This paper presents glassy films of lithium phosphorus oxynitride electrolyte with an amorphous structure and improved ionic conductivity suitable for solid???state batteries. The films of lithium phosphorus oxynitride electrolyte were obtained by deposition using the RF sputtering technique in a reactive N2 atmosphere. The measurements showed films with ionic conductivities in range of 10??? 7???10??? 6 S??cm??? 1, for temperatures between 22 ??C and 43 ??C. The depositions were done at several pressures (0.03 Pa, 0.7 Pa and 1 Pa) and for RF applied powers of 150 W and 200 W, in order to evaluate the best deposition set???point. The highest ionic conductivity of 10??? 6 S??cm??? 1 was measured under a practical room temperature of 35 ??C on the best films. These results are comparable with the related state???of???the???art.