Method of making a solid electrolyte separator

Claim 1

In the making of a solid electrolyte separator for separating a molten alkali metal anode from a molten salt electrolyte in a high temperature electrochemical power storage cell by: forming a composite layered artifact comprising at least two layers of solid electrolyte material or a precursor thereof arranged face-to-face, at least one of said layers being capable of providing, after sintering, a dense non-porous sintered layer, at least one of said layers being an outer layer capable of providing, after sintering, a porous sintered layer comprising a plurality of interconnected channels or pores, and at least one of each adjacent pair of said layers being a green layer capable of being sintered to form a sintered layer; and heating said composite artifact to a temperature at which each green layer becomes a sintered layer and becomes integrally bonded to each adjacent layer, to form a unitary sintered artifact; the improvement whereby at least one said outer layer which is capable of providing, after sintering, a porous sintered layer comprising a plurality of interconnected channels or pores is a said green layer which is capable of being sintered to form a sintered layer and contains a pore-forming material which is driven therefrom by the heating to leave said interconnected channels or pores, the pore-forming material being selected from the group consisting of carbon and materials which carbonize before burning when heated, the heating being under an oxygen-containing atmosphere and acting to burn away the pore-forming material.