Oxygen vacancies-enriched CeO2-CoxOy heterostructures facilitate the “trapping-conversion” process of lithium polysulfides for high-performance Li-S batteries
Anran Gao, Qingzhong Wu, Hongli Chen, Yukun Pan, Bo Niu, Yayun Zhang, Donghui Long
Abstract
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.