An oxide electrolyte sintered body with high lithium ion conductivity and a method for producing the same, which can obtain the oxide electrolyte sintered body with high lithium ion conductivity by sintering at lower temperature than ever before. The method for producing an oxide electrolyte sintered body may comprise the steps of: preparing crystal particles of a garnet-type ion-conducting oxide which comprises Li, H, at least one kind of element L selected from the group consisting of an alkaline-earth metal and a lanthanoid element, and at least one kind of element M selected from the group consisting of a transition element that can be 6-coordinated with oxygen and typical elements belonging to the Groups 12 to 15, and which is represented by a general formula (Li.sub.x−3y−z,E.sub.y,H.sub.z)L.sub.αM.sub.βO.sub.γ (where E is at least one kind of element selected from the group consisting of Al, Ga, Fe and Si, 3≦x−3y−z≦7, 0≦y<0.22, 0<z≦2.8, 2.5≦α≦3.5, 1.5≦β≦2.5, and 11≦γ≦13); preparing a lithium-containing flux; and sintering a mixture of the crystal particles of the garnet-type ion-conducting oxide and the flux by heating at 400° C. or more and 650° C. or less.

A composite article comprises a substrate, the substrate comprising a silicon containing material and an additive comprising boron nitride nanotubes.

Disclosed herein are doped perovskite oxides. The doped perovskite oxides may be used as a cathode material in an electrochemical cell to electrochemically generate ammonia from N.sub.2. The doped perovskite oxides may be combined with nitride compounds, for instance iron nitride, to further increase the efficiency of the ammonia production.

Disclosed are a ten-membered fergusonite structure high-entropy oxide ceramic and a preparation method thereof, where the high-entropy oxide ceramic has a monoclinic structure, with a chemical formula of RENbO.sub.4, and the RE is any ten rare-earth cations selected from a group consisting of La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, Yb.sup.3+, Lu.sup.3+ and Y.sup.3+. The ten rare-earth cations have a molar ratio of 1:1:1:1:1:1:1:1:1:1 and equal share of RE position. According to the application, by adopting solid state reaction, the fergusonite structure high-entropy oxide ceramic with single-phase structure, uniform element distribution and stable phase is obtained. The high-entropy oxide ceramic prepared by the application is simple in process, uniform in chemical composition and microstructure, and convenient to realize on-demand regulation on properties through a combination of different elements.

A lead-free piezoelectric ceramic composition mainly includes a first crystal phase (KNN phase) and a second crystal phase (NTK phase). In the first crystal phase (KNN phase), a plurality of crystal grains formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics is bound to each other in a deposited state. The second crystal phase (NTK phase) is formed of a compound containing titanium (Ti) and fills spaces between the crystal grains in the first crystal phase.

A method of preparing a lithium lanthanum zirconate (LLZO) cubic garnet material is provided which comprises the following steps: (a) milling a slurry comprising one or more precursor compounds in an aqueous medium, wherein the one or more precursor compounds comprise lithium, lanthanum, zirconium and optionally one or more dopant elements, to provide a milled slurry; (b) spray drying the milled slurry to provide a spray-dried powder; and (c) annealing the spray-dried powder. The resultant LLZO cubic garnet material may be used as a lithium ion conductive solid electrolyte in secondary lithium-ion batteries.

Disclosed is a solid state electrolyte comprising a compound of Formula 1

Li.sub.7-.sub.a.sub.*α-(b−4)*β−xM.sup.a.sub.αLa.sub.3Hf.sub.2−βM.sup.b.sub.βO.sub.12−x−δX.sub.x   (1)

wherein

M.sup.a is a cationic element having a valence of a+;

M.sup.b is a cationic element having a valence of b+; and

X is an anion having a valence of −1,

wherein, when M.sup.a includes H, 0≤α≤5, otherwise 0≤α≤0.75, and wherein 0≤β≤1.5, 0≤x≤1.5, and (a*α+(b−4)β+x)>0, 0≤δ≤1.

A precursor of an alumina sintered compact including aluminum, yttrium, and at least one metal selected from iron, zinc, cobalt, manganese, copper, niobium, antimony, tungsten, silver, and gallium. The aluminum content is 98.0% by mass or more as an oxide (Al.sub.2O.sub.3) in 100% by mass of the precursor of an alumina sintered compact; the yttrium content is 0.01 to 1.35 parts by mass as an oxide (Y.sub.2O.sub.3) based on 100 parts by mass of the content of the aluminum as an oxide; the total content of the metals selected from the foregoing group is 0.02 to 1.55 parts by mass as an oxide based on 100 parts by mass of the content of aluminum as an oxide; and the aluminum is contained as α-alumina. Also disclosed is an alumina sintered compact, and a method for producing an alumina sintered compact and for producing abrasive grains.

A ceramic and a preparation method therefor are provided. The ceramic includes a zirconia matrix, and an additive dispersed inside and on an outer surface of the zirconia matrix. The additive is an oxide including elements A and B, where A is selected from at least one of Ca, Sr, Ba, Y, and La, and B is selected from at least one of Cr, Mn, Fe, Co, and Ni.

A composite ceramic including: a lithium garnet major phase; and a grain growth inhibitor minor phase, as defined herein. Also disclosed is a method of making composite ceramic, pellets and tapes thereof, a solid electrolyte, and an electrochemical device including the solid electrolyte, as defined herein.