Zhong Yijun, Xu Xiaomin, Veder Jean-Pierre, Shao Zongping
WA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA 6845, Australia.
John de Laeter Centre, Curtin University, Perth, WA 6102, Australia.
iScience. 2020 Mar 27;23(3):100943. doi: 10.1016/j.isci.2020.100943. Epub 2020 Feb 27.
Rechargeable Zn-ion batteries working with manganese oxide cathodes and mild aqueous electrolytes suffer from notorious cathode dissolution during galvanostatic cycling. Herein, for the first time we demonstrate the dynamic self-recovery chemistry of manganese compound during charge/discharge processes, which strongly determines the battery performance. A cobalt-modified δ-MnO with a redox-active surface shows superior self-recovery capability as a cathode. The cobalt-containing species in the cathode enable efficient self-recovery by continuously catalyzing the electrochemical deposition of active Mn compound, which is confirmed by characterizations of both practical coin-type batteries and a new-design electrolyzer system. Under optimized condition, a high specific capacity over 500 mAh g is achieved, together with a decent cycling performance with a retention rate of 63% over 5,000 cycles. With this cobalt-facilitated deposition effect, the battery with low concentration (0.02 M) of additive Mn in the electrolyte (only 12 atom % to the overall Mn) maintains decent capacity retention.
使用氧化锰阴极和温和水性电解质的可充电锌离子电池在恒电流循环过程中存在严重的阴极溶解问题。在此，我们首次展示了锰化合物在充放电过程中的动态自修复化学过程，这对电池性能起着决定性作用。具有氧化还原活性表面的钴改性δ-MnO作为阴极表现出卓越的自修复能力。阴极中的含钴物种通过持续催化活性锰化合物的电化学沉积实现高效自修复，这在实际的硬币型电池和新设计的电解槽系统的表征中得到了证实。在优化条件下，实现了超过500 mAh g的高比容量，以及在5000次循环中保持率为63%的良好循环性能。基于这种钴促进的沉积效应，电解液中添加剂锰浓度较低（0.02 M，仅占总锰的12原子%）的电池仍保持良好的容量保持率。
