Reduced graphene oxide-assisted hydrothermal post-treatment of β‑nickel hydroxide nanosheets/nickel foam hybrid electrode for high performance supercapacitors

Nickel hydroxide (Ni(OH)2) is a promising electrode material for supercapacitors due to its high theoretical capacity, low cost, environmental friendliness, and stability in alkaline electrolytes. Herein, we report a novel synthetic approach to enhance the electrochemical performance of Ni(OH)2 through dip-coating reduced graphene oxide(rGO) onto the hydrothermally grown Ni(OH)2 nanosheets and the subsequent hydrothermal post-treatment. The rGO/Ni(OH)2@Ni foam electrode material exhibits a specific capacity of 2437 mC cm−2 at a current density of 1 mA cm−2 and retains 81 % of the initial capacity even after the current density is increased tenfold. The asymmetric supercapacitor utilizing rGO/Ni(OH)2@Ni foam electrode material as the positive electrode maintained 70 % of its initial specific capacity even after 6000 charge/discharge cycles. Notably, we also found that the dip-coated rGO helped to maintain the microstructure of the Ni(OH)2 nanosheets during hydrothermal post-treatment. The present work provides a novel strategy to enhance the electrochemical performance of the electrode materials for supercapacitors which shows great promise in the field of energy storage.