Dual-enhancement on electrochemical performance with thioacetamide as an electrolyte additive for lithium-sulfur batteries

l Thioacetamide is applied to the electrolyte of lithium-sulfur battery. l Thioamides that contain primary-amine or secondary-amine groups are prone to generate recyclable materials. l Thioacetamide boosts the solubility of Li 2 S by intermolecular hydrogen bonds. l The employment of thioacetamide promotes electrochemical performance of Li-S batteries. Lithium-sulfur (Li-S) batteries with high theoretical specific capacity and ascendancy of raw materials are considered as a potential candidate for next-generation energy storage system. However, some intractable challenges, such as low sulfur utilization caused by the loss of active materials and surface passivation resulted from the deposition of insulating products, still hinder the practical application of lithium-sulfur batteries. Herein, various types of thioamides with different molecular structures are investigated as electrolyte additives to enhance the electrochemical performance of Li-S cells by adjusting the solubility of the final product, Li 2 S. It is demonstrated that the thioamides that contain hydrogen in primary-amine or secondary-amine groups are prone to generate recyclable active materials. Specifically, thioacetamide (TAA) as an electrolyte additive not only provides extra reversible capacity, but also boosts the solubility of Li 2 S by intermolecular hydrogen bonds, alleviating the passivation of the electrode and enhancing kinetics for the conversion of polysulfide to Li 2 S. Therefore, the cells with TAA additive exhibit superior cycle performance and rate performance.