Local Electronic Structure Modulation Enables Fast-Charging Capability for Li-Rich Mn-Based Oxides Cathodes With Reversible Anionic Redox Activity |
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Authors: | Xianggang Gao Haiyan Zhang Shihao Li Shuai Zhang Chaohong Guan Xiaoping Hu Juanlang Guo Yanqing Lai Zhian Zhang |
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Affiliation: | 1. School of Metallurgy and Environment, Hunan Province Key Laboratory of Nonferrous Value-Added Metallurgy, Engineering Research Center of the Ministry of Education for Advanced Battery Materials, Central South University, Changsha, Hunan, 410083 P. R. China;2. School of Metallurgy and Environment, Hunan Province Key Laboratory of Nonferrous Value-Added Metallurgy, Engineering Research Center of the Ministry of Education for Advanced Battery Materials, Central South University, Changsha, Hunan, 410083 P. R. China Hunan Changyuan LiCo Co., Ltd, Changsha, Hunan, 410205 P. R. China;3. University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 P. R. China;4. School of Materials Science and Engineering, Central South University, Changsha, Hunan, 410083 P. R. China |
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Abstract: | Anionic and cationic redox chemistries boost ultrahigh specific capacities of Li-rich Mn-based oxides cathodes (LRMO). However, irreversible oxygen evolution and sluggish kinetics result in continuous capacity decay and poor rate performance, restricting the commercial fast-charging cathodes application for lithium ion batteries. Herein, the local electronic structure of LRMO is appropriately modulated to alleviate oxygen release, enhance anionic redox reversibility, and facilitate Li+ diffusion via facile surface defect engineering. Concretely, oxygen vacancies integrated on the surface of LRMO reduce the density of states of O 2p band and trigger much delocalized electrons to distribute around the transition metal, resulting in less oxygen release, enhancing reversible anionic redox and the MnO6 octahedral distortion. Besides, partially reduced Mn and lattice vacancies synchronously stimulate the electrochemical activity and boost the electronic conductivity, Li+ diffusion rate, and fast charge transfer. Therefore, the modified LRMO exhibits enhanced cyclic stability and fast-charging capability: a high discharging capacity of 212.6 mAh·g−1 with 86.98% capacity retention after 100 cycles at 1 C is obtained and to charge to its 80%, SOC is shortened to 9.4 min at 5 C charging rate. This work will draw attention to boosting the fast-charging capability of LRMO via the local electronic structure modulation. |
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Keywords: | anionic redox electronic structure modulation fast-charging Li-rich Mn-based oxides cathodes oxygen vacancy |
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