Li-ion transport kinetics in LiMn2O4 thin films prepared by radio frequency magnetron sputtering

LiMn2O4 thin films were deposited on silica glass substrates by radio frequency (RF) magnetron sputtering. The films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Li-ion chemical diffusion coefficients D˜Li were measured by cyclic voltammetry (CV), potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS) and limiting current density (LCD). The D˜Li values depended on the content of Li in LixMn2O4. It was found that the D˜Li values by CV, PITT and LCD were in the order of 10−10, 10−11 and 10−12 cm2 s−1, respectively, and those by EIS were in the range of 10−9 to 10−11 cm2 s−1. The D˜Li values obtained by above methods were compared with those by an electron blocking method. It turned out that the D˜Li values by the electron blocking method were more comparable with those by EIS.