Dynamic sintering Lithium ion battery
Spherical spinel LiMn 2 O 4 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 LiMn 2 O 4 . The structure and morphology of the LiMn 2 O 4 particles were confirmed by X-ray diffraction (XRD) and scanning electron microscopy. The results showed that hollow spherical LiMn 2 O 4 particles could be obtained when only commercial MnCO 3 was used as the manganese source. These particles had a low tap density (ca.0.8 g/cm 3 ). Perfect micron-sized spherical LiMn 2 O 4 particles with good electrochemical performance were obtained by spray-drying a slurry composed of MnCO 3 , Mn(CH 3 CHOO) 2 and LiOH, followed by a dynamic sintering process and a stationary sintering process. The as-prepared spherical LiMn 2 O 4 particles comprised hundreds of nanosize crystal grains and had a high tap density(ca. 1.4 g/cm 3 ). The galvanostatic charge-discharge measurements indicated that the spherical LiMn 2 O 4 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 LiMn 2 O 4 particles had an excellent electrochemical performances. The methods we used for preparing spherical LiMn 2 O 4 are energy-saving and suitable for industrial application.