不同氧压下脉冲激光沉积LiCoO2薄膜的研究

使用脉冲激光沉积(PLD)法,在不同的氧压下制备了锂离子二次电池正极材料LiCoO2的薄膜.利用X射线衍射(XRD)、原子力显微镜(AFM)等分析测试方法,对沉积的薄膜进行了晶体结构和表面形貌的分析.结果显示,氧压达到正常标准时(加Pa),LiCoO:薄膜具有明显的c轴择优取向,同时薄膜的晶粒尺寸更为均匀,表面更为光滑.而氧压较低(1 Pa)时,薄膜表现为随机取向.这些结果表明,PLD方法制备LiCoO2薄膜时应该充分考虑腔体气压对等离子体的散射作用以提高薄膜表面的质量.     

Ab initio studies on n-type and p-type Li4Ti5O12

This paper studies the structure and electronic properties of Li4Ti5O12, as anode material for lithium ion batteries, from first principles calculations. The results suggest that there are two kinds of unit cell of Li4Ti5O12: n-type and p-type. The two unit cells have different structures and electronic properties:the n-type with two 16d site Li ions is metallic by electron, while the p-type with three 16d Li ions is metallic by hole. However, the Li4Ti5O12 is an insulator. It is very interesting that one n-type cell and two p-type cells constitute one Li4Ti5O12 supercell which is insulating. The results show that the intercalation potential obtained with a p-type unit cell with one additional electron is quite close to the experimental value of 1.5 V.