Papers by Keyword: Lithium Rechargeable Battery

Abstract: Lithium ion battery technology has played a key role in portable electronics revolution, and it is vigorously pursued for electric vehicle applications. LiFePO4 has recently received a great deal of attention due to its potential usage as a next-generation cathode material for lithium-ion batteries such as power tools, electric vehicles (EVs)and hybrid electric vehicles (HEVs),etc.LiFePO4 is advantageous when comparing other conventional cathode materials such as LiCoO2, LiNiO2 and LiMn2O4, namely, it is inexpensive, environmentally benign and thermally stable, etc.. In the present work, LiFePO4 has been prepared using polyol method and its crystal structure has been confirmed by powder X-ray diffraction. The as-prepared LiFePO4 has olivine structure with space group Pnma and orthorhombic lattice parameters are calculated as a=10.3999Å, b=6.0070Å and c=4.6388Å. The functional group vibrations have been analyzed using Fourier Transform Infrared Spectroscopy (FT-IR). The surface morphology of synthesized material have been studied by scanning electron microscopy (SEM) and the compositional analysis were also been carried out through EDX analysis.

Abstract: Effects of substrate temperature and phosphor doping on electrochemical characteristics of the silicon film anode were investigated. The silicon thin films were synthesized directly on copper foil by radio-frequency capacitively coupled plasma-enhanced chemical-vapor deposition (r.f.-CVD). The cyclability of the silicon anode greatly depends on the surface morphology and surface resistivity. The silicon film anodes which have granular structure and high conductivity showed higher cyclabilty than those of planer and low conductivity, respectively.

Abstract: The synthesis and electrochemical characteristics of LiNi1-xCoxO2 (0 £ x £ 0.5) used as the promising cathode materials for lithium rechargeable batteries were investigated. The LiNi1-xCoxO2 was prepared by a soft chemistry route in which citric acid was used as the chelating agent to make the sol-gel precursor, then was calcined in oxygen atmosphere at the calcination temperature of 800°C for 12 h. Polycrystalline LiNi1-xCoxO2 possesses a hexagonal lattice of the α-NaFeO2 type characterized by using X-ray diffraction. The discharge capacity of LiNi0.8Co0.2O2 was 169.1 mAh/g with the efficiency of 90.5% in the first cycle and 162.1 mAh/g with only 4% capacity fading in the 10th cycle at 0.2 C rate over a potential range of 3.0-4.2 V.

Abstract: The charge/discharge properties of V2O5/carbon composites with controlled microstructures were investigated to achieve a high-rate lithium electrode performance. Composite electrodes were synthesized by mixing a V2O5 sol, carbon and a surfactant, followed by drying. V2O5/AB (acetylene black) and V2O5/VGCF (vapor-grown carbon fiber) composite electrodes showed high-rate charge/discharge properties only when they had very high carbon contents. V2O5/ (AB and VGCF) composite electrodes with controlled microstructures exhibited a discharge capacity of 245 mA·h·g-1 at a high current density of 40 A·g-1, which was approximately 70% of that at a low current density of 100 mA·g-1. The improvement in the high-rate charge/discharge properties was attributed to the short lithium ion diffusion distance, large reaction area and high electronic conductivity of those composite electrodes.