Highly Ordered Single Crystalline Nanowire Array Assembled Three-Dimensional Nb3O7(OH) and Nb2O5 Superstructures for Energy Storage and Conversion Applications

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• 作者：Haimin Zhang ; Yun Wang ; Porun Liu ; Shu Lei Chou ; Jia Zhao Wang ; Hongwei Liu ; Guozhong Wang ; Huijun Zhao
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：507-514
• 全文大小：499K
• ISSN：1936-086X

文摘

Three-dimensional (3D) metal oxide superstructures have demonstrated great potentials for structure-dependent energy storage and conversion applications. Here, we reported a facile hydrothermal method for direct growth of highly ordered single crystalline nanowire array assembled 3D orthorhombic Nb₃O₇(OH) superstructures and their subsequent thermal transformation into monoclinic Nb₂O₅ with well preserved 3D nanowire superstructures. The performance of resultant 3D Nb₃O₇(OH) and Nb₂O₅ superstructures differed remarkably when used for energy conversion and storage applications. The thermally converted Nb₂O₅ superstructures as anode material of lithium-ion batteries (LiBs) showed higher capacity and excellent cycling stability compared to the Nb₃O₇(OH) superstructures, while directly hydrothermal grown Nb₃O₇(OH) nanowire superstructure film on FTO substrate as photoanode of dye-sensitized solar cells (DSSCs) without the need for further calcination exhibited an overall light conversion efficiency of 6.38%, higher than that (5.87%) of DSSCs made from the thermally converted Nb₂O₅ film. The high energy application performance of the niobium-based nanowire superstructures with different chemical compositions can be attributed to their large surface area, superior electron transport property, and high light utilization efficiency resulting from a 3D superstructure, high crystallinity, and large sizes. The formation process of 3D nanowire superstructures before and after thermal treatment was investigated and discussed based on our theoretical and experimental results.