Efficient Catalytic Conversion of Polysulfides in Multifunctional FeP/Carbon Cloth Interlayer for High Capacity and Stability of Lithium-sulfur Batteries

With the progress of science and the development of human society, traditional energy is increasingly exhausted, and low energy density lithium ion battery is not enough to support the demand for energy, so the development of high capacity of clean energy system is imminent. Unlike Li-ion batteries, Li-sulfur batteries have a high specific energy density (2600 Wh(.)kg(-1)), making them a promising energy storage system. However, in oxidation-reduction reaction, the shuttle effect of intermediate polysulfides (LiPSs) and slow electrochemical reaction kinetics lead to severe degradation of the cathode and anode, resulting in rapid capacity decay. In this paper, a multifunctional FeP/carbon cloth (FeP/CC) interlayer was prepared by hydrothermal synthesis. The FeP grows evenly in a "needle" shape on a smooth carbon cloth. This structure provides more active sites for Li-S batteries and greatly improves the electrochemical reaction kinetics by utilizing the catalytic ability of phosphate to Li-S batteries. In addition, carbon cloth (CC), as the matrix, can also play the role of "physical domain limiting", thereby physically trapping LiPSs, inhibiting the shuttle effect and ensuring the cycle stability. In subsequent electrochemical tests, the FeP/CC interlayer lithium-sulfur battery had a first cycle discharge capacity of 1329 mAh(.)g(-1) and a reversible capacity of 1100 mAh(.)g(-1) after 100 cycles. When the sulfur load reaches 3.4 mg(.)cm(-2) and the current density is 1 C, the cyclic capacity is stable at 495 mAh(.)g(-1). In addition, FeP/CC showed excellent adsorption and catalytic conversion ability for LiPSs in visual adsorption experiments and ultraviolet spectrum tests. This multifunctional FeP/CC interlayer provides a feasible idea for the development of high stability and high capacity lithium-sulfur batteries.