Journal of Physical Chemistry B, Vol.108, No.48, 18530-18534, 2004
AB(5)-type hydrogen storage alloys as catalysts in hydrogen-diffusion electrodes for novel H-2/hydride//perovskite/O-2 alkaline fuel cells
Development of a non-noble-metal catalyst electrode is an important issue in the research and development of fuel cells. The catalytic activity and durability of AB(5)-type hydrogen storage alloys used in hydrogen-diffusion electrodes for alkaline fuel cells are evaluated. The experiments demonstrate that the activity and stability for hydrogen oxidation is greatly improved if the particle size is decreased from 5-30 to 1-10 mum. This also improves the electrode stability. SEM and XRD analyses show that no disintegration of the smaller catalyst particles is observed in long-term tests. A novel H-2/hydride//perovskite/O-2 alkaline fuel cell was constructed as a non-noble-metal fuel cell concept. The results showed that both gas-diffusion electrodes had high catalytic activities and good stability. A maximum power density of 54 mW/cm(2) was achieved at 120 mA/cm(2) when using H-2/O-2 and 49 mW/cm(2) at 100 mA/cm(2) when using H-2/air.