Fabrication and supercapacitor behavior of phosphomolybdic acid/polyaniline/titanium nitride core–shell nanowire array
Phosphomolybdic acid (PMo12) with reversible electron shuttling is a potential electrode material. Possessing good solubility limits its applications in energy storage. A novel and efficient phosphomolybdic acid/polyaniline/titanium nitride core–shell nanowire array (PMo12/PANI/TiN NWA) was synthesized as a supercapacitor electrode. FT-IR and Raman spectra showed that PMo12 was well incorporated into PANI and the structures of PANI and PMo12 were completely retained. PMo12/PANI/TiN NWA displayed core–shell nanowire array morphology with narrow diameters and oriented perpendicular to the substrate, benefiting ion diffusion and electron transportation. The PMo12/PANI/TiN NWA electrode exhibited a higher specific capacitance of 469 F g−1 at 1 A g−1 compared with PANI/TiN NWA electrode. PMo12/PANI/TiN supercapacitor could achieve a specific capacitance of 69 F g−1 and an energy density of 21.6 W h kg−1 at a current density of 0.5 A g−1 and an output voltage of 1.5 V. The effects of PMo12 incorporated in PANI and the immobilization mechanism of PMo12 are proposed and discussed.