Effects of electrode thickness on power capability of a sintered-type nickel electrode

The performance capability of sintered-type nickel electrodes with thicknesses of up to 4.6 mm was studied in an Ni/H-2 cell. The utilization of active material at high rate discharge diminishes as the thickness of electrode increases. Full utilization at C rate discharge was obtained with electrodes with a thickness of 2.5 mm. A 1 mm thick electrode showed a well-defined discharge curve up to 20C rate discharge. Electrodes of up to 3.5 mm thickness showed sufficiently high rate capability for a geosynchronous earth orbit (GEO) application, while the maximum acceptable thickness for a low earth orbit (LEO) application is limited to a value below 2.5 mm. It appears that there is a limited amount of usable capacity at a given current density because of electrode polarization. The value of the current density appears to be independent of electrode thickness.