Electrochemical characteristics of the interface between the metal hydride electrode and electrolyte for an advanced nickel metal hydride battery

The characteristics of the negative electrode of a Ni/MH (metal hydride) battery are related to the charge transfer and mass transfer processes at the interface between the MH electrode and the electrolyte. With increasing number of charge/discharge cycles, the MH alloy powders micro-crack into particles that are several microns in diameter and this then influences the exchange current density. A polarization experiment was used to analyze the charge transfer and mass transfer processes. The exchange current densities of uncoated and Pd-coated Mm(0.95)Ti(0.05)N(3.85)Co(0.45)Mn(0.35)Al(0.35) alloy electrodes increase with increasing number of charge/discharge cycles before reaching a constant value after 20-30 cycles. (C) 1999 Elsevier Science S.A. All rights reserved.