Effect of Precipitator and Quantity on the Formation of Fe 3 (PO 4 ) 2

The effect of the precipitator (NaOH, ) and the amount of the precipitator (150, 200, 250, 300 ml) on the formation of , which is the precursor used for cathode material in Li-ion rechargeable batteries was investigated by the co-precipitation method. A pure precursor of olivine was successfully prepared with coprecipitation from an aqueous solution containing trivalent iron ions. The acid solution was prepared by mixing 150 ml (1M) and 100 ml (1M). The concentration of the NaOH and solution was 1 M. The reaction temperature (25) and reaction time (30 min) were fixed. Nitrogen gas (500 ml/min) was flowed during the reaction to prevent oxidation of . Single phase was formed when 150, 200, 250 and 300 ml NaOH solutions were added and 150, 200 ml solutions were added. However, and were formed when 250 and 300 ml was added. The morphology of the changed according to the pH. Plate-like lenticular shaped formed in the acidic solution below pH 5 and plate-like rhombus shaped formed around pH 9. For the , the pH value after 30 min reaction was higher with the same amount of additions of NaOH and . It is believed that the formation mechanism of is quite different between NaOH and . Further investigation on this mechanism is needed. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and the pH value was measured by pH-Meter.