Affiliation:
1. Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science & Engineering Beijing Institute of Technology Beijing 100081 China
2. Institute of Advanced Technology Beijing Institute of Technology Jinan 250300 China
3. Weifang University of Science and Technology Shouguang 262700 China
4. Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081 China
Abstract
AbstractLow temperatures (< −20 °C) significantly diminish lithium‐ion battery performance due to freezing issues within commercial electrolytes and the high energy barrier for Li+ desolvation at the interface. Although high‐concentration electrolytes and localized high‐concentration electrolytes enhance Li+ desolvation kinetics featuring anion‐participated solvation structures, their high viscosity and propensity for Li salt precipitation render them unsuitable for low‐temperature environments. This study introduces an anion‐dominated conventional‐concentrations electrolyte (ACCE) created by incorporating Lithium difluorophosphate(LiPO2F2)into a 1 M Lithium bis((trifluoromethyl)sulfonyl)azanide(LiTFSI) Dimethyl carbonate(DMC)/Fluoroethylene carbonate(FEC)/Methyl acetate(MA) electrolyte solution. LiPO2F2, characterized by its poor solubility and strong binding with Li+, demonstrates a pronounced tendency to integrate into the primary solvation sheath of Li+. Moreover, the synergy between LiTFSI and LiPO2F2 establishes a dual anion configuration, unveiling a dual anion‐driven mechanism. This mechanism significantly diminishes the interaction between Li+ and solvent molecules, resulting in reduced desolvation energy under low temperatures. The ACCE exhibits high ionic conductivity of 1.3 mS cm−1 at −50 °C, enabling stable cycling of Li/NCM811 cells at −50 °C, and further allows 0.75 Ah graphite(Gr)/LiNi0.8Co0.1Mn0.1O2(NCM811) batteries dischargeable at −40 °C. This study presents a practical application potential for poorly soluble lithium salts and provides a new avenue for designing electrolytes suitable for low‐temperature applications.
Funder
National Natural Science Foundation of China
Beijing Institute of Technology Research Fund Program for Young Scholars
Cited by
2 articles.
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