高性能锂离子电容器正极材料石墨烯-介孔炭复合物的制备及性能分析
摘要：目的 设计同时具有高质量活性和高体积活性的锂离子电容器(lithium-ion capacitor，LIC)复合正极材料。 方法 借助扫描电子显微镜、透射电子显微镜、康塔全自动比表面和孔径分析仪、四探针测试仪，通过实验分析了颗粒之间的微观形貌、堆叠方式、接触模式和界面特性对复合电极的电导率、电学性质的影响规律。 结果 将介孔活性炭(mesoporous activated carbon，MC)与单分散石墨烯/单壁碳纳米管杂化物(graphene/single-walled carbon nanotube hybrid，GNH)混合，紧密压缩制成锂离子电容器正极材料。GNH均匀地包裹在MC颗粒表面，与MC面对面接触，增大接触面积；而且GNH在MC颗粒之间形成均匀的三维导电网络，提供了快速的电子传导。另外，GNH具有开放结构，会优先吸附电解液离子，与MC界面间存在浓度梯度；同时，GNH具有较高的导电性，与导电性较差的MC界面间存在接触电势差效应。两者共同促使GNH和MC界面之间形成快速的离子和电子双传输路径，促进离子在MC内部的扩散，从而避免了高电流密度下因离子扩散缓慢而造成的容量损失。 结论 添加5% GNH提高了倍率性能，并且在不牺牲堆积密度的前提下同时提高质量和体积能量密度。
Abstract:Objectives The lithium-ion capacitor (LIC) composite cathode materials with both high mass activity and high volume activity were designed. Methods By scanning electron microscope, transmission electron microscope, Kanta fully automatic specific surface and pore size analyzer, and four-probe tester, the micromorphology, stacking mode, contact mode and interface characteristics between particles were analyzed for the impact of conductivity and electrical properties of composite electrodes. Results Mesoporous activated carbon (MC) and monodisperse graphene/single-walled carbon nanotube hybrid (GNH) were mixed, followed by compressing tightly to prepare the lithium-ion capacitor cathode material. GNH were uniformly wrapped around the surface of MC particles with face-to-face connection, which increases the contact area. Then, the even 3D conductive network constructed by GNH among the individual MC particles provided high electrical conductivity and accelerated electron conduction. In addition, GNH were located at the high ion concentration side due to their exohedral surface structure. Meanwhile, a contact potential difference effect existed between GNH (the easy conductive one) and MC (the poor conductive one). This produced rapid ion and electron dual transport channels at the interface between GNH and MC, and boosted ion diffusion in the porous structure inside MC particles. It will help avoid the loss of capacity from slow ion diffusion at higher current densities. Conclusions The addition of 5% GNH brings about outstanding rate performance, and higher mass and volumetric energy density, but does not reduce the packing density.
标题：高性能锂离子电容器正极材料石墨烯-介孔炭复合物的制备及性能分析
title:Preparation and Performance Analysis of High Performance Cathode Material Graphene-Mesoporous Carbon Composites for Lithium-Ion Capacitor
作者：韩秀秀, 魏少鑫, 汪剑, 崔超婕, 骞伟中
authors:Xiuxiun HAN, Shaoxin WEI, Jian WANG, Chaojie CUI, Weizhong QIAN
关键词：电化学储能,介孔活性炭,石墨烯,锂离子电容器,接触电势差,
keywords:electrochemical energy storage,mesoporous activated carbon,graphene,lithium-ion capacitor,contact potential difference,
发表日期：2024-06-30
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