Oxygen vacancies-enriched CeO2-CoxOy heterostructures facilitate the “trapping-conversion” process of lithium polysulfides for high-performance Li-S batteries

• Oxygen vacancies regulate the d-orbit electron density of oxide heterostructure . • Oxygen vacancies-enriched CeO 2 -CoO improves trapping-conversion process for LiPSs . • Full CeO 2 -CoO/rGO-based cell exhibits stable cycling at 1C. Oxygen vacancies can tune the electronic and catalytic properties of oxide heterostructures, but their actions on the lithium polysulfides (LiPSs) conversion in Li-S batteries remain largely unexplored. Herein, we develop an oxygen vacancies-enriched CeO 2 -CoO heterostructure that could accelerate the sulfur redox kinetics via rapid bidirectional catalytic process. The enrichment of oxygen vacancies enhances electron interactions between CeO 2 -CoO and LiPSs by regulating the d-orbit electron density within the oxide heterostructure. This regulation significantly improves both adsorption capacity and catalytic activity of CeO 2 -CoO heterostructure, thereby resulting in an efficient and sustainable “trapping-conversion” process for LiPSs. Consequently, Li-S battery with the oxygen vacancies-enriched CeO 2 -CoO modified separator exhibits a notable lithium-ion diffusion coefficient (D li + ) of 3.1*10 −5 cm 2 s −1 in the sulfur oxidation process, and a high initial specific capacity of 1450 mAh g −1 at 0.2C and an ultra-low-capacity decay rate of 0.04 % per cycle over 1000 cycles at 1C. The present work highlights the positive actions of oxygen vacancies in heterostructures on the LiPSs conversion, offering a new pathway to improve the performance of Li-S batteries.