Electrode–Electrolyte Interfaces and Hydrogen Fluoride Elimination Achieved by Electrolyte Additive Boost High-Performance LRO/Li Cells

In this article, a multifunctional electrolyte additive, tris(dimethylsiloxy)phenylsilane (TDSPS), is proposed to improve the electrochemical cyclability of 4.8 V lithium-rich oxide (LRO)/Li cells. Electrochemical texts demonstrate that the incorporation of 1 vol % TDSPS improves the capacity retention of LRO/Li cells at 25 °C. Specifically, the cell with the electrolyte containing 1 vol % TDSPS exhibits excellent capacity retention of 81.6% after 200 cycles at 25 °C (0.5 C, 1 C = 250 mAh g–1), while the cell with the baseline electrolyte retains only 34.3%. Systematic theoretical calculations and comprehensive material characterizations elucidate that TDSPS opearates through three primary mechanisms: (1)TDSPS undergoes preferential oxidation on the cathode surface, facilitating the formation of a high-stability protective layer; (2)TDSPS is preferentially reduced on the lithium metal anode surface, effectively inhibiting the growth of lithium dendrites; (3)TDSPS possesses the ability to neutralize and eliminate hazardous hydrofluoric acid (HF), thereby mitigating electrolyte degradation and enhancing cell stability.