The invention relates to an ion-conducting glass having a conductivity of up to 10<-3> OMEGA <-1> cm<-1> at 300 DEG C at the same time as relatively high hydrolysis resistance and favourable production and processing properties. This is achieved according to the invention in that the glass comprises at least sodium oxide, aluminium oxide, boron trioxide and silicon dioxide and has the following composition: from 25 to 55 mol% of Na2O from 15 to 25 mol% of Al2O3 from 15 to 25 mol% of B2O3 from 15 to 30 mol% of SiO2. Glass of this type is suitable for use as solid electrolyte in batteries which permit adequate current consumption based on electrochemical reactions between sodium and suitable co-reactants, such as halogens or sulphur.
