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

Well-shaped spherical agglomerates of FePO_4 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 FePO_4 particles were investigated by experimental and theoretical analyses.The analyses revealed that amorphous FePO_4 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 FePO_4 particles,and smooth spherical FePO_4 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 LiFePO_4 and catalysts.