石墨烯-四氧化三铁微球复合材料的制备及锂离子电池负极性能

Preparation of Graphene-Fe_3O_4 Microspheres Composites as Anode of Lithium Ion Batteries

采用水热合成法制备了Fe_3O_4微球,并基于静电引力自组装机制,合成了石墨烯-Fe_3O_4微球复合材料(GEFe_3O_4).Fe_3O_4微球在石墨烯表面均匀分布,且实现了石墨烯对Fe_3O_4微球的部分包覆.电化学测试结果表明,在92.6m A/g电流密度下,Fe_3O_4微球的首次放电容量为938.3 m Ah/g,经30次循环,其放电容量衰减为192.5 m Ah/g;GE-Fe_3O_4的首次放电容量为840 m Ah/g,第30次循环的放电容量达803.5 m Ah/g;电流密度升至463 m A/g,经50次循环,GE-Fe_3O_4的放电容量仍有306.6 m Ah/g.与单纯Fe_3O_4微球相比,GE-Fe_3O_4复合材料的锂离子电池负极性能获得显著改善.

Fe3O4 microspheres were prepared by a facile hydrothermal method and Graphene-Fe3O4 microspheres composites （GE-FFe3O4 ） was obtained based on static self-assemble mechanism in this paper. Fe3O4 microspheres distributed uniformly on the graphene sheets and part of them were wrapped by the graphene. The anode performances of the prepared materials were measured by constant charge-discharge method. The initial discharge capacity of Fe3O4 microspheres was 938.3 mAh/g at the current density of 92.6 mA/g and this value would decay to 192.5 mAh/g after 30 cycles. However, GE-Fe3O4 could deliver 840 mAh/g for the initial discharge capacity and 803.5 mAh/g for the 30th cycle. When the current density was increased to 463 mA/g, the discharge capacity of GE-Fe3O4 still can retain at 306.6 mAh/g after 50th cycle. Compared with pristine Fe304 microspheres, the lithium ion battery anode performance of GE-Fe3O4 has been improved greatly due to the exist of graphene in the electrode.