Composite positive electrode active material particle for lithium ion battery, positive electrode active material layer, lithium ion battery, and method for manufacturing composite positive electrode active material particle for lithium ion battery

Abstract

To provide a composite positive electrode active material particle for a lithium ion battery that can suppress a decrease in capacity after an initial charge and also suppress a decrease in capacity when repeatedly charged and discharged.SOLUTION: As shown in FIG. 1, a composite positive electrode active material particle 112 for a lithium-ion battery according to the present disclosure includes a positive electrode active material 1122, and lithium alloy particles 1124 having a lithium alloying potential of 0.5 V (vs Li / Li+) or higher, and / or metal particles 1126 generated by the desorption of lithium from the lithium alloy. The lithium alloy particles 1124 or the metal particles 1126 are dispersed within the positive electrode active material 1122.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to composite positive electrode active material particles for lithium ion batteries, a positive electrode active material layer, and a lithium ion battery, as well as a method for producing composite positive electrode active material particles for lithium ion batteries. [Background technology]

[0002] Conventionally, in order to increase the capacity of lithium ion batteries, the active materials have been improved.

[0003] Patent Document 1 discloses an electrode for use in a non-aqueous electrolyte secondary battery. 2 The specific surface area measured by the adsorption method is 3.3 m 2 / g or more and 4.4m 2 / g or less. The positive electrode active material of this electrode has a DBP oil absorption of 30 ml / 100 g or more and 47 ml / 100 g or less. The positive electrode density is 1.8 g / cm 3 More than 2.2g / cm 3 The details are as follows: Patent Document 1 discloses that the capacity of the negative electrode is increased by using a lithium (Li) alloy as an active material.

[0004] In addition, nickel-cobalt-manganese (NCM) lithium oxide is widely used as the positive electrode active material, and improvements to its composition are also being investigated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-010991 A Summary of the Invention [Problem to be solved by the invention]

[0006] When using conventional electrodes such as the electrode of Patent Document 1, a significant decrease in capacity was observed after initial charging. In addition, batteries are also required to have good cycle characteristics, that is, to suppress the decrease in capacity when repeatedly charged and discharged.

[0007] Therefore, the present disclosure provides composite positive electrode active material particles for lithium ion batteries that can suppress the decrease in capacity after initial charging and also suppress the decrease in capacity when repeatedly charged and discharged. [Means for solving the problem]

[0008] As a result of intensive research, the present inventors have found that the above problems can be solved by the following means, and have completed the present disclosure. That is, the present disclosure is as follows: Aspect 1: A composite positive electrode active material particle for a lithium ion battery, comprising: A positive electrode active material, and Lithium alloying potential is 0.5V (vs Li / Li + ) or more, and / or metal particles produced by desorption of lithium from the lithium alloy particles. It contains The lithium alloy particles or the metal particles are dispersed in the positive electrode active material. Composite positive electrode active material particles for lithium-ion batteries. <Aspect 2> The lithium alloy particles are Li 3 Bi, Li 3 2. The composite positive electrode active material particle for a lithium ion battery of embodiment 1, wherein the active material is selected from the group consisting of Sb, and LiSn. Aspect 3: The composite positive electrode active material particle for a lithium ion battery according to Aspect 1 or 2, wherein the positive electrode active material is an NCM lithium oxide. A positive electrode active material layer comprising the composite positive electrode active material particle for a lithium ion battery according to any one of Aspects 1 to 3. A lithium ion battery comprising the positive electrode active material layer according to Aspect 4. Aspect 6: A positive electrode active material and a lithium alloying potential of 0.5V (vs Li / Li + ) or more. preparing a positive electrode precursor layer containing at least the composite positive electrode active material particle precursor for a lithium ion battery; Obtaining a lithium ion battery precursor having the positive electrode precursor layer, a separator or solid electrolyte layer, and a negative electrode active material layer in this order and impregnated with an electrolytic solution; and performing an initial charge on the lithium ion battery precursor to convert the positive electrode precursor layer into a positive electrode active material layer; A method for producing a lithium ion battery, comprising: Effect of the Invention

[0009] According to the present disclosure, it is possible to provide composite positive electrode active material particles for lithium ion batteries that can suppress the decrease in capacity after initial charging and also suppress the decrease in capacity when repeatedly charged and discharged. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a composite positive electrode active material particle for a lithium ion battery according to the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram of a lithium ion battery of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <<Composite positive electrode active material particles for lithium-ion batteries>> As shown in FIG. 1, the composite positive electrode active material particle 112 for a lithium ion battery according to the present disclosure has Positive electrode active material 1122, and Lithium alloying potential is 0.5V (vs Li / Li + ) or more, and / or metal particles 1126 produced by desorption of lithium from the lithium alloy. It contains The lithium alloy particles 1124 or the metal particles 1126 are dispersed in the positive electrode active material 1122 .

[0012] The present inventors have found that the cause of the decrease in battery capacity described in Patent Document 1 is that lithium supplied in the initial positive electrode active material is consumed due to the formation of a solid electrolyte interphase (SEI) in the negative electrode during the first charge.

[0013] In response to this, the present inventors have found that the capacity can be improved by obtaining a lithium ion battery by using the above-mentioned composite positive electrode active material particles for lithium ion batteries in the positive electrode precursor layer. Without wishing to be bound by theory, this is believed to be because lithium from the lithium alloy in the positive electrode precursor layer is released during the first charge and becomes lithium consumed in the formation of the SEI in the negative electrode, thereby preventing the lithium in the positive electrode active material from being consumed in the formation of the SEI. In addition, when the lithium alloying potential of the lithium alloy is 0.5 V (vs Li / Li + ) or more, it is believed that the occurrence of an electrochemical reaction inside the positive electrode precursor before the first charge can be suppressed.

[0014] On the other hand, when the lithium alloy particles are used as they are, there is a problem that the cycle characteristics are not good, and when the battery is repeatedly charged and discharged, the capacity may be significantly reduced after a small number of charge and discharge cycles. The present inventors have found that the cause of this is that the metal constituting the lithium alloy particles becomes a locally high concentration of metal ions when it is oxidized and dissolved during charging, and these ions are precipitated in a concentrated manner in one place on the negative electrode, causing resistance.

[0015] In response to this, the present inventors have found that by dispersing lithium alloy particles in the positive electrode active material, concentrated precipitation of metal in the negative electrode can be suppressed, thereby solving the above problem. Without wishing to be bound by theory, this is believed to be because, in the composite positive electrode active material particles for lithium ion batteries of the present disclosure, lithium passes through the active material and moves to the negative electrode upon charging, while the metal particles generated by the desorption of lithium remain within the active material.

[0016] In other words, the metal particles of the composite positive electrode active material particles for lithium-ion batteries of the present disclosure are formed by dissociating lithium from the lithium alloy particles dispersed in the positive electrode active material after initial charging, so that at least a portion of the lithium alloy particles become metal particles.

[0017] Each component of the present disclosure will be described below.

[0018] <Cathode active material> As the positive electrode active material, any positive electrode active material can be used, and is not particularly limited. For example, a lithium-containing oxide can be used.

[0019] The lithium-containing oxide as the positive electrode active material is not particularly limited, and may be, for example, one that contains at least Li, at least one transition metal element selected from Co, Ni, and Mn, and O. Examples of such lithium-containing oxides include lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), and nickel-cobalt-manganese (NCM) lithium oxides, in which some of these elements are replaced by other elements, can be used. NCM lithium oxides are generally Li a Mn x Ni y Co z O 2±δIt is represented by the general formula (0 < a ≤ 1.5, 0 ≤ x ≤ 1.5, 0 ≤ y ≤ 1.5, 0 ≤ z ≤ 1.5, 0 < δ(=x + y + z) < 1.5), and for example, LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) etc. can be used. The lithium-containing oxide as the positive electrode active material may have, for example, an O 2 -type structure, or an O 3 -type structure, or may have a crystal structure other than these. As the positive electrode active material, only one kind may be used alone, or two or more kinds may be used in combination.

[0020] 〈Lithium alloy particles〉 The lithium alloy particles are lithium alloy particles having a lithium alloying potential of 0.5 V (vs Li / Li + ) or more.

[0021] The lithium alloying potential of the lithium alloy particles may be 0.6 V (vs Li / Li + ) or more, 0.7 V (vs Li / Li + ) or more, or 0.8 V (vs Li / Li + ) or more, and may also be 1.5 V (vs Li / Li + ) or less, 1.4 V (vs Li / Li + ) or less, 1.3 V (vs Li / Li + ) or less, 1.2 V (vs Li / Li + ) or less, 1.1 V (vs Li / Li + ) or less, 1.0 V (vs Li / Li + ) or less.

[0022] Here, the lithium alloying potential (vs Li / Li + ) is the electrode potential of the electrode reaction of formula (1), and is expressed based on the electrode potential of lithium in the following formula (2): xLi + +M+xe - ←→ Li x M (1) Li ++e - ←→ Li (2)

[0023] This lithium alloying potential (vs Li / Li + ) can be measured as the single electrode potential obtained when the alloy is immersed in a salt solution of lithium.

[0024] Such lithium alloy particles include, for example, Li 3 Bi, Li 3 Sb, LiSn, and the like can be used.

[0025] <Metal particles> The metal particles of the composite positive electrode active material particles for lithium ion batteries according to the present disclosure are metal particles produced by desorption of lithium from the lithium alloy particles described above.

[0026] As such metal particles, for example, bismuth particles, antimony particles, tin particles, and the like can be used.

[0027] 《Cathode active material layer》 The positive electrode active material layer contains the above-mentioned composite positive electrode active material particles for lithium ion batteries. The positive electrode active material layer may also contain other materials as desired. Examples of the other materials include a conductive assistant and a binder.

[0028] <Conductive assistant> The conductive assistant optionally contained in the positive electrode precursor layer may be a known conductive assistant used in lithium ion batteries. Specifically, carbon materials such as Ketjen Black (KB), vapor grown carbon fiber (VGCF), acetylene black (AB), carbon nanotube (CNT), carbon nanofiber (CNF), carbon black, coke, graphite, etc. may be used. Alternatively, metal materials capable of withstanding the environment during use of the battery may be used. As the conductive assistant, only one type may be used alone, or two or more types may be used in combination. The conductive assistant may be in various forms such as powder and fiber. The amount of the conductive assistant contained in the positive electrode active material layer is not particularly limited.

[0029] <binder> The binder optionally contained in the positive electrode precursor layer may be any binder known to be used in lithium ion batteries. For example, styrene butadiene rubber (SBR)-based binder, carboxymethyl cellulose (CMC)-based binder, acrylonitrile butadiene rubber (ABR)-based binder, butadiene rubber (BR)-based binder, polyvinylidene fluoride (PVDF)-based binder, polytetrafluoroethylene (PTFE)-based binder, etc. may be used. Only one type of binder may be used alone, or two or more types may be used in combination. The amount of binder contained in the positive electrode active material layer is not particularly limited.

[0030] Lithium-ion battery The lithium ion battery of the present disclosure comprises: The positive electrode active material layer, the separator or solid electrolyte layer, and the negative electrode active material layer are included.

[0031] FIG. 1 is a schematic diagram showing a configuration of a lithium-ion battery 100 according to one embodiment of the present disclosure. As shown in FIG. 1, the lithium-ion battery 100 may include a positive electrode 10, a separator 20, and a negative electrode 30. The positive electrode 10 may include a positive electrode active material layer 11 and a positive electrode current collector layer 12, and the negative electrode 30 may include a negative electrode active material layer 31 and a negative electrode current collector layer 32. In this case, the positive electrode active material layer 11 may include the above-mentioned positive electrode active material. Although not shown, an electrolyte may be included in the positive electrode active material layer 11 and the negative electrode active material layer 31.

[0032] Additionally, if the lithium ion battery of the present disclosure is a solid state battery, the lithium ion battery of the present disclosure may have a solid electrolyte layer present in place of separator 20.

[0033] Each component of the lithium-ion battery of the present disclosure is described below.

[0034] <Positive electrode current collector layer> The positive electrode current collector layer may be made of a known metal that can be used as a positive electrode current collector for a lithium ion battery. Examples of such metals include metal materials containing at least one element selected from the group consisting of Cu, Ni, Al, V, Au, Pt, Mg, Fe, Ti, Pb, Co, Cr, Zn, Ge, In, Sn, and Zr. The form of the positive electrode current collector is not particularly limited. It may take various forms such as a foil, a mesh, or a porous form. The above metal may be vapor-deposited or plated on the surface of a substrate.

[0035] <Separator> The separator may be a known separator used in lithium ion batteries. For example, the separator may be made of a resin such as polyethylene (PE), polypropylene (PP), polyester, or polyamide. The separator may have a single layer structure or a multi-layer structure. As the multi-layer separator, for example, a multi-layer separator made of the above resin, for example, a separator with a two-layer structure of PE / PP, or a separator with a three-layer structure of PP / PE / PP or PE / PP / PE, etc. may be used. The separator may be made of a nonwoven fabric such as a cellulose nonwoven fabric, a resin nonwoven fabric, or a glass fiber nonwoven fabric. The thickness of the separator is not particularly limited, and may be, for example, 5 μm or more and 1 mm or less.

[0036] <Negative electrode active material layer> The negative electrode active material layer contains a negative electrode active material. The negative electrode active material layer may contain other optional components. Examples of the other components include a conductive assistant and a binder. For the conductive assistant and the binder, the description of the positive electrode active material layer can be referred to.

[0037] <Negative electrode active material layer: negative electrode active material> As the negative electrode active material, various materials having a potential (charge / discharge potential) for absorbing and releasing ions that is lower than the above-mentioned positive electrode active material may be used. As the negative electrode active material, for example, silicon-based active materials such as Si, Si alloys, and silicon oxide; carbon-based active materials such as graphite, graphite, and hard carbon; various oxide-based active materials such as lithium titanate; metallic lithium, lithium alloys, and the like may be used. As the negative electrode active material, only one type may be used alone, or two or more types may be used in combination.

[0038] <Negative electrode current collector layer> The negative electrode current collector layer may be made of a known metal that can be used as a negative electrode current collector for a lithium ion battery. Such a metal may be, for example, a metal material containing at least one element selected from the group consisting of Cu, Ni, Al, V, Au, Pt, Mg, Fe, Ti, Pb, Co, Cr, Zn, Ge, In, Sn, and Zr. The form of the negative electrode current collector layer is not particularly limited, and may be in various forms such as a foil, a mesh, or a porous form. The negative electrode current collector layer may be a layer in which the above-mentioned metal is plated or vapor-deposited on the surface of a substrate made of any material. The surface of the negative electrode current collector layer may be coated with a carbon material or the like.

[0039] <Nonaqueous electrolyte> The non-aqueous electrolyte may contain a non-aqueous solvent and an electrolyte. The electrolyte may contain alkali metal ions, such as lithium ions, as carrier ions.

[0040] The non-aqueous solvent may be a solvent other than water, for example, an organic solvent. As the organic solvent, for example, a carbonate solvent such as ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), fluoroethylene carbonate (FEC) or the like may be used. These organic solvents may be used alone or in combination.

[0041] The electrolyte is not particularly limited and may be, for example, a lithium salt. Examples of the lithium salt include LiPF6 etc. can be used.

[0042] <Solid electrolyte layer> The solid electrolyte layer may contain a solid electrolyte.

[0043] The material of the solid electrolyte is not particularly limited, and any material that can be used as a solid electrolyte for use in a lithium ion battery can be used. For example, the solid electrolyte may be, but is not limited to, a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte. In addition, one type of these solid electrolytes may be used alone, or two or more types may be used in combination.

[0044] As the sulfide solid electrolyte, any sulfide solid electrolyte can be used. Specifically, the sulfide solid electrolyte can be, for example, Li 2 SP 2 S 5 , Li 2 S-SiS 2 , LiI-Li 2 S-SiS 2 , LiI-Si 2 SP 2 S 5 , Li 2 SP 2 S 5 -LiI-LiBr, LiI-Li 2 SP 2 S 5 , LiI-Li 2 SP 2 O 5 , LiI-Li 3 PO 4 -P 2 S 5 , Li 2 SP 2 S 5 -GeS 2 Examples of sulfide solid electrolytes include those mentioned above.

[0045] As an oxide solid electrolyte, for example, Li 7 La 3 Zr 2 O12、 Li 7-x La 3 Zr 1-x Nb x O 12、 Li 7-3x La 3 Zr 2 Al x O 12 , Li 3x La 2 / 3-x TiO 3 , Li 1+x Al x Ti 2-x (PO 4 ) 3 , Li 1+x Al x Ge 2-x (PO 4 ) 3 , Li 3 PO 4 , or Li 3+x PO 4-x N x (LiPON), etc., but are not limited to these. These may be amorphous or crystalline.

[0046] Examples of the polymer electrolyte include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0047] <<How lithium-ion batteries are manufactured>> The disclosed method for obtaining a lithium ion battery comprises: A positive electrode active material and a lithium alloying potential dispersed in the positive electrode active material of 0.5 V (vs Li / Li + ) or more. preparing a positive electrode precursor layer containing at least the composite positive electrode active material particle precursor for a lithium ion battery; Obtaining a lithium ion battery precursor having the positive electrode precursor layer, a separator or solid electrolyte layer, and a negative electrode active material layer in this order and impregnated with an electrolytic solution; and performing an initial charge on the lithium ion battery precursor to convert the positive electrode precursor layer into a positive electrode active material layer; Includes.

[0048] Each step of the method of the present disclosure is described below.

[0049] <Preparation of composite positive electrode active material particle precursor for lithium ion batteries> The composite positive electrode active material particle precursor for a lithium ion battery is a positive electrode active material and / or a lithium alloying potential of 0.5V (vs Li / Li + ) or more.

[0050] The preparation of the composite positive electrode active material particle precursor for a lithium ion battery can, in one embodiment, be carried out by a method that includes: grinding the lithium alloy particles in an inert environment; dispersing lithium alloy particles in a molten cathode active material and cooling and solidifying to form a precursor block; and The cooled precursor block is pulverized to obtain a composite positive electrode active material particle precursor for a lithium ion battery.

[0051] In another embodiment, the preparation of a composite positive electrode active material particle precursor for a lithium ion battery can be performed by a method including: grinding the lithium alloy particles in an inert environment; dispersing lithium alloy particles in a molten material for obtaining a positive electrode active material, and then cooling and solidifying the material to prepare a precursor block; and grinding the cooled precursor block to obtain particles having lithium alloy particles dispersed in one material; mixing and reacting the particles with the remaining materials for obtaining a positive electrode active material to obtain a composite positive electrode active material particle precursor for a lithium ion battery;

[0052] As a material for obtaining the positive electrode active material, for example, hydroxides, oxides, carbonates, etc. of the metals constituting the positive electrode active material can be used.

[0053] <Preparation of Positive Electrode Precursor Layer> The positive electrode precursor layer contains at least a composite positive electrode active material particle precursor for a lithium ion battery. The positive electrode precursor layer may also contain other optional materials, such as a conductive assistant and a binder.

[0054] The positive electrode precursor layer can be prepared by mixing the respective materials constituting the layer and applying the mixture.

[0055] Preparation of Lithium-Ion Battery Precursor The lithium ion battery precursor has a positive electrode precursor layer, a separator or solid electrolyte layer, and a negative electrode active material layer in this order, and is impregnated with a non-aqueous electrolyte solution. This lithium ion battery precursor may be produced by a known method.

[0056] The lithium ion battery precursor may further include a positive electrode current collector layer and a negative electrode current collector layer.

[0057] For each component of the lithium ion battery precursor, reference can be made to the description of the lithium ion battery.

[0058] <Preparation of Positive Electrode Active Material Layer> The positive electrode active material layer is prepared by initially charging the lithium ion battery precursor to convert the positive electrode precursor layer into a positive electrode active material layer. This causes at least a portion of the lithium in the lithium alloy particles in the composite positive electrode active material particle precursor for lithium ion batteries to be released to generate metal particles. As a result, the composite positive electrode active material particle precursor for lithium ion batteries becomes the above-mentioned composite positive electrode active material particle for lithium ion batteries, i.e., the composite positive electrode active material particle for lithium ion batteries in which the lithium alloy particles or metal particles are dispersed in the positive electrode active material.

[0059] By initially charging the lithium ion battery precursor having the positive electrode precursor layer, the lithium in the lithium alloy particles is consumed to form the SEI in the negative electrode. As a result, the lithium alloy particles are converted to Li 3 Bi and Li 3 When at least one type of Sb is contained, the resulting positive electrode active material layer contains at least one type of bismuth single particle and antimony single particle.

[0060] The initial charging conditions may be known conditions. EXAMPLES

[0061] The present disclosure will be specifically described with reference to examples and comparative examples, but the present disclosure is not limited thereto.

[0062] 《Making a lithium-ion battery》 Example 1 First, 92.3 mg of LiNi as the positive electrode active material 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), and 8.4 mg of Li as lithium alloy particles. 3 A composite positive electrode active material particle precursor for lithium ion batteries containing Bi powder was obtained.

[0063] Specifically, in an inert environment, Li 3 The Bi powder was crushed. Then, nickel hydroxide Ni(OH) was used as the positive electrode active material. 2 was melted at 230℃, and crushed Li was added. 3Bi powder was added and dispersed, and then cooled and solidified to obtain a precursor block. The precursor block was then pulverized, and mixed with a manganese compound, a cobalt compound, and a lithium source, and sintered at 850°C for 15 hours in an oxygen atmosphere to obtain a composite positive electrode active material particle precursor for lithium ion batteries. Here, by superimposing an SEM (scanning electron microscope) image and EDS mapping of nickel (Ni) and bismuth (Bi), it was confirmed that the lithium alloy particles were dispersed in the positive electrode active material in the obtained composite positive electrode active material particle precursor, that is, the lithium alloy particles were included in the positive electrode active material.

[0064] The above-mentioned active material particle precursor, conductive additive, and binder were mixed in NMP to prepare a slurry, which was then applied to an Al foil as a positive electrode current collector layer and dried to obtain a positive electrode precursor layer.

[0065] The obtained positive electrode precursor layer was placed opposite to a negative electrode active material layer containing graphite as an active material via a separator, and the layers were dried in a vacuum, and a non-aqueous electrolyte was poured therein to obtain a lithium ion battery precursor.

[0066] <Examples 2 to 3> Lithium ion battery precursors of Examples 2 and 3 were obtained in the same manner as in Example 1, except that the content of the positive electrode active material and the type and content of the lithium alloy particles were changed as shown in Table 1.

[0067] <Reference examples 1~3> Lithium ion battery precursors of Reference Examples 1 to 3 were obtained in the same manner as in Examples 1 to 3, except that the same amounts of positive electrode active material particles and lithium alloy particles were used instead of the active material particle precursor.

[0068] "evaluation" <Battery capacity at first charge / discharge> Based on the mass of the positive electrode active material contained in the cell, the current value at 210 mA / g was defined as 1 C rate, the charge / discharge current value was 0.2 C, and the end current value was 0.03 C. CCCV charging and CCCV discharging were performed. The upper limit voltage during charging was 4.25 V, and the lower limit voltage during discharging was 2.50 V. The obtained CCCV discharge capacity was regarded as the capacity of the cell and was used as an evaluation index for the present disclosure.

[0069] <Cycle characteristics> After measuring the cell capacity, a cycle test (CC charge / CC discharge, upper and lower limit voltages of 3 to 4.25 V, 0.3 C rate) was performed to determine the number of cycles until the CC discharge capacity became 40% or less of the initial discharge capacity.

[0070] Table 1 shows the configurations and evaluation results of the examples and comparative examples.

[0071] [Table 1]

[0072] From Table 1, it can be seen that a lithium-ion battery using composite positive electrode active material particles for lithium-ion batteries in which lithium alloy particles or metal particles are dispersed in the positive electrode active material can suppress the decrease in capacity after initial charging while also suppressing the decrease in capacity when repeatedly charged and discharged. [Explanation of symbols]

[0073] 112 Composite Positive Electrode Active Material Particles for Lithium-Ion Batteries 1122 Cathode active material 1124 Lithium alloy particles 1126 Metal particles 10 positive electrode 11 Cathode active material layer 12 Positive electrode current collector 20 Separator 30 negative electrode 31 Negative electrode active material layer 32 Negative electrode current collector 100 Lithium-ion batteries

Claims

1. A composite positive electrode active material particle for a lithium ion battery, comprising: A positive electrode active material, and Lithium alloying potential is 0.5V (vs Li / Li ＋ ) or more, and / or metal particles produced by desorption of lithium from the lithium alloy particles. It contains The lithium alloy particles or the metal particles are dispersed in the positive electrode active material. Composite positive electrode active material particles for lithium-ion batteries.

2. The lithium alloy particles are ３ Bi, Li ３ 2. The composite positive electrode active material particle for a lithium ion battery according to claim 1, wherein the active material is selected from the group consisting of Sb, and LiSn.

3. 3. The composite positive electrode active material particle for a lithium ion battery according to claim 1, wherein the positive electrode active material is an NCM lithium oxide.

4. A positive electrode active material layer comprising the composite positive electrode active material particle for a lithium ion battery according to claim 1 or 2.

5. A lithium ion battery comprising the positive electrode active material layer according to claim 4.

6. A positive electrode active material and lithium dispersed in the positive electrode active material, the alloying potential of which is 0.5 V (vs Li / Li ＋ ) or more. preparing a positive electrode precursor layer containing at least the composite positive electrode active material particle precursor for a lithium ion battery; Obtaining a lithium ion battery precursor having the positive electrode precursor layer, a separator or solid electrolyte layer, and a negative electrode active material layer in this order and impregnated with an electrolytic solution; and performing an initial charge on the lithium ion battery precursor to convert the positive electrode precursor layer into a positive electrode active material layer; A method for producing a lithium ion battery, comprising:

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