石墨烯包覆规整四硫化钒锂离子电池负极材料的制备及性能

Synthesis and Characterization of Graphene Coated Vanadium Sulfide Anode Materials in Lithium Ion Batteries

以十六烷基三甲基溴化铵(CTAB)修饰的氧化石墨烯(GO)为载体,采用水热法原位生长石墨烯包覆四硫化钒(VS4/rGO)复合材料.通过X线衍射仪(XRD)、X线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等一系列手段对材料晶体结构及形貌进行了表征,并将材料应用于锂离子电池负极材料,进行详细的电化学性能测试.研究结果表明:制备的四硫化钒(VS4)纳米粒子颗粒尺寸规整,石墨烯包覆完整均匀,形成了稳定的三维包覆结构.此结构的复合材料可以使纳米尺寸的VS4粒子和导电性能优异的石墨烯纳米片接触良好,合理释放活性材料充放电过程中的膨胀,并大大缩短Li+扩散距离.基于上述优势,制备的复合材料具有优异的充放电循环性能(约800mAh·g^-1,52mA·g^-1下循环50次),并兼顾了良好的倍率性能.

A facile in-situ hydrothermal approach has been developed to synthesis reduced graphene oxide (rGO) coated vanadium sulfide (VS4 )composite (labeled as VS4 /rGO) with the carriers of hexadecyl trimethylammonium bromide (CTAB) modifide GO.The crystal structure and morphology of this material were characterized by X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM) and transmission electron microscopy (TEM),and the electrochemical performance of VS 4/rGO acted as anode materials in lithium ion batteries was tested in detail.The results showed that the as-prepared vanadium sulfide nanoparticles are of similar sizes,the graphene are totally and uniformly coated on VS 4,and they formed a stable three-dimensional structure.This typical structure guaranteed an intimate contact between the nano-sized VS 4 particles and the graphene nanosheets with an excellent conductivity,reasonably release expansion in the charging and discharging process of the active materials,greatly shortened the diffusion distance of Li +.Based on the above advantages,the prepared composites owned an excellent charge-discharge cycle performance (about 800mAh·g^-1 ,50 cycles at 52 mA·g^-1 ),and outstanding rate capability into account.