| Popis: |
LiFePO 4 has become of great interest as storage cathodes for rechargeable lithium batteries because of their high energy density, low raw materials cost, environmental friendliness, high thermal stability. In the present investigation, lithium iron phosphate ( LiFePO 4) cathode material has been prepared by using hydrothermal synthesis. The structure of the sample has been studies by using X-ray diffraction. The XRD spectrum exhibited different characteristic peaks along with (311) predominant orientation corresponding to an orthorhombic crystal structure with Pnma space group. Electrical and dielectric properties were studied over a frequency range of 1 Hz – 1 MHz at different temperatures. The electrical conductivity was found to be increased with increasing temperature following Arrhenius relation with an estimated activation energy of 0.44 eV. The dielectric properties were analyzed in the framework of complex dielectric permittivity and complex electric modulus formalisms. The evolution of the complex permittivity as a function of frequency and temperature was investigated. Several important parameters such as activation energy, ionic hopping frequency, carrier concentration, ionic mobility and diffusion coefficient etc, were determined. |
