Single-Solvent-Based Electrolyte Enabling a High-Voltage Lithium-Metal Battery with Long Cycle Life

摘要

The application of Li-metal-anodes (LMA) can significantly improve the energydensity of state-of-the-art lithium ion batteries. Lots of new electrolytesystems have been developed to form a stable solid electrolyte interphase(SEI) films, thereby achieving long-term cycle stability of LMA. Unfortunately,the common problem faced by these electrolytes is poor oxidation stability,which rarely supports the cycling of high-voltage Li-metal batteries (LMBs).In this work, a new single-component solvent dimethoxy(methyl)(3,3,3-trifluoropropyl) silane is proposed. The electrolyte composed of this solventand 3 m LiFSI salt successfully supports the long-term cycle stability oflimited-Li (50 μm)high loading LiCoO_2 (≈20 mg cm~(?2)) cell at 4.6 V.Experiments and theoretical research results show that the outstandingperformance of the electrolyte in high-voltage LMBs is mainly attributed to itsunique solvation structures and its great ability to build a highly stable androbust interphase on the surface of LMA and high-voltage cathodes.Interestingly, this proposed electrolyte system builds a stable SEI film rich inLiF and Li_3N on the surface of LMA by improving the two-electron reductionactivity of FSI~? without adding LiNO_3, the well-known additive used forLMBs. The design idea of the proposed electrolyte can guide the developmentof high-voltage LMBs.