Ultrasmall SnO2 nanoparticle-intercalated graphene@polyaniline composites as an active electrode material for supercapacitors in different electrolytes

• RGO/SnO2/PANI composite was prepared via a two-step method in ionic liquid and water.
• Ultrasmall SnO2 nanoparticles were intercalated with graphene layers and PANI.
• The composite modified electrodes exhibited a high rate capacity, such as 1012 F g−1 at 4 A g−1.
• This is a novel route for production of other graphene/metal oxide/polymer composites.

A ternary composite of graphene, SnO2 nanoparticles and polyaniline (PANI) was prepared by a two-step method using an ionic liquid and water as the solvents. First, reduced graphene oxide/SnO2 (RGO/SnO2) nanocomposites were synthesized within 10 min using a microwave-assisted method in an ionic liquid without a reducing reagent. Second, the resulting RGO/SnO2 hybrids were coated with polyaniline (PANI) by the in situ polymerization of aniline in an aqueous medium. Transmission electron microscopy and scanning electron microscopy revealed ultrasmall SnO2 nanoparticles, ca. 5 nm in size, intercalated with graphene layers and polyaniline (PANI). The composite modified electrodes exhibited a high rate capacity, such as 1012 F g−1 of Cs in 1 M Na2SO4 at 4 A g−1. Furthermore, the proposed strategy provides a novel method for the fabrication of other ternary graphene-based composites with metal oxide and conducting polymers as electrode materials for supercapacitors.