Browsing by Author "Zhao, WG"

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    Optimizing the structure of layered cathode material for higher electrochemical performance by elucidating structural evolution during heat processing
    (Elsevier, 2020-12-01) Huang, ZY; Chu, MH; Wang, R; Zhu, WM; Zhao, WG; Wang, CQ; Zhang, YJ; He, LH; Chen, J; Deng, SH; Mei, LW; Kan, WH; Avdeev, M; Pan, F; Xiao, YG
    Improving electrochemical performance of cathode materials for lithium-ion batteries requires comprehensive understanding of their structural properties which could facilitate or impede the diffusion of lithium during charge-discharge. In order to optimize the structure and improve the electrochemical performance of layered cathode material, the detailed structural evolution as a function of heat treatment temperature in LiNi0.8Co0.1Mn0.1O2 was investigated by in-situ and ex-situ neutron powder diffraction methods. We show that both cycling stability and rate performance of LiNi0.8Co0.1Mn0.1O2 can be improved by performing heat treatment at 400 °C, which is attributed to the optimization of surface structure and the enlargement of c/a ratio. Heat treatment of LiNi0.8Co0.1Mn0.1O2 at higher temperature induces a layered-to-rock-salt structure phase transition accompanied with the precipitation of lithium oxide. A 3D phase diagram, which correlates the high temperature phases and room temperature phases, is constructed. The presentation of comprehensive phase diagrams up to 1000 °C could provide the basis for further research on not only synthesis strategy but also thermal stability in Ni-rich layered cathode materials. © 2020 Elsevier Ltd.