A high-voltage low-cobalt ternary positive electrode material has a general formula Li.sub.aNi.sub.bCo.sub.cMn.sub.dO.sub.2, where 0.97a1.1, 0.5b0.76, 0c0.1, 0.24d0.5, b+c+d=1, and c<0.35d. Compared with the prior art, the positive electrode material can be used at a higher voltage compared to other ternary positive electrode materials which have the same nickel content as the positive electrode material, such that the energy density is increased, and because the positive electrode material has a smaller change in size, the cracking and powdering of the positive electrode material are avoided, the service life of the material is prolonged, and the safety performance of the material is improved.

A positive active material has a chemical formula of Li.sub.1+a[Ni.sub.xCo.sub.yMn.sub.zM1.sub.bM2.sub.c]O.sub.2, where, 0.05<a<0.5, x<1, 0y<, 0z<, 0<b<0.1, 0<c<0.1, x+y+z+b+c=1, M1 is one or more elements from Mo, Zr, W, Sb, Nb, Te or Ga, and M2 is one or more elements from Mg, Al, Ca or Ti. The positive active material includes a lithium-rich layer extending from particle surface to interior of the particle, and in a cross section passing through the geometric center of a single particle of the positive active material, a ratio of an average Li element content per unit area in the lithium-rich layer to an average Li element content per unit area in a non-lithium-rich layer is (>1 to 1.5):1.

A positive electrode active material powder includes particles (A) composed of a positive electrode active material. The particles (A) include primary particles (A1) and secondary particles (A2) formed by sintering together primary particles (A1). In a scanning micrograph of a field of view in which 50 or more of the particles (A) are contained, the ratio of coarse secondary particles is 45 number % or less with respect to the total number of the particles (A) in the field of view. The coarse secondary particles are, among the secondary particles (A2), secondary particles (A2) formed by sintering together five or more of the primary particles (A1). The ratio of microparticles is 1.5 number % or less with respect to the total number of the particles (A) in the field of view. The microparticles are, among the particles (A), particles (A) having a circle-equivalent diameter of 0.8 m or less.

A positive electrode active material powder includes particles (A) composed of a positive electrode active material. The particles (A) include primary particles (A1) and secondary particles (A2) formed by sintering together primary particles (A1). In a scanning micrograph of a field of view in which 50 or more of the particles (A) are contained, the ratio of coarse secondary particles is 45 number % or less with respect to the total number of the particles (A) in the field of view. The coarse secondary particles are, among the secondary particles (A2), secondary particles (A2) formed by sintering together five or more of the primary particles (A1). The ratio of microparticles is 1.5 number % or less with respect to the total number of the particles (A) in the field of view. The microparticles are, among the particles (A), particles (A) having a circle-equivalent diameter of 0.8 m or less.

Disclosed herein are a ternary precursor with a high tap density and a method for preparing same. The method comprises the following steps: (1) adding a silicon dioxide emulsion into an alkaline substrate solution to give a mixed solution; (2) adding a mixed nickel-cobalt-manganese salt solution, a precipitant, a complexing agent, and a surfactant; (3) conducting solid-liquid separation to give a solid material, and drying and crushing to give a crushed material; (4) mixing the crushed material with the alkaline substrate solution and the surfactant; (5) repeating step (2); and (6) conducting solid-liquid separation to give a solid material, and washing and drying the solid material to give the ternary precursor with a high tap density. The precursor particle prepared according to the method has a higher tap density, and can provide excellent cycle performance for the positive electrode material.

Disclosed herein are a ternary precursor with a high tap density and a method for preparing same. The method comprises the following steps: (1) adding a silicon dioxide emulsion into an alkaline substrate solution to give a mixed solution; (2) adding a mixed nickel-cobalt-manganese salt solution, a precipitant, a complexing agent, and a surfactant; (3) conducting solid-liquid separation to give a solid material, and drying and crushing to give a crushed material; (4) mixing the crushed material with the alkaline substrate solution and the surfactant; (5) repeating step (2); and (6) conducting solid-liquid separation to give a solid material, and washing and drying the solid material to give the ternary precursor with a high tap density. The precursor particle prepared according to the method has a higher tap density, and can provide excellent cycle performance for the positive electrode material.

Disclosed are positive electrode active materials, methods of fabricating the same, and rechargeable lithium batteries including the same. The positive electrode active material includes a first particle including a first lithium composite oxide. The first particle includes a first primary particle that extends in a radial direction from a center of the first particle toward a surface of the first particle, and a second primary particle on the surface. An aspect ratio of the first primary particle is about 2 to about 15. An aspect ratio of the second primary particle is about 0.7 to about 3.

Disclosed is a method for continuously preparing mixed hydroxide precipitate from a laterite nickel ore by hydrometallurgy. Primary-precipitated mixed hydroxide precipitate particles are used as crystal nuclei, by controlling precipitation process conditions, the quantity of the crystal nuclei, and reaction time of the crystal nuclei, primary mixed hydroxide precipitate crystal nuclei gradually grow, and crystal forms become larger. By controlling the number of cycles, a proportion of returned seed crystals, and a homogenization ratio with precipitants, mixed hydroxide precipitate particles with narrow particle size distribution, dense particles, and better sedimentation effect are obtained, thereby reducing a moisture content of mixed hydroxide precipitate. The preparation method in this disclosure plays a certain guiding role in practical production and has good application prospects.

A metal composite compound is provided with which a lithium secondary battery having high initial charge and discharge efficiency can be produced. A metal composite compound containing at least Ni, in which in the metal composite compound, when in a differential pore volume distribution determined by a Barrett-Joyner-Halenda method from a nitrogen gas adsorption isotherm, an integrated area of a region where a pore diameter is 1 nm or more and 50 nm or less is A, and an integrated area of a region where the pore diameter is more than 50 nm and 200 nm or less is B, A/B is 0.05 or more and less than 1.5.

Provided is a nickel-containing hydroxide coated with cobalt, having a coating layer containing cobalt oxyhydroxide formed on a nickel-containing hydroxide, in which an average circularity of particles having particle diameters equal to or more than a particle diameter at a cumulative volume percentage of 50% (D50) within a range of 0.900 or more and 0.990 or less.