The Particle Size Effect of Air-Exposed Zr–Mn–Cr–Ni–V Alloy on the Cyclic Resistance of Electrodes for Metal Hydride Batteries

The influence of the particle size and porosity of electrodes on their cyclic resistance was studied. It is found that the particle size influences the cyclic resistance of electrodes compacted from the air-exposed Zr–Mn–Cr–Ni–V alloy powder, while this effect is negligible for electrodes made of the unexposed powder. The maximum resistance is shown by electrodes with the smallest particle size. Treatment of the electrodes in a 30% KOH solution improves their activation and hardly affects their cyclic resistance. Decrease of the binder content from 5 to 3% increases the maximum discharge capacity of the electrodes and slightly improves the cyclic resistance. Increase in the binder content from 5 to 10% reduces the porosity of the electrodes, which leads to their faster failure. According to X-ray diffraction, the phase composition and crystallite size of the alloy powders with particles smaller than 100 μm and with 70–50 μm and 50–40 μm particles after exposure in air for 10 days at room temperature remained unchanged.