Thermoelectric Field Enhanced Sulfur Evolution Kinetics for High Performance Lithium-Sulfur Batteries

The practical deployment of lithium-sulfur (Li-S) batteries has been impeded by the shuttle effect and sluggish kinetics of lithium polysulfide (LiPSs) conversion. Here, Bi_0.5Sb_1.5Te₃/carbon nanotubes (BST/CNT) interlayer is designed to enhance the durability of Li-S batteries by providing extensive adsorption sites and generating a thermoelectric field from BST thermoelectric material. Experimental and density functional theory investigations confirm the superior adsorption properties of BST. Additionally, analyses using Gibbs free energy and cyclic voltammetry robustly demonstrate that the thermoelectric field significantly accelerates the conversion kinetics of LiPSs. The electrochemical performance of cells equipped with a 20% BST interlayer is exceptional, showing remarkable stability over 500 cycles at 1 C with a minimal capacity decay rate of 0.05% per cycle. Most importantly, the thermoelectric field substantially improves the conversion kinetics of LiPSs, allowing the cell to maintain a discharge capacity of 594 mAh g^-1 even at 10 C. Furthermore, under conditions of high sulfur loading (7.0 mg cm^-2) and low electrolyte-to-sulfur ratio (6.1 µL mg^-1), the cell achieves an areal capacity of 5.9 mAh cm^-2. This research not only evidences the effectiveness of the thermoelectric field in enhancing the conversion kinetics of LiPSs but also shows its potential to boost the performance of Li-S batteries.