Preparation and Characterization of c‐LiMn2O4 Thin Films prepared by Pulsed Laser Deposition for Lithium‐Ion Batteries

Abstract

AbstractIn this work, lithium manganese oxide (LMO) thin films are prepared using pulsed laser deposition (PLD) at room temperature. The as‐prepared films are amorphous and require a subsequent annealing step to achieve dense films of c‐spinel LMO (LiMn2O4). We applied different annealing temperatures under an argon atmosphere to investigate the thermodynamics of the films and to find the minimum crystallization temperature. Thereby, a simple film deposition process with only one subsequent annealing step is developed to prepare crystalline films. The samples are characterized using scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS), X‐ray diffraction (XRD), thin‐film‐calorimetry, impedance spectroscopy, and electrochemical methods. The results indicate that a narrow temperature range around 700 °C is suitable for the preparation of the spinel phase. Using this preparation route, no further crystalline phases could be identified by XRD. The electrochemical properties of the films are investigated and compared to electrodes made of commercially available LMO powders. The electrochemical characterization shows a capacity of 95 mAh g−1 for the commercial powder and 110 mAh g−1 for the thin‐film samples.