Abstract: The present invention provides a positive electrode active material for a secondary battery, the positive electrode active material being a primary particle having a monolithic structure that includes a lithium composite metal oxide of Formula 1 below, wherein the primary particle has an average particle size (D50) of 2 ?m to 20 ?m and a Brunauer-Emmett-Teller (BET) specific surface area of 0.15 m2/g to 1.9 m2/g, and a secondary battery including the same.

Abstract: The present invention provides a positive electrode active material for a secondary battery, the positive electrode active material being a secondary particle that includes a primary particle having a rectangular parallelepiped shape, the rectangular parallelepiped having at least one portion of vertices and edges formed in a round shape that is convex outward, wherein 1% to 40% of a total surface area of the secondary particle has open porosity, and the primary particle includes a lithium composite metal oxide of Formula 1 herein so that intercalation and deintercalation of lithium are facilitated, elution of an active material-constituting metal element is suppressed, and excellent structural stability is exhibited, thereby decreasing resistance and improving output and lifespan characteristics when applied to a battery, and a secondary battery comprising the same.

Abstract: The present invention provides a positive electrode active material for a secondary battery, the positive electrode active material including a lithium composite metal oxide particle represented by Formula 1 below, and a secondary battery including the same. LiaNi1?x?yCoxM1yM2zM3wO2??[Formula 1] In Formula 1, M1 is a metal element whose surface energy (?Esurf) calculated by Equation 1 below is ?0.5 eV or higher, M2 is a metal element whose surface energy (?Esurf) calculated by Equation 1 below is ?1.5 eV or higher and less than ?0.5 eV, M3 is a metal element whose surface energy (?Esurf) calculated by Equation 1 below is less than ?1.5 eV, and 1.0?a?1.5, 0<x?0.5, 0<z?0.05, 0.002?w?0.1, 0<x+y?0.7.

Abstract: The present invention provides a positive electrode active material for a secondary battery and a secondary battery including the same, which includes a core; a shell located to surround the core; and a buffer layer located between the core and the shell, and including a three-dimensional network structure connecting the core and the shell and a pore, in which the core, the shell, and the three-dimensional network structure in the buffer layer each independently include a lithium nickel-manganese-cobalt-based composite metal oxide, and the positive electrode active material has a BET specific surface area of 0.2 m2/g to 0.5 m2/g, a porosity of 30 vol % or less, and an average particle size (D50) of 8 ?m to 15 ?m.

Abstract: Provided are a positive electrode active material having a concentration gradient in which concentrations of nickel and manganese are gradually changed from a center of a particle to a surface thereof, and a peak appears at 235° C. or more when heat flow of the positive electrode active material is measured by differential scanning calorimetry, a method of preparing the positive electrode active material, and a lithium secondary battery including the positive electrode active material.

Abstract: The present invention relates to a positive electrode active material for a secondary battery and a secondary battery including the same, wherein the positive electrode active material includes a core, a shell disposed to surround the core, and a buffer layer which is disposed between the core and the shell and includes pores and a three-dimensional network structure connecting the core and the shell, wherein the core, the shell, and the three-dimensional network structure of the buffer layer each independently includes a polycrystalline lithium composite metal oxide of Formula 1 including a plurality of grains, and the grains have an average grain diameter of 50 nm to 150 nm.

Abstract: The present invention provides a positive electrode active material for a secondary battery, which includes a core, a shell disposed to surround the core, and a buffer layer which is disposed between the core and the shell and includes pores and a three-dimensional network structure connecting the core and the shell, wherein, the core, the shell, and the three-dimensional network structure of the buffer layer each independently include a lithium nickel manganese cobalt-based composite metal oxide and at least one metallic element of the nickel, the manganese, and the cobalt has a concentration gradient that gradually changes in any one region of the core, the shell, and the entire positive electrode active material.