Synthesis of hollandite-type LiyMn1-xCoxO2 (x = 0-0.15) by Li+ ion-exchange in molten salt and the electrochemical property for rechargeable lithium battery electrodes
Synthesis of hollandite-type LiyMn1-xCoxO2 (x = 0-0.15) by Li+ ion-exchange in molten salt and the electrochemical property for rechargeable lithium battery electrodes
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DOI：
10.1016/j.jpowsour.2007.06.221
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发表时间：
2007-12
影响因子：
9.2
通讯作者：
N. Kumagai;Satoru Oshitari;S. Komaba;Y. Kadoma
中科院分区：
文献类型：
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作者：
N. Kumagai;Satoru Oshitari;S. Komaba;Y. Kadoma
研究了K+型α-K0.14 mno1.93·0.18H2O及其共掺杂α-K0.14(Mn0.85Co0.15)O1.96·0.21H2O具有大（2×2）隧道结构的Li+离子在LiNO3/LiCl熔盐中300℃的交换反应。采用化学分析、x射线衍射、扫描电镜和透射电镜等方法对Li+离子交换产物进行了表征。α- mno2及其共掺杂物（2×2）隧道中几乎所有的K+离子和水分子中的氢都被熔盐中的Li+离子交换，使得（2×2）隧道中的Li+型α- mno2及其共掺杂物中含有Li+离子和Li2O（氧化锂），同时保持了原有的荷兰石结构。研究了Li+离子交换α- mno2及其共掺杂样品作为插入化合物的充放电循环电化学性能，以期寻找新的可充电锂电池正极材料。Li+离子交换α- mno2及其共掺杂样品在初始放电和充放电循环中比K+型母材具有更高的容量，这可能是由于（2×2）隧道中Li2O的存在使结构稳定所致。
The Li+ion-exchange reaction of K+-type α-K0.14MnO1.93·0.18H2O and its Co-doped α-K0.14(Mn0.85Co0.15)O1.96·0.21H2O 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 scanning and transmission electron microscopic measurements. Almost all the K+ions and the hydrogens of water molecules in the (2×2) tunnel of α-MnO2and its Co-doped one were exchanged by Li+ions in the molten salt, resulting in Li+-type α-MnO2and its Co-doped one containing Li+ions as well as Li2O (lithium oxide) in the (2×2) tunnel with maintaining the original hollandite structure. The electrochemical properties including charge–discharge cycling of the Li+ion-exchanged α-MnO2and its Co-doped samples have been investigated as insertion compounds in the search for new cathode materials for rechargeable lithium batteries. The Li+ion-exchanged α-MnO2and its Co-doped samples provided higher capacities than the K+-type parent materials on initial discharge and charge–discharge cyclings, probably due to the structural stabilization with the existence of Li2O in the (2×2) tunnels.