Effects of Mm(NiCoAlMn)5 hydrogen storage alloy coated with Ni-Co-P alloy by electroless plating on electrochemical properties of hydride electrodes
来源期刊：中国有色金属学报(英文版)2003年第4期
论文作者：孙春文 郭占成 唐致远 郭鹤桐
文章页码：938 - 942
Key words：rare earths based hydrogen-storage alloys; electroless Ni-Co-P alloy plating; MH-Ni battery
Abstract: The effect of chemical plating with Ni-Co-P alloy on the properties of MH electrodes is investigated. The results show that the efficiency of storage alloy and the activation of MH electrode have been improved by introducing 1.74% cobalt in the Ni-Co-P alloy coating. The initial discharge capacity is 208mAh/g. The maximum discharge capacity gets to 298.5mAh/g. At the same time the cycle life of MH electrodes is improved. The discharge capacity of MH electrodes coated with Ni-Co-P is 88% of the maximum discharge capacity after 300 cycles. Whereas the discharge capacity of bare alloy electrodes retains 62% of the maximum capacity after 300 cycles. An increment of discharge capacity is mainly due to the superposition of the oxidation current of Co as well as improved efficiency of microcurrent collection. The effect of Ni-Co-P alloy coating by electroless plating on the kinetic properties of hydride electrode has been systematically investigated by electrochemical techniques. The results indicate that the kinetic properties of MH electrodes, including exchange current density, limiting current density, have been improved markedly. This improvement of kinetic properties leads to the decrease of the overpotential of anodic and cathodic polarization.
