氧化剂对磺化石墨烯负载聚苯胺复合材料结构与电化学性能的影响

EFFECT OF OXIDANTS ON STRUCTURE AND ELECTROCHEMICAL PERFORMANCE OF SULFONATED GRAPHENE SUPPORTED POLYANILINE COMPOSITES

以磺化石墨烯(sGNS)为基板材料,通过界面聚合方法制备出不同分级结构磺化石墨烯负载聚苯胺(sGNS/PANI)复合材料,并系统研究了氧化剂类型对复合材料的化学组成、形貌结构和超级电容特性的影响.结果显示,过硫酸铵为氧化剂合成的复合材料中PANI的产率和氧化程度最高,其形貌呈现出sGNS垂直生长PANI纳米短棒阵列结构,PANI的共轭程度和结晶性均较高,从而赋予复合材料高的比电容(497.3 Fg-1),以及良好的倍率特性和循环稳定性(2000次循环后比电容仅损失5.7%).当以三氯化铁为氧化剂时,复合材料中PANI的得率很低,并在sGNS表面形成较薄的包覆层,此时复合材料的比电容最低(228.5 Fg-1),但充放电循环性能较好(2000次循环后比电容的保持率为87.4%).当氧化剂为高锰酸钾时,复合材料中PANI以团聚态颗粒无规堆积在sGNS表面,PANI以无定型结构存在,其比电容虽然较高(419.6 F g-1),但其倍率特性和充放电循环性能较差(2000次循环后比电容损失19.9%).

The sulfonated graphene supported polyaniline composites（sGNS/PANI） with different hierarchical structures were synthesized successfully via an interfacial polymerization method using sGNS as the substrate,and the influence of oxidant type on chemical composition,morphological structure and supercapacitive performance of the composites was investigated systematically.The results showed when ammonium persulfate（APS） was used as the oxidant the PANI had the highest yield and degree of oxidation.The hierarchical composite of sGNS-supported vertically aligned PANI nanorod arrays was formed,and the PANI nanorod arrays possessed higher degree of conjugation and crystallinity,thus the composite exhibited high specific capacitance（497 Fg^-1）,excellent rate capability and cycling stability（5.7% capacitance loss after 2000 cycles）.As oxidant was FeCl3,the PANI had a very low productivity,and the PANI was coated onto the surface of sGNS and formed a thin film.And the composite possessed the lowest specific capacitance（228.5 Fg^-1）,but charge-discharge cycle performance was rather good（87.4% retention rate of capacitance after 2000 cycles）.When KMnO4 was used,the PANI with agglomerated particles randomly accumulated on the surface of sGNS,and the PANI displayed amorphous structure.The composite showed a relatively high specific capacitance of 419.6 Fg^-1,but the rate capability and cycling stability（19.9% capacitance loss after 2000 cycles） were poor.