R. Muruganantham

Investigations on the rate performance of LiFePO4/CeO2 composite materials via polyol technique for rechargeable lithium batteries

An attempt has been made to synthesize CeO2 modified LiFePO4 composite cathode materials via a polyol technique with a chemical combination route. The surface modified LiFePO4 samples exhibit superior electrochemical performances compared to bare samples. CeO2 may help to induce the fast lithium-ion diffusivity of LiFePO4 cathode materials to promote high-rate stable cycling and a good coulombic efficiency. The complete coverage of a mild coating of CeO2 under an optimized concentration on LiFePO4 may limit the direct contact of the active material with the electrolyte, which improves the interface stability by preventing the dissolution of Fe ions in the electrolyte.

Synthesis and electrochemical characterization of olivine-type lithium iron phosphate cathode materials via different techniques

High-potential, eco-friendly LiFePO4 cathode materials were synthesized by polyol, hydrothermal, and solid-state reaction methods. The polyol technique was carried out without any special atmosphere and postheat treatment. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectrometry (XPS), and charge-discharge and cyclic voltammetry tests. The LiFePO4 prepared via polyol technique exhibits good electrochemical performance than other method samples do.

Studies on graphene enfolded olivine composite electrode material via polyol technique for high rate performance lithium-ion batteries

The graphene enfolded LiFePO4/C composite cathode material has been prepared via low temperature polyol process, followed by a simple chemical reaction method. The low viscous polyol solvent (DEG) (35.7 mPa s at 25°C) and usage of low temperature process (below 245°C) aid the graphene tightly encapsulated on the LiFePO4 surface that plays an important role, especially in the high rate performances over long cycles, efficiently preventing the separation of the graphene and LiFePO4 during the reaction processes, hence realizing the full potential of the active materials. The graphitization on LiFePO4/C remarkably increased the electronic conductivity of LiFePO4. The layered sheets of graphene wrapped on LiFePO4 particles provide void between graphene sheets and LiFePO4 surfaces, which facilitate the diffusion of Li+. This approach opens up a method to attain the theoretical capacity of LiFePO4. The material exhibits a superior electrochemical performance such as initial discharge capacities of 169.6 and 92 mAhg−1 at 0.1 and 30 C rates, respectively. It has an excellent capacity retention and diminutive capacity fading. The nanosize of LiFePO4 particle causes a shorter diffusion path, which reduces the time for Li+ migration between cathode and electrolyte.

Studies on Chemical and Physical Properties of LiFeMPO 4 (M=Cu, La) by Polyol Route

Bare Lithium Iron Phosphate (LiFePO4), Cu, La doped and Cu with La co-doped LiFePO4 composite materials have been prepared via polyol technique without further post heat treatment. The prepared bare and composite materials’ crystalline structure has been indexed an orthorhombic phase olivine structure with space group of Pnma. The functional group vibrations and surface morphology of the prepared materials has been observed using Fourier transfer infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) with EDX analyses. Magnetization measurements revealed that saturation magnetizations (Ms) of the metal doped samples are gradually increased than that of the pure LiFePO4. All the samples exhibit the spin-glass behaviour of magnetic materials.

A Polyol Route LiFePO4 Cathode Material for Li-Batteries

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.