Positive electrode active material, preparation method therefor, and positive electrode comprising same

Abstract

Provided are a positive electrode active material, a method for preparing same, and a positive electrode comprising same. The positive electrode active material includes secondary particles in which a plurality of primary particles are aggregated, wherein the primary particle includes a core portion including a lithium transition metal oxide and a surface portion including a first element, and the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof. Both capacity characteristics and stability can be improved through the preparation of the positive electrode active material, and a battery including the positive electrode active material may exhibit improved rate characteristics and lifespan characteristics.

Description

Anode active material, method of manufacturing the same, and anode including the same

[0001] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0185477 filed December 13, 2024 and Korean Patent Application No. 10-2025-0191122 filed December 5, 2025, and includes all contents disclosed in the documents of said Korean patent applications as part of the specification.

[0002] The present invention relates to a positive electrode active material, a method for manufacturing the same, and a positive electrode including the same. Specifically, the invention relates to a positive electrode active material having a surface formed on a primary particle, a method for manufacturing the same, and a positive electrode including the same. More specifically, the invention relates to a positive electrode active material comprising a secondary particle formed by aggregating a plurality of primary particles, wherein the primary particle comprises a core comprising a lithium transition metal oxide and a surface portion comprising a first element, wherein the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof, a method for manufacturing the same, and a positive electrode including the same.

[0003] With the increasing technological development and demand for mobile devices, the demand for rechargeable batteries as an energy source is rapidly rising. Among these rechargeable batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used.

[0004] Lithium transition metal oxides are used as cathode active materials for lithium secondary batteries; among these, lithium cobalt composite metal oxides such as LiCoO2 have been primarily used due to their high operating voltage and excellent capacity characteristics. However, LiCoO2 has very poor thermal properties due to the descaling of its crystal structure following lithium delithiation, and because it is expensive, there are limitations to its mass use as a power source in fields such as electric vehicles.

[0005] As materials to replace lithium cobalt composite metal oxides, lithium manganese composite metal oxides (such as LiMnO2 or LiMn2O4), lithium iron phosphate compounds (such as LiFePO4), or lithium nickel composite metal oxides (such as LiNiO2) have been developed. Among these, research on cathodes utilizing high-nickel (High Ni) cathode active materials, which exhibit excellent capacity characteristics, has been actively conducted. However, high-nickel cathode active materials have problems such as poor thermal stability; if an internal short circuit occurs due to external pressure during charging, the cathode active material itself decomposes, leading to battery rupture and ignition.

[0006] Furthermore, secondary batteries using liquid electrolytes carry potential risks of leakage, ignition, and explosion. Consequently, using solid electrolytes as a replacement is gaining attention as an alternative to overcome these safety issues. However, when using solid electrolytes, particularly sulfide-based solid electrolytes, side reactions occur at the interface between the positive electrode active material and the solid electrolyte, leading to a degradation in lifespan characteristics.

[0007] Accordingly, attempts are being made to improve stability and electrochemical properties by forming a coating layer on the surface of the positive electrode active material; however, conventionally known coating methods alone have limitations in improving such stability and electrochemical properties.

[0008] Accordingly, there is a need to develop cathode active materials that can ensure stability by suppressing side reactions between the cathode active material and the electrolyte within the battery, while simultaneously improving electrochemical properties such as battery capacity and lifespan.

[0009] [Prior Art Literature]

[0010] [Patent Literature]

[0011] (Patent Document 1) Korean Patent Publication No. 10-2648141

[0012] The objective of the present invention is to provide a positive electrode active material capable of securing the initial capacity and efficiency of a battery while simultaneously improving rate characteristics and lifespan characteristics, wherein the positive electrode comprises a plurality of primary particles aggregated into secondary particles, the primary particles comprising a core comprising a lithium transition metal oxide and a surface portion comprising a first element, and the first element comprising a combination thereof selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof.

[0013] Another objective of the present invention is to provide a method for manufacturing the positive electrode active material.

[0014] Another objective of the present invention is to provide a positive electrode comprising the positive electrode active material.

[0015] A first aspect of the present invention provides a positive electrode active material comprising a plurality of primary particles aggregated into secondary particles, wherein the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element, and the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof.

[0016] In one embodiment of the present invention, the fact that the primary particle includes a surface portion comprising a first element means that C 제1 원소,외측 / C 제1 원소,내측 This means that it is 2.5 or less.

[0017] In one embodiment of the present invention, the thickness of the surface portion is 0.1 nm to 10 nm.

[0018] In one embodiment of the present invention, the secondary particle comprises a coating layer containing a second element, wherein the second element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca and combinations thereof.

[0019] In one embodiment of the present invention, the content of the first element in the secondary particle is 0.1% to 1.5% by weight based on the total weight of the secondary particle.

[0020] In one embodiment of the present invention, the content of the second element in the secondary particle is 0.1% to 1.5% by weight based on the total weight of the secondary particle.

[0021] In one embodiment of the present invention, the first element is derived from a raw material having a particle size of 1 nm to 50 nm.

[0022] In one embodiment of the present invention, the secondary particle has a composition represented by the following formula 1.

[0023] [Equation 1]

[0024] Li a [Ni b Co c M d M1 e M2 f ]O2

[0025] In the above Equation 1, a, b, c, d, e, and f are each 0.8≤a≤1.5, 0.4≤b<1, 0≤c≤0.15, 0 ≤d≤0.4, 0≤e≤0.2, and 0≤f≤0.2, and M is selected from the group consisting of Mn, Al, or a combination thereof, and M1 and M2 are different from each other and are each independently selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Si, La, and Ca.

[0026] A second aspect of the present invention provides a method for manufacturing a positive electrode active material, wherein the positive electrode active material comprises secondary particles formed by aggregating a plurality of primary particles, and the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element, wherein the first element comprises being selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof, and the method comprises the step of mixing a positive electrode active material precursor, a lithium raw material, and a first element raw material.

[0027] In one embodiment of the present invention, the first elemental raw material has a particle size of 1 nm to 50 nm.

[0028] A third aspect of the present invention provides a positive electrode comprising a positive electrode active material and a solid electrolyte, wherein the positive electrode active material comprises secondary particles formed by the aggregation of a plurality of primary particles, and the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element, and the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof.

[0029] In one embodiment of the present invention, the solid electrolyte is a sulfide-based solid electrolyte.

[0030] In one embodiment of the present invention, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m Sn (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (where p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0≤x≤2), Li 7-x PS 6-x I x It includes being selected from a group consisting of (where 0≤x≤2) and combinations thereof.

[0031] A positive electrode active material according to one embodiment of the present invention comprises secondary particles formed by the aggregation of a plurality of primary particles, wherein the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element, thereby having excellent initial efficiency and stability characteristics of the positive electrode active material. When applied to a battery, these characteristics can improve the performance of the battery, such as increasing rate characteristics and lifespan characteristics.

[0032] [Fig. 1] is a schematic diagram of a particle according to one embodiment of the present invention.

[0033] [Fig. 2] is an SEM image of the positive electrode active material according to Example 4 of the present invention.

[0034] [Fig. 3] is an SEM-EDS analysis image of the positive electrode active material according to Example 1 of the present invention.

[0035] [Fig. 4] is an SEM-EDS analysis image of the positive electrode active material according to Comparative Example 3 of the present invention.

[0036] [Fig. 5] is an SEM-EDS analysis image of the positive electrode active material according to Example 4 of the present invention.

[0037] [Fig. 6] is a TEM-EDS analysis image of the positive electrode active material according to Example 4 of the present invention.

[0038] [Fig. 7] is a TEM-EDS analysis image of the positive electrode active material according to Example 1 of the present invention.

[0039] [Fig. 8] is an EELS analysis graph of the cathode active material according to Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0040] [Fig. 9] is an EELS analysis image of the cathode active material according to Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0041] The present invention will be described in more detail below.

[0042] Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the configurations described in the embodiments described in this specification are merely one preferred embodiment of the invention and do not represent all of the technical spirit of the invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0043] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0044] In this specification, "%" means weight percent unless otherwise explicitly indicated.

[0045] Where measurement conditions and methods are not specifically described for the physical properties described in this specification, said physical properties are measured according to measurement conditions and methods generally used by a person skilled in the art in the relevant technical field.

[0046]

[0047] The present invention will be described in detail below.

[0048]

[0049] positive electrode active material

[0050] The present invention provides a positive electrode active material.

[0051] In one embodiment of the present invention, the positive active material comprises secondary particles formed by the aggregation of a plurality of primary particles.

[0052] Hereinafter, each part of the positive active material according to one embodiment of the present invention will be described in detail.

[0053]

[0054] (1) Primary particles

[0055] In one embodiment of the present invention, the primary particle comprises a core containing a lithium transition metal oxide and a surface portion containing a first element. The surface portion is formed on the outer edge of the core. When the lithium transition metal oxide is included in the positive electrode active material, high capacity characteristics and lifespan characteristics can be expected.

[0056] In addition, since the primary particle includes a surface portion, when the positive electrode active material containing the primary particle is applied to a battery, the surface area where side reactions with the electrolyte, particularly the solid electrolyte in an all-solid-state battery, may occur is reduced, thereby minimizing the interfacial resistance with the electrolyte and preventing the occurrence of internal cracks within the particle, thereby suppressing the side reactions and simultaneously improving the stability of the positive electrode active material.

[0057] The first element mentioned above is included in the positive electrode active material and can improve the ion conductivity of the positive electrode active material, and is not particularly limited as long as it is commonly used in the relevant technical field. For example, it may be a transition metal such as yttrium (Y), zirconium (Zr), titanium (Ti), or vanadium (V), or an element that can behave like a transition metal such as boron (B).

[0058] In one embodiment of the present invention, the thickness of the surface portion is 0.1 nm to 10 nm. Specifically, the thickness is 0.1 nm or more, 0.5 nm or more, 1 nm or more, 1.5 nm or more, 2 nm or more, 2.5 nm or more, 3 nm or more, 3.5 nm or more, 4 nm or more, or 4.5 nm or more, 10 nm or less, 9.5 nm or less, 9 nm or less, 8.5 nm or less, 8 nm or less, 7.5 nm or less, 7 nm or less, 6.5 nm or less, 6 nm or less, 5.5 nm or less, or 5 nm or less, and may be 0.1 nm to 10 nm, 0.5 nm to 8 nm, or 2 nm to 8 nm. When the thickness of the surface portion satisfies the above range, a surface portion suitable for preventing side reactions with the electrolyte can be formed, and the production efficiency of the cathode active material can be improved.

[0059] In one embodiment of the present invention, the first element refers to an element capable of reacting with lithium to form a lithium composite oxide. In one embodiment of the present invention, the first element comprises being selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof. By including the first element selected from the group, the ionic conductivity of the cathode active material can be improved, and side reactions with the electrolyte can be suppressed more effectively.

[0060] In one embodiment of the present invention, the first element comprises being selected from the group consisting of Zr, Nb, Ti, Mo, La, Mg, Si, and combinations thereof.

[0061] In one embodiment of the present invention, the first element is titanium.

[0062] In one embodiment of the present invention, the first element is derived from a raw material having a particle size of 1 nm to 50 nm. Specifically, the particle size of the first element raw material is 1 nm or more, 5 nm or more, 10 nm or more, 15 nm or more, or 20 nm or more; 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, or 25 nm or less; and may be 1 nm to 50 nm, 5 nm to 40 nm, or 10 nm to 30 nm. When the particle size of the first element raw material satisfies the above range, the first element raw material can penetrate into the interior of the secondary particle and uniformly form a surface portion on the surface of the primary particle contained within the secondary particle.

[0063] The fact that the primary particle includes a surface portion containing a first element means that the first element is evenly distributed into the interior of the secondary particle containing the primary particle, and does not mean that the first element is distributed only on the exterior or outermost surface of the primary particle. Specifically, it means that the difference between the content of the first element in the interior region of the secondary particle and the content of the first element in the exterior region is small.

[0064] In one embodiment of the present invention, the fact that the primary particle includes a surface portion comprising a first element means that C 제1 원소,외측 / C 제1 원소,내측 This means that it is 2.5 or less. Specifically, the above C 제1 원소,외측 / C 제1 원소,내측0 or more, greater than 0, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more, 1.3 or more, or 1.4 or more, 2.5 or less, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2 or less, 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, or 1.5 or less, and may mean 0 to 2.5, greater than 0 and 2 or less, or 0.5 to 1.5.

[0065] The above C 제1 원소,내측 and C 제1 원소,외측 Each represents the atomic percentage of the first element within the inner region and the outer region of the secondary particle. The inner region and the outer region are the regions corresponding to the region near the center (Region A) and the region near the surface (Region B), respectively, when the region of the particle is divided based on a point corresponding to half the distance from the center of the secondary particle to the outermost surface, as shown in [Fig. 7]. Specifically, the center is the center of a circle that is tangent to the particle at the point where the major axis of the secondary particle intersects the circumference of the secondary particle, with the major axis serving as the diameter.

[0066] The above C 제1 원소,내측 and C 제1 원소,외측 It may be calculated based on the total atomic percentage of transition metals included in the secondary particles, and specifically, if the secondary particles include a lithium transition metal oxide containing nickel, it may be calculated based on the total atomic percentage of nickel and the first element.

[0067] C as described above 제1 원소,내측 and C 제1 원소,외측 It is possible to confirm the distribution of specific elements, particularly transition metal elements, within a certain material, and can be measured through methods commonly used in the relevant technical field. Specifically, the above C 제1 원소,내측 and C 제1 원소,외측It can be calculated by a method of capturing an image of a substance, analyzing the distribution of elements within the image, and then calculating the content of a specific particle region within the image and the content of two or more different elements distributed in said particle region. For example, the elemental distribution can be measured using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), but is not limited thereto. In addition, the distinction of specific regions within an image can be performed using image analysis software or programs such as Velox, Gwyddion software, Mountains SEM software, ImageJ, rule-based algorithms, deep learning models based on Convolutional Neural Networks (CNNs) such as U-Net and Fully Convolutional Network, or segmentation techniques using said models, or algorithms that can be used for shape analysis, such as Python, but any method capable of recognizing and distinguishing specific shapes within an image can be used without special restrictions and can be performed by hardware, software, or a combination thereof.

[0068] In one embodiment of the present invention, the C 제1 원소,내측 and C 제1 원소,외측 ...was measured via TEM-EDS. Specifically, images of the particle cross-section were captured using TEM, the distribution of nickel and the first element on the particle cross-section was analyzed using TEM-EDS, and the atomic percentage of the first element was calculated based on the total atomic percentage of nickel and the first element in the inner and outer regions using Velox software, thereby C 제1 원소,내측 and C제1 원소,외측 derived.

[0069] In one embodiment of the present invention, the C 제1 원소,내측 and C 제1 원소,외측 The standard deviation is 1.5 atomic% or less. Specifically, the standard deviation is 0 atomic% or more, greater than 0 atomic%, 0.1 atomic% or more, 0.2 atomic% or more, or 0.3 atomic% or more; 1.5 atomic% or less, 1.4 atomic% or less, 1.3 atomic% or less, 1.2 atomic% or less, 1.1 atomic% or less, 1 atomic% or less, 0.9 atomic% or less, 0.8 atomic% or less, 0.7 atomic% or less, 0.6 atomic% or less, 0.5 atomic% or less, or 0.4 atomic% or less; and may be 0 atomic% to 1.5 atomic%, greater than 0 atomic% to 1 atomic% or less, or 0.1 atomic% to 0.8 atomic%. When the standard deviation satisfies the above range, the first element may be evenly distributed inside the secondary particle and form a surface portion on the primary particle, thereby contributing to the improvement of battery performance.

[0070] In one embodiment of the present invention, the C 제1 원소,내측 and C 제1 원소,외측 The average is 0.1 atomic% to 2 atomic%. Specifically, the average is 0.1 atomic% or more, 0.2 atomic% or more, 0.3 atomic% or more, 0.4 atomic% or more, 0.5 atomic% or more, 0.6 atomic% or more, 0.7 atomic% or more, or 0.8 atomic% or more, 2 atomic% or less, 1.9 atomic% or less, 1.8 atomic% or less, 1.7 atomic% or less, 1.6 atomic% or less, 1.5 atomic% or less, 1.4 atomic% or less, 1.3 atomic% or less, 1.2 atomic% or less, 1.1 atomic% or less, 1 atomic% or less, or 0.9 atomic% or less, and may be 0.1 atomic% to 2 atomic%, 0.1 atomic% to 1.5 atomic%, or 0.1 atomic% to 1 atomic%.

[0071] In one embodiment of the present invention, the C 제1 원소,내측The amount is 0.1 atomic% to 2 atomic%. Specifically, the above C 제1 원소,내측 The amount may be 0.1 atomic% or more, 0.2 atomic% or more, 0.3 atomic% or more, 0.4 atomic% or more, 0.5 atomic% or more, or 0.6 atomic% or more, 2 atomic% or less, 1.9 atomic% or less, 1.8 atomic% or less, 1.7 atomic% or less, 1.6 atomic% or less, 1.5 atomic% or less, 1.4 atomic% or less, 1.3 atomic% or less, 1.2 atomic% or less, 1.1 atomic% or less, 1 atomic% or less, 0.9 atomic% or less, 0.8 atomic% or less, or 0.7 atomic% or less, and may be 0.1 atomic% to 2 atomic%, 0.1 atomic% to 1 atomic%, or 0.1 atomic% to 0.8 atomic%.

[0072] In one embodiment of the present invention, the C 제1 원소,외측 The amount is 0.1 atomic% to 2 atomic%. Specifically, the above C 제1 원소,외측 It may be 0.1 atomic% or more, 0.2 atomic% or more, 0.3 atomic% or more, 0.4 atomic% or more, 0.5 atomic% or more, 0.6 atomic% or more, 0.7 atomic% or more, 0.8 atomic% or more, or 0.9 atomic% or more, 2 atomic% or less, 1.9 atomic% or less, 1.8 atomic% or less, 1.7 atomic% or less, 1.6 atomic% or less, 1.5 atomic% or less, 1.4 atomic% or less, 1.3 atomic% or less, 1.2 atomic% or less, 1.1 atomic% or less, or 1 atomic% or less, and may be 0.1 atomic% to 2 atomic%, 0.1 atomic% to 1.5 atomic%, or 0.1 atomic% to 1 atomic%.

[0073] The above C 제1 원소,내측 and C 제1 원소,외측 When the above average and standard deviation satisfy the above atomic % range, an even surface area can be formed on the primary particles included in the secondary particles, and accordingly, side reactions between the positive active material and the electrolyte can be effectively suppressed.

[0074] In one embodiment of the present invention, the length of the major axis of the primary particle is 100 nm to 1500 nm. Specifically, the average particle size is 100 nm or more, 200 nm or more, 300 nm or more, 400 nm or more, or 500 nm or more, and 1500 nm or less, 1400 nm or less, 1300 nm or less, 1200 nm or less, 1100 nm or less, 1000 nm or less, 900 nm or less, 800 nm or less, 700 nm or less, or 600 nm or less, and may be 100 nm to 1500 nm, 200 nm to 1200 nm, or 200 nm to 800 nm.

[0075] In one embodiment of the present invention, the length of the short axis of the primary particle is 50 nm to 1000 nm. Specifically, the average particle size is 50 nm or more, 100 nm or more, 200 nm or more, or 300 nm or more, 1000 nm or less, 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, 500 nm or less, or 400 nm or less, and may be 50 nm to 1000 nm, 50 nm to 800 nm, or 100 nm to 500 nm.

[0076] The major axis of the primary particle above refers to the longest distance (d) between two parallel tangent planes of the 2D image (cross-section) of the primary particle as shown in [Fig. 1], and the minor axis refers to the shortest distance (d) between two parallel tangent planes of the 2D image (cross-section) of the particle.

[0077] In one embodiment of the present invention, the aspect ratio of the primary particle is 0.2 to 1.2. Specifically, the aspect ratio is 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, or 0.65 or more, 1.2 or less, 1.15 or less, 1.1 or less, 1.05 or less, 1 or less, 0.95 or less, 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, or 0.7 or less, and may be 0.2 to 1.2, 0.2 to 1, or 0.4 to 0.8.

[0078] The above aspect ratio is a value corresponding to the length of the major axis / the length of the minor axis of the primary particle.

[0079] When the lengths of the major and minor axes and the aspect ratio of the primary particles satisfy the above range, the secondary particles containing the primary particles may have a size suitable for battery utilization.

[0080] The particle size of the primary particle above refers to the distance between the two points furthest apart among the cross-sections of the primary particle, as shown in [Fig. 2(c)].

[0081] In one embodiment of the present invention, the primary particle is in the form of a rod (rod-type).

[0082] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel.

[0083] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel and further comprises a material selected from the group consisting of cobalt, manganese, aluminum, and combinations thereof.

[0084] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel and cobalt, and further comprises one selected from the group consisting of manganese, aluminum, and combinations thereof.

[0085] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel, cobalt, and manganese.

[0086] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel, and the nickel content is 60 mol% to 99 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the nickel content may be 60 mol% or more, 65 mol% or more, 70 mol% or more, 75 mol% or more, or 80 mol% or more, 99 mol% or less, 95 mol% or less, 90 mol% or less, or 85 mol% or less, and may be 60 mol% to 99 mol%, 70 mol% to 95 mol%, or 80 mol% to 90 mol%. When the nickel content satisfies the above range, the performance of the battery can be improved when applied to a battery, and it may possess thermal stability suitable for battery application.

[0087] In one embodiment of the present invention, the lithium transition metal oxide comprises cobalt, and the content of the cobalt is 1 mol% to 20 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the content of the cobalt is 1 mol% or more, 2 mol% or more, 3 mol% or more, or 4 mol% or more, 20 mol% or less, 15 mol% or less, 10 mol% or less, 9 mol% or less, 8 mol% or less, 7 mol% or less, 6 mol% or less, or 5 mol% or less, and may be 1 mol% to 20 mol%, 1 mol% to 15 mol%, or 2 mol% to 10 mol%. When the content of the cobalt satisfies the above range, it may have capacity characteristics suitable for battery application and facilitate operation at high voltage.

[0088] In one embodiment of the present invention, the lithium transition metal oxide comprises manganese, and the content of the manganese is 1 mol% to 30 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the content of the manganese may be 1 mol% or more, 2 mol% or more, 3 mol% or more, 4 mol% or more, 5 mol% or more, or 10 mol% or more, 30 mol% or less, 25 mol% or less, 20 mol% or less, or 15 mol% or less, and may be 1 mol% to 30 mol%, 1 mol% to 25 mol%, or 5 mol% to 20 mol%. When the content of the manganese satisfies the above range, it may have capacity characteristics suitable for battery application.

[0089] In one embodiment of the present invention, the surface portion comprises lithium titanium oxide.

[0090] In one embodiment of the present invention, the surface portion comprises lithium titanium oxide represented by the following formula 2.

[0091] [Equation 2]

[0092] Li j Ti k O4

[0093] In the above chemical formula 2, j is 0.8 ≤ j ≤ 1.2. Specifically, j may be 0.8 ≤ j ≤ 1.2, 0.8 ≤ j ≤ 1.1, or 0.9 ≤ j ≤ 1.1.

[0094] In the above chemical formula 2, k is 1.6 ≤ k ≤ 2.2. Specifically, k may be 1.6 ≤ k ≤ 2.2, 1.6 ≤ k ≤ 2, or 1.6 ≤ k ≤ 1.8.

[0095] In one embodiment of the present invention, by including lithium titanium oxide represented by Formula 2 on the surface portion, it is possible to prevent the electrolyte, particularly the solid electrolyte interface film, from being excessively thick on the surface of the positive electrode active material including the surface portion, and to control thermal runaway factors, thereby improving the electrochemical characteristics and stability of the battery, and to facilitate the entry and exit of lithium ions, thereby improving the charge and discharge characteristics of the battery.

[0096] In one embodiment of the present invention, the lithium titanium oxide is Li4Ti5O 12 am.

[0097]

[0098] (2) Secondary particles

[0099] In one embodiment of the present invention, the secondary particle comprises a coating layer containing a second element. By including the coating layer, when the positive electrode active material comprising the secondary particle is applied to a battery, direct interfacial contact with the electrolyte, particularly the solid electrolyte in an all-solid-state battery, is suppressed, thereby reducing interfacial resistance and suppressing side reactions between the positive electrode active material and the electrolyte. Accordingly, the capacity and lifespan characteristics of the battery comprising the positive electrode active material can be improved.

[0100] The second element mentioned above may also be included in the positive electrode active material to improve the ion conductivity of the positive electrode active material, and is not particularly limited as long as it is commonly used in the relevant technical field. For example, it may be a transition metal such as yttrium (Y), zirconium (Zr), titanium (Ti), or vanadium (V), or an element that can behave like a transition metal such as boron (B).

[0101] In one embodiment of the present invention, the second element comprises being selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, and combinations thereof. By including the second element selected from the group, the ionic conductivity of the positive electrode active material can be improved, and side reactions with the electrolyte can be suppressed more effectively.

[0102] In one embodiment of the present invention, the second element is selected from the group consisting of Y, W, B, Ti, V and combinations thereof.

[0103] In one embodiment of the present invention, the second element is boron.

[0104] In one embodiment of the present invention, the thickness of the coating layer is 1 nm to 20 nm. Specifically, the thickness of the coating layer is 1 nm or more, 2 nm or more, 3 nm or more, 4 nm or more, 5 nm or more, 6 nm or more, 7 nm or more, 8 nm or more, or 9 nm or more; 20 nm or less, 19 nm or less, 18 nm or less, 17 nm or less, 16 nm or less, 15 nm or less, 14 nm or less, 13 nm or less, 12 nm or less, 11 nm or less, or 10 nm or less; and may be 1 nm to 20 nm, 1 nm to 15 nm, or 5 nm to 15 nm. When the thickness of the coating layer satisfies the above range, a surface suitable for preventing adverse reactions with the electrolyte can be formed, and the production efficiency of the cathode active material can be increased.

[0105] In one embodiment of the present invention, the content of the first element in the secondary particle is 0.01 wt% to 1.5 wt% based on the total weight of the secondary particle. Specifically, the content of the first element is 0.01 wt% or more, 0.05 wt% or more, or 0.1 wt% or more, and 1.5 wt% or less, 1.4 wt% or less, 1.3 wt% or less, 1.2 wt% or less, 1.1 wt% or less, 1 wt% or less, 0.9 wt% or less, 0.8 wt% or less, 0.7 wt% or less, 0.6 wt% or less, 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, or 0.2 wt% or less, and may be 0.01 wt% to 1.5 wt%, 0.05 wt% to 1 wt%, or 0.1 wt% to 0.5 wt%. When the content of the first element satisfies the above range, the surface portion containing the first element can be formed to a degree suitable for suppressing side reactions between the positive active material and the electrolyte.

[0106] In one embodiment of the present invention, the surface portion comprises lithium titanium oxide, and the content of lithium titanium oxide in the secondary particle is 0.01 weight% to 1.5 weight% based on the total weight of the secondary particle. Specifically, the content of the lithium titanium oxide may be 0.01 wt% or more, 0.05 wt% or more, 0.1 wt% or more, 0.15 wt% or more, 0.2 wt% or more, or 0.25 wt% or more, 1.5 wt% or less, 1.4 wt% or less, 1.3 wt% or less, 1.2 wt% or less, 1.1 wt% or less, 1 wt% or less, 0.9 wt% or less, 0.8 wt% or less, 0.7 wt% or less, 0.6 wt% or less, 0.5 wt% or less, 0.4 wt% or less, or 0.3 wt% or less, and may be 0.01 wt% to 1.5 wt%, 0.1 wt% to 1 wt%, or 0.2 wt% to 0.8 wt%. When the content of the lithium titanium oxide satisfies the above range, the surface portion containing the lithium titanium oxide can be formed to a degree suitable for suppressing side reactions between the positive electrode active material and the electrolyte.

[0107] In one embodiment of the present invention, the content of the second element in the secondary particle is 0.01 wt% to 1 wt% based on the total weight of the secondary particle. Specifically, the content of the second element is 0.01 wt% or more, 0.02 wt% or more, 0.03 wt% or more, 0.04 wt% or more, or 0.05 wt% or more, and 1 wt% or less, 0.9 wt% or less, 0.8 wt% or less, 0.7 wt% or less, 0.6 wt% or less, 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, 0.2 wt% or less, or 1 wt% or less, and may be 0.01 wt% to 1 wt%, 0.01 wt% to 0.5 wt%, or 0.05 wt% to 0.2 wt%. When the content of the second element satisfies the above range, a coating layer containing the second element can be formed to a degree suitable for suppressing side reactions between the positive active material and the electrolyte.

[0108] In one embodiment of the present invention, the average particle size of the secondary particles is 1 μm to 50 μm. Specifically, the average particle size is 1 μm or more, 2 μm or more, 3 μm or more, or 4 μm or more, and 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less, and may be 1 μm to 50 μm, 1 μm to 30 μm, or 2 μm to 20 μm. When the average particle size satisfies the above range, it may exhibit energy density and internal resistance suitable for battery utilization.

[0109] In one embodiment of the present invention, the secondary particle has a composition represented by the following formula 1.

[0110] [Equation 1]

[0111] Li a [Ni b Co c M d M1e M2 f ]O2

[0112] In the above Equation 1, a is 0.8≤a≤1.5, and specifically, a can be 0.8≤a≤1.5, 0.8≤a≤1.3, or 0.9≤a≤1.2.

[0113] In the above Equation 1, b is 0.4≤b<1, and specifically, b may be 0.4≤b<1, 0.6≤b≤0.99, or 0.7≤b≤0.9.

[0114] In the above Equation 1, c is 0≤c≤0.15, and specifically, c may be 0≤c≤0.15, 0.01≤c≤0.15, or 0.01≤c≤0.1.

[0115] In the above Equation 1, d is 0≤d≤0.4, and specifically, d may be 0≤d≤0.4, 0≤d≤0.2 or 0.05≤d≤0.2.

[0116] In the above Equation 1, e is 0 ≤ e ≤ 0.2, and specifically, e may be 0 ≤ e ≤ 0.2, 0.001 ≤ e ≤ 0.1, or 0.002 ≤ e ≤ 0.01.

[0117] In the above Equation 1, f is 0≤f≤0.2, and specifically, f may be 0≤f≤0.2, 0.001≤f≤0.1, or 0.004≤f≤0.02.

[0118] In the above Equation 1, M is selected from the group consisting of Mn, Al, or a combination thereof. Specifically, M may be Mn.

[0119] In the above Equation 1, M1 and M2 are different from each other and are each independently selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Si, La and Ca.

[0120] In one embodiment of the present invention, M1 and M2 are different from each other and are each independently selected from the group consisting of Ti and B.

[0121] In one embodiment of the present invention, M1 is Ti and M2 is B.

[0122]

[0123] Method for manufacturing positive electrode active material

[0124] The present invention provides a method for manufacturing a positive electrode active material.

[0125] In one embodiment of the present invention, the positive electrode active material comprises a plurality of primary particles aggregated into secondary particles, and the primary particles comprise a central part comprising a lithium transition metal oxide and a surface part comprising a first element.

[0126] In one embodiment of the present invention, the manufacturing method is a method for manufacturing the anode active material described above.

[0127] In one embodiment of the present invention, the manufacturing method comprises the step of mixing a positive electrode active material precursor, a lithium raw material, and the first element raw material.

[0128] The above mixing is not particularly limited as long as it is a method commonly used in the relevant technical field. The purpose of the above mixing is to uniformly disperse various raw materials, and it may be carried out using milling processes such as ball milling or jet milling, or mixing methods utilizing high-speed rotational force such as an intensive mixer.

[0129] In one embodiment of the present invention, the mixture of the positive electrode active material precursor, the lithium raw material, and the first element raw material is a dry mixture.

[0130] The above-mentioned positive electrode active material precursor refers to a material containing the said element as a raw material such as lithium or a transition metal constituting the positive electrode active material precursor, and may be, for example, a lithium transition metal oxide, but is not limited thereto as long as it is commonly used in the relevant technical field.

[0131] The above lithium raw material may be a lithium-containing sulfate, nitrate, acetate, carbonate, oxalate, citrate, halide, hydroxide, or oxyhydroxide, etc. For example, Li2CO3, LiNO3, LiNO2, LiOH, LiOH·H2O, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7, or a mixture thereof may be used, and one of these alone or a mixture of two or more may be used. Specifically, it may be Li2CO3 or LiOH, but is not limited thereto as long as it is commonly used in the relevant technical field for the manufacture of cathode active materials.

[0132] In one embodiment of the present invention, the lithium raw material is LiOH.

[0133] In one embodiment of the present invention, the positive active material precursor includes a nickel raw material.

[0134] In one embodiment of the present invention, the positive electrode active material precursor comprises a nickel raw material and further comprises a transition metal raw material selected from the group consisting of cobalt, manganese, aluminum, and combinations thereof.

[0135] In one embodiment of the present invention, the positive electrode active material precursor comprises nickel and cobalt raw materials and further comprises a transition metal raw material selected from the group consisting of manganese, aluminum, and combinations thereof.

[0136] In one embodiment of the present invention, the positive active material precursor comprises nickel, cobalt, and manganese raw materials.

[0137] In one embodiment of the present invention, the positive active material precursor is represented by the following formula 3.

[0138] [Equation 3]

[0139] LiNi x Co y M z O2

[0140] In the above Equation 1, M is selected from the group consisting of Mn, Al, and combinations thereof. Specifically, M may be Mn.

[0141] The above x is 0 <x<1이다. 구체적으로, 상기 x는 0<x<1, 0.4≤x≤0.99 또는 0.6≤x≤0.9일 수 있다.

[0142] The above y is 0 <y<1이다. 구체적으로, 상기 y는 0<y<1, 0.01≤y≤0.3 또는 0.01≤y≤0.1일 수 있다.

[0143] The above z is 0 <z<1이다. 구체적으로, 상기 z는 0<z<1, 0.01≤z≤0.4 또는 0.05≤z≤0.2일 수 있다.

[0144] For the above x, y, and z, x+y+z=1.

[0145] The mixing ratio of the above-mentioned positive electrode active material precursor and the lithium raw material can be determined to a range that satisfies the mole fraction of the first element and lithium within the surface portion of the finally manufactured positive electrode active material. Specifically, the lithium raw material may be mixed in an amount of 0.01 wt% to 0.5 wt% based on the total weight of the positive electrode active material precursor, and more specifically, may be mixed in an amount of 0.01 wt% to 0.5 wt%, 0.05 wt% to 0.4 wt%, or 0.1 wt% to 0.3 wt%.

[0146] The first element mentioned above is included in the positive electrode active material and can improve the ion conductivity of the positive electrode active material. It is not particularly limited as long as it is commonly used in the relevant technical field. The raw material of the first element may be an acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide of the first element, and specifically may be a hydroxide or an oxide, but is not limited thereto as long as it is commonly used for manufacturing the positive electrode active material in the relevant technical field.

[0147] In one embodiment of the present invention, the first elemental raw material is TiO2.

[0148] In one embodiment of the present invention, the first elemental raw material has a particle size of 1 nm to 50 nm. Specifically, the particle size of the first elemental raw material is 1 nm or more, 5 nm or more, 10 nm or more, 15 nm or more, or 20 nm or more, 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, or 25 nm or less, and may be 1 nm to 50 nm, 5 nm to 40 nm, or 10 nm to 30 nm. When the particle size of the first elemental raw material satisfies the above range, the first elemental raw material can penetrate into the interior of the secondary particle and uniformly form a surface portion on the surface of the primary particle contained within the secondary particle.

[0149] In one embodiment of the present invention, the mixing of the positive active material precursor, the lithium raw material, and the first element raw material comprises (S1) a step of mixing the positive active material precursor and the first element raw material, and (S2) a step of mixing the mixture of the positive active material precursor and the first element raw material with the lithium raw material. When the mixing of the positive active material precursor, the lithium raw material, and the first element raw material is performed in two steps as described above, the positive active material precursor, the lithium raw material, and the first element raw material can be mixed more uniformly.

[0150] The mixing in step (S1) above is not particularly limited as long as it is a method commonly used in the relevant technical field. The mixing is intended to uniformly disperse various raw materials and can be performed using a milling process such as ball milling or jet milling, or a mixing method utilizing high-speed rotational force such as an intensive mixer.

[0151] In one embodiment of the present invention, the mixing in step (S1) is dry mixing.

[0152] The mixing in step (S2) above is not particularly limited as long as it is a method commonly used in the relevant technical field. The mixing is intended to uniformly disperse various raw materials and can be performed using a milling process such as ball milling or jet milling, or a mixing method utilizing high-speed rotational force such as an intensive mixer.

[0153] In one embodiment of the present invention, the mixing in step (S2) is dry mixing.

[0154] In one embodiment of the present invention, the manufacturing method further comprises, after the step of (1) mixing the positive active material precursor of the lithium transition metal oxide, the lithium raw material, and the first element raw material, (2) the step of manufacturing a sintered product by sintering the mixture prepared in step (1).

[0155] In one embodiment of the present invention, the firing in step (2) is performed at 200°C to 1200°C. Specifically, the firing is performed at 200°C or higher, 250°C or higher, 300°C or higher, 350°C or higher, 400°C or higher, 450°C or higher, 500°C or higher, 550°C or higher, 600°C or higher, 650°C or higher, or 700°C or higher, and is performed at 1200°C or lower, 1150°C or lower, 1100°C or lower, 1050°C or lower, 1000°C or lower, 950°C or lower, 900°C or lower, 850°C or lower, 800°C or lower, or 750°C or lower, and can be performed at 200°C to 1200°C, 500°C to 1200°C, or 700°C to 1000°C.

[0156] In one embodiment of the present invention, the firing in step (2) is performed for 2 to 8 hours. Specifically, the firing may be performed for 2 hours or more, 3 hours or more, 4 hours or more, or 5 hours or more, 8 hours or less, 7 hours or less, or 6 hours or less, and may be performed for 2 to 8 hours, 3 to 7 hours, or 4 to 6 hours.

[0157] When the calcination temperature and calcination time in step (2) above satisfy the above range, the surface portion of the primary particle is evenly formed on the outer edge of the center of the primary particle, thereby reducing the contact area between the positive active material and the electrolyte, allowing for smooth movement of lithium ions, and the surface portion can exhibit strength suitable for battery application.

[0158] In one embodiment of the present invention, the manufacturing method further includes, after step (2), a step (3) of mixing the sintered product with a second element raw material.

[0159] The above-mentioned second element may also be included in the positive active material to improve the ion conductivity of the positive active material, and is not particularly limited as long as it is commonly used in the relevant technical field. The above-mentioned second element raw material may be an acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide of the above-mentioned second element, and specifically may be a hydroxide or an oxide, but is not limited thereto as long as it is commonly used for manufacturing the positive active material in the relevant technical field.

[0160] In one embodiment of the present invention, the second elemental raw material is H3BO3.

[0161] The mixing in step (3) above is not particularly limited as long as it is a method commonly used in the relevant technical field. The mixing is intended to uniformly disperse various raw materials and can be performed using a milling process such as ball milling or jet milling, or a mixing method using high-speed rotational force such as an intensive mixer.

[0162] In one embodiment of the present invention, the mixing in step (3) is dry mixing.

[0163] In one embodiment of the present invention, the manufacturing method further includes the step of crushing the product of step (2) before mixing in step (3).

[0164] In one embodiment of the present invention, the manufacturing method comprises, after step (3), (4) heat-treating the mixture prepared in step (3) at 100°C to 500°C for 2 to 8 hours.

[0165] In one embodiment of the present invention, the heat treatment in step (4) is performed at 100°C to 500°C. Specifically, the heat treatment is performed at 100°C or higher, 150°C or higher, 200°C or higher, 250°C or higher, or 300°C or higher, and is performed at 500°C or lower, 450°C or lower, 400°C or lower, or 350°C or lower, and can be performed at 100°C to 500°C, 200°C to 400°C, or 250°C to 350°C.

[0166] In one embodiment of the present invention, the heat treatment in step (4) is performed for 2 to 8 hours. Specifically, the heat treatment may be performed for 2 hours or more, 3 hours or more, 4 hours or more, or 5 hours or more, 8 hours or less, 7 hours or less, or 6 hours or less, and may be performed for 2 to 8 hours, 3 to 7 hours, or 4 to 6 hours.

[0167] When the heat treatment temperature and heat treatment time in step (4) above satisfy the above range, a suitable coating layer can be formed while maintaining the structural stability of the positive electrode active material, and accordingly, the productivity of the positive electrode active material can be improved.

[0168]

[0169] anode

[0170] The present invention also provides an anode.

[0171] In one embodiment of the present invention, the positive electrode comprises a positive electrode active material and a solid electrolyte, wherein the positive electrode active material comprises secondary particles formed by the aggregation of a plurality of primary particles, and the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element.

[0172] The above-mentioned solid electrolyte is intended to facilitate the movement of lithium ions and may be any solid electrolyte commonly used. Specifically, it may be an inorganic solid electrolyte such as a polymer-based solid electrolyte, a sulfide-based solid electrolyte, or an oxide-based solid electrolyte, but is not limited thereto as long as it is commonly used in the relevant technical field.

[0173] The above-mentioned polymer-based solid electrolyte comprises a polymer resin and a lithium salt, and may be a solid polymer electrolyte in the form of a mixture of a solvated lithium salt and a polymer resin, or a polymer gel electrolyte in which an organic electrolyte containing an organic solvent and a lithium salt is incorporated into a polymer resin, but is not limited thereto as long as it is commonly used in the relevant technical field.

[0174] The above-mentioned sulfide-based solid electrolyte contains sulfur atoms among the electrolyte components and is not limited to particularly specific components; it may include one or more of crystalline solid electrolytes, amorphous solid electrolytes (glassy solid electrolytes), and glass ceramic solid electrolytes. Specific examples of the above-mentioned sulfide-based solid electrolyte include LPS-type sulfides containing sulfur and phosphorus, Li4-xGe1-xPxS4 (x=0.1~2, specifically x=3 / 4, 2 / 3), Li 10±1 MP2X 12 (M=Ge, Si, Sn, Al, X=S, Se), Li 3.833 Sn 0.833 As 0.166 S4, Li4SnS4, Li 3.25 Ge 0.25 P 0.75 S4, Li2S-P2S5, B2S3-Li2S, xLi2S-(100-x)P2S5(x=70~80), Li2S-SiS2-Li3N, Li2S-P2S5-LiI, Li2S-SiS2-LiI, Li2S-B2S3-LiI, Li 3.25 Ge 0.25 P 0.75Examples include S4, but are not limited to those commonly used in the relevant technical field.

[0175] The above oxide-based solid electrolyte is an LLTO-based compound (La,Li)TiO3, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A=Ca, Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP-based compounds (Li 1+x Al x Ge 2-x (PO4)3, where 0≤x≤1, 0≤y≤1), LATP-based compounds such as Li2O-Al2O3-TiO2-P2O5 (Li 1+x Al x Ti 2-x (PO4)3, where 0≤x≤1, 0≤y≤1), Li 1+x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x (PO4)3(wherein, 0≤x≤1, 0≤y≤1), Li3N, LISICON, Lipon-based compounds (Li 3+y PO 4-x N x Examples include , where 0≤x≤1, 0≤y≤1), perovskite compounds ((La, Li)TiO3), nasicon compounds such as LiTi2(PO4)3, and LLZO compounds containing lithium, lanthanum, zirconium and oxygen as components, and combinations thereof may be included, but are not limited thereto as long as they are commonly used in the relevant technical field.

[0176] In one embodiment of the present invention, the positive active material is the positive active material described above.

[0177] In one embodiment of the present invention, the solid electrolyte is a sulfide-based solid electrolyte.

[0178] In one embodiment of the present invention, the anode includes the sulfide-based solid electrolyte, thereby allowing for more effective reduction of the interfacial resistance of the anode active material and suppression of side reactions with the electrolyte.

[0179] In one embodiment of the present invention, the sulfide-based solid electrolyte is represented by the following Formula 4.

[0180] [Equation 4]

[0181] Li l M' m S n X' o

[0182] In the above Equation 4, M' is selected from the group consisting of Sn, Mg, Ba, B, Al, Ga, In, Si, Ge, Pb, N, P, As, Sb, Bi, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W and La.

[0183] In one embodiment of the present invention, M' is selected from the group consisting of B, Si, Ge, P, and N.

[0184] In the above Equation 4, X' is selected from the group consisting of F, Cl, Br, I, Se, Te, and O.

[0185] In one embodiment of the present invention, X' is selected from the group consisting of F, Cl, Br, I, and O.

[0186] In Equation 4 above, l is 0 <l≤6이다. 구체적으로, 상기 l은 0<l≤6, 2≤l≤6 또는 4≤l≤6일 수 있다.

[0187] In Equation 4 above, m is 0 <m≤6이다. 구체적으로, 상기 m은 0<m≤6, 0<m≤4 또는 0<m≤2일 수 있다.

[0188] In Equation 4 above, n is 0 <n≤6이다. 구체적으로, 상기 n은 0<n≤6, 2≤n≤6 또는 4≤n≤6일 수 있다.

[0189] In the above Equation 4, o is 0≤o≤6. Specifically, o can be 0≤o≤6, 0≤o≤5, or 0≤o≤3.

[0190] In one embodiment of the present invention, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (where p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0≤x≤2), Li 7-x PS 6-x I x It includes being selected from a group consisting of (where 0≤x≤2) and combinations thereof.

[0191] In one embodiment of the present invention, the sulfide-based solid electrolyte comprises a component selected from the group consisting of Li6PS5Cl, Li6PS5Br, Li6PS5I, and combinations thereof.

[0192] In one embodiment of the present invention, the sulfide-based solid electrolyte comprises Li6PS5Cl.

[0193] In one embodiment of the present invention, the sulfide-based solid electrolyte is in the form of argyrodite.

[0194] In one embodiment of the present invention, the anode comprises an anode current collector and an anode active material layer formed on at least one side of the anode current collector, wherein the anode active material layer comprises the anode active material and a solid electrolyte.

[0195] In one embodiment of the present invention, the content of the positive active material in the positive active material layer is 40% to 99% by weight based on the total weight of the positive active material layer. Specifically, the content of the positive active material is 40% or more by weight, 45% or more by weight, 50% or more by weight, 55% or more by weight, or 60% or more by weight, and 99% or less by weight, 95% or less by weight, 90% or less by weight, 85% or less by weight, 80% or less by weight, 75% or less by weight, 70% or less by weight, or 65% or less by weight, and may be 40% to 99% by weight, 50% to 95% by weight, or 50% to 80% by weight. When the content of the positive active material satisfies the above range, it can exhibit an energy density suitable for application to a battery.

[0196] In one embodiment of the present invention, the content of the solid electrolyte in the positive electrode active material layer is 20% to 50% by weight based on the total weight of the positive electrode active material layer. Specifically, it may be 20% or more, 25% or more, or 30% or more, 50% or less, 45% or less, 40% or less, or 35% or less, and may be 20% to 50%, 25% to 50%, or 30% to 40% by weight. When the content of the solid electrolyte satisfies the above range, the movement of lithium ions between the positive electrode and the negative electrode can be facilitated.

[0197] In one embodiment of the present invention, the positive active material layer further comprises a material selected from the group consisting of a conductive material, a binder, and combinations thereof.

[0198] The above conductive material is used to impart conductivity to the electrode, and is not specifically limited as long as it possesses electronic conductivity without causing chemical changes in the battery being constructed. Specifically, examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fibers; metal powder or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives. One of these alone or a mixture of two or more may be used, but is not limited thereto as long as it is commonly used in the relevant technical field.

[0199] In one embodiment of the present invention, the content of the conductive material in the positive active material layer is 0.1 wt% to 15 wt% based on the total weight of the positive active material layer. Specifically, the content of the conductive material is 0.1 wt% or more, 0.5 wt% or more, 1 wt% or more, 2 wt% or more, 3 wt% or more, or 4 wt% or more, and 15 wt% or less, 14 wt% or less, 13 wt% or less, 12 wt% or less, 11 wt% or less, 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, or 5 wt% or less, and may be 0.1 wt% to 15 wt%, 0.5 wt% to 10 wt%, or 1 wt% to 8 wt%. When the content of the conductive material satisfies the above range, it may exhibit electrical conductivity suitable for application to a battery.

[0200] The above binder is used to improve adhesion between positive active material particles and adhesion between the positive active material and the current collector, and is not particularly limited as long as it can bind the components of the positive without causing chemical changes in the battery. Specifically, any one selected from the group consisting of N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), or a mixture of two or more of these; N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP); conjugated diene rubber latex such as acrylonitrile-styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methylbutadiene methacrylate rubber (MBR), and butadiene rubber (BR); carboxymethylcellulose (CMC); starch, Examples include hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-dienter polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers. One or more of these may be used alone or as a mixture of two or more, but are not limited thereto as long as they are commonly used in the relevant technical field. The binder may be included in an amount of 0.1% to 15% by weight relative to the total weight of the positive electrode active material layer.

[0201] In one embodiment of the present invention, the positive current collector may include a highly conductive metal, and is not particularly limited as long as it allows the positive active material layer to adhere easily and is non-reactive within the voltage range of the battery. The positive current collector may be, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. Additionally, the positive current collector may typically have a thickness of 3 μm to 500 μm, and may form fine irregularities on the surface of the current collector to increase the adhesion of the positive active material. It may be used in various forms, such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0202] The above-mentioned anode may be manufactured according to a conventional anode manufacturing method, except for using the above-mentioned anode active material. For example, the above-mentioned anode may be manufactured by dissolving or dispersing the components constituting the anode active material layer, namely the anode active material, a solid electrolyte, a conductive material, and / or a binder, in a solvent to produce an anode composite, applying the anode composite to at least one surface of an anode current collector, and then drying and rolling; or by casting the anode composite onto a separate support and then laminating the film obtained by peeling it off from the support onto an anode current collector.

[0203] In one embodiment of the present invention, the solvent may be a solvent generally used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, or water, and one of these alone or a mixture of two or more may be used. The amount of solvent used is sufficient to dissolve or disperse the cathode active material, conductive material, binder, and dispersant, taking into account the coating thickness of the slurry and the manufacturing yield, and to have a viscosity that can exhibit excellent thickness uniformity when coated for cathode manufacturing thereafter.

[0204] In one embodiment of the present invention, the anode further comprises, in addition to the anode active material, sulfide-based solid electrolyte, conductive material, and binder described above, additives such as, for example, a filler, a coating agent, a dispersant, and an ion conductivity aid. Known materials generally used in electrodes of all-solid-state secondary batteries may be used as the filler, coating agent, dispersant, ion conductivity aid, etc.

[0205] In one embodiment of the present invention, the thickness of the anode is 70 μm to 150 μm.

[0206]

[0207] All-solid-state battery

[0208] The present invention also provides an all-solid-state battery.

[0209] In one embodiment of the present invention, the all-solid-state battery comprises a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive active material and a solid electrolyte, wherein the positive active material comprises secondary particles formed by the aggregation of a plurality of primary particles, and the primary particles comprise a core comprising a lithium transition metal oxide and a surface portion comprising a first element.

[0210] In one embodiment of the present invention, the anode is the anode described above.

[0211] In one embodiment of the present invention, the all-solid-state battery may optionally further include a battery container that accommodates the electrode assembly of the positive electrode, negative electrode, and solid electrolyte layer described above, and a sealing member that seals the battery container.

[0212] In one embodiment of the present invention, the cathode comprises a cathode current collector and a cathode active material layer located on the cathode current collector.

[0213] The above-mentioned negative current collector is not particularly limited as long as it possesses high conductivity without causing chemical changes in the battery. The above-mentioned negative current collector may be, for example, copper, stainless steel, aluminum, nickel, titanium, cobalt, iron, or calcined carbon, and may be a copper or stainless steel surface treated with carbon, nickel, titanium, cobalt, iron, silver, etc., or an aluminum-cadmium alloy. In addition, the above-mentioned negative current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive current collector, fine irregularities may be formed on the surface of the current collector to increase the adhesion of the negative active material. The above-mentioned negative current collector may be used in various forms, such as films, sheets, foils, nets, porous bodies, foams, nonwoven fabrics, etc., but is not limited thereto as long as it is commonly used in the relevant technical field.

[0214] In one embodiment of the present invention, the negative electrode active material layer further comprises a binder, a conductive material, and combinations thereof, together with the negative electrode active material.

[0215] In one embodiment of the present invention, the negative electrode active material is a compound capable of reversible intercalation and deintercalation of lithium. Specifically, it may include, for example, one or more selected from carbon-based negative electrode active materials or metal and metalloid negative electrode active materials, but is not limited thereto as long as they are commonly used in the art.

[0216] The above-mentioned carbon-based cathode active material may specifically be amorphous carbon. Amorphous carbon may be, for example, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, etc., but is not necessarily limited to these; any carbon classified as amorphous carbon in the relevant technical field is acceptable. Amorphous carbon is carbon that does not possess crystallinity or has very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon.

[0217] The above metal or metalloid cathode active material comprises one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), but is not necessarily limited to these; any metal cathode active material or metalloid cathode active material that forms an alloy or compound with lithium in the relevant technical field is acceptable. For example, nickel (Ni) is not a metal cathode active material because it does not form an alloy with lithium.

[0218] In one embodiment of the present invention, the negative active material layer comprises a type of negative active material among such negative active materials, or comprises a mixture of a plurality of different negative active materials. For example, the negative active material layer comprises only amorphous carbon, or comprises one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). Alternatively, the negative active material layer comprises a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of a mixture of amorphous carbon and silver (Ag), etc., is selected in weight ratios, for example, from 10:1 to 1:2, from 5:1 to 1:1, or from 4:1 to 2:1, but is not necessarily limited to these ranges and is selected according to the required characteristics of the all-solid-state battery. By having the negative electrode active material with such a composition, the cycle characteristics of the all-solid-state battery are further improved. The negative electrode active material may be included in the negative electrode active material layer in an amount of 80% to 99% by weight based on the total weight of the negative electrode active material layer.

[0219] The binder of the above-mentioned negative electrode active material layer is a component that assists in the bonding between the conductive material, the active material, and the current collector, and can typically be added to the negative electrode active material layer in an amount of 0.1% to 10% by weight based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), polyacrylonitrile, polyvinyl alcohol, polymethyl methacrylate, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof, but are not limited thereto as long as they are commonly used in the relevant technical field.

[0220] The conductive material of the above-mentioned negative electrode active material layer is a component for further improving the conductivity of the negative electrode active material, and may be added to the negative electrode active material layer in an amount of 10% by weight or less, preferably 5% by weight or less, based on the total weight of the negative electrode active material layer. Such conductive material is not particularly limited as long as it possesses conductivity without causing chemical changes in the battery. The above-mentioned conductive material may be, for example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers or metal fibers; fluorinated carbon; metal powders such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, but is not limited thereto as long as they are commonly used in the relevant technical field.

[0221] In one embodiment of the present invention, the thickness of the negative electrode active material layer is 50% or less of the thickness of the positive electrode active material layer. Specifically, it may be 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less.

[0222] In one embodiment of the present invention, the thickness of the negative electrode active material layer is 1 μm to 20 μm. Specifically, it may be 1 μm to 20 μm, 2 μm to 10 μm, or 3 μm to 7 μm.

[0223] When the thickness of the above-mentioned negative electrode active material layer satisfies the above range, the formation of lithium dendrites between the negative electrode active material layer and the negative electrode current collector can be prevented, and an internal resistance suitable for battery utilization can be exhibited.

[0224] In one embodiment of the present invention, the negative electrode active material layer further comprises additives such as a filler, a dispersant, and an ion conductivity aid.

[0225] The above cathode may be manufactured by applying and drying a composition for forming a cathode active material layer, prepared by dissolving or dispersing a cathode active material and optionally a binder and a conductive material in a solvent, onto a cathode current collector, or by casting the composition for forming a cathode active material layer onto a separate support and then laminating the film obtained by peeling from the support onto a cathode current collector.

[0226] The above-mentioned solid electrolyte layer may be a solid electrolyte commonly used for ion-conducting materials, specifically an inorganic solid electrolyte such as a polymer-based solid electrolyte, a sulfide-based solid electrolyte, or an oxide-based solid electrolyte, but is not limited thereto as long as it is commonly used in the relevant technical field.

[0227] The above solid electrolyte layer may include a solid electrolyte of the same type as the one included in the anode, or a different one.

[0228] For the above-mentioned polymer-based solid electrolyte and inorganic-based solid electrolyte, refer to the contents regarding the anode described above.

[0229] In one embodiment of the present invention, the elastic modulus, i.e., Young's modulus, of the solid electrolyte included in the solid electrolyte layer is 10 GPa to 35 GPa. Specifically, it is 10 GPa or more, 15 GPa or more, or 20 GPa or more, 35 GPa or less, 30 GPa or less, 27 GPa or less, 25 GPa or less, or 23 GPa or less, and 10 to 35 GPa, 15 GPa to 35 GPa, 15 GPa to 30 GPa, or 15 GPa to 25 GPa. When the elastic modulus satisfies the above range, pressurization and / or sintering of the solid electrolyte can be performed more easily.

[0230] In one embodiment of the present invention, the solid electrolyte layer comprises a sulfide-based solid electrolyte.

[0231] In one embodiment of the present invention, the solid electrolyte layer further comprises a binder. The binder may be, for example, styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto as long as it is commonly used in the art. The binder of the solid electrolyte layer may be of the same type as the positive electrode active material layer and the negative electrode active material layer, or may be different.

[0232] The above-mentioned all-solid-state battery can be manufactured by a manufacturing method commonly known in the relevant technical field, for example, by manufacturing a positive electrode, a negative electrode, and a solid electrolyte layer, respectively, and then stacking these layers.

[0233] Since an all-solid-state battery comprising a positive electrode active material according to one embodiment of the present invention stably exhibits excellent capacity characteristics, output characteristics, and lifespan characteristics, it is useful in fields such as portable devices like mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs) and electric vehicles (EVs).

[0234] There are no specific restrictions on the external shape of the above-mentioned solid-state battery, but it may be a cylindrical type using a can, a prismatic type, a pouch type, or a coin type.

[0235] An all-solid-state battery according to one embodiment of the present invention can be used not only as a battery cell used as a power source for a small device, but can also preferably be used as a unit cell in a medium-to-large battery module comprising a plurality of battery cells.

[0236]

[0237] The present invention also provides a battery module comprising the all-solid-state battery as a unit cell, a battery pack comprising the battery module, and a device comprising the battery pack as a power source.

[0238] Specific examples of the above-mentioned device include, but are not limited to, power tools that are powered by an electric motor; electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs); electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; and power storage systems.

[0239] Specific embodiments of the present invention are presented below. However, the embodiments described below are merely for the purpose of specifically illustrating or explaining the present invention and do not limit the present invention. Furthermore, details not described herein can be sufficiently technically inferred by a person skilled in the art, so their description is omitted.

[0240]

[0241] Examples

[0242]

[0243] <Example 1>

[0244] LiNi 0.83 Co 0.05 Mn 0.12 Nano TiO2 (manufactured by Sigma-Aldrich), having a particle size of 25 nm or less, was added as a first elemental raw material at a concentration of 0.86 wt% relative to the cathode active material precursor having a composition indicated by O2, and mixed at 3,000 rpm for 10 minutes using an intensive mixer (manufactured by EIRICH, EL1). A mixture was prepared by additionally adding 0.36 wt% of LiOH (manufactured by Sigma-Aldrich) relative to the precursor and mixing at 3,000 rpm for 10 minutes.

[0245] Subsequently, the above mixture is calcined at 700°C under an oxygen atmosphere for 5 hours to form Li4Ti5O on the primary particle surface. 12 A positive electrode active material having a surface portion containing 1% by weight based on the total weight of the positive electrode active material was prepared.

[0246]

[0247] <Example 2>

[0248] Li4Ti5O by adding the above first elemental raw material at 0.43 wt% and LiOH at 0.18 wt%. 12 A positive electrode active material having a surface portion containing 0.5% by weight based on the total weight of the positive electrode active material was prepared using the same method as in Example 1, except for the fact that the positive electrode active material was prepared using the same method as in Example 1.

[0249]

[0250] <Example 3>

[0251] Li4Ti5O is prepared by adding the above first elemental raw material at 0.22 wt% and LiOH at 0.09 wt%. 12 A positive electrode active material having a surface portion containing 0.25 wt% based on the total weight of the positive electrode active material was prepared using the same method as in Example 1, except for the fact that the positive electrode active material was prepared using the same method as in Example 1.

[0252]

[0253] <Example 4>

[0254] The positive electrode active material prepared in Example 2 above was used as the primary calcined product, and the primary calcined product was fed into a jet milling device (manufactured by Isaac E&C, 04-626c-WC Micron Master) and ground for 30 minutes at 3,000 rpm at a pressure of 1.5 bar. Subsequently, 0.58 wt% of H3BO3 (manufactured by Sigma-Aldrich) was added as the secondary element raw material to the ground primary calcined product, and the mixture was mixed for 10 minutes at 3,000 rpm using an intensive mixer (manufactured by EIRICH, EL1).

[0255] The above mixture is calcined at 310°C for 5 hours under an atmospheric conditions to form Li4Ti5O on the primary particle surface. 12 A positive electrode active material was prepared having a surface layer containing 0.5 wt% based on the total weight of the positive electrode active material and a coating layer of secondary particles containing 0.1 wt% of boron (B) based on the total weight of the positive electrode active material.

[0256]

[0257] <Example 5>

[0258] The above second element raw material was added at 0.29 wt%, and the cathode active material prepared in Example 3 was used as the primary calcined product, except that it was prepared in the same manner as Example 4.

[0259]

[0260] <Comparative Example 1>

[0261] The above positive active material was prepared in the same manner as in Example 1, except that it was calcined at 500°C.

[0262]

[0263] <Comparative Example 2>

[0264] The above positive active material was prepared in the same manner as in Example 1, except that it was calcined at 600°C.

[0265]

[0266] <Comparative Example 3>

[0267] It was prepared in the same manner as Example 2, except that TiO2 with a particle size of 200 nm to 300 nm was used as the first elemental raw material.

[0268]

[0269] <Comparative Example 4>

[0270] The above positive active material was prepared in the same manner as in Example 2, except that it was calcined at 400°C.

[0271]

[0272] <Comparative Example 5>

[0273] The above positive active material was prepared in the same manner as in Example 3, except that it was calcined at 400°C.

[0274]

[0275] <Comparative Example 6>

[0276] Except for firing at 400°C to manufacture the above primary fired product, it was manufactured in the same manner as in Example 4.

[0277]

[0278] <Comparative Example 7>

[0279] Except for firing at 400°C to manufacture the above primary fired product, it was manufactured in the same manner as in Example 5.

[0280]

[0281] <Comparative Example 8>

[0282] It was manufactured in the same manner as Example 5, except that the first element raw material and the second element raw material were not added.

[0283]

[0284] <Comparative Example 9>

[0285] It was manufactured in the same manner as Example 5, except that the above-mentioned first element raw material was not added.

[0286]

[0287] <Comparative Example 10>

[0288] It was manufactured in the same manner as Example 1, except that the first elemental raw material was not added and the second elemental raw material was added at a weight of 0.29%.

[0289]

[0290] Experimental Example

[0291]

[0292] <Experimental Example 1: Evaluation of Elemental Distribution Characteristics>

[0293] (1) SEM-EDS analysis

[0294] The surface of the cathode active material prepared in Example 2, Example 4, and Comparative Example 3 was Pt coated for 1 minute using an E-3500 (Hitach). Subsequently, the surface morphology of the surface-coated sample was analyzed using an SEM (JEOL, JSM-7610F-plus). Among the obtained images, the image of Example 4 is shown in [Fig. 2].

[0295] Subsequently, SEM-EDS analysis was performed to evaluate the coating morphology of Ni, Co, Mn, and Ti in the cathode active materials prepared in Example 2 and Comparative Example 3, and the coating morphology of Ti and B in the cathode active material prepared in Example 4. SEM analysis was performed as described above, and subsequently, EDS analysis was performed to map the distribution of each element within the cathode active material under conditions of acceleration voltage 2.5 KV (B), 10 KV (elements other than B), and WD 15 mm. Images obtained through the mapping are shown in [Figs. 3] to [Figs. 5].

[0296] (2) TEM-EDS analysis

[0297] TEM-EDS analysis was performed to evaluate the Ti coating morphology of the cathode active materials prepared in the above Examples 1, 4, Comparative Example 1, and Comparative Example 2. The cross-section of the cathode active material of Example 4 was analyzed using TEM (Thermo Fisher Scientific, Titan), and subsequently, the distribution of Ni and Ti elements in the cathode active material was mapped using EDS-Mapping (ChemiSTEM technology).

[0298] The cathode active materials of Example 1, Comparative Example 1, and Comparative Example 2 were analyzed for particle cross-sections, and cross-sectional samples for analysis were prepared using a Helios G4 (manufactured by Thermo Fisher Scientific). Subsequently, imaging was performed using a TEM (manufactured by Thermo Fisher Scientific, Spectra Ultra) at an acceleration voltage of 200 kV, and the distribution of Ni and Ti elements in the cathode active material was mapped using EDS-Mapping (ChemiSTEM technology).

[0299] For Example 4, mapping was performed after obtaining a specific image of the primary particle, and for Example 1, Comparative Example 1, and Comparative Example 2, CTi,내측 and C Ti,외측 To calculate the image of the particle cross-section, mapping was performed after obtaining the image. The image obtained through the mapping is shown in [Fig. 6] and [Fig. 7] (Fig. 6: Example 4, Fig. 7: Example 1).

[0300] For the image of Example 1 above, as shown in [Fig. 7], the inner and outer regions were distinguished based on the point halfway between the center and the outermost surface, and the atomic percentage of Ti was calculated relative to the total atomic percentages of Ni and Ti in each inner and outer region, respectively, and C Ti,내측 and C Ti,외측 The above at% was calculated. The calculation was performed using Velox software (manufactured by Thermo), which is software for quantifying TEM-EDS analysis results.

[0301] For each cathode active material, a total of 2 particles were selected and C Ti,내측 and C Ti,외측 was calculated, and for each particle, C Ti,외측 / C Ti,내측 , C Ti,내측 and C Ti,외측 After calculating the mean and standard deviation of the values, the above C for the 2 particles Ti,외측 / C Ti,내측 , C Ti,내측 and C Ti,외측 The mean and standard deviation of the values ​​were calculated.

[0302] C calculated as the average value of each cathode active material calculated in this way Ti,외측 / C Ti,내측 , C Ti,내측 and C Ti,외측 The mean and standard deviation of the values ​​are shown in [Table 1] below.

[0303] (3) EELS analysis

[0304] Electron Energy Loss Spectroscopy (EELS) analysis was performed to evaluate the structural characteristics of the surface portion of the cathode active material prepared in Example 1, Comparative Example 1, and Comparative Example 2. Specifically, EELS images were obtained at an acceleration voltage of 200 kV using a TFS Spectra 300 STEM, and the constituent elements were analyzed through the obtained images. The EELS analysis graphs measured in the above manner are shown in [Fig. 8] and [Fig. 9].

[0305]

[0306] C Ti,외측 / C Ti,내측 Average (Atomic%) Standard Deviation (Atomic%) Example 11.42 1.61 0.40 Comparative Example 16.44 1.90 1.96 Comparative Example 23.05 2.06 1.47

[0307]

[0308] As shown in [Fig. 3], in the case of Example 2, which uses a titanium (Ti) raw material with a particle size of 25 nm or less, it can be seen that the Ti is evenly distributed into the interior of the secondary particle and mixed with the primary particle. In contrast, in the case of Comparative Example 3, which uses a Ti raw material with a particle size of 200 nm to 300 nm, it can be seen that the raw material is not evenly distributed into the interior due to the size of the raw material being larger than the internal pores of the secondary particle, and instead aggregates on the surface. Furthermore, in the case of Comparative Example 3, it can be seen that the raw material aggregates with each other on the exterior of the secondary particle. Through this, it can be seen that a raw material with a particle size of 25 nm or less must be used so that the element can be evenly distributed into the interior of the secondary particle and form a surface portion on the primary particle.

[0309] Furthermore, as shown in [Table 1] above, it can be seen that even when using raw materials with the same particle size of 25 nm or less, the degree of distribution into the interior of the particles varies depending on the calcination temperature. In the case of Example 1, in which calcination was performed at 700°C after mixing the raw materials, Ti was distributed even into the interior of the particles, and C Ti,외측 / C Ti,내측 It can be confirmed that this is 2 or less and has a standard deviation of 1.5 or less. In contrast, in the case of Comparative Examples 1 and 2, which were calcined at 500°C and 600°C, it can be seen that the raw material was not evenly distributed into the interior, resulting in larger ratios and standard deviations compared to the example. Through this, it can be seen that raw material with a size of 1 nm to 50 nm or less must be used and calcined at 700°C or higher to form an even surface area of ​​the element on the surface of the primary particle.

[0310] Furthermore, as shown in Figs. 8 and 9, in the case of Example 1, which was calcined at 700°C after mixing the raw materials, a peak is observed near 62 eV, unlike Comparative Examples 1 and 2, which were calcined at 500°C and 600°C, respectively, confirming that a high bonding force was formed between lithium and titanium. Additionally, in the region of 456 eV to 468 eV, only in the graph of Example 1, t 2g wa e g Through the observation of peak bifurcation, it can be seen that the amount of lithium titanium oxide produced is greater compared to the input raw material compared to Comparative Examples 1 and 2. This structural difference can also be confirmed in the OK edge spectrum, and [Fig. 9] also confirms that the most uniform lithium titanium oxide layer was formed in Example 1.

[0311] As shown in FIGS. 2, FIGS. 5, and FIGS. 6, in the case of Example 4 using titanium (Ti) raw material with a particle size of 25 nm or less, Li4Ti5O on the surface of the primary particles 12 It can be confirmed that a surface layer with a thickness of about 5 nm is evenly formed, and that the boron (B) coating layer is evenly formed on the surface of the secondary particles aggregated from the primary particles.

[0312]

[0313] <Experimental Example 2: Evaluation of Dose and Life Cycle Characteristics>

[0314] (1) Manufacturing of batteries

[0315] Using the positive electrode active material prepared in the above examples and comparative examples, a positive electrode mixture slurry was prepared by mixing the positive electrode active material at 60 wt%, Li6PS5Cl as a solid electrolyte at 35 wt%, and carbon nanofiber as a conductive material at 5 wt%.

[0316] Subsequently, a solid electrolyte pellet was prepared by pressurizing 150 mg of solid electrolyte Li6PS5Cl at a pressure of 175 MPa for 1 minute using a jig cell, and the anode mixture slurry was poured onto the pellet layer and pressurized at a pressure of 480 MPa for 5 minutes to prepare an anode.

[0317] A lithium metal foil with a thickness of 100 μm was laminated as the above-mentioned cathode and the cathode was manufactured by applying pressure of 50 MPa for 1 second, and then an all-solid-state battery in the form of a jig cell having a driving pressure of 35 MPa was manufactured using the above-mentioned anode and cathode.

[0318] (2) Evaluation of capacity and lifespan characteristics

[0319] For the all-solid-state battery according to the above manufacturing example, it was fixed in a jig inside a chamber at 60°C, and initial charging and discharging were performed under conditions of 0.1 C-rate to measure the initial discharge capacity and charge / discharge efficiency. At this time, the charging was performed using the CCCV method, and the discharging was performed using the CC method.

[0320] Afterwards, charging and discharging were performed twice. Each charge was performed under conditions of 0.1 C-rate, and each discharge was performed at 0.1 C-rate and 1 C-rate, respectively, to calculate the ratio of the discharge capacity at 1 C-rate to the discharge capacity at 0.1 C-rate.

[0321] In addition, for the all-solid-state battery manufactured as described above, charging in CC / CV mode at 0.5 C-rate to 4.25 V and then discharging in CC mode at 1 C-rate until it reaches 3.0 V was performed as one cycle, and this was repeated for 30 cycles. The life characteristics were evaluated by determining the percentage of the discharge capacity of the 30th cycle relative to the discharge capacity of the first cycle as the capacity retention rate.

[0322] The capacity and lifespan characteristics evaluated by the above method are shown in [Table 2] below.

[0323]

[0324] Initial Discharge Capacity (mAh / g) Charge / Discharge Efficiency (%) 1C / 0.1C (%) Capacity Retention Rate (%) Example 1 21487.580.1 - Example 2 21487.088.684.8 Example 3 21486.688.184.5 Example 4 21388.988.389.0 Example 5 21487.793.089.9 Comparative Example 4 21386.887.080.0 Comparative Example 5 21083.186.579.2 Comparative Example 6 21288.587.976.3 Comparative Example 7 21488.392.081.0 Comparative Example 8 21085.686.978.9 920986.085.775.5 Comparative Example 1020986.090.979.6

[0325]

[0326] As shown in [Table 2] above, when a battery is manufactured using the positive electrode active material of Examples 1 to 5, which comprises a plurality of primary particles aggregated into secondary particles, wherein the primary particles comprise a core containing a lithium transition metal oxide and a surface portion containing a first element, and the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof, it was confirmed that the battery has excellent capacity and efficiency characteristics.

[0327] When comparing a battery using the positive active material of Comparative Example 8 that does not include the surface portion with a battery using the positive active material of Examples 1 to 3 that includes the surface portion, it can be confirmed that when a surface portion is formed on the primary particle, the battery performance can be improved, and in particular, this effect is more superior in capacity characteristics, efficiency, and lifespan characteristics.

[0328] Furthermore, when comparing the cathode active materials of Examples 1 to 3, which were formed with lithium titanium oxide at 1 wt%, 0.5 wt%, and 0.25 wt%, respectively, it can be confirmed that the cathode active material of Example 2 showed the most excellent improvement effect not only in capacity and efficiency but also in rate and lifespan characteristics. Through this, it can be seen that performance improvement can be more effectively achieved by adjusting the content of the first element and the content of lithium titanium oxide to the range of Example 2.

[0329] In addition, when comparing the battery using the positive active material of Examples 1 to 3, in which only the surface portion of the primary particle is formed, with the battery using the positive active material of Examples 4 and 5, in which the surface portion and the coating layer of the secondary particle are formed, it can be confirmed that although the battery performance is improved by the formation of the surface portion alone, the improvement of battery performance, particularly the improvement of lifespan characteristics, can be achieved more effectively when the surface portion and the coating layer are formed simultaneously.

[0330] When comparing the battery using the positive active material of Example 5 and Example 5, in which the surface portion and the coating layer are formed simultaneously, with the battery using the positive active material of Comparative Example 9 and Comparative Example 10, in which only the coating layer is formed, it can be seen that the effect of improving battery performance as described above can be achieved only when the surface portion is formed on the primary particle.

[0331] Furthermore, when comparing the battery using the positive active material of Comparative Examples 4 to 7, which was calcined at 400°C, with the battery using the positive active material of Examples 2 to 5, which was calcined at 700°C, it can be seen that battery performance can be significantly improved when a surface layer is formed through calcination at 700°C. Through the difference in the degree of performance improvement depending on the calcination temperature, it can be seen that this difference in the degree of performance improvement was influenced by the distribution of Ti inside the active material particles as described above, and it can be seen that performance improvement is possible by performing calcination at 700°C or higher to form a surface layer containing the first element in the primary particles. Through [Fig. 8] and [Fig. 9], it can be seen that the even distribution of the first element inside the particles through calcination at 700°C or higher enables not only the formation of the surface layer of the primary particles but also strong bonding with lithium and the formation of uniform lithium oxide, and it can be seen that the formation of such stable lithium oxide contributed to the improvement of battery performance.

[0332] Accordingly, when a positive electrode active material is used in a battery, the battery performance, such as capacity, efficiency, and lifespan, can be improved by using a primary particle that comprises a secondary particle formed by aggregating multiple primary particles, wherein the primary particle comprises a core containing a lithium transition metal oxide and a surface portion containing a first element, and the first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof. Furthermore, it can be seen that the surface portion containing the first element on the primary particle can be formed by using a first element raw material with particles of 1 nm to 50 nm and performing calcination at 700°C or higher after mixing the first element raw material so that the first element is evenly distributed within the secondary particle, thereby improving the battery performance. Furthermore, it can be seen that the improvement of this effect is more effective when the content of the first element and the lithium oxide formed by the reaction with the first element is controlled, or when a coating layer is formed not only on the surface but also on the secondary particles.

[0333]

[0334] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. Includes secondary particles formed by the aggregation of multiple primary particles, and The above primary particle comprises a core containing a lithium transition metal oxide and a surface portion containing a first element, and The first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof. Positive active material.

2. In Claim 1, The fact that the above primary particle includes a surface portion containing a first element means that C 제1 원소,외측 / C 제1 원소,내측 This means that it is 2.5 or less, Positive active material.

3. In Claim 1, The thickness of the above surface portion is 0.1 nm to 10 nm, Positive active material.

4. In Claim 1, The above secondary particle includes a coating layer containing a second element, and The second element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, and combinations thereof, Positive active material.

5. In Claim 1, The content of the first element in the secondary particle is 0.01 weight% to 1.5 weight% based on the total weight of the secondary particle, Positive active material.

6. In Claim 4, The content of the second element in the secondary particle is 0.01 weight% to 1 weight% based on the total weight of the secondary particle, Positive active material.

7. In Claim 1, The first element is derived from a raw material having a particle size of 1 nm to 50 nm, Positive active material.

8. In Claim 1, The above secondary particle has a composition represented by the following formula 1, Positive active material. [Equation 1] The a [Nor b Co c M d M1 e M2 f ]O2 In the above Equation 1, a, b, c, d, e, and f are 0.8≤a≤1.5, 0.4≤b<1, 0≤c≤0.15, 0 ≤d≤0.4, 0≤e≤0.2, and 0≤f≤0.2, respectively, and M is selected from the group consisting of Mn, Al, or a combination thereof, and M1 and M2 are distinct from each other and are each independently selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Si, La, and Ca.

9. A method for manufacturing a positive electrode active material, The above positive active material includes secondary particles formed by the aggregation of a plurality of primary particles, and The above primary particle comprises a core containing a lithium transition metal oxide and a surface portion containing a first element, and The first element above includes being selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La and combinations thereof, and The above manufacturing method comprises the step of mixing a positive electrode active material precursor, a lithium raw material, and the first element raw material. Method for manufacturing positive electrode active material.

10. In Claim 9, The above-mentioned first elemental raw material is one having a particle size of 1 nm to 50 nm, Method for manufacturing positive electrode active material.

11. A cathode comprising a positive active material and a solid electrolyte, The above positive active material includes secondary particles formed by the aggregation of a plurality of primary particles, and The above primary particle comprises a core containing a lithium transition metal oxide and a surface portion containing a first element, and The first element is selected from the group consisting of Y, Zr, B, Ti, W, Nb, Sr, Mo, Mg, P, V, Ta, Ga, Ca, Si, La, and combinations thereof. anode.

12. In Claim 11, The above solid electrolyte is a sulfide-based solid electrolyte, anode.

13. In Claim 12, The above sulfide-based solid electrolytes are Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (where p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0≤x≤2), Li 7-x PS 6-x I x (wherein 0≤x≤2) and combinations thereof, including those selected from the group anode.

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