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 Mm0.95Ti0.05Ni3.85Co0.45Mn0.35Al0.35 alloy electrodes increase with increasing number of charge/discharge cycles before reaching a constant value after 20–30 cycles.