A positive-electrode material according to the present disclosure includes a positive-electrode active material and a coating layer covering the positive-electrode active material, wherein the coating layer contains oxygen and lithium, the positive-electrode active material and the coating layer constitute a coated active material, and the ratio Li/O of the lithium content to the oxygen content in a surface layer portion of the coated active material is 0.26 or less based on the atomic ratio.

A covered positive electrode active material includes a particulate positive electrode active material and a solid electrolyte that covers a surface of the positive electrode active material. The solid electrolyte forms a covering layer. The covering layer is formed such that recessed portions of the surface of the positive electrode active material are filled with the solid electrolyte. Protruding portions of the surface of the positive electrode active material are exposed on a surface of the covered positive electrode active material. A degree of unevenness of a group of particles of the positive electrode active material is defined as ζ.sub.1, a degree of unevenness of a group of particles of the covered positive electrode active material is defined as ζ.sub.2, and a degree of change in unevenness R defined by formula (2) below is greater than or equal to 1.1.

R=ζ.sub.2/ζ.sub.1   (2)

A nickel-based active material for a lithium secondary battery, a method of preparing the nickel-based active material, and a lithium secondary battery including a positive electrode including the nickel-based active material, the nickel-based active material comprising a secondary particle having an outer portion with a radially arranged structure and an inner portion with an irregular porous structure, wherein the inner portion of the secondary particle has a larger pore size than the outer portion of the secondary particle.

The production method is a method for producing a positive electrode active material for a lithium ion secondary battery which contains at least nickel and lithium, the method including: a firing process in which a mixture of a nickel compound powder and a lithium compound powder is fired; and a water washing process in which a lithium-nickel composite oxide powder obtained in the firing process is washed with water, wherein the firing process is performed under conditions such that a value obtained by dividing a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder after the washing with water by a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder before the washing with water exceeds 0.95.

A cathode material, containing a crystal with a superlattice structure, is provided. A chemical formula of the crystal is xLi.sub.2MO.sub.3.(1-x)LiNi.sub.aCo.sub.bMn.sub.(1-a-b)O.sub.2, where 0<x≤0.1, 0.8≤a<1, b≤0.1, and M is selected from one or more of Mn, Co, and Ni. A preparation method of the cathode material and a battery or a capacitor containing the cathode material are also provided.

A gradient doped cobalt-free positive electrode material and a preparation method therefor, a lithium-ion battery positive electrode, and a lithium battery. The positive electrode material consists of LiNi.sub.xMn.sub.yA.sub.zO.sub.2. The content of element A in the positive electrode material decreases in a direction from a surface layer of the positive electrode material to the center, and A is one or more of Al, Zr, Ti, B, and W. The preparation method is easy to implement, simplifies roasting condition requirements, and provides a cobalt-free positive electrode material having good cycle performance.

A cobalt-free positive electrode material and a preparation method therefor, a lithium ion battery positive electrode, and a lithium ion battery, relating to the technical field of lithium ion batteries. The positive electrode material comprises a core and a shell covering the core, the core being a cobalt-free positive electrode material, the chemical formula of the core being LiNi.sub.xMn.sub.yO.sub.2, wherein 0.55≤x≤0.95 and 0.05≤y≤0.45, and the shell is a coating agent and carbon. The present method can improve the dispersibility of the cobalt-free positive electrode material during the coating process, and can also improve the conductivity of the cobalt-free positive electrode material.

The present invention relates to a lithium metal composite oxide powder having a layered structure, and comprising at least Li, Ni, and an element X, wherein: said element X is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti. Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P; and the lithium metal composite oxide powder satisfies requirements (1), (2), and (3): (1) an angle of difference (θ1- θ2) calculated from an angle of repose (θ1) and an angle of fall (θ2) is 15° or less, wherein the angle of repose (θ1) is an angle of slope of the lithium metal composite oxide powder piled on a measurement table, and the angle of fall (θ2) is an angle of slope measured after application of a predetermined impact force to the measurement table; (2) an average primary particle diameter is 1 .Math.m or more; and (3) an amount of water contained in the lithium metal composite oxide powder is 1000 ppm or less.

Provided in the present disclosure are a positive electrode material used for a lithium ion battery. The positive electrode material comprises substrate particles, a first cladding layer that covers the substrate particles, and a second cladding layer that covers the first cladding layer; the substrate particles contain LiNi.sub.xMn.sub.y Co.sub.zM.sub.1-x-y-zO.sub.2; the first cladding layer contains lithium cobalt oxide; and the second cladding layer contains an oxide of a transition metal.

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.Math.H.sub.2O in a mortar and then calcined at a high temperature to obtain an MOF-coated monocrystal ternary positive electrode material.