Electrochemical Properties of Zr–Mn–Cr–Ni–V Alloy in Long-Term Cycling After Air Oxidation

A zirconium-containing alloy was subjected to air oxidation to examine its influence on the lattice parameters and cyclic resistance. The samples made of freshly prepared alloy powder and of powder oxidized in air for 7, 15, and 30 days were studied. Cyclic voltammetry was used to analyze in detail the current–voltage characteristics and X-ray diffraction was employed to determine the lattice parameters. The freshly prepared alloy was found to be very unstable and significantly lose its activity in the hydrogenation–dehydrogenation process. This results from oxidation of the alloy, which induces interfacial stresses and causes mechanical damage of the electrodes. Air oxidation of the alloy powder followed by compaction of the electrodes stabilizes its electrochemical properties and, as a result, increases the cyclic resistance. According to X-ray diffraction, the phase ratio after air oxidation remains practically unchanged, and the lattice expansion (within 1%) can be attributed to measurement errors.