Oxygen vacancy modified cerium dioxide with excellent catalytic activity for room-temperature Na S batteries
Wenqi Li, Ting Wang, Gang Yang, Runze Ma, Wenzhuo Li, Yujun Fu, Liang Wu, Zi‐Jiang Liu, Dequan Liu, Ying Wu, Deyan He
Abstract
Room-temperature sodium‑sulfur (RT Na S) batteries face challenges of severe shuttle effect and sluggish redox kinetics with low reversible capacity and fast capacity decay, which hinder their practical application. Herein, under the guidance of theoretical calculation, an efficient catalyst of cerium dioxide with oxygen vacancies (CeO 2- x ) embedded in porous carbon matrix delivering moderate adsorption ability and excellent catalytic active for sodium polysulfides (NaPSs) was designed and synthesized. The theoretical calculation shows that the decrease of band gap caused by creating oxygen vacancy, the electron donor of Ce element accompanying the oxygen vacancy and the lower dissociation barrier of Na 2 S 2 make CeO 2- x catalyst have satisfactory adsorption ability and catalytic activity. Profiting from these merits, the prepared S@PC/CeO 2- x cathodes of Na S batteries exhibit superior long cycle stability. After 200 cycles at 0.5 A g −1 , the capacity is 906 mAh g −1 . When the current density is increased to 1 A g −1 , the capacity remains at 701 mAh g −1 after 300 cycles. The adsorption-catalytic mechanism of NaPSs obtained experimentally and theoretically provides a new insight into the realization of high-performance RT Na S batteries.