intention of the model is twofold; first, calculating the potential mass saving with using a structural battery instead of the combination of a monofunctional carbon fiber composite and a monofunctional lithium ion battery. Second, the model is used to investigate the behavior of the mass saving due to changing variables of the structural battery. This variable sensitivity analysis is made in order to understand the behavior of the structural battery and its sensitivity to the different construction variables. The results show that the structural battery can save up to 26% of mass compared to the monofunctional parts.

    Next, the model of the structural battery is further utilized in a life cycle assessment, where the manufacturing, usage and recycling of the structural battery is investigated. The life cycle assessment examines the structural battery as the roof of an electric vehicle. This analysis is compared to the same assessment for a steel roof and standard lithium ion batteries, which shows that manufacturing the carbon fibers and structural battery with clean energy is most important for decreasing the emissions from manufacturing.

  • 31.
    Johannisson, Wilhelm
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Model of a structural battery and its potential for system level mass savings2019In: Multifunctional Materials, ISSN 2399-7532, article id 035002Article in journal (Refereed)
    Abstract [en]

    Structural batteries are materials that can carry mechanical load while storing electrical energy. This is achieved by combining the properties of carbon fiber composites and lithium ion batteries. There are many design parameters for a structural battery and in order to understand their impact and importance, this paper presents a model for multifunctional performance. The mechanical behavior and electrical energy storage of the structural battery are matched to the mechanical behavior of a conventional carbon fiber composite, and the electrical energy storage of a standard lithium ion battery. The latter are both monofunctional and have known performance and mass. In order to calculate the benefit of using structural batteries, the mass of the structural battery is compared to that of the two monofunctional systems. There is often an inverse relationship between the mechanical and electrochemical properties of multifunctional materials, in order to understand these relationships a sensitivity analysis is performed on variables for the structural battery. This gives new insight into the complex multifunctional design of structural batteries.

    The results show that it is possible to save mass compared to monofunctional systems but that it depends strongly on the structure it is compared with. With improvements to the design of the structural battery it would be possible to achieve mass saving compared to state-of-the-art composite laminates and lithium ion batteries.

  • 32.
    Kanninen, Petri
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Davodi, Fatemeh
    Aalto University.
    Buan, Marthe
    Aalto University.
    Sorsa, Olli
    Aalto University.
    Kallio, Tanja
    Aalto University.
    Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Carbon corrosion properties and performance of multi-walled carbon nanotube support with and without nitrogen-functionalization in fuel cell electrodesIn: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859Article in journal (Other academic)
    Abstract [en]

  • 33.
    Kanninen, Petri
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Aalto Univ, Dept Chem & Mat Sci, POB 16100, Aalto 00076, Finland.
    Kallio, Tanja
    Aalto Univ, Dept Chem & Mat Sci, POB 16100, Aalto 00076, Finland..
    Activation of commercial Pt/C catalyst toward glucose electro-oxidation by irreversible Bi adsorption2018In: Journal of Energy Challenges and Mechanics, ISSN 2095-4956, E-ISSN 2056-9386, Vol. 27, no 5, p. 1446-1452Article in journal (Refereed)
    Abstract [en]

    The effect of irreversibly adsorbed Bi on commercial Pt/C catalyst toward glucose electro-oxidation reaction (GOR) in different electrolytes (acidic, neutral, alkaline) is studied. Bi is successfully deposited on Pt/C from Bi3+ containing acidic solution from 0 to 90% coverage degree. The stability of the Bi layer in acid and alkaline corresponded to previous studies and started to dissolve at 0.7 V and 0.8 V versus reversible hydrogen electrode (RHE), respectively. However, in neutral phosphate buffer the layer showed remarkable stability to at least 1.2 V versus RHE. Bi modification at low (20%) and high (80%) coverage showed the highest increase in the activity of Pt/C toward GOR by a factor up to 7 due to the increased poisoning resistance of the modified catalyst. The effect of poisoning was especially reduced at high Bi coverage (80%), which shows that adsorbate blocked by Bi through the third-body effect is effective. Finally, with or without Bi modification GOR on Pt/C was most active in alkaline conditions.

  • 34.
    Kim, Hyeyun
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Guccini, Valentina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Stockholm Univ, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden.
    Lu, Huiran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Northvolt AB, Gamla Brogatan 26, SE-11120 Stockholm, Sweden.
    Salazar-Alvarez, German
    Stockholm Univ, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Lithium Ion Battery Separators Based On Carboxylated Cellulose Nanofibers From Wood2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 2, p. 1241-1250Article in journal (Refereed)
    Abstract [en]

    Carboxylated cellulose nanofibers, prepared by TEMPO-mediated oxidation (TOCN), were processed into asymmetric mesoporous membranes using a facile paper-making approach and investigated as lithium ion battery separators. Membranes made of TOCN with sodium carboxylate groups (TOCN-COO-Na+) showed capacity fading after a few cycles of charging and discharging. On the other hand, its protonated counterpart (TOCN-COOH) showed highly improved electrochemical and cycling stability, displaying 94.5% of discharge capacity maintained after 100 cycles at 1 C rate of charging and discharging. The asymmetric surface porosity of the membranes must be considered when assembling a battery cell as it influences the rate capabilities of the battery. The wood-based TOCN-membranes have a good potential as an ecofriendly alternative to conventional fossil fuel-derived separators without adverse side effects.

  • 35.
    Ko, Jing Ying
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Varini, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ekström, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. COMSOL AB, Sweden.
    Klett, Matilda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Porous Electrode Model with Particle Stress Effects for Li(Ni1/3Co1/3Mn1/3)O2 Electrode2019In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111Article in journal (Refereed)
    Abstract [en]

    A porous electrode model, incorporating particle stress effects, is developed for the electrode kinetic processes in the positive Li(Ni1/3Mn1/3Co1/3)O2 or NMC111 electrode. The model is used to analyze experimental data from galvanostatic intermittent titration technique (GITT) during charging at the beginning of life. The equilibrium potential accounts for the influence of mechanical stress in the electrode particles. While the standard Newman-based model proves unable to capture the dynamic performance of NMC111, the extended model with stress allows good fits of the GITT responses for NMC half cells for a voltage range from 3.7–4.1 V vs Li/Li+ at 10°C, 25°C and 40°C. Four physical parameters are extracted to analyze the underlying diffusive, kinetic, thermodynamic and stress phenomena from polarization to relaxation during a GITT transient. Strong dependencies of the kinetic rate constant k, slope of the open-circuit potential curve dEconc/dxpos and stress proportionality factor ϒstress with lithium concentration are found. The effective diffusion coefficients Ds,eff are ∼10−14 – 10−13 cm2/s across voltages and temperatures. Diffusion limitation and particle surface stress are more profound at higher voltages and at higher temperatures. This leads to large lithium concentration gradient near particle surface, requiring longer relaxation time during GITT.

  • 36.
    Leijonmarck, Simon
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Carlson, T.
    Hellqvist Kjell, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Asp, L. E.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Maples, H.
    Bismarck, A.
    Coated carbon fibre battery half-cells for structural battery composites2013In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2013, p. 5342-5343Conference paper (Refereed)
  • 37.
    Lindahl, Niklas
    et al.
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Groenbeck, Henrik
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wickman, Bjoern
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Fuel Cell Measurements with Cathode Catalysts of Sputtered Pt3Y Thin Films2018In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, no 9, p. 1438-1445Article in journal (Refereed)
    Abstract [en]

    Fuel cells are foreseen to have an important role in sustainable energy systems, provided that catalysts with higher activity and stability are developed. In this study, highly active sputtered thin films of platinum alloyed with yttrium (Pt3Y) are deposited on commercial gas diffusion layers and their performance in a proton exchange membrane fuel cell is measured. After acid pretreatment, the alloy is found to have up to 2.5 times higher specific activity than pure platinum. The performance of Pt3Y is much higher than that of pure Pt, even if all of the alloying element was leached out from parts of the thin metal film on the porous support. This indicates that an even higher performance is expected if the structure of the Pt3Y catalyst or the support could be further improved. The results show that platinum alloyed with rare earth metals can be used as highly active cathode catalyst materials, and significantly reduce the amount of platinum needed, in real fuel cells.

  • 38.
    Lindberg, Jonas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Endrodi, Balazs
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Univ Szeged, Dept Phys Chem & Mat Sci, H-6720 Szeged, Hungary..
    Avall, Gustav
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Johansson, Patrik
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Li Salt Anion Effect on O-2 Solubility in an Li-O-2 Battery2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 4, p. 1913-1920Article in journal (Refereed)
    Abstract [en]

    For the promising Li-O-2 battery to be commercialized, further understanding of its constituents is needed. This study deals with the role of O-2 in Li-O-2 batteries, both its influence on electrochemical performance and its solubility in lithium-salt-containing dimethyl sulfoxide (DMSO) electrolytes. Experimentally, the electrochemical performance was evaluated using cylindrical ultramicroelectrodes. Two independent techniques, using a mass spectrometer and an optical sensor, were used to evaluate the O-2 solubility, expressed as Henry's constant. Furthermore, the ionic conductivity, dynamic viscosity, and density were also measured. Density functional theory calculations were made of the interaction energy between O-2 and the different species in the electrolytes. When varying O-2 partial pressure, the current was larger at high pressures confirming that the O-2 concentration is of key importance when studying the kinetics of this system. Compared with neat DMSO, the O-2 solubility increased with addition of LiTFSI and decreased with addition of LiClO4, indicating that the salt influences the solubility. This solubility trend is best explained in terms of apparent molar volume and interaction energy between O-2 and the salt anion. In conclusion, this study shows the importance of O-2 concentration, not just its partial pressure, and that the choice of Li salt can make this concentration increase or decrease.

  • 39.
    Lu, Huiran
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Hagberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Flexible and Lightweight Lithium-Ion Batteries Based on Cellulose Nanofibrils and Carbon Fibers2018In: BATTERIES-BASEL, ISSN 2313-0105, Vol. 4, no 2, article id 17Article in journal (Refereed)
    Abstract [en]

    Flexible, low-weight electrodes with integrated current collectors based on chopped polyacrylonitrile carbon fibers (CF) were produced using an easy, aqueous fabrication process, where only 4 wt% of TEMPO-oxidized cellulose nanofibrils (CNF) were used as the binder. A flexible full cell was assembled based on a LiFePO4 (LFP) positive electrode with a CF current collector and a current collector-free CF negative electrode. The cell exhibited a stable specific capacity of 121 mAh g(-1) based on the LFP weight. The CF in the negative electrode acted simultaneously as active material and current collector, which has a significant positive impact on energy density. Stable specific capacities of the CF/CNF negative electrode of 267 mAh g(-1) at 0.1 C and 150 mAh g(-1) at 1 C are demonstrated. The LFP/CNF with CF/CNF, as the current collector positive electrode (LFP-CF), exhibited a good rate performance with a capacity of -150 mAh g(-1) at 0.1 C and 133 mAh g(-1) at 1 C. The polarization of the LFP-CF electrode was similar to that of a commercial Quallion LFP electrode, while much lower compared to a flexible LFP/CNF electrode with Al foil as the current collector. This is ascribed to good contact between the CF and the active material.

  • 40.
    Martín-Yerga, Daniel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Electrochemical Detection and Characterization of Nanoparticles with Printed Devices2019In: Biosensors, ISSN 2079-6374, Vol. 9, no 2, article id 47Article, review/survey (Refereed)
    Abstract [en]

    Innovative methods to achieve the user-friendly, quick, and highly sensitive detection of nanomaterials are urgently needed. Nanomaterials have increased importance in commercial products, and there are concerns about the potential risk that they entail for the environment. In addition, detection of nanomaterials can be a highly valuable tool in many applications, such as biosensing. Electrochemical methods using disposable, low-cost, printed electrodes provide excellent analytical performance for the detection of a wide set of nanomaterials. In this review, the foundations and latest advances of several electrochemical strategies for the detection of nanoparticles using cost-effective printed devices are introduced. These strategies will equip the experimentalist with an extensive toolbox for the detection of nanoparticles of different chemical nature and possible applications ranging from quality control to environmental analysis and biosensing.

  • 41.
    Martín-Yerga, Daniel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Henriksson, Gunnar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Effects of Incorporated Iron or Cobalt on the Ethanol Oxidation Activity of Nickel (Oxy)Hydroxides in Alkaline Media2019In: Electrocatalysis, ISSN 1868-2529, E-ISSN 1868-5994Article in journal (Refereed)
    Abstract [en]

    Nickel (oxy)hydroxides (NiOxHy) are promising cost-effective materials that exhibit a fair catalytic activity for the ethanol oxidation reaction (EOR) and could be used for sustainable energy conversion. Doping the NiOxHy structure with other metals could lead to enhanced catalytic properties but more research needs to be done to understand the role of the doping metal on the EOR. We prepared NiOxHy films doped with Fe or Co with different metallic ratios by electrodeposition and evaluated the EOR. We found a positive and negative effect on the catalytic activity after the incorporation of Co and Fe, respectively. Our results suggest that Ni atoms are the active sites for the EOR since Tafel slopes were similar on the binary and pristine nickel (oxy)hydroxides and that the formal potential of the Ni(II)/Ni(III) redox couple is a good descriptor for the EOR activity. This work also highlights the importance of controlled metal doping on catalysts and may help in the design and development of improved materials for the EOR.

  • 42.
    Martín-Yerga, Daniel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. DropSens, Soc Limitada, Edificio CEEI,Parque Tecnol Asturias, Llanera 33428, Asturias, Spain.
    Perez-Junquera, Alejandro
    DropSens, Soc Limitada, Edificio CEEI,Parque Tecnol Asturias, Llanera 33428, Asturias, Spain..
    Begona Gonzalez-Garcia, Maria
    DropSens, Soc Limitada, Edificio CEEI,Parque Tecnol Asturias, Llanera 33428, Asturias, Spain..
    Hernandez-Santos, David
    DropSens, Soc Limitada, Edificio CEEI,Parque Tecnol Asturias, Llanera 33428, Asturias, Spain..
    Fanjul-Bolado, Pablo
    DropSens, Soc Limitada, Edificio CEEI,Parque Tecnol Asturias, Llanera 33428, Asturias, Spain..
    In Situ Spectroelectrochemical Monitoring of Dye Bleaching after Electrogeneration of Chlorine-Based Species: Application to Chloride Detection2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 12, p. 7442-7449Article in journal (Refereed)
    Abstract [en]

    Spectroelectrochemical techniques are becoming increasingly versatile tools to solve a diverse range of analytical problems. Herein, the use of in situ real-time luminescence spectroelectrochemistry to quantify chloride ions is demonstrated. Utilizing the bleaching effect of chlorine-based electrogenerated products after chloride oxidation, it is shown that the fluorescence of the rhodamine 6G dye decreases proportionally to the initial chloride concentration in solution. A strong decrease of fluorescence is observed in acidic media compared to a lower decrease in alkaline media, which suggests that Cl-2, favorably generated at low pH, could be the main species responsible for the fluorescence loss. This fact is corroborated with chronoamperometric measurements where the complete loss of fluorescence for the bulk solution is achieved. A fast mass transfer is needed to explain this behavior, in agreement with the generation of gaseous species such as Cl-2. Chloride detection was performed in artificial sweat samples in less than 30 s with great accuracy. This electrochemical/optical combined approach allows us to quantify species that are difficult to measure by electrochemistry due to the inadequate resolution of their redox processes or being without significant optical properties.

  • 43.
    Martín-Yerga, Daniel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. DropSens S.L., Edificio CEEI, Parque Tecnológico de Asturias, Llanera, Spain.
    Pérez-Junquera, A.
    González-García, M. B.
    Hernández-Santos, D.
    Fanjul-Bolado, P.
    Towards single-molecule: In situ electrochemical SERS detection with disposable substrates2018In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 45, p. 5748-5751Article in journal (Refereed)
    Abstract [en]

    Dynamic time-resolved Raman spectroelectrochemistry demonstrates the strong influence of nanostructuring and surface charge of in situ activated disposable substrates for SERS detection. Under specific conditions, a large enhancement factor and estimated calculations agree with the feasible detection of only a few molecules, approaching the limit of single-entity detection.

  • 44. Mesfun, S.
    et al.
    Lundgren, J.
    Toffolo, A.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Integration of an electrolysis unit for producer gas conditioning in a bio-synthetic natural gas plant2019In: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994, Vol. 141, no 1, article id 012002Article in journal (Refereed)
    Abstract [en]

    Producer gas from biomass gasification contains impurities like tars, particles, alkali salts, and sulfur/nitrogen compounds. As a result, a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into synthetic natural gas (SNG). A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of syngas produced. Internal rate of return (IRR) is evaluated as an economic indicator of the processes considered. Results indicate that, depending on process configuration, the production of SNG can be boosted by approximately 50-60% without the need of an additional carbon source, i.e., for the same biomass input as in standalone operation of the GoBi-Gas plant.

  • 45. Mesfun, Sennai
    et al.
    Lundgren, Joakim
    Toffolo, Andrea
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Integration of an electrolysis unit for producer gas conditioning in a bio-SNG plant2017In: 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017, 2017Conference paper (Refereed)
    Abstract [en]

    Producer gas from biomass gasification contains impurities like tars, particles, alkali salts and sulfur/nitrogen compounds. As a result a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into SNG. A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of tailored syngas produced. Investment opportunity is evaluated as an economic indicator of the processes considered. Results indicate that the production of SNG can be boosted by approximately 50% without the need of an additional carbon source, i.e. for the same biomass input as in standalone operation of the GoBiGas plant.

  • 46. Mikkonen, Saara
    et al.
    Ekström, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. COMSOL AB, Sweden.
    Thormann, Wolfgang
    High-resolution dynamic computer simulation of electrophoresis using a multiphysics software platform2018In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1532, p. 216-222Article in journal (Refereed)
    Abstract [en]

    The modeling and simulation software COMSOL Multiphysics (R) was recently extended with an electrophoretic transport interface. Its performance was investigated by comparison to results obtained using the 1D dynamic electrophoresis simulators GENTRANS and SIMUL5. Simulations of zone electrophoresis, isotachophoresis, isoelectric focusing and of an oscillating electrolyte system were performed. Smooth profiles were essentially identical indicating that the COMSOL electrophoretic transport interface is able to reproduce results of the 1D simulators. Differences in the way the respective numerical schemes handle steep concentration gradients and associated instabilities were observed. The COMSOL electrophoretic transport interface is expected to be useful as a general model for simulations in 1D, 2D or 3D geometries, as well as for simulations combining electrophoresis with other physical phenomena.

  • 47.
    Mussa, Abdilbari
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH The Royal Institute of Technology.
    Fast charging effects on ageing for energy-optimized automotive NMC/graphite prismatic lithium-ion cells.Manuscript (preprint) (Other academic)
  • 48.
    Mussa, Abdilbari
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH The Royal Institute of Technology.
    Inhomogeneous active layer contact loss in a cycled prismatic lithium-ion cell caused by the jelly-roll curvature.Manuscript (preprint) (Other academic)
  • 49.
    Mussa, Abdilbari
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. KTH The Royal Institute of Technology.
    Lithium-ion battery performance and ageing under uneven temperature distribution.Manuscript (preprint) (Other academic)
  • 50.
    Mussa, Abdilbari
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Liivat, Anti
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Marzano, Fernanda
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden.;Scania CV AB, SE-15187 Sodertalje, Sweden..
    Klett, Matilda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Scania CV AB, SE-15187 Sodertalje, Sweden.
    Philippe, Bertrand
    Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, S-75120 Uppsala, Sweden..
    Tengstedt, Carl
    Scania CV AB, SE-15187 Sodertalje, Sweden..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Edstrom, Kristina
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Lindström, Rakel Wreland
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Svens, Pontus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. Scania CV AB, SE-15187 Sodertalje, Sweden.
    Fast-charging effects on ageing for energy-optimized automotive LiNi1/3Mn1/3Co1/3O2/graphite prismatic lithium-ion cells2019In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 422, p. 175-184Article in journal (Refereed)
    Abstract [en]

    The reactions in energy-optimized 25 Ah prismatic NMC/graphite lithium-ion cell, as a function of fast charging (1C-4C), are more complex than earlier described. There are no clear charging rate dependent trends but rather different mechanisms dominating at the different charging rates. Ageing processes are faster at 3 and 4C charging. Cycling with 3C-charging results in accelerated lithium plating but the 4C-charging results in extensive gas evolution that contribute significantly to the large cell impedance rise. Graphite exfoliation and accelerated lithium inventory loss point to the graphite electrode as the source of the gas evolution. The results are based on careful post-mortem analyses of electrodes using: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). SEM results show particle cracking independent of the charging rate used for the cycling. XPS and EIS generally indicate thicker surface film and larger impedance, respectively, towards the edge of the jellyrolls. For the intended application of a battery electric inner-city bus using this type of cell, charging rates of 3C and above are not feasible, considering battery lifetime. However, charging rates of 2C and below are too slow from the point of view of practical charging time.

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