Nickel cobalt sulfide nanosheets uniformly anchored on porous graphitic carbon nitride for supercapacitors with high cycling performance

Abstract

Nickel cobalt sulfide (NiCo2S4) nanosheets were successfully grown on porous graphitic carbon nitride (g-C3N4) nanosheets (NiCo2S4 NSs/P-g-C3N4), which was employed as supercapacitor electrode materials. The NiCo2S4 NSs/P-g-C3N4 electrode shows specific capacity as high as 506Cg−1 at a current density of 1Ag−1, outstanding rate capability and cycling stability (almost no attenuation after 1500 cycles at 3Ag−1), which can be attributed to the unique ‘sheets on sheets’ architectures providing short ion diffusion pathways, and good ion permeability. NiCo2S4 NSs/P-g-C3N4 was combined with activated carbon (AC) to construct NiCo2S4 NSs/P-g-C3N4//AC asymmetric supercapacitor (ASC), which offers a specific energy of 16.7Whkg−1 at a specific power of 200Wkg−1, and high cycling performance (about 99% retention after 5000 continuous cycles). An ASC device could power a mini-fan for about 60s, demonstrating that NiCo2S4 NSs/P-g-C3N4 is a potential electrode material for energy storage.