Conductive Polymer-Coated VS4 Submicrospheres As Advanced Electrode Materials in Lithium-Ion Batteries

VS4 as an electrode material in lithium-ion batteries holds intriguing features like high content of sulfur and one-dimensional structure, inspiring the exploration in this field. Herein, VS4 submicrospheres have been synthesized via a simple solvothermal reaction. However, they quickly degrade upon cycling as an anode material in lithium-ion batteries. So, three conductive polymers, polythiophene (PEDOT), poly-pyrrole (PPY), and polyaniline (PANT), are coated on the surface to improve the electron conductivity, suppress the diffusion of polysulfides, and modify the interface between electrode/electrolyte. PANT is the best in the polymers. It improves the Coulombic efficiency to 86% for the first cycle and keeps the specific capacity at 755 mAh g(-1) after 50 cycles, higher than the cases of naked VS4 (100 mAh g(-1)), VS4@PEDOT (318 mAh g(-1)), and VS4@PPY (448 mAh g(-1)). The good performances could be attributed to the improved charge-transfer kinetics and the strong interaction between PANT and VS4 supported by theoretical simulation. The discharge voltage similar to 2.0 V makes them promising cathode materials.