功能型单层石墨烯的热剥离法制备及其超电容性能

Preparation of Functionalized Graphene Sheets by Thermal Exfoliation Approach and Their Electrochemical Supercapacitive Behavior

以氧化石墨(GO)作为前驱体,在两种不同热剥离温度下制备了两类功能型单层石墨烯.其中第一类功能型单层石墨烯通过在较低温度及空气气氛下热剥离GO制备;第二类功能型单层石墨烯通过在氮气保护下高温热剥离GO得到;利用氮气吸附-脱附方法测定了两类样品的比表面积,利用电化学测试方法分析了其超电容性能.结果表明,通过低温热剥离的方式即可以有效剥离GO;两类样品均具有较高的BET比表面积.低温热剥离GO所制备的功能型单层石墨烯在2 mol/L KOH体系中的最大比电容值约为220 F/g;而通过高温热剥离GO所制备的功能型单层石墨烯虽然同样具有较高的BET比表面积,但其最大比电容值下降至约150 F/g.这表明通过低温热剥离GO所制备的功能型单层石墨烯具有更优异的超电容性能.

Two kinds of functionalized graphene sheets were prepared via thermal exfoliation of graphite oxide（GO） precursor in two different routes.The first kind of functionalized graphene sheets was obtained by thermal exfoliation of GO at low temperature in air.The second kind was prepared by thermal exfoliation of GO at higher temperature in N2.The specific surface area of the two kinds of products was measured by using N2 adsorption-desorption analysis,while their supercapacitive behavior was evaluated by using electrochemical method.Results indicate that GO can be effectively thermally exfoliated even at relatively low temperature in air,and both kinds of products have high BET surface areas.Besides,the functionalized graphene sheets obtained via low temperature thermal exfoliation of GO have specific capacitance of about 220 F/g in aqueous KOH electrolyte;but those prepared via thermal exfoliation of GO at higher temperature in N2,with similar BET surface area,have lower specific capacitance of only about 150 F/g in the same electrolyte.This indicates that the first kind of functionalized graphene sheets has better supercapacitive behavior.