Iron oxide encapsulated in nitrogen-rich carbon enabling high-performance lithium-ion capacitor  

核壳结构Fe3O4@NC复合材料的储锂性能研究及锂离子电容器构建

作　　者：Jinhua Zhou Shuchi Xu Qi Kang Lu Ni Ningna Chen Xiaoge Li Chunliang Lu Xizhang Wang Luming Peng Xuefeng Guo Weiping Ding Wenhua Hou 周锦华;徐舒迟;康琪;倪璐;陈宁娜;李小阁;陆春良;王喜章;彭路明;郭学锋;丁维平;侯文华(Key Laboratory of Mesoscopic Chemistry of MOE,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China;Department of Polymer Science and Engineering,Shanghai Key Laboratory of Electrical Insulation and Thermal Aging,Shanghai Jiao Tong University,Shanghai 200240,China;Analytical Testing Center,Yangzhou University,Yangzhou 225009,China)

机构地区：[1]Key Laboratory of Mesoscopic Chemistry of MOE,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China [2]Department of Polymer Science and Engineering,Shanghai Key Laboratory of Electrical Insulation and Thermal Aging,Shanghai Jiao Tong University,Shanghai 200240,China [3]Analytical Testing Center,Yangzhou University,Yangzhou 225009,China

出　　处：《Science China Materials》2020年第11期2289-2302,共14页中国科学（材料科学（英文版）

基　　金：financial support of the National Natural Science Foundation of China(21773116);the Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP,20130091110010);the Natural Science Foundation of Jiangsu Province(BK2011438);the National Science Fund for Talent Training in Basic Science(J1103310)。

摘　　要：Lithium-ion capacitors(LICs)could combine the virtues of high power capability of conventional supercapacitors and high energy density of lithium-ion batteries.However,the lack of high-performance electrode materials and the kinetic imbalance between the positive and negative electrodes are the major challenge.In this study,Fe3O4 nanoparticles encapsulated in nitrogen-rich carbon(Fe3O4@NC)were prepared through a self-assembly of the colloidal Fe OOH with polyaniline(PANI)followed by pyrolysis.Due to the well-designed nanostructure,conductive nitrogen-rich carbon shells,abundant micropores and high specific surface area,Fe3O4@NC-700 delivers a high capacity,high rate capability and long cycling stability.Kinetic analyses of the redox reactions reveal the pseudocapacitive mechanism and the feasibility as negative material in LIC devices.A novel LIC was constructed with Fe3O4@NC-700 as the negative electrode and expanded graphene(EGN)as the positive electrode.The wellmatched two electrodes effectively alleviate the kinetic imbalance between the positive and negative electrodes.As a result,Fe3O4@NC-700//EGN LIC exhibits a wide operating voltage window,and thus achieves an ultrahigh energy density of 137.5 W h kg^-1.These results provide fundamental insights into the design of pseudocapacitive electrode and show future research directions towards the next generation energy storage devices.锂离子电容器继承了超级电容器高功率性能和锂离子电池高能量密度两者的优点.然而,高电化学性能电极材料的短缺以及正负电极材料动力学的不匹配是构筑高能量/高功率密度锂离子电池遇到的最大挑战.我们通过简单的溶液组装和煅烧法得到了具有核壳结构的Fe3O4@NC复合材料.首先,研究了不同热解温度得到的Fe3O4@NC样品的储锂性能.结构单元纳米化和丰富的微孔使得Fe3O4@NC-700具有大比表面积,同时暴露出更多的活性位点,缩短了离子传输路径,表现出特殊的赝电容行为,从而显著提高了储锂动力学.除此之外,N-掺杂的碳壳提供了较高的电子导电性并保证了在循环测试中的结构完整性.以Fe3O4@NC-700为负极,膨胀石墨烯EGN为正极,1 mol L^-1Li PF6为电解液,组装成锂离子电容器.受益于正负电极相配的动力学以及Fe3O4@NC-700和EGN两者的协同优势,Fe3O4@NC-700//EGN杂化离子电容器获得了较宽的工作电压窗口(1.0–4.5 V),比能量最高可达137 W h kg^-1,比功率最高可达8.2 k W kg^-1,且循环稳定性出色.本工作可为下一代兼具高比能量和高比功率的新型混合能源存储系统的设计提供启示.

关 键 词：FE3O4 CARBON N doping expanded graphene lithium-ion capacitor 

分 类 号：TB33[一般工业技术—材料科学与工程] TM53[电气工程—电器]