Synthesis and characterization of three-dimensional carbon foams-LiFePO4 composites

The characterization of three-dimensional (3D) carbon foams coated with olivine structured lithium iron phosphate is reported for the first time. The LiFePO4 as cathode material for lithium ion batteries was prepared by a Pechini-assisted reversed polyol process. The coating has been successfully performed on commercially available 3D-carbon foams by soaking in aqueous solution containing lithium, iron salts and phosphates at 70 degrees C for 2-4 h. After drying-out, the composites were annealed at different temperatures in the range 600-700 degrees C for 15-20 min under nitrogen. The formation of the olivine-like structured LiFePO4 was confirmed by X-ray diffraction analysis performed on the powder prepared under similar conditions. The surface investigation of the prepared composites showed the formation of a homogeneous coating by LiFePO4 on the foams. The cyclic voltammetry curves of the composites show an enhancement of electrode reaction reversibility by decreasing the annealing temperature. The electrochemical measurements on the composites showed good performances delivering a discharge specific capacity of 85 mAh g(-1) at a discharging rate of C/25 at room temperature. (C) 2010 Elsevier B.V. All rights reserved.