Electrochemical activity of nanocrystalline Fe3O4 in aprotic Li and Na salt electrolytes

Fe3O4 powders, whose average particle sizes were 400 nm, 100 nm, and 10 nm in diameter, were prepared in order to investigate the effect of particle size on their electrochemical activity. X-ray diffraction and electron microscopy measurements confirmed that all the prepared samples were identified as inverse-spinel type Fe3O4, whose crystallite/particle sizes were between 400 nm and 10 nm. We found that the electrochemical activity of Fe3O4 in a lithium salt electrolyte was enhanced with a decrease in the particle size from 400 nm to 10 nm. The 10 nm nanocrystalline Fe3O4 powder demonstrated the high discharge capacities of about 130 and 160 mAh g−1 with a satisfactory capacity retention as the active cathode material of Li and Na batteries, respectively.