Synthesis of LiFePO4 Using FePO4 Produced by Electrolyzing Fe1.5P Waste Slag

Fe1.5P waste slag was galvanostatically electrolyzed without separator in a H3PO4 aqueous solution using graphite as the cathode, and the electrolyte color turned from achromatism to yellow after electrolysis. Light yellow powder was finally obtained by adjusting the value of pH using ammonia water, filtering, washing and drying in sequence. The results of XRD and TG-DTA showed that the as-electrolyzed product was FePO4 center dot 2H(2)O. The as-obtained FePO4 center dot 2H(2)O was mixed well with LiOH center dot H2O and glucose to form a rheological phase precursor by using ethanol as a dispersing agent. LiFePO4/C composite was synthesized successfully by calcining the above precursor at 700 degrees C in an Ar atmosphere. The electrolysis process was investigated via a potentiodynamic polarization method. The structure, morphology and electrochemical performance of the as-synthesized LiFePO4/C composite were characterized by XRD, SEM and cyclic voltammetry, respectively. There was no impurity indexed peaks from Fe1.5P raw material, and the oxidization potential and the reduction potential were at 3.54 V and 3.33 V, respectively. The good experimental results indicated that electrolysis of Fe1.5P waste slag using an anode bag can eliminate the effect of impurities from raw material and the polarization between lithium ion intercalation and de-intercalation was low.