Superoxide-based Na–O₂ batteries have been considered as some of the most promising candidates for next-generation energy storage systems due to their high theoretical energy density and energy efficiency. However, to fully realize the advantages of Na–O₂ batteries, the underutilization of air electrodes and poor cycling performance caused by limited O₂ transport in the air electrodes must be addressed. In this work, 3D printing of a reduced graphene oxide (rGO)-based air electrode with a hierarchical porous structure was first demonstrated as being “O₂ breathable” for Na–O₂ batteries. The unique cathode structure features noncompetitive and continuous pathways for O₂, Na⁺ ions, and electrons. The macropores provide smooth passages to facilitate O₂ access across the whole electrode, while the micropores between rGO sheets serve as electrolyte reservoirs and accommodate NaO₂. The efficiently packed rGO sheets ensure sufficient electronic conductivity within the 3D architecture. Na–O₂ batteries using these “O₂ breathable” electrodes can achieve a high capacity of 13484.6 mAh g^–1 at 0.2 A g^–1 and a stable cycling performance over 120 cycles with a cutoff capacity of 500 mAh g^–1 at 0.5 A g^–1. The 3D-printed “O₂ breathable” electrodes evidently demonstrate the importance of a refined balance between electronic conductivity and O₂ transport for high-performance Na–O₂ batteries.

中文翻译：

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自由站立的“ O ₂透气”空气电极的3D打印，用于大容量和长寿命的Na-O ₂电池

基于超氧化物的Na–O ₂电池由于具有较高的理论能量密度和能效，因此被认为是下一代储能系统最有希望的候选者。但是，要完全实现Na–O ₂电池的优势，必须解决空气电极的利用不足和空气电极中O ₂迁移受限导致的不良循环性能。在这项工作中，具有分层多孔结构的基于氧化石墨烯（rGO）的空气电极的3D打印首次被证明对Na-O ₂电池具有“ O ₂透气性” 。独特的阴极结构具有非竞争性和连续性的O ₂，Na途径⁺离子和电子。大孔提供了平滑的通道，以利于O ₂穿过整个电极，而rGO片之间的微孔充当了电解质的储藏室并容纳了NaO ₂。高效包装的rGO板可确保3D架构内具有足够的电子导电性。使用这些“ O ₂透气”电极的Na–O ₂电池在0.2 A g ^–1时可达到13484.6 mAh g ^–1的高容量，在120次循环中具有稳定的循环性能，在0.5时的截止容量为500 mAh g ^–1 A g ^–1。3D打印的“ O ₂“透气”电极显然证明了高性能Na–O ₂电池在电导率和O ₂传输之间保持平衡的重要性。