采用溶液沉积及快速退火制备了不同厚度的LiMn2O4薄膜,用X射线衍射及扫描电子显微镜检测分析薄膜的物相及形貌;采用恒电流充放电及交流阻抗技术研究了LiMn2O4薄膜的电化学性质。结果表明,制备的LiMn2O4薄膜均匀,晶粒大小相近,晶粒尺寸在20~50 nm之间。经热处理后LiMn2O4薄膜断面清晰,薄膜与基片之间扩散很轻微。随着薄膜厚度的增加,薄膜的粗糙度减小,平整度变好。不同厚度的LiMn2O4薄膜的比容量介于42~47μAh/(cm2.μm)之间,经50次循环后,薄膜的容量损失率从0.18μm的0.64%上升到1.04μm的9.0%,循环性能随着薄膜厚度的增加而变差。电化学阻抗测试表明不同厚度的LiMn2O4薄膜锂离子扩散系数差别不大,数量级为10-11cm2/s。
LiMn2O4 thin films of different thickness were prepared by solution deposition and rapid thermal annealing.The phase identification and surface morphology were studied by X-ray diffraction and scanning electron microscopy.The electrochemical properties of thin films were carried out by galvanostatic charge-discharge experiments and electrochemical impedance spectroscopy.The films of different thickness are homogeneous with the grain size between 20-50 nm.The cross section of the film is very clear.The film ...