Dual-protected Co@PPD_rGO core@bishell nanomaterials as efficient bifunctional electrocatalysts for long-life rechargeable zinc–air battery

Abstract

Noble-metal free and durable electrocatalysts with high catalytic activity towards oxygen reduction and evolution reactions are crucial to achieving a high-performance rechargeable Zn–air battery. Herein, a bifunctional electrocatalyst with a dual-protected structure has been successfully fabricated. The obtained materials, i.e., Co@PPD_rGO, showed good ORR and OER performances. As a proof-of-concept application, Co@PPD_rGO was employed in the rechargeable Zn–air battery. It showed lower charge and discharge voltages compared with Pt/C under the same conditions. It should be noted that a voltage degradation is observed on Co@PPD_rGO after 350 cycles. These good performances originate from its 3D porous structure, dual protection from PPD and rGO, high specific surface area, small charge transfer resistance, the N/Co-doping effect and synergistic interaction between Co@PPD and rGO. This strategy reported herein may pave a way for designing efficient electrocatalysts toward Zn–air batteries using other dual-protected MOF materials.