Pickering乳液模板法制备石墨烯/聚苯胺空心微球及其在超级电容器中的应用

Preparation of Graphene/Polyaniline Hollow Spheres via Pickering Emulsion Polymerization and Its Application in Supercapacitors

以离子液体(IL-NH2)对氧化石墨烯进行修饰,得到离子液体修饰的还原氧化石墨烯(rGO-IL),将其作为颗粒乳化剂稳定含有苯胺单体的油相,制备稳定均匀的Pickering乳液,然后通过引发苯胺单体聚合得到石墨烯/聚苯胺空心微球。离子液体的引入不仅可以调节Pickering乳化剂的润湿性,还能避免降低材料的电导率。通过控制IL-NH2对石墨烯的修饰程度调节了rGO-IL的润湿性,并探究了rGO-IL的润湿性、浓度以及乳化时的油水比对Pickering乳液性质的影响。利用超景深三维显微镜观察了rGO-IL稳定的Pickering乳液状态;利用傅里叶变换红外光谱仪、拉曼光谱仪和扫描电子显微镜对所得石墨烯/聚苯胺空心微球的化学结构和形貌进行了观察;利用循环伏安法与恒流充放电法对空心微球的电容性能进行了探究。结果显示,石墨烯/聚苯胺空心微球比电容可以达到451.8 F/g,是二维石墨烯/聚苯胺材料的近2倍(227 F/g);另外空心微球表现出良好的倍率性能,当电流密度从0.5 A/g增加至10 A/g时,其电容保持率高达92.4%,远高于二维材料的46.5%。

A kind of graphene/polyaniline hybrid hollow capsule was fabricated via Pickering emulsion using ionic liquid-modified reduced graphene oxide(rGO-IL)Pickering emulsifier.In our strategy,rGO-IL was first prepared and employed to stabilize the oil phase containing aniline to prepare the stable and uniform Pickering emulsion.Upon the polymerization of aniline at the oil/water interface,ionic liquid functionalized graphene/polyaniline hollow spheres(rGO-IL/PANI HS)were obtained.The functionalization of rGO by ionic liquid can not only adjust the wettability of rGO,but also avoid reducing its conductivity.The wettability of rGO-IL is adjusted by adjusting the modification degree of graphene by IL-NH2.The influence of wettability and concentration of rGO-IL as well as oil-water ratio on the properties of Pickering emulsion was explored.At the same time,the effect of aniline addition on the electrochemical performance of rGO-IL/PANI HS was also studied.The Pickering emulsions stabilized by rGO-IL were observed by super deep scene 3D microscope.According to the emulsion droplet morphology and particle size distribution,the optimal preparation conditions were obtained.The chemical structure and morphology of rGO-IL/PANI HS were analyzed by FT-IR,Raman spectrum and scanning electron microscope.The results show that the final product prepared from the rGO-IL-stabilized Pickering emulsion has spherical shape,and an obvious hollow structure could be observed from the breakage.The capacitance performance of rGO-IL/PANI HS was explored by cyclic voltammetry and galvanostatic charge-discharge.The specific capacitance of rGO-IL/PANI HS is able to reach a maximum of 451.8 F/g,which is nearly double that of two-dimensional rGO-IL/PANI materials(227 F/g).In addition,the prepared rGO-IL/PANI HS also shows excellent rate performance.When the current density is increased from 0.5 A/g to 10 A/g,the capacitance retention rate of rGO-IL/PANI HS is as high as 92.4%,much higher than 46.5%of two-dimensional materials.