锂离子电池Co(OH)_2/C复合负极材料的研究

Study on Co(OH)_2/C composite anode material for lithium ion batteries

采用沉淀-水热法制备Co(OH)_2/C复合材料.通过TG-DSC、XRD和显微镜照片分析材料的组成、结构和形貌,通过循环充放电研究材料的循环性能,分析充放电曲线、微分容量曲线和交流阻抗探讨材料的嵌/脱锂机理.结果表明:Co(OH)_2/C复合材料首次可逆比容量达617m Ah/g,循环效率为84.4%;20次循环后,Co(OH)_2/C复合材料可逆比容量仍有298m Ah/g,循环效率为96.4%,容量保持率为48.3%,而Co(OH)_2材料分别只有244m Ah/g、94.0%和38.0%,石墨可有效改善材料的循环性能.

Co（OH）2/C composites were prepared by precipitation-hydrothermal method. The components and structure were analyzed by TG-DSC and XRD and Microscope photos. The cycle performance was studied by cycle charge-discharge test, and the lithium insertion-extraction behavior was studied by charge and discharge curves, differential capacity curves and AC impedance. The results show that the initial reversible specific capacity of Co（OH）2/C composite was 617 m Ah/g, and the coulombic efficiency was 84.4%. After 20 cycles, the reversible specific capacity of Co（OH）2/C was 298 m Ah/g, the coulombic efficiency was 96.4%, the capacity keep rate was 48.3%, but it was only 244 m Ah/g and 94.0% and38.0% of the pure Co（OH）2material respectively. The cycle performance of material was improved by doping C obviously.