Metal-air battery, represented by zinc-air battery (ZAB), is recognized as a promising secondary battery technology with great energy density. Since the catalyst in the air-electrode must simultaneously catalyze oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), mass transfer structure of the air-electrode catalyst would significantly affect the ZAB performance. A facile selectively etching strategy is therefore proposed to in situ adjusting the mass transfer structure of the CoFe OER/ORR bi functional catalyst encapsulated in graphene cage. This graphene encapsulated CoFe catalyst with optimized mass transfer channel exhibits superior OER and ORR activity to IrO₂ and Pt/C, respectively. The corresponding ZAB performance is therefore tripled compared with that equipped with Pt/C–IrO₂ catalysts in terms of maximum power density (206 mW/cm²). Together with the satisfied stability, this facilely synthesized CoFe catalyst shows promising application potential in metal-air batteries.

以锌空气电池（ZAB）为代表的金属空气电池被认为是一种有前途的，具有高能量密度的二次电池技术。由于空气电极中的催化剂必须同时催化氧释放反应（OER）和氧还原反应（ORR），因此空气电极催化剂的传质结构将显着影响ZAB的性能。因此，提出了一种简便的选择性蚀刻策略，以原位调节封装在石墨烯笼中的CoFe OER / ORR双功能催化剂的传质结构。这种石墨烯封装的CoFe催化剂具有最佳的传质通道，与IrO ₂相比，具有出色的OER和ORR活性和Pt / C。因此，相对于配备Pt / C–IrO ₂催化剂的ZAB性能，其最大功率密度（206 mW / cm ²）是其三倍。连同令人满意的稳定性，这种易于合成的CoFe催化剂在金属空气电池中显示出广阔的应用潜力。