Synthesis of spherical spinel LiMn2O4 with commercial manganese carbonate

Spherical spinel LiMn2O4 particles were successfully synthesized from a mixture of manganese compounds containing commercial manganese carbonate by sintering of the spray-dried precursor. Different preparation routes were investigated to improve the tap density and to enhance the electrochemical performance of LiMn2O4. The structure and morphology of the LiMn2O4 particles were confirmed by X-ray diffraction (XRD) and scanning electron microscopy. The results showed that hollow spherical LiMn2O4 particles could be obtained when only commercial MnCO3 was used as the manganese source. These particles had a low tap density (ca.0.8 g/cm3). Perfect micron-sized spherical LiMn2O4 particles with good electrochemical performance were obtained by spray-drying a slurry composed of MnCO3, Mn(CH3CHOO)2 and LiOH, followed by a dynamic sintering process and a stationary sintering process. The as-prepared spherical LiMn2O4 particles comprised hundreds of nanosize crystal grains and had a high tap density(ca. 1.4 g/cm3). The galvanostatic charge–discharge measurements indicated that the spherical LiMn2O4 particles had an initial capacity of 121 mAh/g between 3.0 and 4.2 V at 0.2 C rate and still delivered a reversible capacity of 112 mAh/g at 2 C rate. The retention of capacity after 50 cycles was still 96% of its initial capacity at 0.2 C. All the results showed that the as-prepared spherical LiMn2O4 particles had an excellent electrochemical performances. The methods we used for preparing spherical LiMn2O4 are energy-saving and suitable for industrial application.

Graphical AbstractPerfect spherical LiMn2O4 particles with high tap density and good electrochemical performance were successfully synthesized from commercial manganese carbonate. The optimized processes consisted of spray-drying a slurry composed of MnCO3, Mn(CH3CHOO)2 and LiOH, followed by a low-temperature dynamic sintering process and a high-temperature stationary sintering process. The methods used are energy-saving and suitable for industrial application.Figure optionsDownload as PowerPoint slideResearch Highlights
► Spherical LiMn2O4 particles were successfully synthesized with commercial MnCO3.
► Spherical LiMn2O4 has high tap density and good electrochemical performance.
► LiMn2O4 particles were shaped by a spray-drying process.
► Dynamic sintering process and stationary sintering process were combined.
► The method is an improved energy-saving process.