Self-Assemble Strategy to Fabricate High Polyaniline Loading Nanocarbon Hydrogels for Flexible All-Solid-State Supercapacitors

Polyaniline and nanocarbon composite hydrogels (PCR) are fabricated by a self-assemble strategy with polyaniline content as high as 66.7%, where multiwall carbon nanotubes (MWCNTs) as reinforcing bars are embedded into the three-dimensional graphene skeletons to enhance the conductivity and mechanical stability. After the incorporation of MWCNTs, the conductivity, porous volume, and specific surface area of the PCR hydrogel increase 32, 53, and 36.8% with respect to the PR hydrogel, respectively. First-principles density functional theory calculations show that the interactions between PANI and graphene/GO are all adsorptive, thereby producing a much more homogeneous and compact structure. Due to this favorable structure, the stress and mechanical degradations of PANI can be alleviated during the repeated charge/discharges. As such, the as-prepared hydrogel-based supercapacitor electrode shows a very high specific capacitance about 917 F g–1 at 1 A g–1 and relatively high rate capability of about 84% from 1 to 20 A g–1. The assembled flexible asymmetric all-solid-state supercapacitor achieves a high energy density of about 31.32 W h kg–1 at the power density (364.93 W kg–1). These results demonstrate that polyaniline and nanocarbon composite hydrogels have great potential to become an advanced power device for wearable electronics.