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

Abstract Nickel cobalt sulfide (NiCo 2 S 4 ) nanosheets were successfully grown on porous graphitic carbon nitride (g-C 3 N 4 ) nanosheets (NiCo 2 S 4 NSs/P-g-C 3 N 4 ), which was employed as supercapacitor electrode materials. The NiCo 2 S 4 NSs/P-g-C 3 N 4 electrode shows specific capacity as high as 506 C g −1 at a current density of 1 A g −1 , outstanding rate capability and cycling stability (almost no attenuation after 1500 cycles at 3 A g −1 ), which can be attributed to the unique ‘sheets on sheets’ architectures providing short ion diffusion pathways, and good ion permeability. NiCo 2 S 4 NSs/P-g-C 3 N 4 was combined with activated carbon (AC) to construct NiCo 2 S 4 NSs/P-g-C 3 N 4 //AC asymmetric supercapacitor (ASC), which offers a specific energy of 16.7 W h kg −1 at a specific power of 200 W kg −1 , and high cycling performance (about 99% retention after 5000 continuous cycles). An ASC device could power a mini-fan for about 60 s, demonstrating that NiCo 2 S 4 NSs/P-g-C 3 N 4 is a potential electrode material for energy storage.