文摘
Nanolayered structures present significantly enhanced electrochemical performance by facilitating the surface-dependent electrochemical reaction processes for supercapacitors, which, however, causes capacitance fade upon cycling due to their poor chemical stability. In this work, we report a simple and effective approach to develop a stable, high performance electrode material by integrating 2D transition metal hydroxide and reduced graphene oxide sheets at nanometer scale. Specifically, a hybrid nanolayer of Ni–Co hydroxide @reduced graphene oxide (Ni,Co–OH/rGO) with an average thickness of 1.37 nm is synthesized through an easy one-pot hydrothermal method. Benefiting from the face to face contact model between Ni–Co hydroxide and rGO sheets, such unique structure presents superior specific capacitance and cycling performance as compared to the pure Ni–Co hydroxide nanolayers. An asymmetric supercapacitor based on Ni,Co–OH/rGO and three-dimensional (3D) hierarchical porous carbon is developed, exhibiting a high energy density of 56.1 Wh kg–1 along with remarkable cycling stability (80% retention after 17?000 cycles), which holds great promise for practical applications in energy storage devices.