A new and fast synthesis of nanosized LiFePO4 electrode materials

LiFePO4 has been prepared as highly crystalline nanoparticles (approx. 80 mn in diameter) of well-defined shape by heating a mixture containing lithium acetylacetonate, iron oxalate, ammonium hydrogen phosphate and oxalic acid under argon at 550 degrees C for 2 h. The resulting solid contains about 6% magnetite (Fe3O4) as an impurity. Despite its small particle size, this nanomaterial exhibits relatively poor electrochemical performance in lithium cells owing to its lack of electronic conductivity. Its electrochemical response contrasts with previously reported data for nano-LiFePO4 materials prepared at such low temperatures. In order to overcome its lack of conductivity, the compound was treated with a copper precursor. The copper phosphate nanocomposite thus obtained exhibits improved electrochemical performance in terms of capacity and cycling life in lithium cells. Thus Cu-LiFePO4-based cells deliver capacity values close to 80 mAhg(-1) over at least 50 cycles under a C/10 regime. These values testify to the usefulness of the proposed synthetic method for preparing nanoparticulated lithium phosphate-based electrodes. (c) Wiley-VCH Verlag GmbH & Co.