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.

A cathode active material for a lithium secondary battery according to embodiments of the present disclosure includes a lithium-transition metal oxide including a transition metal including nickel (Ni). A molar ratio of lithium to elements except for lithium and oxygen in the lithium-transition metal oxide is 1.04 to 1.08, and a molar fraction of cobalt (Co) in the transition metal is 0.05 or less. A lithium secondary battery including the cathode active material for a lithium secondary battery and having improved structural stability and charge/discharge efficiency is provided.

The present disclosure relates to: a positive electrode NCM-based active material in which a crystallite size is 460 or more; a positive electrode including the positive electrode NCM-based active material; and a battery including the positive electrode. According to the present disclosure, there are provided: the positive electrode NCM (nickel-cobalt-manganese)-based active material that can exhibit an improved low-temperature low-SOC output property as well as high thermal stability; the positive electrode including the positive electrode NCM-based active material; and the battery including the positive electrode.

The present disclosure relates to: a positive electrode NCM-based active material in which a crystallite size is 460 or more; a positive electrode including the positive electrode NCM-based active material; and a battery including the positive electrode. According to the present disclosure, there are provided: the positive electrode NCM (nickel-cobalt-manganese)-based active material that can exhibit an improved low-temperature low-SOC output property as well as high thermal stability; the positive electrode including the positive electrode NCM-based active material; and the battery including the positive electrode.

A positive electrode active material for rechargeable lithium batteries includes: a first positive electrode active material including a first lithium nickel-based composite oxide and being in a form of secondary particles having an average particle diameter (D.sub.50) of about 10 m to about 25 m; a second positive electrode active material including a second lithium nickel-based composite oxide and being in a form of secondary particles having an average particle diameter (D.sub.50) of about 0.5 m to about 8 m; and a third positive electrode active material including a third lithium nickel-based composite oxide and being in a form of secondary particles including a plurality of primary particles, wherein an average particle diameter (D.sub.50) of the secondary particles is about 0.5 m to about 8 m, and the primary particles constituting the secondary particles of the third positive electrode active material are needle-shaped.

A positive electrode active material for rechargeable lithium batteries includes: a first positive electrode active material including a first lithium nickel-based composite oxide and being in a form of secondary particles having an average particle diameter (D.sub.50) of about 10 m to about 25 m; a second positive electrode active material including a second lithium nickel-based composite oxide and being in a form of secondary particles having an average particle diameter (D.sub.50) of about 0.5 m to about 8 m; and a third positive electrode active material including a third lithium nickel-based composite oxide and being in a form of secondary particles including a plurality of primary particles, wherein an average particle diameter (D.sub.50) of the secondary particles is about 0.5 m to about 8 m, and the primary particles constituting the secondary particles of the third positive electrode active material are needle-shaped.

A method of preparing a positive electrode active material, and a rechargeable lithium battery including a positive electrode active material prepared therefrom are provided. The method includes adding lithium carbonate, nickel carbonate, and cobalt carbonate to an aqueous solvent and mixing the lithium carbonate, the nickel carbonate, the cobalt carbonate, and the aqueous solvent to prepare a raw material mixture, wet-pulverizing the raw material mixture, spray-drying the pulverized raw material mixture to obtain a positive electrode active material precursor mixture, and subjecting the positive electrode active material precursor mixture to heat treatment to obtain a positive electrode active material in a form of single particles and including lithium nickel-cobalt-based composite oxide.

A method of preparing a positive electrode active material, and a rechargeable lithium battery including a positive electrode active material prepared therefrom are provided, the method including adding lithium hydroxide, nickel sulfate, cobalt sulfate, and ammonium carbonate to an aqueous solvent and mixing them to prepare a raw material mixture, wet-pulverizing the raw material mixture, spray-drying the pulverized material to obtain a positive electrode active material precursor mixture, and subjecting the positive electrode active material precursor mixture to heat treatment to obtain a positive electrode active material in a form of a single particle and including lithium nickel-cobalt-based composite oxide.

A method of preparing a positive electrode active material, and a rechargeable lithium battery including a positive electrode active material prepared therefrom are provided, the method including adding lithium hydroxide, nickel sulfate, cobalt sulfate, and ammonium carbonate to an aqueous solvent and mixing them to prepare a raw material mixture, wet-pulverizing the raw material mixture, spray-drying the pulverized material to obtain a positive electrode active material precursor mixture, and subjecting the positive electrode active material precursor mixture to heat treatment to obtain a positive electrode active material in a form of a single particle and including lithium nickel-cobalt-based composite oxide.