Carbon-encapsulated Fe3O4 composites were successfully fabricated via hydrothermal method and ex- amined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The Fe3O4@C nanocomposite as an anode material with novel structure demonstrated excellent electrochemical performance, with enhanced specific reversible current density of 50 mA/g capacity （950 mAh/g at the after 50 cycles）, remarkable rate capability （more than 650 mAh/g even at the current density of 1,000 mAJg） and good cycle ability with less capacity fading （2.4 % after 50 cycles）. Two factors have been attributed to the ultrahigh electrochemical perfor- mance： Firstly, the 30- to 50-nm spherical structure with a short diffusion pathway and the amorphous carbon layer could not only provide extra space for buffering the volumetric change during the continuous charging-dis- charging but also improve the whole conductivity of the Fe3O4@C nanocomposite electrode; secondly, the syner- gistic effects of Fe304 and carbon could avoid Fe304 direct exposure to the electrolyte and maintain the structural stabilization of Fe3O4@C nanocomposite. It was suggested that the Fe3O4@C nanocomposite could be suitable as analternative anode for lithium-ion batteries with a high ap- plication potential.
采用原位聚合法制备锡酸钴（Co2SnO4）/聚苯胺（PANI）复合负极材料,用XRD、SEM分析物相结构与形貌,对复合材料进行恒流充放电、循环伏安及电化学阻抗谱测试。添加PANI可缓解Co2SnO4在充放电过程中的体积膨胀效应,使Co2SnO4/PANI体系的电子导电率与循环性能得到改善。以100 m A/g的电流在0.01--3.00 V循环,Co2SnO4/PANI复合材料的首次放电比容量为1 234.11 m Ah/g,第80次循环的放电比容量为817.36 m Ah/g。
TiO2-coated SnO2 （TCS） hollow spheres, which are new anode materials for lithium ion （Li-ion） batteries, were prepared and characterized with X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, cyclic voltammetry （CV）, and galvanostatic charge/discharge tests. The results obtained from XRD, SEM, and TEM show that TiO2 can be uniforrrdy coated on the surface of SnO2 hollow spheres with the assistance of anionic surfactant. The cyclic voltammograms indicate that both TiO2 and SnO2 exhibit the activity for Li-ion storage. The charge/discharge tests show that the prepared TCS hollow spheres have a higher reversible coulomb efficiency and a better cycling stability than the uncoated SnO2 hollow spheres.
YI JinLI XiaopingHU ShejunLI WeishanZENG RonghuaFU ZhaoCHEN Lang
