Preparation and characterization of three-dimensional Mn–Mo–S composites on rGO/Ni foam for battery-supercapacitor electrode with high-performance

Abstract Rational design of structures and higher electrical conductivity are two crucial routes to improving the electrochemical performances of battery-supercapacitors (SCs). In this paper, we have successfully synthesized the three-dimensional (3D) manganese-molybdenum-sulfide (Mn–Mo–S) composites with the microsphere morphology on the reduced graphene oxide/Ni foam (rGO/NF) substrate through a facile two-step hydrothermal method. The effects of sulfurization time on the morphologies and electrochemical performances were clearly identified. Benefiting from the unique microsphere structure and their synergistic effects between the composites, the 3D composite battery-type electrode has a fast ion and electron transfer, the abundant active sites and superior conductivity. As a result, the composite employed for battery-supercapacitors delivers the excellent specific capacity of 1637.1 C g−1 at 1 A g−1 when the sulfurization time is 3 h (MMS/rGO/NF-3h), and as well as the advantageous 96.5% of the original capacity through 8000 cycles. In addition, a battery-supercapacitor hybrid (BSH) device based on the MMS/rGO/NF-3h (positive) and active carbon (negative) shows a remarkable energy density of 59.8 W h kg−1 at power density of 402.4 W kg−1. With such outstanding electrochemical performances, the MMS/rGO/NF-3h//AC BSH device holds great potential in developing high-energy storage applications.