Assembled hollow spheres with CoFe alloyed nanocrystals encapsulated in N, P-doped carbon nanovesicles: An ultra-stable bifunctional oxygen catalyst for rechargeable Zn-air battery

Exploring efficient, cost-effectiveness and stable bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for rechargeable metal-air batteries. Herein, CoFe alloyed nanocrystals encapsulated in N, P-codoped carbon nanovesicles assembled hollow spheres (CoFe@NP-CHS) are prepared by pyrolyzing the homogenous mixture of vitamin B12 (VB12), melamine and Fe2O3 at 700 degrees C. The resultant CoFe@NP-CHS demonstrates distinct activity for ORR and OER in the alkaline media. More impressively, the as-developed Zn-air battery displays excellent performance with enhanced open-circuit voltage of 1.516 V, enlarged peak power density of 123.1 mW cm(-2), and remarkable cycling stability at 10 mA cm(-2) (40 h), outperforming the mixture of commercial Pt/C + RuO2 catalysts. This work provides a promising avenue to fabricate efficient, low cost and stable electrocatalyst for practical viability in electrochemical energy devices.