▎ 摘　　要

The development of electrocatalysts with excellent OER and ORR performance is a significant challenge for the commercialization of metal-air batteries. We report Sm0.5Sr0.5Co0.2Fe0.8O3-delta (SSCF28) nanofibers modified by 3D nitrogen-doped graphene (3DNG) composite catalysts with different mass ratios of SSCF28/3DNG. In 0.1 M KOH electrolyte, SSCF28/3DNG with the optimal mass ratio (1:1) demonstrates the best oxygen electrocatalysis performance. The synergistic effect between SSCF and 3DNG benefits the electrocatalytic activities of OER and ORR.