储能科学与技术 ›› 2020, Vol. 9 ›› Issue (2): 392-399.doi: 10.19799/j.cnki.2095-4239.2020.0060

• 庆祝陈立泉院士八十寿辰专刊 • 上一篇    下一篇

基于多氟代醚和碳酸酯共溶剂的钠离子电池电解液特性

车海英1,2, 喻妍1, 杨馨蓉1,2, 廖小珍1, 李林森1, 邓永红3, 马紫峰1()   

  1. 1. 上海交通大学化工系，上海电化学能源器件工程技术研究中心，上海 200240
    2. 浙江钠创;新能源有限公司，浙江 绍兴 312000
    3. 深圳新宙邦科技股份有限公司，广东 深圳 518118
  • 收稿日期:2020-01-30 修回日期:2020-02-08 出版日期:2020-03-05 发布日期:2020-03-15
  • 通讯作者: 马紫峰 E-mail:zfma@sjtu.edu.cn
  • 作者简介:车海英（1986—），女，博士，工程师，研究方向为钠离子电池材料和器件开发，E-mail：chysyx@sjtu.edu.cn；
  • 基金资助:
    国家自然科学基金(21938005);上海市科委项目(19DZ1205500);浙江省重点研发计划(2020C01128┫项目。)

Behavior of sodium-ion battery electrolytes based on the co-solvents of polyfluorinated ether and organic carbonates

CHE Haiying1,2, YU Yan1, YANG Xinrong1,2, LIAO Xiaozhen1, LI Linsen1, DENG Yonghong3, MA Zifeng1()   

  1. 1. Shanghai Electrochemical Energy Devices Research Center, Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
    2. Zhejiang Natrium Energy Co. , Ltd. ，Shaoxing 312000, Zhejiang, China
    3. Shenzhen Capchem Technology Co. , Ltd. ，Shenzhen 518118, Guangdong, China
  • Received:2020-01-30 Revised:2020-02-08 Online:2020-03-05 Published:2020-03-15
  • Contact: Zifeng MA E-mail:zfma@sjtu.edu.cn

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摘要：

溶剂对锂/钠离子电池电解液离子电导率和安全性起着重要作用。碳酸酯类溶剂已应用于商业化的锂离子电池及钠离子电池研发中，但是其热化学稳定性有待提高。本工作率先在NaPF6/EC-DEC-FEC基础电解液中加入1,1,2,2-四氟乙基-2,2,3,3-四氟丙基醚（F-EPE），部分取代DEC形成共溶剂，制备不同溶剂比的新型电解液，研究E-EPE对电解液可燃性、电导率、分解电位和电化学窗口等特性影响。将所制备的电解液应用于NaNi1/3Fe1/3Mn1/3O2（NFM）正极材料的电化学特征研究，揭示电极/电解液界面作用机理。结果表明，F-EPE能增强电解液的抗氧化能力，分解电压提高。随着F-EPE含量增加，电解液的阻燃性提高，当其含量达到30%时（EDH523F），形成不可燃电解液。当F-EPE含量为20%时（EDH532F），NFM容量保持率最佳，150圈后的容量保持率从75.7%（EC-DEC-FEC）提升至82.9%。SEM、ICP、EIS和XPS测试表明，相比基础电解液，EDH532F电池具有更稳定的电极界面和更低的界面阻抗，从而具有更好的循环性能。

关键词: 钠离子电池, 多氟代醚, 电解液, 阻燃溶剂

Abstract:

Solvents are essential for the ionic conductivity and safety of the electrolytes for lithium/sodium ion batteries. Organic carbonates have been used as solvents in commercial lithium-ion and sodium-ion batteries; however, their thermochemical stability needs to be improved. In this study, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (F-EPE) was first added to the basic electrolyte of NaPF6/EC-DEC-FEC, which partially replaced DEC to form a co-solvent, and a new electrolyte with a different solvent ratio was prepared. The effects of co-solvent F-EPE on the flammability, conductivity, and electrochemical window of the prepared electrolyte were investigated. The prepared electrolyte was applied to study the electrochemical characteristics of NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode materials and to reveal the mechanism of the electrode–electrolyte interface. The influence of the electrolyte on the electrochemical performance of the battery was discussed, and the related interface mechanism was explained. A flammability test revealed that an increase in the content of F-EPE can improve the flame retardancy of the electrolyte and the safety of the corresponding battery. When the content of F-EPE reaches 30%, the electrolyte becomes nonflammable. An electrochemical window test revealed that F-EPE can improve the antioxidation ability and increase the decomposition voltage of the electrolyte. SEM, ICP, EIS, and XPS tests show that a battery with EDH532F has a more stable electrode interface and lower interface impedance compared to one with EC-DEC-FEC as the electrolyte. Thus, the cell with EDH532F has better cycling performance. Moreover, when the F-EPE content is 20%, the cycling performance of the cell is the best, and the capacity retention increases from 75.7% (EC-DEC-FEC) to 82.9% (EDH532F) after 150 cycles.

Key words: sodium-ion battery, polyfluorinated ether, electrolyte, non-flammable solvents

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