The Effect of Carbon Coating on the Electrochemical Performance of Nanosized $Li_2FeSiO_4$ Cathode Materials

Carbon-coated $Li_2FeSiO_4//C$ cathode materials have been synthesized through a modified ball-milling process. The physical characterizations of $Li_2FeSiO_4$ were conducted by using X-ray powder diffraction, field-emission scanning electron microscopy and transmission electron microscopy techniques. Field-emission scanning electron microscopy and transmission electron microscopy images revealed that $Li_2FeSiO_4//C$ consists of nanosized particles coated with an amorphous carbon layer. The electrochemical performances of $Li_2FeSiO_4//C$ cathode materials were evaluated through fully assembled lithium batteries via cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy. The $Li_2FeSiO_4//C$ cathode materials showed a much improved electrochemical performance in terms of higher specific capacity, better cycling performance and less charge transfer resistance than that of the pristine $Li_2FeSiO_4$.