This invention reports a novel design and a facile synthetic approach of a new class of sodium oxysulfide electrolyte for the applications in all-solid-state sodium batteries. This new electrolyte system is synthesized of Na2S-P2S5-P2O5 with a molar ratio of 75:(25-X):X (X=1.5, 3.0, 6.0) and will enable the use of Na metal for high energy and safe batteries for energy storage.