Development of all solid state fluoride ion batteries based on thin film electrolytes

Abstract

For current solid state fluoride ion battery, a critical problem is that the practical capacity is considerably below that of the theoretical value and fades rapidly during the further cycles. One reason for this problem might be the thick solid electrolyte layer of this system, which, for mechanical reasons, has a thickness of 700 – 800 µm. The thickness can cause a high resistance, leading to a poor electrochemical performance. Therefore, a thin film electrolyte may be a promising approach to improve the performance of the solid state fluoride ion battery, due to its improved overall ionic conductance. The thin film electrolyte for fluoride ion battery is studied in this thesis, including the optimal composition of the electrolyte, the optimal preparation conditions and the electrochemical performance of the fluoride ion batteries using the thin film electrolyte. Naturally, this new energy storage system still has some problems, but potential solutions were proposed in the thesis. This PhD work opened a new door and more efforts will be distributed on this topic in the future.