Capacity Retention Characteristics of Nickel/Metal Hydride Batteries with Polymer Hydrogel Electrolyte

Capacity retention characteristics of nickel/metal hydride (Ni/MH) batteries with polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and a 7.3 M KOH aqueous solution were investigated. The experimental Ni/MH cell with the polymer hydrogel electrolyte exhibited much better capacity retention than that with a 7.3 M KOH aqueous solution at 25°C. It was also found that the polymer hydrogel electrolyte suppressed both reversible and irreversible capacity losses. The effects were fairly remarkable at relatively high temperature, such as 55°C. These characteristics of the polymer hydrogel electrolyte can be significant advantages for use in the practical Ni/MH batteries.