Sodium‐ion batteries have attracted ever‐increasing attention in view of the natural abundance of sodium resources. Sluggish sodiation kinetics, nevertheless, remain a tough challenge, in terms of achieving high rate capability and high energy density. Herein, a sheet‐in‐sphere nanoconfiguration of 2D titania–carbon superlattices vertically aligned inside of mesoporous TiO₂@C hollow nanospheres is constructed. In such a design, the ultrathin 2D superlattices consist of ordered alternating monolayers of titania and carbon, enabling interpenetrating pathways for rapid transport of electrons and Na⁺ ions as well as a 2D heterointerface for Na⁺ storage. Kinetics analysis discloses that the combination of 2D heterointerface and mesoporosity results an intercalation pseudocapacitive charge storage mechanism, which triggers ultrafast sodiation kinetics. In situ transmission electron microscope imaging and in situ synchrotron X‐ray diffraction techniques elucidate that the sheet‐in‐sphere architecture can maintain robust mechanical and crystallographic structural stability, resulting an extraordinary high rate capability, remarkable stable cycling with a low capacity fading ratio of 0.04% per cycle over 500 cycles at 0.2 C, and exceptionally long‐term cyclability up to 20 000 cycles at 50 C. This study offers a method for the realization of a high power density and long‐term cyclability battery by designing of a hierarchical nanoarchitecture.

中文翻译：

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将超薄二维超晶格限制在中孔空心球中可提供超快和高容量的钠离子存储

鉴于钠资源的自然丰富性，钠离子电池吸引了越来越多的关注。然而，就获得高速率能力和高能量密度而言，缓慢的发酵动力学仍然是一个艰巨的挑战。在此，构造了在介孔TiO ₂ @C中空纳米球内部垂直排列的二维二氧化钛-碳超晶格的片中球纳米结构。在这样的设计中，超薄2D超晶格包括二氧化钛和碳的交替有序单层的，使互穿途径的电子和Na的快速运输⁺离子以及作为2D异质界面的Na ⁺存储。动力学分析表明，二维异质界面和介孔率的组合会导致插层伪电容电荷存储机制，从而触发超快的胶结动力学。原位透射电子显微镜成像和原位同步加速器X射线衍射技术阐明了片内球形结构可以保持鲁棒的机械和晶体学结构稳定性，从而产生了非凡的高倍率性能，显着的稳定循环以及低的容量衰减比。在0.2 C的500个循环中，每个循环的0.04％，以及在50 C的情况下高达20000个循环的长期长期可循环性。这项研究提供了一种通过设计分层结构来实现高功率密度和长期可循环性电池的方法纳米结构。