Enhanced discharge capacity and cycling properties in high-samarium, praseodymium/neodymium-free, and low-cobalt A2B7 electrode materials for nickel-metal hydride battery

A high-Sm, Pr/Nd-free, and low-Co La0.95Sm0.66Mg0.40Ni6.25Al0.42Co0.32 alloy is reported as an A2B7-type electrode for Ni/MH batteries. The structural characteristics and electrochemical properties of this alloy have been investigated. La0.95Sm0.66Mg0.40Ni6.25Al0.42Co0.32 is composed of La2Ni7 and LaNi5 phases, and shows high discharge capacity and excellent cyclic property. The discharge capacity can reach 311.8 mAh/g and 227.0 mAh/g at large discharge currents of 2C and 5C, respectively, and 80% of the capacity is retained after 239 cycles at 1C.