Nanocomposites of honeycomb double-layered MnO2 nanosheets /cobalt doped hollow carbon nanofibers for application in supercapacitor and primary zinc-air battery

A honeycomb double-layered MnO2 nanosheets were successfully deposited on both inner and outer surface of cobalt-doped hollow porous carbon nanofibers (MnO2/Co-HPCNFs) by the hydrothermal method. Benefitting from its distinctive hollow nanostructure of Co-HPCNFs, honeycomb double-layered nanosheets of MnO2, MnO2/Co-HPCNFs nanocomposites exhibit an enhanced electrochemical performance in supercapacitor and zinc-air battery. The as-prepared MnO2/Co-HPCNFs reveals a higher specific capacitance (446 F/g at 0.5 A/g in 1 M Na2SO4 electrolyte). In addition, the MnO2/Co-HPCNFs nanocomposites display preferable oxygen reduction reaction (ORR) catalytic activity (E1/2 = 0.842V) compared to commercial 20 wt% Pt/C catalyst (E1/2 = 0.830V) and long-term stability. Notably, a primary zinc-air battery assembled by the MnO2/Co-HPCNFs as the air cathode is fabricated and outweighs the Pt/C catalyst in regard to long-term stability and power density. The as-prepared MnO2/Co-HPCNFs shows promising prospect as materials in energy storage and conversion.