Constructed the microflower-like NiFe 2 O 4 /CeO 2 composites with high concentration of oxygen vacancies to accelerate the three-phase reaction in lithium-oxygen batteries

The development of efficient catalysts to accelerate the three-phase reaction at the cathode side represents a crucial step in enhancing the performance of lithium-oxygen batteries (LOBs) with high energy density. In this study, NiFe O /CeO composites with an appropriate Ce concentration were prepared as cathode catalysts for LOBs, and the unique micro-flower structure maximally exposed the active sites of the materials. The catalyst cleverly integrates the excellent oxygen evolution reaction (OER) activity of NiFe O and the outstanding oxygen reduction reaction (ORR) activity of CeO . The high concentration of oxygen vacancies and the composite structure synergistically enhanced the charge transfer ability, altered the charge distribution of the active sites, and modulated the electronic structure of the material, thereby achieving an appropriate adsorption energy for oxygen-containing intermediates. Consequently, the composite material displays 343 stable cycles, a round-trip efficiency of 97.8 %, and a discharge specific capacity of 7478 mAh/g. Additionally, it exhibits fast charging and slow discharging capabilities for up to 726 h. This work offers insights into the design of efficient bifunctional cathode catalysts for LOBs.