Mesoporous MnNiCoO4@MnO2 core-shell nanowire/nanosheet arrays on flexible carbon cloth for high-performance supercapacitors

Abstract

For the first time, a novel three-dimensional (3D) hierarchical mesoporous MnNiCoO4@MnO2 core-shell nanowire/nanosheet arrays hybrid composite with robust adhesion on a carbon cloth (CC) as an integrated self-supported supercapacitor electrode was synthesized via a facile two-step hydrothermal method and a subsequent low temperature annealing process. The synthesized materials were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and electrochemical techniques. The results show that this unique nanostructure merits superiorities such as large surface area, more accessible active sites, better infiltration/diffusion, high conductivity and high electrochemical/mechanical stability. The MnNiCoO4@MnO2 core-shell nanoarrays can achieve a relatively high specific capacitance of 1931Fg−1 at a current density of 0.8Ag−1, a good capacitance retention of 91.2% at a high current density of 6Ag−1 after 6000 cycles, a low equivalent series resistance (ESR) of 0.53Ω, an energy density of 67.1Whkg−1 at a power density of 200Wkg−1 in 6molL−1 KOH electrolyte. The remarkable electrochemical behaviors indicate that the carbon cloth supported hierarchical mesoporous MnNiCoO4@MnO2 core-shell nanowire/nanosheet array electrodes are highly promising for applications like advanced supercapacitor electrodes.