Synthesis and electrochemical performance of MnO ₂/CNTs-embedded carbon nanofibers nanocomposites for supercapacitors

MnO ₂/carbon nanotubes (CNTs)-embedded carbon nanofibers (CNFs) nanocomposites (MnO ₂/CNTs-CNFs) have been prepared using electrospinning and in situ redox deposition technique. The as-prepared nanocomposites were directly employed as freestanding electrodes to evaluate the electrochemical properties. Results showed that the nanoscopic MnO ₂ deposits were incorporated uniformly into the CNTs-embedded CNFs network structure, which hold a great promise for high-performance supercapacitor applications. Compared to the pure CNFs substrate, the improved electric conductivity of CNTs-embedded CNFs substrate enabled a better utilization of MnO ₂ coating, thus resulting in higher specific capacitance (374 F/g) and better rate capability (53.4%). Excellent capacitance retention of 94% of the initial capacitance after 1000 cycles was achieved on the freestanding MnO ₂/CNTs-CNFs nanocomposites electrode. The specific capacitance was found to increase significantly with the increase in the electrolyte temperature, which offered an insight into the practical supercapacitor applications.