Direct growth of Ni–Mn–O nanosheets on flexible electrospun carbon nanofibers for high performance supercapacitor applications

Currently, the search for the fabrication of inexpensive and efficient binder-free electrodes for high performance supercapacitor applications is still a great challenge. In this work, different nanostructures of Ni–Mn oxide (Ni–Mn–O) are directly grown on the surface of flexible electrospun carbon nanofibers (ECNFs) and further used as binder-free electrodes for supercapacitors. Among three typical nanostructures, Ni–Mn–O nanosheets on ECNFs show superior electrochemical properties with a good specific capacitance (368.6 F g−1) and excellent rate properties (88.6% retention at 20 times initial current density) in a three-electrode system. Furthermore, an aqueous symmetry cell and a solid-state symmetry supercapacitor are assembled using two pieces of flexible ECNFs@Ni–Mn–O nanosheets. The maximum energy density and power density based on the solid-state supercapacitor are up to 20.4 W h kg−1 and 5.2 kW kg−1, respectively, indicating that the flexible ECNFs@Ni–Mn–O nanosheets present a fairly promising future for practical applications in the field of energy storage.