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Title: Effect of cadmium on the nickel hydroxide alkaline electrode

Thesis/Dissertation ·
OSTI ID:6114481

The nickel hydroxide alkaline electrode, one of the electrodes found in Nickel-Cadmium, Nickel-Iron, Nickel-Zinc and Nickel-Hydrogen electrochemical cells has been the subject of numerous investigations. Impurities or additives to the electrode active material have been known to have an effect on its oxidation/reduction properties. As of this time little information is available on the effect of cadmium on the electrode characteristics. The effect of cadmium on the nickel hydroxide electrode mechanism was evaluated using Cyclic Linear Scan Voltammetry (LSV). This sensitive electrochemical technique has been utilized in the study of electrode mechanisms. The current-potential (i-E) curves produced during the oxidation/reduction process provide an insight as to whether the reaction is reversible, irreversible or quasi-reversible. It was found in this work to follow a quasi-reversible behavior. The nickel hydroxide was deposited on a high purity nickel wire electrochemically from a nickel nitrate solution under controlled conditions. The electrode performance was evaluated without cadmium and with three levels of cadmium hydroxide electrodeposited on the nickel hydroxide. Evaluation also was made at 20, 30 and 40/sup 0/C and in 1, 4 and 8 molal KOH concentrations. The results clearly indicated that cadmium had a greater stabilizing effect than the electrodes without cadmium. The potential and current characteristics of the electrodes without cadmium changed with scan number up to 100 scans and beyond. In addition, the changes reflected a more rapid degradation as temperature increased. The cadmium stabilized the potential and current even at a temperature of 40/sup 0/C. A coupled reaction mechanism involving an electrochemical charge transfer followed by a reversible chemical reaction (ErCr) is suggested, which meets the criteria for this mechanism.

OSTI ID:
6114481
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English