用真空抽滤氧化石墨(GO)与聚苯胺(PANI)纳米纤维的混合分散溶液,流动组装得到自支撑GO/PANI复合薄膜,再利用气态水合肼还原其中的GO,最后重新氧化和掺杂还原态PANI,制备了自支撑石墨烯(GN)/PANI薄膜.扫描电子显微镜(SEM)结果显示,GN/PANI薄膜为层状结构,且PANI纳米纤维均匀插层于GN片间.PANI纳米纤维在复合薄膜中的存在有效增大了GN之间的层间距,有利于电解液离子与GN充分接触.GN的高电导性则有利于PANI氧化还原过程中的电荷传输.电化学测试表明,GN/PANI薄膜在1mol·L^-1HCl电解液中具有良好的电化学电容性能,在0.1A·g^-1的电流密度下的比容量为495F·g^-1,在3A·g^-1时为313F·g^-1.经过2000次连续充放电,其具有90%的电容保持率,表明该复合材料具有良好的电化学稳定性.
A freestanding film composed of graphene (GN) sheets and polyaniline (PANI) nanofibres was fabricated by reducing a graphite oxide (GO)/PANI precursor that was prepared by flow-directed assembly from a complex dispersion of GO and PANI. This was followed by reoxidation and redoping of the reduced PANI in the composite to restore the conducting PANI structure. A scanning electron microscope (SEM) image indicates that the GN/PANI film is a layered structure with PANI nanofibres uniformly sandwiched between the GN sheets. In the composite film, the PANI nanofibres can increase the basal spacing between GN sheets. Therefore, electrolyte ions have better accessibility to the GN surfaces. The GN sheets can act as current collector to decrease the inner resistance of the electrode, which is convenient for electronic and ionic transportation during the redox process of PANI. The electrochemical properties of the freestanding GN/PANI film were estimated by cyclic voltammetry and galvanostatic charge-discharge in 1 mol. L^-1 HCl electrolyte, Electrochemical analysis demonstrates that the as-prepared GN/PANI film has good capacitive behavior. The specific capacitance was 495 F. g^-1 at a current density of 0.1 A. g^-1 and the capacitance was 313 F·g^-1even at a current density of 3 A.g^-1 After 2000 cycles, the capacitance of the GN/PANI film decreases 10% of its initial capacitance, which demonstrates that the GN/PANI electrode has good cycle stability.