The enhanced electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials by low temperature fluorine substitution
The enhanced electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials by low temperature fluorine substitution
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DOI：
10.1016/j.electacta.2013.02.037
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发表时间：
2013-04
影响因子：
6.6
通讯作者：
Peng Yue;Zhixing Wang;Xinhai Li;Xunhui Xiong;Jiexi Wang;Xianwen Wu;Huajun Guo
中科院分区：
文献类型：
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作者：
Peng Yue;Zhixing Wang;Xinhai Li;Xunhui Xiong;Jiexi Wang;Xianwen Wu;Huajun Guo
以氢氧化物共沉淀法合成的LiNi0.6Co0.2Mn0.2O2氧化物为原料，采用NH4F低温（450 ° C）共沉淀法合成了层状氟氧化物LiNi0.6Co0.2Mn0.2O2 − zFz（0 ≤ z ≤ 0.06）正极材料。氟含量对LiNi0.6Co0.2Mn0.2O2 − zFz结构和电化学性能的影响已被广泛研究。XRD结果表明，LiNi0.6Co0.2Mn0.2O2 − zFz（0 ≤ z ≤ 0.06）具有典型的六方结构，不含杂质。组成分析和XPS证实了氟掺入颗粒中。电化学测试结果表明，随着氟含量的增加，首次放电容量略有下降。然而，氟取代改善了循环性能和倍率性能。此外，在完全充电状态下在90 ° C下储存5h后，氟取代的材料表现出比原始材料更好的循环性能。电化学阻抗谱表明，氟取代可以降低电荷转移电阻。总的来说，氟取代对层状LiNi0.6Co0.2Mn0.2O2的电化学性能具有积极的影响。
Layered oxy-fluoride LiNi0.6Co0.2Mn0.2O2−zFz(0≤z≤0.06) cathode materials have been synthesized by a low temperature (450°C) fluorination with NH4F of the corresponding LiNi0.6Co0.2Mn0.2O2oxides that were synthesized by hydroxide co-precipitation method. The effect of fluorine content on the structure and electrochemical performance of the LiNi0.6Co0.2Mn0.2O2−zFzhas been extensively studied. The XRD results reveal that LiNi0.6Co0.2Mn0.2O2−zFz(0≤z≤0.06) has typical hexagonal structure without impurity. The composition analysis and XPS verify fluorine incorporation in the particle. The electrochemical results indicate that the initial discharge capacity slightly decreases with increasing the content of fluorine. However, cycling performance and rate capability are improved by the fluorine substitution. In addition, after stored at 90°C for 5h in fully charged state, fluorine substituted materials exhibit better cycling performance than pristine materials. Electrochemical impedance spectroscopy shows that fluorine substitution can reduce the charge transfer resistance. Overall, fluorine substitution has a positive effect on the electrochemical performance of layered LiNi0.6Co0.2Mn0.2O2.