Synthesis of LiFePO₄/C Nanocomposite and its Electrochemical Properties

LiFePO₄/C nanocomposite was synthesized by the polyol process without any further heating as a post step and its properties were compared to LiFePO₄ with no carbon. The X-ray diffraction patterns of all samples were indexed on the basis of the orthorhombic olivine-type structure. The field emission-SEM and TEM images of the nanocomposite showed agglomerated larger particles with rod type mixed with carbon nanoparticles. The initial discharge capacity of LiFePO₄/C nanocomposite showed 166 mAh/g at a current density of 0.1 mA/cm² in the voltage range of 2.5-4.2 V without capacity fading during the 20 cycles. Furthermore, the nanocomposite appeared more enhanced high rate performance, compared with the result of LiFePO₄ with no carbon, due to the existence of conductive agents such as carbon which suppresses particle growth and exhibits improved electronic conductivity and lithium ion diffusivity, simultaneously.