Mn-doped NaFeO2from a low purity-Fe precursor and its performance as cathode for Sodium-Ion Battery

Research to produce Mn-doped NaFeO(2)was conducted from a low purity Fe-precursor aims to check the reliability for the inexpensive-mass production of the compound. The NaFeO(2)was prepared through the co-precipitation method from iron sand concentrate with Fe content of 86.72% consist of the hematite-ilmenite mixture. The reaction was conducted at 650 degrees C for 12 h under air argon atmosphere producing a mix of beta-NaFeO(2)and alpha-NaFeO2, which was then mixed with Mn(2)O(3)to produce Na1-x[Fe1-xMnx]O2-delta(NFMO) at various x of 0.02; 0.05; and 0.07. The result shows that Mn doping changed the crystal structure from orthorhombic into a hexagonal,P63/mmc. FTIR spectra provides peaks attributed to Na-O, Na-Fe, Mn-O, and Fe-O. Voltammetry analysis to NFMO-0.02 and NFMO-0.05 provide peaks attributed to Na+/Na and Fe3+/Fe(4+)redox reaction. Meanwhile, the NFMO-0.07 provides Na+/Na, Fe3+/Fe4+, and Mn3+/Mn2+. The NFMO-0.07 also shows the highest electrical conductivity of 1.372 x 10(-4)Scm(-1). A split cell test developed with NFMO-0.07 as cathode produced an initial specific capacity of 50.57 mAhg(-1)and an initial discharge capacity of 36.29 mAhg(-1)correlate to 71.70% Columbic efficiency.