储能科学与技术 ›› 2023, Vol. 12 ›› Issue (7): 2119-2133.doi: 10.19799/j.cnki.2095-4239.2023.0212

• 储能锂离子电池系统关键技术专刊 • 上一篇    下一篇

锂离子电池产气机制及基于电解液的抑制策略

徐冲(), 徐宁, 蒋志敏, 李中凯, 胡洋, 严红, 马国强()   

  1. 浙江省化工研究院有限公司,浙江 杭州 310023
  • 收稿日期:2023-04-10 修回日期:2023-05-20 出版日期:2023-07-05 发布日期:2023-07-25
  • 通讯作者: 马国强 E-mail:xuchong01@sinochem.com;maguoqiang@sinochem.com
  • 作者简介:徐冲(1995—),男,硕士,工程师,研究方向为锂离子电池电解液,E-mail:xuchong01@sinochem.com
  • 基金资助:
    国家发展改革委科技项目(2112-360598-04-01-781944);科技厅省属科研院所扶持专项(LTCRRD(t)LM2021005)

Mechanisms of gas evolution and suppressing strategies based on the electrolyte in lithium-ion batteries

Chong XU(), Ning XU, Zhimin JIANG, Zhongkai LI, Yang HU, Hong YAN, Guoqiang MA()   

  1. Zhejiang Chemical Industry Research Institute Co. Ltd. , Hangzhou 310023, Zhejiang, China
  • Received:2023-04-10 Revised:2023-05-20 Online:2023-07-05 Published:2023-07-25
  • Contact: Guoqiang MA E-mail:xuchong01@sinochem.com;maguoqiang@sinochem.com

摘要:

便携式设备、电动汽车和储能设施的快速发展对锂离子电池的成本、充电倍率、使用寿命和安全性等提出了更高要求。然而,锂离子电池在循环和存储过程中会产气,造成电池体积膨胀、极片/隔膜错位以及电池极化增加,是导致电池寿命衰减甚至引发安全问题的重要原因。本文从锂离子电池产气种类出发,总结了锂离子电池中H2、O2、烯烃、烷烃、CO2和CO 6类主要气体的产生机制以及电池温度、电压窗口、电极材料等因素对气体产生的影响,并讨论了这些气体产生与电池性能变化和电池安全之间的关系。此外,本文基于电解液视角提出了抑制策略,主要围绕提升电解液稳定性和构建稳固的电极/电解液界面两个维度展开。清除电池中的活性氧、痕量水和氢氟酸,降低溶剂中环状碳酸酯含量以及使用氟代溶剂均可以有效提升电解液稳定性,使用各类功能添加剂调控电极/电解液界面组分可以有效提升电池界面稳定性,最终达到抑制产气的效果。最后,本文提出了目前针对电池产气仍需解决的问题,为后续深入探究电池产气机理以及开发更有效的产气抑制策略进行了展望。

关键词: 产气机制, 抑制策略, 添加剂, 电解液, 锂离子电池

Abstract:

Rapid development of portable devices, electric vehicles, and energy storage power stations has led to the increasing need of optimizing the cost, cycling life, charging time, and safety of lithium-ion batteries (LIBs). Gas generation during cycling and storage causes volume expansion and electrode/separator dislocation, which can increase electrochemical polarization and lead to decreased battery lifespan or safety hazards. Herein, we summarize the mechanisms with respect to the primary gases that evolve in LIBs, including oxygen, hydrogen, alkenes, alkanes, and carbon oxide, and describe the effect of operating temperature, voltage window, and electrode materials on gas generation. We also describe the relationship between this gas generation and LIB performance. We further propose several electrolyte-based strategies that focus on increasing the stability of the electrolyte and electrode/electrolyte interface. Specifically, the electrolyte stability is increased by employing functional additives to scavenge trace water, hydrofluoric acid, and active oxygen species, reducing the proportion of cyclic carbonates, and by using fluorinated solvents in the electrolyte. The adoption of film-forming additives can effectively improve the stability of the electrode/electrolyte interface, suppressing gas generation. In addition, we discuss the challenges and urgent issues related to gas generation in LIBs and provide unique perspectives on the intrinsic mechanism for developing increasingly efficient gas-suppression methods.

Key words: gas evolution, suppressing strategies, additives, electrolyte, lithium-ion batteries

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