Synthesis of Hierarchical Porous Ni(1.5)Co(1.5)S(4)/g-C(3)N(4) Composite for Supercapacitor with Excellent Cycle Stability

In this work, the hierarchical porous Ni(1.5)Co(1.5)S(4)/g-C(3)N(4) composite was prepared by growing Ni(1.5)Co(1.5)S(4) nanoparticles on graphitic carbon nitride (g-C(3)N(4)) nanosheets via a hydrothermal route. Due to the self-assembly of larger size g-C(3)N(4) nanosheets as a skeleton, the prepared nanocomposite possesses a unique hierarchical porous structure that can provide short ions diffusion and fast electron transport. As a result, the Ni(1.5)Co(1.5)S(4)/g-C(3)N(4) composite exhibits a high specific capacitance of 1827 F g(−1) at a current density of 1 A g(−1), which is 1.53 times that of pure Ni(1.5)Co(1.5)S(4) (1191 F g(−1)). In particular, the Ni(1.5)Co(1.5)S(4)/g-C(3)N(4)//activated carbon (AC) asymmetric supercapacitor delivers a high energy density of 49.0 Wh kg(−1) at a power density of 799.0 W kg(−1). Moreover, the assembled device shows outstanding cycle stability with 95.5% capacitance retention after 8000 cycles at a high current density of 10 A g(−1). The attractive performance indicates that the easily synthesized and low-cost Ni(1.5)Co(1.5)S(4)/g-C(3)N(4) composite would be a promising electrode material for supercapacitor application.