论文部分内容阅读
针对目前的锂离子电池负极材料存在比容量低、循环稳定性差等问题,本工作发展了简单、有效的方法合成氧化亚钴纳米粒子与石墨烯的复合材料(CoO/RGO).采用氧化石墨(GO)和Co(NO3)2作为原料,先用水热路线制备了前驱体,再将其在氮气气氛下热处理,最终得到CoO/RGO复合材料.存在于石墨烯表面的CoO纳米粒子可以有效地阻止石墨烯片层的聚集,同时石墨烯片层的相互连接能够形成三维的空间网络,提高复合材料的导电性.将合成的CoO/RGO复合材料作为负极,以锂片作为正极,组装成纽扣电池.电化学测试表明,在电流密度为100 mA·g~(-1)的条件下,初始比容量放电比容量高达1312.6 mAh·g~(-1),在10000 mA·g~(-1)的大电流密度下,经过300圈循环后,其比容量仍然可以达到557.4 mAh·g~(-1).这表明CoO/RGO复合材料具有高的比容量、优异的倍率性能及循环稳定性,这归因于3D网状结构能够避免在锂离子的嵌入/脱出过程中材料的结构被严重破坏.
In view of the low specific capacity and poor cycle stability of the negative electrode material for lithium ion batteries, a simple and effective method has been developed for the synthesis of cobalt oxide nanoparticles and graphene composite materials (CoO / RGO) GO) and Co (NO3) 2 as raw materials, the precursors were first prepared by hydrothermal route and then annealed under a nitrogen atmosphere to obtain CoO / RGO composites. CoO nanoparticles present on graphene surface can effectively Prevent the aggregation of the graphene sheets, and at the same time, the interconnection of the graphene sheets can form a three-dimensional space network and improve the conductivity of the composite material. The synthesized CoO / RGO composite material is taken as a negative electrode and the lithium plate is used as a positive electrode, The results of electrochemical tests show that the initial specific capacity discharge capacity is up to 1312.6 mAh · g -1 under the current density of 100 mA · g -1, ), The specific capacity of the composite can reach 557.4 mAh · g -1 after 300 cycles, which shows that the CoO / RGO composite has high specific capacity, excellent rate performance and cycle stability , Due to the 3D mesh structure that can be avoided in lithium Structural sub embedding / extraction process material is seriously damaged.