In situ polymerization and reduction to fabricate gold nanoparticle‐incorporated polyaniline as supercapacitor electrode materials

Nanocomposites of gold nanoparticles and polyaniline are synthesized by using HAuCl₄ and ammonium peroxydisulfate as the co‐oxidant involving in situ polymerization of aniline and in situ reduction of HAuCl₄. Through these in situ methods, the synthesized Au nanoparticles of ca. 20 nm embedded tightly and dispersed uniformly in polyaniline backbone. With the Au content in composite increasing from 4.20 to 24.72 wt.%, the specific capacitance of the materials first increased from 334 to 392 F g^?1 and then decreased to 298 F g^?1. Based on the real content of PANI in composite material, the highest specific capacitance is calculated to be 485 F g^?1 at the Au amount of 19.15 wt.%, which remains 55.6% after 5000 cycles at the current density of 2 A g^?1. Finally, the asymmetric supercapacitor of AuNP/PANI||AC and the symmetric supercapacitor of AuNP/PANI||AuNP/PANI are assembled. The asymmetric supercapacitor device shows a better electrochemical performance, which delivers the maximum energy density of 7.71 Wh kg^?1 with power density of 125 W kg^?1 and maximum power density of 2500 W kg^?1 with the energy density of 5.35 Wh kg^?1.