Jin Zhaokui, Yang Mu, Wang Jingjing, Gao Hongyi, Lu Yunfeng, Wang Ge
School of Materials and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian district, 100083, P.R. China.
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA.
Chemistry. 2016 Apr 18;22(17):6031-6. doi: 10.1002/chem.201505099. Epub 2016 Mar 10.
Hierarchical and hollow nanostructures have recently attracted considerable attention because of their fantastic architectures and tunable property for facile lithium ion insertion and good cycling stability. In this study, a one-pot and unusual carving protocol is demonstrated for engineering hollow structures with a porous shell. Hierarchical TiO2 hollow spheres with nanosheet-assembled shells (TiO2 NHS) were synthesized by the sequestration between the titanium source and 2,2'-bipyridine-5,5'-dicarboxylic acid, and kinetically controlled etching in trifluoroacetic acid medium. In addition, annealing such porous nanostructures presents the advantage of imparting carbon-doped functional performance to its counterpart under different atmospheres. Such highly porous structures endow very large specifics surface area of 404 m(2) g(-1) and 336 m(2) g(-1) for the as-prepared and calcination under nitrogen gas. C/TiO2 NHS has high capacity of 204 mA h g(-1) at 1 C and a reversible capacity of 105 mA h g(-1) at a high rate of 20 C, and exhibits good cycling stability and superior rate capability as an anode material for lithium-ion batteries.
由于其奇妙的结构以及易于锂离子嵌入的可调性质和良好的循环稳定性，分级和中空纳米结构最近引起了广泛关注。在本研究中，展示了一种一锅法且不同寻常的刻蚀方案，用于构建具有多孔壳的中空结构。通过钛源与2,2'-联吡啶-5,5'-二羧酸之间的螯合作用以及在三氟乙酸介质中的动力学控制刻蚀，合成了具有纳米片组装壳的分级TiO₂中空球（TiO₂ NHS）。此外，对这种多孔纳米结构进行退火处理具有在不同气氛下赋予其碳掺杂功能特性的优势。对于所制备的样品以及在氮气气氛下煅烧后的样品，这种高度多孔的结构赋予了它们分别为404 m² g⁻¹和336 m² g⁻¹的非常大的比表面积。C/TiO₂ NHS作为锂离子电池的负极材料，在1 C时具有204 mA h g⁻¹的高容量，在20 C的高倍率下具有105 mA h g⁻¹的可逆容量，并且表现出良好的循环稳定性和优异的倍率性能。
