氢化物电极中Mn的偏析

THE SEGREGATION OF Mn IN HYDRIDE ELECTRODES

镍/氢化物(Ni/MH)电池具有高能量、无电解液浓缩、耐过充放、无毒、不使用贵金属等特点。70年代起已开始这方面的研究,近年来尤其活跃。美国、日本等已试制了性能较好的此类电池。我国南开大学、机电部十八所、浙江大学等也已开展了研究。

The segregation and dissolution of M_n at the electrodes of hydrogen storage alloys, LaMmMnCoNi and AlMmMnCoNi (Mm-alloy of rare earth rich in lanthanum), have been studied in cycling course using XPS and electron probe techniques. It was observed that Mn inside the electrodes dispersed rapidly to the electrode surfaces in the active stage, forming MnO_2. Both the capacities of the electrodes and the Mn content on the electrode surfaces gave maximum values in the cycling course, The segregation and dissolution of Mn in the hydrogen storage alloy electrode containing Al were slower than that in the alloy electrode without Al, The alloy electrode with and without Al in 80% discharge showed a cycling life of 520 and 350 times, respectively. It is concluded that Al may inhibit the segregation and dissolution of Mn and extend the cycling life of the eletrode.