石墨烯和碳纳米管二元复合导电剂对LiNi0.5Co0.2Mn0.3O2锂离子电池性能的影响

Effect of binary composite conductive agent with graphene and carbon nanotube on performance of LiNi0.5Co0.2Mn0.3O2 lithium-ion battery

  • 摘要: 主要以石墨烯(Gen)、碳纳米管(CNTs)及其二者的复合材料石墨烯/碳纳米管(Gen/CNTs)为研究对象,将其以不同的含量、比例添加在LiNi0.5Co0.2Mn0.3O2中,制备了一系列软包电池。通过XRD、SEM、电化学性能等测试研究了不同导电剂与正极材料结合情况,以及导电剂含量配比对锂离子电池性能的影响。结果表明:电池的性能与导电剂含量密切相关,并且复合导电剂的性能优于单一导电剂。在石墨烯/碳纳米管比例相同的情况下,随着导电剂添加量增加,电池的内阻显著降低,放电容量、倍率性能、循环性能均得到改善。导电剂为1.5% Gen/CNT(3/7,质量比)时,0.2 C下放电比容量可达163.2 mAh/g,在5 C下放电比容量仍可达85.5 mAh/g,其循环性能也最好,1 C循环200次后,容量保持率可达103.12%。

     

    Abstract: In this paper, graphene (Gen), carbon nanotubes (CNTs) and their composite materials graphene/carbon nanotubes (Gen/CNTs) were added to LiNi0.5Co0.2Mn0.3O2 in different contents and proportions to prepare soft pack batteries. The combination between different conductive agents and anode materials and the content ratio of conductive agents on the performance of lithium-ion batteries were studied by XRD, SEM and electrochemical performance tests. Experimental results show that the performance of the battery is closely related to the content of the conductive agent, and the performances of the composite conductive agents are better than those of the single conductive agents. Under the same graphene/carbon nanotube ratio, the internal resistance of the battery is significantly reduced with the increasing amount of conductive agent, and the discharge capacity, rate performance and cycle performance are all improved. When the conductive agent is 1.5% Gen/CNT (3/7, w/w), the discharge specific capacity at 0.2 C can reach 163.2 mAh/g, and the specific discharge capacity can still reach 85.5 mAh/g at 5 C, with the best circulation performance. After 200 cycles at 1 C, the capacity retention rate can reach 103.12%.

     

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