物理化学学报 >> 2012, Vol. 28 >> Issue (07): 1733-1738.doi: 10.3866/PKU.WHXB201205092

电化学和新能源 上一篇    下一篇

以预锂化中间相碳微球为负极的锂离子电容器的电化学性能

平丽娜1, 郑嘉明1, 时志强2, 王成扬1   

  1. 1. 天津大学化工学院, 绿色合成与转换教育部重点实验室, 天津 300072;
    2. 天津工业大学材料科学与工程学院, 天津市改性与功能纤维重点实验室, 天津 300387
  • 收稿日期:2012-03-05 修回日期:2012-05-09 发布日期:2012-06-07
  • 通讯作者: 时志强, 王成扬 E-mail:cywang@tju.edu.cn; shizhiqiang@tjpu.edu.cn
  • 基金资助:

    国家自然科学基金(51172160, 50902102)和国家高技术研究发展计划项目(863) (2011AA11A232)资助

Electrochemical Performance of Lithium Ion Capacitors Using Li+-Intercalated Mesocarbon Microbeads as the Negative Electrode

PING Li-Na1, ZHENG Jia-Ming1, SHI Zhi-Qiang2, WANG Cheng-Yang1   

  1. 1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China;
    2. Tianjin Key Laboratory of Fiber Modification and Functional Fiber, College of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, P. R. China
  • Received:2012-03-05 Revised:2012-05-09 Published:2012-06-07
  • Contact: SHI Zhi-Qiang, WANG Cheng-Yang E-mail:cywang@tju.edu.cn; shizhiqiang@tjpu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51172160, 50902102) and National High Technology Research and Development Program of China (863) (2011AA11A232).

摘要:

以商品活性炭(AC)为正极, 预锂化中间相碳微球(LMCMBs)为负极, 组装成锂离子电容器(LICs). 用X射线衍射(XRD)对LMCMB 电极材料的晶体结构进行了表征和分析, 预锂化量(PIC)小于200 mAh·g-1 时,LMCMB电极材料基本保持了原始的石墨晶体结构. 利用三电极装置, 测试了充放电过程中LICs 的正、负极及整电容器的电压变化曲线. 以LMCMB为电极, 锂离子电容器负极的工作电压变低, 并且电压曲线更加平坦, 同时正极也可以利用到更低的电压区间. 对比锂离子电容器MCMB/AC, LMCMB/AC在比能量密度、循环性能和库仑效率电化学性能方面都得到了改善. 在电压区间2.0-3.8 V 下, 100 次循环后, 放电比容量的保持率从74.8%增加到100%, 库仑效率从95%增加到100%. LMCMB/AC电容器容量不衰退的直接原因是由于AC正极极化变小. 在2.0-3.8 V和1.5-3.8 V电压区间内, LMCMB/AC锂离子电容器的比能量密度分别可达85.6和97.9 Wh·kg-1.

关键词: 锂离子电容器, 非对称电容器, 中间相碳微球, 活性炭, 预锂化

Abstract:

Lithium ion capacitors (LICs) were fabricated using Li +-intercalated mesocarbon microbeads (LMCMBs) as the negative electrode and commercial activated carbon (AC) as the positive electrode. The phase structure of LMCMB electrodes was characterized by X-ray diffraction (XRD). LMCMB electrodes retain their original graphite crystal structure when the capacity induced by initial Li+ intercalation is less than 200 mAh·g-1. The charge-discharge performances of positive and negative electrodes and LICs were studied using a three-electrode cell. Using an LMCMB electrode as an anode, a stable working potential is obtained at lower voltage than using other electrodes, and the potential range of the positive electrode is extended to a lower range. The electrochemical performance of LMCMB/AC capacitors, including capacitance, cycle life, and efficiency, is improved compared with that of an MCMB/AC capacitor. The efficiency increases from less than 95% to nearly 100%, and the capacity retention is improved from 74.8% to nearly 100% for 100 cycles in a voltage range of 2.0 to 3.8 V. The stable capacity of LMCMB/AC capacitors with cycling is directly correlated to less polarization of AC during the charge storage process, which is caused in turn by the LMCMB negative electrode. Gravimetric energy densities as high as 85.6 and 97.9 Wh·kg-1 are obtained in voltage ranges of 2.0 to 3.8 V and 1.5 to 3.8 V, respectively.

Key words: Lithium ion capacitor, Hybrid capacitor, Mesocarbon microbead, Activated carbon, Li+ pre-doping

MSC2000: 

  • O646