Considering the abundance of iron and manganese within the Earth’s crust, the cathode O3-NaFe_0.5Mn_0.5O₂ has shown great potential for large-scale energy storage. Following the strategy of introducing specific heteroelements to optimize the structural stability for energy storage, the work has obtained an O3-type NaFe_0.4Mn_0.49Cu_0.1Zr_0.01O₂ that exhibits enhanced electrochemical performance and air stability. It displays an initial reversible capacity of 147.5 mAh g^–1 at 0.1C between 2 and 4.1 V, a capacity retention ratio exceeding 69.6% after 100 cycles at 0.2C, and a discharge capacity of 70.8 mAh g^–1 at a high rate of 5C, which is superior to that of O3-NaFe_0.5Mn_0.5O₂. The codoping of Cu/Zr reserves the layered O3 structure and enlarges the interlayer spacing, promoting the diffusion of Na⁺. In addition, the structural stability and air stability observed by Cu-doping is well maintained via the incorporation of extra Zr favoring a highly reversible phase conversion process. Thus, this work has demonstrated an efficient strategy for developing cobalt/nickel-free high-capacity and air-stable cathodes for sodium-ion batteries.

中文翻译：

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铜和锆共掺杂 O3 型氧化铁锰钠作为钠离子电池的无钴/镍高容量和空气稳定阴极

考虑到地壳中丰富的铁和锰，阴极O3-NaFe _0.5 Mn _0.5 O ₂已显示出大规模储能的巨大潜力。遵循引入特定异质元素以优化储能结构稳定性的策略，该工作获得了具有增强电化学性能和空气稳定性的 O3 型 NaFe _0.4 Mn _0.49 Cu _0.1 Zr _0.01 O ₂。它在 2 和 4.1 V 之间在 0.1C 下显示出 147.5 mAh g ^–1的初始可逆容量，在 0.2C 下循环 100 次后容量保持率超过 69.6%，放电容量为 70.8 mAh g^–1 5C的高倍率，优于O3-NaFe _0.5 Mn _0.5 O ₂。Cu/Zr的共掺杂保留了层状O3结构，增大了层间距，促进了Na ⁺的扩散。此外，通过掺入额外的 Zr 有利于高度可逆的相转化过程，Cu 掺杂观察到的结构稳定性和空气稳定性得到了很好的保持。因此，这项工作证明了开发用于钠离子电池的无钴/镍的高容量和空气稳定阴极的有效策略。