Low-Temperature and Fast-Charging Lithium Metal Batteries Enabled by Solvent-Solvent Interaction Mediated Electrolyte.

Huang, Akang; Ma, Zheng; Kumar, Pushpendra; Liang, Honghong; Cai, Tao; Zhao, Fei; Cao, Zhen; Cavallo, Luigi et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Lithium metal batteries utilizing lithium metal as the anode can achieve a greater energy density. However, it remains challenging to improve low-temperature performance and fast-charging features. Herein, we introduce an electrolyte solvation chemistry strategy to regulate the properties of ethylene carbonate (EC)-based electrolytes through intermolecular interactions, utilizing weakly solvated fluoroethylene carbonate (FEC) to replace EC, and incorporating the low-melting-point solvent 1,2-difluorobenzene (2FB) as a diluent. We identified that the intermolecular interaction between 2FB and solvent can facilitate Li<sup>+</sup> desolvation and lower the freezing point of the electrolyte effectively. The resulting electrolyte enables the LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub>||Li cell to operate at -30 °C for more than 100 cycles while delivering a high capacity of 154 mAh g<sup>-1</sup> at 5.0C. We present a solvation structure and interfacial model to analyze the behavior of the formulated electrolyte composition, establishing a relationship with cell performance and also providing insights for the electrolyte design under extreme conditions.