储能科学与技术 ›› 2024, Vol. 13 ›› Issue (7): 2124-2130.doi: 10.19799/j.cnki.2095-4239.2024.0307

• 低温电池专刊 • 上一篇    下一篇

间二氟苯稀释剂稳定电极界面助力低温锂金属电池

廖世接1(), 魏颖1, 黄云辉1, 胡仁宗2, 许恒辉1()   

  1. 1.华中科技大学，湖北 武汉 430074
    2.华南理工大学，广东 广州 510641
  • 收稿日期:2024-04-07 修回日期:2024-04-16 出版日期:2024-07-28 发布日期:2024-07-23
  • 通讯作者: 许恒辉 E-mail:m202271054@hust.edu.cn;xuhh@hust.edu.cn
  • 作者简介:廖世接（1999—），男，硕士研究生，从事低温电解液的研究，E-mail：m202271054@hust.edu.cn；
  • 基金资助:
    国家自然科学基金重点项目(52231009);国家自然科学基金青年项目(52302253);湖北省重点研发计划项目(2023BAB028)

1，3-Difluorobenzene diluent-stabilizing electrode interface for high-performance low-temperature lithium metal batteries

Shijie LIAO1(), Ying WEI1, Yunhui HUANG1, Renzong HU2, Henghui XU1()   

  1. 1.Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
    2.South China University of Technology, Guangzhou 510641, Guangdong, China
  • Received:2024-04-07 Revised:2024-04-16 Online:2024-07-28 Published:2024-07-23
  • Contact: Henghui XU E-mail:m202271054@hust.edu.cn;xuhh@hust.edu.cn

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摘要：

锂离子电池凭借其能量密度高、输出电压高、循环寿命长等优点而广泛应用于各大领域，然而其在低温应用场景下电化学性能较差，严重限制了其应用。本文采用不同氟取代位置的氟取代苯作为稀释剂，制备了在室温和低温均具有优异循环性能的低温电解液。结果表明，间二氟苯作为低温电解液的稀释剂制备的低温电解液(13DFB)在-20 ℃的电导率为1.252 mS/cm，同时具有5.2 V的宽电化学窗口。间二氟苯稀释剂有效抑制SEI中的Li2CO3的形成，且对LiNi0.6Co0.2Mn0.2O2 (NCM 622)正极颗粒有显著的保护作用。在-20 ℃和4.4 V截止电压下，采用改性低温电解液组装的Li/NCM622的软包电池可稳定循环200圈，容量保持率为92.8%。本工作提出的方法简单有效，可提升电解液的低温性能，并展示了其在实际中应用的潜力。

关键词: 锂离子电池, 低温电解液, 间二氟苯, 稀释剂

Abstract:

Lithium-ion batteries are widely used across various industries owing to their superior characteristics such as high energy density, high output voltage, and prolonged cycle life. However, their electrochemical efficiency drastically declines in low-temperature conditions, constraining their practical applications. To overcome this limitation, a novel low-temperature electrolyte, distinguished by exceptional cycling performance at ambient and low temperatures, was developed using fluoro-substituted benzene with varied fluorine substitution positions as diluents. Notably, the use of 1, 3-difluorobenzene as a diluent led to the development of an electrolyte, designated as 13DFB, exhibiting a conductivity of 1.252 mS/cm at -20 ℃ and a broad electrochemical window of 5.2 V. The inclusion of 1, 3-difluorobenzene in the electrolyte considerably reduces the formation of Li2CO3 in solid-electrolyte interphase and provides a protective layer to LiNi0.6Co0.2Mn0.2O2 (NCM 622) cathode particles. Moreover, when this modified electrolyte is used in a pouch cell configuration with a Li/NCM 622 combination at -20 ℃ and a cutoff voltage of 4.4 V, it achieves stable cycling for 200 cycles with a capacity retention of 92.8%. This study introduces an effective and straightforward strategy to enhance the low-temperature performance of electrolytes, demonstrating substantial potential for practical deployment.

Key words: lithium-ion battery, low temperature electrolyte, 1,3-difluorobenzene, diluent

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