Modification of LiFePO_4 with Resorcinol-formaldehyde Resin as Carbon Source

Lithium ion battery cathode material LiFePO_4/C was prepared by using resorcinol- formaldehyde resin as carbon source.Effects of resin on purity and electrochemical performance of LiFePO_4 were investigated by XRD and galvanostatic charge-discharge test.The results indicate that the hydrogen resulted from pyrolysis of resorcinol-formaldehyde resin can react with LiFePO_4,then Fe_2P,FeP and Li_3PO_4 are formed.Such impurities will lead the capacity of the materials decrease. The impurities can be reduced significantly by carbonization at lower temperature before calcination at higher temperature.The capacity and cycle property of LiFePO_4 are improved greatly by the addition of resorcinol-formaldehyde resin.The specific discharge capacity of LiFePO_4 reaches up to 160,150,135 and 120mAh/g at 0.2C,1C,2C and 5C(1C=150mA/g) rates,respectively.