A positive electrode active material to be used in a non-aqueous electrolyte secondary battery and containing a lithium transition metal compound which contains Ni in a proportion constituting 80-94 mol %, inclusive, relative to the total mole number of the metal elements other than Li, and also contains Nb in a proportion constituting 0.1-0.6 mol %, inclusive, relative thereto, the positive electrode active material being characterized in that the Nb amount n1 in a first sample solution obtained by adding 0.2 g of the lithium transition metal compound to a hydrochloric acid aqueous solution comprising 5 mL of pure water/5 mL of 35% hydrochloric acid, and the Nb amount n2 in a second sample solution obtained by immersing a filter used to filter the first sample solution in a fluonitric acid comprising 5 mL of 46% hydrofluoric acid/5 mL of 63% nitric acid satisfy the condition of 50%≤n1/(n1+n2)<75% when converted to molar quantities.

A positive electrode active material includes lithium transition metal-containing composite oxide particles containing an additive element M1 and includes a coating layer formed of a metal composite oxide of Li and a metal element M2 on a part of a surface of the particles. The particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m.sup.2/g, a tap density of 1.0 to 2.0 g/cm.sup.3, and an oil absorption amount of 30 to 60 ml/100 g. For each of a plurality of primary particles having a primary particle size within a range of 0.1 to 1.0 μm among the primary particles, a coefficient of variation of the concentration of M1 is 1.5 or less, and the amount of M2 is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.

A layered double hydroxide is represented by the following formula (I): Ni.sup.2+.sub.1−(x+y+z)Fe.sup.3+.sub.xV.sup.3+.sub.yCo.sup.3+.sub.z(OH).sub.2A.sup.n−.sub.(x+y+z)/n.Math.mH.sub.2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.

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.

Disclosed is a lithium complex oxide and method of manufacturing the same, more particularly, a lithium complex oxide effective in improving the characteristics of capacity, resistance, and lifetime with reduced residual lithium and with different interplanar distances of crystalline structure between a primary particle locating in an internal part of secondary particle and a primary particle locating on the surface part of the secondary particle, and a method of preparing the same.

A process for making a mixed metal oxide, may involve: (a) providing a hydroxide or oxyhydroxide of TM with an average particle diameter (D50) in the range of from 0.1 μm to 5 mm; (b) subjecting the hydroxide or oxyhydroxide of TM to a stream of gas with a temperature in the range of from 150 to 2000° C., wherein TM contains nickel and at least one further transition metal selected from cobalt and manganese.

The present invention provides a composite oxide that can achieve a high low-temperature output characteristic, a method for manufacturing the same, and a positive electrode active material in which the generation of soluble lithium is suppressed and a problem of gelation is not caused during the paste preparation. A positive electrode active material for non-aqueous electrolyte secondary batteries, including a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or a lithium-metal composite oxide powder including both the primary particles and the secondary particle. The secondary particle has a porous structure inside as a main inside structure, the slurry pH is 11.5 or less, the soluble lithium content rate is 0.5 [% by mass] or less, the specific surface area is 3.0 to 4.0 [m.sup.2/g], and the porosity is more than 50 to 80 [%].

The present invention provides a method of preparing an MOF-coated monocrystal ternary positive electrode material. Firstly, a solution A of nickel, cobalt and manganese metal salts, an ammonia complexing agent solution and a caustic soda liquid are added to a reactor for reaction to obtain a precursor core; then, an organic carboxylate is dissolved in an amount of an organic solvent to obtain a solution B; the solution B and a manganese metal salt solution with a given concentration are added to the reactor and aged to obtain an MOF-coated core-shell structure precursor; the core-shell structure precursor is pre-sintered at a low temperature to obtain a nickel-cobalt-manganese oxide with monocrystal structure; the nickel-cobalt-manganese oxide with monocrystal structure is uniformly mixed with LiOH.H.sub.2O in a mortar and then calcined at a high temperature to obtain an MOF-coated monocrystal ternary positive electrode material.

Provided herein are processes for producing positive electrode active substance particles for non-aqueous electrolyte secondary batteries which is excellent in life characteristics of a battery with respect to a repeated charging and discharging performance thereof, as well as a non-aqueous electrolyte secondary battery. In particular, provided herein are processes for producing a positive electrode active substance for non-aqueous electrolyte secondary batteries comprising lithium transition metal layered oxide having a composition represented by the formula: Li.sub.a(Ni.sub.xCo.sub.yMn.sub.1-x-y)O.sub.2 wherein a is 1.0≤a≤1.15; x is 0<x<1; and y is 0<y<1, in which the positive electrode active substance is in the form of secondary particles formed by aggregating primary particles thereof, and a coefficient of variation of a compositional ratio: Li/Me wherein Me is a sum of Ni, Co and Mn as measured on a section of the secondary particle is not more than 25%.

A positive active material for a rechargeable lithium battery includes a lithium nickel-based composite oxide including a secondary particle in which a plurality of plate-shaped primary particles are agglomerated; and a lithium manganese composite oxide having at least two crystal lattice structures, wherein the secondary particle has a regular array structure in which (003) planes of the primary particles are oriented in a vertical direction with respect to the surface of the secondary particle.