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Stable Solvent-Derived Inorganic-Rich Solid Electrolyte Interphase (SEI) for High-Voltage Lithium-Metal Batteries

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posted on 2022-06-07, 15:34 authored by Ziyu Chen, Bin Wang, Yan Li, Fengwei Bai, Yongchao Zhou, Chengzong Li, Tao Li
The inorganic-rich solid electrolyte interphase (SEI) has attracted wide attention due to its good compatibility with the lithium (Li) metal anode. Herein, a stable solvent-derived inorganic-rich SEI is constructed from a hydrofluoroether-diluted low-concentration electrolyte, which simultaneously possesses the merits of nonflammability and low cost (0.5 M LiPF6). The addition of hydrofluoroether enhances the coordination strength between Li+ and solvents, altering the decomposition path of solvents to yield more Li2O. The abundant Li2O crystals endow the SEI with improved passivating ability and ion conductivity. The 30 μm Li|NCM523 (3.8 mAh cm–2) batteries with solvent-derived Li2O-rich SEI deliver 96.1% capacity retention after 200 cycles. Notably, a 1.1 Ah Li|NCA pouch cell delivers an energy density of 374 Wh kg–1 and achieves 45 stable cycles. This study points out that tuning the decomposition of solvents provides a new approach to construct stable inorganic-rich SEI for practical Li-metal batteries.

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