Spectroscopic and Electrochemical Properties of Lithium-Rich LiFePO₄ Cathode Synthesized by Solid-State Reaction

Lithium iron phosphate (Li_xFePO₄) is synthesized by a solid-state reaction method. The structural, electrical and electrochemical properties are studied in detail. It is found that the increment of lithium concentration (up to x = 1.05) does not affect the structure of LiFePO₄ but improves its electrical conductivity as well as electrochemical performance. Surface morphological studies exhibited the formation of rod-like nanoparticles with small size. Electric and dielectric properties are also investigated over a frequency range of 1 Hz–1 MHz at different temperatures. The conductivity increased with increasing temperature, which follows the Arrhenius relation with the activation energy of about 0.31 eV. And the electrochemical tests found that the Li_1.05FePO₄ cathode possessed improved discharge capacity with better cycling performance.