Regulating the polysulfide redox kinetics for high-performance lithium-sulfur batteries through highly sulfiphilic FeWO4 nanorods

Abstract Owing to their high theoretical capacity, energy density, good environmental protection, and low cost, lithium-sulfur batteries are regarded as extremely promising next-generation energy storage equipment for electrical and portable devices. However, their practical application is mainly hindered by the polysulfide shuttle and the slow redox kinetic in the electrochemical process. In this study, we prepared FeWO4 nanorods by a simple hydrothermal method to enhance the electrochemical performance of lithium-sulfur batteries. The FeWO4 nanorods act as catchers and electrocatalyst for polysulfide in lithium sulfur batteries. These FeWO4 nanorods could efficiently adsorb polysulfide and enhance the conduction of Li ions, leading to inhibition of the polysulfide shuttle effect and enhancement of the electrochemical reaction kinetic for cycling stability and rate performance. Density functional theory calculation shows the existence of the high binding energy between FeWO4 nanorods and polysulfide, which can limit polysulfide to the surface of FeWO4 nanorods. Therefore, the Li-S batteries with FeWO4 nanorods not only provide an initial discharge capacity of 1318 mAh g−1 at the current of 0.8 mA with high coulombic efficiency of 97%, but also shows a capacity decay rate of 0.07% during 600 cycles at a current of 3.2 mA. With the above-mentioned dates, this work offers a promising new strategy to regulate the kinetic behaviors of polysulfide for high-performance Li-S batteries.