Polyaniline-mediated coupling of Mn3O4 nanoparticles on activated carbon for high-performance asymmetric supercapacitors

Abstract Manganese oxides are promising electrode materials for supercapacitors because of the low cost and high specific capacitance. But their application is still restricted by sluggish redox reaction rate and the poor conductivity. Herein, we report a novel composite in which Mn3O4 nanoparticles are strongly anchored on activated carbon through a thin conductive polyaniline layer as a coupling bridge. The polyaniline layer with crosslinked networks not only possesses good electrical conductivity, but also enables high interface compatibility for anchoring Mn3O4 nanoparticles. The Mn3O4 nanoparticles with interconnected porous structure have sufficient ion migration channels and large surface area. Therefore, the composite achieves a high specific capacitance of 352 F g−1 at 0.5 A g−1, remarkable rate performance of 248 F g−1 at 20 A g−1, and good cycle stability with 90% capacitance retention after 10,000 cycles at 5 A g−1. The assembled asymmetric supercapacitor exhibits a high energy density of 33.8 Wh kg−1. The study suggests that the low-cost and high-performance activated carbon/polyaniline/Mn3O4 has broad application prospects in electrochemical energy storage fields.