Homogeneous MnO2@TiO2 core-shell nanostructure for high performance supercapacitor and Li-ion battery applications

Abstract

In this work, MnO2 layered TiO2 core-shell nanostructure is prepared by a two-step method. The prepared homogeneous MnO2 layered TiO2 core-shell architecture characterized by various physiochemical techniques. The crystalline nature and other structural details of the synthesized core-shell architecture obtained from powder X-ray diffraction (XRD) technique. The formation of core-shell architecture confirmed by field emission electron microscopy (FE-SEM) technique and the elemental analysis carried out using energy-dispersive X-ray spectroscopy (EDS) analysis. The electrochemical behavior of the prepared MnO2 layered TiO2 core-shell architecture studied using cyclic voltammetry (CV), charge-discharge, and electrochemical impedance techniques in 1 M Li2SO4 aqueous electrolyte. The prepared MnO2 layered TiO2 core-shell architecture shows high specific capacitance and energy density value of 564 F g−1 and 38.39 Wh kg−1, respectively, at the applied current density of 2 A g−1. Further, the resistive and capacitive nature of the synthesized electrode material studied from Nyquist and bode diagrams within the frequency range of from 10 mHz to 100 kHz. Finally, a MnO2 layered TiO2 nanorods/activated carbon asymmetric supercapacitor device fabricated and its lithium-ion storage capacity evaluated at different applied current densities. With these outstanding electrochemical performances, prepared MnO2@TiO2 core-shell nanostructure holds good potential to develop high-performance electrochemical energy storage devices.