Nanocrystalline magnetite: Synthetic crystallite size control and resulting magnetic and electrochemical properties

A synthetic strategy for magnetite (Fe₃O₄) crystallite size control is reported, along with the detailed characterization and electrochemical measurements of Fe₃O₄ samples of varying crystallite sizes. Nanocrystalline Fe₃O₄ is prepared by coprecipitation induced by triethylamine from aqueous iron(II) and iron(III) chloride solutions of varying concentrations. Variation of the iron(II) and iron(III) concentrations results in crystallite size control of the Fe₃O₄ products. Materials characterization of the Fe ₃O₄ samples is reported, including X-ray diffraction, transmission electron microscopy, particle size, and saturation magnetization results. A strong correlation between discharge capacity and voltage recovery behavior vs magnetite crystallite size was observed when tested as an electrode material in lithium electrochemical cells.