Conductivity of lithium borophosphate glasses for thin film solid electrolyte of lithium battery

Abstract

Inorganic glass has been studied for long time as a candidate for solid state electrolyte material of the rechargeable thin film battery which can be applied to electronic devices such as micro-electro-mechanical system, smart card, medical appliances, and so on. It has been recognized that the major limitation of glass electrolyte is the low lithium ion mobility while the electrochemical stability and the chemical inertness against the active materials employed lithium battery are regarded as major advantages. The application of the glass electrolyte to conventional bulk type battery, hence, is impractical in spite of its merits and the researches on this group of materials are diminishing recently. However, if the lithium ion resistance is reduced to the reasonable level, the glass electrolyte can be a good candidate for solid state electrolyte. The reduction of resistance can be achieved by reducing the thickness of electrolyte to a few micrometers range, which can be easily achieved by thin film fabrication technologies and is necessary for the thin film battery. In this study, the structural variation of the oxide amorphous electrolytes of Li2O-B2O3-P2O5 system was investigated by Raman spectroscopy to find out the correlation with the electrical conductivity and to seek the best composition among the various compositions of this material system, for the deposition of thin film electrolytes.