Hierarchical-graphene-coupled polyaniline aerogels for electrochemical energy storage

Abstract

Graphene oxide (GO) is one of the most popular materials for preparing aerogels as monolith electrodes for supercapacitors because of its promising mechanical property and relatively good conductivity after thermal reduction. However, low surface area and restacking of reduced graphene nanosheets still limit the performance of the supercapacitors based on GO-derived aerogels. In this work, graphene-coupled polyaniline (PANI) nanosheets (GO@PANI), which were synthesized through interfacial polymerization method, were used to co-assemble with GO towards hierarchical-graphene-coupled PANI aerogels by hydrothermal strategy. The resultant new hybrid aerogels exhibited a typical three-dimensional (3D) porous structure with rich graphene/PANI heterostructure and high specific surface area of up to 337 m2/g. As electrodes for symmetric and asymmetric all-solid-state supercapacitors, the aerogels delivered areal capacitances of up to 453 and 679 mF/cm2, respectively, which are superior to those of most GO- and/or PANI-derived aerogel-based supercapacitors. This excellent electrochemical performance can be attributed to the synergistic contribution of the local conductivity of graphene layers sandwiched between PANI layers and long-distance conductivity of 3D graphene frameworks. The developed hierarchical-assembly method can be widely used for fabricating two-dimensional sandwich-type material-based aerogels with versatile applications.