Probing the electrical properties and energy storage performance of electrospun ZnMn2O4 nanofibers

Abstract

Spinel structure ZnMn2O4 (ZMO) nanofibers with specific surface area of 30 m2 g−1 are fabricated by simplistic, adaptable and cost effective electrospinning process. ZMO nanofibers are characterized by various characterization techniques, namely TGA, XRD, FTIR, BET surface area analyzer, FESEM and TEM techniques. Dielectric studies of ZMO nanofibers are performed in the frequency range of 20 Hz to 1 MHz at room temperature, which follows the Maxwell-Wagner model. Electrochemical performance of ZMO nanofibers has been probed via cyclic voltammetry (CV), galvanostatic charging-discharging (GCD) and electrochemical impedance spectroscopy (EIS) for supercapacitor applications. Spinel ZMO nanofiber is found to be a prospective electrode material due to the presence of structural voids/gaps in it, which contribute effectively to the energy storage performance of the material. Furthermore, the nanofibric network of interconnected nanoparticles with high surface area is expected to facilitate the foreign ions transportation into electrode material which improves the energy storage performance. The observed specific capacitance of ZMO is found to be 240 (±5) F g−1 at current density of 1 A g−1. The specific energy density and the power density of ZMO are come out to be 33.3 W h kg−1 and 500 W kg−1, respectively, at current density of 1 A g−1. Impedance study demonstrates the low resistance and short diffusion path for electrolytic ions within the material. These remarkable results demonstrate that ZMO can be utilized in the designing of practical high performance supercapacitor devices.