Lithium hexamethyldisilazide as electrolyte additive for efficient cycling of high-voltage non-aqueous lithium metal batteries
Danfeng Zhang, Ming Liu, Jiabin Ma, Ke Yang, Zhen Chen, Kaikai Li, Chen Zhang, Yinping Wei, Min Zhou, Peng Wang, Yuanbiao He, Wei Lv, Quan‐Hong Yang, Feiyu Kang, Yan‐Bing He, Yan‐Bing He, Yan‐Bing He
Abstract
Abstract 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 0.8 Co 0.1 Mn 0.1 O 2 (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.