Oxygen Vacancies Riched PrO_x Polycrystalline Nanorods on Graphene Nanosheets as Advanced Oxygen Catalysts for Lithium-Oxygen Batteries

The slow reaction kinetics of Li-O is currently the most pressing technical obstacle to the development of lithium-oxygen batteries. The Li2O2 ' s growth/decomposition pathways dominate the battery performance and can be optimized by exploring efficient cathode catalysts. Herein, we prepare regular, polycrystalline, oxygen vacancy (V-O)-riched PrOx uniformly anchored on few-layered graphene (FLG) nanosheets to boost the Li-O reactions. XRD, TGA, XPS, SEM, TEM, SEAD, and electrochemical test techniques are used to study their chemical composition, microstructure, battery performance, and the effect of FLG on the formation of polycrystalline and V-O. It is confirmed that FLG provides a large specific surface area and good electron transport. Moreover, it works as an anchoring substrate to transform PrOx from single crystal to polycrystalline, which is beneficial for exposing catalytic sites and V-O and improving the battery performance. This unique composition and structure offer efficient active sites, accelerate electron transport, and regulate the Li2O2 ' s nucleation to form nanofilms or nanosheets on the catalyst. With this cathode catalyst, the battery achieved an ultralow total overpotential of 0.618 V, with a discharge capacity of 11489 mAh g(-1) in the ultimate-capacity mode and a superior cyclability of 85 cycles under the limited capacity of 500 mAh g(-1).