KR-20260068030-A - CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

KR20260068030AKR 20260068030 AKR20260068030 AKR 20260068030AKR-20260068030-A

Abstract

The present embodiments relate to a positive electrode active material for a lithium secondary battery and a lithium secondary battery including the same. A positive electrode active material for a lithium secondary battery according to one embodiment comprises a nickel-containing metal oxide in the form of a single particle; a doping element doped into the nickel-containing metal oxide; and a coating layer located on the surface of the nickel-containing metal oxide, wherein the coating layer comprises two or more coating elements, and the doping elements comprise Al, Y, and Zr, and the content of Y may be in the range of 400 ppm to 2,000 ppm based on the total weight of the nickel-containing metal oxide on which the coating layer is formed.

Inventors

이수빈
명민훈
심성근
이승원
최권영

Assignees

(주)포스코퓨처엠

Dates

Publication Date: 20260513
Application Date: 20260413

Claims (14)

Nickel-containing metal oxide in single-particle form; A doping element doped into the nickel-containing metal oxide; and It includes a coating layer located on the surface of the nickel-containing metal oxide, and The above coating layer comprises two or more coating elements, and The above doping elements include Al, Y, and Zr, and A positive electrode active material for a lithium secondary battery, wherein the content of Y is in the range of 400 ppm to 2,000 ppm based on the total weight of the nickel-containing metal oxide on which the coating layer is formed.
In paragraph 1, The above coating layer is a positive electrode active material for a lithium secondary battery comprising Co and Al.
In paragraph 2, A positive electrode active material for a lithium secondary battery, wherein the content of Co in the positive electrode active material having the coating layer formed thereon is in the range of 0.035 moles to 0.08 moles based on 1 mole of the total amount of transition metals contained in the nickel-containing metal oxide having the coating layer formed thereon.
In paragraph 1, A positive electrode active material for a lithium secondary battery, wherein the content of Al in the positive electrode active material having the coating layer formed thereon is in the range of 0.001 mole to 0.015 mole based on 1 mole of the total amount of transition metal contained in the nickel-containing metal oxide having the coating layer formed thereon.
In paragraph 1, A positive electrode active material for a lithium secondary battery, wherein the content of Zr is in the range of 1,200 ppm to 2,800 ppm based on the total weight of the nickel-containing metal oxide on which the coating layer is formed.
In paragraph 1, A positive electrode active material for a lithium secondary battery, wherein the nickel content is 0.8 moles or more based on 1 mole of the total transition metal contained in the nickel-containing metal oxide on which the coating layer is formed.
In paragraph 6, The above nickel-containing metal oxide further comprises manganese, and A positive electrode active material for a lithium secondary battery, wherein the manganese content is 0.15 moles or less based on 1 mole of the total amount of transition metals contained in the nickel-containing metal oxide on which the coating layer is formed.
In paragraph 1, The nickel-containing metal oxide with the above-mentioned coating layer is a positive electrode active material for a lithium secondary battery represented by the following chemical formula 1: [Chemical Formula 1] Li a [Ni x Co y Mn z M1 w1 M2 w2 ]O 2 In the above chemical formula 1, 0.8≤a≤1.2, 0.8≤x≤0.99, 0<y≤0.06, 0<z≤0.14, 0<w1≤0.1, 0≤w2≤0.1, x+y+z+w1+w2=1, M1 is Al, Y and Zr, and M2 includes one or more of B, Al, Mg, Ti, Nb, W, Sc, Si, V, Fe, Y, Mo, Ce, Hf, Ta, La and Sr.
In paragraph 1, The above-mentioned positive active material is a positive active material for a lithium secondary battery having a residual lithium increase rate of 20% or less at a temperature of 25±3℃ and a relative humidity of 50±15%.
In paragraph 1, The positive electrode active material having the above coating layer formed thereon is a positive electrode active material for a lithium secondary battery having a residual lithium reduction rate of 55% or more relative to the doped nickel-containing metal oxide.
In paragraph 1, A positive electrode active material for a lithium secondary battery, wherein the average particle size (D50) of the positive electrode active material is 3 μm or more.
In paragraph 1, A positive electrode active material for a lithium secondary battery, wherein the crystal size of the nickel-containing metal oxide having the above-mentioned coating layer is 200 nm or larger.
A positive electrode for a lithium secondary battery comprising a positive electrode active material according to any one of claims 1 to 12.
A lithium secondary battery comprising a positive electrode for a lithium secondary battery according to claim 13.

Description

Cathode active material for lithium secondary battery and lithium secondary battery comprising the same The present embodiments relate to a positive electrode active material for a lithium secondary battery and a lithium secondary battery containing the same. Driven by the recent explosive demand for electric vehicles and the need for increased driving range, the development of high-capacity, high-energy-density secondary batteries to meet these demands is actively underway worldwide. In particular, high-nickel NCM cathode materials with high nickel content are being used to satisfy these requirements. However, as the nickel content increases, the particle strength decreases, leading to the occurrence of microcracks during charging and discharging. Additionally, this results in an increase in the specific surface area of the cathode material, which in turn increases the reaction with the electrolyte and leads to increased gas generation. Furthermore, due to structural instability, the phenomenon of cation mixing increases, in which unstable Ni³⁺ is reduced to stable Ni²⁺ and converted into stable NiO. Therefore, it is difficult to actually apply this as a cathode active material for lithium-ion batteries used in electric vehicles or energy storage. To solve this, a method was proposed to manufacture a cathode material in the form of a single particle with the size of the primary particle maximized, rather than in the form of a multi-particle secondary particle formed by the aggregation of primary particles, and then apply it. However, in general, to manufacture a cathode material in the form of a single particle, firing must be carried out at a higher temperature compared to multi-particle materials, and at this time, under-firing often occurs, resulting in layered structure crystal defects and causing electrochemical properties such as capacity and output to deteriorate. In addition, when the firing temperature was lowered to address this, there was a problem where the grain size within the individual grains did not grow sufficiently, leading to a deterioration in grain strength and lifespan characteristics. Terms such as first, second, and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and/or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and/or components. When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %. In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components. Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Cathode active material for lithium secondary batteries As mentioned above, the single-particle cathode active material may undergo under-sintering, resulting in defects in the layered crystal structure or a decrease in particle strength, which leads to problems such as reduced high-temperature lifespan and resistance characteristics. However, in this embodiment, this problem was solved by doping a metal oxide using at le