Growth and Electrochemical Properties of V2O5 Nanotube Arrays

2005 ◽  
Vol 879 ◽  
Author(s):  
Ying Wang ◽  
Katsunori Takahashi ◽  
Huamei Shang ◽  
Kyoungho Lee ◽  
Guozhong Cao
Keyword(s):  
Electrochemical Properties ◽  
Nanotube Arrays ◽  
Outer Diameter ◽  
Nanotube Array ◽  
Redox Cycles ◽  
Inner Diameter ◽  
Electrochemical Redox ◽  
Li Ion ◽  
Ion Intercalation ◽  
Initial Capacity

AbstractNanotube arrays of amorphous vanadium pentoxide (V2O5) were synthesized through the template-based electrodeposition and its electrochemical properties were investigated for Li-ion intercalation applications. The nanotubes have a length of 10 μm, outer-diameter of 200 nm and inner-diameter of 100 nm. Electrochemical analyses demonstrate that the V2O5 nanotube array delivers a high initial capacity of 300 mAh/g, about twice that of the electrochemically-prepared V2O5 film. Although the V2O5 nanotube array shows a more drastic degradation than the film under electrochemical redox cycles, the nanotube array reaches a stabilized capacity of 160 mAh/g which remains about 1.3 times the stabilized capacity of the film.

scholarly journals Synthesis and Electrochemical Properties of InVO4 Nanotube Arrays

2006 ◽  
Vol 922 ◽  
Author(s):  
Ying Wang ◽  
Guozhong Cao
Keyword(s):  
Substrate Surface ◽  
Lithium Ion ◽  
Nanotube Arrays ◽  
Outer Diameter ◽  
Diffusion Distance ◽  
Nanotube Array ◽  
Charge Capacity ◽  
Polycarbonate Membranes ◽  
Ion Intercalation ◽  
Short Diffusion Distance

AbstractA capillary-enforced template-based method is described for the preparation of InVO4 nanotube arrays. Nanotube arrays of InVO4 were prepared by filling the InVO4 sol into pores of polycarbonate membranes and pyrolyzing through sintering. Another type of InVO4 nanotube arrays (InVO4/acac) are obtained from the sol with the addition of acetylene acetone (acac). For comparison purposes, InVO4 films were prepared by drop casting from InVO4 same sol. Films and the two types of nanotube arrays of InVO4 annealed at 500°C consist of mixed monoclinic (InVO4-I) and orthorhombic (InVO4-III) phases. Scanning electron microscopy (SEM) characterizations indicate that the nanotubes are well-aligned, perpendicular to substrate surface with the outer diameter of ~200 nm for short InVO4 nanotubes and ~170 nm for long InVO4 nanotubes. Chronopotentiometry results reveal that InVO4/acac nanotube array has the highest charge capacity (790 mAh/g), followed by InVO4 nanotube array (600 mAh/g) then InVO4 film (290 mAh/g). Such enhanced lithium-ion intercalation properties are ascribed to the large surface area and short diffusion distance offered by nanostructures and amorphisation caused by acetylene acetone in the case of InVO4/acac nanotube arrays.

Amorphous and Crystalline TiO2 Nanotube Arrays for Enhanced Li-ion Intercalation Properties

2010 ◽  
Vol 1266 ◽  
Author(s):  
Dongsheng Guan ◽  
Chuan Cai ◽  
Ying Wang
Keyword(s):  
Current Density ◽  
Electrode Materials ◽  
Nanotube Arrays ◽  
Outer Diameter ◽  
Compact Layer ◽  
Self Organized ◽  
Battery Electrode ◽  
Li Ion ◽  
Ion Intercalation ◽  
A Current

AbstractWe have employed anodic oxidation of Ti foils to prepare self-organized TiO2 nanotube arrays which show enhanced electrochemical properties for applications as Li-ion battery electrode materials. The lengths and pore diameters of TiO2 nanotubes can be finely tuned by varying voltage, electrolyte composition, or anodization time. The as-prepared nanotubes are amorphous and can be converted into anatase nanotubes with heat treatment at 480oC and nanotubes of mixed anatase/rutile phases by heating at 580oC. The morphological features of nanotubes remain unchanged after annealing. Amorphous nanotubes with a length of 3.0 μm and an outer diameter of 125 nm delivers a capacity of 91.2 μA h cm-2 at a current density of 400 μA cm-2, while those with a length of 25 μm and an outer diameter of 158 nm display a capacity of 533 μA h cm-2. The 3-μm long anatase nanotubes and nanotubes of mixed phases show lower capacities of 53.8 μA h cm-2 and 63.1 μA h cm-2, respectively at the same current density. The amorphous TiO2 nanotubes with a length of 1.9 μm exhibit a capacity five times higher than that of TiO2 compact layer even when the nanotube array is cycled at a current density 80 times higher than that for the compact layer. The amorphous nanotubes show excellent capacity retention ability over 50 cycles. Cycled nanotubes show little change in morphology compared to the nanotubes before cycling, indicating the high structural stability of TiO2 nanotubes.

Effect of Size of TiO2(B) Nanosheets on Electrochemical Properties for Fast Li Ion Intercalation

2020 ◽  
Vol MA2020-02 (3) ◽  
pp. 554-554
Author(s):  
Sho Hideshima ◽  
Itsuki Nagatani ◽  
Daisuke Takimoto ◽  
Wataru Sugimoto
Keyword(s):  
Electrochemical Properties ◽  
Li Ion ◽  
Ion Intercalation

Crystallization and high-temperature structural stability of titanium oxide nanotube arrays

2003 ◽  
Vol 18 (1) ◽  
pp. 156-165 ◽  
Author(s):  
Oomman K. Varghese ◽  
Dawei Gong ◽  
Maggie Paulose ◽  
Craig A. Grimes ◽  
Elizabeth C. Dickey
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Titanium Oxide ◽  
Elevated Temperatures ◽  
Anatase Phase ◽  
Argon Atmosphere ◽  
Nanotube Arrays ◽  
Nanotube Array ◽  
Inner Diameter ◽  
The Stability

The stability of titanium oxide nanotube arrays at elevated temperatures was studied in dry oxygen as well as dry and humid argon environments. The tubes crystallized in the anatase phase at a temperature of about 280 °C irrespective of the ambient. Anatase crystallites formed inside the tube walls and transformed completely to rutile at about 620 °C in dry environments and 570 °C in humid argon. No discernible changes in the dimensions of the tubes were found when the heat treatment was performed in oxygen. However, variations of 10% and 20% in average inner diameter and wall thickness, respectively, were observed when annealing in a dry argon atmosphere at 580 °C for 3 h. Pore shrinkage was even more pronounced in humid argon environments. In all cases the nanotube architecture was found to be stable up to approximately 580 °C, above which oxidation and grain growth in the titanium support disrupted the overlying nanotube array.

Electrochemical Properties of Highly Ordered TiO2 Nanotube Arrays as an Anode Material for Lithium-Ion Batteries

2011 ◽  
Vol 130-134 ◽  
pp. 1281-1285 ◽  
Author(s):  
Li Li Wang ◽  
Shi Chao Zhang ◽  
Xiao Meng Wu
Keyword(s):  
Electrochemical Properties ◽  
Coulombic Efficiency ◽  
Rate Capability ◽  
Lithium Ion ◽  
High Rate ◽  
Nanotube Arrays ◽  
Rate Performance ◽  
Treatment Rate ◽  
High Rate Capability ◽  
Nanotube Array

Well-aligned TiO2 nanotube arrays were fabricated from anodization by a subsequent heat treatment. Rate performance and electrochemical properties of TiO2 nanotube arrays were studied intensively. The electrode exhibits excellent rate capabilities at various rates with an average coulombic efficiency reaching 95.6%. It is obvious that TiO2 nanotube array possesses high rate capability and excellent cycling stability.

Amorphous and Crystalline TiO2 Nanotube Arrays for Enhanced Li-Ion Intercalation Properties

2011 ◽  
Vol 11 (4) ◽  
pp. 3641-3650 ◽  
Author(s):  
Dongsheng Guan ◽  
Chuan Cai ◽  
Ying Wang
Keyword(s):  
Nanotube Arrays ◽  
Li Ion ◽  
Ion Intercalation

scholarly journals Vertically Aligned Binder-Free TiO2 Nanotube Arrays Doped with Fe, S and Fe-S for Li-ion Batteries

2021 ◽  
Author(s):  
Suriyakumar Dasarathan ◽  
Mukarram Ali ◽  
Tai-Jong Jung ◽  
Junghwan Sung ◽  
Yoon-Cheol Ha ◽  
...  
Keyword(s):  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Kinetic Properties ◽  
Outer Diameter ◽  
Impregnation Method ◽  
Binder Free ◽  
Vertically Aligned ◽  
Inner Diameter ◽  
Current Densities ◽  
Discharge Capacities

Vertically aligned Fe, S, and Fe-S doped anatase TiO2 nanotube arrays are prepared by electrochemical anodization process using an organic electrolyte in which lactic acid is added as an additive. In the electrolyte, nanotube layers of greater length (12 μm) and high order with inner diameter of approx. 90 nm and outer diameter of approx. 170 nm are achieved. Doping of Fe, S, and Fe-S via simple wet impregnation method substituted Ti and O sites with Fe and S, which leads to enhance the rate performance at high discharge current densities. Discharge capacities of TiO2 tubes increased from 82 mAh g-1 (bare) to 165 mAh g-1 for Fe-S doped TiO2 at high current densities of 0.3 mAcm-2 after 100 cycles with exceptional capacity retention of 85% after 100 cycles. Owing to the enhancement of thermodynamic and kinetic properties by doping of Fe-S, Li-diffusion increas2ed resulting in remarkable discharge capacities of 143 mAh g-1 and 89 mAh g-1 at a current density of 7.4 mA cm-2 and 19 mA cm-2, respectively.

scholarly journals Morphological Changes in Lamellar Macular Holes According to SD-OCT Examination over a Long Observation Period

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1145
Author(s):  
Magdalena Kal ◽  
Izabela Chojnowska-Ćwiąkała ◽  
Mateusz Winiarczyk ◽  
Monika Jasielska ◽  
Jerzy Mackiewicz
Keyword(s):  
Retinal Thickness ◽  
Morphological Changes ◽  
Outer Diameter ◽  
Corrected Visual Acuity ◽  
Macular Holes ◽  
Kolmogorov Smirnov ◽  
Inner Diameter ◽  
Observation Period ◽  
Sd Oct

Background: The aim of this study was to evaluate the quantitative morphological changes in lamellar macular holes (LMHs) based on SD-OCT examinations and to assess the correlations among minimal retinal thickness (MRT), reading vision (RV), and best corrected visual acuity (BCVA) over a 36-month follow-up period. Methods: A group of 40 patients (44 eyes) with LMH was evaluated, with an average age of 69.87 (SD = 10.14). The quantitative parameters monitored in the follow-up period (at 0, 3, 6, 12, 18, 24, 30, and 36 months) were tested for normality of distribution by Shapiro–Wilk and Kolmogorov–Smirnov tests. Results: The RV and BCVA values were stable, and no significant changes were found at any of the check-ups during the 36-month follow-up period (BCVA p = 0.435 and RV p = 0.0999). The analysis of individual quantitative LMH parameters during the 36-month follow-up period did not demonstrate statistically significant differences: MRT (p = 0.461), Max RT temporal (p = 0.051), Max RT nasal (p = 0.364), inner diameter (ID) (p = 0.089), and outer diameter (OD) (p = 0.985). Conclusions: The observations at 0, 6, 12, 18, 24, 30, and 36 months revealed moderate and significant correlations between RV and MRT. No significant correlation between BCVA and MRT was observed.

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