High-performance asymmetric full-cell supercapacitors based on CoNi2S4 nanoparticles and activated carbon

Abstract

CoNi2S4 nanoparticles with a maximum specific capacitance of 1636.2 F g−1 are synthesized by a facile solvothermal method. In order to explore the real applying value, asymmetric full-cell supercapacitors are successfully assembled by employing CoNi2S4 nanoparticles as positive electrode and activated carbon as negative electrode. As a contrast, symmetric full-cell supercapacitors are also assembled by employing the CoNi2S4 nanoparticles as positive/negative electrode. Electrochemical properties of these assembled asymmetric and symmetric full-cell supercapacitors are investigated in 3.0 mol L−1 KOH electrolyte. Results show that the present asymmetric full-cell supercapacitors exhibit excellent electrochemical capacitance performance within the potential range of 0–1.6 V, i.e., a maximum specific capacitance of 163.9 F g−1, high energy density of 36.7 Wh kg−1 at a power density of 7630 W kg−1, and excellent cycling stability. Furthermore, two asymmetric full-cell supercapacitors linked in series cannot only light a red light-emitting diode, but also drive a rotating motor. Hence, one can see that the asymmetric full-cell supercapacitors based on CoNi2S4 nanoparticles and activated carbon have the promising potential application in the field of energy storage.