Abstract:The Co(Ⅲ)-coated spherical nickel hydroxide powder is optimum as positive electrode of high power Ni-MH battery because of its excellent property. But the performances at high temperature (above 50 ℃) is still not satisfied. In the present paper, the effect of element erbium, used as additive by different methods to prepare positive electrode, on the high temperature performances of the Ni-MH batteries is studied. It is found that the charge acceptance ability of the spherical Ni(OH)₂ electrode with element erbium as additive is improved. The discharge capacities of Ni(OH)₂ coated with 1% (atomic fraction) Er(OH)₃ and mechanically added with 1% (atomic fraction) Er₂O₃ at 1C are 12.6% and 11.7%, respectively, higher than those of the samples without erbium at 70 ℃.

Key words: Ni-MH battery; nickel hydroxide electrode; Er-coating; high temperature performance