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Nano Research

Article Title

Atomic-scale structural and chemical evolution of Li3V2(PO4)3 cathode cycled at high voltage window

Authors

Shulin Chen, School of Materials and Energy, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
Jian Zou, School of Materials and Energy, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Yuehui Li, Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
Ning Li, Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
Mei Wu, Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
Jinghuang Lin, State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
Jingmin Zhang, Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
Jian Cao, State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
Jicai Feng, State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
Xiaobin Niu, School of Materials and Energy, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Jianming Bai, National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
Junlei Qi, State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
Peng Gao, State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China Collaborative Innovation Center of Quantum Matter, Beijing 100871, China International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
Liping Wang, School of Materials and Energy, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Hong Li, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

Keywords

lithium-ion batteries, Li-deficient lithium vanadium phosphate, capacity fading, solid electrolyte interphase, scanning transmission electron microscopy, electron energy loss spectroscopy

Abstract

Here, by using atomically resolved scanning transmission electron microscopy and electron energy loss spectroscopy, we investigate the structural and chemical evolution of Li3V2(PO4)3 (LVP) upon the high-voltage window (3.0–4.8 V). We find that the valence of vanadium gradually increases towards the core corresponding to the formation of electrochemically inactive Li3−xV2(PO4)3 (L3−xVP) phases. These Li-deficient phases exhibit structure distortion with superstructure stripes, likely caused by the migration of the vanadium, which can slow down the lithium ion diffusion or even block the diffusion channels. Such kinetic limitations lead to the formation of Li-deficient phase along with capacity loss. Thus, the LVP continuously losses of electrochemical activity and Li-deficient phases gradually grow from the particle core towards the surface during cycling. After 500 cycles, the thickness of active LVP layer decreases to be ~ 5–20 nm. Moreover, the micromorphology and chemical composition of solid electrolyte interphase (SEI) have been investigated, indicating the thick SEI film also contributes to the capacity loss. The present work reveals the structural and chemical evolution in the cycled electrode materials at an atomic scale, which is essential to understand the voltage fading and capacity decaying of LVP cathode.

Graphical Abstract

Publisher

Tsinghua University Press

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