Effect of Ti3C2T: X-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 Ti3C2Tx-PEDOT:PSS hybrid for modifying PP separators is successfully fabricated. In this hybrid, PEDOT:PSS can effectively prevent Ti3C2Tx 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 Ti3C2Tx-PEDOT:PSS makes Ti3C2Tx nanosheets effectively anchor polysulfide, thus inhibiting the shuttle effect. As a result, Li-S cells with Ti3C2Tx-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.