EFFECTS OF FOREIGN IONS ON NICKEL HYDROXIDE AND CADMIUM ELECTRODES.
DEFENCE CHEMICAL BIOLOGICAL AND RADIATION LABS OTTAWA (ONTARIO)
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The bahavior of individual positive and negative electrodes of the sintered-plate nickel-cadmium battery system in the presence of foreign ions in KOH solutions was examined. Carbonate choke The variation of electrochemical capacity as a function of carbonate contamination of the electrolyte, temperature, and current density was measured for both positive and negative electrodes. The effect of carbonate on the negative cadmium electrode is much greater than on the positive. The general mechanism and the role of intermediate complexes are discussed. Nitrate shuttle Self-discharge occurs in cells containing nitrate, as a result of reduction of NO3- to NO2- at the cadmium electrode with subsequent reoxidation to NO3- at the nickel hydroxide electrode. Cations on the positive Addition of Li, Ag, Sb3, Al3, and As3 to the electrolyte had effects on capacity and on charge-retention of well-formed nickel hydroxide positive electrodes. Lithium promoted the highest average oxidation, particularly at high temperatures 55C. Arsenic was the best inhibitor of loss of charge. Possible mechanisms are discussed. Author