This disclosure provides a unique approach for the synthesis of non-stoichiometric, mesoporous metal oxides with nano-sized crystalline wall. The as-synthesized mesoporous metal oxide is very active and stable (durability>11 h) electocatalyst in both acidic and alkaline conditions. The intrinsic mesoporous metal oxide serves as an electrocatalyst without the assistant of carbon materials, noble metals, or other materials, which are widely used in previously developed systems. The as-synthesized mesoporous metal oxide has large accessible pores (2-50 nm), which are able to facilitate mass transport and charge transfer. The as-synthesized mesoporous metal oxide requires a low overpotential and is oxygen deficient. Oxygen vacancies and mesoporosity served as key factors for excellent performance.

The invention relates to a fluorination process consisting in bringing an inorganic compound M into contact with an atmosphere comprising difluorine gas, the inorganic compound M being a garnet based on the elements Li, La, Zr, A and O and for which the relative composition of the Li, La, Zr and A cations corresponds to the formula (I): Li.sub.xLa.sub.3Zr.sub.zA.sub.w.

A positive electrode active material that can achieve high thermal stability at low cost is provided.

Provided is a positive electrode active material for a lithium ion secondary battery, the positive electrode active material containing a lithium-nickel-manganese composite oxide, in which metal elements constituting the lithium-nickel-manganese composite oxide include lithium (Li), nickel (Ni), manganese (Mn), cobalt (Co), titanium (Ti), niobium (Nb), and optionally zirconium (Zr), an amount of substance ratio of the elements is represented as Li:Ni:Mn:Co:Zr:Ti:Nb=a:b:c:d:e:f:g (provided that, 0.97≤a≤1.10, 0.80≤b≤0.88, 0.04≤c≤0.12, 0.04≤d≤0.10, 0≤e≤0.004, 0.003<f≤0.030, 0.001<g≤0.006, and b+c+d+e+f+g=1), in the amount of substance ratio, (f÷g)≤0.030 and f>g are satisfied, and an amount of lithium to be eluted in water when the positive electrode active material is immersed in water is 0.20% by mass or less with respect to the entire positive electrode active material.

The method for producing a positive electrode active material for a lithium ion secondary battery includes preparing a mixture containing at least a nickel-manganese composite compound, a lithium compound, and optionally one or both of a titanium compound and a niobium compound. The method also includes firing the mixture from 750° C. to 1000° C. so as to obtain the lithium-nickel-manganese composite oxide, in which the nickel-manganese composite compound contains at least nickel, manganese, and an element M, an amount of substance ratio (z) of titanium and an amount of substance ratio (w) of niobium to a total amount of substance of nickel, manganese, the element M, titanium, and niobium in the mixture satisfy 0.005≤z≤0.05, 0.001<w≤0.03, (z+w)≤0.06, and z>w, and at least a part of the niobium is segregated to a grain boundary between primary particles.

A method for fabricating a composite material includes forming an emulsion mixture of active material particles and graphene emulsion droplets containing immiscible first and second solvents and a solid-state emulsifier of graphene, wherein the first and second solvents are adapted such that the second solvent resides in an interior of the graphene emulsion droplets with the first solvent as an exterior solvent, and the active material particles reside in the interior of the emulsion droplets; wherein a boiling point of the second solvent is lower than that of the first solvent; and drying the emulsion mixture with subsequent evaporation of the second solvent and the first solvent through fractional distillation to form the composite material having each surface of the active material particles conformally coated with said graphene.

A process for producing a lithium-manganese-nickel oxide spinel material includes maintaining a solution comprising a dissolved lithium compound, a dissolved manganese compound, a dissolved nickel compound, a hydroxycarboxylic acid, a polyhydroxy alcohol, and, optionally, an additional metallic compound, at an elevated temperature T.sub.1, where T.sub.1 is below the boiling point of the solution, until the solution gels. The gel is maintained at an elevated temperature until it ignites and burns to form a Li—Mn—Ni—O powder. The Li—Mn—Ni—O powder is calcined to burn off carbon and/or other impurities present in the powder. The resultant calcined powder is optionally subjected 1 to microwave treatment, to obtain a treated powder, which is annealed to crystallize the powder. The resultant annealed material is optionally subjected to microwave treatment. At least one of the microwave treatments is carried out. The lithium-manganese-nickel oxide spinel material is thereby obtained.

The present disclosure relates to a novel ruthenium oxide, a method of preparing the same, and a catalyst for selective hydrogenation of an aromatic compound or an unsaturated compound including the ruthenium oxide.

The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes a lithium composite oxide, and a lithium-aluminum-sulfur-boron oxide formed on a surface of the lithium composite oxide. A lithium secondary battery including the cathode active material and having improved stability and electrical properties is provided.

A solid electrolyte including a compound represented by Formula 1 or 3, the compound having a glass transition temperature of −30° C. or less, and a glass or glass-ceramic structure,
AQX—Ga.sub.1−zM.sub.z1(F.sub.1−kCl.sub.k).sub.3−3zZ.sub.3z1  Formula 1
wherein, in Formula 1, Q is Li or a combination of Li and Na, K, or a combination thereof, M is a trivalent cation, or a combination thereof, X is a halogen other than F, pseudohalogen, OH, or a combination thereof, Z is a monovalent anion, or a combination thereof, 1<A<5, 0≤z≤1, 0≤z1≤1, and 0≤k<1,
AQX-aM.sub.z1Z.sub.3z1-bGa.sub.1−z(F.sub.1−kCl.sub.k).sub.3−3z  Formula 3 wherein, in Formula 3, Q is Li or a combination of Li and Na, K, or a combination thereof; M is a trivalent cation, or a combination thereof, X is a halogen other than F, pseudohalogen, OH, or a combination thereof, Z is a monovalent anion, or a combination thereof, 0<a≤1, 0<b≤1, 0<a+b, a+b=4−A, 1<A<5, 0≤z<1, 0≤z1≤1, and 0≤k<1.