The electrochemical performance of Pd-coated metal hydride electrodes with different binding additives in alkaline solution

The performance characteristics of Pd-coated mischmetal-based alloy electrodes containing either copper powder or Teflonized carbon additives were evaluated in alkaline solution at 25 degrees C. The Pd coating was very effective for Increasing both the discharge capacity and rate capability and for decreasing the galvanostatic cycling time for activating the alloy electrodes. The best performances were attained with electrodes with 6 wt % Pd content. The electrodes with the Teflonized carbon additive also exhibited greater stability and longer cycle life than those with the copper additive. The improved performance of Pd-coated alloy electrodes over that of an uncoated alloy electrode can be attributed to the catalytic effect of Pd on the charge-transfer step at the electrode surface.