An integrated bifunctional catalyst of metal-sulfide/perovskite oxide for lithium-oxygen batteries

The pursuit of efficient and durable bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is urgently needed for the development of highly reversible lithium-oxygen batteries. Perovskite oxides are emerging as a novel research frontier to simultaneously catalyze oxygen reduction and evolution reactions, however, their activity and durability are still far from desirable. Herein, we propose a rational design of Ni3S2 decorated double perovskite PrBa0.5Sr0.5Co2O5+δ as an integrated electrocatalyst. A Ni3S2 layer with 10 nm thickness is uniformly anchored on electrospun PrBa0.5Sr0.5Co2O5+δ nanofibers via the atomic layer deposition technology and the following sulfudation process. Notably, the lithium-oxygen batteries employing the as-prepared catalyst shows the excellent performance with a narrow overpotential (0.68 V at 1000 mAh g−1), a high capacity (12874 mAh g−1 at 100 mA g−1) as well as the improved cycle stability (over 120 cycles) and rate capacity. The outstanding performance arises from the synergistic coupling of Ni3S2 and PrBa0.5Sr0.5Co2O5+δ as well as the hierarchical porous structure with sufficient catalytic active sites. This work provides an innovative method to combine the metal chalcogenides and perovskite oxides, and the results suggest that the integrated Ni3S2/PrBa0.5Sr0.5Co2O5+δ has a great potential as bifunctional electrocatalyst for the reversible lithium-oxygen batteries. [Display omitted] •Hierarchical Ni3S2/PBSC NFs with core-shell structure have been fabricated.•Ni3S2/PBSC NFs exhibited enhanced ORR/OER activities.•The synergy of Ni3S2 and PBSC was responsible for the enhanced activities.•Ni3S2/PBSC based Li-O2 batteries showed improved performance.