Superior Li<sup>+</sup> Kinetics by "Low-Activity-Solvent" Engineering for Stable Lithium Metal Batteries.

Tu, Haifeng; He, Zhigang; Sun, Ao; Mushtaq, Farwa; Li, Linge; Wang, Zhicheng; Kong, Yaping; Huang, Rong et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

The structure of solvated Li<sup>+</sup> has a significant influence on the electrolyte/electrode interphase (EEI) components and desolvation energy barrier, which are two key factors in determining the Li<sup>+</sup> diffusion kinetics in lithium metal batteries. Herein, the "solvent activity" concept is proposed to quantitatively describe the correlation between the electrolyte elements and the structure of solvated Li<sup>+</sup>. Through fitting the correlation of the electrode potential and solvent concentration, we suggest a "low-activity-solvent" electrolyte (LASE) system for deriving a stable inorganic-rich EEI. Nano LiF particles, as a model, were used to capture free solvent molecules for the formation of a LASE system. This advanced LASE not only exhibits outstanding antidendrite growth behavior but also delivers an impressive performance in Li/LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> cells (a capacity of 169 mAh g<sup>-1</sup> after 250 cycles at 0.5 C).