自混合熔盐燃烧合成LiMn_2O_4的初步研究

A Preliminary Study of the Eutectic Self-Mixing Molten-Salt Combustion Synthesis of LiMn_2O_4

以低熔点醋酸锂(70℃)和醋酸锰(80℃)为原料,在不添加任何燃料的条件下,用熔盐燃烧合成法制备尖晶石型LiMn2O4正极材料.研究了600℃点燃温度下,不同保温时间以及2次焙烧的工艺条件对产物的影响.结果表明,在600℃通过延长保温时间不能得到单相尖晶石型LiMn2O4产物,只能得到主晶相为尖晶石型LiMn2O4的产物.保温时间1 h时产物中有Mn3O4和Mn2O3 2种杂质,而保温时间达3 h及以上时,产物中只有Mn2O3杂质,其中以保温时间6 h得到的LiMn2O4含量最高,杂质最少;产物经600℃2次焙烧12 h后可得到单相尖晶石型LiMn2O4物质,且增加焙烧时间大于12 h后对样品中成分基本无影响;产物中LiMn2O4的结晶性随焙烧时间增加而逐渐增加.

Spinel LiMnzO4 for the cathode material of lithium ion batteries was prepared by molten -salt combustion synthesis, using eutectic point materials lithium acetate （70℃ ） and manganese acetate （80 ℃ ） as starting materials without any fuels. The effect of calcining time and second calcination at 600 ℃ on the products was studied. The results indicated that single phase LiMn2O4 could not be synthesized through extension of calcining time at 600 ℃ but the product with the main phase of LiMn2O4 could be synthesized. There were two impurities Mn3O4 and Mn2O3 in the product calcined at 600 ℃ for 1 h. There was only one impurity Mn2O3 in the product calcined at 600 ℃ for more than 3h, and the product with the highest content of LiMn2O4 and the lowest content of impurity was obtained at 600 ℃ for 6 h. Single phase LiMn2O4 was obtained after second calcination at 600 ℃ for 12 h, and the composition of products calcined more than 12 h changed little. The crystallinity of LiMn2O4 increased with the increasing calcining time.