An ion conductor/electrolyte especially suitable for lithium batteries is comprised of a chemically inert, electronically nonconducting solid powder and an electrolyte salt solution with an aprotic solvent. The ion conductor has a solid to pasty consistency depending upon the ratio of the mixture's components and has a specific conductivity (.kappa.) of a magnitude >10.sup.-3 S/cm at room temperature. Using this ion conductor, solid batteries can be developed with output capacities similar to those previously available only in connection with liquid organic electrolyte systems. Among others, SiO.sub.2, Al.sub.2 O.sub.3 and TiO.sub.2 are favorable solids as carriers, especially with extensive surface areas. The liquid phase, which is immobilized by adsorption on these carriers, is formed of a solution of lithium or sodium salts in propylene carbonate, acetonitrile, gamma-butyrolactone, nitromethane, tetrahydrofuran and dimethoxyethane, or similar solvents.