A positive electrode active material for a nonaqueous electrolyte secondary battery includes particles of a lithium-transition metal composite oxide that contains nickel in the composition thereof and has a layered structure. The particles have an average particle size D.sub.SEM based on electron microscopic observation in a range of 1 μm to 7 μm in which a ratio D.sub.50/D.sub.SEM of a 50% particle size D.sub.50 in volume-based cumulative particle size distribution to the average particle size based on electron microscopic observation is in a range of 1 to 4, and a ratio D.sub.90/D.sub.10 of a 90% particle size D.sub.90 to a 10% particle size D.sub.10 in volume-based cumulative particle size distribution is 4 or less.

A positive electrode active material for a nonaqueous electrolyte secondary battery includes particles of a lithium-transition metal composite oxide that contains nickel in the composition thereof and has a layered structure. The particles have an average particle size D.sub.SEM based on electron microscopic observation in a range of 1 μm to 7 μm in which a ratio D.sub.50/D.sub.SEM of a 50% particle size D.sub.50 in volume-based cumulative particle size distribution to the average particle size based on electron microscopic observation is in a range of 1 to 4, and a ratio D.sub.90/D.sub.10 of a 90% particle size D.sub.90 to a 10% particle size D.sub.10 in volume-based cumulative particle size distribution is 4 or less.

A compound of formula I: Na.sub.xNi.sub.0.5-yZn.sub.yMn.sub.0.5-zTi.sub.zO.sub.2 (I), wherein x is a number ranging from 0.7 and 1.1, y is a number superior to 0 and up to 0.1, and z is a number between 0 and 0.5, batteries incorporating the compound and its use in particular as an positive electrode material for Na-ion batteries and cells and a process to obtain such a compound.

A composition of general formula (1): Na.sub.x[Mn.sub.aNi.sub.bCr.sub.c]O.sub.2+y (1), wherein: 0.6≤x≤0.8; −0.1≤y≤0.1; 0.55≤a≤0.7; 0.25≤b≤0.3; c≤0.05; and a+b+c≤1.0, an intermediate product for preparing a composition of general formula (1) and a process of synthesis, wherein the mixed sodium-transition metal oxide of general formula (1) may generally show an essentially or solely P2 structure, and may be used as a positive electrode material for a sodium ion secondary battery.

The present invention provides zinc oxide having excellent infrared blocking ability, high whiteness, and excellent texture during use. The present invention relates to trivalent metal-doped hexagonal plate-shaped zinc oxide having an aspect ratio of 2.5 or greater, the trivalent metal-doped hexagonal plate-shaped zinc oxide having a trivalent metal element content based on the zinc element of 0.15 to 5 mol %, a whiteness of 90 or higher, and a powder spectral reflectance at a wavelength of 1500 nm of 80% or less.

A positive electrode active material for a lithium secondary battery is provided having a secondary particle formed by agglomerating a plurality of polycrystalline primary particles including a lithium composite metal oxide of Chemical Formula 1, wherein an average crystallite size of the primary particle is 180 to 400 nm, a particle size D50 of the primary particle is 1.5 to 3μm, and the primary particle is doped or surface-coated with at least one element M selected from the group consisting Al, Ti, Mg, Zr, Y, Sr, and B in an amount of 3,800 to 7,000 ppm:
Li.sub.a(Ni.sub.xMn.sub.yCo.sub.zA.sub.w)O.sub.2+b   [Chemical Formula 1].

A mixed conductor, a method of preparing the same, and a cathode, a lithium-air battery, and an electrochemical device each including the mixed conductor. The mixed conductor is represented by Formula 1 and having electronic conductivity and ionic conductivity:
Li.sub.xMO.sub.2-δ  Formula 1 wherein, in Formula 1, M is a Group 4 element, a Group 5 element, a Group 6 element, a Group 7 element, a Group 8 element, a Group 10 element, a Group 11 element, a Group 12 element, or a combination thereof, and 0<x<1 and 0≤δ≤1 are satisfied.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

A positive electrode active material for a nonaqueous electrolyte secondary battery includes particles of a lithium-transition metal composite oxide that contains nickel in the composition thereof and has a layered structure. The particles have an average particle size D.sub.SEM based on electron microscopic observation in a range of 1 μm to 7 μm in which a ratio D.sub.50/D.sub.SEM of a 50% particle size D.sub.50 in volume-based cumulative particle size distribution to the average particle size based on electron microscopic observation is in a range of 1 to 4, and a ratio D.sub.90/D.sub.10 of a 90% particle size D.sub.90 to a 10% particle size D.sub.10 in volume-based cumulative particle size distribution is 4 or less.

Provided is a cathode active material for a non-aqueous-electrolyte secondary battery, the cathode active material containing a lithium composite oxide that has a layered structure containing a Li layer and that is represented by general formula LiaNiαAlβCoγMδSrxO.sub.2-w (in the formula, 0.95<a<1.05, 0.85≤α≤0.95, 0<β≤0.08, 0≤γ≤0.1, 0≤δ≤0.15, 0<x≤0.015, 0≤w<0.05, α+β+γ+δ=1, and M is at least one type of element selected from Mn, Fe, Ti, Si, Nb, Zr, Mo, and Zn), wherein the proportions of metal elements present in the Li layer excluding Li are in the range of 1-2.5 mol % with respect to the total molar quantity of metal elements in the lithium composite oxide excluding Li.