Hierarchical mesoporous S,N-codoped carbon nanostructures composed of Co/Co-Cu-S/carbon nanoplate arrays on carbon nanofibers as a self-supported air cathode for long-lasting rechargeable Zn-air batteries

One of the primary roadblocks to widespread applications of rechargeable Zn-air batteries is the durability issue with oxygen reduction and evolution processes (ORR/OER) bifunctional electrocatalysts. We herein report the construction of a self-supported air cathode for Zn-air batteries made of S,N-codoped porous complex carbon nanostructures of Co/Co-Cu-S/carbon nanoplate arrays and carbon nanofibers (denoted as Co/Co-Cu-S@SNPCP-CFs). The hierarchical heteroatom-doped mesoporous carbon nanohybrids with multiple active species not only provide a high surface-to-volume ratio, exposing more catalytic sites and accelerating the charge and mass transfer, but also boost the activity and durability. The Co/Co-Cu-S@SNPCP-CFs catalyst reveals a small potential gap (ΔE=0.67 V) between the half-wave potential of ORR and OER potential at 10 mA cm−2, demonstrating outstanding bifunctional performance. Furthermore, the rechargeable Zn-air battery made with the as-obtained electrocatalyst exhibits a high-power density of 220 mW cm−2 and a long cycling time of over 800 h at 10 mA cm−2, and the flexible solid state rechargeable Zn-air battery based on Co/Co-Cu-S@SNPCP-CFs self-supporting air cathode also displays a long duration time of over 60 h.