Asymmetric supercapacitors based on SnNiCoS ternary metal sulfide electrodes

Abstract

While metal sulfides have extensively investigated as electrode materials for supercapacitors, the further optimization of their material system is still necessary to achieve satisfied performance. In this work, we reported the synthesis of ternary metal sulfide SnNiCoS and its application as electrode material of asymmetric supercapacitors, in which active carbon is used as the other electrode. For control experiments, asymmetric supercapacitors based on single metal sulfide CoS and binary metal sulfide NiCoS are also fabricated and investigated. The results show that the nanospherical SnNiCoS achieves the best performance. Ternary sulphide materials offer more redox than corresponding single-metal sulphides due to the synergy among various transition metal elements. The specific capacitance is 18.6 F cm−2 at current density of 5 mA·cm−2. An energy density of 937.2 μWh cm−2 is achieved at a power density of 4000 μW·cm−2. After 8000 cycles, the capacity retention rate is 82.9%. Present work indicates that SnNiCoS ternary metal sulfide could be a promising composite for high performance supercapacitors.