Lithium Ion Battery Anode of Mesocrystalline CoTiO3/TiO2 Nanocomposite with Extremely Enhanced Capacity
Lithium Ion Battery Anode of Mesocrystalline CoTiO3/TiO2 Nanocomposite with Extremely Enhanced Capacity
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DOI：
10.1021/acsaem.1c02337
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发表时间：
2021-11
影响因子：
6.4
通讯作者：
Xing Wang;Weijie Cheng;Jiaqiao Hu;Ying Su;Xingang Kong;Shinobi Uemura;T. Kusunose;Q. Feng
中科院分区：
文献类型：
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作者：
Xing Wang;Weijie Cheng;Jiaqiao Hu;Ying Su;Xingang Kong;Shinobi Uemura;T. Kusunose;Q. Feng
介晶材料由具有相同晶体学取向的亚单元排列组成，作为锂离子电池（LIB）电极的活性材料具有潜在的应用。本文以层状钛酸H1.07Ti1.73O4（HTO）为前驱体，采用局部化学法合成了介晶CoTiO 3/TiO 2纳米复合材料。HTO的H2 O2处理导致更多的Co 2+通过H+/Co 2+交换反应嵌入层间，并通过HTO层和Co（OH）2-xx+层的堆叠形成三明治层状结构。通过在600 °C以上的热处理，这种三明治层状结构被拓扑转变为介晶CoTiO 3/TiO 2纳米复合材料。选区电子衍射结果表明，CoTiO 3/TiO 2纳米复合材料由[010]取向的CoTiO 3纳米晶和[110]取向的金红石TiO 2纳米晶构成。电化学测试结果表明，介晶CoTiO 3/TiO 2纳米复合材料具有极高的锂离子电池阳极容量，约为400 mAh/g，是多晶CoTiO 3的2倍。优异的阳极性能归因于介晶纳米复合材料中Li+的高迁移率以及纳米复合材料中TiO 2纳米晶的协同作用，提高了循环稳定性和电子电导率。
Mesocrystalline materials consisting of nanocrystal subunit alignment with the same crystallographic orientation have a potential application as active materials for lithium ion battery (LIB) electrodes. In this study, a topochemical process was developed to synthesize mesocrystalline CoTiO3/TiO2nanocomposites using a layered titanic acid H1.07Ti1.73O4(HTO) precursor. The H2O2treatment of HTO caused more Co2+intercalation into the interlayer by the H+/Co2+exchange reaction and the formation of a sandwich layered structure by stacking an HTO layer and a Co(OH)2–xx+layer. This sandwich layered structure was topotactically transformed into a mesocrystalline CoTiO3/TiO2nanocomposite by heat treatment at >600 °C. The selected area electron diffraction result suggests that the CoTiO3/TiO2nanocomposite is constructed from [010]-oriented CoTiO3nanocrystals and [110]-oriented rutile TiO2nanocrystals. The electrochemical results indicate that the mesocrystalline CoTiO3/TiO2nanocomposite exhibits an extremely enhanced anode capacity of about 400 mAh/g for LIB, which is 2 times higher than that of polycrystalline CoTiO3. The excellent anode performance can be ascribed to the high mobility of Li+in the mesocrystalline nanocomposite and the synergistic effect of TiO2nanocrystals in the nanocomposite by enhancing the cycling stability and electron conductivity.