Convenient synthesis of Ni-Mn-S@rGO composite with enhanced performance for advanced energy storage applications

Abstract

As a promising energy storage device, the performance of supercapacitors is greatly influenced by the electrode material. Here, we designed a simple Ni-Mn-S@rGO composite material. The rGO with a two-dimensional layered structure serves as the basis for the in-situ growth of Ni-Mn-S microspheres, which effectively reduces the aggregation of sulfides, provides a rapid electron migration channel, and effectively improves the electrochemical performance of the material. In addition, the synergy between different metal ions will also affect the properties of the materials. Therefore, the materials are optimized by controlling the proportion of different components in the raw materials. The results show that the Ni-Mn-S@rGO-2 with proper composition has a superior specific capacitance of 2042.22F g−1 (at 1A g−1) and a retention rate of 77.78% after 5000 cycles. An all-solid-state asymmetric supercapacitor was fabricated using Ni-Mn-S@rGO-2 and active carbon as electrode materials. The device achieved a high energy density of 77.95 Wh kg−1 at a power density of 750W kg−1. Furthermore, the device retains 81.97% specific capacitance after 10000 charge-discharge cycles, which indicates that the device has satisfactory cycle stability. These results prove that Ni-Mn-S@rGO composites have potential applications in the field of supercapacitors.