Two-dimensional nanosheets constituted trimetal Ni-Co-Mn sulfide nanoflower-like structure for high-performance hybrid supercapacitors

Abstract

Trimetal NiCoMn-based sulfides with two-dimensional (2D) nanosheets constituted flower-like structures have been synthesized using an anion exchange approach, which exhibit excellent performance as electroactive battery materials for hybrid supercapacitors. These NiCoMn-based sulfides were transformed from layered hydroxides while well maintaining 2D nanosheets constituted flower-like structure. The amounts of Mn constitution have been tuned to control performance of sulfides. It is found that Mn doping causes formation of pure phase sulfide while maintaining same flower-like structure. Mn-doping can enhance specific capacity and cycling stability of sulfides, and resulting sulfides maintain a low charge transfer resistance. Mn-doped sulfides display a maximum specific capacity of 657.7C g−1 at 1 A g−1, and a specific capacity of 339.5C g−1 has been achieved when the specific current increases by 50 times to 50 A g−1. More significantly, the NiCoMn-based sulfide has been used to assemble hybrid supercapacitors with reduced graphene oxide, which achieves a maximum specific energy of 36.3 Wh kg−1 combined with long-term cycling stability.