Disclosed is a member for electrochemical devices comprising a current collector, an electrode mixture layer provided on the current collector, and an electrolyte layer provided on the electrode mixture layer in this order, wherein the electrode mixture layer comprises an electrode active material, a polymer having a structural unit represented by the following formula (1), at least one electrolyte salt selected from the group consisting of lithium salts, sodium salts, calcium salts, and magnesium salts, and a molten salt having a melting point of 250° C. or less, and the electrolyte layer comprises an inorganic solid electrolyte:

##STR00001##

wherein X.sup.− represents a counter anion.

A solid-state electrolyte having a garnet-type crystal structure represented by the formula (Li.sub.7−ax+yA.sub.x)La.sub.3(Zr.sub.2−yB.sub.y)O.sub.12, where A is at least one element selected from Mg, Zn, Al, Ga, and Sc, a is a valence of A, B is at least one element selected from Al, Ga, Sc, Yb, Dy, and Y, x is more than 0 and less than 1.0, y is more than 0 and less than 1.0, and 7−ax+y is more than 5.5 and less than 7.0).

The electrochemical cell includes an anode, a cathode active layer, and a solid electrolyte layer disposed between the anode and the cathode active layer. The cathode active layer includes a first region which is disposed facing the solid electrolyte layer, and a second region which is disposed on the first region. An average particle diameter of first constituent particles which constitute the first region is smaller than an average particle diameter of second constituent particles which constitute the second region.

Disclosed is a rapid, reproducible solution-based method to synthesize solid sodium ion-conductive materials. The method includes: (a) forming an aqueous mixture of (i) at least one sodium salt, and (ii) at least one metal oxide; (b) adding at least one phosphorous precursor as a neutralizing agent into the mixture; (c) concentrating the mixture to form a paste; (d) calcining or removing liquid from the paste to form a solid; and (e) sintering the solid at a high temperature to form a dense, non-porous, sodium ion-conductive material. Solid sodium ion-conductive materials have electrochemical applications, including use as solid electrolytes for batteries.

This invention provides a ceramic powder capable of forming a sintered body having a high density and high ionic conductivity even at a sintering temperature lower than the temperature conventionally used, and provides a battery containing a sintered body of the ceramic powder as a constituent element. The above problem is solved by a ceramic powder containing a garnet-type oxide and compound 1, wherein the garnet-type oxide contains zirconium, lithium, and lanthanum, and compound 1 contains at least one metal element selected from the group consisting of lanthanum, lithium, zirconium, gallium, scandium, yttrium, cerium, aluminum, calcium, magnesium, barium, strontium, niobium, and tantalum.

The fuel cell of the present disclosure includes: a unit cell including: a fuel electrode, an air electrode and electrolyte disposed between the fuel electrode and the air electrodes; a separator for separating a fuel gas flowing though the fuel electrode and air flowing through the air electrode; and a sealing constituted of a glass composition for bonding the separator and the electrolyte, and at least a surface region of the sealing portion exposed to the fuel gas and the air does not contain Ba.

Methods of forming sintered compounds and compounds formed using the methods are disclosed. Exemplary methods include reactive flash sintering to form sintered compounds from two or more starting compounds. Various sintered compounds may be suitable for use as solid electrolytes in solid-state electrochemical cells and batteries.

Provided are: an ion-conductive solid which can be produced by heat treatment at a low temperature and which has high ion conductivity; and, an all-solid-state battery having the ion-conductive solid. An ion-conductive solid containing an oxide represented by the general formula Li.sub.6-3a-2b-c-dYi.sub.1-c-dAl.sub.aMg.sub.bZr.sub.cCe.sub.dB.sub.3O.sub.9; and, an all-solid-state battery having at least a positive electrode, a negative electrode, and an electrolyte, at least one element selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte containing the ion-conductive solid (In the formula, a is such that 0.000a0.800, b is such that 0.000b0.800, c is such that 0.000c0.400, d is such that 0.000d0.400, and a and b are real numbers satisfying 0.005a+b0.800.).

The present specification relates to an electrolyte of a solid oxide fuel cell, a solid oxide fuel cell including the same, a composition for the electrolyte, and a method for preparing the electrolyte.

The present invention relates to a proton ceramic fuel cell which has a hydrogen-permeable film as an anode and in which an electrolyte material is BaZr.sub.xCe.sub.1-x-yY.sub.zO.sub.3 (x=0.1 to 0.8, z=0.1 to 0.25, x+z1.0) (BZCY). An electron-conducting oxide thin film having a film thickness of 1-100 nm is present between a cathode and an electrolyte comprising the material. The present invention also relates to a method for producing a proton ceramic fuel cell having a hydrogen-permeable film as an anode. The method comprises forming a thin film having a thickness of 1-100 nm between a cathode and an electrolyte comprising BZCY, the thin film comprising an electron-conducting oxide. The present invention provides a novel means for improving the output of a PCFC in which BZCY is used in an electrolyte material, and provides a PCFC having an output that exceeds a benchmark of 0.5 W cm.sup.2 at 500 C.