Design and synthesis of MoSe 2 /C composites for the high performance supercapacitor electrode material

Abstract Molybdenum diselenide (MoSe₂), a transition metal diselenide, exhibits substantial pseudocapacitive behavior but suffers from intrinsically low electrical conductivity. This limitation impedes rapid electron transport within electrodes, particularly during high-rate charge/discharge cycles. To address this challenge, we engineered MoSe₂/C composites by integrating conductive carbon matrices that serve as efficient "electron highways", significantly enhancing overall electrical conductivity. The composites were synthesized via a one-step hydrothermal method using glucose as the carbon source directly introduced into the MoSe₂ precursor system. Structural and morphological characterizations (SEM, XRD, XPS) confirmed the successful formation of lamellar MoSe₂/C nanocomposites. Electrochemical evaluation revealed the special performance of the supercapacitor. At 1 A g⁻ ¹, the specific capacitance of the optimized composite electrode was 235.85 F g⁻ ¹, which was 69.4% higher than that of the original MoSe₂. After 500 cycles, it maintained 96.8% capacity retention with a 33.1% improvement in cycling stability. Systematic investigation of carbon doping ratios (four experimental groups) demonstrated a volcano-type relationship between electrochemical performance and carbon content, identifying a 1:10 MoSe₂:C molar ratio as optimal. The carbon framework facilitates rapid Faradaic reactions at MoSe₂ active sites, thereby substantially boosting both rate capability and long-term cycling stability.