The breakage or cracking of a positive electrode active material due to pressure application, repeated charging and discharging, or the like is likely to cause dissolution of a transition metal, an excessive side reaction, and the like. With a crack, unevenness, a step, roughness, or the like on the surface of a positive electrode active material, stress tends to be concentrated on part, which easily causes breakage. By contrast, with a smooth surface and a nearly spherical shape, stress concentration is alleviated; thus, breakage is unlikely to occur. Therefore, a positive electrode active material with a smooth surface and little unevenness is formed. For example, when the positive electrode active material is subjected to image analysis using a microscope image, the median value of the solidity is larger than or equal to 0.96. Alternatively, the median value of the fractal dimension of the positive electrode active material is smaller than or equal to 1.143. Alternatively, the median value of the circularity of the positive electrode active material is larger than or equal to 0.7.

A cathode composition for a lithium-ion cell or battery of the general formula: Li.sub.1+xMn.sub.1−xO.sub.2, wherein the composition is in the form of a single phase having a rock salt crystal structure; and the value of x is greater than 0, and equal to or less than 0.3. The compound is also formulated into a positive electrode, or cathode, for use in an electrochemical cell.

The present invention discloses a quaternary cathode material, an cathode and a battery. Particularly, the present invention provides the quaternary cathode material with a chemical structural formula: Li.sub.xNi.sub.a′Co.sub.bMn.sub.c′Al.sub.dM.sub.yO.sub.2, wherein 1x1.05,0<y0.025.0.3a′0.95,0.03b01.0.01c′0.05,0.01d0.005 and a′+b+c′+d=1; M is a dopant selecting from at least one of Zr, Al, B, Ti, Mg, Nb, Ba, Si, P, W, Sr and F. The quaternary cathode material has an α-NaFeO.sub.2 ty

Various embodiments may provide an electromechanical responsive film. The electromechanical responsive film may include a composition including sodium (Na), potassium (K), niobium (Nb) and oxygen (O). The composition may have a formula (Na.sub.xK.sub.y)NbO.sub.3-δ, wherein 0≤x<1, wherein 0≤y<1, and wherein 0<x+y<1. The composition may satisfy at least one condition selected from a group consisting of a first condition of (x+y+4)/2≤(3−δ)≤(x+y+5)/2 and a second condition of 0<δ<1.

A positive electrode active material includes a lithium transition metal oxide having a spinel crystal structure, and a coating layer positioned on the surface of the lithium transition metal oxide, wherein the coating layer has an orthorhombic structure, and includes an oxide represented by Formula 1. A method for producing the positive electrode active material, a positive electrode including the positive electrode active material, and a lithium secondary battery, the positive electrode active material.

Provided is a battery including: a positive electrode containing a positive electrode active material; a negative electrode; and an electrolyte solution containing a nonaqueous solvent. The positive electrode active material contains a compound represented by composition formula (1) below and having a crystal structure belonging to space group FM3-M: Li.sub.xMe.sub.yO.sub.αF.sub.β. (1) Here, Me is one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and C. x, y, α, and β satisfy the following conditions: 1.7≤x≤2.2, 0.8≤y≤1.3, 1≤α≤2.5, and 0.5≤β≤2, respectively. The nonaqueous solvent includes at least one solvent selected from hydrofluoroethers, phosphazenes, phosphates, and perfluoropolyethers.

The present disclosure relates to the technical field of ceramic powder preparation, and discloses a zirconia/titania/cerium oxide doped rare earth tantalum/niobate RETa/NbO.sub.4 ceramic powder and a preparation method thereof. A general chemical formula of the ceramic powder is RE.sub.1-x(Ta/Nb).sub.1-x(Zr/Ce/Ti).sub.2xO.sub.4, 0<x<1, the crystal structure of the ceramic powder is orthorhombic, the lattice space group of the ceramic powder is C222.sub.1, the particle size of the ceramic powder ranges from 10 to 70 μm, and particles of the ceramic powder are spherical. During preparation, the raw materials are ball-milled before a high temperature solid phase reaction, then mixed with a solvent and an organic binder to obtain a slurry C, then centrifuged and atomized to obtain dry pellets, and finally sintered to obtain a zirconia/titanium oxide/cerium oxide doped rare earth tantalum/niobate RETa/NbO.sub.4 ceramic powder, which satisfies the requirements of APS technology for ceramic powders.

Systems and methods are disclosed for a rock-salt structure formed from an electrochemically-driven amorphous-to-crystalline (a-to-c) transformation of nanostructured Nb.sub.2O.sub.5, the rock-salt structure including, upon cycling with lithium ions (Li+), an insertion of lithium ions (Li+) into Nb.sub.2O.sub.5 to form the rock-salt structure (RS—Nb.sub.2O.sub.5).

A crystalline titanium and magnesium compound having an X-ray diffraction pattern having interplanar spacing (d-spacing) values at about 5.94, 3.10, 2.97, 2.10, 1.98, 1.82, and 1.74±0.1 angstroms may be used in protective coatings for metal or metal alloy substrates. The coatings exhibit excellent corrosion resistances and provide corrosion protection equal to or better than typical non-chromate coatings.

A method for producing mesoporous magnesium hydroxide nanoplates involving solvothermal treatment of a solution of a magnesium salt, a base, a glycol, and water is disclosed. The method does not use a surfactant or template in the solvothermal treatment. The method yields mesoporous nanoparticles of magnesium hydroxide having a plate-like morphology with a diameter of 20 nm to 100 nm, a mean pore diameter of 2 to 10 nm, a surface area of 50 to 70 m.sup.2/g, and a type-III nitrogen adsorption-desorption BET isotherm with a H3 hysteresis loop. An antibacterial composition containing the mesoporous magnesium hydroxide nanoplates is also disclosed. A method for reducing nitroaromatic compounds with a reducing agent and the mesoporous magnesium hydroxide nanoplates as a catalyst is also disclosed.