Abstract: The invention provides a method of making a ceramic solid electrolyte separator for a high temperature electrochemical cell from a particulate starting material capable of being sintered to form a unitary polycrystalline solid electrolyte ceramic artifact. The method includes admixing the particulate starting material with a binder to form an extrudable mixture, extruding the mixture to form a unitary sinterable green artifact including a multiplicity of at least five tubes interconnected together in side-by-side relationship and sintering the green artifact to form a sintered polycrystalline ceramic solid electrolyte artifact. The artifact includes a multiplicity of at least five ceramic solid electrolyte separator tubes interconnected together by sintering and arranged in side-by-side relationship.