Synthesis and electrochemical properties of Na2/3Fe1/3Mn2/3O2 cathode materials for sodium ion battery by spray pyrolysis

Na2/3Fe1/3Mn2/3O2 precursor powders were successfully prepared by spray pyrolysis process. Na2/3Fe1/3Mn2/3O2 precursor powders were calcined from 700 to 1100 degrees C. The chemical and physical properties of Na2/3Fe1/3Mn2/3O2 precursor powders and the calcined powders were characterized by powder X-ray diffraction (XRD) and a scanning electron microscope (SEM). XRD revealed that the diffraction patterns of the calcined powders were in agreement with the layered structure. The crystal phases of the calcined powders obtained from 800 to 1100 degrees C were the phase of P2 structure (space group: P-63/mmc). Na2/3Fe1/3Mn2/3O2 precursor powders exhibited spherical morphology with 1 mu m and were nonaggregated. The morphology of Na2/3Fe1/3Mn2/3O2 precursor powders changed to irregularly morphology with 1.5 mu m by calcining at 900 degrees C. P2-Na2/3Fe1/3Mn2/3O2 cathode materials calcined at 900 degrees C exhibited high rechargeable capacity and cycle stability. The first discharge capacity of P2-Na2/3Fe1/3Mn2/3O2 cathode materials was approximately 150mAhg(-1) at a rate of 0.1 C. 93% of the initial discharge capacity was maintained after 20 cycles. (C) 2014 The Ceramic Society of Japan. All rights reserved.