High-voltage lithium metal batteries suffer from poor cycling stability caused by the detrimental effect on the cathode of the water moisture present in the non-aqueous liquid electrolyte solution, especially at high operating temperatures (e.g., ≥60 °C). To circumvent this issue, here we report lithium hexamethyldisilazide (LiHMDS) as an electrolyte additive. We demonstrate that the addition of a 0.6 wt% of LiHMDS in a typical fluorine-containing carbonate-based non-aqueous electrolyte solution enables a stable Li||LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) coin cell operation up to 1000 or 500 cycles applying a high cut-off cell voltage of 4.5 V in the 25 °C−60 °C temperature range. The LiHMDS acts as a scavenger for hydrofluoric acid and water and facilitates the formation of an (electro)chemical robust cathode|electrolyte interphase (CEI). The LiHMDS-derived CEI prevents the Ni dissolution of NCM811, mitigates the irreversible phase transformation from layered structure to rock-salt phase and suppresses the side reactions with the electrolyte solution.

高压锂金属电池循环稳定性差，这是由于非水电解质溶液中存在的水分对阴极的不利影响，尤其是在高工作温度（例如，≥60°C）下。为了避免这个问题，我们在这里报告了六甲基二硅基氨基锂 (LiHMDS) 作为电解质添加剂。我们证明，在典型的含氟碳酸盐基非水电解质溶液中添加 0.6 wt% 的 LiHMDS 可实现稳定的 Li||LiNi _0.8 Co _0.1 Mn _0.1 O ₂(NCM811) 钮扣电池在 25 °C−60 °C 温度范围内应用 4.5 V 的高截止电池电压可运行高达 1000 或 500 个循环。LiHMDS 充当氢氟酸和水的清除剂，并促进（电）化学稳定的阴极|电解质界面（CEI）的形成。LiHMDS 衍生的 CEI 可防止 NCM811 的 Ni 溶解，减轻从层状结构到岩盐相的不可逆相变，并抑制与电解质溶液的副反应。