Designed MnS/Co9S8 micro-flowers composites with serrate edges as high-performance electrodes for asymmetric supercapacitor.

The three-dimensional (3D) MnS/Co9S8 (MCS) micro-flowers composites with serrate edges on Ni foam were successfully prepared by a facile hydrothermal method. The time-dependent experiments showed that the structure was assembled by two-dimensional (2D) nanobelts. The serrate edges structures of MCS can enrich electroactive sites and enhance the specific capacity (1070 C/g at 1 A/g). In addition, MCS exhibited good cycling stability of 86% after 1000 cycles. Further, an asymmetric supercapacitor device was constructed by using MCS as the positive electrode and activated carbon (AC) as the negative electrode, which exhibited high energy density of 34.1 Wh/kg at power density of 400 W/kg with good cycling stability. The superior electrochemical performances demonstrated that the micro-flowers composites with serrate edges could offer a new opportunity in developing energy storage devices.