Non-polar ether-based electrolyte solutions for stable high-voltage non-aqueous lithium metal batteries.

Li, Zheng; Rao, Harsha; Atwi, Rasha; Sivakumar, Bhuvaneswari M; Gwalani, Bharat; Gray, Scott; Han, Kee Sung; Everett, Thomas A et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

The electrochemical instability of ether-based electrolyte solutions hinders their practical applications in high-voltage Li metal batteries. To circumvent this issue, here, we propose a dilution strategy to lose the Li<sup>+</sup>/solvent interaction and use the dilute non-aqueous electrolyte solution in high-voltage lithium metal batteries. We demonstrate that in a non-polar dipropyl ether (DPE)-based electrolyte solution with lithium bis(fluorosulfonyl) imide salt, the decomposition order of solvated species can be adjusted to promote the Li<sup>+</sup>/salt-derived anion clusters decomposition over free ether solvent molecules. This selective mechanism favors the formation of a robust cathode electrolyte interphase (CEI) and a solvent-deficient electric double-layer structure at the positive electrode interface. When the DPE-based electrolyte is tested in combination with a Li metal negative electrode (50 μm thick) and a LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub>-based positive electrode (3.3 mAh/cm<sup>2</sup>) in pouch cell configuration at 25 °C, a specific discharge capacity retention of about 74% after 150 cycles (0.33 and 1 mA/cm<sup>2</sup> charge and discharge, respectively) is obtained.