Enabling an intrinsically safe and high‐energy‐density 4.5 V‐class Li‐ion battery with nonflammable electrolyte
Ziqi Zeng, Xuemei Liu, Xiaoyu Jiang, Zhenjie Liu, Zhangquan Peng, Xiangming Feng, Weihua Chen, Dingguo Xia, Xinping Ai, Hanxi Yang, Yuliang Cao
Abstract
Abstract Developing nonflammable electrolyte with a wide electrochemical window has become an urgent demand for high‐energy‐density and high‐safe lithium‐ion batteries (LIBs). Herein, a fluorinated nonflammable phosphate electrolyte is developed to construct a safe 4.5 V‐class LIB (Si‐SiC‐C/0.35Li 2 MnO 3 ·0.65LiNi 0.5 Mn 0.5 O 2 ). The proposed fluorinated phosphate electrolyte, 0.8 M LiPF 6 /tris(2,2,2‐trifluoroethyl) phosphate (TFEP) + 5 vol% fluoroethylene carbonate (FEC) + 5 vol% vinylene carbonate (VC), is not only completely nonflammable but also exhibits excellent oxidative/reductive stability on 0.35Li 2 MnO 3 ·0.65LiNi 0.5 Mn 0.5 O 2 cathode and Si‐SiC‐C anode. The in situ differential electrochemical mass spectrometry and X‐ray photoelectron spectroscopy proved that TFEP‐based electrolyte does not decompose into gases but forms a high‐quality electrode‐electrolyte interface on cathode surface at high working potential. The 4.5 V‐class LIBs using 0.8 M LiPF 6 TFEP‐based nonflammable electrolyte shed some light on potential application for high‐safe and low‐cost larger‐scale energy storage. image