Energy Storage Science and Technology ›› 2018, Vol. 7 ›› Issue (2): 240-247.doi: 10.12028/j.issn.2095-4239.2017.0164

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Development of hybrid electrochemical energy storage device based on LiFePO4 and activated carbon

ZHANG Shiming1,2, CHE Haiying1, YANG Ke1, YANG Xinrong1, ZHENG Dan2, MA Zifeng1,2   

  1. 1Department of Chemical Engineering, Shanghai Electrochemical Energy Device Research Center, Shanghai Jiao Tong University, Shanghai 200240, China; 2 Shanghai Sinopoly Jiahua Battery Technology Co., Ltd., Sinopoly Battery Research Center, Shanghai 200241, China
  • Received:2017-11-20 Revised:2018-01-25 Online:2018-03-01 Published:2018-03-01

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Abstract:

 Mixed bi-material composite electrode based on LiFePO4 and activated carbon (AC) for hybrid electrochemical energy storage (EES) devices was prepared. The EES devices have been constructed by choosing submicron graphite as anode material and optimizing LiFePO4/AC composites with different mass ratios as the cathode. The results showed that binders had great influence on the capacitive properties of AC, and LA133 as one of the water-based binders should be better choice than oily adhesives. Furthermore, the prepared LiFePO4/AC composite cathodes emerged the dual characteristics of capacitor and battery. As the 40% (weight ratio) of LiFePO4 in the composite cathode, the lithium-ion capacitor could reveal high specific energy which is about 4 times comparing with that of AC/AC supercapacitor (about 40 W·h·kg-1) by computation of the total active materials. Also, it could achieve the fast charge-discharge at 10 C rate. In addition, both of the two devices exhibited the similar cyclability with about 75% of capacity retention after about 5000 cycles.

Key words: lithium-ion capacitor, submicron graphite, LiFePO4/AC composite cathode, water-based binder, fast-charging, long-life