A cathode configured to use oxygen as a cathode active material includes: a porous film including a metal oxide, where a porosity of the porous film is about 50 volume percent to about 95 volume percent, based on a total volume of the porous film, and an amount of an organic component in the porous film is 0 to about 2 weight percent, based on a total weight of the porous film.

A composite solid state electrolyte comprises a polymer electrolyte material, a ceramic ion conductor, and a functionalized coupling agent selected to be compatible with the ceramic ion conductor and the bulk polymer compound. The polymer electrolyte material comprises a bulk polymer compound and a lithium salt. The functionalized coupling agent has a backbone that is structurally similar to the bulk polymer compound.

Disclosed herein are embodiments of doped and undoped spherical or spheroidal lithium lanthanum zirconium oxide (LLZO) powder products, and methods of production using microwave plasma processing, which can be incorporated into solid state lithium ion batteries. Advantageously, embodiments of the disclosed LLZO powder display a high quality, high purity stoichiometry, small particle size, narrow size distribution, spherical morphology, and customizable crystalline structure.

A thermal barrier coating material contains a compound X that is a cation-deficient-type defective perovskite complex oxide. Unit cells of the compound X each include six oxygen atoms and has a structure in which two octahedrons sharing one oxygen atom are aligned. In the compound X, central axes of two octahedrons that belong to adjacent unit cells, respectively, and are adjacent to each other are inclined relative to each other. A plurality of sets of the two octahedrons that belong to the adjacent unit cells, respectively, and are adjacent to each other are arranged to form a periodic structure in which octahedrons having different inclinations are alternately arranged, and the compound X has a boundary surface at which a periodicity of the periodic structure changes, in a crystal structure thereof.

A mixed conductor represented by Formula 1:
A.sub.4+xM.sub.5-yM′.sub.yO.sub.12-δ,  Formula 1
wherein, in Formula 1, A is a monovalent cation, M is at least one of a divalent cation, a trivalent cation, or a tetravalent cation, M′ is at least one of a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation, M and M′ are different from each other, and 0.3≤x<3, 0.01<y<2, and 0≤δ≤1 are satisfied.

A solid electrolyte according to the present disclosure is represented by the following compositional formula (1).

Li.sub.7-x(La.sub.3-zY.sub.z)(Zr.sub.2-xM.sub.x)O.sub.12  (1)

In the formula (1), x and z satisfy 0.00<x<1.10, and 0.00<z≤0.15, and M is two or more types of elements selected from the group consisting of Nb, Ta, and Sb.

Provided is a dielectric composition which includes, as a main component, a complex oxide represented by a general formula A.sub.aB.sub.bC.sub.4O.sub.15+α and having a tungsten bronze structure, wherein “A” includes at least Ba, “B” includes at least Zr, “C” includes at least Nb, “a” is 3.05 or higher, and “b” is 1.01 or higher. In the dielectric composition, when the total number of atoms occupying M2 sites in the tungsten bronze structure is set to 1, the proportion of “B” is 0.250 or higher. In addition, in the dielectric composition, an X-ray diffraction peak of a (410) plane of the tungsten bronze structure is splitted into two, and an integrated intensity ratio of an integrated intensity of a high-angle side peak of the X-ray diffraction peak with respect to an integrated intensity of a low-angle side peak of the X-ray diffraction peak is 0.125 or higher.

[Object] It is an object of the present invention to provide a lithium tantalate single crystal substrate which undergoes only small warpage, is free from cracks and scratches, has better temperature non-dependence characteristics and a larger electromechanical coupling coefficient than a conventional Y-cut LiTaO.sub.3 substrate. [Means to solve the Problems] The lithium tantalate single crystal substrate of the present invention is a rotated Y-cut LiTaO.sub.3 single crystal substrate having a crystal orientation of 36° Y-49° Y cut characterized in that: the substrate is diffused with Li from its surface into its depth such that it has a Li concentration profile showing a difference in the Li concentration between the substrate surface and the depth of the substrate; and the substrate is treated with single polarization treatment so that the Li concentration is substantially uniform from the substrate surface to a depth which is equivalent to 5-15 times the wavelength of either a surface acoustic wave or a leaky surface acoustic wave propagating in the LiTaO.sub.3 substrate surface.

A solid electrolyte including: an oxide represented by Formula 1, Formula 2, Formula 3, or a combination thereof,

Li.sub.2+4xM1.sub.1−xO.sub.3  Formula 1

wherein, in Formula 1, M1 is hafnium, titanium, zirconium, or a combination thereof, and 0<x<1;

Li.sub.2−y(a−4)M1.sub.1−yM2.sup.a.sub.yO.sub.3  Formula 2

wherein, in Formula 2, M1 is hafnium, titanium, zirconium, or a combination thereof, M2 is at least one element having an oxidation number of a, and wherein a is an integer from 1 to 6, and 0<y<1; or

Li.sub.2−zM1O.sub.3−zX.sub.z  Formula 3

wherein, in Formula 3, M1 is hafnium, titanium, zirconium, or a combination thereof, X is a halogen, a pseudohalogen, or a combination thereof, and 0<z<2.

An ion conductor including: at least one oxide represented by Formulae 1 to 3

Li.sub.4±xM.sub.1−x′M′.sub.x′O.sub.4   Formula 1

wherein in Formula 1, 0≤x≤1 and 0≤x′≤1 , M is a Group 4 element,

M′ is an element of Group 2, an element of Group 3, an element of Group 5, an element of Group 12, an element of Group 13, a vacancy, or a combination thereof, with the proviso that when M is Zr, then x≠0, x′≠0 and M′ is Be, Ca, Sr, Ba, Ra, Cd, Hg, Cn, Ga, In, TI, an element of Group 3, an element of Group 5, or a combination thereof;

Li.sub.4−yM″O.sub.4−yA′.sub.y   Formula 2

wherein in Formula 2, M″ is a Group 4 element, A′ includes at least one halogen, with the proviso that when M″ is Zr, y≠0,

Li.sub.4+4zM′″.sub.1−zO.sub.4   Formula 3

wherein in Formula 3, 0<z<1, and M″′ is a Group 4 element.