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  • 1.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Semiconductor-ionic Materials for Low Temperature Solid Oxide Fuel Cells2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Solid oxide fuel cell (SOFC) is considered as an attractive candidate for energy conversion within the fuel cell (FC) family due to several advantages including environment friendly, use of non-noble materials and fuel flexibility. However, due to high working temperatures, conventional SOFC faces many challenges relating to high operational and capital costs besides the limited selection of the FC materials and their compatibility issues. Recent SOFC research is focused on how to reduce its operational temperature to 700 ºC or lower. Investigation of new electrolytes and electrode materials, which can perform well at low temperatures, is a comprehensive route to lowering the working temperature of SOFC. Meanwhile, semiconductor-ionic materials based on semiconductors (perovskite/composite) and ionic materials (e.g. ceria based ion conductors) have been identified as potential candidates to operate in low temperature range with adequate SOFC power outputs.

    This investigation focuses on the development of semiconductor-ionic materials for low temperature solid oxide fuel cell (SOFC) and electrolyte-layer free fuel cell (EFFC). The content of this work is divided into four parts:

    First part of the thesis consists of the work on conventional SOFC to build knowledge and bridge from conventional SOFC to the new EFFC. Novel composite electrode (semiconductor) materials are synthesized and studied using established electrochemical and analytical methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The phase structure, morphology and microstructure of the composite electrodes are studied using XRD and SEM, and the weight loss is determined using TGA. An electrical conductivity of up to 143 S/cm of as-prepared material is measured using DC 4 probe method at 550 ºC. An electrolyte, samarium doped ceria (SDC) is synthesized to fabricate a conventional three component SOFC device. The maximum power density of 325 mW/cm2 achieved from the conventional device at 550 ºC.

    In the second part of the thesis, semiconductor-ionic materials based on perovskite and composite materials are prepared for low temperature SOFC and EFFC devices. Semiconductor-ionic materials are prepared via nanocomposite approach based on two-phase semiconductor electrode and ionic electrolyte. This semiconductor-ionic functional component was shown to integrate all fuel cell components anode, electrolyte and cathode functions into a single component, i.e. “three in one”, resulting in enhanced catalytic activity and improved SOFC performance.

    The third part of the thesis addresses the development and optimization of the EFFC technologies by studying the Schottky junction mechanism in such semiconductor-ionic type devices. Perovskite and functional nanocomposites (semiconductor-ionic materials) are developed for EFFC devices. Materials characterizations are performed using a number of standard experimental and analytical techniques. Maximum power densities from 600 mW/cm2 up to 800 mW/cm2 have been achieved at 600 ºC.

    Fourth part of the thesis describes the theoretical simulation of EFFCs. In this work, an updated numerical model is applied in order to study the EFFC device, which introduces some modifications to the existing relations for traditional fuel cell models. The simulated V-I and P-I curves have been compared with experimental curves, and both types of curves show a good consistency.

  • 2.
    Afzal, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Wang, Baoyuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhang, Wei
    He, Yunjuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jayasuriya, Jeevan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Binzhu
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fabrication of novel electrolyte-layer free fuel cell with semi-ionic conductor (Ba0.5Sr0.5Co0.8Fe0.2O3-delta- Sm0.2Ce0.8O1.9) and Schottky barrier2016In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 328, p. 136-142Article in journal (Refereed)
    Abstract [en]

    Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) is synthesized via a chemical co-precipitation technique for a low temperature solid oxide fuel cell (LTSOFC) (300-600 degrees C) and electrolyte-layer free fuel cell (EFFC) in a comprehensive study. The EFFC with a homogeneous mixture of samarium doped ceria (SDC): BSCF (60%:40% by weight) which is rather similar to the cathode (SDC: BSCF in 50%:50% by weight) used for a three layer SOFC demonstrates peak power densities up to 655 mW/cm(2), while a three layer (anode/ electrolyte/cathode) SOFC has reached only 425 mW/cm(2) at 550 degrees C. Chemical phase, crystal structure and morphology of the as-prepared sample are characterized by X-ray diffraction and field emission scanning electron microscopy coupled with energy dispersive spectroscopy. The electrochemical performances of 3-layer SOFC and EFFC are studied by electrochemical impedance spectroscopy (EIS). As-prepared BSCF has exhibited a maximum conductivity above 300 S/cm at 550 degrees C. High performance of the EFFC device corresponds to a balanced combination between ionic and electronic (holes) conduction characteristic. The Schottky barrier prevents the EFFC from the electronic short circuiting problem which also enhances power output. The results provide a new way to produce highly effective cathode materials for LTSOFC and semiconductor designs for EFFC functions using a semiconducting-ionic material.

  • 3.
    Ali, Amjad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Shehzad Bashir, F.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Rafique, A.
    Kaleem Ullah, M.
    Alvi, F.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Ghauri, M.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Electrochemical study of composite materials for coal-based direct carbon fuel cell2018In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 43, no 28, p. 12900-12908Article in journal (Refereed)
    Abstract [en]

    The efficient conversion of solid carbon fuels into energy by reducing the emission of harmful gases is important for clean environment. In this regards, direct carbon fuel cell (DCFC) is a system that converts solid carbon directly into electrical energy with high thermodynamic efficiency (100%), system efficiency of 80% and half emission of gases compared to conventional coal power plants. This can generate electricity from any carbonaceous fuel such as charcoal, carbon black, carbon fiber, graphite, lignite, bituminous coal and waste materials. In this paper, ternary carbonate-samarium doped ceria (LNK-SDC) electrolyte has been synthesized via co-precipitation technique, while LiNiCuZnFeO (LNCZFO) electrode has been prepared using solid state reaction method. Due to significant ionic conductivity of electrolyte LNK-SDC, it is used in DCFC. Three types of solid carbon (lignite, bituminous, sub-bituminous) are used as fuel to generate power. The X-ray diffraction confirmed the cubic crystalline structure of samarium doped ceria, whereas XRD pattern of LNCZFO showed its composite structure. The proximate and ultimate coal analysis showed that fuel (carbon) with higher carbon content and lower ash content was promising fuel for DCFC. The measured ionic conductivity of LNK-SDC is 0.0998 Scm−1 and electronic conductivity of LNCZFO is 10.1 Scm−1 at 700 °C, respectively. A maximum power density of 58 mWcm−2 is obtained using sub-bituminous fuel.

  • 4. Dong, Wenjing
    et al.
    Yaqub, Azra
    Janjua, Naveed K.
    Raza, Rizwan
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei, China.
    All in One Multifunctional Perovskite Material for Next Generation SOFC2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 193, p. 225-230Article in journal (Refereed)
    Abstract [en]

    Multifunctional roles of La0.2Sr0.25Ca0.45TiO3 (LSCT) perovskite material as anode, cathode, and electrolyte for low temperature solid oxide fuel cell (LT-SOFC) are discovered for the first time, and have been investigated via electrochemical impedance spectroscopy (EIS) and fuel cell (FC) measurements. LSCT resistance decreases prominently in FC environment as shown in this study. An improved performance was observed by compositing LSCT with samaria doped ceria (SDC) at 550 degrees C when the FC power density increased from tens of mW cm(-2) for the pure LSCT system up to hundreds of mW cm(-2). The improved conductivity of LSCT-SDC composite is highlighted. The multifunctionality of LSCT as cathode, anode and electrolyte could be attributed to different conducting behavior at high and low oxygen partial pressures and ionic conduction at intermediate oxygen partial pressures. These new discoveries not only indicate great potential for exploring multifunctional perovskites for the next generation SOFC, but also deepen SOFC science and develop new technologies.

  • 5. Fan, L.
    et al.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    He, C.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei University, China.
    Nanocomposites for "nano green energy" applications2017In: Bioenergy Systems for the Future: Prospects for Biofuels and Biohydrogen, Elsevier, 2017, p. 421-449Chapter in book (Refereed)
    Abstract [en]

    The efficient conversion of fuel's chemical energy into electricity in solid oxide fuel cell (SOFC), one of the promising candidates to replace the current combustion process, requires highly active cell components for quick charge transfer and reaction kinetics in the current low-temperature range. Operation at low temperatures enables the deployment of nanostructured materials, while the nanostructured cell components with improved electric properties further assist the reduction of the temperature for given power output. One of the major issues of the single-phase nanoparticle is its aggregation properties under harsh fuel-cell condition, which could be overcome or alleviated by the advanced approaches. Nanocomposite approach not only addresses the instability and some intrinsic issues with the single-phase materials but also brings the interesting synergetic electric properties with multifunctionality. We summarize the research activities in a range of nanocomposite materials in SOFCs in finding the positive roles to improve the cell components (anode, electrolyte, and cathode) electrochemical performances and cell efficiency for green energy applications.

  • 6.
    Fan, Liangdong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Tech-nology, Hubei University, Wuhan, China .
    Afzal, Mohammed
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Tech-nology, Hubei University, Wuhan, China .
    Electrolysis study of ceria-carbonate composite for effective H2 production2013In: EFC 2013 - Proceedings of the 5th European Fuel Cell Piero Lunghi Conference, 2013, p. 79-80Conference paper (Refereed)
    Abstract [en]

    The hybrid ionic conduction of ceria-carbonate composite is an interesting field that has attracted plenty attention in the past decade. However, it has not reached universal agreement among the researcher. Novel characterization method is still needed to reveal this complex system and benefit the future advanced materials design and development. In this work, the electrolysis operation is employed to investigate the possible ionic conduction behavior of ceria-carbonate. The other goal is to optimize the processing technology to maximum the kinetics rate for efficient hydrogen production. An impressive current density of 1.2 A cm-2 has been achieved at 600 °C under voltage of 1.6 V at the absolute humidity of 3% and oxygen ionic operational mode.

  • 7.
    Fan, Liangdong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Effective hydrogen production by high temperature electrolysis with ceria-carbonate compositeManuscript (preprint) (Other academic)
    Abstract [en]

    The high temperature electrolysis potentially offers an effective approach for large-scale and high purity hydrogen production. Besides, the research on the hybrid oxygen ion/proton conductive behavior is a hot field in the ceria-based composite field. In this present study, single cell assembled by SDC-carbonate electrolyte and Ni-based electrode was fabricated and operated in ceramic electrolysis cells (CECs) model. The effect of the relative humidity and temperature on the electrochemical performance was investigated by electrochemical impedance spectra (EIS) and polarization curves. Under an applied electrolysis voltage of 1.6 V, the maximum consumed current density is 1.2 Acm-2 in oxygen ionic conduction mode. The electrochemical performance in proton conduction mode is comparable to the oxygen ion conduction mode. The results here again demonstrate the hybrid ionic conduction of ceria-carbonate composite, and provide a promising materials system for high efficient hydrogen production.

  • 8.
    He, Yunjuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Faculty of Computer and Information, Hubei University, Wuhan, Hubei, China.
    Fan, Liangdong
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Faculty of Computer and Information, Hubei University, Wuhan, Hubei, China.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Singh, Manish
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhang, Wei
    Zhao, Yufeng
    Li, Junjiao
    Zhu, Bin
    Faculty of Computer and Information, Hubei University, Wuhan, Hubei, China.
    Cobalt oxides coated commercial Ba0.5Sr0.5Co0.8Fe0.2O3-delta as high performance cathode for low-temperature SOFCs2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 191, p. 223-229Article in journal (Refereed)
    Abstract [en]

    In order to improve the catalytic activity of commercial Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) for low-temperature solid oxide fuel cells (LTSOFC) (300-600 degrees C), CoOx has been used to modify the commercial BSCF through a solution coating approach. Phase and morphology of samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectrometry (EDS), respectively. BSCF with 10 wt% CoOx exhibited an improved conductivity of 44 S/cm, and achieved a peak power density of 463 mW/cm(2) at 550 degrees C for LTSOFC, which is a 100% enhancement than that with the BSCF cathode. The cathode oxygen reduction reaction (ORR) promoted by CoOx and enhanced device performance mechanism have been proposed. This work provides a new way for the exploitation of high effective cathode materials for LTSOFCs.

  • 9. Hu, H.
    et al.
    Lin, Q.
    Muhammad, Afzal J.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Electrochemical study of lithiated transition metal oxide composite for single layer fuel cell2015In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 286, p. 388-393Article in journal (Refereed)
    Abstract [en]

    This study analyzed the effect of various semiconductors of transition metal oxides in modified lithiated NiO on the electrochemical performance of a single layer fuel cell (SLFC). A typical ionic conductor Ce0.8Sm0.2O2-δ (SDC) and three types of semiconductors Li0.3Ni0.6Cu0.07Sr0.03O2-δ (LNCuS), Li0.3Ni0.6Mn0.07Sr0.03O2-δ (LNMnS) and Li0.3Ni0.6Co0.07Sr0.03O2-δ (LNCoS), were the fundamental components of the SLFCs. The components were characterized by using X-ray diffraction (XRD), a scanning electron microscope (SEM), and an energy-dispersive X-ray spectrometer (EDS). The stability of the synthesized materials was evaluated using thermal gravity analysis (TGA). The ohmic resistances at 500 °C were 0.36, 0.48 and 0.58 Ω cm2 for 6SDC-4LNMnS, 6SDC-4LNCoS and 6SDC-4LNCuS, respectively. Among the three SLFCs, the single cell with 6SDC-4LNMnS achieves the highest power density (422 mW cm-2) but the lowest temperature stability, while the single cell with 6SDC-4LNCuS achieved the lowest power density (331 mW cm-2) but the highest temperature stability during the operation temperature.

  • 10. Hu, Huiqing
    et al.
    Lin, Qizhao
    Zhu, Zhigang
    Liu, Xiangrong
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    He, Yunjuan
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Univ, Fac Phys & Elect Technol, Hubei Collaborat Innovat Ctr Adv Mat, Wuhan 430062, Hubei, Peoples R China.
    Effects of composition on the electrochemical property and cell performance of single layer fuel cell2015In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 275, p. 476-482Article in journal (Refereed)
    Abstract [en]

    In this study, the enhanced electrochemical performance of single layer fuel cells (SLFCs) based upon mixed ion and electron conductors is analyzed as a function of composition. We synthesize a series of Ce0.8Sm0.2O2-delta-Li0.3Ni0.6Cu0.07Sr0.03O2-delta (SDC-LNCS) with different weight ratios. The microstructure and morphology of the composite materials are characterized through X-ray diffraction (XRD), transmission electron microscope (TEM), and energy-dispersive X-ray spectrometer (EDS). Stability of the synthesized samples is evaluated by thermal gravity analysis (TGA). The SLFC with 6SDC-4LNCS exhibits a uniform distribution of the two compositions as well as demonstrates the highest power density of 312 mW cm-2 at 550 mu C. The performance is correlated to the balance of the conduction properties (ionic and electronic) of the functional SLFC layer. The results are a critical contribution to further development of this new energy transfer device.

  • 11.
    Liu, Yanyan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Meng, Yuanjing
    Zhang, Wei
    Wang, Baoyuan
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Xia, Chen
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, PR China.
    Industrial grade rare-earth triple-doped ceria applied for advanced low-temperature electrolyte layer-free fuel cells2017In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 42, no 34, p. 22273-22279Article in journal (Refereed)
    Abstract [en]

    In this study, the mixed electron-ion conductive nanocomposite of the industrial-grade rare-earth material (Le(3+), Pr3+ and Nd3+ triple-doped ceria oxide, noted as LCPN) and commercial p-type semiconductor Ni0.8Co0.15Al0.05Li-oxide (hereafter referred to as NCAL) were studied and evaluated as a functional semiconductor-ionic conductor layer for the advanced low temperature solid oxide fuel cells (LT-SOFCs) in an electrolyte layer-free fuel cells (EFFCs) configuration. The enhanced electrochemical performance of the EFFCs were analyzed based on the different semiconductor-ionic compositions with various weight ratios of LCPN and NCAL. The morphology and microstructure of the raw material, as prepared LCPN as well the commercial NCAL were investigated and characterized by Xray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometer (EDS), respectively. The EFFC performances and electrochemical properties using the LCPN-NCAL layer with different weight ratios were systematically investigated. The optimal composition for the EFFC performance with 70 wt% LCPN and 30 wt% NCAL displayed a maximum power density of 1187 mW cm(-2) at 550 degrees C with an open circuit voltage (OCV) of 1.07 V. It has been found that the well-balanced electron and ion conductive phases contributed to the good fuel cell performances. This work further promotes the development of the industrial-grade rare-earth materials applying for the LTSOFC technology. It also provides an approach to utilize the natural source into the energy field.

  • 12. Lu, Yuzheng
    et al.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Univ, Peoples R China.
    Wang, Baoyuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei Univ, Peoples R China.
    Wang, Jun
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Nanotechnology Based Green Energy Conversion Devices with Multifunctional Materials at Low Temperatures2017In: RECENT PATENTS ON NANOTECHNOLOGY, ISSN 1872-2105, Vol. 11, no 2, p. 85-92Article, review/survey (Refereed)
    Abstract [en]

    Background: Nanocomposites (integrating the nano and composite technologies) for advanced fuel cells (NANOCOFC) demonstrate the great potential to reduce the operational temperature of solid oxide fuel cell (SOFC) significantly in the low temperature (LT) range 300-600 degrees C. NANOCOFC has offered the development of multi-functional materials composed of semiconductor and ionic materials to meet the requirements of low temperature solid oxide fuel cell (LTSOFC) and green energy conversion devices with their unique mechanisms. Description: This work reviews the recent developments relevant to the devices and the patents in LTSOFCs from nanotechnology perspectives that reports advances including fabrication methods, material compositions, characterization techniques and cell performances. Conclusion: Finally, the future scope of LTSOFC with nanotechnology and the practical applications are also discussed.

  • 13.
    Mi, Youquan
    et al.
    China Univ Geosci, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Mat, Wuhan 430074, Hubei, Peoples R China..
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. China Univ Geosci, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Mat, Wuhan 430074, Hubei, Peoples R China.
    Zhu, Bin
    China Univ Geosci, Fac Phys & Elect Sci, Hubei Collaborat Innovat Ctr Adv Mat, Wuhan 430074, Hubei, Peoples R China.;Loughborough Univ Technol, Dept Aeronaut & Automot Engn, Fac Mat Sci & Chem, Loughborough LE11 3TU, Leics, England..
    Raza, Rizwan
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan..
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Riess, Ilan
    Technion Israel Inst Technol, Dept Phys, IL-3200003 Haifa, Israel..
    Experimental and physical approaches on a novel semiconducting-ionic membrane fuel cell2018In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 43, no 28, p. 12756-12764Article in journal (Refereed)
    Abstract [en]

    Semiconducting-ionic membranes (SIMs) have exhibited significant superiority to replace the conventional ionic electrolytes in solid oxide fuel cells (SOFCs). One interesting phenomenon is that the SIMs can successfully avoid the underlying short-circuiting issue and power losses while bringing significantly enhanced power output. It is crucial to understand the physics in such devices as they show distinct electrochemical processes with conventional fuel cells. We first presented experimental studies of a SIM fuel cell based on a composite of semiconductor LiCo0.8Fe0.2O2 (LCF) and ionic conductor Sm-doped CeO2 (SDC), which achieved a remarkable power density of 1150 mW cm(-2) at 550 degrees C along with a high open circuit voltage (OCV) of 1.04 V. Then, for the first time we used a physical model via combining a semiconductor-ionic contact junction with a rectifying layer which blocks the electron leakage to describe such unique SIM device and excellent performance. Current and power are the most important characteristics for the device, by introducing the rectifying layer we described the SIM physical nature and new device process. This work presented a new view on advanced SIM SOFC science and technology from physics.

  • 14. Qiao, Z.
    et al.
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, Wuhan, Hubei, China.
    Cai, Y.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Wang, H.
    Qiao, J.
    Zhu, B.
    Electrochemical and electrical properties of doped CeO2-ZnO composite for low-temperature solid oxide fuel cell applications2018In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 392, p. 33-40Article in journal (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) as a multi-function semiconductor is widely known for photocatalysis and electronic applications but exceptionally new in Solid State Ionics. In this study, a new semiconducting-ionic conductor is reported for solid oxide fuel cells (SOFCs) applications by composing ZnO with an ionic conductor La/Pr co-doped CeO2 (LCP) in various mass ratios. The prepared composites acting as membranes are sandwiched between two Ni0.8Co0.15Al0.05LiO2-δ (NCAL) electrodes to construct fuel cells. A remarkable maximum power output of 1055 mW cm−2 is attained along with a high open circuit voltage (OCV) of 1.04 V at 550 °C by the fuel cell using an optimal composition of 7LCP-3ZnO. The electrical properties of the composites as a function of LCP/ZnO ratio are studied through EIS measurements and polarization curves. It has been found that the composite of 7LCP-3ZnO exhibits a higher ionic conductivity than other composite samples at 475–550 °C, while possessing both high electronic and ionic conduction. Our further investigation also verifies the appreciable protonic conduction in LCP-ZnO, suggesting that the developed composite is a triple O2-/H+/e− conducting material. Additionally, rectification characteristic of the best-performance cell is also measured to interpret the high OCVs and power outputs of LCP-ZnO fuel cells.

  • 15.
    Raza, Rizwan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. COMSATS Institute of Information Technology, Pakistan.
    Ullah, M. K.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Rafique, A.
    Ali, A.
    Arshad, S.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei University, China.
    Low-temperature solid oxide fuel cells with bioalcohol fuels2017In: Bioenergy Systems for the Future: Prospects for Biofuels and Biohydrogen, Elsevier, 2017, p. 521-539Chapter in book (Refereed)
    Abstract [en]

    Energy and environmental issues become key factors for sustainable development of society and national economy. Sustainable energy targeting opportunities for economic friendly growth of a country are commonly recognized. The growing interest is focused on the renewable energy resources because of the global energy demands increasing day by day. To meet the demands, an extensive research is aimed to develop sustainable energy devices such as solar cells, rechargeable batteries, and fuel cells. In recent years, solid oxide fuel cell (SOFC) among fuel-cell types has got more attention especially due to its fuel flexibility (e.g., different hydrocarbons, alcohols, and gasoline/diesel), high efficiency, and low emission. Thus, LTSOFC fed by direct bioethanol is receiving considerable attention as a clean, highly efficient for the production of both electricity and high-grade waste heat. These multifuel advantages provide the opportunities to develop an advanced SOFC system especially bioalcohol SOFC systems. This is a very dynamic area for SOFC applications with a promising future. It may create great energy savings and pollution reductions, if the bioalcohol fuel-based-technologies in these applications come into practical use.This chapter is focused on the development of LTSOFC operated by direct bioalcohol (bioethanol and biomethanol) for sustainable development. The content of this chapter is divided into three parts: (i) development of materials, (ii) characterization and analysis, (iii) demonstration of the nanocomposite materials in a bioalcohol FC, and (iv) case studies. Such bioalcohol FC research and development can enhance the use of sustainable/renewable energy for the society, and results achieved for applications have great potential to revolutionize the energy technology in an environmentally friendly and sustainable way.

  • 16.
    Wang, Baoyuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Cai, Yixiao
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Uppsala University, Sweden.
    Dong, Wenjing
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Zhang, Wei
    Liu, Yanyan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Wang, Hao
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Photovoltaic properties of LixCo3-xO4/TiO2 heterojunction solar cells with high open-circuit voltage2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 157, p. 126-133Article in journal (Refereed)
    Abstract [en]

    All-oxide solar cells are presently attracting extensive research interest due to their excellent stability, low-cost and non-toxicity. However, the band gap of metal oxides is lack of effective optimization and results in poor photovoltaic performance, thus hindering their practical applications. In this work, Co3O4 was investigated for application as a photo-absorber in all-oxide solar cells, and its band gap was optimized by introducing Li dopant into the spinel structure. LixCo3-xO4 nanoparticles, prepared via the hydrothermal method, were homogenously coated onto TiO2 mesoporous films, which were then used to fabricate planar heterojunction TiO2/LixCo3-xO4 solar cells (SCs). The effects of Li-doping on the heterojunction solar cell performance were further investigated. The findings revealed that the incorporation of Li ions into Co3O4 led to a significant enhancement in short-circuit current density (J(sc)). Remarkably, a high open-circuit voltage (V-oc) of 0.70 V was also achieved. Besides, reasons for the enhanced cell performance are the narrower band gap, reduced photogenerated carrier recombination and the more favorable energy band structure as compared with SCs assembled from pure Co3O4.

  • 17. Wang, Baoyuan
    et al.
    Cai, Yixiao
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Kim, Jung-Sik
    Liu, Yanyan
    Dong, Wenjing
    Wang, Hao
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Li, Junjiao
    Raza, Rizwan
    Zhu, Bin
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Semiconductor-ionic Membrane of LaSrCoFe-oxide-doped Ceria Solid Oxide Fuel Cells2017In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 248, p. 496-504Article in journal (Refereed)
    Abstract [en]

    A novel semiconductor-ionic La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-Sm/Ca co-doped CeO2 (SCDC) nanocomposite has been developed as a membrane, which is sandwiched between two layers of Ni0.8Co0.15Al0.05Li-oxide (NCAL) to construct semiconductor-ion membrane fuel cell (SIMFC). Such a device presented an open circuit voltage (OCV) above 1.0 V and maximum power density of 814 mW cm(-2) at 550 degrees C, which is much higher than 0.84 V and 300 mW cm(-2) for the fuel cell using the SCDC membrane. Moreover, the SIMFC has a relatively promising long-term stability, the voltage can maintain at 0.966 V for 60 hours without degradation during the fuel cells operation and the open-circuit voltage (OCV) can return to 1.06 V after long-term fuel cell operation. The introduction of LSCF electronic conductor into the membrane did not cause any short circuit but brought significant enhancement of fuel cell performances. The Schottky junction is proposed to prevent the internal electrons passing thus avoiding the device short circuiting problem.

  • 18.
    Wang, Xunying
    et al.
    Hubei University Wuhan, China.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Deng, Hui
    Hubei University Wuhan, China.
    Dong, Wenjing
    Hubei University Wuhan, China.
    Wang, Baoyuan
    Hubei University Wuhan, China.
    Mi, Youquan
    Hubei University Wuhan, China.
    Xu, Zhaoyun
    Hubei University Wuhan, China.
    Zhang, Wei
    Hubei University Wuhan, China.
    Feng, Chu
    Hubei University Wuhan, China.
    Wang, Zhaoqing
    Hubei University Wuhan, China.
    Wu, Yan
    China University of Geosciences Wuhan, China.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    La0.1SrxCa0.9-xMnO3-δ -Sm0.2Ce0.8O1.9 composite material for novel low temperature solid oxide fuel cells2017In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 42, no 27, p. 17552-17558Article in journal (Refereed)
    Abstract [en]

    Lowering the operating temperature of the solid oxide fuel cells (SOFCs) is one of the world R&D tendencies. Exploring novel electrolytes possessing high ionic conductivity at low temperature becomes extremely important with the increasing demands of the energy conversion technologies. In this work, perovskite La0.1SrxCa0.9-xMnO3-δ (LSCM) materials were synthesized and composited with the ionic conductor Sm0.2Ce0.8O1.9 (SDC). The LSCM-SDC composite was sandwiched between two nickel foams coated with semiconductor

    Ni0.8Co0.15Al0.05LiO2- δ (NCAL) to form the fuel cell device. The strontium content in theLSCM and the ratios of LSCM to SDC in the LSCM-SDC composite have significant effects on the electrical properties and fuel cell performances. The best performance has been achieved from LSCM-SDC composite with a weight ratio of 2:3. The fuel cells showed OCV over 1.0 V and excellent maximum output power density of 800 mW/cm2 at 550 ºC. Device processes and ionic transport processes were also discussed.

  • 19.
    Xia, Chen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Cai, Y.
    Wang, Baoyuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhang, W.
    Soltaninazarlou, Aslan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Strategy towards cost-effective low-temperature solid oxide fuel cells: A mixed-conductive membrane comprised of natural minerals and perovskite oxide2017In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 342, p. 779-786Article in journal (Refereed)
    Abstract [en]

    Our previous work has revealed the feasibility of natural hematite as an electrolyte material for solid oxide fuel cells (SOFCs), tailoring SOFCs to be a more economically competitive energy conversion technology. In the present work, with the aim of exploring more practical uses of natural minerals, a novel composite hematite/LaCePrOx-La0.6Sr0.4Co0.2Fe0.8O3-δ (hematite/LCP-LSCF) has been developed from natural hematite ore, rare-earth mineral LaCePr-carbonate, and perovskite oxide LSCF as a functional membrane in SOFCs. The heterogeneity, nanostructure and mixed-conductive property of the composite were investigated. The results showed that the hematite/LCP-30 wt% LSCF composite possessed balanced ionic and electronic conductivities, with an ionic conductivity as high as 0.153 S cm−1 at 600 °C. The as-designed fuel cell using the hematite/LCP-LSCF membrane exhibited encouraging power outputs of 303 – 662 mW cm−2 at 500 – 600 °C. These findings show that the hematite/LCP-LSCF based fuel cell is a viable strategy for developing cost-effective and practical low-temperature SOFCs (LTSOFCs).

  • 20.
    Xia, Chen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Collaborative Innovation Center for Advanced Materials, Faculty of Physics and Electronic Technology, Hubei University, Wuhan, Hubei, China.
    Wang, Baoyuan
    Hubei Collaborative Innovation Center for Advanced Materials, Faculty of Physics and Electronic Technology, Hubei University, Wuhan, Hubei, China.
    Ma, Y.
    Cai, Y.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Liu, Y.
    He, Y.
    Zhang, W.
    Dong, W.
    Li, J.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Collaborative Innovation Center for Advanced Materials, Faculty of Physics and Electronic Technology, Hubei University, Wuhan, Hubei, China.
    Industrial-grade rare-earth and perovskite oxide for high-performance electrolyte layer-free fuel cell2016In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 307, p. 270-279Article in journal (Refereed)
    Abstract [en]

    In the present work, we report a composite of industrial-grade material LaCePr-oxide (LCP) and perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) for advanced electrolyte layer-free fuel cells (EFFCs). The microstructure, morphology, and electrical properties of the LCP, LSCF, and LCP-LSCF composite were investigated and characterized by XRD, SEM, EDS, TEM, and EIS. Various ratios of LCP to LSCF in the composite were modulated to achieve balanced ionic and electronic conductivities. Fuel cell with an optimum ratio of 60 wt% LCP to 40 wt% LSCF reached the highest open circuit voltage (OCV) at 1.01 V and a maximum power density of 745 mW cm-2 at 575°C, also displaying a good performance stability. The high performance is attributed to the interfacial mechanisms and electrode catalytic effects. The findings from the present study promote industrial-grade rare-earth oxide as a promising new material for innovative low temperature solid oxide fuel cell (LTSOFC) technology.

  • 21. Zhu, B.
    et al.
    Lund, P. D.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. COMSATS Institute of Information Technology, Pakistan .
    Ma, Y.
    Fan, L.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Patakangas, J.
    He, Y.
    Zhao, Y.
    Tan, W.
    Huang, Q. -A
    Zhang, J.
    Wang, H.
    Schottky junction effect on high performance fuel cells based on nanocomposite materials2015In: Advanced Energy Materials, ISSN 1614-6832, Vol. 5, no 8, article id 1401895Article in journal (Refereed)
    Abstract [en]

    A novel fuel cell device based on integrating the Schottky junction effect with the electrochemical principle is designed, constructed, and verified through experiments. It is found that the Schottky junction has a significant effect on the greatly enhanced device performance, and the fuel cell device incorporating the Schottky junction effect reaches a power output of 1000 mW cm-2 at 550 C.

  • 22.
    Zhu, Bin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei University, China.
    Fan, L.
    Deng, H.
    He, Y.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Dong, W.
    Yaqub, A.
    Janjua, N. K.
    LiNiFe-based layered structure oxide and composite for advanced single layer fuel cells2016In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 316, p. 37-43Article in journal (Refereed)
    Abstract [en]

    A layered structure metal oxide, LiNi0.1Fe0.90O2-δ (LNF), is explored for the advanced single layer fuel cells (SLFCs). The temperature dependent impedance profiles and concentration cells (hydrogen concentration, oxygen concentration, and H2/air atmospheres) tests prove LNF to be an intrinsically electronic conductor in air while mixed electronic and proton conductor in H2/air environment. SLFCs constructed by pure LNF materials show significant short circuiting reflected by a low device OCV and power output (175 mW cm-2 at 500°C) due to high intrinsic electronic conduction. The power output is improved up to 640 and 760 mW cm-2, respectively at 500 and 550°C by compositing LNF with ion conducting material, e.g., samarium doped ceria (SDC), to balance the electronic and ionic conductivity; both reached at 0.1 S cm-1 level. Such an SLFC gives super-performance and simplicity over the conventional 3-layer (anode, electrolyte and cathode) FCs, suggesting strong scientific and commercial impacts.

  • 23.
    Zhu, Bin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei, China.
    Huang, Yizhong
    Fan, L.
    Ma, Y.
    Wang, Baoyuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei, China.
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhang, B.
    Dong, W.
    Wang, H.
    Lund, P. D.
    Novel fuel cell with nanocomposite functional layer designed by perovskite solar cell principle2016In: Nano Energy, ISSN 2211-2855, Vol. 19, p. 156-164Article in journal (Refereed)
    Abstract [en]

    A novel fuel-to-electricity conversion technology resembling a fuel cell has been developed based on the perovskite solar cell principle using a perovskite, e.g. La0.6Sr0.4Co0.2Fe0.8O3-δ and an ionic nanocomposite material as a core functional layer, sandwiched between n- and p-conducting layers. The conversion process makes use of semiconductor energy bands and junctions properties. The physical properties of the junction and alignment of the semiconductor energy band allow for direct ion transport and prevent internal electronic short-circuiting, while at the same time avoiding losses at distinct electrolyte/electrode interfaces typical to conventional fuel cells. The new device achieved a stable power output of 1080mWcm-2 at 550°C in converting hydrogen fuel into electricity.

1 - 23 of 23
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