Preparation of c-axis oriented thin films of LiCoO2 by pulsed laser deposition and their electrochemical properties
Preparation of c-axis oriented thin films of LiCoO2 by pulsed laser deposition and their electrochemical properties
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DOI：
10.1016/s0378-7753(00)00580-2
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发表时间：
2001-03-01
影响因子：
9.2
通讯作者：
Ogumi, Z
中科院分区：
文献类型：
--
作者：
Iriyama, Y;Inaba, M;Ogumi, Z
采用脉冲激光沉积法制备了c轴择优取向的LiCoO2薄膜。沉积1-2 h的薄膜具有择优的c轴取向，而沉积3 h及以上的薄膜则失去了择优取向。用电子显微镜和选区电子衍射仪对薄膜的织构进行了详细的分析。用循环伏安法和交流阻抗谱对薄膜的电化学性质进行了比较。在c轴取向薄膜的循环伏安图中，3.9V附近的一级相变对应的氧化峰和还原峰尖锐，且由于其薄而均匀的织构，峰间距较小。然而，它们的光滑表面和取向的(03)面的织构分别在垂直于衬底的方向上提供了较大的电荷转移阻力和较小的表观扩散系数，导致活性材料的利用率较低(接近50%)。在正极电压大于4.0V时，单相区的反应性低于无规取向薄膜。(C)2001 Elsevier Science B.V.保留所有权利。
Thin films of LiCoO2 with a preferred c-axis orientation were prepared by pulsed laser deposition. Thin films deposited for 1-2 h had a preferred c-axis orientation, but films deposited for 3h and longer lost the preferred orientation. The textures of these films were investigated in detail by transmission electron microscopy and selected area electron diffraction. The electrochemical properties of these films were compared by cyclic voltammetry and alternating current impedance spectroscopy. In the cyclic voltammograms of the c-axis oriented films, the anodic and cathodic peaks corresponding to the first-order phase transition at around 3.9 V were sharp and their peak separation was small due to their thin and uniform texture. However, their smooth surface and texture of the aligned (0 0 3) planes gave a larger charge-transfer resistance and a smaller apparent diffusion coefficient in the direction normal to the substrate, respectively, which resulted in poor utilizations (similar to 50%) of the active material. The reactivity in the single-phase region at potentials more positive than 4.0 V was lower than that of randomly oriented films. (C) 2001 Elsevier Science B.V. All rights reserved.