Correlation between crystal structure and electrochemical properties of C14 Laves-phase alloys

Abstract

By examining the relationships between the structure and the thermodynamic and electrochemical properties for Zr 1− x Ti x (V 0.1Mn a Ni b E c ) α ( x=0.1–0.3, a=0.28–0.30, b=0.50–0.57, c=0.05–0.12, α=1.6–1.8, E=Co, Fe, Mo) alloy system with C14 type structure, the following results were obtained. The partial molar enthalpy for hydride formation decreases linearly with decreasing cell volume V C14 of the C14 phase. This means that the hydride becomes unstable with decreasing V C14, as is the case for the C15 type structure. Both −Δ H and V C14 decrease with decreasing average atomic radius of the alloy, and the correlation coefficient was sufficiently high for each value. The discharge capacity and dischargeability also depend on −Δ H and V C14.