MATERIAL PROPERTIES AND PROCESSING IN THE PRODUCTION OF FUEL-CELL COMPONENTS .1. HYDROGEN ANODES FROM RANEY-NICKEL FOR LIGHTWEIGHT ALKALINE FUEL-CELLS

The production steps of Raney nickel based, PTFE bonded hydrogen anodes for alkaline fuel cells are examined. The Raney nickel catalyst has been made by leaching the nickel aluminium alloy and additional stabilization. The electrode is fabricated by mixing the catalyst with copper oxide for enhancing electronic conductivity and aqueous PTFE emulsion as a hydrophobic binder. Each process step, starting from the nickel aluminium alloy is described and the physical properties of catalyst and electrode are evaluated. At an overpotential of 100 mV the optimized hydrogen anode exhibits at negligable excess hydrogen pressure (1·02bars) a current density of nearly 400 mA cm-2 at 80°C in 30 wt% KOH. Long term performance test shows that electrode overpotential of more than 60 mV should be avoided. A life time of 5000 hrs at 50°C and a current density of 100 mA cm-2 has been proven. © 1990 Chapman and Hall Ltd.