A positive active material for a rechargeable lithium battery, a preparing method thereof, and a rechargeable lithium battery including the same are provided. The positive active material for a rechargeable lithium battery includes a first positive active material including a first lithium nickel-based composite oxide and including secondary particles formed by aggregation of a plurality of primary particles and a cobalt coating portion on the surface of the secondary particles; and a second positive active material including a second lithium nickel-based composite oxide and including individual particles and a cobalt coating portion on the surface of the individual particles, wherein the second positive active material has an uneven surface having concavo-convex features and an even surface that is substantially flat.

Provided is a novel solid electrolyte material of high density and high ionic conductivity, and an all-solid-state lithium ion secondary battery that utilizes the solid electrolyte material. The solid electrolyte material has a chemical composition represented by Li.sub.7-3xGa.sub.xLa.sub.3Zr.sub.2O.sub.12 (0.08≤x<0.5), has a relative density of 99% or higher, belongs to space group I-43d, in the cubic system, and has a garnet-type structure. The lithium ion conductivity of the solid electrolyte material is 2.0×10.sup.−3 S/cm or higher. The solid electrolyte material has a lattice constant a such that 1.29 nm≤a≤1.30 nm, and lithium ions occupy the 12a site, the 12b site and two types of 48e site, and gallium occupies the 12a site and the 12b site, in the crystal structure. The all-solid-state lithium ion secondary battery has a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte is made up of the solid electrolyte material of the present invention.

A method for preparing a solid-state electrolyte powder includes the following steps. An oxygen-free sintering process is performed at a first sintering temperature, such that a refined salt mixture forms a solid-state electrolyte powder precursor mixture. An oxygen-containing sintering process is performed at a second sintering temperature, such that the solid-state electrolyte powder precursor mixture forms a solid-state electrolyte powder, in which the second sintering temperature is higher than the first sintering temperature.

A battery comprising an acidified metal oxide (“AMO”) material, preferably in monodispersed nanoparticulate form 20 nm or less in size, having a pH<7 when suspended in a 5 wt % aqueous solution and a Hammett function H.sub.0>−12, at least on its surface.

A supported catalyst for decomposing an organic substance that includes a support and a catalyst particle supported on the support. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni and Fe, y+z=1, x≥0.995, z≤0.4, and w is a positive value satisfying electrical neutrality. A film thickness of a catalyst-supporting film supported on the support and containing the catalyst particle is 5 μm or more, or a supported amount as determined by normalizing a mass of the catalyst particle supported on the support by a volume of the support is 45 g/L or more.

Described are lithium transition metal halides which have ionic conductivity for lithium ions, a process for preparing them, their use as a solid electrolyte for an electrochemical cell, and electrochemical cells comprising lithium transition metal halides.

The present disclosure discloses an ABO.sub.3 type high-entropy perovskite Ba.sub.x(FeCoNiZrY).sub.0.2O.sub.3-δ electrocatalytic material and a preparation method thereof, belonging to the technical field of electrocatalytic materials. The electrocatalytic material is prepared by taking hydrated cobalt nitrate, hydrated ferric nitrate, hydrated nickel nitrate, barium nitrate, hydrated yttrium nitrate, hydrated zirconium nitrate and polyacrylonitrile staple fibers as raw materials through processes of liquid phase chelation, gelation, calcination, etc. The prepared high-entropy perovskite Ba.sub.x(FeCoNiZrY).sub.0.2O.sub.3-δ electrocatalytic material can release more electrochemical active sites due to its special nanostructure, thus showing better electrocatalytic activity. Meanwhile, by adjusting the stoichiometric ratio of A/B-site metals, the electronic structure change of five metals in a catalytic center and the change of an oxygen vacancy content are realized, and the purpose of adjusting and optimizing the nitrogen reduction performance is achieved, so that the electrocatalytic material has excellent electrocatalytic conversion of nitrogen gas into ammonia gas.

Provided is a friction modifier giving excellent formability in producing a friction material and capable of reducing rust formation on a rotor even when the moisture-absorbed friction material is left pressed against the rotor for a long. The friction modifier is made of a titanate compound having a tunnel crystal structure, wherein the titanate compound has a rate of chlorine ion dissolution of 0.5 ppm to 400 ppm.

A multilayer ceramic capacitor includes: a multilayer structure in which ceramic dielectric layers and internal electrode layers are alternately stacked, wherein: a main component of the ceramic dielectric layer is barium titanate in which a donor element having a larger valence than Ti is solid-solved and an acceptor element having a smaller valence than Ti and larger ion radius than Ti and the donor element is solid-solved; a solid-solution amount of the donor element is 0.05 mol or more and 0.3 mol or less on a presumption that an amount of the barium titanate is 100 mol and the donor element is converted into an oxide; and a solid solution amount of the accepter element is 0.02 mol or more and 0.2 mol or less on a presumption that the amount of the barium titanate is 100 mol and the acceptor element is converted into an oxide.

Provided is a method for producing a phosphor, using a nitride raw material, that gives a high-reliability (Sr,Ca)AlSiN.sub.3-based nitride phosphor at a productivity higher than before. The method comprises a mixing step of mixing raw materials and a calcining step of calcining the mixture obtained in the mixing step and, in producing the phosphor having a crystalline structure substantially identical with that of (Sr,Ca)AlSiN.sub.3 crystal as the host crystal, a strontium nitride containing SrN, Sr.sub.2N, or the mixture thereof as the main crystalline phase, as determined by crystalline phase analysis by powder X-ray diffractometry, and having a nitrogen content of 5 to 12 mass % is used as part of the raw materials.