热处理过程对湿化学法合成锂锰氧化物结构的影响

采用湿化学法在常压及温度低于100℃的水溶液中，使锂盐与锰盐发生化学反应生成LiMn

Changes in the structure of spinel LiMn_2O_4 synthesized by wet chemical technique in the calcinating process

A LiMn2O4 compound was synthesized in aqueous solution from lithium compound which reacted with manganese compound by means of wet chemical technique at normal atmosphere and temperature of less than 100 ℃. After being filtered and washed with water, then dried at 105 ℃, the precursor of LiMn2O4 compound with an amorphous structure can be obtained. The changes in the crystal structure and the shape of LiMn2O4 samples with the calcinating temperature and time were detected by means of X-ray diffraction and scanning electron micrograph. The results show that perfect spinel LiMn2O4 crystals can be obtained from the precursor of LiMn2O4 after being calcinated. It is concluded that the calcinating temperature has great influences on the crystal structure of LiMn2O4. With the elevating of the temperature, the crystal structure becomes more perfect and the particle size gets larger. Only LiMn2O4 XRD patters can be observed when the sample is calcined at 500 ℃ and it is showed that the structure of LiMn2O4 compound is completely transformed from amorphous to spinel. A spinel type LiMn2O4 with regular crystal structure and well-distributed particle size can be obtained after being calcinated for 4 h at 700 ℃. However, it is also observed that the calcinating time has less effect on the perfection of the LiMn2O4 structure and the samples almost maintain the same XRD patterns when the calcinating time is prolonged at the same temperature.