Abstract: Solid-state batteries offer improved safety and the high-energy-density capabilities required for next generation demands of electric vehicles. Disclosed is a method for fabricating high-current-density solid-state batteries, and the associated device structures and systems. The method of fabrication includes purifying surfaces of a solid electrolyte, depositing materials to form deposition layers on the surfaces of the solid electrolyte in a vacuum, and forming oxygen-deficient interfaces at the interface of the deposition layers and the solid electrolyte. The methods and associated devices form high-current-density solid-state batteries with stable electrochemical performance over hundreds of electric cycles.