Electrochemical Properties of Sn-Substituted LiMn2O4 Thin Films Prepared by Radio-Frequency Magnetron Sputtering

Abstract

The LiMn2O4 and LiSn0.0125Mn1.975O4 thin films were grown on Pt/Ti/SiO2/Si (100) substrate by RF magnetron sputtering. To obtain the structural stability and good cycle performance, deposition parameters, namely working pressure, sputtering gas ratio of Ar and O-2, post-annealing temperature were established. The structure and surface morphology of thin films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemical properties were estimated by two electrode half-cell test with WBCS 3000 (Wonatech, Korea) at constant current rate of 1 C-rate. The Sn substituted LiMn2O4 thin film deposited at 10 mtorr with mixture of argon and oxygen (Ar/O-2 = 3/1) and then annealed at 500 degrees C in O-2 atmosphere showed good cycle performance. The Sn substituted LiMn2O4 thin films showed larger capacity of similar to 30 mu Ah/mu m-cm(2) and higher cyclability than LiMn2O4 thin films.