Long-term cyclability of LiFePO4/carbon composite cathode material for lithium-ion battery applications

A simple high-energy ball milling combined with spray-drying method has been developed to synthesize LiFePO4/carbon composite. This material delivers an improved tap density of 1.3 g/cm3 and a high electronic conductivity of 10−2 to 10−3 S/cm. The electrochemical performance, which is especially notable for its high-rate performance, is excellent. The discharge capacities are as high as 109 mAh/g at the current density of 1100 mA/g (about 6.5C rate) and 94 mAh/g at the current density of 1900 mA/g (about 11C rate). At the high current density of 1700 mA/g (10C rate), it exhibits a long-term cyclability, retaining over 92% of its original discharge capacity beyond 2400 cycles. Therefore, the as-prepared LiFePO4/carbon composite cathode material is capable of such large-scale applications as hybrid and plug-in hybrid electric vehicles.