JP5849543B2 - Electrode body for lithium ion secondary battery, method for producing electrode body for lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Description

The present invention relates to an electrode active material for a lithium ion secondary battery, an electrode body for a lithium ion secondary battery, and a lithium ion secondary battery.

Lithium ion secondary batteries are not only lightweight and have a high capacity, but also can be used in combination with an appropriate positive electrode active material, so they can be used in portable electronic devices, cameras, watches, power tools, hybrid vehicle batteries, etc. Widely applied.
As the positive electrode active material, LiMn ₂ O ₄ , LiMnO ₂ , LiCoO ₂ , LiCo _1-x
Ni _x O ₂ , LiNiO _{2 and the} like are known, and among them, LiCoO ₂ is preferable from the viewpoint of high charge / discharge voltage and charge / discharge capacity.

However, since the high activity of lithium and the organic electrolyte are used, there is a concern about the danger of ignition at the time of a short circuit, so ensuring safety in the design of a lithium battery is a major issue.
Lithium polymer batteries using a gel polymer electrolyte and lithium ion batteries using a ceramic electrolyte have been developed as attempts to remove the electrolyte (see, for example, Patent Document 1).
. In particular, when a ceramic electrolyte is used, the ions that move in the electrolyte due to the battery reaction can be only lithium ions, there are almost no side reactions, no flammable organic solution is contained, and there are further sealing members and liquid sealing structures. It can be simplified or unnecessary, and the lithium ion secondary battery can be made smaller and thinner.

In the production of a lithium ion secondary battery using a ceramic electrolyte, there is a method in which ceramic electrolyte powder is compacted together with an electrode active material.
However, in such a method, not only the interface between the ceramic electrolyte powder and the electrode active material powder or the interface between the ceramic electrolyte powders is insufficient, and the battery output cannot be sufficiently obtained, but the charge / discharge cycle Due to the volume change accompanying this, the interface contact becomes unstable and the cycle life is deteriorated.

In order to solve the above problems, it is conceivable to heat and sinter the green compact, but in general, the ceramic used for the ceramic electrolyte has a high melting point (for example, several hundreds of degrees Celsius). A high temperature is required for sintering, and an interaction occurs between the ceramic electrolyte and the electrode active material during the sintering, and the ceramic electrolyte and the electrode active material are altered, resulting in deterioration of ionic conductivity and electrode performance.

JP 2006-277797 A

An object of the present invention is to provide an electrode active material for a lithium ion secondary battery that can be suitably used for the production of a lithium ion secondary battery excellent in output and cycle life, and for the lithium ion secondary battery. It is providing the electrode body for lithium ion secondary batteries manufactured using an electrode active material, and a lithium ion secondary battery.

In order to solve at least one of the above problems, problems, and objects, an electrode body for a lithium ion secondary battery according to the present invention includes an electrode active material for a lithium ion secondary battery and a ceramic electrolyte. And a collector electrode provided on one side of the electrode mixture layer and in contact with a part of the electrode active material for the lithium ion secondary battery, and the electrode active for the lithium ion secondary battery The material has mother particles composed of LiCoO ₂ and a coating layer composed of Li ₂ TiO ₃ , and the ceramic electrolyte includes perovskite-type lithium lanthanum titanate and is used as a positive electrode. .
In the one electrode body for a lithium ion secondary battery, it is preferable that the thickness of the coating layer is 10 nm or more and 100 nm or less.
In the above electrode body for a lithium ion secondary battery, it is preferable that the electrode mixture layer is manufactured by sintering at a temperature of 1100 ° C. or lower.
One lithium ion secondary battery according to the present invention has the above-described one electrode body for a lithium ion secondary battery.
Such an object is achieved by the present invention described below.
The electrode active material for a lithium ion secondary battery of the present invention is characterized by having mother particles composed of LiCoO 2 and a coating layer composed of Li 2 TiO 3.
According to the electrode active material for a lithium ion secondary battery, since the LiCoO2 mother particles are coated with thermally stable Li2TiO3 (melting point: 1520 ° C. to 1564 ° C.), the LiCoO 2 melting point is 1100 ° C. The LiCoO2 mother particles are not altered even if the firing is performed. For this reason, when a lithium ion secondary battery using a ceramic electrolyte as an electrolyte is manufactured by firing at a high temperature, the LiCoO2 mother particles are not altered, and the lithium ion secondary battery is excellent in output and cycle life. An electrode active material for a lithium ion secondary battery that can be suitably used for production can be provided.

In the electrode active material for a lithium ion secondary battery, the coating layer has a thickness of 10
The thickness is preferably from 100 nm to 100 nm.
In this way, the coating layer composed of the insulator Li ₂ TiO ₃ can not only sufficiently suppress the deterioration of the LiCoO ₂ mother particles, but also the electrons and lithium ions generated on the surface of the LiCoO ₂ mother particles during battery operation. Does not hinder the transfer.

An electrode body for a lithium ion secondary battery according to the present invention includes an electrode active material layer for the lithium ion secondary battery and an electrode mixture layer including a ceramic electrolyte, and a collector electrode, and the collector electrode is the electrode. A part of the electrode active material for a lithium ion secondary battery is provided in contact with one side of the composite material layer.
The electrode body for a lithium ion secondary battery includes an electrode mixture layer including the electrode active material for the lithium ion secondary battery and a ceramic electrolyte. Thus, by forming the electrode mixture layer including both the electrode active material and the ceramic electrolyte, it is possible to quickly exchange lithium ions between the ceramic electrolyte and the electrode active material.

The distribution of the electrode active material and the ceramic electrolyte in such an electrode mixture layer is not particularly defined. For example, each of the electrode active material and the ceramic electrolyte is laminated in a single layer in the electrode mixture layer. The distribution form in which the electrode active material and the ceramic electrolyte are mixed as particles may be used.
In the electrode body for a lithium ion secondary battery, the collector electrode is provided on one side of the electrode mixture layer so that a part of the electrode active material is in contact with it. As a result, it is possible to quickly transfer electrons between the electrode active material and the collector electrode during battery operation.

The electrode body for a lithium ion secondary battery is characterized in that the electrode mixture layer is manufactured by sintering.
In the electrode mixture layer, LiC in the electrode active material for the lithium ion secondary battery
The oO ₂ mother particles come into contact with the ceramic electrolyte through a thermally stable Li ₂ TiO ₃ coating layer. As a result, when this electrode mixture layer is fired, the LiCoO ₂ mother particles and the ceramic electrolyte are not in direct contact with each other, and LiCoO ₂ is melted without altering both.
Firing at a temperature of 00 ° C. or lower is possible.

By firing at such a high temperature, the connection (sintering) between the active material particles, between the ceramic electrolyte particles, and between the active material particles and the ceramic electrolyte particles can proceed, so that the lithium ion secondary battery Active material particles, ceramic electrolyte particles, and the contact between the active material particles for lithium ion secondary batteries and the ceramic electrolyte particles can be sufficient, from the active material during battery operation to the collector electrode This facilitates smoothing of the electron conduction of the battery and lithium ion conduction from the active material to the ceramic electrolyte, so that the battery output of the lithium ion secondary battery using this electrode body can be made sufficiently excellent, and the cycle life can be improved. It can be made particularly excellent.

In the electrode body for a lithium ion secondary battery, the ceramic electrolyte is preferably composed of perovskite type lithium lanthanum titanate.
Thereby, the interaction between the ceramic electrolyte and Li ₂ TiO ₃ can be suppressed to a temperature of 1200 ° C. or higher, and the electrode mixture layer can be reliably sintered at a temperature of 1100 ° C. or lower. The battery output of the conventional lithium ion secondary battery can be made sufficiently excellent, and the cycle life can be made particularly excellent.
In addition, perovskite lithium lanthanum titanate has a high lithium ion conductivity (
1.5 × 10 ⁻³ S / cm), it becomes possible to quickly exchange lithium ions between the ceramic electrolyte and the electrode active material, and the lithium ion secondary battery using this electrode body The output can be improved.

The lithium ion secondary battery of the present invention is characterized in that the electrode body for a lithium ion secondary battery is used as a positive electrode.
Thereby, a lithium ion secondary battery with high battery voltage and excellent output and cycle life can be provided.

It is typical sectional drawing for demonstrating the structure of the electrode active material of this invention. It is typical sectional drawing for demonstrating one form of a structure of the electrode body of this invention. It is typical sectional drawing for demonstrating another form of the structure of the electrode body of this invention. It is typical sectional drawing for demonstrating one form of a structure of the lithium ion secondary battery of this invention. It is typical sectional drawing for demonstrating another form of the structure of the lithium ion secondary battery of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
<Electrode active material for lithium ion secondary battery>
First, the electrode active material for lithium ion secondary batteries of the present invention (hereinafter also simply referred to as “electrode active material”) will be described in detail.
According to this electrode active material for a lithium ion secondary battery, LiCoO ₂ mother particles are coated with thermally stable Li ₂ TiO ₃ (melting point: 1520 ° C. to 1564 ° C.).
Even when firing at a temperature up to 1100 ° C., which is the melting point of O _2, the LiCoO _{2 base} particles are not altered.

FIG. 1 is a schematic cross-sectional view for explaining the configuration of the electrode active material of the present invention.
The electrode active material 1 has a mother particle 11 made of LiCoO ₂ and a coating layer 12 made of Li ₂ TiO ₃ . When the electrode active material 1 has such a configuration, when the electrode active material 1 is sintered together with the ceramic electrolyte, it is possible to reliably prevent an undesirable interaction between them, and the ceramic. It is possible to reliably prevent ionic conductivity, electrode performance deterioration, and the like caused by alteration of the electrolyte and electrode active material. Therefore, the electrode active material of the present invention can be suitably used for the production of a lithium ion secondary battery excellent in output and cycle life.

<Mother particles>
The mother particles 11 constituting the electrode active material (positive electrode active material) 1 are composed of LiCoO ₂ .
LiCoO ₂ is an advantageous material as an electrode active material of a lithium ion secondary battery from the viewpoint of a high charge / discharge voltage and charge / discharge capacity among various known electrode active materials. In addition, since the unipolar potential is high (3.9 V with respect to the Li electrode), it is particularly suitable for use in the positive electrode.

Note that the mother particles 11 may be any particles that are mainly composed of LiCoO _2.
Components other than O ₂ (hereinafter referred to as “other components”) may be included at a predetermined ratio. In this case, the proportion of other components in the mother particle 11 is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. Thus, it is possible to sufficiently exhibit the characteristics LiCoO ₂ itself has.

<Coating layer>
The mother particle 11 described above is covered with a covering layer 12 made of Li ₂ TiO ₃ .
Li ₂ TiO ₃ constituting the coating layer 12 has a melting point of 1520 ° C. to 1564 ° C.
The thermal stability is high, and in particular, the stability in a high temperature environment such as a sintering process is high. Thereby, when the electrode active material 1 is sintered together with the ceramic electrolyte, the LiC constituting the mother particle 11 is formed.
between oO ₂ and the ceramic electrolyte, without causing undesirable interaction, it is not the LiCoO ₂ core particles be subjected to calcination at temperatures up to 1100 ° C. which is the melting point of LiCoO ₂ is deteriorated. As a result, it is possible to reliably prevent ionic conductivity, electrode performance degradation, and the like caused by alteration of the electrode active material 1.

The thickness of the coating layer 12 is preferably 10 nm or more and 100 nm or less. This
The coating layer made of Li ₂ TiO ₃ that is an insulator can not only sufficiently suppress the deterioration of the LiCoO ₂ mother particles, but also does not greatly hinder the transfer of electrons and lithium ions generated on the surface of the LiCoO ₂ mother particles during battery operation. On the other hand, when the thickness of the coating layer 12 is less than the lower limit, it is not possible to suppress the deterioration of the LiCoO ₂ mother particles. On the other hand, if the thickness of the coating layer 12 exceeds the upper limit, the exchange of electrons and lithium ions generated on the surface of the LiCoO ₂ mother particles during battery operation is greatly hindered, and an output current cannot be obtained.

The covering layer 12 may be formed by any method. For example, a liquid containing LiCoO ₂ particles to be the mother particles 11 and Li ₂ TiO ₃ fine particles that are constituent materials of the covering layer 12 ( A dispersion liquid), a method of collecting LiCoO ₂ particles and Li ₂ TiO ₃ particles in this liquid for a _second , a sol-gel method such as a gas phase film formation method, a complex polymerization method, an alkoxide method, an organometallic decomposition Law.

Note that the coating layer 12 may be any layer mainly composed of Li ₂ TiO ₃ , and Li ₂
A component other than TiO ₃ (hereinafter referred to as “other components”) may be included at a predetermined ratio. In this case, the proportion of other components in the coating layer 12 is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. Thereby, the effect of the present invention as described above can be made remarkable.
In order to change the thickness of the coating layer, for example, the time for immersing the mother particles in the dispersion, the deposition time in the vapor deposition method, or the concentration of the sol-gel solution to be immersed may be changed.

<Electrode body for lithium ion secondary battery>
The electrode body for a lithium ion secondary battery of the present invention (hereinafter also simply referred to as “electrode body”) is made of a material containing the electrode active material of the present invention as described above. By making an electrode body into the material containing the electrode active material of this invention, the said electrode body can be used suitably for manufacture of the lithium ion secondary battery excellent in an output and a cycle life.

FIG. 2 is a schematic cross-sectional view for explaining one embodiment of the configuration of the electrode body of the present invention.
FIG. 3 is a schematic cross-sectional view for explaining another embodiment of the configuration of the electrode body of the present invention.
The electrode body 19 includes an electrode mixture layer 23 including the electrode active material 21 and a ceramic electrolyte 22.
And a collecting electrode 25. The collector electrode 25 is characterized in that a part of the electrode active material 21 is brought into contact with one side of the electrode mixture layer 23.
Thus, by forming the electrode mixture layer including both the electrode active material and the ceramic electrolyte, it is possible to quickly exchange lithium ions between the ceramic electrolyte and the electrode active material.

The distribution of the electrode active material and the ceramic electrolyte in the electrode mixture layer is not particularly defined, but as illustrated in FIG. 2, the electrode active material 21 and the ceramic electrolyte 22 in the electrode mixture layer 23. Each may have a distributed form in which a single layer is formed, or as illustrated in FIG. 3, the electrode active material 21 and the ceramic electrolyte 22 are mixed as particles in the electrode mixture layer 24. A distribution form may be used.

Further, in the electrode body 19 or 20, a collector electrode is provided on one side of the electrode mixture layer so that a part of the electrode active material is in contact therewith. As a result, it is possible to quickly transfer electrons between the electrode active material and the collector electrode during battery operation.
The electrode mixture layer can be formed by, for example, a method described in JP2011-65982A.

As the ceramic electrolyte 22, various materials listed below can be used.
(1) Inorganic crystal, inorganic glass or partially crystallized glass having lithium ion conductivity (2) LiTi ₂ (PO ₄ ) ₃ , Li _1.3 M _0.3 Ti _1.7 (PO ₄ ) ₃ [However, NASICON type ceramic crystal such as M = Al, Sc] (3) Perovskite type lithium lanthanum titanate crystal such as Li _0.35 La _0.55 TiO ₃ (4) LiSr ₂ TiTaO ₆ , Li _3x La _{1 / 3-x} Perovskite-type ceramic crystals such as TaO ₃ (5) Thioricin crystals such as Li _4-x Si _1-x P _x S ₄ and Li _4-x Ge _1-x P _x S ₄ (6) Li ₁₄ Zn (GeO ₄ ) Rishikon crystals such as ₄ (7) Li doped _β-Al 2 _{O 3} crystal (8) partially crystallized glass containing the crystal _{(9) Li 2 S-SiS} 2 -Li O _{3 system,} Li 2 sulfide glass _(10), such as _S-P 2 _{S 5} -based _{Li 2 O-SiO 2 -B 2} O 3 _{system, Li 2 O-SiO 2 -ZrO} 2 based oxide glass (11) LIPON glass (see, for example, Japanese Patent Application Laid-Open No. 2004-179158)
(12) LiI crystal (13) Li ₃ PO ₄ crystal (14) Garnet-type ceramic crystal such as Li7La ₃ Zr ₂ O ₁₂

The electrode mixture layers 23 and 24 constituting the electrode body of the present invention may be made of a material containing the electrode active material 21 and the ceramic electrolyte 22, and may contain other components. Examples of such components (other components) include conductive materials and binder materials.
As the conductive substance, a material having high conductivity is preferably used. For example, carbon particles such as acetylene black and ketjen black and metals with high oxidation resistance (including alloys)
Is preferably used. As a metal with high oxidation resistance, after sintering, the conductivity is 1 × 10
A metal having a conductivity of ¹ S / cm or more can be given. Specific examples of such metals include
Examples thereof include simple noble metals such as Pd, Au, and Pt, and alloys containing two or more metals selected from the group consisting of Pd, Au, and Pt (for example, PtPd alloys).
Moreover, as a binder substance, the organic substance etc. which consist of a styrene-type thermoplastic elastomer, polyolefin, polyamide, a polyimide, etc. can be used, for example.

Since the electrode active material (positive electrode active material) of the present invention has low reactivity with the above-mentioned conductive materials and the like in addition to the ceramic electrolyte, it is possible to reliably prevent deterioration of ion conductivity and electrode performance. The lithium ion secondary battery finally obtained can be surely excellent in output and cycle life.
Examples of the constituent material of the collector electrode 25 include Cu, Ti, Fe, Co, Ni, Zn, and Al.
, Ge, In, Au, Pt, Ag and Pd, a single metal selected from the group consisting of, and an alloy containing two or more elements selected from the above group.

Moreover, the collector electrode 25 can be attached after the electrode mixture layers 23 and 24 are manufactured by firing, or can be fired together with the electrode mixture layers 23 and 24 as described later.
Examples of the method for attaching the collector electrode 25 include pressure bonding, sputter deposition, and vacuum deposition.
The electrode mixture layers 23 and 24 can be manufactured by sintering.

In the electrode mixture layer, LiC in the electrode active material for the lithium ion secondary battery
The oO ₂ mother particles come into contact with the ceramic electrolyte through a thermally stable Li ₂ TiO ₃ coating layer. As a result, when the electrode mixture layer is fired, the LiCoO ₂ mother particles and the ceramic electrolyte are not in direct contact with each other, and can be fired at a temperature below the melting point of LiCoO ₂ without altering both. Become.

The firing temperature of the electrode mixture layer can be 1100 ° C. or lower, which is the melting point of LiCoO ₂ . Unfavorable interaction between the ceramic electrolyte and the Li ₂ TiO ₃ coating is 1100
When it occurs at a temperature below 0 ° C., it may be fired at a temperature below that temperature at which the reaction occurs.
Further, when the electrode mixture layer contains the conductive material or binder material, and an undesirable interaction occurs between the conductive material or binder material and the ceramic electrolyte or the Li ₂ TiO ₃ coating layer, You may bake below the temperature which a reaction produces.

By firing at such a high temperature, the connection (sintering) between the active material particles, between the ceramic electrolyte particles, and between the active material particles and the ceramic electrolyte particles can proceed, so that the lithium ion secondary battery Active material particles, ceramic electrolyte particles, and the contact between the active material particles for lithium ion secondary batteries and the ceramic electrolyte particles can be sufficient, from the active material during battery operation to the collector electrode This facilitates smoothing of the electron conduction of the battery and lithium ion conduction from the active material to the ceramic electrolyte, so that the battery output of the lithium ion secondary battery using this electrode body can be made sufficiently excellent, and the cycle life can be improved. It can be made particularly excellent.

When the ceramic electrolyte 22 is composed of perovskite-type lithium lanthanum titanate, the interaction between the ceramic electrolyte 22 and the Li ₂ TiO ₃ coating layer of the electrode active material 21 can be suppressed to a temperature of 1200 ° C. or higher. Therefore, sintering of the electrode mixture layer at a temperature of 1100 ° C. or lower is ensured. For this reason, the battery output of the lithium ion secondary battery using this electrode body can be made sufficiently excellent, and the cycle life can be made particularly excellent.
In addition, perovskite lithium lanthanum titanate has a high lithium ion conductivity (
1.5 × 10 ⁻³ S / cm), it becomes possible to quickly exchange lithium ions between the ceramic electrolyte and the electrode active material, and the lithium ion secondary battery using this electrode body The output can be improved.

《Lithium ion secondary battery》
Next, the lithium ion secondary battery of the present invention will be described in detail.
The lithium ion secondary battery of the present invention is characterized in that the electrode body of the present invention as described above is used for a positive electrode. Since the electrode body of the present invention contains LiCoO ₂ having a high monopolar potential, the use of the electrode body as a positive electrode provides a lithium ion secondary battery with high battery voltage and excellent output and cycle life. Can do.

FIG. 4 is a schematic cross-sectional view for explaining one embodiment of the configuration of the lithium ion secondary battery of the present invention.
This lithium ion secondary battery 50 uses the electrode body 19 shown in FIG. 2 as the electrode body for the positive electrode 40, and the negative electrode active material layer on the electrode mixture layer 23, that is, on the side opposite to the collector electrode 25. 31 and the collector electrode 26 are laminated in this order to form a negative electrode 41.

As the negative electrode active material layer 31, a foil of a metal active material such as lithium metal, a Li—In alloy, or a Li—Al alloy can be used, graphite, carbon powder, or Li ₄ T.
It is also possible to use an active material powder such as i ₅ O ₁₂ powder obtained by molding binder particles and / or conductive particles. Here, for example, particles made of styrene thermoplastic elastomer, polyolefin, polyamide, polyimide or the like are used as the binder particles, and carbon particles such as acetylene black or ketjen black are used as the conductive particles.

The collector electrode 26 is made of the same material as the collector electrode 25 of the electrode body (19, 20).
Then, the electrode body 19, the negative electrode active material layer 31, and the collector electrode 26 are laminated, and the whole is pressure-molded and integrated, whereby the lithium ion secondary battery 50 is obtained. A positive electrode wiring layer (not shown) is connected to the collector electrode 25 on the positive electrode 40 side, and a negative electrode wiring layer (not shown) is connected to the collector electrode 26 of the negative electrode 41.

Further, like the lithium ion secondary battery 51 of another embodiment shown in FIG. 5, the electrode body 20 shown in FIG. 3 can be used for the positive electrode 40 as the electrode body.
Further, like the lithium ion secondary battery 51, the electrolyte layer 30 can be provided between the positive electrode 40 and the negative electrode 41. By doing so, it is possible to reliably prevent an electrical short circuit between the positive electrode 40 and the negative electrode 41.

As the electrolyte layer 30, a polymer electrolyte such as a ceramic electrolyte composed of the same material as the ceramic electrolyte 22 or a material capable of constituting the ceramic electrolyte 22, polyethylene oxide added with lithium bistrifluoromethanesulfonylimide (LiTFSI), and the like. Or a polypropylene porous membrane (such as Celgard 2400) impregnated with an organic electrolyte such as a saturated solution of lithium hexafluorophosphate or lithium chlorate in ethylene carbonate or diethylene glycol It can be used suitably.

The shape of the lithium ion secondary battery of the present invention is not particularly limited, and may be any shape such as a coin shape, a button shape, a sheet shape, a stacked shape, a cylindrical shape, a flat shape, a rectangular shape, and the like.
For example, in the above-described embodiment, the lithium ion secondary battery having a structure in which each of the positive electrode and the negative electrode has one layer has been representatively described. However, the lithium ion secondary battery includes a plurality of positive electrodes, ceramic electrolyte layers, and negative electrodes. It may have a layer.
In the above-described embodiment, the configuration in which the positive electrode and the negative electrode have a flat plate shape is representatively described. However, the lithium ion secondary battery has, for example, a configuration in which a laminate including a positive electrode and a negative electrode is wound. It may be a thing.

DESCRIPTION OF SYMBOLS 1 ... Electrode active material 11 ... Mother particle 12 ... Coating layer 19, 20 ... Electrode body 21 ... Electrode active material 22 ... Ceramic electrolyte 23, 24 ... Electrode compound layer 25, 26 ... Collector electrode 30 ... Electrolyte layer 31 ... Negative electrode active Material layer 40 ... Positive electrode 41 ... Negative electrode 50, 51 ... Lithium ion secondary battery

Claims (4)

An electrode mixture layer comprising an electrode active material for a lithium ion secondary battery and a ceramic electrolyte;
A collector electrode provided on one side of the electrode mixture layer and in contact with a part of the electrode active material for the lithium ion secondary battery,
The electrode active material for a lithium ion secondary battery has mother particles composed of LiCoO ₂ and a coating layer composed of Li ₂ TiO ₃ ,
The ceramic electrolyte comprises perovskite lithium lanthanum titanate;
An electrode body for a lithium ion secondary battery, which is used as a positive electrode.   The electrode body for a lithium ion secondary battery according to claim 1, wherein the coating layer has a thickness of 10 nm to 100 nm. A method for producing an electrode body for a lithium ion secondary battery used as a positive electrode,
An electrode mixture layer comprising an electrode active material for a lithium ion secondary battery and a ceramic electrolyte;
A collector electrode provided on one side of the electrode mixture layer and in contact with a part of the electrode active material for the lithium ion secondary battery,
The electrode active material for a lithium ion secondary battery has mother particles composed of LiCoO ₂ and a coating layer composed of Li ₂ TiO ₃ ,
The ceramic electrolyte comprises perovskite lithium lanthanum titanate;
The method for producing an electrode body for a lithium ion secondary battery, wherein the electrode mixture layer is produced by sintering at a temperature of 1100 ° C. or lower. A lithium ion secondary battery comprising the electrode body for a lithium ion secondary battery according to claim 1 .

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