Synthesis of a MnS/Ni S composite with nanoparticles coated on hexagonal sheet structures as an advanced electrode material for asymmetric supercapacitors.

Herein, a facile hydrothermal method was designed to synthesize a novel structure of micro-flowers decorated with nanoparticles. The micro-flower structure consists of enormous cross-linked flat hexagonal nanosheets with sufficient internal space, providing fluent ionic channels and enduring volume change in the electrochemical storage process. As expected, the MnS/Ni S (NMS) electrode exhibits a relatively high specific capacitance of 1073.81 F g (at 1 A g) and a good cycling stability with 82.14% retention after 2500 cycles (at 10 A g). Furthermore, the assembled asymmetric supercapacitor achieves a high energy density of 46.04 W h kg (at a power density of 850 W kg) and exhibits excellent cycling stability with 89.47% retention after 10 000 cycles. The remarkable electrochemical behavior corroborates that NMS can serve as an advanced electrode material.