Nickel sulfide and cobalt sulfide nanoparticles deposited on ultrathin carbon two-dimensional nanosheets for hybrid supercapacitors

The construction of battery-type cathodes with glorious electrochemical features is of great significance for hybrid supercapacitors. Herein, an effective one-step calcination strategy is demonstrated for the fabrication of nickel sulfide and cobalt sulfide nanoparticles deposited on ultrathin carbon two-dimensional nanosheets (Ni3S2/Co9S8/C) by employing sodium sulfate (Na2SO4) as the sulfur source and template. Benefiting from the remarkable combination of multiple functional components and the ultrathin two-dimensional architecture, the constructed Ni3S2/Co9S8/C cathode features with a commendable capacity of 1160 C g−1 (2320 F g−1) at 1 A g−1 and a decent cyclic capability at 10 A g−1 (91.3% after 10,000 cycles). In addition, the manufactured hybrid supercapacitor with Ni3S2/Co9S8/C cathode and p-phenylenediamine modified graphene (PMG) anode achieves a maximum energy density of 69.6 Wh kg−1 at 970.5 W kg−1 and an appropriate cyclic capability of 82.6% after 20,000 cycles. These fascinating results reveal the great potential of Ni3S2/Co9S8/C ultrathin nanosheets for practical application.