Lithium hexamethyldisilazide as electrolyte additive for efficient cycling of high-voltage non-aqueous lithium metal batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36379928.
- Also identified by DOI 10.1038/s41467-022-34717-4 and PMC identifier 9666536.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> (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.