Lithium-rich nickel-rich cathode active material

Abstract

The present invention relates to a Li-rich cathode active material including a layered structure and an irregular rock salt structure, which exhibits high capacity and excellent cycle stability.

Description

Technical Field

[0001] The present invention relates to a positive electrode active material including a layered structure and an irregular rock salt structure, a method for manufacturing the positive electrode active material, use of the positive electrode active material in a battery, a battery including the positive electrode active material, and use of the battery.

Background Art

[0002] As seen in the number of electric vehicle (EV) in operation, which set a new record of exceeding 10 million units at the end of 2020, the electric vehicle market has been growing rapidly. Due to the prosperity of the electric vehicle market, the demand for high energy density Li-ion batteries that function as a power source is increasing. Over the past few decades, in order to pursue high energy density of batteries, extensive efforts have been made to explore potential candidate materials for both cathodes and anodes. Among them, conventional cathode candidates such as LiCoO2, LiFePO4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 have mainly the problem that the capacity is typically as low as less than 200 mAhg -1 and thus the energy density is low. Therefore, there is a strong demand for practical high energy density electrodes.

[0003] Ni-rich oxides have recently attracted increasing attention due to their high capacity (more than 200 mAhg -1 exceeding) and high operating potential (about 3.8 V). These compositions obtained from LiNiO2 are typically LiNi ξ Co Ψ Mn 1-ξ-Ψ O2 (so-called NMC) or LiNi ξ Co Ψ Al 1-ξ-ΨIt is O2 (so-called NCA), where ξ is typically greater than 0.8. However, these Ni-rich electrodes have problems with mechanical, electrochemical, and thermal stability. By doping these Ni-rich oxides with a small amount of high-valence transition metal ions such as molybdenum, some of these problems can be alleviated (Park et al, Energy Environ. Sci., 2021, 14, 6616 or Susai et al, Materials 2021, 14, 2070), but with this approach, a cathode active material with excellent mechanical stability, structural stability, and cycle stability required for high-energy density electrodes has not yet been obtained.

[0004] An object of the present invention is to provide a Li-rich cathode active material that exhibits a high capacity and excellent cycle stability.

[0005] A further object of the present invention is to provide a method for manufacturing the cathode active material.

[0006] A further object of the present invention is to provide the use of the cathode active material in a battery.

[0007] A further object of the present invention is to provide a battery including the cathode material.

[0008] A further object of the present invention is to provide the use of the battery in an electric vehicle.

Summary of the Invention

[0009] In a first aspect, the first object of the present invention is achieved by providing a cathode active material including a layered structure and an irregular rock salt structure.

[0010] The inventors have surprisingly found that this Li-rich cathode active material doped with a high-valent transition metal ion such as Mo exhibits high capacity and excellent cycle stability, particularly when compared with a Li-poor (or non-Li-rich) cathode active material, as demonstrated in the attached examples. Furthermore, the Li-rich cathode active material of the present invention has excellent mechanical reversibility and durability.

[0011] Without being bound by any theory, the inventors believe that these higher capacities, better cycle stability, and mechanical reversibility are achieved by the Li-rich cathode active material of the present invention, which includes a lamellar LiNiO2 structure and an irregular rock salt structure of Li4MoO5 twinned together, as evidenced by XRD, TEM, and NMR tests. The advantages of such twinning are fully demonstrated by the improvement in electrochemical performance, as the Coulombic efficiency and capacity of the first cycle increase with the increase in Li and Mo content. Furthermore, the inventors believe that the Li4MoO5 structure can act as a structural support that enables better mechanical reversibility with respect to the LiNiO2 structure.

[0012] In a further aspect, the present invention provides a method for manufacturing the cathode active material.

[0013] In a further aspect, the present invention provides the use of the cathode active material.

[0014] In a further aspect, the present invention provides a battery comprising the cathode active material.

[0015] In a further aspect, the present invention provides the use of the battery in an electric vehicle.

Brief Description of the Drawings

[0016]

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Mode for Carrying Out the Invention

[0017] To enable the implementation of the present invention, preferred embodiments will be described in detail in the drawings and the following mode for carrying out the invention. Although the present invention is described with reference to these specific preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention includes numerous alternatives, modifications, and equivalents as will become apparent by considering the following mode for carrying out the invention and the accompanying drawings.

[0018] As used in this specification and the claims, the term "comprising" should not be construed as being limited to the means recited thereafter, nor does it exclude other elements or steps. It should be construed as specifying the presence of the recited features, integers, steps, or components as described, but not excluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to a composition consisting only of components A and B. It means, with respect to the present invention, that the only relevant components of the composition are A and B. Thus, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of".

[0019] The positive electrode active material is defined as a material that is electrochemically active in the positive electrode. It should be understood that an active material is a material that can capture and release Li ions when exposed to a voltage change over a predetermined period.

[0020] In the framework of the present invention, atomic % means atomic percentage. Atomic % or "atomic percent" as an expression of the concentration of a given element means what percentage of all the atoms in the compound are atoms of that element. The term atomic % is synonymous with mol% or "mole percent".

[0021] Positive electrode active material In a first aspect, the present invention provides a positive electrode active material comprising a layered structure and an irregular rock salt structure.

[0022] In a preferred embodiment, the positive electrode active material of the present invention has the formula (I), Li 1+x M’ 1-x O2(I) [wherein x is in the range of 0 < x < 0.6], and provides a positive electrode active material.

[0023] A preferred embodiment is a positive electrode active material of the present invention, wherein M' is selected from the group consisting of Ni, Co, Mn, Q, M'', and combinations thereof; Q is an element other than Li, O, Ni, Mo, Co, Mn, and M'', preferably an element other than Li, O, Ni, Co, Mn, and M''; and M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof. In a specific preferred embodiment, M' is selected from the group consisting of Ni, Co, Mn, M'', and combinations thereof.

[0024] A specific preferred embodiment is a positive electrode active material according to formula (I) [wherein Q is 0.0 ≦ e ≦ 2.0 mol% with respect to M', preferably 0.1 ≦ e ≦ 1.5 mol% with respect to M', more preferably 0.2 ≦ e ≦ 1.0 mol% with respect to M', and most preferably 0.4 ≦ e ≦ 0.8 mol% with respect to M']. A highly preferred embodiment is a positive electrode active material according to the present invention, wherein e = 0.0 mol%.

[0025] A preferred embodiment is that M' is Ni having a content a of 70.0 ≦ a ≦ 97.0 mol% with respect to M', M'' having a content b with respect to M', where b is in the range of 0 < b ≦ 20.0 mol%, Co having a content c of 0.0 ≦ c ≦ 10.0 mol% with respect to M', Mn having a content d of 0.0 ≦ d ≦ 10.0 mol% with respect to M', and Q having a content e of 0.0 ≦ e ≦ 2.0 mol% with respect to M', and a, b, c, d, and e are measured by ICP-OES, and a + b + c + d + e = 100.0 mol%, which is a positive electrode active material of the present invention.

[0026] The preferred embodiment is the positive electrode active material according to the present invention, where 0.01 ≦ x ≦ 0.4, preferably 0.02 ≦ x ≦ 0.2, and most preferably 0.03 ≦ x ≦ 0.15. In a specific embodiment, the positive electrode active material is according to the present invention, where 0.07 ≦ x ≦ 0.4, preferably 0.08 ≦ x ≦ 0.2, and most preferably 0.09 ≦ x ≦ 0.15. A specific preferred embodiment is the positive electrode active material according to the present invention, where x ranges from 0.01 ≦ x ≦ 0.12, preferably 0.02 ≦ x ≦ 0.11, and more preferably 0.03 ≦ x ≦ 0.10. A specific preferred embodiment is the positive electrode active material according to the present invention, where x ranges from 0.07 ≦ x ≦ 0.12, preferably 0.07 ≦ x ≦ 0.11, and more preferably 0.07 ≦ x ≦ 0.10.

[0027] The preferred embodiment is the positive electrode active material according to the present invention, where a ranges from 75.0 ≦ a ≦ 96.0 mol% with respect to M', more preferably 78.0 ≦ a ≦ 95.0 mol%, and most preferably 80.0 ≦ a ≦ 94.0 mol%. In a specific embodiment, the positive electrode active material is according to the present invention, where a ranges from 75.0 ≦ a ≦ 90.0 mol% with respect to M', more preferably 78.0 ≦ a ≦ 88.0 mol%, and most preferably 80.0 ≦ a ≦ 86.0 mol%.

[0028] The preferred embodiment is the positive electrode active material according to the present invention, where b ranges from 1.0 ≦ b ≦ 15.0 mol%, preferably 2.0 ≦ b ≦ 12.5 mol%, and most preferably 3.0 ≦ b ≦ 10.0 mol%. In a specific embodiment, the positive electrode active material is according to the present invention, where 5.0 ≦ b ≦ 15.0 mol%, preferably 5.5 ≦ b ≦ 12.5 mol%, and most preferably 6.0 ≦ b ≦ 10.0 mol%.

[0029] The preferred embodiment is the positive electrode active material according to the present invention, where M'' is Cr, W, Mo, or a combination thereof, preferably W, Mo, or a combination thereof, and most preferably Mo.

[0030] A preferred embodiment is a positive electrode active material according to the present invention, wherein 0.1 ≦ c ≦ 9.0 mol% with respect to M', preferably 1.0 ≦ c ≦ 8.0 mol% with respect to M', and most preferably 2.0 ≦ c ≦ 8.0 mol% with respect to M'. A highly preferred embodiment is a positive electrode active material according to the present invention, wherein c = 0.0 mol%.

[0031] A preferred embodiment is a positive electrode active material according to the present invention, wherein 0.1 ≦ d ≦ 9.0 mol% with respect to M', preferably 1.0 ≦ d ≦ 8.5 mol% with respect to M', and most preferably 2.0 ≦ d ≦ 8.0 mol% with respect to M'. A highly preferred embodiment is a positive electrode active material according to the present invention, wherein d = 0.0 mol%.

[0032] A preferred embodiment is a positive electrode active material according to the present invention, wherein Q is selected from the group consisting of Al, B, Ba, Ca, Fe, Mg, S, Si, Sr, Y, Zn, and combinations thereof, preferably Al, B, S, Si, Y, and combinations thereof.

[0033] A preferred embodiment is a positive electrode active material according to the present invention, wherein 0.1 ≦ e ≦ 1.5 mol% with respect to M', preferably 0.2 ≦ e ≦ 1.0 mol% with respect to M', and most preferably 0.4 ≦ e ≦ 0.8 mol% with respect to M'. A highly preferred embodiment is a positive electrode active material according to the present invention, wherein e = 0.0 mol%.

[0034] As will be understood by those skilled in the art, the amounts of a, b, c, d, and e, particularly the amounts of Li, Ni, Co, Mn, Mo, and W, are measured by ICP-OES. For example, without limitation to the present invention, a PerkinElmer NexION 2000 ICP mass spectrometer can be used for ICP-OES measurements.

[0035] A preferred embodiment is the positive electrode active material of the present invention having an Li / M' ratio z, where M' is an element other than Li and O, z > 1, preferably z ≥ 1.01, more preferably z ≥ 1.05, still more preferably z ≥ 1.1, and most preferably z ≥ 1.2. A preferred embodiment is the positive electrode active material of the present invention having an Li / M' ratio z, where z < 1.5, preferably z ≤ 1.49, more preferably z ≤ 1.45, still more preferably z ≤ 1.4, and most preferably z ≤ 1.3. A preferred embodiment is the positive electrode active material of the present invention having an Li / M' ratio z, where 1 < z < 1.5, preferably 1.01 ≤ z ≤ 1.49, more preferably 1.05 ≤ z ≤ 1.45, still more preferably 1.1 ≤ z ≤ 1.4, and most preferably 1.2 ≤ z ≤ 1.3. In a specific preferred embodiment, the Li / M' ratio z is 1.05 ≤ z ≤ 1.27, preferably 1.1 ≤ z ≤ 1.27, more preferably 1.2 ≤ z ≤ 1.27. In a specific preferred embodiment, the Li / M' ratio z is 1.05 ≤ z ≤ 1.22, preferably 1.1 ≤ z ≤ 1.22, more preferably 1.15 ≤ z ≤ 1.22.

[0036] As will be understood by those skilled in the art, the Li / M' ratio z is a molar ratio (mol / mol).

[0037] A more preferred embodiment is formula (II), Li 1+y Ni (3-5y) / 3 M'' 2y / 3 O2(II) [wherein 0 < y ≦ 0.6 with respect to the total amount of Li, Ni and M'', preferably 0.01 ≦ y ≦ 0.4 with respect to the total amount of Li, Ni and M'', more preferably 0.02 ≦ y ≦ 0.2 with respect to the total amount of Li, Ni and M-]. The cathode active material of the present invention is represented by. In a specific preferred embodiment, y is in the range of 0.01 ≦ y ≦ 0.12 with respect to the total amount of Li, Ni and M'', preferably 0.02 ≦ y ≦ 0.11 with respect to the total amount of Li, Ni and M'', more preferably 0.03 ≦ y ≦ 0.1 with respect to the total amount of Li, Ni and M''. The cathode active material according to the present invention. In a specific preferred embodiment, y is in the range of 0.07 ≦ y ≦ 0.12 with respect to the total amount of Li, Ni and M'', preferably 0.07 ≦ y ≦ 0.11 with respect to the total amount of Li, Ni and M'', more preferably 0.07 ≦ y ≦ 0.1 with respect to the total amount of Li, Ni and M''. The cathode active material according to the present invention.

[0038] A more preferred embodiment is formula (II) [wherein M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb and combinations thereof, preferably M'' is Cr, W, Mo or a combination thereof, more preferably M'' is W, Mo or a combination thereof, and most preferably M'' is Mo]. The cathode active material of the present invention is represented by.

[0039] A highly preferred embodiment is formula (II)a, Li 1+ya Ni (3-5ya) / 3 Ti 2ya / 3 O2(II)a [wherein 0 < ya ≦ 0.6 with respect to the total amount of Li, Ni and Ti, preferably 0.01 ≦ ya ≦ 0.4 with respect to the total amount of Li, Ni and Ti, more preferably 0.02 ≦ ya ≦ 0.2 with respect to the total amount of Li, Ni and Ti], which is the positive electrode active material of the present invention. A specific preferred embodiment is that ya is in the range of 0.01 ≦ ya ≦ 0.12 with respect to the total amount of Li, Ni and Ti, preferably 0.02 ≦ ya ≦ 0.11 with respect to the total amount of Li, Ni and Ti, more preferably 0.03 ≦ ya ≦ 0.1 with respect to the total amount of Li, Ni and Ti, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that ya is in the range of 0.07 ≦ ya ≦ 0.12 with respect to the total amount of Li, Ni and Ti, preferably 0.07 ≦ ya ≦ 0.11 with respect to the total amount of Li, Ni and Ti, more preferably 0.07 ≦ ya ≦ 0.1 with respect to the total amount of Li, Ni and Ti, which is the positive electrode active material according to the present invention.

[0040] A highly preferred embodiment is formula (II)b, Li 1+yb Ni (3-5yb) / 3 Zr 2yb / 3 O2(II)b [wherein 0 ≦ yb ≦ 0.6 with respect to the total amount of Li, Ni and Zr, preferably 0.01 ≦ yb ≦ 0.4 with respect to the total amount of Li, Ni and Zr, more preferably 0.02 ≦ yb ≦ 0.2 with respect to the total amount of Li, Ni and Zr], which is the positive electrode active material of the present invention. A specific preferred embodiment is that yb is in the range of 0.01 ≦ yb ≦ 0.12 with respect to the total amount of Li, Ni and Zr, preferably 0.02 ≦ yb ≦ 0.11 with respect to the total amount of Li, Ni and Zr, more preferably 0.03 ≦ yb ≦ 0.1 with respect to the total amount of Li, Ni and Zr, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yb is in the range of 0.07 ≦ yb ≦ 0.12 with respect to the total amount of Li, Ni and Zr, preferably 0.07 ≦ yb ≦ 0.11 with respect to the total amount of Li, Ni and Zr, more preferably 0.07 ≦ yb ≦ 0.1 with respect to the total amount of Li, Ni and Zr, which is the positive electrode active material according to the present invention.

[0041] A highly preferred embodiment is formula (II)c, Li 1+yc Ni (3-5yc) / 3 Hf 2yc / 3 O2(II)c [wherein 0 < yc ≦ 0.6 with respect to the total amount of Li, Ni and Hf, preferably 0.01 ≦ yc ≦ 0.4 with respect to the total amount of Li, Ni and Hf, more preferably 0.02 ≦ yc ≦ 0.2 with respect to the total amount of Li, Ni and Hf], which is the positive electrode active material of the present invention. A specific preferred embodiment is that yc is in the range of 0.01 ≦ yc ≦ 0.12 with respect to the total amount of Li, Ni and Hf, preferably 0.02 ≦ yc ≦ 0.11 with respect to the total amount of Li, Ni and Hf, more preferably 0.03 ≦ yc ≦ 0.1 with respect to the total amount of Li, Ni and Hf, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yc is in the range of 0.07 ≦ yc ≦ 0.12 with respect to the total amount of Li, Ni and Hf, preferably 0.07 ≦ yc ≦ 0.11 with respect to the total amount of Li, Ni and Hf, more preferably 0.07 ≦ yc ≦ 0.1 with respect to the total amount of Li, Ni and Hf, which is the positive electrode active material according to the present invention.

[0042] A highly preferred embodiment is formula (II)d, Li 1+yd Ni (3-5yd) / 3 V 2yd / 3 O2(II)d [wherein 0 < yd ≤ 0.6 with respect to the total amount of Li, Ni and V, preferably 0.01 ≤ yd ≤ 0.4 with respect to the total amount of Li, Ni and V, more preferably 0.02 ≤ yd ≤ 0.2 with respect to the total amount of Li, Ni and V], which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yd is in the range of 0.01 ≤ yd ≤ 0.12 with respect to the total amount of Li, Ni and V, preferably 0.02 ≤ yd ≤ 0.11 with respect to the total amount of Li, Ni and V, more preferably 0.03 ≤ yd ≤ 0.1 with respect to the total amount of Li, Ni and V, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yd is in the range of 0.07 ≤ yd ≤ 0.12 with respect to the total amount of Li, Ni and Hf, preferably 0.07 ≤ yd ≤ 0.11 with respect to the total amount of Li, Ni and Hf, more preferably 0.07 ≤ yd ≤ 0.1 with respect to the total amount of Li, Ni and Hf, which is the positive electrode active material according to the present invention.

[0043] A highly preferred embodiment is formula (II)e, Li 1+ye Ni (3-5ye) / 3 Nb 2ye / 3 O2(II)e [wherein 0 < ye ≤ 0.6 with respect to the total amount of Li, Ni and Nb, preferably 0.01 ≤ ye ≤ 0.4 with respect to the total amount of Li, Ni and Nb, more preferably 0.02 ≤ ye ≤ 0.2 with respect to the total amount of Li, Ni and Nb], which is the positive electrode active material of the present invention. A specific preferred embodiment is that ye is in the range of 0.01 ≤ ye ≤ 0.12 with respect to the total amount of Li, Ni and Nb, preferably 0.02 ≤ ye ≤ 0.11, more preferably 0.03 ≤ ye ≤ 0.1, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that ye is in the range of 0.07 ≤ ye ≤ 0.12 with respect to the total amount of Li, Ni and Hf, preferably 0.07 ≤ ye ≤ 0.11 with respect to the total amount of Li, Ni and Hf, more preferably 0.07 ≤ ye ≤ 0.1 with respect to the total amount of Li, Ni and Hf, which is the positive electrode active material according to the present invention.

[0044] A highly preferred embodiment is formula (II)f, Li 1+yf Ni(3-5yf) / 3 Ta 2yf / 3 O2(II)f [Wherein, 0 < yf ≦ 0.6 with respect to the total amount of Li, Ni and Ta, preferably 0.01 ≦ yf ≦ 0.4 with respect to the total amount of Li, Ni and Ta, more preferably 0.02 ≦ yf ≦ 0.2 with respect to the total amount of Li, Ni and Ta], which is the positive electrode active material of the present invention. In a specific preferred embodiment, yf is in the range of 0.01 ≦ yf ≦ 0.12 with respect to the total amount of Li, Ni and Ta, preferably 0.02 ≦ yf ≦ 0.11 with respect to the total amount of Li, Ni and Ta, more preferably 0.03 ≦ yf ≦ 0.1 with respect to the total amount of Li, Ni and Ta, which is the positive electrode active material according to the present invention. In a specific preferred embodiment, yf is in the range of 0.07 ≦ yf ≦ 0.12 with respect to the total amount of Li, Ni and Hf, preferably 0.07 ≦ yf ≦ 0.11 with respect to the total amount of Li, Ni and Hf, more preferably 0.07 ≦ yf ≦ 0.1 with respect to the total amount of Li, Ni and Hf, which is the positive electrode active material according to the present invention.

[0045] A very preferred embodiment is formula (II)g, Li 1+yg Ni (3-5yg) / 3 Cr 2yg / 3 O2(II)g [Wherein, 0 < yg ≦ 0.6 with respect to the total amount of Li, Ni and Cr, preferably 0.01 ≦ yg ≦ 0.4 with respect to the total amount of Li, Ni and Cr, more preferably 0.02 ≦ yg ≦ 0.2 with respect to the total amount of Li, Ni and Cr], which is the positive electrode active material of the present invention. In a specific preferred embodiment, yg is in the range of 0.01 ≦ yg ≦ 0.12 with respect to the total amount of Li, Ni and Cr, preferably 0.02 ≦ yg ≦ 0.11 with respect to the total amount of Li, Ni and Cr, more preferably 0.03 ≦ yg ≦ 0.1 with respect to the total amount of Li, Ni and Cr, which is the positive electrode active material according to the present invention. In a specific preferred embodiment, yg is in the range of 0.07 ≦ yg ≦ 0.12 with respect to the total amount of Li, Ni and Cr, preferably 0.07 ≦ yg ≦ 0.11 with respect to the total amount of Li, Ni and Cr, more preferably 0.07 ≦ yg ≦ 0.1 with respect to the total amount of Li, Ni and Cr, which is the positive electrode active material according to the present invention.

[0046] A highly preferred embodiment is formula (II)h, Li 1+yh Ni (3-5yh) / 3 MO 2yh / 3 O2 (II)h [wherein 0 < yh ≦ 0.6 with respect to the total amount of Li, Ni and Mo, preferably 0.01 ≦ yh ≦ 0.4 with respect to the total amount of Li, Ni and Mo, more preferably 0.02 ≦ yh ≦ 0.2 with respect to the total amount of Li, Ni and Mo], which is the positive electrode active material of the present invention. A specific preferred embodiment is that yh is in the range of 0.01 ≦ yh ≦ 0.12 with respect to the total amount of Li, Ni and Mo, preferably 0.02 ≦ yh ≦ 0.11 with respect to the total amount of Li, Ni and Mo, more preferably 0.03 ≦ yh ≦ 0.1 with respect to the total amount of Li, Ni and Mo, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yh is in the range of 0.07 ≦ yh ≦ 0.12 with respect to the total amount of Li, Ni and Mo, preferably 0.07 ≦ yh ≦ 0.11 with respect to the total amount of Li, Ni and Mo, more preferably 0.07 ≦ yh ≦ 0.1 with respect to the total amount of Li, Ni and Mo, which is the positive electrode active material according to the present invention.

[0047] A highly preferred embodiment is formula (II)i, Li 1+yi Ni (3-5yi) / 3 W 2yi / 3 O2 (II)i [wherein 0 < yi ≦ 0.6 with respect to the total amount of Li, Ni, and W, preferably 0.01 ≦ yi ≦ 0.4 with respect to the total amount of Li, Ni, and W, more preferably 0.02 ≦ yi ≦ 0.2 with respect to the total amount of Li, Ni, and W], which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yi is in the range of 0.01 ≦ yi ≦ 0.12 with respect to the total amount of Li, Ni, and W, preferably 0.02 ≦ yi ≦ 0.11 with respect to the total amount of Li, Ni, and W, more preferably 0.03 ≦ yi ≦ 0.1 with respect to the total amount of Li, Ni, and W, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yi is in the range of 0.07 ≦ yi ≦ 0.12 with respect to the total amount of Li, Ni, and W, preferably 0.07 ≦ yi ≦ 0.11 with respect to the total amount of Li, Ni, and W, more preferably 0.07 ≦ yi ≦ 0.1 with respect to the total amount of Li, Ni, and W, which is the positive electrode active material according to the present invention.

[0048] A highly preferred embodiment is formula (II)j, Li 1+y Ni (3-5y) / 3 Sb 2y / 3 O2(II)j [wherein 0 < yj ≦ 0.6 with respect to the total amount of Li, Ni, and Sb, preferably 0.01 ≦ yj ≦ 0.4 with respect to the total amount of Li, Ni, and Sb, more preferably 0.02 ≦ yj ≦ 0.2 with respect to the total amount of Li, Ni, and Sb], which is the positive electrode active material of the present invention. A specific preferred embodiment is that yj is in the range of 0.01 ≦ yj ≦ 0.12 with respect to the total amount of Li, Ni, and Sb, preferably 0.02 ≦ yj ≦ 0.11 with respect to the total amount of Li, Ni, and Sb, more preferably 0.03 ≦ yj ≦ 0.1 with respect to the total amount of Li, Ni, and Sb, which is the positive electrode active material according to the present invention. A specific preferred embodiment is that yj is in the range of 0.07 ≦ yj ≦ 0.12 with respect to the total amount of Li, Ni, and W, preferably 0.07 ≦ yj ≦ 0.11 with respect to the total amount of Li, Ni, and W, more preferably 0.07 ≦ yj ≦ 0.1 with respect to the total amount of Li, Ni, and W, which is the positive electrode active material according to the present invention.

[0049] A highly preferred embodiment is formula (II)k, Li 1+yk Ni (3-5yk) / 3 Te 2yk / 3 O2(II)k [wherein, 0 < yk ≦ 0.6 with respect to the total amount of Li, Ni and Te, preferably, 0.01 ≦ yk ≦ 0.4 with respect to the total amount of Li, Ni and Te, more preferably, 0.02 ≦ yk ≦ 0.2 with respect to the total amount of Li, Ni and Te], which is the positive electrode active material of the present invention. In a specific preferred embodiment, yk is in the range of 0.01 ≦ yk ≦ 0.12, preferably, 0.02 ≦ yk ≦ 0.11, more preferably, 0.03 ≦ yk ≦ 0.1 with respect to the total amount of Li, Ni and Te, which is the positive electrode active material according to the present invention. In a specific preferred embodiment, yk is in the range of 0.07 ≦ yk ≦ 0.12, preferably, 0.07 ≦ yk ≦ 0.11, more preferably, 0.07 ≦ yk ≦ 0.1 with respect to the total amount of Li, Ni and Te, which is the positive electrode active material according to the present invention.

[0050] In a specific preferred embodiment, the positive electrode active material of the present invention includes a two-phase structure determined by a transmission electron microscope (TEM), preferably a scanning transmission electron microscope (STEM), more preferably a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM). For example, but not limited to the present invention, the two-phase structure can be measured by a probe-corrected Titan Themis Z electron microscope operating at 200 kV and equipped with a Super-X EDX detector. In a specific preferred embodiment, the two-phase structure includes a layered structure and an irregular rock salt structure, which is the positive electrode active material of the present invention. In a more preferred embodiment, the two-phase structure consists of a layered structure and an irregular rock salt structure.

[0051] In a specific preferred embodiment, the positive electrode active material of the present invention includes a layered structure and an irregular rock salt structure. In a more preferred embodiment, the positive electrode active material consists of a layered structure and an irregular rock salt structure.

[0052] A preferred embodiment is the positive electrode active material according to the present invention, wherein the layered structure contains Ni.

[0053] A preferred embodiment is a positive electrode active material according to the present invention, in which the irregular rock salt structure contains M'', M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof, preferably M'' is Cr, W, Mo, or a combination thereof, and more preferably M'' is W, Mo, or a combination thereof.

[0054] As will be understood by those skilled in the art, the layered structure [Number] has symmetry and is determined by X-ray diffraction having peaks particularly around 2θ = 17.5 - 20.0° and 2θ = 43.5 - 45.5°. [Number] has a layered structure with symmetry. As will be understood by those skilled in the art, the irregular rock salt structure [Number] has symmetry and is determined by X-ray diffraction having peaks particularly around 2θ = 29.5 - 30.5° and 2θ = 34.5 - 35.5°. [Number] has an irregular rock salt structure with symmetry. As will be understood by those skilled in the art, the positive electrode active material of the present invention can also be empirically determined, for example, by observing peaks around 2θ = 17.5 - 20.0° and 2θ = 43.5 - 45.5° by X-ray diffraction, and has a crystal structure. According to FIG. 6, the XRD pattern of EX3 has peaks around 2θ = 29.5 - 30.5° and 2θ = 34.5 - 35.5°. It has been demonstrated that by increasing the amount of Mo forming Li4MoO5, two different crystal structures are observed by XRD analysis. For substances with a small amount of Mo, the crystal structure can be determined by analyzing not only XRD but also TEM and NMR.

[0055] In certain preferred embodiments, the cathode active material comprises a two-phase structure determined by nuclear magnetic resonance (NMR), preferably 7 Li NMR. More preferred embodiments are the cathode active materials of the present invention wherein the two-phase structure comprises a layered structure and an irregular rock-salt structure. In more preferred embodiments, the two-phase structure consists of a layered structure and an irregular rock-salt structure.

[0056] In certain very preferred embodiments, the layered structure comprises LiNiO2 and the irregular rock-salt structure comprises Li4M 1 O5, wherein M 1 is selected from the group consisting of Cr, Mo, W, Te, and combinations thereof, preferably M 1 is Cr, W, Mo, or a combination thereof, more preferably M 1 is W, Mo, or a combination thereof. In a very preferred embodiment, the irregular rock-salt structure comprises Li4MoO5. In certain very preferred embodiments, the layered structure comprises LiNiO2 and the irregular rock-salt structure comprises Li3M 2 O4, wherein M 2 is selected from the group consisting of V, Nb, Ta, Sb, and combinations thereof, preferably M 2 is V, Nb, Ta, Sb, or a combination thereof, more preferably M 2 is V, Nb, or Ta. In certain very preferred embodiments, the layered structure comprises LiNiO2 and the irregular rock-salt structure comprises Li2M 3 O3, wherein M 3 is selected from the group consisting of Ti, Zr, Hf, Te, and combinations thereof, preferably M 3 is Ti, Zr, Hf, or a combination thereof, more preferably M 3 is Ti, Zr, or Hf.

[0057] In certain very preferred embodiments, the layered structure consists of LiNiO2 and the irregular rock-salt structure consists of Li4M 1 O5, wherein M 1is selected from the group consisting of Cr, Mo, W, Te, and combinations thereof, preferably, M 1 is Cr, W, Mo, or a combination thereof, more preferably, M 1 is W, Mo, or a combination thereof. In certain very preferred embodiments, the layered structure consists of LiNiO2, and the disordered rock salt structure consists of Li3M 2 O4, where M 2 is selected from the group consisting of V, Nb, Ta, Sb, and combinations thereof, preferably, M 2 is V, Nb, Ta, Sb, or a combination thereof, more preferably, M 2 is V, Nb, or Ta. In certain very preferred embodiments, the layered structure consists of LiNiO2, and the disordered rock salt structure consists of Li2M 3 O3, where M 3 is selected from the group consisting of Ti, Zr, Hf, Te, and combinations thereof, preferably, M 3 is Ti, Zr, Hf, or a combination thereof, more preferably, M 3 is Ti, Zr, or Hf.

[0058] In a very preferred embodiment, the disordered rock salt consists of Li4MoO5. As will be understood by those skilled in the art, the 7 Li signal of the layered structure is determined at 600 - 750 ppm, preferably 650 - 725 ppm, more preferably 665 - 685 ppm, and most preferably about 680 ppm. As will be understood by those skilled in the art, the 7 Li signal of the disordered rock salt structure is determined at - 100 - 100 ppm, preferably - 50 - 50 ppm, more preferably - 5 - 5 ppm, and most preferably about 0 ppm.

[0059] In a more preferred embodiment, the layered structure has 7 less than 70.0 mol% 7 Li, preferably less than 60.0 mol% 7 Li, most preferably less than 60.0 mol% 7 Li, based on the total amount of7 less than 50.0 mol% of Li with respect to the total amount of Li, and these are determined by NMR. In a more preferred embodiment, the layered structure is 7 more than 20.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, preferably 7 more than 30.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, most preferably 7 more than 40.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, and these are measured by NMR. In a more preferred embodiment, the layered structure is 20.0 to 70.0 mol% of 7 Li with respect to the total amount of Li in the positive electrode active material, preferably 7 30.0 to 60.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, most preferably 7 40.0 to 50.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, and these are determined by NMR. 7

[0060] In a more preferred embodiment, the disordered rock salt structure is less than 50.0 mol% of Li with respect to the total amount of Li in the positive electrode active material, preferably 7 less than 40.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, most preferably 7 less than 30.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, and these are determined by NMR. In a more preferred embodiment, the disordered rock salt structure is 7 more than 5.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, preferably 7 more than 8.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, most preferably 7 more than 10.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7 Li, and these are determined by NMR. In a more preferred embodiment, the disordered rock salt structure is 7 more than 5.0 mol% of Li with respect to the total amount of Li in the positive electrode active material 7Containing Li, which are determined by NMR. In a more preferred embodiment, the disordered rock salt structure is 5.0 to 50.0 mol% of 7 Li, preferably 7 8.0 to 40.0 mol% of 7 Li, most preferably 7 10.0 to 30.0 mol% of 7 Li, which are determined by NMR.

[0061] As will be understood by those skilled in the art, the relative weight of each contribution of the layered structure or disordered rock salt is obtained from the area of the entire spinning sideband pattern. For example, without being limited to the present invention, the two-phase structure and / or the layered structure and / or the disordered rock salt structure can be measured using a 1.3 mm magic angle spinning (MAS) probe rotating at 62.5 kHz under pure nitrogen gas with a 4.7 T Avance III HD Bruker NMR spectrometer ( 7 77.8 MHz for Li).

[0062] As will be understood by those skilled in the art, the two-phase structure determined by NMR is the same two-phase structure as that determined by TEM. In particular, the layered structure determined by NMR is the same as the layered structure determined by TEM, and the disordered rock salt structure determined by NMR is the same as the disordered rock salt structure determined by TEM.

[0063] In a specific preferred embodiment, the positive electrode active material includes an interfacial structure, preferably an interfacial structure between a layered structure and a disordered rock salt structure, determined by NMR, preferably 7 Li NMR. The interfacial structure includes a Ni-rich rock salt phase, preferably consisting of a Ni-rich rock salt phase. In a more preferred embodiment, the interfacial structure has a 7 Li signal of 300 to 600 ppm, preferably 350 to 550 ppm, most preferably 400 to 500 ppm.

[0064] In a more preferred embodiment, the cathode active material of the present invention has a lattice constant a, where a ≥ 2.8810, preferably a ≥ 2.8815, more preferably a ≥ 2.8820, and the lattice constant a is determined by the Rietveld method. In a more preferred embodiment, the cathode active material of the present invention has a lattice constant a, where a ≤ 2.8860, preferably a ≤ 2.8865, more preferably a ≤ 2.8870, and the lattice constant a is determined by the Rietveld method. In a more preferred embodiment, the cathode active material of the present invention has a lattice constant a, where 2.8810 ≤ a ≤ 2.8870, preferably 2.8815 ≤ a ≤ 2.8865, more preferably 2.8820 ≤ a ≤ 2.8860, and the lattice constant a is determined by the Rietveld method.

[0065] In a more preferred embodiment, the cathode active material of the present invention has a lattice constant c, where c ≥ 14.200, preferably c ≥ 14.210, more preferably c ≥ 14.220, and the lattice constant c is determined by the Rietveld method. In a more preferred embodiment, the cathode active material of the present invention has a lattice constant c, where c ≤ 14.235, preferably c ≤ 14.230, more preferably c ≤ 14.225, and the lattice constant c is determined by the Rietveld method. In a more preferred embodiment, the cathode active material of the present invention has a lattice constant c, where 14.200 ≤ c ≤ 14.235, preferably 14.210 ≤ c ≤ 14.230, more preferably 14.220 ≤ c ≤ 14.225, and the lattice constant c is determined by the Rietveld method.

[0066] In a more preferred embodiment, the cathode active material of the present invention has a ratio of lattice constants c / a ≤ 4.930, preferably c / a ≤ 4.929, more preferably c / a ≤ 4.928, and the lattice constants a and c are determined by the Rietveld method.

[0067] In a more preferred embodiment, the cathode active material of the present invention has a particle size of less than 500 nm, preferably less than 400 nm, more preferably less than 300 nm, and the particle size is determined by SEM.

[0068] In a second aspect, the present invention provides formula (I), Li 1+x M’ 1-x O2(I) [wherein x is in the range of 0 < x < 0.6] provides a positive electrode active material.

[0069] As will be understood by those skilled in the art, all embodiments related to the positive electrode material according to the first aspect of the present invention are equally applicable to the positive electrode according to the second aspect of the present invention.

[0070] Method for manufacturing In a third aspect, the present invention is a method for manufacturing a positive electrode active material, the method comprising the following consecutive steps: Step 1) Dissolving a salt of M’ in a molar ratio in alcohol or water and stirring while heating to obtain a mixture, wherein M’ includes Ni and M’’, and M’’ is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof; Step 2) Drying the mixture at a temperature in the range of 100°C to 150°C; and Step 3) Heating the dried substance at a temperature in the range of 700°C to 800°C. The present invention provides a method including these steps.

[0071] As will be understood by those skilled in the art, all embodiments related to the positive electrode active material according to the first aspect of the present invention and the positive electrode active material according to the second aspect of the present invention are equally applicable to the method for manufacturing the positive electrode active material of the present invention.

[0072] In a preferred embodiment of the present method, during the dissolution of the salt of M’, a lithium source is also dissolved in ethanol or water. Preferably, the lithium source is lithium acetate and / or lithium acetate dihydrate.

[0073] In a preferred embodiment of the present method, the salt of M' includes a nickel salt and a salt of M'', where M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof. Preferably, M'' is Cr, W, Mo, or a combination thereof. More preferably, M'' is W, Mo, or a combination thereof. Most preferably, M'' is Mo. In a specific preferred embodiment, the nickel salt is nickel(II) acetate and / or nickel(II) acetate dihydrate, and the salt of M'' is (NH4)6Mo7O 24 .4H2O.

[0074] In a preferred embodiment of the present method, the alcohol is methanol, ethanol, propanol, butanol, or a combination thereof. Preferably, it is ethanol, propanol, or a combination thereof. Most preferably, it is ethanol.

[0075] In a preferred embodiment of the present method, the salt of M' is uniformly dissolved in alcohol or water.

[0076] A preferred embodiment is a method in which the heating temperature during stirring in step 1) is in the range of 50°C to 150°C, preferably in the range of 75°C to 125°C, and most preferably in the range of 80°C to 100°C.

[0077] A preferred embodiment is a method in which the drying of the mixture in step 2) is carried out in air, preferably in dry air.

[0078] A preferred embodiment is a method in which the mixture in step 2) is dried at a temperature in the range of 100°C to 150°C, preferably in the range of 110°C to 140°C, and more preferably in the range of 115°C to 135°C.

[0079] A preferred embodiment is a method in which the heating of the dried substance in step 3) is in the range of 700°C to 800°C, preferably in the range of 710°C to 790°C, and most preferably in the range of 725°C to 775°C.

[0080] A preferred embodiment is a method in which the heating of the dried substance in step 3) is carried out in an atmosphere containing oxygen, preferably in an atmosphere consisting of oxygen.

[0081] In a highly preferred embodiment of the method for manufacturing, the positive electrode active material is according to the first aspect of the present invention and / or according to the second aspect of the present invention.

[0082] In a fourth aspect, the present invention is a method for manufacturing a positive electrode active material, wherein the positive electrode active material has the chemical formula Li 1+x M’ 1-x O2 [wherein x is in the range of 0 < x < 0.6 and M’ includes Ni and Mo], and the method includes the following consecutive steps: Step 1) Dissolving a salt of M’ having a stoichiometric molar ratio in alcohol or water and stirring while heating to obtain a mixture. Step 2) Drying the mixture at a temperature in the range of 100°C to 150°C, and Step 3) Heating the dried substance at a temperature in the range of 700°C to 800°C.

[0083] As will be understood by those skilled in the art, all embodiments related to the method for manufacturing the positive electrode active material according to the first aspect of the present invention, the positive electrode active material according to the second aspect of the present invention, and the positive electrode active material according to the third aspect of the present invention are equally applicable to the method for manufacturing the positive electrode active material according to the fourth aspect of the present invention.

[0084] In a highly preferred embodiment of the method for manufacturing, the positive electrode active material is according to the first aspect of the present invention and / or according to the second aspect of the present invention.

[0085] Battery In a fifth aspect, the present invention provides a battery including the positive electrode active material of the present invention, particularly the positive electrode active material according to the first aspect of the present invention and / or the positive electrode active material according to the second aspect of the present invention.

[0086] In a preferred embodiment of the present invention, the battery has a DQ1 of 190 mAh / g -1 or higher, preferably 200 mAh / g -1 or higher, more preferably 210 mAh / g -1 or higher. As will be understood by those skilled in the art, DQ1 is the first discharge capacity of the battery.

[0087] In a preferred embodiment of the present invention, the battery has a relative capacity that is higher than 65%, preferably higher than 70%, more preferably higher than 75%, even more preferably higher than 80%, even more preferably higher than 85%, and most preferably higher than 85%. As will be understood by those skilled in the art, the relative capacity is

[0088] [wherein, DQ1 is the first discharge capacity of the battery, and DQ101 is the final discharge capacity after 100 cycles] as defined.

[0089] As demonstrated in the attached examples, the battery of the present invention has no bulk fatigue, which means that the battery maintains an electrochemically stable state during cycling, especially after 2 cycles. A battery containing LiNiO2 as the positive electrode active material exhibits this bulk fatigue due to the formation of a surface irregular rock salt phase that causes mechanical failure. This is characteristic of some inactive Li ions that are electrochemically inaccessible, thereby reducing the capacity. The in-situ XRD pattern of LiNiO2 is the pattern of charged LiNiO2 showing the coexistence of a Li-rich phase and a Li-poor phase due to bulk fatigue, while the pattern of the charged positive electrode active material according to the first aspect of the present invention and / or the positive electrode active material according to the second aspect of the present invention shows only a single phase.

[0090] Use In a sixth aspect, the present invention provides for the use of a positive electrode active material according to the first aspect and / or the second aspect of the present invention in a battery.

[0091] ​A preferred embodiment is the use of a positive electrode active material in a battery for increasing the first discharge capacity of the battery, for increasing the relative capacity of the battery, and / or for improving the electrochemical stability of the battery.

[0092] In a seventh aspect, the present invention provides the use of a battery according to the present invention in any one of a portable computer, a tablet, a mobile phone, an energy storage system, an electric vehicle, or a hybrid electric vehicle, preferably an electric vehicle or a hybrid electric vehicle.

Examples

[0093] Description of test method ICP-OES analysis The amounts of Li, Ni, Mo, W, Mn, and Co in the positive electrode active material powder were measured by inductively coupled plasma (ICP) method using a PerkinElmer NexION 2000 ICP mass spectrometer. A 0.5 mg powder sample was dissolved in 1 mL of aqua regia in a 100 mL volumetric flask. Then, distilled water was added to the volumetric flask up to the 100 mL mark and thoroughly homogenized and diluted. The diluted solution was used for ICP-OES measurement. The measured contents of Ni, Mo, W, Mn, Co and Q (contents a, b, c, d and e respectively) are expressed as mol% of the total of these contents.

[0094] Analysis by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) For the electron microscope images, measurements were performed using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The positive electrode active material powder was ground in a mortar in dimethyl carbonate, and droplets of the suspension were deposited on a copper TEM grid with a perforated carbon support layer prepared inside an Ar-filled glove box. The sample was transferred to the TEM column using a Gatan vacuum transfer holder that completely avoided contact with air and moisture. Electron diffraction (ED) patterns, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images, and energy-dispersive X-ray spectra (EDS) were collected using a probe-corrected Titan Themis Z electron microscope operating at 200 kV and equipped with a Super-X EDX detector.

[0095] 7 Li nuclear magnetic resonance (NMR) analysis To observe the chemical structure of the prepared substances, a 4.7 T Avance III HD Bruker NMR spectrometer ( 7 77.8 MHz for Li) was used, and solid-state NMR was measured using a 1.3 mm magic angle spinning (MAS) probe that spins at 62.5 kHz under pure nitrogen gas. In the absence of temperature control, the temperature inside the rotor is expected to reach approximately 50 °C. All 7 Li NMR experiments were recorded using a rotor-synchronized Hahn echo sequence, the 90° pulse was set to 1.1 μs, and the chemical shift was referenced to 0 ppm (corresponding to a B1 magnetic field strength of 227 kHz) using liquid 7 LiCl in water. The T1 relaxation time was measured using a saturation recovery experiment, and 20 x 90° pulses separated by a 1 millisecond delay for saturation were used. The T1 behavior is close to that of paramagnetic Ni 3+ ions 7As expected for Li spin, the left peak (about 600 - 850 ppm) was found to be single exponential, and the T1 value was about 2 - 5 milliseconds. For the diamagnetic part, T1 relaxation was found to be multi - exponential, and at least two components were observed: a slow relaxation component with a T1 value of 1 - 1.5 seconds and a fast relaxation component with a T1 value of 5 - 30 milliseconds. This is, firstly, expected from the fact that the spinning sidebands from the LiNiO2 peak are close to 0 ppm contribution (mapped to the red on the right near - 120 ppm). Secondly, since the diamagnetic contribution is made by lithium in molybdenum - rich domains embedded in the LiNiO2 phase, lithium ions closer to the interface exhibit shorter relaxation times. Therefore, in order to ensure proper quantification of the diamagnetic contribution, all 7 Li spectra were recorded using a relaxation delay of 5 - 10 seconds, and at least 1024 transients were recorded to ensure a sufficient signal - to - noise ratio. The spectra were deconvolved with DMFit using the minimum number of necessary Gaussian - Lorentzian spinning sideband patterns (up to 5 spinning sidebands) characterized by Gaussian / Lorentzian ratio, position (ppm), width (ppm), and intensity, and all of these were fitted by the program. The spinning sideband intensities were fitted independently, and the relative weight of each contribution was obtained from the area of the entire spinning sideband pattern. Preferably, special care should be taken to measure the NMR spectrum of the freshly obtained sample with minimal contact with residual moisture inside the glove box or inside the NMR spectrometer.

[0096] X - ray diffraction (XRD) analysis The XRD pattern was obtained using a Cu Kα radiation source (λ Kα1 = 1.54056 Å, λ Kα2It was obtained by a laboratory X-ray diffractometer (BRUKER D8 Advance) equipped with a Lynxeye XE detector (λ = 1.54439 Å). A self-made airtight cell with a Be window was used for in situ XRD experiments, and for electrochemistry, it was carried out in synchronization with data acquisition. All Rietveld refinements of the XRD patterns were performed using the Full Prof program.

[0097] Scanning electron microscope (SEM) analysis SEM images were obtained with a FEI Magellan scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy (EDX) detector from Oxford Instruments. EDX was performed at an accelerating voltage of 20 kV.

[0098] Electrochemical tests The positive electrode for the electrochemical test was composed of 70 wt% of the positive electrode active material, 20 wt% of carbon (Super P), and 10 wt% of PTFE. An OEMS cell was used for the electrochemical test. A half-cell was constructed using 150 μL of LP57 + 2% VC electrolyte, a Li foil as the anode, and one GF / D glass fiber separator. To stabilize the background signal, an operando protocol of pausing the cell 4 hours before and 12 hours after the complete electrochemistry was used to collect quantitative gas generation data on the m / z channels of 32 (O2) and 44 (CO2). The electrochemical cell was cycled 101 times at a rate of C / 10 (20 mA / g) at room temperature between 2.0 and 4.3 V.

[0099] The initial discharge capacity (DQ1) and the final discharge capacity (DQ101) after 100 cycles were measured, and the ratio of DQ1 to DQ101 was calculated to compare the electrochemical stability of the electrodes containing the substances produced in the examples and comparative examples. The relative capacity (%) is expressed as % as follows:

[0100]

Equation

[0101] Examples / Comparative Examples Example 1 (EX1) The positive electrode active material is obtained through the following steps: 1) Preparation of mixed metal solution: 2.2707 grams of Li(CH3COO).2H2O and 4.4791 grams of Ni(CH3COO)2.4H2O are uniformly dissolved in 80 mL of ethanol (purity over 98%). 0.1412 grams of (NH4)6Mo7O 24 .4H2O is uniformly dissolved in 20 mL of distilled water. The aqueous solution containing ammonium heptamolybdate is added to the ethanol - acetic acid solution containing lithium ions and nickel ions to obtain a mixed metal solution. 2) Preparation of gel - like mixture: The mixed metal solution obtained in step 1) is stirred and heated at 80 °C simultaneously to obtain a gel - like mixture. 3) Drying and pulverization: The gel - like mixture obtained in step 2) is dried at 120 °C for 8 hours under an oxygen stream, and the dried substance is pulverized. 4) Heating: The pulverized substance is heated at 750 °C for 8 hours under an oxygen stream to obtain EX1.

[0102] Example 2 (EX2) Except for preparing the mixed metal solution in step 1) using 2.3350 grams of Li(CH3COO).2H2O, 4.2303 grams of Ni(CH3COO)2.4H2O, and 0.2119 grams of (NH4)6Mo7O 24 .4H2O, the positive electrode active material EX2 is obtained through the same process as in Example 1.

[0103] Example 3 (EX3) Except for preparing the mixed metal solution in step 1) using 2.3993 grams of Li(CH3COO).2H2O, 3.9814 grams of Ni(CH3COO)2.4H2O, and 0.2825 grams of (NH4)6Mo7O 24 .4H2O, the positive electrode active material EX3 is obtained through the same process as in Example 1.

[0104] Comparative Example 1 (CEX1) The positive electrode active material CEX1 is obtained through the following steps: 1) Preparation of mixed metal solution: 2.1422 grams of Li(CH3COO).2H2O and 4.9768 grams of Ni(CH3COO)2.4H2O are uniformly dissolved in 80 mL of ethanol (purity over 98%) to obtain a mixed metal solution. 2) Preparation of gel-like mixture: The mixed metal solution obtained in step 1) is stirred and simultaneously heated at 80 °C to obtain a gel-like mixture. 3) Drying and grinding: The gel-like mixture obtained in step 2) is dried at 120 °C for 8 hours under an oxygen stream, and the dried substance is ground. 4) Heating: The ground substance is heated at 750 °C for 8 hours under an oxygen stream to obtain CEX1.

[0105] Comparative Example 2 (CEX2) Using 2.1422 grams of Li(CH3COO).2H2O, 4.6782 grams of Ni(CH3COO)2.4H2O, and 0.2119 grams of (NH4)6Mo7O 24 .4H2O, except for preparing the mixed metal solution in step 1), the same process as in Example 1 is followed to obtain the cathode active material CEX2.

[0106] Comparative Example 3 (CEX3) Using 2.1422 grams of Li(CH3COO).2H2O, 4.5787 grams of Ni(CH3COO)2.4H2O, and 0.2825 grams of (NH4)6Mo7O 24 .4H2O, except for preparing the mixed metal solution in step 1), the same process as in Example 1 is followed to obtain the cathode active material CEX3.

[0107] The molar contents of the components of EX1, EX2, EX3, CEX1, CEX2, and CEX3 are analyzed by ICP-OES and summarized in Table 1. Also, the results of the electrochemical tests used in the examples / comparative examples are summarized in Table 1.

[0108]

Table 1

[0109] By analyzing the results of ICP-OES, it was demonstrated that the cathode active materials EX1, EX2, and EX3 prepared in Examples 1, 2, and 3, respectively, were successfully synthesized as Li-rich materials. From the observation of HAADF-STEM images, the cathode active materials EX1, EX2, and EX3 contain two types of structures: a layered structure and an irregular structure. Figure 2 is the HAADF-STEM image of EX2 as a representative of the two-phase structure of materials EX1, EX2, and EX3. When observing the TEM-EDS mapping images, Mo and Ni were unevenly distributed. This suggests the existence of two types of domains: a LiNiO2-rich domain and a Li4MoO5-rich domain. To confirm the two-phase twin crystal structure, 7 When the Li NMR spectrum was analyzed, there were peaks shifted near 0 ppm indicating the LiNiO2-rich domain and peaks shifted near 680 ppm indicating the Li4MoO5-rich domain. By increasing the amount of Mo, the peak near 0 ppm became higher as described in Figure 1.

[0110] Table 2 shows the lattice constants a and c of EX1 to EX3 and CEX1 determined by the Rietveld method.

[0111]

Table 2

[0112] Figure 4 shows a comparison of in-situ XRD generation between CEX1 and EX2. The pattern of charged CEX1 shows the splitting of the (003) peak due to the coexistence of the Li-rich phase and the Li-poor phase caused by bulk fatigue, while the pattern of charged EX2 shows only a single phase. Figure 5 shows the in-situ XRD patterns (16 - 23°) at the end of charging during the second cycle (2C 4.3V) for CEX1 and EX2, respectively. The pattern of charged LiNiO2 shows split peaks due to the coexistence of the Li-rich phase and the Li-poor phase caused by bulk fatigue, while the pattern of charged Li 1.09 Ni 0.85 Mo 0.06 NiMoO2 shows only a single phase.

[0113] Table 3 shows 7 the quantification of different phases of LiNiO2 and Li4MoO5 determined by Li NMR.

[0114] [Table 3]

[0115] Figure 6 shows the XRD patterns of EX1 to EX3 and CEX1, which support the synthesis of each compound.

Claims

1. A positive electrode active material including a layered structure and an irregular rock salt structure, wherein the positive electrode material contains Li and M', has an Li / M' ratio z (mol / mol), and 1.05 ≤ z ≤ 1.27, and M' is an element other than Li and O, the positive electrode active material.

2. The positive electrode active material according to Claim 1, wherein 1.1 ≤ z ≤ 1.27, preferably 1.15 ≤ z ≤ 1.27, more preferably 1.2 ≤ z ≤ 1.

22.

3. Formula (I), Li １＋ｘ M’ １－ｘ O ２ (I) [wherein x is in the range of 0 < x < 0.6, M' is selected from the group consisting of Ni, Co, Mn, Q, M'', and combinations thereof, Q is an element other than Li, O, Ni, Co, Mn, and M'', and M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof] represented by the positive electrode active material according to Claim 1.

4. The positive electrode active material according to Claim 1, wherein M'' is Cr, W, Mo, or a combination thereof, preferably M'' is W, Mo, or a combination thereof, and most preferably M'' is Mo.

5. The positive electrode active material according to Claim 2, wherein x is in the range of 0.01 ≤ x ≤ 0.12, preferably 0.02 ≤ x ≤ 0.11, more preferably 0.03 ≤ x ≤ 0.

10.

6. The positive electrode active material according to Claim 2, wherein Q is selected from the group consisting of Al, B, Ba, Ca, Fe, Mg, S, Si, Sr, Y, Zn, and combinations thereof, preferably selected from the group consisting of Al, B, S, Si, Y, and combinations thereof.

7. The positive electrode active material according to Claim 2, wherein Q has a content e of 0.0 ≤ e ≤ 2.0 mol% with respect to M'.

8. Formula (II), Li １＋ｙ Ni （３－５ｙ）／３ M’’ ２ｙ／３ O ２ (II) [wherein 0 < y ≤ 0.6 with respect to the total amount of Li, Ni, and M'', preferably 0.01 ≤ y ≤ 0.4 with respect to the total amount of Li, Ni, and M'', more preferably 0.02 ≤ y ≤ 0.2 with respect to the total amount of Li, Ni, and M''] represented by the positive electrode active material according to Claim 1.

9. The positive electrode active material according to Claim 8, wherein y is in the range of 0.01 ≤ y ≤ 0.12 with respect to the total amount of Li, Ni, and M'', preferably 0.02 ≤ y ≤ 0.11 with respect to the total amount of Li, Ni, and M'', more preferably 0.03 ≤ y ≤ 0.1 with respect to the total amount of Li, Ni, and M''.

10. Formula (II) h, Li １＋ｙｈ Ni （３－５ｙｈ）／３ Mo ２ｙｈ／３ O ２ (II) h [wherein, yh satisfies 0.01 ≦ yh ≦ 0.12 with respect to the total amount of Li, Ni, and Mo, preferably 0.02 ≦ yh ≦ 0.11 with respect to the total amount of Li, Ni, and Mo, and more preferably 0.03 ≦ yh ≦ 0.1 with respect to the total amount of Li, Ni, and Mo], the positive electrode active material according to claim 9.

11. The layered structure contains LiNiO ２ and preferably consists of LiNiO ２ The cathode active material according to claim 1.

12. An irregular rock salt structure contains Li ４ MoO ５ and preferably consists of Li ４ MoO ５ The positive electrode active material according to claim 1.

13. The positive electrode active material according to claim 1, wherein the layered structure has peaks in the vicinity of 2θ = 17.5 to 20.0° and 2θ = 43.5 to 45.5° as determined by X-ray diffraction.

14. The positive electrode active material according to claim 1, wherein the disordered rock salt structure has peaks in the vicinity of 2θ = 29.5 to 30.5° and 2θ = 34.5 to 35.5° as determined by X-ray diffraction.

15. Of the above-mentioned layered structure ７ The Li signal is ７ The positive electrode active material according to claim 1, which is determined by Li NMR to be 600 to 750 ppm, preferably 650 to 725 ppm, more preferably 665 to 685 ppm, and most preferably about 680 ppm.

16. The layered structure is ７ Li, which is determined by Li NMR, and is 20.0 to 70.0 mol% based on the total amount of Li in the positive electrode active material ７ Li, preferably ７ 30.0 to 60.0 mol% based on the total amount of Li in the positive electrode active material ７ Li, most preferably ７ 40.0 to 50.0 mol% based on the total amount of Li in the positive electrode active material ７ The positive electrode active material according to claim 1, containing Li.

17. of the irregular rock salt structure ７ The Li signal is ７ The positive electrode active material according to claim 1, determined by Li NMR to be 100 to 100 ppm, preferably -50 to 50 ppm, more preferably -5 to 5 ppm, and most preferably about 0 ppm.

18. The layered structure contains 5.0 to 50.0 mol% of Li, determined by NMR, based on the total amount of Li in the positive electrode active material. ７ Li, preferably ７ 8.0 to 40.0 mol% of Li, based on the total amount of Li in the positive electrode active material. ７ Li, most preferably ７ 10.0 to 30.0 mol% of Li, based on the total amount of Li in the positive electrode active material. ７ The positive electrode active material according to claim 1, which contains Li.

19. A method for producing a positive electrode active material, preferably the positive electrode active material according to any one of claims 1 to 18, wherein the method comprises the following consecutive steps: Step 1) A step of dissolving a salt of M' in a molar ratio in alcohol or water and stirring while heating to obtain a mixture, wherein M' contains Ni and M'', and M'' is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Te, Sb, and combinations thereof. Step 2) A step of drying the mixture at a temperature in the range of 100°C to 150°C, and Step 3) A step of heating the dried substance at a temperature in the range of 700°C to 800°C.

20. Use of the positive electrode active material according to any one of claims 1 to 18 in a battery.

21. A battery comprising the positive electrode active material according to any one of claims 1 to 18.

22. Use of the battery according to claim 21 in any one of a portable computer, a tablet, a mobile phone, an energy storage system, an electric vehicle, or a hybrid electric vehicle, preferably an electric vehicle or a hybrid electric vehicle.

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