Electrical and electrochemical properties of nanocrystalline LiFePO4 cathode

Lithium iron phosphate (LiFePO₄) cathode material has been prepared by hydrothermal synthesis. The XRD spectrum exhibited different characteristic peaks along with (311) predominant orientation corresponding to orthorhombic crystal structure with Pnma space group. Electric and dielectric properties were studied over a frequency range of 1 Hz–1 MHz at different temperatures. The 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 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. The electrochemical characteristics of LiFePO₄ are examined in aqueous region. It exhibited a good reversible cyclic voltammogram on sweeping the potential upward and downward with discharge capacity of 140 mAh/g.