3D core/shell hierarchies of MnOOH ultrathin nanosheets grown on NiO nanosheet arrays for high-performance supercapacitors

As the most promising electrode material for supercapacitors, core/shell hybrid material will enhance the electrochemical performance comparing with single component constituent, thus has recently drawn our research. Herein, we have designed and synthesized 3D hierarchical hetero-structures of dense MnOOH ultrathin nanosheets grown on porous hierarchical NiO nanosheet arrays by facial and rational process. In this configuration, porous hierarchical NiO nanosheet arrays serve as fast ion and electron transport model and dense MnOOH ultrathin nanosheets enhance the contact surface area and assist ions penetrate into the core region to realize the release of potential electrochemical properties of NiO nanosheet arrays, and thus these heterostructures provide intense needed critical function for efficient use of metal oxide and hydroxide in energy storage. As an electrode, the as-fabricated 3D NiO@MnOOH core/shell nanosheet hierarchies exhibited favorable electrochemical performances, i.e., high specific capacitance of 1625.3 F/g at a current density of 4 A/g with a remarkable rate capability and excellent energy density (80.0 Wh/kg), as well as good cycling stability (105.7% of the initial capacitance after 5000 cycles). It suggests that they should have a promising potential for the next generation energy conversion-storage devices. (C) 2014 Elsevier Ltd. All rights reserved.