Synthesizing lithium lanthanum zirconate includes combining a reagent composition with a salt composition to yield a molten salt reaction medium, wherein the reagent composition comprises a lithium component, a lanthanum component, and zirconium component having a lithium:lanthanum:zirconium molar ratio of about 7:3:2; heating the molten salt reaction medium to yield a reaction product; and washing the reaction product to yield a crystalline powder comprising lithium lanthanum zirconate.

A sintered composite ceramic includes: a lithium-garnet major phase; and a lithium-rich minor phase, such that the lithium-rich minor phase has Li.sub.xTiO.sub.(x+4)/2, with 0.66x4. The sintered composite ceramic may exhibit a relative density of at least 90% of a theoretical maximum density of the ceramic, an ionic conductivity of at least 0.35 mS.Math.cm.sup.1, or a critical current density (CCD) of at least 1.0 mA.Math.cm.sup.2.

A glass ceramic containing lithium-ions and having a garnet-like main crystal phase having an amorphous proportion of at least 5% is disclosed. The garnet-like main crystal phase preferably has the chemical formula Li.sub.7+xyM.sub.x.sup.IIM.sub.3x.sup.IIIM.sub.2y.sup.IVM.sub.y.sup.VO.sub.12, wherein M.sup.II is a bivalent cation, M.sup.III is a trivalent cation, M.sup.IV is a tetravalent cation, M.sup.V is a pentavalent cation. The glass ceramic is prepared by a melting technology preferably within a Skull crucible and has an ion conductivity of at least 5.Math.10.sup.5 S/cm, preferably of at least 1.Math.10.sup.4 S/cm.

An electrochemical cell includes a fuel electrode, an air electrode containing a perovskite type oxide as a main component, the perovskite type oxide being represented by a general formula ABO.sub.3 and containing La and Sr at the A site, and a solid electrolyte layer arranged between the fuel electrode and the air electrode. The air electrode includes a center portion and an outer peripheral portion, the center portion being located at a center of the air electrode in a plane direction perpendicular to a thickness direction of the air electrode, the outer peripheral portion surrounding the center portion in the plane direction. A first ratio of an La concentration to an Sr concentration detected at the outer peripheral portion through Auger electron spectroscopy is at least 1.1 times a second ratio of an La concentration to an Sr concentration detected at the center portion through Auger electron spectroscopy.

Provided is an ionic conductor that, as a molded article that has been press-molded without firing, can exhibit a high lithium ionic conductivity. The ionic conductor comprises an ionic conductive powder that has a garnet structure or garnet-like structure containing at least Li, La, Zr, and O. This ionic conductor further comprises an ionic liquid that exhibits lithium ion conductivity. The ionic conductor has a lithium ion conductivity at 25 C. of at least 1.010.sup.5 S/cm.

A proton-conductive cell structure includes an air electrode, a hydrogen electrode, and a solid electrolyte layer disposed between the air electrode and the hydrogen electrode, wherein the solid electrolyte layer includes at least a first solid electrolyte layer formed of a compact material. The first solid electrolyte layer includes a metal oxide having a perovskite structure and represented by Formula 1 below, a ratio of Sr to a total amount of Ba and Sr in an air-electrode-side near-surface region of the first solid electrolyte layer is 0.4 or more, and a ratio of Sr to a total amount of Ba and Sr in a hydrogen-electrode-side near-surface region of the first solid electrolyte layer is 0.003 to 0.3.

Ba.sub.x1Sr.sub.x2A.sub.1-yM.sub.yO.sub.3-(1)

A method of manufacturing a lithium solid electrolyte, the method including: providing a composition including a lithium precursor, a lanthanum precursor, and a zirconium precursor; disposing the composition on a substrate having a temperature of 270 C. to 500 C. to form a film; and heat-treating the film at 300 C. to less than 750 C. for 1 hour to 100 hours to manufacture the lithium solid electrolyte.

An electrochemical cell stack according to a first aspect of the present invention includes an electrochemical cell and a manifold supporting a base end of the electrochemical cell. The electrochemical cell includes an electric insulative support substrate and a plurality of power generation units disposed on the support substrate. Additionally, a gas flow path is provided in the support substrate. Each of the plurality of power generation units includes an anode, a cathode, and a solid electrolyte layer disposed between the anode and the cathode. Additionally, the solid electrolyte layer contains a zirconia-based material as a main component thereof. In a distal end side power generation unit, which is farthest from the manifold among the plurality of power generation units, the solid electrolyte layer includes a first area covering within 3 m from an anode side surface, and a second area provided on the first area. An intensity ratio of tetragonal zirconia to cubic zirconia in a Raman spectrum in the first area is greater than an intensity ratio of tetragonal zirconia to cubic zirconia in the Raman spectrum in the second area.

An electrochemical cell stack according to a second aspect of the present invention includes an electrochemical cell and a manifold supporting a base end of the electrochemical cell. The electrochemical cell includes an electric conductive support substrate and a power generation unit disposed on the support substrate. Additionally, a gas flow path is provided in the support substrate. The power generation unit includes an anode disposed on a first main surface of the support substrate, a cathode, and a solid electrolyte layer disposed between the anode and the cathode. Additionally, the solid electrolyte layer contains a zirconia-based material as a main component thereof. The solid electrolyte layer includes a base end portion positioned on a side of the base end and a separated portion positioned separated from the base end. The base end portion includes a first area covering within 3 m from an anode side surface, and a second area provided on the first area. An intensity ratio of tetragonal zirconia to cubic zirconia in a Raman spectrum in the first area is greater than an intensity ratio of tetragonal zirconia to cubic zirconia in the Raman spectrum in the second area.

An article for forming an electrochemical device is disclosed. The article comprises a metallic current collector clad with an ion conducting solid-electrolyte material such that intimate contact between the current collector and the ion conducting solid-electrolyte material is made. A lithium metal anode can be formed in situ between the current collector clad and the ion conducting solid-electrolyte material from lithium ions contained within a cathode material that is placed in contact with the ion conducting solid-electrolyte material. A bipolar electrochemical cell can be constructed from the article.