Probing component contributions and internal polarization in silicon-graphite composite anode for lithium-ion batteries with an electrochemical-mechanical model

• Published in: Chinese physics B Vol. 31; no. 7; pp. 78201 - 684
• Main Authors: Chen, Yue, Guo, Fuliang, Yang, Lufeng, Lu, Jiaze, Liu, Danna, Wang, Huayu, Zheng, Jieyun, Yu, Xiqian, Li, Hong
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.06.2022; School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%Beijing Advanced Innovation Center for Materials Genome Engineering,Key Laboratory for Renewable Energy,Beijing Key Laboratory for New Energy Materials and Devices,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China%Beijing WeLion New Energy Technology Co.,Ltd.,Beijing 100176,China%Li Auto Inc.,Beijing 101399,China; Tianmu Lake Institute of Advanced Energy Storage Technologies,Liyang 213300,China%Beijing Advanced Innovation Center for Materials Genome Engineering,Key Laboratory for Renewable Energy,Beijing Key Laboratory for New Energy Materials and Devices,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China; School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China; Beijing WeLion New Energy Technology Co.,Ltd.,Beijing 100176,China; Beijing Advanced Innovation Center for Materials Genome Engineering,Key Laboratory for Renewable Energy,Beijing Key Laboratory for New Energy Materials and Devices,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China; Tianmu Lake Institute of Advanced Energy Storage Technologies,Liyang 213300,China
• Subjects: electrochemical interactions; polarization; rate performance; Si-Gr; Si-Gr; rate performance; electrochemical interactions; polarization
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/ac6012

Silicon–graphite (Si–Gr) composite anodes are attractive alternatives to replace Gr anodes for lithium-ion batteries (LIBs) owing to their relatively high capacity and mild volume change. However, it is difficult to understand electrochemical interactions of Si and Gr in Si–Gr composite anodes and internal polarization of LIBs with regular experiment methods. Herein, we establish an electrochemical-mechanical coupled model to study the effect of rate and Si content on the electrochemical and stress behavior in a Si–Gr composite anode. The results show that the composites of Si and Gr not only improve the lithiation kinetics of Gr but also alleviate the voltage hysteresis of Si and decrease the risk of lithium plating in the negative electrode. What’s more, the Si content is a tradeoff between electrode capacity and electrode volume variation. Further, various internal polarization contributions of cells using Si–Gr composite anodes are quantified by the voltage decomposition method. The results indicate that the electrochemical polarization of electrode materials and the electrolyte ohmic over-potential are dominant factors in the rate performance of cells, which provides theoretical guidance for improving the rate performance of LIBs using Si–Gr composite anodes.