NaFePO4 Cathode Prepared from The Caustic Fusion of A Mix Ilmenite-Hematite Followed by Cyclic Voltammetry for Na Insertion

Research to prepare NaFePO 4 cathode material from iron sand was conducted. The iron sand consists of ilmenite FeTiO 3 and hematite Fe 2 O 3 . A caustic fusion method used to precipitate iron as Fe(OH) 3 and it increased Fe content up to 94.71 %. Phosphate precipitation successfully produced trigonal FePO 4 and monoclinic FePO 4 comply with ICSD#412736 and ICSD#281079. The prepared-FePO 4 was then used as a precursor for Na insertion by applying cyclic voltammetry mode within 2.0 – 4.0 V with 0.05 mVs -1 of the scan rate. It produced orthorhombic olivine NaFePO 4 and a secondary phase of orthorhombic Na 0.7 FePO 4 . Impedance analysis at 20 Hz – 5 MHz found that the material provided a semicircle at 100 Hz peak point, indicating electrode-bulk interface with a resistance value of 1735W, comparable to the electrical conductivity of 5.36 x 10 -6 Scm -1 . Even though the conductivity value is quite lower than NaFePO 4 prepared from a commercial FePO 4 that has been conducted in our previous research, however the electrical conductivity still reliable for cathode.