Holey graphene/polypyrrole nanoparticle hybrid aerogels with three-dimensional hierarchical porous structure for high performance supercapacitor

Holey graphene/polypyrrole hybrid aerogels (HGPAs) with three-dimensional (3D) hierarchical structure have been fabricated by freeze-drying holey graphene/polypyrrole hydrogels, which are assembled by using holey graphene (HG) nanosheets and polypyrrole (PPy) nanoparticles as assembling primitives. The as-prepared HGPAs materials show an interconnected and stable 3D porous network, and PPy nanoparticles uniformly embedded in the aerogel prevent the restacking of holey graphene (HG) nanosheets. The unique hierarchical porous structure and synergistic effect between PPy nanoparticles and HG nanosheets make HGPA hybrid aerogel electrode with a mass ratio of PPy/HGO = 0.75 exhibits high specific capacitance (418 F g−1) at a current density of 0.5 A g−1, extremely outstanding rate capability (80%) at various current densities from 0.5 to 20 A g−1 and good cycling performance (74%) after 2000 cycles in 1.0 M KOH aqueous electrolyte. Moreover, the effect of the PPy nanoparticle sizes in HGPAs on their electrochemical properties is also investigated, and PPy nanoparticles with relatively larger sizes are favorable of the good capacitive performance for the obtained electrodes. The facile and efficient preparation method for HGPAs electrodes may be developed for preparing other holey graphene-based hybrid aerogels with structure-controllable nanostructures. A facile preparation method is developed for holey graphene/polypyrrole hybrid aerogels with 3D hierarchical porous structure, which is beneficial for shortening the diffusion length of electrolyte ions during the charge-discharge process and providing multiplexed conduction pathways with large specific surface area to ensure rapid charge transfer and transport. The obtained hybrid aerogel with a mass ratio of PPy/HGO = 0.75 exhibits high specific capacitance, extremely outstanding rate capability and good cycling performance. [Display omitted] •A facile preparation method for HGPAs by using HG and PPy as assembling primitives.•The HGPAs show hierarchical porous network with PPy uniformly embedded in aerogel.•The superior supercapacitor performance of HGPAs benefits from the unique structure.•The effect of PPy nanoparticle sizes on electrochemical properties is investigated.