储能科学与技术 ›› 2021, Vol. 10 ›› Issue (2): 491-496.doi: 10.19799/j.cnki.2095-4239.2020.0339

• 储能材料与器件 • 上一篇    下一篇

正负极质量非对称设计对超级电容器性能的影响研究

凤睿1(), 卢海1(), 刘心毅1, 李浩2, 李祥元2   

  1. 1.西安科技大学材料科学与工程学院,陕西 西安 710054
    2.西安合容新能源科技有限公司,陕西 西安 710200
  • 收稿日期:2020-10-16 修回日期:2020-11-09 出版日期:2021-03-05 发布日期:2021-03-05
  • 作者简介:凤睿(1996—),女,硕士研究生,研究方向为新能源材料与器件,E-mail:1875470869@qq.com|卢海,副教授,研究方向为新能源材料与器件,E-mail:lhxust@126.com
  • 基金资助:
    国家自然科学基金项目(51604221)

Study on effect of an asymmetric design of the mass on the cathode and anode on supercapacitor performance

Rui FENG1(), Hai LU1(), Xinyi LIU1, Hao LI2, Xiangyuan LI2   

  1. 1.College of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, Shaanxi China
    2.Xi'an Herong New Energy Technology Co. Ltd. , Xi'an 710200, Shaanxi, China
  • Received:2020-10-16 Revised:2020-11-09 Online:2021-03-05 Published:2021-03-05

摘要:

在咪唑型离子液体1-乙基-3-甲基咪唑四氟硼酸盐(EMIBF4)混配有机溶剂碳酸丙酸酯(PC)、碳酸二甲酯(DMC)的电解液中,通过调整正负极活性物质的质量比(P/N比),设计制作了一系列活性炭基超级电容器。采用恒流充放电、交流阻抗、循环伏安等测试技术对超级电容器的性能特性进行了评价,系统考察了这种非对称电极设计对超级电容器整体性能的影响。结果表明:较之传统对称型电容器(即P/N=1.0),适当增加正负极质量比有助于抑制电解液的高压氧化分解,提高电容器在3 V限压条件下的循环稳定性和小电流工作时的比电容值,但是会引起电容器放电电压降与等效串联内阻的增加。当P/N比为1.4时,电容器经10 mA电流充放电循环5000次后的电容保持率达90.4%,50 mA高倍率放电时比能量与比功率分别为9.95 W·h/kg和4480 W/kg,相比对称型电容器,虽然循环性能得到显著改善,但这是以牺牲功率特性为代价。该研究指出了非对称电极结构所具有的优点,同时也揭示了其存在的不足,因此这种设计方法难以兼顾电容器的整体性能提升。

关键词: 超级电容器, 非对称, 正负极质量比, 工作电压, 功率特性

Abstract:

A series of activated carbon-based supercapacitors were assembled in an electrolyte consisting of ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) mixed with propylene carbonate (PC) and dimethyl carbonate (DMC) by adjusting the mass ratio of the active materials on the cathode and anode (P/N ratio). The influence of the asymmetric electrode mass design on the overall performance of supercapacitors was investigated through galvanostatic charge/discharge, cyclic voltammetry, and electrochemical impedance spectroscopy. The results show that the oxidation decomposition of the electrolyte at high voltage is restrained. The 3V cycle stability and specific capacitance of the capacitor at low rates are improved by increasing the P/N ratio. However, it also leads to an increase in the discharge voltage drop and equivalent series resistance of the capacitor. The capacitance retention of the capacitor with the P/N ratio of 1.4 is 90.4% after 5000 cycles at 10 mA. Its specific energy and specific power are 9.95 W·h/kg and 4480 W/kg, respectively, at a discharge rate of 50 mA. This reflects better cycle performance but weaker power capability of the asymmetric capacitor than those of the symmetrical one. The research exhibits the merit of the asymmetric electrode structure but points out the difficulty in achieving an improved overall performance of the capacitor.

Key words: supercapacitor, asymmetric, P/N ratio, work voltage, power characteristic

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