A cathode active material for a lithium secondary battery has a structure of a lithium transition metal oxide. A ratio of a crystallite size of a (003) plane to a crystallite size of a (110) plane measured by an X-ray diffraction (XRD) analysis is in a range from 0.7 to 2.0, and a ratio of the crystallite size of the (003) plane to a crystallite size of a (104) plane measured by the XRD analysis is in a range from 0.7 to 2.0. A cathode for a lithium secondary battery and a lithium secondary battery include the cathode active material for a lithium secondary battery.

A cathode active material for a lithium secondary battery has a structure of a lithium transition metal oxide. A ratio of a crystallite size of a (003) plane to a crystallite size of a (110) plane measured by an X-ray diffraction (XRD) analysis is in a range from 0.7 to 2.0, and a ratio of the crystallite size of the (003) plane to a crystallite size of a (104) plane measured by the XRD analysis is in a range from 0.7 to 2.0. A cathode for a lithium secondary battery and a lithium secondary battery include the cathode active material for a lithium secondary battery.

The present invention may provide a cathode active material that exhibits excellent structural stability and lifespan retention rate even in a high-temperature environment where a battery is operating. In addition, the present invention may provide a cathode including an active material layer containing the cathode active material and provide a battery cell including the cathode. In addition, the present invention is aimed at providing a battery cell assembly including the battery cell. In addition, the present invention may provide an electric device including one or more selected from the group consisting of the battery cell and the battery cell assembly.

The present invention may provide a cathode active material that exhibits excellent structural stability and lifespan retention rate even in a high-temperature environment where a battery is operating. In addition, the present invention may provide a cathode including an active material layer containing the cathode active material and provide a battery cell including the cathode. In addition, the present invention is aimed at providing a battery cell assembly including the battery cell. In addition, the present invention may provide an electric device including one or more selected from the group consisting of the battery cell and the battery cell assembly.

A positive electrode material, a preparation method of same, a positive electrode plate, a secondary battery, and an electrical device are described. The positive electrode material includes a ternary positive electrode substrate and optionally a coating layer. The coating layer coats a surface of the ternary positive electrode substrate. The ternary positive electrode substrate includes Li, Ni, Al, and an M element. The M element includes a combination of one or more of Mn, Co, Ti, Zr, W, Nb, Mo, Si, Mg, B, Cr, or Ta. A volume-based particle size distribution curve of the positive electrode material is a bimodal curve.

A positive electrode material, a preparation method of same, a positive electrode plate, a secondary battery, and an electrical device are described. The positive electrode material includes a ternary positive electrode substrate and optionally a coating layer. The coating layer coats a surface of the ternary positive electrode substrate. The ternary positive electrode substrate includes Li, Ni, Al, and an M element. The M element includes a combination of one or more of Mn, Co, Ti, Zr, W, Nb, Mo, Si, Mg, B, Cr, or Ta. A volume-based particle size distribution curve of the positive electrode material is a bimodal curve.

Provided is a positive electrode active material including core particles including zirconium-doped layered lithium nickel-manganese-aluminum-based composite oxide, wherein the core particle is a secondary particle formed by agglomerating a plurality of primary particles, an average particle diameter (D50) of the secondary particles is about 10 m to about 25 m, and in the zirconium-doped layered lithium nickel-manganese-aluminum-based composite oxide, a zirconium content is about 0.2 mol % to about 0.8 mol % based on 100 mol % of a total metal excluding lithium. The positive electrode active material according to some embodiments may maximize capacity, while minimizing a production cost, to ensure long cycle-life characteristics and improve high-voltage characteristics and high-temperature characteristics. If the positive electrode active material is applied to a rechargeable lithium battery, high initial charge/discharge capacity and efficiency may be achieved under high-voltage operating conditions, and long cycle-life characteristics may be realized under high-voltage and high-temperature conditions.

Provided is a positive electrode active material including core particles including zirconium-doped layered lithium nickel-manganese-aluminum-based composite oxide, wherein the core particle is a secondary particle formed by agglomerating a plurality of primary particles, an average particle diameter (D50) of the secondary particles is about 10 m to about 25 m, and in the zirconium-doped layered lithium nickel-manganese-aluminum-based composite oxide, a zirconium content is about 0.2 mol % to about 0.8 mol % based on 100 mol % of a total metal excluding lithium. The positive electrode active material according to some embodiments may maximize capacity, while minimizing a production cost, to ensure long cycle-life characteristics and improve high-voltage characteristics and high-temperature characteristics. If the positive electrode active material is applied to a rechargeable lithium battery, high initial charge/discharge capacity and efficiency may be achieved under high-voltage operating conditions, and long cycle-life characteristics may be realized under high-voltage and high-temperature conditions.

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 includes a lithium composite metal oxide including nickel, cobalt, manganese, and aluminum. The positive electrode active material includes 85 mol % to 97 mol % of nickel, and 2 mol % to 5 mol % of cobalt, with respect to the total number of moles of metals other than lithium, and satisfies Expression (1): 0.25I.sub.550/I.sub.7000.4. In Expression (1), I.sub.700 and I.sub.550 are respectively a maximum value of a peak intensity appearing in a range of 600 ppm to 800 ppm and a maximum value of a peak intensity appearing in a range of 450 ppm to 650 ppm when a spectral analysis (peak deconvolution) is performed on a 1D NMR center band spectrum extracted from a 2D .sup.7Li Magic Angle Turning Phase Adjusted Spinning Sideband (MATPASS) NMR spectrum. A positive electrode and a lithium secondary battery are also included