Enhanced electrochemical performances via introducing LiF electrolyte additive for lithium ion batteries

• Published in: Ceramics international Vol. 45; no. 14; pp. 18106 - 18110
• Main Authors: Lei, Tongxing, Xue, Longlong, Li, Yunjiao, Chen, Yongxiang, Zhu, Jie, Deng, Shiyi, Lian, Xuan, Cao, Guolin, Li, Wei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2019
• Subjects: Enhanced electrochemical performance; LiF additive; LiNi0.6Co0.2Mn0.2O2; Lithium ion battery; Residual current; Self-discharge behavior; Lithium ion battery; Residual current; Self-discharge behavior; LiNi0.6Co0.2Mn0.2O2; LiF additive; Enhanced electrochemical performance
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2019.05.216

High working potential and temperature put nonnegligible threats on electrochemical stability and safety performance of lithium ion batteries (LIBs). In this paper the carbonate-based electrolyte is modified with LiF additive to improve the comprehensive properties of cells in which a metallic lithium anode is paired with a LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode under the extreme conditions of high cut-off potential, high current rate or even high temperature (55 °C). The tests of self-discharge behavior and chronoamperometry present that the introduction of LiF additive contributes to relieving self-discharge of cells and side reactions on the surface of electrodes. The cells with 100 ppm exhibit the improved cyclic performance (81.6% of initial capacity 195.4 mAh g−1), high-rate capability (150.6 mAh g−1 at 8 C) and high-temperature performance. Additionally after 100 cycles over 3.0–4.6 V, the results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) on electrodes reveal that the cathodes in LiF-reinforced electrolyte retain more stable layered structure and more intact spherical secondary particles than those in original electrolyte.