AC impedance of RE(NiCoMnTi)(5) alloy under different depth of discharge

Abstract

Electrochemical impedance spectra (EIS) of RE(NiCoMnTi)(5) alloys (RE = La, Ce, Pr, Nd) were measured and analyzed under different depths of discharge (DOD). The results reveal that at different phase areas, such as beta, alpha + beta and alpha, the alloy shows quite different characteristics in their discharge kinetics. At the same DOD of 50%, the surface hydrogen adsorbing resistance R-sf and Faraday resistance R-F of the four alloys represent an approximate linear relationship to their the maximum discharge capacity C-50,C- max and the high-rate-dischargeability kappa respectively, indicating the alloy with a higher R-sf and R-F will have a larger capacity and better dischargeability.