无机材料学报 ›› 2023, Vol. 38 ›› Issue (7): 785-792.DOI: 10.15541/jim20220761 CSTR: 32189.14.10.15541/jim20220761

所属专题: 【能源环境】超级电容器,锂金属电池,钠离子电池和水系电池(202409)

• 研究论文 • 上一篇    下一篇

双锂盐凝胶复合电解质的制备及其在锂金属电池中的应用

郭宇翔1(), 黄立强2, 王刚1(), 王宏志1()   

  1. 1.东华大学 材料科学与工程学院 纤维材料改性国家重点实验室, 上海 201620
    2.同济大学 材料科学与工程学院 车用新能源研究院, 上海 201804
  • 收稿日期:2022-12-19 修回日期:2023-02-10 出版日期:2023-03-10 网络出版日期:2023-03-09
  • 通讯作者: 王 刚, 研究员. E-mail: gwf8707@dhu.edu.cn;
    王宏志, 教授. E-mail: wanghz@dhu.edu.cn
  • 作者简介:郭宇翔(1997-), 男, 硕士研究生. E-mail: 18939371679@163.com
  • 基金资助:
    中央高校基本科研业务费专项资金资助(2232021G-12);中央高校基本科研业务费专项资金资助(2232020A-03);中央高校基本科研业务费专项资金资助(2232021G-02);上海市自然科学基金(21520710700);国家自然科学基金(51903189)

Dual-lithium-salt Gel Complex Electrolyte: Preparation and Application in Lithium-metal Battery

GUO Yuxiang1(), HUANG Liqiang2, WANG Gang1(), WANG Hongzhi1()   

  1. 1. State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China
    2. Institute of New Energy for Vehicles, School of Materials Science and Engineering, Tongji University, Shanghai 201804, China
  • Received:2022-12-19 Revised:2023-02-10 Published:2023-03-10 Online:2023-03-09
  • Contact: WANG Gang, professor. E-mail: gwf8707@dhu.edu.cn;
    WANG Hongzhi, professor. E-mail: wanghz@dhu.edu.cn
  • About author:GUO Yuxiang (1997-), male, Master candidate. E-mail: 18939371679@163.com
  • Supported by:
    Fundamental Research Funds for the Central Universities(2232021G-12);Fundamental Research Funds for the Central Universities(2232020A-03);Fundamental Research Funds for the Central Universities(2232021G-02);Science and Technology Commission of Shanghai Municipality(21520710700);National Natural Science Foundation of China(51903189)

摘要:

锂金属具有理论比容量高、还原电位低及储量高等优势, 是高能量密度锂离子电池的理想负极材料之一。然而, 传统的液态电解质与锂金属的不相容性极大地限制了其应用。本研究采用原位聚合的方法, 开发了一种与锂金属负极相容性良好的凝胶复合电解质(Gel Complex Electrolyte, GCE)。向该电解质中引入的双锂盐体系可与聚合物组分共同作用, 拓宽了电解质的电化学窗口(5.26 V, 商用电解液的电化学窗口为3.92 V), 并能够获得较高的离子电导率(30 ℃, 1×10-3 S·cm-1)。锂金属负极表面的形貌表征及元素分析结果显示, 在双锂盐体系的作用下, GCE表现出对锂金属明显的保护效果, 锂金属负极的体积效应及枝晶生长得到了明显抑制。同时, 匹配商业磷酸铁锂(LiFePO4)正极材料组装的锂金属全电池也展现出优异的循环稳定性和良好的倍率性能, 在25 ℃下以0.2C(1C=0.67 mA·cm-2)的恒定电流循环200圈后, 容量保持率可以达到92.95%。研究表明, 该GCE能有效提高锂金属电池的安全稳定性以及综合的电化学性能, 有望提供一种普适化的准固态电解质设计策略。

关键词: 锂金属, 原位聚合, 凝胶复合电解质

Abstract:

Metallic Li is one of the ideal anodes for high energy density lithium-ion battery due to its high theoretical specific capacity, low reduction potential as well as abundant reserves. However, the application of Li anodes suffer from serious incompatibility with traditional organic liquid electrolyte. Herein, a gel complex electrolyte (GCE) with satisfactory compatibility with metallic Li anode was constructed via in situ polymerization. The double lithium salt system introduced into the electrolyte can cooperate with the polymer component, which broadens electrochemical window of the electrolyte to 5.26 V compared to 3.92 V of commercial electrolyte, and obtains a high ionic conductivity of 1×10-3 S·cm-1 at 30 ℃ as well. Results of morphology characterization and elemental analysis of Li anode surface show that GCE exhibits obvious protective effect on lithium metal under the condition of double lithium salt system, and volume effect and dendrite growth of Li anode are obviously inhibited. At the same time, the lithium metal full battery, assembled with commercial lithium iron phosphate (LiFePO4) cathode material, exhibits excellent cycling stability and rate performance. The capacity retention rate of the battery reaches 92.95 % after 200 cycles at a constant current of 0.2C (1C = 0.67 mA·cm-2) at 25 ℃. This study indicates that the GCE can effectively improve the safety, stability and comprehensive electrochemical performance of lithium-metal battery, which is expected to provide a strategy for universal quasi-solid electrolyte design.

Key words: metallic Li, in-situ polymerization, gel complex electrolyte

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