TiO 2 nanotube arrays annealed in CO exhibiting high performance for lithium ion intercalation (original) (raw)
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TiO2 Nanotube Arrays Annealed in N2 for Efficient Lithium-Ion Intercalation
Journal of Physical Chemistry C, 2008
Anatase titania nanotube arrays were fabricated by means of anodization and annealed at 300, 400, and 500°C in N 2 . Lithium-ion intercalation measurements revealed that annealing in nitrogen resulted in much enhanced lithium-ion insertion capacity and improved cyclic stability. TiO 2 nanotube arrays annealed at 300°C exhibited the best lithium-ion intercalation property with an initial high discharge capacity up to 240 mA · h/g at a high current density of 320 mA/g. The excellent discharge capacity at a high charge/discharge rate could be attributed to the large surface area of the nanotube arrays and a short facile diffusion path for lithium-ion intercalation as well as improved electrical conductivity. As the annealing temperature increased, the discharge capacity decreased, but the cyclic stability improved; 400°C annealed TiO 2 nanotube arrays possessed an initial discharge capacity of 163 mA · h/g and retained 145 mA · h/g at the 50th cycle. The relationship between the annealing conditions, microstructure, and lithium-ion intercalation properties of TiO 2 nanotube arrays was discussed.
Insertion of lithium ion in anatase TiO 2 nanotube arrays of different morphology
Journal of Alloys and Compounds
Anatase TiO 2 nanotube arrays of different morphology were prepared by a two-step process: anodic oxidation at voltages 20-60V and subsequent annealing at 400 o C. By amplifying anodization voltage the inner diameter of nanotubes increased. At 60V nanotubes changed the shape from cylindrical tube to truncated cone with elliptical opening. Electrochemical insertion of Li-ion in nanotubes was studied by cyclic voltammetry and galvanostatic charge-discharge experiments. The cyclovoltammetric response was fast for all nanotube arrays. The galvanostatic areal charge/discharge capacity of nanotube arrays increased with increasing anodizaton voltage. Although the mass of nanotubes prepared at 45 V was larger, the gravimetrical capacity was much higher for nanotubes prepared at 60 V because of the larger surface area exposed to the electrolyte. Gravimetrical capacity values exceed theoretical bulk capacity of anatase due to the surface storage of Li-ion. Diffusion coefficient of Li-ion was calculated to be between 5.9•10-16 and 5.9•10-15 cm 2 •s-1. *Manuscript Click here to view linked References
J. of Electrical Engineering, 2016
TNAs (Titanium dioxide nanotube arrays) were synthesized by electrochemical anodization and these TNAs were annealed in different gas atmosphere such as argon, air, hydrogen and nitrogen. This annealing in different atmosphere brought variation in crystallite size (27 ~ 33 nm), which influences on electrochemical properties. The specific capacity of Ar, Air, N 2 and H 2-annealed TNAs was around ~165, 185, 177 and 190 mAh g-1 , respectively. The crystallite size of anatase TNAs seemed to be responsible for the change in lithium storage capacity, indicating that structural changes of TNAs were playing major role in electrochemical properties.
Self-organized TiO2/CoO nanotubes as potential anode materials for lithium ion batteries
Electrode material characteristics need to be improved urgently to fulfill the requirements for high performance lithium ion batteries. Herein, we report the use of the two-phase alloy Ti80Co20 for the growth of Ti-Co-O nanotubes (NT) employing an anodic oxidation process in a formamide-based electrolyte containing NH4F. The surface morphology and the current density for the initial nanotube formation are found to be dependent on the crystal structure of the alloy phases. XPS analyses of the grown nanotube arrays along with the oxidation state of the involved elements confirmed the formation of TiO2/CoO nanotubes under the selected process conditions. The electrochemical performance of the grown nanotubes was evaluated against a Li/Li+ electrode at different current densities of 10 – 400 µA cm-2. The results revealed that TiO2/CoO nanotubes prepared at 60 V exhibited the highest areal capacity of ~ 600 µAh cm-2 (i.e. 315 mAh g-1) at a current density of 10 µA cm-2. At higher current densities TiO2/CoO nanotubes showed nearly doubled lithium ion intercalation and a coulombic efficiency of 96 % after 100 cycles compared to lower effective TiO2 nanotubes prepared under identical conditions. The observed enhancement in the electrochemical performances could be attributed to increasing Li ion diffusion resulting from the presence of CoO nanotubes and the high surface area of the grown oxide tubes. The TiO2/CoO electrodes preserved their tubular structure after electrochemical cycling with only little changes in morphology.
Carbon-Coated Anatase TiO2 Nanotubes for Li-and Na-Ion Anodes
Carbon-coated, anatase titanium dioxide nanotubes were prepared by carbonizing a polyacrylonitrile-based block copolymer grafted on the as-synthesized titanate nanotubes. As revealed by high resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS), this approach results in a very homogeneous and thin carbon coating, which is advantageous for those active materials storing lithium without undergoing significant volume changes upon ion (de-)insertion. As a matter of fact, thus prepared carbon-coated TiO 2 nanotubes presented an excellent long-term cycling stability for more than 500 cycles (0.02% capacity fading per cycle) and a very promising high rate performance (about 130 and 110 mAh g −1 at 10 C and 15 C, respectively). The influence of the tubular morphology on the rate performance is briefly discussed by comparing carbon-coated nanotubes and nanorods. Finally, the carbon-coated nanotubes were also investigated as sodium-ion anode material, showing very promising reversible capacities of around 170, 120, and 100 mAh g −1 at C/10, 1 C, and 2 C, respectively, rendering them as versatile anode material for lithium-and sodium-ion applications
Cathodic titania nanotube arrays as anode material for lithium-ion batteries
Journal of Materials Science, 2016
The titanium dioxide nanotube arrays (TNAs) have been synthesized at cathode and anode via standard electrochemical method for their subsequent use as anode material for lithium-ion batteries (LIBs). The TNAs fabricated at cathode have higher Ti 3? in comparison to TNAs at anode, which was confirmed using X-ray photoelectron spectroscopy and Raman spectrometry. Moreover, the lattice parameters of cathodic TNAs are estimated via Rietveld refinement of X-ray diffraction, which also conform to Ti 3? doping and insertion of protons (H ?). The electrochemical impedance spectroscopy hints an increment in the electronic conductivity of TNAs fabricated at cathode. As a result, high reversible arealspecific capacity (*385.5 lAh cm-2 at 100 lA cm-2) with excellent rate capability is acquired by utilizing TNAs fabricated at cathode as anode material in LIBs.
Nanotechnology, 2009
Nanostructured amorphous and anatase TiO 2 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 TiO 2 by using anodic TiO 2 nanotube arrays (ATNTAs) as electrodes. With the same morphological features, the rate capacity of nanostructured amorphous TiO 2 is higher than that of nanostructured anatase TiO 2 due to the higher Li-diffusion coefficient of amorphous TiO 2 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 TiO 2 is lower than that of anatase TiO 2. These results are helpful in the structural and componential design of all TiO 2 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.
2021
Latest since the commercialization of lithium-ion batteries (LIBs) in 1991, a plethora of potential active materials have been investigated, targeting reduced cost as well as further improved energy and power densities, cycle life, safety, and sustainability. Of particular interest have been environmental benign and abundant titanium oxides such as Li4Ti5O12 (LTO) and TiO2, as they are characterized by a very little-to-essentially negligible volume variation upon de-/lithiation and offer very good rate capabilities as well as suitably high capacities at elevated de-/lithiation potentials of about 1.6 V (LTO) and 1.9 V (exemplarily for anatase TiO2) versus Liþ/Li, thus offering an intrinsic safety feature with regard to the risk of potential lithium plating. However, while LTO is already used in commercial LIBs, Li-free TiO2 is still at the research level—not least due to the greater variety in available polymorphs, i.e., anatase, rutile, and TiO2(B), to name just the most investigat...
Recent progress in Li-ion batteries with TiO2 nanotube anodes grown by electrochemical anodization
Rare Metals, 2020
Self-organized titanium dioxide (TiO 2) nanotubes, which are prepared by electrochemical anodizing, have been widely researched as promising anodes for Liion batteries. Both nanotubular morphology and bulk structure of TiO 2 nanotubes can be easily changed by adjusting the anodizing and annealing parameters. This is provided to investigate different phenomena by selectively adjusting a specific parameter of the Li ? insertion mechanism. In this paper, we reviewed how the morphology and crystallography of TiO 2 nanotubes influence the electrochemical performance of Li ? batteries. In particular, electrochemical performances of amorphous and anatase titanium dioxide nanotube anodes were compared in detail. As we all know, TiO 2 nanotube anodes have the advantages of nontoxicity, good stability, high safety and large specific surface area, in lithium-ion batteries. However, they suffer from poor electronic conductivity, inferior ion diffusivity and low theoretical capacity (335 mAhÁg-1), which limit their practical application. Generally, there are two ways to overcome the shortcomings of titanium dioxide nanotube anodes, including doping and synthesis composites. The achievements and existing problems associated with doped TiO 2 nanotube anodes and composite material anodes are summarized in the present review. Based on the analysis of lithium insertion mechanism of titanium dioxide nanotube electrodes, the prospects and possible research directions of TiO 2 anodes in lithiumion batteries are discussed.
Materials, 2017
TiO 2 nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li + ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs)@TiO 2 /CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO 2 /CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO 2 and TiO 2 /CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li + ion diffusivity, promoting a strongly favored lithium insertion into the TiO 2 /CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability.