Preparation of LiFePO₄/C Composite Powders

Abstract

LiFePO 4 /C composite powders were prepared by a simple reaction of as-synthesized FePO 4 •2H 2 O, LiOH•H 2 O, oxalic acid and citric acid. The influence of oxalic acid and citric acid in different ratios was investigated on morphology and electrochemical performance of LiFePO 4 /C composite powders. The characterization of the composites included X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis indicates that the material is well crystallized without impurities. The obtained LiFePO 4 /C composite powders with well dispersion at CA/OA ratio of 1:1.50 and the initial charge capacity reached 159.3 mAhg -1 at 0.1C rate, meanwhile, the particles prepared at 1:0.75 were close to spherical in shape and the specific capacity value was 149.8 mAhg -1 at 0.1C rate, with a slight decrease on greater C-rates reaching 141.3 mAhg -1 at 1C.