Octadecylamine oxide as the template synthesis of lithiated vanadium oxides half opened- nanotubes first love mp3
Synthesis of Lithiated Vanadium Oxides Half Opened- nanotubes as CathodeMaterials for Lithium Ion Batteries
Junli Sun*
Institute of Science and Rearch, Department of Science and Rearch, Chine People’s Armed Police Force Academy, 220 Xihuan Road, Anci District, Langfang City, Hebei Province (065000), China. Tel (86)316-2067617
Abstract
The lithiated vanadium oxides half opened- nanotubes (HOT) are synthesized by using solid-state and solvothermal reaction with octadecylamine oxide as the template. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) characterizations show that the synthesized lithiated vanadium oxidesjusco nanotubes are half o
pened and agglomerate. X-ray diffraction (XRD) investigation demonstrates that the synthesized half opened-nanotubes are most consisted of monoclinic pha LiV3O8. Cyclic voltammetry (CV) test indicates that some redox process are hindered, which is propitious to improve electrochemical performance of LiV3O8 cathode material.
Keywords: electrochemical properties; nano structures; SEM; TEM
Introduction 如何用牛奶洗脸
Nanostructured cathode and anode materials in lithium ion batteries have attracted great attention. This is becau they show higher capacity than conventional
*Corresponding author. Tel.: +86-316-2067617; Fax: +86-316-2067613
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electrodes compod of the same materials, and the surface area of nanostructured elect
rodes is much larger than that of conventional electrodes. Vanadium oxides have been widely studied as cathode active materials in lithium rechargeable batteries becau of their low cost and high theory capacity [1-6]. Chen W et al. u the template hydrothermal treatment to synthesize V2O5 nanotubes. When they are ud as cathode, the resulting cell has shown initial discharge specific capacity of 306mAh g-1 at 3.6-1.5V, which is significantly superior to that of materials prepared by conventional methods. This nanotube can maintain 80% of its initial capacity [7]. But there were no reports about any methods to process LiV3O8 half opened-nanotubes electrode material. In this work, high-ordered LiV3O8 half opened- nanotubes arrays are synthesized by using The solid-state and solvothermal reaction with octadecylamine oxide as the template.
Octadecylamine (18胺)
Cetyltrimethylammonium bromide(CTAB)
2 Experimental
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All of the chemical reagents were of analytical grade and ud without further purification. 1. V2O5 (0.06 mol) was added to 25 ml 30% (w/w) H2英语语感O2 aqueous solution, and the resulting mixture was stirred for 2 h. Then, 0.04 mol mixtures (LiOH·H2O and AgNO3 with different mol ratios) 一对一托福辅导were added in submarinea desired stoichiometric ratio, together with 15 ml of 1 mol/L HNO3 aqueous solution. 英语演讲mp3PH measurement is performed with a pH meter using 2.4 for calibration.
After continuous stirring for 2 hours, the resulting precursor suspension was transferred into a 100 mL Teflon-lined autoclave and maintained at 180 °C for a certain time. After being cooled to ambient temperature naturally, the solution in the autoclave was collected and finally vacuum-dried at 100英语培训那个机构好 °C for 12 h. Finally the solid powder was calcined at certain temperatures for 16 hours. For comparison, without hydrothermal route, LiV3O8 particles were also calcined at 400 °C for 16 hours.
2.2. Measurements
The composite cathodes (mg/cm2) were prepared by pressing the mixture of the active m
aterials, conductive material (acetylene black) and binder (PTFE) in a weight ratio of 8/1/ 1. The Li metal was ud as the counter and reference electrodes. The electrolyte was 1 M LiPF6 in a 6/3/1 (volume ratio) mixture of ethylene carbonate (EC), propylene carbonate (PC) and dimethyl carbonate (DMC). The galvanostatic method was employed to measure the electrochemical capacity of the samples at a current density of 60mAg-1, with the same cut-off voltages (1.8-4.0 V) for charge and discharge process, respectively. All tests were performed at room temperature
sonX-ray powder diffraction (XRD) was carried out using XRD (D/Max-2500). Scanning Electron Microscopy (SEM) measurements were carried out on a Hitachi S-570 microscope. CHI 660b electrochemical workstation was ud to test Cyclic voltammetry (CV) (scan rate: 0.1 mVs−1, cut off voltage: 1.8–4.0 V) measurements.
