Synthesis of microcrystalline LiFePO4 in air

• A method for the production of nano-sized microcrystalline LiFePO4 is proposed.
• The method is based on the solid state reaction of FePO4 with lithium acetate.
• This reaction may be carried out in air for 30 min at 550 °C.
• The LiFePO4 specific capacity was 170 mAh g− 1 at C/10 rate and 80 mAh g− 1 at 5C.

In this paper a method for the synthesis of nano-sized microcrystalline LiFePO4, which is particularly suitable for the production of high energy density electrodes, was developed. The method is characterized by the fact that it provides for the solid state reaction of anhydrous FePO4 with lithium acetate. The method is easy to implement and, above all, does not involve the need to operate in a controlled environment, since the material may be synthesized directly in air by mixing anhydrous FePO4 with lithium acetate. This latter is simultaneously used as a reducing and lithiating agent. Anhydrous FePO4 is prepared by dehydrating iron phosphate hydrate, which is in turn prepared by means of the spontaneous precipitation thereof from a solution of FeSO4 and NaH2PO4, using H2O2 as the oxidizing agent. The FePO4 used as the precursor is characterized by thermogravimetry and its morphology is investigated by SEM microscopy. The structure of LiFePO4 is characterized by X-Ray diffraction and its morphology investigated by SEM microscopy. Finally, the LiFePO4 is used to fabricate composite electrodes that are electrochemical tested in lithium cells.