Porous nickel electrodes in water electrolysis 1. Electrode preparation and polarization studies in strong alkali

Replacement of “plate” electrodes in water electrolysis cells by porous nickel electrodes leads to many advantages resulting in reduced specific energy consumption for hydrogen production. Yet, the behaviour of porous electrodes in alkaline or acidic electrolysis has not been extensively studied; available data at temperatures above 70°C is negligible. This paper describes the techniques developed to prepare the porous electrodes, their physical characteristics and their performance in strong alkali as hydrogen and oxygen gas electrodes. Steady state cell polarization studies over a range of 100 to 10,000 ASM at different temperatures were carried out in 6N KOH solution for different electrode samples prepared by alloy electrodeposition and powder metallurgy methods. Electrodes prepared by these two methods were compared with respect to their electrochemical performance. The current carrying capacity at a given overvoltage was evaluated for different electrode thicknesses. These electrodes have been used successfully in test modules of bipolar filter press type construction for hydrogen production.