关键词: 常压回流, 钙锰矿, 钴离子掺杂, 锂离子二次电池, 正极材料

Abstract: Cobalt-doped todorokites were prepared by refluxing at atmospheric pressure,and then charactered by X-ray diffraction(XRD),thermogravimetry(TG) and the analysis of chemical compositions.These measurements showed that all of the refluxing products were single phase of todorokites and the structure formulas were MgxCoyMnOz·nH2O,where 0.18 ≤ x ≤ 0.22,0 ≤ y ≤ 0.24,2.10 ≤ z ≤ 2.53,and 0.35 ≤ n ≤0.73.The electrochemical characteristics of cobalt-doped todorokites were examined as lithium insertion hosts for cathodes in rechargeable lithium batteries.The first discharge capacity of undoped todorokite electrode was 211 mAh/g and the discharge capacity became 37 mAh/g after 30 cycles.The Mg0.18Co0.12MnO2.19·0.45 H2O with doping Co 10% displayed the best discharge behavior,which showed a high discharge capacity of 219 mAh/g at first cycle and the cycling capacity of 102 mAh/g after 100 cycles.

Key words: refluxing at atmospheric pressure, todorokite, cobalt-doped, lithium-ion secondary battery, cathode materials