Controllable synthesis of hollow spherical nickel chalcogenide (NiS(2) and NiSe(2)) decorated with graphene for efficient supercapacitor electrodes

New carbon-loaded nickel chalcogenide electrode materials (NiS(2)/GO and NiSe(2)/rGO) have been synthesized through an easy-to-operate process: NiSe(2) was obtained based on NiS(2) hollow spheres, and was successfully synthesized with l-cysteine assistance under the hydrothermal method at 120 °C. GO of different mass fraction was added together with l-cysteine. The electrochemical performance of NiS(2)/GO and NiSe(2)/rGO has been greatly improved because the formation of a carbon-loaded layer effectively increased the specific surface area and reduced the charge transport resistance. Compared with pure NiS(2) and NiSe(2), NiS(2)/GO and NiSe(2)/rGO presented much better specific capacitance (1020 F g(−1) and 722 F g(−1) respectively at a current density of 1 A g(−1)) and more superior rate capability (when the current density was raised to 5 A g(−1) the specific capacitance remained at 569 F g(−1) and 302 F g(−1)). This work highlights the advantages of nickel compounds through a very simple experimental method, and contributes to providing a good reference for preparation of superior supercapacitor materials with high performance.