Increasing both catalytic site accessibility and intrinsic activity of multishelled materials is critical to boost its efficiency for bifunctional oxygen electrocatalysis and initiate its application in metal–air batteries. Herein, a hierarchical porous double-shelled (Mg,Co)₃O₄ electrocatalyst with controllable Mg substitution is synthesized via a proposed in situ coordinating process. The hierarchical porosity optimizes the availability of active sites and broadens diffusion channels for oxygen species. Meanwhile, Mg substitution greatly increases electrical conductivity and realizes novel insight of tailoring lattice alkalinity. Specifically, Mg substitution positively influences oxygen electrocatalysis by inducing lattice buffer zones that promote hydroxyl detachment from nearby catalytic sites. As a result, the final hybrid of (Mg,Co)₃O₄ encapsulated in N-doped graphitized carbon affords superior bifunctional oxygen electrocatalytic activities, outperforming state-of-the-art noble-metal benchmarks. When serving as an air electrode in Zn–air batteries, a low charge–discharge gap and long-term cyclability for over 200 h are realized in ambient air.

中文翻译：

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金属-空气电池对双功能氧反应具有定制的格子碱度的分层多孔双壳电催化剂

增加多壳材料的催化位点可及性和固有活性对于提高其双功能氧电催化效率并启动其在金属-空气电池中的应用至关重要。此处，为分层多孔双壳（Mg，Co）₃ O _4。通过拟议的原位配位过程合成了可控的Mg取代的电催化剂。分层孔隙率优化了活性位点的可用性，并拓宽了氧物种的扩散通道。同时，Mg置换大大提高了电导率，并实现了调整晶格碱度的新颖见解。具体而言，Mg取代通过诱导晶格缓冲区促进氧从附近的催化部位脱离，从而积极地影响氧的电催化作用。结果，最终的（Mg，Co）₃ O ₄杂化物包封在N掺杂的石墨化碳中，具有出色的双功能氧电催化活性，优于最先进的贵金属基准。当用作Zn-空气电池中的空气电极时，在环境空气中实现了200h以上的低充放电间隙和长期可循环性。