In-operando optical observations of alkaline fuel cell electrode surfaces during harsh cycling tests

The durability of low-cost fuel cells is one of the last technical challenges to be overcome before the widespread adoption of fuel cells can become a reality. Most research concentrates on polymer electrolyte membrane or solid oxide fuel cells in this topic with little published regarding the durability of recirculating liquid electrolyte alkaline fuel cells. In this paper we present an investigation into the durability of this fuel cell variant under harsh load cycling, air starvation and fuel starvation conditions. In the study, making use of the high ionic conductivity of the electrolyte, a novel rig design was utilised, which allowed the surfaces of the electrodes to be constantly monitored optically during the experiments. This demonstrated the good physical durability of the anode during the test protocols whilst highlighted the instability of the manganese-cobalt spinel cathode, used in this study, during the air starvation protocols. The load cycling stability of the alkaline fuel cells used was found to be good with the standard configuration giving only around a 2.7% voltage degradation at 100 mA cm−2 operating point over 8000 load cycles.