Preparation of PEDOT/Ti3C2Tx/Co3S2 composite for quasi-solid-state hybrid supercapacitor with enhanced electrochemical performance

Supercapacitors have immense promise in the field of energy storage, and the choice of electrode materials is of utmost importance. In this study, we have developed a ternary composite electrode material consisting of poly (3,4-ethylenedioxythiophene)/ Ti3C2Tx/Co3S2 (PEDOT/Ti3C2Tx/Co3S2) using a solid-state heating method, without the need for an oxidant. Interestingly, we observed that the exclusion of an oxidant such as ferric chloride has proven advantageous in preventing the oxidation of Ti3C2Tx nanosheets. Moreover, the synergistic effect between Co3S2 and Ti3C2Tx nanosheets enhances the structural stability of the composite material during the electrochemical process. The presence of PEDOT on the surface of Ti3C2Tx/Co3S2 acts as a reinforcing agent, effectively preventing the self-stacking of Ti3C2Tx and thereby increasing the specific surface area and conductivity of the resulting composite. Furthermore, the synergistic effects between different phases in the composite material can accelerate the interface charge transfer in the electrochemical redox process. Electrochemical results show that the gravimetric capacitance of the PEDOT/Ti3C2Tx/ Co3S2 is 1135.6 F g-1. The quasi-solid supercapacitor assembled by combining the PEDOT/Ti3C2Tx/Co3S2 with alkaline hydrogel electrolyte (PVA/ KOH) exhibits an energy density of 35.94 Wh kg-1 and a power density of 750.05 W kg-1 at 4 A g-1. After 20,000 cycles, the capacitance retention rate is 110.89%, and the Coulomb efficiency is 95.37%.