Change search
ReferencesLink to record
Permanent link

Direct link
Investigation of Electrochemical Behavior of Stimulation/Sensing Materials for Pacemaker Electrode Applications II: Conducting oxide electrodes
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.ORCID iD: 0000-0002-4431-0671
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.ORCID iD: 0000-0002-9453-1333
2005 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 152, no 7, J85-J92 p.Article in journal (Refereed) Published
Abstract [en]

The electrochemical behavior, interfacial properties, and stability of RuO2-, IrO2-, (Ru1-xMnx)O-2- and (Ir1-xMnx)O-2-coated electrodes for pacemaker applications were investigated in a phosphate buffered saline solution, by electrochemical impedance spectroscopy and cyclic voltammetry (CV). The psuedocapacitive properties of these conducting oxides and influence of coating roughness and porosity were examined, and accelerated aging of the electrode materials was simulated by fast sweep rate CV cycles between -3 to 1 V vs. Ag/AgCl. Changes in surface composition and structure due to the accelerated aging were investigated using X-ray photoelectron spectroscopy and scanning electron microscopy. The conducting oxides exhibit high interfacial capacitance. At high sweep rates, not all of total capacitance could be utilized due to voltage drop associated with resistance down the pores. Above a certain sweep rate, the charging/discharging mechanism changes from capacitive to resistive character. Showing the best performance among the investigated materials, the RuO2 exhibits capacitive characteristics at sweep rates up to 20 V/s and excellent stability under the accelerated aging. The IrO2 coating was not stable during the cycling. The mixed oxides experience limitations at high sweep rates due to the ohmic effects and some degradation due to the accelerated aging.

Place, publisher, year, edition, pages
2005. Vol. 152, no 7, J85-J92 p.
Keyword [en]
Aging of materials, Coatings, Cyclic voltammetry, Degradation, Electric conductivity, Electric potential, Electrochemistry, Porosity, Scanning electron microscopy, Spectroscopic analysis, X ray photoelectron spectroscopy
National Category
Physical Chemistry
URN: urn:nbn:se:kth:diva-5063DOI: 10.1149/1.1933372ISI: 000229859100072ScopusID: 2-s2.0-23744517091OAI: diva2:7746
QC 20100920Available from: 2005-04-25 Created: 2005-04-25 Last updated: 2010-09-20Bibliographically approved
In thesis
1. Investigation of electrochemical properties and performance of stimulation/sensing electrodes for pacemaker applications
Open this publication in new window or tab >>Investigation of electrochemical properties and performance of stimulation/sensing electrodes for pacemaker applications
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

People suffering from certain types of arrhythmia may benefit from the implantation of a cardiac pacemaker. Pacemakers artificially stimulate the heart by applying short electrical pulses to the cardiac tissue to restore and maintain a steady heart rhythm. By adjusting the pulse delivery rate the heart is stimulated to beat at desired pace. The stimulation pulses are transferred from the pacemaker to the heart via an electrode, which is implanted into the cardiac tissue. Additionally, the electrode must also sense the cardiac response and transfer those signals back to the electronics in the pacemaker for processing. The communication between the electrode and the tissue takes place on the electrode/electrolyte (tissue) interface. This interface serves as the contact point where the electronic current in the electrode is converted to ionic currents capable to operate in the body. The stimulation/sensing signals are transferred across the interface via three electrochemical mechanisms: i) non-faradaic charging/discharging of the electrochemical double layer, ii) reversible and iii) irreversible faradaic reactions. It is necessary to study the contribution of each mechanism to the total charge transferred to evaluate the pacing/sensing performance of the pacemaker electrode.

In this thesis, the electrochemical properties and performance of stimulation/sensing electrodes for pacemaker applications have been investigated by electrochemical impedance spectroscopy, cyclic voltammetry and transient electrochemical techniques. All measurements were performed in synthetic body fluid with buffer capacity. Complementary surface analysis was performed with scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy.

The results reveal different interfacial behaviour and stability for electrode materials such as Pt, TiN, porous carbon, conducting oxides (RuO2 and IrO2 and mixed oxides) and porous Nb2O5 oxide. The influence of the charge/discharge rate on the electrode characteristics also has been evaluated. Although the rough and porous electrodes provide a high interfacial capacitance, the maximum capacitance cannot be fully employed at high charge/discharge rates because only a small part of the effective surface area is accessible. The benefit of pseudo-capacitive material properties on charge delivery was observed. However, these materials suffer similar limitations at high charge/discharge rate and, hence, are only utilising the surface bound pseudo-capacitive sites. Porous Nb2O5 electrodes were investigated to study the performance of capacitor electrodes. These electrodes predominantly deliver the charge via reversible non-faradaic mechanisms and hence do not produce irreversible by-products. They can deliver very high potential pulses while maintaining high impedance and, thus, charge lost by faradaic currents are kept low. By producing Nb oxide by plasma electrolysis oxidation a porous surface structure is obtained which has the potential to provide a biocompatible interface for cell adherence and growth.

This thesis covers a multidisciplinary area. In an attempt to connect diverse fields, such as electrophysiology, materials science and electrochemistry, the first chapters have been attributed to explaining fundamental aspects of the respective fields. This thesis also reviews the current opinion of pacing and sensing theory, with special focus on some areas where detailed explanation is needed for the fundamental nature of electrostimulation/sensing.

Place, publisher, year, edition, pages
Stockholm: KTH, 2005. vii, 119 p.
Physical chemistry, pacemaker electrode, interfacial property, biomaterial, electrostimulation charge transfer mechanism, electrochemical impedance spectroscopy, transient processes, plasma electrolysis anodisation, porous niobium oxide, ruthenium oxide, nano-porous carbon, iridium oxide, titanium nitride, platinum, surface roughness, porous electrode, pacing impedance, electrode polarisation, Fysikalisk kemi
National Category
Physical Chemistry
urn:nbn:se:kth:diva-176 (URN)91-7283-994-5 (ISBN)
Public defence
2005-04-29, Kollegiesalen, Administrationsbyggnaden, Valhallavägen 79, Stockholm, 14:00 (English)
QC 20101014Available from: 2005-04-25 Created: 2005-04-25 Last updated: 2012-03-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Norlin, AnnaPan, JinshanLeygraf, Christopher
By organisation
Materials Science and Engineering
In the same journal
Journal of the Electrochemical Society
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 51 hits
ReferencesLink to record
Permanent link

Direct link