Facile synthesis of polyaniline nanotubes using reactive oxide templates for high energy density pseudocapacitors

A remarkable energy density of 84 W h kg(cell)−1 and a power density of 182 kW kg(cell)−1 have been achieved for full-cell pseudocapacitors using conducting polymer nanotubes (polyaniline) as electrode materials and ionic liquid as electrolytes. The polyaniline nanotubes were synthesized by a one-step in situ chemical polymerization process utilizing MnO2 nanotubes as sacrificial templates. The polyaniline-nanotube pseudocapacitors exhibit much better electrochemical performance than the polyaniline-nanofiber pseudocapacitors in both acidic aqueous and ionic liquid electrolytes. Importantly, the incorporation of ionic liquid with polyaniline-nanotubes has drastically improved the energy storage capacity of the PAni-nanotube pseudocapacitors by a factor of ∼5 times compared to that of the PAni-nanotube pseudocapacitors in the acidic aqueous electrolyte. Furthermore, even after 10 000 cycles, the PAni-nanotube pseudocapacitors in the ionic liquid electrolyte maintain sufficient high energy density and can light LEDs for several minutes, with only 30 s quick charge.