Synthesis of hollandite-type LixMnO2 by Li+ ion-exchange in molten salt and lithium insertion characteristics
Synthesis of hollandite-type LixMnO2 by Li+ ion-exchange in molten salt and lithium insertion characteristics
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DOI：
10.1016/j.electacta.2007.08.052
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发表时间：
2007-12
影响因子：
6.6
通讯作者：
Y. Kadoma;Satoru Oshitari;K. Ui;N. Kumagai
中科院分区：
文献类型：
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作者：
Y. Kadoma;Satoru Oshitari;K. Ui;N. Kumagai
在 300°C 的 LiNO3-LiCl 熔盐中研究了含有不同量水分子 (n=0–0.15) 且具有大 (2×2) 隧道结构的 K+ 型 α-K0.14MnO1.93·nH2O 的 Li+ 离子交换反应。通过化学分析、X射线衍射和透射电子显微镜测量来检查Li+离子交换产物。 α-MnO2的(2×2)孔道中的K+离子和水分子中的氢与熔盐中的Li+离子进行交换，得到在(2×2)孔道中含有不同量的Li+离子和氧化锂(Li2O)的Li+型α-MnO2，同时保持了原有的镁锰矿结构。在寻找可充电锂电池的新型正极材料时，作为插入化合物，研究了 Li+离子交换的 α-MnO2 样品的电化学性能和结构随初始放电和充放电循环的变化。 Li+离子交换的α-MnO2样品在初始放电和充放电循环中比母体K+型材料提供了更高的容量和更高的Li+离子扩散率，这可能是由于（2×2）隧道中Li2O的存在导致结构稳定。
The Li+ion-exchange reaction of K+-type α-K0.14MnO1.93·nH2O containing different amounts of water molecules (n=0–0.15) with a large (2×2) tunnel structure has been investigated in a LiNO3–LiCl molten salt at 300°C. The Li+ion-exchanged products were examined by chemical analysis, X-ray diffraction, and transmission electron microscopy measurements. The K+ions and the hydrogens of the water molecules in the (2×2) tunnels of α-MnO2were exchanged by Li+ions in the molten salt, resulting in the Li+-type α-MnO2containing different amounts of Li+ions and lithium oxide (Li2O) in the (2×2) tunnels with maintaining the original hollandite structure. The electrochemical properties and structural variation with initial discharge and charge–discharge cycling of the Li+ion-exchanged α-MnO2samples have been investigated as insertion compounds in the search for new cathode materials for rechargeable lithium batteries. The Li+ion-exchanged α-MnO2samples provided higher capacities and higher Li+ion diffusivity than the parent K+-type materials on initial discharge and charge–discharge cyclings, probably due to the structural stabilization with the existence of Li2O in the (2×2) tunnels.