Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures
Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures
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DOI：
10.1016/j.jpowsour.2011.06.006
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发表时间：
2011-10
影响因子：
9.2
通讯作者：
Feng Zhang;Yu Zhang;Shuyan Song;Hongjie Zhang
中科院分区：
文献类型：
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作者：
Feng Zhang;Yu Zhang;Shuyan Song;Hongjie Zhang
采用模板辅助法和水热法设计了具有可控尺寸和层次化纳米结构的介孔空心tio2微球。结果表明，由介孔纳米微球组成的空心微球在0.25C时具有非常稳定的184mAhg−1可逆容量，在10C的高速率下具有极高的122mAhg−1功率。高效的层次化纳米结构使样品具有优异的高速率和高容量性能。空心结构可以缩短锂离子在微球中的扩散时间。介孔纳米球之间的大介孔通道提供了一个易于访问的系统，促进了电解质在电极材料内的运输和锂离子的扩散。充满介孔通道的电解质也会导致较高的电解质/电极接触面积，从而促进锂离子在电解质/电极界面上的传输。介孔纳米球中细小的介孔使得电解质和锂离子进一步扩散到电极材料内部，增加了电解质/电极的接触面积。小的纳米颗粒也可以保证高的可逆容量。
Mesoporous hollow TiO2microspheres with controlled size and hierarchical nanostructures are designed from a process employing in suit template-assisted and hydrothermal methods. The results show that the hollow microspheres composed of mesoporous nanospheres possess very stable reversible capacity of 184mAhg−1at 0.25C and exhibit extremely high power of 122mAhg−1at the high rate of 10C. The superior high-rate and high-capacity performance of the sample is attributed to the efficient hierarchical nanostructures. The hollow structure could shorten the diffusion length for lithium ion in the microspheres. The large mesoporous channels between the mesoporous nanospheres provide an easily-accessed system which facilitates electrolyte transportation and lithium ion diffusion within the electrode materials. The electrolyte, flooding the mesoporous channels, can also lead to a high electrolyte/electrode contact area, facilitating transport of lithium ions across the electrolyte/electrode interface. The small mesopores in the meosporous nanospheres can make the electrolyte and lithium ion further diffuse into the interior of electrode materials and increase electrolyte/electrode contact area. The small nanoparticles can also ensure high reversible capacity.