Electrospun nanofiber of hybrid manganese oxides for supercapacitor: Relevance to mixed inorganic interfaces

•3-Dimensional MnOx nanofiber was formed by electrospinning.•Upon calcination at different temperatures, MnOx NFs became variable composition of Mn3O4 to Mn2O3.•This study examined the supercapacitor performance depending on the phases of MnOx.•We found that mixed phase exhibited a higher capacity than that of respective single phase.•The high specific capacitance was attributed to 3D structure and the reduced interfacial resistance.

We prepare electrospun nanofibers (NFs) from a poly(N-vinylpyrrolidone)/manganese (II) acetate composite by electrospinning for application in supercapacitors. As-spun hybrid NFs are calcined at different temperatures to remove the polymer matrix, resulting in inorganic MnOx NFs of variable compositional ratios of Mn3O4 to Mn2O3. Interestingly, the sample of MnOx NFs that is calcined at 500 °C exhibits the highest electrochemical performance, reaching a high specific capacitance of 360.7 F g−1 at a current density of 1 A g−1. This remarkable performance is attributed to the unique three-dimensional morphology and the reduced interfacial resistance of the mixed-phase MnOx NFs within the matrix electrode and the electrolyte.