High-performance asymmetric supercapacitor based on vanadium dioxide and carbonized iron-polyaniline electrodes

Vanadium dioxide (VO₂) monoclinic nanosheets were synthesized by a solvothermal method and carbonized iron-polyaniline (C-FP) nanograins were prepared by pyrolysis of iron-polyaniline (PANI) mixture under nitrogen ambient. An asymmetric device (VO₂//C-FP) was evaluated with VO₂ and C-FP as positive and negative material electrodes in aqueous 6 M KOH electrolyte respectively. The asymmetric supercapacitor (VO₂//C-FP) exhibited a 47 mA h g^-1 specific capacity and a specific energy of 30 W h kg^-1 with an associated specific power of 713 W kg^-1 at a gravimetric current of 1 A g^-1 in a potential window of 1.6 V. It also displayed an 89% energy efficiency after 10000 galvanostatic charge-discharge cycles with a large improvement after ageing test at a gravimetric current of 10 A g^-1.