题目：

Enhancing the Reversibility of Lattice Oxygen Redox Through Modulated Transition Metal–Oxygen Covalency for Layered Battery Electrodes

作者：

Chen Cheng,¹ Chi Chen,² Shiyong Chu,³ Haolv Hu,¹ Tianran Yan,¹ Xiao Xia,¹ Xuefei Feng,⁴ Jinghua Guo,⁴ Dan Sun,² Jinpeng Wu,^5,* Shaohua Guo,^3,* and Liang Zhang^1,*

单位：

¹Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, China

²CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Key Laboratory of Nanomaterials Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences, Fuzhou 350002, China

³College of Engineering and Applied Sciences National Laboratory of Solid State Microstructures   Collaborative Innovation Center of Advanced Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University,  Nanjing 210093, China

⁴Advanced Light Source Lawrence Berkeley National Laboratory,  Berkeley, CA 94720, USA

⁵Department of Electrical Engineering Tsinghua University, Beijing 100084, China

摘要：

Utilizing reversible lattice oxygen redox (OR) in battery electrodes is an essential strategy to overcome the capacity limitation set by conventional transition metal redox. However, lattice OR reactions are often accompanied with irreversible oxygen oxidation, leading to local structural   transformations and voltage/capacity fading. Herein, it is proposed that the   reversibility of lattice OR can be remarkably improved through modulating transition metal–oxygen covalency for layered electrode of Na-ion batteries. By developing a novel layered P2-Na_0.6Mg_0.15Mn_0.7Cu_0.15O₂ electrode, it is demonstrated that the highly electronegative Cu dopants can  improve the lattice OR reversibility to 95% compared to 73% for Cu-free counterpart, as directly quantified through high-efficiency mapping of resonant inelastic X-ray scattering. Crucially, the large energetic overlap  between Cu 3d and O 2p states dictates the rigidity of oxygen framework, which effectively mitigates the structural distortion of local oxygen environment upon (de) sodiation and leads to the enhanced lattice OR reversibility. The electrode also exhibits a completely solid-solution reaction with an ultralow volume change of only 0.45% and a reversible metal migration upon cycling,   which together ensure the improved electrochemical performance. These results   emphasize the critical role of transition metal–oxygen covalency for enhancing the reversibility of lattice OR toward high-capacity electrodes employing OR chemistry.

影响因子：

30.849

分区情况：

一区

链接：

https://doi.org/10.1002/adma.202201152