The effect of particle size on the electrochemical properties of hydrogen absorbing alloy electrodes

The investigation of the effect of the particle size of hydrogen-absorbing-alloys on the electrochemical properties of electrodes revealed that the electrochemical reactivity of small-particle electrodes containing conductive powder was excellent, but that the discharge capacity of the alloy electrodes composed of small particles containing no conductive powder was small. A possible reason for this reduced capacity is the existence of particles that cannot be discharged due to weak contact between the particles as the volume of the alloy changed. Thus, batteries made from electrodes composed of particles larger than 25 μm were found to have superior charge–discharge cycle characteristics.