【摘要】 以石墨化中间相炭微球(MCMB)为前驱体,采用氧化、微膨胀法制备了微膨胀石墨电极材料(e-MC-MB);采用X射线衍射仪和扫描电镜表征样品的外貌、结构,并采用恒电流充放电测试和循环伏安法研究了微膨胀石墨电极在LiPF6有机电解液体系中的电化学行为。结果表明,微膨胀石墨材料有良好的球形形状,晶体参数La10、Lc和平均堆积碳层数与MCMB相比显著减小;平均层间距d(002)大于石墨材料,在0.411～0.418nm范围;首次充电在4.5～4.8V间存在明显的"电化学活化"现象,储能行为不同于传统石墨材料;在2.5～4.8V电压区间,放电比电容量达143.7F/g;将微膨胀石墨正极材料与石墨负极材料匹配,预计能得到高能量密度的锂离子电容器。更多还原

【Abstract】 A mild expanded graphite(e-MCMB) was prepared by oxidation and heat-treatment of MCMB.The morphology and structure of the samples were characterized by XRD and SEM analysis,respectively.The electrochemical behavior of the samples in LiPF6 electrolyte was studied using galvanostatic charge/discharge test and slow scan rate cyclic voltammograms.The results show and indicate that e-MCMB presented well spherical shape,the va-lues of crystallite parameters of e-MCMB such as La10,Lc and mean stack carbon layers(N) decreased significantly compared with that of MCMB.The mean interlayer distance(d(002)) was 0.411-0.418nm,which was larger than graphite′s.There was obvious phenomenon of "electricity activation" in the first charging potential of 4.5-4.8V(vs Li).The energy storage behavior of mild expanded graphite was different with that of graphite,and the specific capa-citance was 143.7F/g.The lithium ion capacitor with high energy density could be obtained by matching the expanded graphite anode material and graphite cathode material.更多还原