CoNi2S4‐Graphene‐2D‐MoSe2 as an Advanced Electrode Material for Supercapacitors

3D CoNi 2 S 4 ‐graphene‐2D‐MoSe 2 (CoNi 2 S 4 ‐G‐MoSe 2 ) nanocomposite is designed and prepared using a facile ultrasonication and hydrothermal method for supercapacitor (SC) applications. Because of the novel nanocomposite structures and resultant maximized synergistic effect among ultrathin MoSe 2 nanosheets, highly conductive graphene and CoNi 2 S 4 nanoparticles, the electrode exhibits rapid electron and ion transport rate and large electroactive surface area, resulting in its amazing electrochemical properties. The CoNi 2 S 4 ‐G‐MoSe 2 electrode demonstrates a maximum specific capacitance of 1141 F g −1 , with capacitance retention of ≈108% after 2000 cycles at a high charge–discharge current density of 20 A g −1 . As to its symmetric device, 109 F g −1 at a scan rate of 5 mV s −1 is exhibited. This pioneering work should be helpful in enhancing the capacitive performance of SC materials by designing nanostructures with efficient synergetic effects.