Coprecipitation Reaction System Synthesis and Lithium-Ion Capacitor Energy Storage Application of the Porous Structural Bimetallic Sulfide CoMoS4 Nanoparticles

Abstract Lithium-ion capacitors (LICs) are noticed as a new-type of energy storage device with both capacitive mechanism and battery mechanism. The LICs own outstanding power density and energy density. In our work, an LIC was constructed by using a simple method to prepare a bimetallic sulfide of CoMoS4 nanoparticles as the anode and a self-made biochar [fructus cannabis’s shells (FCS)] with excellent specific surface area as the cathode. The CoMoS4//FCS LIC demonstrated that the range of energy density is from 10 to 41.9 W h/kg and the range of power density is from 75 to 3000 W/kg in the meantime, and it also demonstrated a remarkable cycling performance with the capacitance retention of 95% after 10 000 cycles of charging–discharging at 1 A/g. The designed CoMoS4//FCS LIC device exhibits a superior electrochemical performance because of the CoMoS4 loose porous structure leading to excellent dynamic performance, which is conducive to the diffusion of electrolyte and lithium ion transport, and good electric double layer performance of biochar with large specific surface area could be achieved. Therefore, this bimetallic sulfide is a promising active material for LICs, which could be applied to electric vehicles in the future.