Volume 61, Issue 36 e202208345
Communication

Synergy of Weakly-Solvated Electrolyte and Optimized Interphase Enables Graphite Anode Charge at Low Temperature

Yang Yang

Yang Yang

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

These authors contributed equally to this work.

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Zhong Fang

Zhong Fang

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

These authors contributed equally to this work.

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Yue Yin

Yue Yin

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

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Yongjie Cao

Yongjie Cao

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

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Prof. Yonggang Wang

Prof. Yonggang Wang

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

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Prof. Xiaoli Dong

Corresponding Author

Prof. Xiaoli Dong

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

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Prof. Yongyao Xia

Corresponding Author

Prof. Yongyao Xia

Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433 China

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First published: 14 July 2022
Citations: 99

Graphical Abstract

This work offers a weakly-solvated electrolyte and a high-quality SEI by room-temperature formation process, which enables graphite electrode with a fast-charging 6C-rate and low-temperature operation. Moreover, the Gr||LiFePO4 full cell exhibits a capacity retention of 78 % at −30 °C and a high discharge capacity of 37 % even at −60 °C.

Abstract

Graphite anode suffers from great capacity loss and even fails to charge (i.e. Li+-intercalation) under low temperature, mainly arising from the large overpotential including sluggish de-solvation process and insufficient ions movement in the solid electrolyte interphase (SEI). Herein, an electrolyte is developed by utilizing weakly solvated molecule ethyl trifluoroacetate and film-forming fluoroethylene carbonate to achieve smooth de-solvation and high ionic conductivity at low temperature. Evolution of SEI formed at different temperatures is further investigated to propose an effective room-temperature SEI formation strategy for low-temperature operations. The synergetic effect of tamed electrolyte and optimized SEI enables graphite with a reversible charge/discharge capacity of 183 mAh g−1 at −30 °C and fast-charging up to 6C-rate at room temperature. Moreover, graphite||LiFePO4 full cell maintains a capacity retention of 78 % at −30 °C, and 37 % even at a super-low temperature of −60 °C. This work offers a progressive insight towards fast-charging and low-temperature batteries.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

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