THE SIZE EFFECT OF AIR-EXPOSED Zr–Mn–Cr–Ni–V ALLOY PARTICLES ON THE CYCLIC RESISTANCE OF THEIR ELECTRODES FOR METAL HYDRIDE ACCUMULATORS

Abstract

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 pressed from an air-exposed Zr–Mn–Cr–Ni–V alloy powder, while this influence is negligible for electrodes made of unexposed powder. The maximum resistance is shown by electrodes with the smallest particle size. Processing in a 30% KOH solution improves the activation and practically does not affect the cyclic resistance. Reduction of binding additives from 5 to 3% increases the maximum discharge capacity of the electrodes and slightly improves the cyclic resistance. Increase in the binding content from 5 to 10% reduces the porosity of the electrodes, which leads to their faster destruction. According to X-ray diffraction, the phase composition and the crystallite size of the alloy powders with particles <100 μm, 70–50 μm, and 50–40 μm after exposure in air for 10 days at room temperature remained unchanged.