Crystallization mechanism of sol‐gel synthesized spinel LiMn2O4
Crystallization mechanism of sol‐gel synthesized spinel LiMn2O4
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DOI：
10.1002/pssc.201400289
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发表时间：
2015-06
期刊：
影响因子：
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通讯作者：
K. Kushida;K. Kuriyama
中科院分区：
文献类型：
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作者：
K. Kushida;K. Kuriyama
采用差示扫描量热法（DSC）研究了溶胶-凝胶法合成尖晶石型LiMn 2 O 4的晶化机理。将乙酸锂和乙酸锰以1：2（Li：Mn）的原子比溶解在甲醇中，柠檬酸作为螯合剂，得到溶胶溶液。通过部分蒸发溶胶溶液获得Li-Mn凝胶前驱体。Li-Mn凝胶在280 °C时开始大的放热反应，表明从凝胶中释放的C和H原子的燃烧发生在280 °C以上。在温度上升到290 °C之后，凝胶的放热反应在290 °C的恒温下继续，表明用于结晶成尖晶石结构的Li、Mn和O原子的重排主要发生在290 °C。这表明在高于290 °C下退火Li-Mn凝胶前体对于获得尖晶石LiMn 2 O 4是必要的。在放热反应过程中，从凝胶中释放的Mn原子占据了尖晶石骨架中的八面体位置，并且也释放的Li原子插入到四面体位置。（© 2015 WILEY-VCH Verlag GmbH & Co. KGaA，魏因海姆）
Crystallization mechanism of sol-gel synthesized spinel LiMn2O4 is studied by a differential scanning calorimetry (DSC) method. Lithium acetate and manganese acetate are dissolved in methanol in the atomic ratio of 1:2 (Li:Mn) with citric acid as a chelating agent, leading to a sol solution. A Li-Mn gel precursor is obtained by partly evaporating the sol solution. A large exothermic reaction of the Li-Mn gel starts at 280 °C, indicating that the combustions of C and H atoms released from the gel occur above 280 °C. After the rise in temperature to 290 °C, the exothermic reaction of the gel continues at the constant temperature of 290 °C, indicating that the rearrangement of Li, Mn and O atoms for the crystallization into the spinel structure mainly occurs at 290 °C. This suggests that annealing the Li-Mn gel precursor above 290 °C is necessary to obtain spinel LiMn2O4. During the exothermic reaction, Mn atoms released from the gel occupy the octahedral sites in the spinel framework of O, and Li atoms also released are inserted into the tetrahedral sites. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)