Thin film amorphous electrolytes: The Li sub 2 O-SiO sub 2 -P sub 2 O sub 5 system

Abstract

Thin film amorphous electrolytes with compositions xLi{sub 2}O: ySiO{sub 2}:zP{sub 2}O{sub 5} were deposited by single and dual source rf magnetron sputtering and their compositions determined by electron and ion beam techniques. Films containing P but no Si were composed of mainly orthophosphate and some linear chain phosphate anions, whereas single phase films containing Si and P were evidently composed of branched and possible cyclic and extended network structures. Films with Si/P>1 appeared to contain two or more amorphous phases. In the range of compositions investigated, the lithium ion conductivity depends mainly on the lithium ion mobility which is sensitive to the structure of the films. An open circuit voltage from 1 to 3 V measured between blocking metal contacts on the electrolyte thin films suggest that the films might be electrets. 18 refs., 5 figs., 2 tabs