Electronic Supplementary Material

Atomic-scale structural and chemical evolution of Li3V2(PO4)3 cathode cycled at high voltage window Shulin Chen1,2,3, Jian Zou1, Yuehui Li3, Ning Li3, Mei Wu3, Jinghuang Lin2, Jingmin Zhang3, Jian Cao2, Jicai Feng2, Xiaobin Niu1, Jianming Bai4, Junlei Qi2 (), Peng Gao2,3,5,6 (), Liping Wang1 (), and Hong Li7

1 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 2 State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China 3 Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China 4 National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA 5 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China 6 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China 7 Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China Supporting information to https://doi.org/10.1007/s12274-019-2421-9

 Figure S1 The carbon coated Li3V2(PO4)3 (LVP/C). (a) A high resolution transmission electron microscopy (HRTEM) image of LVP/C and the width of the amorphous carbon layer is about 5–10 nm. (b) The Thermo Gravimetric Analyzer (TGA) test of LVP/C during heating in air at a heating rate of 10 °C min-1.

 Figure S2 The Energy dispersive X-ray spectroscopy (EDS) mapping of LVP/C. (a) The scanning TEM (STEM) image, (b) the corresponding spectrum and (c) EDS mappings of V, P, O, and C.

Address correspondence to Junlei Qi, jlqi@hit.edu.cn; Peng Gao, p-gao@pku.edu.cn; Liping Wang, lipingwang@uestc.edu.cn

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 Figure S3 The electrochemical performance of LVP/C in the voltage range of 3.0–4.3 V cycling at different rates. (a) The charge/discharge voltage profiles for the first cycle, (b) the corresponding cycling performance. (c) The Nyquist plots of impedance data from the cells evolutions during the cycling at 0.2C. (d) The Rct acquired from the Nyquist plots before and after 500 cycles.

 Figure S4 The charge-transfer resistance of LVP cycled in 3.0-4.3 V and 3.0-4.8 V.

 Figure S5 The micromorphology and chemical composition of the SEI film. (a, b) TEM images of the cycled LVP (a) in the voltage range 3.0-4.8 V and (b) 3.0-4.3 V after 500 cycles at 0.2C. (c-h) The corresponding STEM image and the EDS mappings of (a) to show the elemental distribution in the cycled LVP.

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 Figure S6 The x value in Li3-XV2(PO4)3 based on the EELS line scan in Fig. 3(a).

 Figure S7 The chemical evolution for the LVP particle after 500 cycles in 3.0-4.8 V. (a) The STEM-HAADF image. The blue arrow shows the scanning direction for acquiring spectra. The line scan includes 126 points and the distance between two near points is 1 nm. (b) The EELS line scan spectra and (c) the corresponding 2D maps to visualize the peak shift of V-L edges. The dashed arrows indicate the scanning direction. (d) The energy values of V-L3 edge extracted from (c) as a function of distance, which shows the total red-shift is about ~1.1 eV.

 Figure S8 The simulated electron diffraction (ED) pattern of LVP along the [1-20] direction.

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 Figure S9 The interface of LVP and the Li-deficient phase Li3-xV2(PO4)3 after 500 cycles in 3.0-4.8 V. (a) A high resolution TEM image of the interface with a 10-20 nm width LVP out layer and inner Li-deficient Li3-xV2(PO4)3 core along the [20-1] zone axis judging from (b) the corresponding fast Fourier transform pattern. (c) The SAED pattern shows additional (0 2h+1 0) diffraction spots, compared with (d) the simulated ED pattern of LVP.

Table S1 The lithium ion diffusion coefficients of LVP at various states

Samples σ DLi+ (cm2 s-1)

3.0-4.8V pristine 85.8 1.6×10-13 3.0-4.8V 500 cycles 154.1 4.8×10-14

3.0-4.3V pristine 40.9 6.9×10-13 3.0-4.3V 500 cycles 17.3 3.8×10-12