Hierarchical MnCo2O4@CoMoO4 core-shell nanowire arrays supported on Ni foam for supercapacitor

Abstract

Hierarchical MnCo2O4@CoMoO4 core-shell nanowire arrays (NAs) with mesoporous and large surface area are successfully synthesized on Ni foam via a facile, two-step hydrothermal method. In the hierarchical structure, the MnCo2O4 NAs act as a backbone for directly electron conductive pathway, and the ultrathin CoMoO4 nanosheets (NSs) serve as the shell, which uniformly loading onto the MnCo2O4 NAs, significantly enhancing the surface area of the electrode, providing more active sites for Faradaic redox reactions. In addition, the mesoporous and NAs structures are very beneficial for the penetration of electrolyte, leading to an efficient ion transfer rates. Due to the synergistic effects contributed from both the porous MnCo2O4 NAs core and the CoMoO4 shell, the hierarchical electrode exhibits high specific capacitance (2115.38 F g-1 at 1.1 A g−1), excellent rate capability and superior cycling stability (maintaining 119% even after 5000 cycles at a current density of 19 A g−1). Additionally, an asymmetric device is fabricated with MnCo2O4@CoMoO4 core-shell NAs as the positive electrode and active carbon (AC) as the negative electrode. Impressively, the MnCo2O4@CoMoO4//AC asymmetric device shows a high energy density of 37.5 Wh kg−1 at a power density of 527.8 W kg−1, indicating the great promise of practical applications.