The feasibility of using a rechargeable MnO2 cathode with a metal hydride anode

The feasibility of using a manganese dioxide cathode with a metal hydride a node is discussed. MnO2 cathodes doped with bismuth compounds were recharge able. The cathode material was prepared in its discharged state from MnO an d bismuth compounds, thus matching the metal hydride anode in terms of init ial state of charge, formation cycles and balance of self-discharge. It is believed that the presence of bismuth in the cathode prevents formation of spinel manganese oxide and lowers the activation energy (overpotential) for the second electron reduction and oxidation of MnO2. Hydrogen recombinatio n with MnO2 was also studied to enable balancing of the self discharge rate s of cathode and anode during storage.