Effect of Lu_2 O_3 on Charge/ discharge Performances of Spherical Nickel Hydroxide at High Temperature

摘要

Nickel-metal hydride (Ni/MH) batteries are one of promising batteries for electric vehicle applications, but at high temperature the charge efficiency of nickel electrode is very low. In order to improve the high-temperature-efficiency of nickel electrode, spherical nickel hydroxide mixed with various ratios of Lu2O3 was used as active material of pasted nickel electrodes. The results of charge/discharge experiments, cyclic voltammetric measurements and XRD characterizations have shown that after addition of LU_2O_3, the oxygen evolution overpotential is elevated much, the charge efficiency of nickel electrode at high temperature is greatly improved and the content of beta-NiOOH phase increases in charged electrodes . In addition, the mixed ratio of LU_2O_3 has different effects on high temperature performances of nickel electrode at different charge/discharge currents, 3.5 percent is the optimum mixed ratio, and the action of LU_2O_3 on high temperature electrochemical behaviors is more apparent when nickel electrodes are charged at small current than large current.