The vital challenge of a layered manganese oxide cathode for sodium-ion batteries is its severe capacity degradation and sluggish ion diffusion kinetics caused by irreversible phase transitions. In response to this problem, the spinel-layered manganese-based composite with an intergrowth structure is ingeniously designed by virtue of an interesting spinel-to-layered transformation in the delithiated LiMn₂O₄ under Na⁺ insertion. This unique spinel-layered intergrowth structure is strongly confirmed by combining multiple structure analysis techniques. The layered component can provide more reversible capacity, while the spinel component is crucial for the stabilized crystal structure and accelerated ion diffusion kinetics. As an appealing cathode for sodium-ion batteries, the layered-spinel composite delivers a high reversible capacity of 180.9 mAh g^–1, excellent cycling stability, and superior rate capability with 55.7 mAh g^–1 at 12 C. Furthermore, the reaction mechanism upon Na⁺ extraction/insertion is revealed in detail by ex situ X-ray diffraction and X-ray photoelectron spectroscopy, indicating that Na⁺ ions can be accommodated by the layered structure at a low voltage and by the spinel at a high voltage. This study will provide a new idea for the rational design of an advanced cathode for sodium-ion batteries.

中文翻译：

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尖晶石层共生复合阴极，用于钠离子电池。

用于钠离子电池的层状锰氧化物阴极的关键挑战在于其严重的容量降低和不可逆的相变所导致的缓慢的离子扩散动力学。针对这一问题，通过在Na ⁺下脱锂的LiMn ₂ O _4中有趣的尖晶石-层间转变，巧妙地设计了具有共生结构的尖晶石层-锰基复合材料。插入。通过结合多种结构分析技术，强烈确认了这种独特的尖晶石层共生结构。层状组分可以提供更多的可逆容量，而尖晶石组分对于稳定的晶体结构和加速的离子扩散动力学至关重要。作为钠离子电池的阴极的吸引力，层状-尖晶石复合提供的180.9毫安g的高可逆容量^-1，优异的循环稳定性，和优异的倍率性能与55.7毫安克^-1在12℃。此外，该反应机理通过异位X射线衍射和X射线光电子能谱详细揭示了Na ^+的提取/插入后，表明Na ⁺层状结构在低压下可以容纳离子，而尖晶石可以在高压下容纳离子。这项研究将为合理设计钠离子电池高级阴极提供一个新思路。