Preparation of Spherical FePO4 by Chemical Co-precipitation Combined with Spray-Drying

Abstract

Well-shaped spherical agglomerates of FePO4 particles were prepared by a novel method: chemical co-precipitation combined with spray-drying. Tap density analysis, Brunauer–Emmett–Teller analysis, characterizations of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy confirmed that the micron-sized spherical agglomerates with high specific surface area and high tap density were composed of the uniform nano-sized particles. The effects of pH and reaction time on the morphology of the FePO4 particles were investigated by experimental and theoretical analyses. The analyses revealed that amorphous FePO4 was responsible for forming a well-shaped spherical agglomerate, and the ideal spherical particles were obtained at pH 3. The reaction time also played a significant role in controlling the size and surface morphology of the FePO4 particles, and smooth spherical FePO4 particles were obtained at a reaction time of 6 h. By this novel method, poly-porous spherical iron phosphate particles were prepared, which can be used with high efficiency in some special fields, especially as a precursor for synthesizing LiFePO4 and catalysts.