Electrochemical performance of MCMB/(AC+LiFePO_4) lithium-ion capacitors  

作　　者：PING LiNa ZHENG JiaMing SHI ZhiQiang QI Jie WANG ChengYang 

机构地区：[1]Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering and Technology,Tianjin University [2]Laboratory of Advanced Energy Materials and Devices,College of Materials Science and Engineering,Tianjin Key Laboratory of Fiber Modification and Functional Fiber,Tianjin Polytechnic University

出　　处：《Chinese Science Bulletin》2013年第6期689-695,共7页

基　　金：supported by the National Natural Science Foundation of China (51172160,50902102);the National High Technology Research and Development Program of China (2011AA11A232);the National Basic Research Program of China (2012CB720302)

摘　　要：Lithium-ion capacitors(LICs) were fabricated using mesocarbon microbeads(MCMB) as a negative electrode and a mixture of activated carbon(AC) and LiFePO4 as a positive electrode(abbreviated as LAC).The phase structure and morphology of LAC samples were characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM).The electrochemical performance of the LICs was studied using cyclic voltammetry,charge-discharge rate measurements,and cycle performance testing.A LIC with 30 wt% LiFePO4 was found to have the best electrochemical performance with a specific energy density of 69.02 W h kg-1 remaining at 4 C rate after 100 cycles.Compared with an AC-only positive electrode system,the ratio of practical capacity to theoretical calculated capacity of the LICs was enhanced from 42.22% to 56.59%.It was proved that adding LiFePO4 to AC electrodes not only increased the capacity of the positive electrode,but also improved the electrochemical performances of the whole LICs via Li+ pre-doping.Lithium-ion capacitors （LICs） were fabricated using mesocarbon microbeads （MCMB） as a negative electrode and a mixture of activated carbon （AC） and LiFePO4 as a positive electrode （abbreviated as LAC）. The phase structure and morphology of LAC samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）. The electro- chemical performance of the LICs was studied using cyclic voltammetry, charge-discharge rate measurements, and cycle perfor- mance testing. A LIC with 30 wt% LiFePO4 was found to have the best electrochemical performance with a specific energy den- sity of 69.02 W h kg-1 remaining at 4 C rate after 100 cycles. Compared with an AC-only positive electrode system, the ratio of practical capacity to theoretical calculated capacity of the LICs was enhanced from 42.22% to 56.59%. It was proved that adding LiFePO4 to AC electrodes not only increased the capacity of the positive electrode, but also improved the electrochemical perfor- mances of the whole LICs via Li＋ pre-doping.

关 键 词：电化学性能 离子电容器 MCMB LAC 氟化锂 场发射扫描电子显微镜 EPO 循环伏安法 

分 类 号：TM53[电气工程—电器]