Scalable Fabrication of Supercapacitors by Nozzle-Free Electrospinning

Nozzle-free electrospinning was investigated as a facile technique for producing nanoscale materials for supercapacitors. MnO 2 nanofibers and their composites with multiwalled carbon nanotubes (MWCNTs) were synthesized in a single step, using polyvinylpyrrolidone (PVP) and Mn(CH 3 COO) 2 ·4H 2 O as starting materials, followed up by heat treatment in ambient air. Nanofibers of relatively uniform diameter were produced at high rates. The nanofibers exhibited good electrical contact between MnO 2 and MWCNT without degradation, which was attributed to the improved stability of MWCNTs in PVP solutions. Electrochemical testing of the composites demonstrated a high capacitance of 1.43 F cm –2 at a scan rate of 100 mV s –1 in the three-electrode tests. Electrodes and devices produced by nozzle-free electrospinning are promising for practical energy storage applications.