Effect of Ti3C2Tx–PEDOT:PSS modified-separators on the electrochemical performance of Li–S batteries

Abstract

Lithium–sulfur (Li–S) batteries have attracted much attention due to their high theoretical energy density, environmental friendliness, and low cost. However, the practical application of Li–S batteries is impeded by a severe shuttle effect. Using polar and conductive materials to prepare a modified separator as the second collector is an effective strategy to solve the shuttle effect. Herein, a Ti₃C₂T_x–PEDOT:PSS hybrid for modifying PP separators is successfully fabricated. In this hybrid, PEDOT:PSS can effectively prevent Ti₃C₂T_x nanosheets from restacking and enhance the electrical conductivity of Li–S batteries, thereby promoting fast Li⁺/electron transport and improving the sulfur utilization. Meanwhile, the introduction of Ti₃C₂T_x–PEDOT:PSS makes Ti₃C₂T_x nanosheets effectively anchor polysulfide, thus inhibiting the shuttle effect. As a result, Li–S cells with Ti₃C₂T_x–PEDOT:PSS modified-separators exhibit superior performances, including a high discharge capacity of 1241.4 mA h g⁻¹ at 0.2C, a long cycling stability, and a low decay rate of 0.030% per cycle at 0.5C for 1000 cycles.