物理化学学报

所属专题: 金属锂负极

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基于局部高盐界面润湿策略构筑的固态金属锂软包电池

朱高龙1,2,3,5, 赵辰孜3, 袁洪1, 南皓雄3,4, 赵铂琛3, 侯立鹏3, 何传新2, 刘全兵4, 黄佳琦1   

  1. 1 北京理工大学前沿交叉科学研究院, 北京 100081;
    2 深圳大学化学与化工学院, 功能高分子深圳市重点实验室, 广东 深圳 518000;
    3 清华大学化学工程系, 绿色化学反应工程与技术北京市重点实验室, 北京 100084;
    4 广东工业大学轻工化工学院, 广州 510006;
    5 深圳大学光电工程学院, 光电子器件与系统(教育部/广东省)重点实验室, 广东 深圳 518060
  • 收稿日期:2020-05-05 修回日期:2020-05-27 录用日期:2020-06-10 发布日期:2020-06-18
  • 通讯作者: 黄佳琦 E-mail:jqhuang@bit.edu.cn
  • 基金资助:
    国家重点研发计划(2016YFA0202500, 2016YFA0200102), 国家自然科学基金(21676160, 21808124, U1801257), 博士后基金(2019T120098)资助项目

Liquid Phase Therapy with Localized High-Concentration Electrolytes for Solid-State Li Metal Pouch Cells

Gaolong Zhu1,2,3,5, Chenzi Zhao3, Hong Yuan1, Haoxiong Nan3,4, Bochen Zhao3, Lipeng Hou3, Chuangxin He2, Quanbing Liu4, Jiaqi Huang1   

  1. 1 Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, P. R. China;
    2 Shenzhen Key Laboratory of Functional Polymer, College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518000, Guangdong Province, P. R. China;
    3 Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China;
    4 School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China;
    5 Key Laboratory of Optoelectronic Devices Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P. R. China
  • Received:2020-05-05 Revised:2020-05-27 Accepted:2020-06-10 Published:2020-06-18
  • Supported by:
    The project was supported by the National Key Research and Development Program of China (2016YFA0202500, 2016YFA0200102), the National Natural Science Foundation of China (21676160, 21808124, U1801257), and the China Postdoctoral Science Foundation (2019T120098).

摘要: 固态金属锂电池因其优异的安全性和高的理论能量密度被认为是最具前景的下一代储能电池体系之一。随着以硫化物为代表的高离子导率电解质被逐渐开发,金属锂与固态电解质界面成为限制固态电池应用的主要瓶颈。金属锂/电解质的固固界面存在着界面接触差、界面电荷传输阻力高等问题。本文以固态金属锂软包电池为研究对象,通过由1,1,2,2-四氟乙基-2,2,3,3-四氟丙基醚、乙二醇二甲醚与双三氟磺酰亚胺锂组成的局部高盐液态电解液(HFE-DME LiTFSI)对金属锂/固态电解质界面进行润湿,增加金属锂与固态电解质之间的离子接触,降低离子传输阻力,从而提高锂离子在界面的传输能力。在30 mm×30 mm Li | Li4Ti5O12 (LTO)固态软包电池中,通过3.0 μL·cm-2 HFE-DME LiTFSI局部高盐液态电解液润湿金属锂与固态电解质界面,软包电池的界面电阻从4366 Ω·cm-2 降低到了64 Ω·cm-2。在0.1C与0.5C倍率下,LTO的放电比容量分别达到107与96 mAh·g-1。同时,Li-S固态软包电池在0.01C及0.02C下,比容量也达到了1100与932 mAh·g-1

关键词: 固态软包电池, 金属锂负极, 硫化物电解质, 界面润湿

Abstract: Solid-state Li metal batteries are considered promising next-generation energy storage systems due to its exceptional advantages in terms of safety and high energy density. The continuous process on the development of solid-state fast ionic electrolytes enables the solid-state battery to operate at room temperature. Among these, sulfide-based solid electrolytes have attracted significant attentions due to their extremely high ionic conductivity, excellent deformability, and mild low-temperature processability. However, the full demonstration of practical batteries remains challenging due to the slow lithium-ion transport kinetics at working solid-solid interfaces. The sluggish interfacial transport kinetics mainly result from the poor solid-solid contacts, resulting in poor battery performance. Especially for solid-state pouch cells, the high local current due to the poor contact is amplified by the high working current, leading to rapid failure. Constructing fast ion transport paths between the Li metal anode and solid electrolyte interface is key for the practical application of solid-state batteries. Here a simple protocol was developed to realize fast ionic transportation by wetting the solid electrolyte/Li metal anode interface with localized high salt concentration liquid electrolyte. First, 3.5 mmol lithium trifluoroalfonylimide (LiTFSI) was added into 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE) and dimethoxyethane (DME) mixed solvent, and stirred to obtain uniformly dispersed localized high-concentration liquid electrolyte, denoted as HFE-DME LiTFSI. The fluidity of liquid electrolyte ensures sufficiently conformal contacts between lithium anode and liquid electrolyte, as well as solid-state electrolyte and liquid electrolyte. Thus, fast ion transportation channels were constructed between the solid electrolyte and Li metal anode by wetting HFE-DME LiTFSI at a concentration of 3.0 μL·cm-2. After liquid phase therapy, the interfacial resistance of solid-state Li | Li4Ti5O12 (LTO) pouch cell rapidly reduced from 4366 to 64 Ω·cm-2 and even lower than the cell that was pressed at 3 MPa in the assemble process (340 Ω·cm-2). This suggests that the ion transport kinetics are significantly improved by liquid phase therapy. Therefore, the solid-state Li metal pouch cell with dimensions of 30 mm×30 mm showed excellent cycling performances with specific capacities of 107 and 96 mAh·g-1 at 0.1C and 0.5C, respectively. Furthermore, the solid-state Li-S pouch cell delivered capacities of 1100 and 932 mAh·g-1 at 0.01C and 0.02C, respectively. This study demonstrates the effectiveness of the novel liquid phase therapy to construct fast ionic transportation channels, which providing an effective strategy for the practical application of solid-state Li metal pouch cells.

Key words: Solid-state pouch cell, Lithium metal anode, Sulfide electrolyte, Liquid phase therapy

MSC2000: 

  • O646