The positive electrode active substance for a lithium secondary battery comprises a lithium nickel manganese cobalt composite oxide particle represented by the following general formula (1): Li.sub.xNi.sub.yMn.sub.zCo.sub.tM.sub.pO.sub.1+x. M denotes one or two or more metal elements selected from Al, Zr, Cu, Fe, Sr, Ca, V, Mo, Bi, Nb, Si, Zn, Ga, Ge, Sn, Ba, W, Na and K; and x denotes 0.98x1.20, y denotes 0.30y<1.00, z denotes 0<z0.50, t denotes 0<t0.50, p denotes 0p0.05, and y+z+t+p=1; and being made to contain Ti as solid solution. The lithium nickel manganese cobalt composite oxide particle exhibits a single phase in X-ray diffractometry.

The positive electrode active substance for a lithium secondary battery comprises a lithium nickel manganese cobalt composite oxide particle represented by the following general formula (1): Li.sub.xNi.sub.yMn.sub.zCo.sub.tM.sub.pO.sub.1+x. M denotes one or two or more metal elements selected from Al, Zr, Cu, Fe, Sr, Ca, V, Mo, Bi, Nb, Si, Zn, Ga, Ge, Sn, Ba, W, Na and K; and x denotes 0.98x1.20, y denotes 0.30y<1.00, z denotes 0<z0.50, t denotes 0<t0.50, p denotes 0p0.05, and y+z+t+p=1; and being made to contain Ti as solid solution. The lithium nickel manganese cobalt composite oxide particle exhibits a single phase in X-ray diffractometry.

Improved methods for preparing lithium nickel manganese cobalt oxide particulate are disclosed for use in lithium batteries and other applications. The methods involve triturating and heating steps that produce single-phase rock-salt precursor particulate from which the lithium nickel manganese cobalt oxide particulate can be readily prepared. Advantageously, the triturating step can involve dry, lower energy procedures that take less time to prepare precursor particulate than previous methods. The methods therefore can be simpler, faster, and can reduce contamination in the product. Also disclosed is the optional use of novel biphasic precursor particulate in the preparation methods.

Improved methods for preparing lithium nickel manganese cobalt oxide particulate are disclosed for use in lithium batteries and other applications. The methods involve triturating and heating steps that produce single-phase rock-salt precursor particulate from which the lithium nickel manganese cobalt oxide particulate can be readily prepared. Advantageously, the triturating step can involve dry, lower energy procedures that take less time to prepare precursor particulate than previous methods. The methods therefore can be simpler, faster, and can reduce contamination in the product. Also disclosed is the optional use of novel biphasic precursor particulate in the preparation methods.

Provided is a cathode material and a preparation method therefor, and a secondary battery. The cathode material is a lithium nickel cobalt oxide composite oxide. In an XRD pattern of the cathode material, a characteristic peak of a crystal face (104) includes a (104)K1 diffraction peak and a (104)K2 diffraction peak after peak splitting, a separation value between the (104)K1 diffraction peak and the (104)K2 diffraction peak is a, and 0.72.0. The cathode material has suitable particle size, good particle strength and sufficient internal defects, which are conducive to reducing the phenomenon of polarization of the cathode material, such that the secondary battery based on the cathode material has both better cycle stability and rate performance.

Provided is a cathode material and a preparation method therefor, and a secondary battery. The cathode material is a lithium nickel cobalt oxide composite oxide. In an XRD pattern of the cathode material, a characteristic peak of a crystal face (104) includes a (104)K1 diffraction peak and a (104)K2 diffraction peak after peak splitting, a separation value between the (104)K1 diffraction peak and the (104)K2 diffraction peak is a, and 0.72.0. The cathode material has suitable particle size, good particle strength and sufficient internal defects, which are conducive to reducing the phenomenon of polarization of the cathode material, such that the secondary battery based on the cathode material has both better cycle stability and rate performance.

There is provided a cathode active material for a lithium ion secondary battery containing a lithium transition metal composite oxide as a main component, wherein the lithium transition metal composite oxide is in a form of a particle having an outer layer on a surface of the particle, the lithium transition metal composite oxide is represented by the following Formula (1):

##STR00001## wherein m, w, x, y, and z are respectively in ranges of 1.00m1.04, 0.47<w<0.59, 0.40x<0.50, 0<y0.04, and 0z<0.04, and xw, and m+w+x+y+z=2, and a ratio of the number of Mn atoms to the number of Ni atoms (Mn/Ni ratio) in the outer layer is 1.0 or more and 1.5 or less.

There is provided a cathode active material for a lithium ion secondary battery containing a lithium transition metal composite oxide as a main component, wherein the lithium transition metal composite oxide is in a form of a particle having an outer layer on a surface of the particle, the lithium transition metal composite oxide is represented by the following Formula (1):

##STR00001## wherein m, w, x, y, and z are respectively in ranges of 1.00m1.04, 0.47<w<0.59, 0.40x<0.50, 0<y0.04, and 0z<0.04, and xw, and m+w+x+y+z=2, and a ratio of the number of Mn atoms to the number of Ni atoms (Mn/Ni ratio) in the outer layer is 1.0 or more and 1.5 or less.

The present disclosure relates to the technical field of lithium-ion batteries, and particularly, to a multi-element cathode material, a preparation method thereof, a positive electrode plate, and a lithium-ion battery. The multi-electrode material is composed of secondary particles agglomerated by primary particles. A ratio of a total cross-sectional area of the primary particles with more than 5 grain boundaries to a cross-sectional area of the secondary particles is greater than or equal to 3:4. A porosity on a cross-section of the secondary particles is less than or equal to 2%. A grain boundary is a contour line of an interface between the primary particles with the same structure but different orientations on the cross-section of the secondary particles and a length of the grain boundary is greater than or equal to 0.1 m.

The present disclosure relates to the technical field of lithium-ion batteries, and particularly, to a multi-element cathode material, a preparation method thereof, a positive electrode plate, and a lithium-ion battery. The multi-electrode material is composed of secondary particles agglomerated by primary particles. A ratio of a total cross-sectional area of the primary particles with more than 5 grain boundaries to a cross-sectional area of the secondary particles is greater than or equal to 3:4. A porosity on a cross-section of the secondary particles is less than or equal to 2%. A grain boundary is a contour line of an interface between the primary particles with the same structure but different orientations on the cross-section of the secondary particles and a length of the grain boundary is greater than or equal to 0.1 m.