A method of forming a solid state battery is disclosed. In a moisture-free inert atmosphere, the method includes combining unreacted solid electrolyte precursors to form a green sheet, stacking the green sheet in between porous electrodes to form a solid state battery, and heating the battery to a melting point temperature of the precursors such that the precursors form a liquid phase penetrating pores in the electrodes to form ion conducting channels in the battery.