A novel route for FePO4 olivine synthesis from sarcopside oxidation.

Heterosite FePO 4 is synthesized for the first time by direct thermal oxidation of sarcopside Fe 3 (PO 4 ) 2 . Both FePO 4 and Fe 3 (PO 4 ) 2 have a pseudo olivine structure. Complete isostructural conversion of sarcopside into FePO 4 is achieved at a temperature of 450 °C within 3 days according to the reaction Fe 3 (PO 4 ) 2 + ¾ O 2 → 2 FePO 4 + ½ Fe 2 O 3 which leads to the extraction of iron from the sarcopside structure. Appropriate heating ramp must be applied in order to avoid the crystallization of Fe 7 (PO 4 ) 6 . Electrochemical performances of the oxidation product are consistent with those of olivine FePO 4 . [ABSTRACT FROM AUTHOR]