CALCULATION OF ELECTROCHEMICAL OVERPOTENTIAL AND CONCENTRATION OVERPOTENTIAL BASED ON CURVE OF ANODIC POLARIZATION IN HYDROGEN STORAGE ALLOY ELECTRODE
(Department of Materials Science and Engineering,Zhejiang University, Hangzhou 310027, P. R. China)
Abstract: It was investigated in detail how to calculate the electrochemical polarization overpotentialVe and concentration polarization overpotentialVcbased on anodic polarization curve in hydrogen storage alloys electrode. The results show that the experimental anodic polarization curve should be divided into three regions to discuss according to discharge current densityJd, namely,Jd<Jp,Jp<Jd<Jf, andJd>Jf. In different regions, the calculation forVeandVcshould use different formulas. When discharge current densityJdis smaller thanJp, the traditional equation used to calculate the electrochemical overpotential can’t be used, whenJdis betweenJpandJf, both equations used to calculate the electrochemical overpotential and concentration overpotential can be used, and whenJdis larger thanJf, because there exists absorption and adsorption of hydrogen, the traditional equation used to calculate concentration overpotential can’t be used in the system of
hydride electrodes.
hydride electrodes.
Key words: electrochemical overpotential concentration overpotential anodic polarization
hydrogen storage alloy
hydrogen storage alloy