论文期刊

论文标题    Suppressing capacity fading and voltage decay of Li-rich layered cathode material by a surface nano-protective layer of CoF2 for lithium-ion batteries.
作者    Chong, S. K; Chen, Y. Z; Yan, W.W; Guo, S.W; Tan, Q; Wu, Y. F; Jiang, T; Liu, Y.
发表/完成日期    2016-07-12
期刊名称    Journal of Power Sources
期卷    332
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论文简介    Li-rich layered oxides have been regarded as valuable cathode materials for high energy density lithium-ion batteries. However, high initial irreversible capacity, bad rate capability, as well as serious capacity fading and voltage decay hinder their commercial application. In this paper, a nano CoF2 protective layer is coated on the surface of Li1.2Ni0.2Mn0.6O2 via a facial wet chemistry method. A high initial discharge capacity of 264.4 mAh g1 is obtained for 0.5% CoF2-coated sample and 259.1 mAh g1 for 1% CoF2-coated sample owing to the suppression of irreversible release of O2 and the contribution of electrochemical conversion of CoF2/LiF. Furthermore, 1% CoF2-coated sample exhibits the excellent rate capability of 167.5 mAh g1 at 5 C rate, the superior cycling stability with the capacity retention of 241.0 mAh g1 and the ameliorative voltage drop of 0.312 V at 0.1C after 100 cycles. The enhanced rate performance as well as stability of capacity and voltage can be attributed to the nano coatings which inhibit the electrolyte-electrode side reaction, enhance the electrochemical kinetics and mitigate structure transition from layered to spinel phase.