石墨烯担载SnO2纳米复合材料的电化学性能研究

以热膨胀还原石墨烯为载体,采用超声辅助浸渍法制得一系列石墨烯担载SnO2纳米复合材料。利用X射线衍射(XRD)和透射电子显微镜(TEM)分析其微观结构,同时使用循环伏安法研究其相应电化学行为。结果表明:随浸渍时间延长,SnO2逐步占据石墨烯表面原有活性位(如含氧官能团和晶格缺陷),使其担载密度显著提高。但SnO2纳米颗粒对复合体系的赝电容贡献较小,同时其对石墨烯活性位具有掩蔽作用,反而导致石墨烯电容性能逐步下降。可见,石墨烯表面活性位对热膨胀石墨烯的电容性能起重要作用。

The electrochemical study on SnO2@graphene nano-composites

With thermally reduced graphene as the matrix,a series of SnO2@graphene nano-composites with different loading ratio were prepared by ultrasonic assisted impregnation approach.X-ray diffraction and transmission electron microscopy were employed to investigate the micro-structure,while cyclic voltammetry was introduced to study the electrochemical performance of as-prepared composites.The results showed that,with the prolongation of impregnation,the initial active sites(e.g.oxygen functionalities,lattice defects and dangling bonds) on the graphene surface were gradually substituted by SnO2 crystalline,and thus resulting in an increasing in the loading ratio of Sn.However,due to the minor contribution to pseudo-capacitance from SnO2 as well as the shielding effect to the active sites of graphene,the capacitance performance of the nano-composites was gradually decreased.Therefore,it is concluded that the initial active sites on the surface plaied a key role in improving the performance of graphene as supercapacitor electrode materials.