A Study Of One Kind Of Solid Electrolyte Called LiPON

A battery is asked to be smaller, lighter and to provide higher capacity and so on. In recent years, the all-solid-state thin film Li-ion battery has been developed because of above advantages. There are a multitude of researches about its cathode and anode. However, there is little study about thin film electrolyte. In particular, there are few systemic researches on electrolytes’ conduction mechanism and new kind of electrolytes. Therefore, the traditional thin film electrolyte LiPON becomes the subject investigated in this paper. The experiment and results are listed as followings:1. The thin film LiPON has been made by RF sputtering. The thin film Al has been made by DC sputtering. Finally, a sandwich structure Al-LiPON-Al has been fabricated. The film has been investigated through several methods- XPS, XRD, SEM. An electrochemical workstation is used for the measurement of ionic conductivity. All data show that, element ratios of LiPON is appropriate, and it is amphorous and compact. Its ionic conductivity is 5.4×10-7S/cm,which all prove that the LiPON is suitable as one kind of solid electrolyte.2. The annealing procedure of the film LiPON at N2 and air is finished. The temperature range is 600~800℃, and the time range is 1~10h. The film after annealing has been investigated through several methods- XPS, XRD, SEM. All date show that when the annealing temperature is below 600℃, there is no obvious change about LiPON thin film. If the annealing temperature is higher than 600℃, with the increasing of annealing temperature and time, its content of N is decreased. By the way, the film’s amorphous phase can’t be remained well, and the basement is exposed. All mean that the thin film LiPON is not suitable to be used as a kind of solid electrolyte.3. In the air, the film LiPON will suffer hydrolysis. The humidity is 25%, 50% and 75%, and the time range is 6~24h. The film after hydrolysis has been investigated through several methods-XPS, SEM. All dates show that after hydrolysis, the content of N,P will decrease, C,O will increase. At the same time, there will be some hydrolysis centers, their size and number is increasing. It means that the film is not suitable to be used as one kind of solid electrolyte.