储能科学与技术

• 特约文章 • 上一篇    

线性氟代碳酸酯添加剂DTFEC对锂硫电池性能的影响

陈振营,周晶晶,杨军,王久林,努丽燕娜   

  1. 上海电化学能源器件工程技术研究中心,上海交通大学化工系,上海 200240
  • 收稿日期:2017-11-22 修回日期:2017-12-06 出版日期:2017-12-12 发布日期:2017-12-12
  • 通讯作者: 杨军(1959—),教授,主要研究方向为锂(和镁)金属二次电池关键材料,E-mail:yangj723@sjtu.edu.cn
  • 基金资助:
    国家重点基础研究计划(2014CB932303)

Improved performance of lithium sulfur battery with the fluorinated linear carbonate DTFEC as addictive

CHEN Zhenying,ZHOU Jingjing,YANG Jun,WANG Jiulin,NULI Yanna   

  1. Shanghai Electrochemical Energy Devices Research Center,Department of Chemical Engineering, Shanghai Jiao Tong University,Shanghai 200240,China
  • Received:2017-11-22 Revised:2017-12-06 Online:2017-12-12 Published:2017-12-12

摘要:

锂硫(Li-S)电池具有比锂离子电池更高的能量密度,是近10年来的研究热点,但目前锂硫电池的循环性能和倍率性能远远不能满足人们的需求。在本研究中,二(2,2,2-三氟乙基)碳酸酯(DTFEC)作为一种电解液添加剂应用到锂硫电池中,以提高电池的电化学性能,并对DTFEC的添加量进行了筛选和优化。结果表明,DTFEC的添加量对电池性能有很大的影响,当添加体积分数为5% 时,复合硫正极材料(S@pPAN)表现出最佳的循环稳定性和倍率性能。室温条件下进行充放电测试,在1C的充放电电流下,锂硫电池在循环200圈后容量保持率比常规电解液约高20%;在7C的大倍率充放电电流下,依然可以得到1246.3 mAh g-1的可逆比容量。以上结果表明,DTFEC可以有效提高锂硫电池的电化学性能,是一种适合用于锂硫电池电解液体系的添加剂。

关键词: 锂硫电池, DTFEC, 添加剂, 电化学性能

Abstract:

Lithium sulfur (Li-S) battery with the high theoretical energy density has been considered as the most promising next generation of rechargeable batteries, being the research hot topic in the last 10 years. However, the cycle and rate performances couldn't satisfy the actual requirement of people. Here, di-2,2,2-trifluoroethyl carbonate (DTFEC) has been investigated as electrolyte addictive to improve the electrochemical performances of the Li-S batteries for the first time. The electrochemical test results show that the additive has a great influence on the performance of the battery and which is related to the amount of addition. With 5% DTFEC (by volume) added, the sulfur composite (S@pPAN) cathodes exhibit the best cycle stability and rate performance at room temperature. The capacity retention is improved about 20% compared with conventional electrolyte after 200 cycles at 1C and the reversible capacity is maintained at about 1246.3 mAh g-1 even at 7C. This study indicates that DTFEC is a favorable additive in conventional liquid electrolytes for rechargeable lithium sulfur batteries.

Key words: lithium sulfur (Li-S) batteries, DTFEC, addictive, electrochemical performances