Cupric oxide (CuO) represents an attractive anode material for sodium‐ion batteries owing to its large capacity (674 mAh g⁻¹) associated with multiple electron transfer. However, the substantial volume swelling and shrinking (≈170%) upon Na uptake and release, which mimics an electrode breathing process, disturbs the structural integrity, leading to poor electrochemical durability and low Coulombic efficiency. Here, a structural strategy to regulate the breathing of CuO nanoarray electrodes during Na cycling using an atomic layer deposition of cohesive TiO₂ thin films is presented. CuO nanoarrays are electrochemically grown on 3D Cu foam and directly used as anodes for sodium storage. The regulated CuO electrode arrays enable a large reversible capacity (592 mAh g⁻¹), a high cycle efficiency (≈100%), and an excellent cycling stability (82% over 1000 cycles), which are some of the best sodium storage performance values reported for CuO systems. Electrochemical impedance and microscopic examination reveal that the enhanced performance is a direct outcome of the efficient regulation of the breathing of CuO nanowires by TiO₂ layer.

中文翻译：

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呼吸式CuO纳米阵列电极对增强电化学钠存储的调节

氧化铜（CuO）由于具有大容量（674 mAh g ^-1）与多次电子转移有关，因此是钠离子电池的一种有吸引力的负极材料。但是，Na吸收和释放时的大量体积膨胀和收缩（≈170％）模仿了电极的呼吸过程，扰乱了结构完整性，导致电化学耐久性差和库仑效率低。在此，提出了一种结构策略，该策略使用粘性TiO ₂薄膜的原子层沉积来调节Na循环过程中CuO纳米阵列电极的呼吸。CuO纳米阵列在3D Cu泡沫上电化学生长，并直接用作钠存储的阳极。调节后的CuO电极阵列可实现大可逆容量（592 mAh g ^-1），高循环效率（≈100％）和出色的循环稳定性（在1000次循环中达到82％），这是CuO系统报道的最佳钠存储性能值。电化学阻抗和显微镜检查表明，增强的性能是TiO ₂层有效调节CuO纳米线呼吸的直接结果。