Comparison of the rate capability of nanostructured amorphous and anatase TiO₂for lithium insertion using anodic TiO₂nanotube arrays

Abstract

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.

High specific capacity of TiO2-graphene nanocomposite as an anode material for lithium-ion batteries in an enlarged potential window

“…However, its practical capacity and high-rate capability are limited due to the low Li-ion diffusivity and electronic conductivity during reversible Li-ion insertion/extraction process [4][5][6]. In order to improve the electrochemical performance of TiO 2 materials, nanotechnology has been explored to provide increased reaction active sites and short diffusion lengths for electron and Li-ion transport [7][8][9][10][11][12][13]. In addition, a variety of approaches have also been developed to increase the electronic conductivity of the TiO 2 , such as adding conductive agents (e.g.…”

Phases Hybriding and Hierarchical Structuring of Mesoporous TiO2 Nanowire Bundles for High‐Rate and High‐Capacity Lithium Batteries

“…Recently, it has been reported that nanostructured rutile can strongly enhance both the capacity and the rate capability,14, 26 indicating that the nanosized rutile structures could be the promising anode materials. Moreover, it has been shown that the presence of high surface amorphous TiO 2 can enhance the Li ions storage capacities owing to a pseudocapacitance effect 25, 26, 27, 28. Finally, the presence of straight nanochannels is also very favorable for Li ions diffusion 30.…”

“…As mentioned above, anatase and rutile phases exist and alternatively appear in the same nanowire frequently, and amorphous is at the surface of the nanowires (Figures 1, S3, Supporting Information). Thus, the formed amorphous/crystalline hybrid nanowires are normally the reason for the very short plateau and the long sloped behavior of discharge processes 9, 26, 27. Due to this special superstructure, it was highly reversible during the following discharge–charge cycles, leading to an excellent capacity retention rate.…”

“…In addition, the amorphous phase of TiO 2 has recently aroused much attention for improving the capacities of the electrode materials26, 27, 28, 29 in spite of the fact that the amorphous phase may not be stable enough for the electrochemical reaction. Borghols et al28 prepared amorphous TiO 2 from the hydrolysis of titanium isopropoxide.…”

Characterization of Micron-Scale Nanotublar Super Dielectric Materials

“…Anodizing methods for creating nanofeatured films on titanium substrates have been extensively studied under a variety of similar conditions [61], [87][88][89][90][91][92][93][94]. The varying methods differ in substrate thickness, surface preparation, electrolyte composition, electrolyte concentration, anodizing potential, and anodizing duration.…”