Eliminating water hazards and regulating electrode-electrolyte interfaces by multifunctional sacrificial electrolyte additives for long-life lithium metal batteries

Lithium-metal anodes coupled with high-nickel ternary cathodes offer the potential for high-energy-density batteries. However, the practical cycling stability of lithium-metal batteries poses a significant challenge due to the hydrolysis reaction of LiPF6 in common commercial electrolytes and the unstable electrode-electrolyte interface at high temperatures. Here we demonstrate that stable cycling can be realized by using an appropriate amount of multifunctional sacrificial additives, triethoxy(3,3,3-trifluoropropyl)silane (TTFS). The cycling stability is ascribed to the TTFS's ability to inhibit the hydrolysis of LiPF6 by the presence of strong Si−O bond, which efficiently captures trace H2O and HF in common electrolytes. In addition, TTFS contributes to preferentially form robust interfaces on both anodes and cathodes, leading to the inhibition of capacity degradation in the cell. The Li||LiNi0.8Co0.1Mn0.1O2 cell retains a capacity retention rate of 62.1% after 500 cycles at 25℃ and 81.2% after 160 cycles at a high temperature 60℃, advancing practical lithium-metal batteries.