Revealing dual capacitive mechanism of carbon cathode toward ultrafast quasi-solid-state lithium ion capacitors

作     者：Kangyu Zou Peng Cai Xinglan Deng Baowei Wang Cheng Liu Jiayang Li Hongshuai Hou Guoqiang Zou Xiaobo Ji Kangyu Zou;Peng Cai;Xinglan Deng;Baowei Wang;Cheng Liu;Jiayang Li;Hongshuai Hou;Guoqiang Zou;Xiaobo Ji

作者机构：College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China College of Metallurgy and Chemical EngineeringJiangxi University of Science and TechnologyGanzhou 341000China 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2021年第30卷第9期

页      面：209-221页

核心收录：

学科分类：0820[工学-石油与天然气工程] 081702[工学-化学工艺] 080801[工学-电机与电器] 0808[工学-电气工程] 0817[工学-化学工程与技术] 08[工学] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 

基　　金：financially supported by the National Key Research and Development Program of China (2018YFC1901605) the National Natural Science Foundation of China (52004338) the Hunan Provincial Natural Science Foundation of China (2020JJ5696) the Guangdong Provincial Department of Natural Resources (2020-011) the Fundamental Research Funds for the Central Universities of Central South University (2020zzts058) 

主　　题：Capacitive mechanism Carbon cathode Carbonyl group Quasi-solid-state Lithium ion capacitors 

摘      要：High-performance lithium ion capacitors(LICs) have been seriously hindered by the very low capacity and unclear capacitive mechanism of carbon ***,after the combination of experimental results and theoretical calculations,it is found that the critical pore size of 0.8 nm for PF_6~-ion adsorption decreases strong interactive repulsion of electrons and largely reduces adsorption energy barrier,which greatly improves the charge accommodation capacity in electrical double-layer *** importantly,the chemical-bond evolution process of C=O group has been firstly revealed by X-ray photoelectron spectroscopy(XPS),indicating that the introduction of C=O group can provide abundant redox active sites for PF_6~-ion adsorption accompanied with enhanced pseudocapacitive *** to the synergistic effect of dual capacitive mechanism,porous carbon sheet(PCS) cathode shows a reversible specific capacity of 53.6 mAh g^(-1) even at a high current density of 50 A g^(-1).Significantly,the quasisolid-state LIC manifests state-of-the-art electrochemical performances with an integrated maximum energy density of 163 Wh kg^(-1) and an outstanding power density of 15,000 W kg^(-1).This elaborate work promotes better fundamental understanding about capacitive mechanism of PF_6~-ion and offers a rational dual-capacitive strategy for the design of advanced carbon cathodes.