利用MnO2增强Ni-MH电池正极中CoOOH导电网络稳定性

摘要

Spherical nickel hydroxide is the electrochemically active material for the positive electrodes of MH-Ni batteries. Both the β-Co (OH)2 introduced in the preparation of nickel hydroxide and CoO added during the battery assembly would transform into β-CoOOH and become a three-dimensional conductive network among spherical nickel hydroxides after the battery formation was finished, which could improve the utility ratio of the active material.However, after the battery was shelved at high temperature for a long time, when its voltage declined to a certain point, some β-CoOOH was reduced into low-solubility β-Co (OH)2. As a result, the secondary and tertiary conductive networks were destroyed and the battery suffered a permanent capacity loss. In this paper, it is showed that adding only 1％ MnO2 into the positive electrode can ensure 100％ capacity retention even after the battery is stored at high temperature for quite some time.%球形Ni(OH)2是制作Ni-MH电池的正极材料,在制备球形Ni(OH)2时掺杂一定比例的β-Co(OH)2,做电池时往正极中添加一定量的CoO,做成电池经化成后,β-Co(OH)2和CoO都会转变成导电性好的β-CoOOH,在球形Ni(OH)2内部和球镍之间形成一个能提高氢氧化镍利用率的立体导电网络.但是当电池在长时间高温搁置后,随着电池电压下降到某一值时β-CoOOH就会减少,变成溶解度低的β-Co(OH)2,这样第二级和第三级导电网络就会被破坏,从而使电池的容量出现永久性损失.阐述了往Ni-MH电池正极中添加1%MnO2就能确保电池在高温长时间搁置后电池仍能保持100%容量.