Fang Hai-Tao, Liu Min, Wang Da-Wei, Sun Tao, Guan Dong-Sheng, Li Feng, Zhou Jigang, Sham Tsun-Kong, Cheng Hui-Ming
School of Materials Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001, People's Republic of China.
Nanotechnology. 2009 Jun 3;20(22):225701. doi: 10.1088/0957-4484/20/22/225701. Epub 2009 May 13.
Nanostructured amorphous and anatase TiO2 are both considered as high rate Li-insertion/extraction electrode materials. To clarify which phase is more desirable for lithium ion batteries with both high power and high density, we compare the electrochemical properties of anatase and amorphous TiO2 by using anodic TiO2 nanotube arrays (ATNTAs) as electrodes. With the same morphological features, the rate capacity of nanostructured amorphous TiO2 is higher than that of nanostructured anatase TiO2 due to the higher Li-diffusion coefficient of amorphous TiO2 as proved by the electrochemical impedance spectra of an amorphous and an anatase ATNTA electrode. The electrochemical impedance spectra also prove that the electronic conductivity of amorphous TiO2 is lower than that of anatase TiO2. These results are helpful in the structural and componential design of all TiO2 mesoporous structures as anode material in lithium ion batteries. Moreover, all the advantages of the amorphous ATNTA electrode including high rate capacity, desirable cycling performance and the simplicity of its fabrication process indicate that amorphous ATNTA is potentially useful as the anode for lithium ion batteries with both high power and high energy density.
纳米结构的非晶态和锐钛矿型TiO₂均被视为高倍率锂嵌入/脱出电极材料。为了明确哪种相对于兼具高功率和高能量密度的锂离子电池更具优势，我们以阳极TiO₂纳米管阵列（ATNTA）作为电极，比较了锐钛矿型和非晶态TiO₂的电化学性能。在具有相同形态特征的情况下，纳米结构的非晶态TiO₂的倍率性能高于纳米结构的锐钛矿型TiO₂，这是由于非晶态TiO₂具有更高的锂扩散系数，这一点已通过非晶态和锐钛矿型ATNTA电极的电化学阻抗谱得到证实。电化学阻抗谱还证明，非晶态TiO₂的电子电导率低于锐钛矿型TiO₂。这些结果有助于将所有TiO₂介孔结构设计为锂离子电池阳极材料的结构和成分。此外，非晶态ATNTA电极的所有优点，包括高倍率性能、良好的循环性能及其制备过程的简单性，表明非晶态ATNTA作为兼具高功率和高能量密度的锂离子电池阳极具有潜在的应用价值。
