Li<sub>2</sub>ZrF<sub>6</sub> protective layer enabled high-voltage LiCoO<sub>2</sub> positive electrode in sulfide all-solid-state batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39747862.
- Also identified by DOI 10.1038/s41467-024-55695-9 and PMC identifier 11696131.
- Licence recorded as CC BY-NC-ND.
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Abstract
The application of high-voltage positive electrode materials in sulfide all-solid-state lithium batteries is hindered by the limited oxidation potential of sulfide-based solid-state electrolytes (SSEs). Consequently, surface coating on positive electrode materials is widely applied to alleviate detrimental interfacial reactions. However, most coating layers also react with sulfide-based SSEs, generating electronic conductors and causing gradual interface degradation and capacity fading. To address this, we propose a Li<sub>2</sub>ZrF<sub>6</sub> coating layer on LiCoO<sub>2</sub>, which exhibits minimal reaction with SSEs, and its decomposition products are electron-conductive-free. Furthermore, this coating layer also efficiently mitigates the layered-to-spinel/rock-salt surface structural transformation in LiCoO<sub>2</sub>. As a result, the In-Li|Li<sub>6</sub>PS<sub>5</sub>Cl | Li<sub>2</sub>ZrF<sub>6</sub>-LiCoO<sub>2</sub> all-solid-state cell demonstrates an initial areal capacity of 5.2 mAh cm<sup>-2</sup> and a capacity retention of 80.5% after 1500 cycles at 70 mA/g with high LiCoO<sub>2</sub> areal mass loading (30.19 mg cm<sup>-2</sup>) and a cut-off voltage of 3.9 V (corresponding to potential of 4.5 V versus Li<sup>+</sup>/Li), at 25 °C.