In–situ synthesis of MnO dispersed carbon nanofibers as binder-free electrodes for high-performance supercapacitors.

[Display omitted] • In-situ incorporation of MnO in the CNF matrix using unique two-step carbonization. • MnO dispersed CNFs show high specific capacitance of 246F g−1 at 0.5 A g−1. • High power density of 5000 W kg−1 (8.7 W h kg−1) was achieved with 97.5 % capacitance retention after 10,000 cycles. Manganese oxides have attracted great interest as promising pseudocapacitive materials due to its low cost, variable oxidation states, and high theoretical capacitance. In this work, we report the in-situ synthesis of MnO-dispersed carbon nanofibers (CNFs) using electrospinning and a unique two-step carbonization technique. While the single-step carbonization resulted in mixed Mn x O y forms, however, by employing a suitable and optimized two-step carbonization, we were able to obtain CNFs assimilated with MnO nanoparticles (MnO-CNFs). The synthesized MnO-CNF electrodes achieved a high specific capacitance of 246 F g−1 at 0.5 A g−1 in a three-electrode system. A symmetric supercapacitor device assembled with these electrodes exhibited remarkable electrochemical performance with a maximum power density of 5000 W kg−1, maximum energy density of 14 W h kg−1, and an excellent cycling stability (97.5% retention after 10,000 cycles). The exceptional electrochemical performance of MnO-CNFs makes them promising electrode materials for practical energy storage applications. [ABSTRACT FROM AUTHOR]