Novel fusiform core-shell-MOF derived intact metal@carbon composite: An efficient cathode catalyst for aqueous and solid-state Zn-air batteries

Abstract Owing to the varied mechanisms of ORR/OER, exploiting cost-effective bifunctional catalysts with robust ORR/OER activities and excellent performances in Zn-air batteries is still a challenge. In this work, the Co/CoO@NSC bifunctional catalyst is obtained by using Zn-MOF@Co-MOF as self-template. The Co/CoO@NSC composite has interconnected porous architecture with intact metal@carbon structure, exhibiting superior electrocatalytic activities toward ORR and OER that can be comparable with the Pt/C and RuO2 catalysts, respectively. The Co/CoO@NSC-based aqueous Zn-air battery achieves a high specific capacity (759.7 mAh/g) and energy density (990.5 Wh/kg), and ultra-long rechargeable property (more than 400 h/1200 cycles). The Co/CoO@NSC-based solid-state Zn-air battery also delivers an excellent performance with a long cycle life (more than 143 h/858 cycles). Most importantly, the newly synthesized and recharged Co/CoO@NSC-based solid-state Zn-air battery can be used to light up a 2 V LED lamp for more than 28 h, demonstrating the superior practicability as rechargeable power source.