Symmetry Breaking Enabled Stable Oxygen Redox in Li‐Rich Cathodes via π‐Type Interaction
Abstract
Abstract Effectively stabilizing oxygen redox is the most challenging task for the practical applications of high‐energy‐density Li‐rich cathode materials. However, how to accurately tune the oxygen energy level to achieve reversible redox remains puzzling so far. In this work, we achieve stable oxygen redox in layered Li‐rich materials over the whole voltage range without irreversible O 2 release by adjusting the interlayer metal cation environment adjacent to the ligand. Combining synchrotron X‐ray absorption spectroscopy and theoretical analysis of metal‐ligand orbital combinations, we confirm the obvious charge transfer from O to Ni due to the π‐type interaction between Ni 3 d spin‐down t 2g orbitals and O 2 p orbitals. Furthermore, Ab initio molecular dynamics simulations reveal the spontaneous symmetry breaking of the Ni coordination environment after Li extraction under the π‐type interaction, which enhances the intrinsic competition between anion and cation oxidation, keeping π* state (from O 2 p splitting) below the metal band to avoid over‐oxidation. As a result, the modified material shows improved electrochemical performance and stable structural/interface evolution. This work provides new insights into the relationship between the adjacent metal environment and the ligand O redox reactions.
Article Details
Authors (13)
Fu‐Da Yu
Engineering Research Center of Environment‐Friendly Functional Materials Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen China
Zhe‐Jian Yi
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Hai‐Nan Wang
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Jia‐Zhen Zhao
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Yang‐Qian Zhang
Department of Physics, JC STEM Lab of Energy and Materials Physics City University of HongKong HongKong 999077 P.R. China
Yang Ren
Ji‐Gang Zhou
Canadian Light Source Inc Saskatoon S7N 2 V3 Canada
Ji‐Huai Wu
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Zhang Lan
Engineering Research Center of Environment‐Friendly Functional Materials Ministry of Education Fujian Provincial Key Laboratory of Photoelectric Functional Materials Institute of Materials Physical Chemistry Huaqiao University Xiamen 361021 China
Yi‐Ming Xie
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Lan‐Fang Que
Engineering Research Center of Environment‐Friendly Functional Materials, Ministry of Education College of Materials Science and Engineering Huaqiao University Xiamen 361021 P.R. China
Yun‐Shan Jiang
School of Energy and Environment City University of Hong Kong Hong Kong SAR China
Zhen‐Bo Wang
State Key Laboratory of Space Power‐Sources MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage MOE Engineering Research Center for Electrochemical Energy Storage and Carbon Neutrality in Cold Regions School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin China