Investigation of deposition condition of LiMn₂O₄ films prepared by RF magnetron sputtering

Abstract

The LiMn 2 O 4 films for Li secondary batteries have been prepared by a RF magnetron sputtering method. This research was designed for investigating the deposition condition of the films. The parameters were sputtering time, RF power, sputtering pressure and sputtering atmosphere. The LiMn 2 O 4 films were deposited on the Al substrates, and their film properties were evaluated by X-ray diffraction. The film thickness was estimated by the gravimetry method. It was shown that the film thickness and the deposition rate were proportional to the Ar：O 2 ratio as well as the sputtering time and the RF power. It was also shown that the deposition rate decreased as increasing the sputtering pressure.Keyword LiMn 2 O 4 thin film, RF magnetron sputtering, Li secondary batteries IntroductionRecently, an attention has been paid to the cars that run by using clean energy such as electric cells, fuel cells, and hybrid-power cells. They are intended to decrease the exhaust gases. However, there are a lot of problems of these cars. For example, the distance that they can run for one charge is short, the lifetime of battery is short, and the place that can be charged is few, etc.Then, we pay attention to the battery that is the source power of the electric car. Nickel hydride batteries are chiefly installed in the electric cars. They have excellent characteristics during the discharge with high-power and large current. They are also safety material. However, they have weak points, for example, increasing self-discharge, and the memory effect, so the capacity seems to decrease. These weak points would be resolved by using Li secondary batteries.