具有分级结构的Co_3O_4绣球花状微米球的构筑及其锂离子电池负极性能研究

Facile fabrication of Co_3O_4 hydrangea-like microspheres with hierarchical structure and research on their enhanced performance in lithium ion batteries

采用溶剂热法合成了绣球花状Co_3O_4纳米材料,并利用扫描电子显微镜和X射线衍射仪进行了微观形貌和结构的表征,结果显示样品的形貌为4~6μm绣球花状分级结构微米球,结晶良好,无杂相生成。该绣球花状Co_3O_4纳米材料用做锂离子电池负极材料时表现出很高的可逆比容量和良好的循环性能。在300 m A/g电流密度下,首次放电比容量达1 508 m A·h/g,经过20次循环可逆比容量为1 300 m A·h/g。其良好的电化学性能归功于绣球花状Co_3O_4材料的独特形貌,其多级结构能够缩短锂离子的传输路径,并且拥有足够大的孔隙,来适应和缓解电极材料在循环过程的体积效应。

In this paper, the hydrangea-like Co3O4 nanomaterials have been developed using solvothermal method, and the morphology and microstructure analysis have been identified by the SEM and XRD. The results showed that the morphology of sample was 4-6μm hydrangea like microspheres with hierarchical structure, well-crystallized and without any impurity phase. When applied as anode material in lithium ion battery, hydrangea-like Co3O4 hierarchical structure demonstrated high reversible capacity and good recyclability. The Co3O4 anode could deliver initial discharge capacity as high as 1508 mA· h/g at a current density of 300 mA/g, and had excellent reversible capacity of 1300 mA · h/g after 20 cycles. The unique morphology of the as-synthesized hydrangea-like C%04 nanomaterials enhances their electrochemical performance. The peculiar hierarchical structure of Co3O4 provides a short path for Li^＋ ion diffusion, and enough free space to accommodate the large volume changed during cycling.