方形微粒氧化铁/石墨烯复合材料的合成及其电化学性能研究

Synthesis of Cubic Fe2O3/Graphene Composite and Its Electrochemical Performances

合成了一种方形微粒的氧化铁/石墨烯(Fe2O3/GO)复合材料,在高倍扫描电镜下观察,氧化铁呈现方形的小颗粒,并且均匀地与片状石墨烯复合在一起.能谱测试显示,该复合材料中只有铁、氧、碳3种元素,没有杂质出现,并且各元素分布均匀.得益于其复合结构, Fe2O3/GO复合材料表现出了很好的电化学性能.在0.2 A·g^-1的电流密度下,能够释放出高达1 094/1 377 mAh·g^-1的首次充放电容量,在1.0 A·g^-1下对其进行循环稳定性测试,在100次循环后,其充放电容量仍高达686/693 mAh·g^-1.经分析,复合结构中的石墨烯网络起到了高速电子传递和应力缓冲器的作用,很好地抑制了材料的体积效应,从而防止电极在循环过程中的材料粉化脱落,有效提高了材料的电化学性能.

Cubic Fe2 O3/GO composite is successfully synthesized in this work. The as-prepared material exhibits the phase of Fe2 O3 without any other impure phase. The Fe2 O3 is observed by SEM with cubic particles and well composited with graphene. The EDS test shows that there are only iron, oxygen and carbon elements in the material, which are well distributed. Thus, cubic Fe2 O3 exhibits excellent electrochemical properties due to its special composite structure. The electrode can deliver initial charge/discharge capacities of 1 094/1 377 mAh·g^-1 at the current density of 0.2 A·g^-1. Furthermore, the high charge/discharge capacity of 686/693 mAh·g^-1 is maintained after 100 cycles at the current density of 1.0 A·g^-1. It is attributed to the graphene, which serves as fast electronic transfer network and buffer for stress concentration. It restrains the volumetric effect during repeated charge-discharge processes and stops the pulverization of the electrode to improve the electrochemical properties.