JP6926528B2 - Selection method of coating material, positive electrode active material for lithium ion secondary battery, lithium ion secondary battery - Google Patents

Description

The present invention relates to a method for selecting a coating material, a positive electrode active material for a lithium ion secondary battery, and a lithium ion secondary battery.

Lithium-ion secondary batteries have high voltage and high capacity, so they are widely used as secondary batteries for notebook computers and mobile phones that require high output and miniaturization, and as in-vehicle batteries for hybrid vehicles and electric vehicles. ing.

A lithium ion secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, a separator and the like. _{LiCoO 2} and LiNiO ₂ are used as the positive electrode active material used for the positive electrode. Among them, LiNiO ₂ is a promising material because of its high energy density.

By the way, the positive electrode active material used in a lithium ion secondary battery is generally unstable, reacts with an electrolytic solution and moisture in the atmosphere, causes surface deterioration, and the battery characteristics gradually deteriorate. There was a challenge. In particular, LiNiO ₂ has a _{greater surface deterioration and property deterioration than LiCoO 2} , and there is a strong demand for overcoming it.

Therefore, a method has been proposed in which the positive electrode active material is coated with another material to protect the positive electrode active material from electrolytic solution and atmospheric exposure, thereby suppressing surface deterioration while maintaining the battery characteristics.

For example, Patent Document 1 describes positive electrode active material particles containing nickel atoms in a proportion of 80 atomic% or more with respect to all metal atoms other than lithium atoms in the positive electrode active material particles, and the positive electrode active material particles are covered with diamond-like particles. The coating layer contains a coating layer containing carbon, the layer thickness of the coating layer is 5 to 20 nm, and the SP ² / SP ³ ratio of the coating layer is 55/45 to 60/40. Coated particles for lithium ion secondary batteries are disclosed.

Japanese Unexamined Patent Publication No. 2016-72177

However, a specific selection method for the coating material for the positive electrode active material of the lithium ion secondary battery has not been known. Therefore, in order to find a coating material capable of suppressing surface deterioration while maintaining the battery characteristics, it is necessary to test various candidate coating materials, which poses a problem in terms of efficiency.

In addition, various adjustments are required to reliably coat the positive electrode active material of the lithium ion secondary battery, and it is not easy to interpret the obtained results. That is, it is difficult to prepare a sample for all of the various candidate coating materials, and even if it can be produced, it is difficult to appropriately evaluate the coating material. Therefore, it was very difficult and costly to find an effective coating material on a trial basis.

Therefore, from the viewpoint of efficiency, suppressing technical difficulties, and cost reduction, it is desirable to select a promising coating material in advance and then perform the test, but surface alteration is performed while maintaining the battery characteristics. A method for selecting a coating material that can suppress the above has not yet been developed.

In view of the above-mentioned problems of the prior art, one aspect of the present invention is to provide a method for selecting a coating material capable of selecting a coating material capable of suppressing surface deterioration while maintaining battery characteristics.

According to one aspect of the present invention in order to solve the above problems.
A method for selecting a coating material for coating the surface of a positive electrode active material for a lithium ion secondary battery.
For candidate materials are candidates of the coating material, and the activation energy calculating step of calculating the activation energy E _A lithium diffusion in the interior of the candidate material using a first-principles calculation,
If it meets the activation energy E _B of lithium diffusion in the positive electrode active material for lithium ion secondary batteries, the lithium diffusion activation energy E _A and the E _{A <E B} in the interior of the candidate material, the candidate material A selection step for selecting a coating material as a coating material, and a method for selecting a coating material having the above are provided.

According to one aspect of the present invention, it is possible to provide a method for selecting a coating material capable of selecting a coating material capable of suppressing surface deterioration while maintaining battery characteristics.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments and does not deviate from the scope of the present invention. Can be modified and substituted in various ways.
[Selection method of coating material]
In the present embodiment, first, a configuration example of a method for selecting a coating material will be described.

The coating material selection method of the present embodiment may include the following steps with respect to the coating material selection method for coating the surface of the positive electrode active material for a lithium ion secondary battery.

For candidate materials are candidates of the coating material, the activation energy calculating step of calculating the activation energy E _A lithium diffusion in the interior of the candidate materials using the first-principles calculation.

If it meets the activation energy E _B of lithium diffusion in the positive electrode active material for a lithium ion secondary battery, and the activation energy E _A lithium diffusion in the interior of the candidate materials to E _{A <E B,} the candidate material-coated material Selection process to select as.

The inventors of the present invention have diligently studied a method for selecting a coating material that can suppress surface deterioration while maintaining battery characteristics. Then, by paying attention to the diffusibility of lithium, it was found that the optimum coating material can be selected.

According to the study by the inventors of the present invention, this is because a substance having excellent lithium diffusivity is used as a coating material and the positive electrode active material is coated, so that the transfer of lithium is hindered by the coating material. This is because lithium can be moved even in a low voltage region. Therefore, the water resistance can be improved while maintaining the positive electrode resistance and the battery capacity (for example, the discharge capacity), that is, both the battery characteristics and the water resistance can be compatible, and the surface deterioration can be performed while maintaining the battery characteristics. Can be suppressed.

The positive electrode active material for a lithium ion secondary battery (hereinafter, also simply referred to as “positive electrode active material”) to be coated with the selected coating material is not particularly limited, and various positive electrode active materials can be used. However, the positive electrode active material containing nickel easily reacts with the electrolytic solution and the moisture in the atmosphere, and a coating material capable of suppressing surface deterioration while maintaining the battery characteristics has been particularly required. Therefore, the positive electrode active material to be coated with the coating material to be selected is preferably a positive electrode active material containing nickel, and specifically, for example, the positive electrode active material is preferably represented by _{LiMO 2.} As described above, M in the formula preferably contains nickel. The nickel content of M in the formula is not particularly limited, but the higher the nickel content, the easier it is to react with the electrolytic solution, etc. Therefore, M in the formula may contain nickel in a substance amount ratio of 30% or more. It is preferable, and it is more preferable to contain 60% or more. Further, since M in the formula may be composed of nickel only, it is preferable that nickel is contained in an amount ratio of 100% or less. When M in the formula contains a component other than nickel, examples of the component other than nickel include Co, Al, Mn and the like.

Hereinafter, each step of the method for selecting the coating material of the present embodiment will be described.

The activation energy calculation step, the candidate materials are candidates of the coating material, it is possible to calculate the activation energy E _A lithium diffusion inside the candidate material using a first-principles calculation.

The method of calculating the activation energy E _A are not particularly limited, it can be calculated by any method. For example, in a candidate material that is a candidate for a coating material, the energy of each point is calculated while moving a lithium atom along the reaction path, the reaction path with the lowest energy is searched for, and the energy difference in the reaction path is activated. it can be E _a.

Candidate materials that are candidates for the coating material to be used in this step are not particularly limited, and various materials to be narrowed down can be used as candidate materials, and various inorganic materials, organic materials, and the like can be mentioned. However, the candidate material for the coating material is preferably a stable material that is less likely to react with the electrolytic solution or moisture in the atmosphere than the positive electrode active material. This is because by coating the positive electrode active material with the coating material, it is possible to regulate the contact between the positive electrode active material and water, etc., as compared with the case where the positive electrode active material exists alone, so that the stability of the positive electrode active material is improved. be able to. However, as described above, it is preferable to use a coating material that is less likely to react with moisture or the like than the positive electrode active material because the stability of the positive electrode active material after coating can be particularly enhanced.

Next, in the selection step, the activation energy E _B of lithium diffusion in the positive electrode active material calculated in advance, when the E _A satisfies E _{A <E B,} candidate materials of the coating material was subjected to calculation Can be selected as the coating material.

There is no particular limitation on the method of calculating the activation energy E _B of lithium diffusion in the positive electrode active material, it can be calculated by any method. For example, as in the case of the activation energy E _A, the positive electrode active material, the energy of each point was calculated while moving along a lithium atom in the reaction path, looking for the lowest energy reaction path, within the reaction path the energy difference can be an activation energy E _B.

In the case of E _A ≧ E _B, the candidate material is determined not suitable as a coating material, it is possible to terminate the selection process.

The method for selecting the coating material of the present embodiment may have an arbitrary step other than the above-mentioned activation energy calculation step and selection step. In the method of selecting the coating material of the present embodiment, for example, when there are a plurality of candidate materials that are candidates for the coating material, the candidate materials to be used for the calculation are changed, and the above-mentioned activation energy calculation step and the selection step are repeatedly carried out. It can also have a process. By repeating the process, it is possible to screen a material suitable for the coating material from a plurality of coating materials.

According to the coating material selection method of the present embodiment described above, a coating material having better lithium diffusivity than the positive electrode active material can be easily selected by first-principles calculation. Therefore, it is possible to select a coating material that can suppress surface deterioration while maintaining the battery characteristics.
[Cathode active material for lithium-ion secondary batteries]
Next, a configuration example of the positive electrode active material for the lithium ion secondary battery of the present embodiment will be described.

The positive electrode active material for a lithium ion secondary battery of the present embodiment can include a coating material selected by the coating material selection method described above on the surface.

The state of the coating material that the positive electrode active material of the present embodiment has on its surface is not particularly limited, and can exist in any state.

For example, the coating material may be arranged in a layered or film form so as to cover the surface of the particles of the positive electrode active material. In this case, for example, the coating material may be arranged so as to cover a part or all of the surface of the particles of the positive electrode active material, or, for example, a part of the coating material may be arranged on the surface of the particles of the positive electrode active material. It may exist so as to dissolve in solid solution.

The method of arranging the coating material on the surface of the particles of the positive electrode active material of the present embodiment is not particularly limited, and can be arbitrarily selected depending on, for example, the material of the positive electrode active material, the type of the coating material, and the like. ..

For example, when the coating material is a water-soluble material, the coating material can be arranged on the surface of the positive electrode active material by mixing the positive electrode active material, the coating material, and water and drying them. Further, the coating material can be arranged on the surface of the positive electrode active material by spraying or dropping and mixing an aqueous solution containing the coating material on the positive electrode active material and then drying the mixture.

The positive electrode active material is a composite compound containing lithium, but a trace amount of excess lithium is usually present on the surface of the particles. Therefore, when left in the atmosphere, the surplus lithium reacts with moisture and the like to generate lithium carbonate and lithium hydroxide on the surface of the particles, and in a positive electrode active material or a lithium ion secondary battery using the positive electrode active material. Performance degradation is seen.

However, when the positive electrode active material and water are mixed to dispose the coating material on the surface of the positive electrode active material, is the excess lithium on the particle surface dissolved in water and removed? Since it reacts with the coating material, it hardly produces lithium carbonate or lithium hydroxide on the surface of the positive electrode active material. Therefore, the above operation does not cause a decrease in the performance of the positive electrode active material or the lithium ion secondary battery using the positive electrode active material.

In any of the above methods, the conditions for drying are not particularly limited, but for example, the drying temperature is preferably 450 ° C. or lower. This is because by setting the temperature to 450 ° C. or lower, it is possible to more reliably prevent the lithium component from being liberated from the positive electrode active material. The drying temperature is more preferably 100 ° C. or higher and 300 ° C. or lower from the viewpoint of sufficiently drying and particularly surely preventing the lithium component from being liberated from the positive electrode active material.

The drying time is not particularly limited, but it is preferably 1 hour or more and 24 hours or less in order to sufficiently dry and prevent a decrease in productivity.

The atmosphere at the time of drying is also not particularly limited, but a decarboxylation atmosphere is preferable in order to prevent the water and carbonic acid in the atmosphere from reacting with the positive electrode active material. For example, an inert gas or a vacuum atmosphere is preferable. Further, the pressure of the atmosphere at the time of drying is preferably 1 atm or less. This is because the water content of the positive electrode active material after drying can be sufficiently lowered by setting the pressure of the atmosphere to 1 atm or less.

The method of arranging the coating material on the surface of the particles of the positive electrode active material is not limited to the above-mentioned method as described above. For example, the coating material can be arranged on the surface of the positive electrode active material by mixing the positive electrode active material and the coating material in a solid phase and then performing a heat treatment.

The conditions for performing the heat treatment are not particularly limited, and the heat treatment temperature can be selected according to the positive electrode active material, the material of the coating material, and the like. Further, the atmosphere at the time of heat treatment is preferably a decarboxylation atmosphere in order to prevent the moisture and carbonic acid in the atmosphere from reacting with the positive electrode active material. For example, an inert gas or a vacuum atmosphere is preferable.

The coating material contained in the positive electrode active material of the present embodiment is selected by the method for selecting a coating material described above, and the type thereof is not particularly limited. For example, according to the study by the inventors of the present invention, B or Li ₂ WO ₄ can be preferably used as a coating material with _{respect to the positive electrode active material LiNiO 2.}

According to the positive electrode active material of the present embodiment described above, the coating material selected by the coating material selection method described above is contained in the surface thereof, specifically, the surface of the particles. Therefore, it is possible to obtain a positive electrode active material having excellent water resistance while maintaining the battery characteristics as compared with the case where the coating material is not contained.
[Lithium-ion secondary battery]
Next, a configuration example of the lithium ion secondary battery of the present embodiment will be described.

The lithium ion secondary battery of the present embodiment (hereinafter, also simply referred to as “lithium ion battery”) can have a configuration in which the above-mentioned positive electrode active material for a lithium ion secondary battery is used as a positive electrode material.

The lithium ion battery of the present embodiment can be a lithium ion battery using the above-mentioned positive electrode active material. More specifically, the lithium ion battery of the present embodiment can have a positive electrode using the above-mentioned positive electrode active material. The lithium ion battery can have substantially the same structure as a general lithium ion battery except that the above-mentioned positive electrode active material is used as the positive electrode material, and thus will be briefly described.

The lithium ion battery of the present embodiment has a structure including a case and a positive electrode, a negative electrode, a non-aqueous electrolyte solution, and a separator housed in the case.

Specifically, the lithium ion battery of the present embodiment can have a structure in which an electrode body impregnated with a non-aqueous electrolyte solution is sealed in a battery case. The electrode body referred to here has a structure in which a positive electrode and a negative electrode are laminated via a separator, and can be impregnated with a non-aqueous electrolyte solution as described above. Hereinafter, each member constituting the lithium ion battery will be described.

The positive electrode is a sheet-shaped member. For example, a positive electrode mixture paste made by mixing a positive electrode active material, a conductive material and a binder is applied to the surface of a current collector made of aluminum foil, and dried. Can be formed.

The negative electrode is a sheet-like member formed by applying, for example, a negative electrode mixture paste containing a negative electrode active material to the surface of a metal leaf current collector such as copper and drying it.

As the separator, for example, a thin film such as polyethylene or polypropylene, which has a large number of fine pores, can be used. It should be noted that there is no particular limitation as long as it has a function of a separator.

The non-aqueous electrolyte solution is obtained by dissolving a lithium salt as a supporting salt in an organic solvent. As the organic solvent, ethylene carbonate, propylene carbonate and the like can be used. As the electrolyte salt, LiPF ₆ , LiBF ₄ , LiClO _4, or the like can be used.

The lithium ion battery of the present embodiment uses the above-mentioned positive electrode active material as the positive electrode material. Therefore, the positive electrode active material has a coating material arranged on the surface of the particles, has excellent water resistance, and can exhibit stable battery characteristics.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples.
[Example 1]
(Selection of coating material)
The following steps were carried out to select the coating material.

Note that, by a plane wave basis first principle calculation software VASP (Vienna Ab initio Simulation Package) PAW method using (Projector Augmented Wave method), and _{E A} in the following activation energy calculation step, the positive electrode active for lithium ion batteries It was calculated and the activation energy _{E B} of lithium diffusion in LiNiO ₂ is a substance.

First-principles calculations were performed using a generalized gradient approximation of PBE (Perdew-Burke-Ernzehof) in the category of Density Functional Theory (DFT). The cutoff energy of the plane wave base was set to 500 eV, and the NEB method (Nudged Elastic Band method) was used for the calculation of the activation energy. That is, the energy of each point was calculated while moving the lithium atom along the reaction path, the reaction path having the lowest energy was searched for, and the energy difference in the reaction path was used as the activation energy.

_{In this example, LiMeO 2} was mentioned as a candidate material for the coating material, and the following steps were carried out while changing the type of metal of Me.

For candidate materials are candidates of the coating material, the activation energy calculating step of calculating the activation energy E _A lithium diffusion inside the candidate material using a first-principles calculation.

And the activation energy E _B of lithium diffusion in LiNiO ₂ is a cathode active material for a lithium ion secondary battery that has been calculated in advance, the activation of the lithium diffusion inside candidate materials calculated in energy calculation step activation energy E _A Doo is when satisfy E _{a <E B,} selecting step of selecting the candidate materials as a coating material.

A repeating step in which the above activation energy calculation step and the selection step are repeated by changing the candidate material that is a candidate for the coating material.

As a result, when Me is W, that is, when the candidate material is a candidate of the coating material is _Li 2 WO _4, since it was confirmed that the E A _{<E B,} in the selection step, _Li 2 WO ₄ was selected as the coating material.
(Positive electrode active material)
Therefore, a positive electrode active material was produced in which LiNiO ₂ which is a positive electrode active material was used as a base material and Li ₂ WO ₄ which was a selected coating material was arranged on the surface of the base material.

_{Specifically, first, the powder of LiNiO 2} which is the base material and _{the powder of Li 2} WO ₄ which is the selected coating material were mixed. At this time, the amount of W (tungsten) in the powder _{of the selected coating material Li 2} WO ₄ is 3 mol% with respect to Ni contained in the powder of _{LiNiO 2} which is the base material of the positive electrode active material. Weighed and mixed.

Then, water was added to the above mixture so as to be 10% by mass with respect to _{LiNiO 2 as a base material, and further mixed.}

Then, in a vacuum atmosphere, the temperature is raised to 100 ° C. for 12 hours, and the temperature is further raised to 190 ° C. and dried for 10 hours. Obtained active material.
(Lithium-ion secondary battery)
A lithium ion secondary battery was produced using a positive electrode active material containing a coating material on the surface obtained by the above procedure, and evaluated.

To 70% by mass of the positive electrode active material powder prepared by the above procedure, 20% by mass of acetylene black as a conductive material and 10% by mass of PTFE (polytetrafluoroethylene) as a binder were added and mixed, and 150 mg from this was added. Was taken out to prepare pellets and used as a positive electrode.

Lithium metal was used as the negative electrode.

As the non-aqueous electrolyte solution, an equal amount mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) having _{1M LiClO 4 as a supporting salt (manufactured by Tomiyama Pure Chemical Industries, Ltd.) was used.}

A polyethylene porous membrane was used as the separator.

Then, in a glove box having an Ar atmosphere with a dew point controlled at −80 ° C., a 2032 type coin-type battery, which is a lithium ion secondary battery, was produced using each of the above members.

Further, for comparison, a lithium ion secondary battery was similarly prepared and evaluated using _{the positive electrode active material, that is, LiNiO 2,} which was prepared in the same manner except that the coating material was not arranged on the surface.

When the initial discharge capacity and positive electrode resistance of the obtained lithium ion secondary battery were evaluated, when LiNiO ₂ having a coating material arranged was used as the positive electrode material, _{LiNiO 2 having no coating material was used as the positive electrode material.} It was confirmed that the initial discharge capacity and positive electrode resistance were the same as in the case of the above. That is, even when the coating material is arranged on the particle surface, the same energy density and positive electrode resistance as in the case where the coating material is not arranged can be maintained, and it can be said that the battery characteristics can be maintained.

The initial discharge capacity is the cutoff voltage with the ^{current density for the positive electrode set to 0.1 mA / cm 2} after the open circuit voltage OCV (Open Circuit Voltage) stabilizes after leaving it for about 24 hours after manufacturing the coin-type battery. It is a value measured by the capacity when the battery is charged to 4.3 V, paused for 1 hour, and then discharged to a cutoff voltage of 3.0 V.

Further, when the coin-type battery is charged at a charging potential of 4.1 V and measured by the AC impedance method using a frequency response analyzer and a potentiogalvanostat (manufactured by Solartron, 1255B), a Nyquist plot can be obtained. The Nyquist plot is expressed as the sum of the solution resistance, the negative electrode resistance and its capacitance, and the characteristic curve showing the positive electrode resistance and its capacitance. Therefore, the positive electrode resistance was calculated by performing a fitting calculation using an equivalent circuit based on the obtained Nyquist plot.

Further, when the cycle characteristics of the obtained lithium ion secondary battery were evaluated, it was confirmed that the obtained lithium ion secondary battery showed stable performance and was excellent in cycle characteristics, that is, excellent in water resistance. Therefore, it was confirmed that the surface deterioration could be suppressed by arranging the coating material on the surface of the positive electrode active material.

Furthermore, the LiNiO ₂ obtained by placing the coating material to the surface, for a LiNiO ₂ have not placed the coated material was allowed to stand for one day in each atmosphere, using the materials in the positive electrode active material, as in the case described above A 2032 type coin-type battery, which is a lithium-ion secondary battery, was produced and the capacity retention rate was evaluated.

In the evaluation of the capacity retention rate, the current density was set to 0.3 mA / cm ² in a constant temperature bath maintained at 25 ° C., the cutoff voltage was charged to 4.9 V, and after a one-hour rest, the cutoff voltage was 3. After conditioning to repeat the cycle of discharging to 5V for 5 cycles, the current density is set to 2.0mA / cm ² and the cutoff voltage is charged to 4.9V in a constant temperature bath maintained at 60 ° C., and the device is paused for 1 hour. After that, the cycle of discharging to a cutoff voltage of 3.5 V was repeated for 200 cycles, and the discharge capacity of each cycle was measured. Then, the capacity retention rate, which is the ratio obtained by dividing the discharge capacity obtained in the first cycle after conditioning by the discharge capacity obtained in the cycle 200 cycles after conditioning, was calculated. As a result, it was confirmed that the capacity retention rate of the lithium secondary battery using _{LiNiO 2} having the coating material arranged on the surface as the positive electrode material was higher.
[Example 2]
(Selection of coating material)
ZnO was mentioned as a candidate material as a candidate for the coating material, and the activation energy calculation step and the selection step were carried out in the same manner as in Example 1.

_However, because they did not satisfy _E A <E _B, ZnO was not selected as a coating material.

In order to evaluate whether the above selection is appropriate, a positive electrode active material using ZnO as a coating material was produced and evaluated.
(Positive electrode active material)
_{A positive electrode active material was produced using LiNiO 2} , which is a positive electrode active material, as a base material, and ZnO, which is a selected coating material, was arranged on the surface thereof.

Specifically, first, _{the powder of LiNiO 2} which is the base material and the powder of ZnO which is the selected coating material were mixed. At this time, the amount of Zn (zinc) in the powder of ZnO, which is the selected coating material, was 3 mol% with respect to Ni contained in the powder of _{LiNiO 2} , which is the base material, and the mixture was weighed and mixed.

Then, water was added to the above mixture so as to be 10% by mass with respect to _{LiNiO 2 as a base material, and further mixed.}

Then, in a vacuum atmosphere, the temperature is raised to 100 ° C. for 12 hours, and the temperature is further raised to 190 ° C. and dried for 10 hours to obtain the positive electrode active material in which the coating material is arranged on the surface of the base material of the positive electrode active material. Obtained.
(Lithium-ion secondary battery)
A lithium ion secondary battery was produced in the same manner as in Example 1 except that the positive electrode active material in which ZnO, which is a coating material, was arranged on the surface of the particles of the base material of the positive electrode active material was used.

As a result, the positive electrode resistance is significantly higher than that of the lithium ion secondary battery in which the _{LiNiO 2} prepared in Example 1 in which the coating material is not arranged is used as the positive electrode material, and the capacity of _{LiNO 2 is utilized.} Was not possible. That is, it was confirmed that the battery characteristics were significantly lower than those in the case where _{LiNO 2} on which the coating material was not arranged was used as the positive electrode material.

Claims (4)

A method for selecting a coating material for coating the surface of a positive electrode active material for a lithium ion secondary battery.
For candidate materials are candidates of the coating material, and the activation energy calculating step of calculating the activation energy E _A lithium diffusion in the interior of the candidate material using a first-principles calculation,
If it meets the activation energy E _B of lithium diffusion in the positive electrode active material for lithium ion secondary batteries, the lithium diffusion activation energy E _A and the E _{A <E B} in the interior of the candidate material, the candidate material A selection step for selecting a coating material as a coating material, and a method for selecting a coating material. The method for selecting a coating material according to claim 1, wherein the positive electrode active material for a lithium ion secondary battery _{is represented by LiMO 2 (M contains nickel).} Look-containing coating material which is selected by the selection method of the coating material according to claim 1 or 2 on the surface, the positive electrode active material for a lithium ion secondary battery as the coating material B. A lithium ion secondary battery using the positive electrode active material for a lithium ion secondary battery according to claim 3 as a positive electrode material.