A two-dimensional (2D) SnNb2O6/amino-functionalized graphene (En-RGO) nanocomposite with a representative 2D–2D architecture has been constructed by an easy self-assembly approach and firstly investigated as anode materials for secondary sodium-ion batteries. The SnNb2O6 nanosheets are evenly anchored with the amino-functionalized graphene through electrostatic attractive interplay between the negatively charged SnNb2O6 and positively charged En-RGO after modification. As a result, a remarkable reversible capacity of 300 mAh·g−1 was obtained at 50 mA·g−1, and significantly, the En-RGO electrode could also deliver ultra-long calendar life up to 1900 cycles with a high reversible capacity of 200 mAh·g−1 at current of 500 mA·g−1. Such excellent electrochemical characteristics can be mainly ascribed to its fast pseudo-capacitive energy storage mechanism, and the capacitive contribution can even reach up to 90% at 1.2 mV·s−1.

中文翻译：

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自组装合成SnNb2O6/氨基功能化石墨烯纳米复合材料作为钠离子电池的高倍率负极材料

通过简单的自组装方法构建了具有代表性 2D-2D 结构的二维 (2D) SnNb2O6/氨基功能化石墨烯 (En-RGO) 纳米复合材料，并首次将其用作二次钠离子电池的负极材料。SnNb2O6 纳米片通过修饰后带负电的 SnNb2O6 和带正电的 En-RGO 之间的静电吸引相互作用与氨基功能化石墨烯均匀锚定。结果，在 50 mA·g-1 下获得了 300 mAh·g-1 的显着可逆容量，并且值得注意的是，En-RGO 电极还可以提供高达 1900 次循环的超长日历寿命和高可逆容量在 500 mA·g-1 的电流下为 200 mAh·g-1。