Synthesis Method of the Li-Ion Battery Cathode Material Li2FeSiO4 Using a Molten Carbonate Flux

A new synthesis method using molten carbonate flux was investigated in order to enhance the performance of the lithium ion battery cathode material Li 2 FeSiO 4 . The synthesis conditions of temperature, atmosphere, iron source and the amount of carbonate flux were examined. Fine powder with a mean particle size of about 1 μm and a phase purity of 99% Li 2 FeSiO 4 was obtained from iron and Li 2 SiO 3 using molten (Li 0.435 Na 0.315 K 0.25 ) 2 CO 3 flux under a CO 2 -H 2 atmosphere at 773 K. The Li 2 FeSiO 4 cathode showed discharge capacity of 162 mAh g −1 at the C/10 rate with good cyclability. Through the synthesis method, cathode material with good capacity and cyclability was obtained, utilizing low-cost iron powder at a lower temperature than that of the solid state reaction.