Improved performance of solid-state metal hydride batteries using heteropolyacid hydrate as an electrolyte

In order to enhance the electrochemical performance of our solid-state metal hydride battery using an electrolyte of heteropolyacid hydrate, such as 12-molybdophosphoric acid hydrate (H3PMO12O40 . 20H(2)O), we tried to improve the total battery construction; the interface between electrode and electrolyte was increased and the electrolytic manganese dioxide was adapted as a positive electrode material instead of reagent grade manganese dioxide previously used. The resultant battery exhibited remarkably longer cycle He performance, higher discharge efficiency, and lower polarization than the previous one. The high rate charge-discharge characteristics was improved significantly by optimizing electrolyte content in the positive electrode; the battery was able to operate over 200 cycles at 10 mA g (alloy)(-1).