Enabling stable 4.6 V LiCoO_(2) cathode through oxygen charge regulation strategy  

作　　者：Wen Zhang Xiaoyu Zhang Fangyuan Cheng Meng Wang Jing Wan Yuyu Li Jia Xu Yi Liu Shixiong Sun Yue Xu Chun Fang Qing Li Jiantao Han Yunhui Huang 

机构地区：[1]State Key Laboratory of Material Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China [2]Department of Applied Physics,Chongqing University,Chongqing 401331,China [3]Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University,Wuhan 430056,Hubei,China

出　　处：《Journal of Energy Chemistry》2023年第1期557-565,I0014,共10页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China (52102249, 52172201, 51732005, 51902118);the China Postdoctoral Science Foundation (2019M662609 and 2020T130217);the international postdoctoral exchange fellowship program (PC2021026);the Major Technological Innovation Project of Hubei Province (2019AAA019) for financial support。

摘　　要：LiCoO_(2) is the preferred cathode material for consumer electronic products due to its high volumetric energy density. However, the unfavorable phase transition and surface oxygen release limits the practical application of LiCoO_(2)at a high-voltage of 4.6 V to achieve a higher energy density demanded by the market. Herein, both bulk and surface structures of LiCoO_(2)are stabilized at 4.6 V through oxygen charge regulation by Gd-gradient doping. The enrichment of highly electropositive Gd on LiCoO_(2) surface will increase the effective charge on oxygen and improve the oxygen framework stability against oxygen loss.On the other hand, Gd ions occupy the Co-sites and suppress the unfavorable phase transition and microcrack. The modified LiCoO_(2) exhibits superior cycling stability with capacity retention of 90.1% over 200 cycles at 4.6 V, and also obtains a high capacity of 145.7 m Ah/g at 5 C. This work shows great promise for developing high-voltage LiCoO_(2) at 4.6 V and the strategy could also contribute to optimizing other cathode materials with high voltage and large capacity, such as cobalt-free high-nickel and lithiumrich manganese-based cathode materials.

关 键 词：Li-ion batteries 4.6 V LiCoO_(2) Gd-gradient doping Oxygen charge Cycle stability 

分 类 号：TM91[电气工程—电力电子与电力传动]