摘要
以硝酸锂和硝酸锰为原料,尿素为燃料,用液相燃烧合成方法制备尖晶石型LiMn2O4物质,考察了焙烧温度(300-800℃)和焙烧时间(0-48h)对产物的组成结构和晶粒大小的影响.实验结果表明,未焙烧产物中主晶相为LiMn2O4,但含有大量Mn2O3;在300-800℃焙烧时,温度越高,所得尖晶石型LiMn2O4的纯度越高、晶粒越大、晶粒发育越完整,焙烧温度≤600℃时焙烧时间对提高产物中LiMn2O4的纯度影响不大,产物颗粒为纳米级,但焙烧温度大于700℃时影响较大,产物颗粒增大,产物中Mn2O3的含量随焙烧时间增加减少的幅度较大,制备LiMn2O4燃烧产物的最佳焙烧温度为800℃,保温6h左右.但焙烧温度为800℃焙烧时间大于8h时,LiMn2O4会分解生成Mn3O4.
Spinel LiMn2O4 powders were prepared by solution combustion synthesis using nitrate lithiumand manganese as raw materials, and urea as fuel. The effects of calcination temperatures （300-800℃） and calcination times （0-48h） on the phase composition and grain size of products were studied. The results indicated that the product that was not calcinated had the main phase of LiMn2O4, and a mount of impurity of Mn2O3. At the calcination temperature of 300-800 ℃, the purity of LiMn2O4 increased, the grain size en- larged, and the crystallization was better, with the increasing temperatures. The effect of calcination time on the products was inconspicuous below 600℃, and notable above 700℃. Scanning electron microscope （SEM） images showed that nanocrystalline LiMn2O4 was obtained when the calcination temperature was lower than 600℃ and the grain size increased at higher temperatures. Above 700℃, the content of Mn2O3 in products decreased with increasing calcination times. The optimum calcination temperature was 800℃ for 6h. At 800℃, if the calcination time was greater than 8h, LiMn2O4 would be decomposed to Mn3O4.
出处
《红河学院学报》
2008年第5期1-5,共5页
Journal of Honghe University
基金
国家自然科学基金重大研究计划面上项目(90610011)
云南省自然科学基金(2006E0091M)
