JP2006073482A - Positive electrode material for nonaqueous electrolyte lithium ion secondary battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode material suitably used in a nonaqueous electrolyte lithium ion secondary battery capable of supplying power stably for a long period and with high output. <P>SOLUTION: In the positive electrode material for nonaqueous electrolyte lithium ion secondary battery, the surface of a particle made of lithium nickel cobalt manganese oxide is deposited with a lithium compound. Its manufacturing method is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positive electrode material for a non-aqueous electrolyte lithium ion secondary battery. Specifically, the present invention relates to an improvement in a positive electrode material for a non-aqueous electrolyte lithium ion secondary battery using lithium nickel cobalt manganese oxide as a positive electrode active material.

  In recent years, in order to cope with air pollution and global warming, reduction of the amount of carbon dioxide has been strongly desired. In the automobile industry, the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV) is expected to reduce carbon dioxide emissions, and the development of secondary batteries for motor drive that holds the key to commercialization of these is actively done. Has been done.

  As a secondary battery for driving a motor, a lithium ion secondary battery having the highest theoretical energy among all the batteries is attracting attention, and is currently being developed rapidly. Generally, a lithium ion secondary battery includes a positive electrode in which a positive electrode active material or the like is applied to both surfaces of a positive electrode current collector using a binder, and a negative electrode in which a negative electrode active material or the like is applied to both surfaces of a negative electrode current collector using a binder. However, it has the structure connected through an electrolyte layer and accommodated in a battery case.

In recent years, lithium nickel cobalt manganese oxide (Li (Ni, Co, Mn) O ₂ ) has attracted attention as a positive electrode active material of this lithium ion secondary battery. This lithium nickel cobalt manganese oxide is advantageous because it provides a relatively high output compared to conventional positive electrode active materials such as lithium manganese oxide and lithium cobalt oxide, and is stable even in high-temperature electrolytes. .

  However, when this lithium nickel cobalt manganese oxide is used as the positive electrode active material and repeated high-power charge / discharge under high temperature conditions, manganese ions dissolve in the electrolyte, resulting in battery output and high-temperature cycle durability. There was a problem that would decrease. In particular, this problem is remarkable in an in-vehicle lithium ion secondary battery that is mounted on a vehicle as a power source for driving a vehicle and is expected to supply electric power with high output over a long period of time.

On the other hand, in the case of lithium manganese oxide (LiMn ₂ O ₄ ), which is also a positive electrode active material containing manganese, a problem of dissolution of manganese ions in the electrolytic solution is also known. And in order to solve such a problem in lithium manganese oxide, a layer made of lithium vanadium oxide (LiV ₂ O ₄ ) is formed on the surface of the positive electrode active material made of lithium manganese oxide, and electrolysis of manganese ions is performed. There has been proposed a technique for preventing dissolution in a liquid and suppressing a decrease in battery performance (see Patent Document 1).
JP 2000-3709 A

  However, the active material of the positive electrode material described in Patent Document 1 is a lithium manganese oxide having a spinel structure. In the first place, the lithium ion secondary battery using this spinel type lithium manganese oxide is mounted on a vehicle as a power source for driving a motor of a vehicle that is not sufficient in capacity and cycle durability and requires a long-term stable performance. In some cases, sufficient battery characteristics may not be exhibited.

  Accordingly, an object of the present invention is to provide a positive electrode material suitably used for a non-aqueous electrolyte lithium ion secondary battery that can stably supply power with high output over a long period of time.

  The present invention relates to a nonaqueous electrolyte lithium ion in which a lithium compound (hereinafter also referred to as “Li compound”) is attached to the surface of particles made of lithium nickel cobalt manganese oxide (hereinafter also referred to as “LiNiCoMn oxide”). A positive electrode material for a secondary battery is provided.

  Moreover, this invention provides the manufacturing method of said positive electrode material.

  By employing the positive electrode material of the present invention for a non-aqueous electrolyte lithium ion secondary battery, the durability of the non-aqueous electrolyte lithium ion secondary battery can be improved.

  The first positive electrode material for a non-aqueous electrolyte lithium ion secondary battery of the present invention is characterized in that a lithium compound is attached to the surface of particles made of LiNiCoMn oxide as a positive electrode active material. In the positive electrode material of the present invention, by adding a Li compound to the surface of the positive electrode active material particles, dissolution of manganese ions in the positive electrode active material into the electrolytic solution is prevented, and internal resistance associated with dissolution of manganese ions Rise and battery performance degradation can be suppressed. One reason for this is that by adding a Li compound, the Li compound functions as a physical barrier, and dissolution of manganese ions is suppressed. However, of course, other mechanisms may exist.

  Hereinafter, embodiments of the present invention will be described in detail. However, the technical scope of the present invention should be determined based on the description of the scope of claims, and is not limited to the following specific embodiments.

  LiNiCoMn oxide functions as a positive electrode active material. Accordingly, the form of the specific composition and the like is not particularly limited as long as it is an oxide that contains a lithium atom, a nickel atom, a cobalt atom, and a manganese atom and can function as a positive electrode active material. The above atoms may be substituted with other metal atoms. As an example, the following chemical formula 1:

(Where 0 <a ≦ 1.2, 0.3 ≦ b ≦ 0.9, 0.25 ≦ c ≦ 0.6, 0.25 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.3, 1.5 ≦ f ≦ 2.2, 0 ≦ g ≦ 0.5, and M is Al, M
one or more atoms selected from the group consisting of g, Ca, Ti, V, Cr, Fe and Ga, and N is one or two selected from the group consisting of F, Cl and S When there are two or more kinds of atoms and M and / or N are two or more kinds of atoms, e and / or g is a total value of two or more kinds of atoms. )
The composition shown by is illustrated. The composition of the LiNiCoMn oxide can be measured by, for example, ICP (inductively coupled plasma) emission spectroscopy, atomic absorption photometry, X-ray fluorescence, chelate titration, and particle analyzer analysis. Other analysis methods may be employed as long as the exact composition is measured, and this is the same for the measurement of other parameters described later.

  The average particle diameter of the particles made of LiNiCoMn oxide is preferably 0.1 to 20 μm from the viewpoint of reactivity as the positive electrode active material and cycle durability. The particles may be secondary particles formed by aggregation of primary particles. In such a form, the average particle diameter of the primary particles constituting the secondary particles is preferably 0.01 to 5 μm. These average particle diameters can be measured by, for example, observation using a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like.

  The shape of the particles made of LiNiCoMn oxide is not limited to a spherical shape, and may be a plate shape, a needle shape, a column shape, a square shape, or the like. The shape of the particles can be appropriately selected in consideration of desired battery characteristics (for example, charge / discharge characteristics and cycle durability). When the particle shape is other than spherical, the particle shape is not uniform. In such a case, the absolute maximum length of the particle is defined as the average particle size of the particle. Here, the “absolute maximum length” means the maximum distance L among the distances between any two points on the outline of the particle 1 as shown in FIG. When measuring the absolute maximum length, it is preferable to use the average value of the absolute maximum length of each particle present in a certain region of the electron micrograph. Alternatively, when the LiNiCoMn oxide used in the present invention is selected by sieving, the sieve mesh (mesh through size or mesh path size) used for sieving may be set as the absolute maximum length.

  The average valence of manganese atoms present in the vicinity of the surface of particles made of LiNiCoMn oxide, which is the positive electrode active material of the positive electrode material of the present invention, is preferably +3.5 or more, more preferably +4 or more. Here, it is known that manganese atoms are easily dissolved in the electrolyte as manganese ions when the valence is +3. On the other hand, by setting the average valence of manganese atoms near the surface to +3.5 or more, the abundance of manganese atoms having a valence of +4 or more is sufficiently increased, and electrolysis of manganese ions in the positive electrode active material is performed. It is considered that dissolution in the liquid can be further suppressed. The reason for limiting to the vicinity of the surface is that if the average valence of the entire active material particles is +3.5 or more, the capacity may decrease.

  Further, “near the surface” of a particle made of LiNiCoMn oxide means a region from the surface of the particle to a depth of 1/20 of the particle diameter of the particle. For example, when the particle diameter of a particle made of LiNiCoMn oxide is 2 μm, “near the surface” of the particle is a region from the particle surface to a depth of 100 nm. Moreover, the valence of the manganese atom which exists in the surface vicinity of the particle | grains which consist of LiNiCoMn oxides can be measured by an electron energy loss spectroscopy (EELS), for example.

  Moreover, it is preferable that the particle | grains which consist of LiNiCoMn oxide contain oxygen excess type LiNiCoMn oxide in the surface vicinity. This increases the average valence of manganese atoms near the surface of the active material particles, and tends to be +3.5 or more as described above. Therefore, even in such a form, dissolution of manganese ions in the positive electrode active material into the electrolytic solution can be further suppressed. The definition of “near the surface” is the same as described above.

  “Oxygen-rich LiNiCoMn oxide” refers to a non-stoichiometric compound of LiNiCoMn oxide, which is oxygen-rich (metal-deficient). Unlike an ordinary LiNiCoMn oxide, an oxygen-excess type LiNiCoMn oxide is deficient in metal atoms in the crystal lattice and has excessive oxygen atoms. In addition, there are holes for maintaining electrical neutrality. The amount of the oxygen-excess LiNiCoMn oxide present near the surface of the particle is not particularly limited, and it is sufficient that an oxygen-excess site exists in at least a part near the surface of the particle. However, in order to further exert the above-described effects, it is preferable that more than half of the LiNiCoMn oxide near the surface of the particle, and more preferably, all be an oxygen-excess LiNiCoMn oxide.

The Li compound attached to the surface of the particles made of LiNiCoMn oxide is not particularly limited, and a conventionally known Li compound can be used. A newly developed Li compound may also be used. Specific examples of the Li compound include, for example, Li ₂ SO ₄ , Li ₃ PO ₄ , LiPON, Li ₂ O—B ₂ O ₃ , Li ₂ O—B ₂ O ₃ —LiI, Li ₂ O—SiS ₂ , Li _{2 S-SiS 2 -Li 3 PO} 4, LiCoO 2, LiMn 2 O 4, LiOH, Li 2 CO 3, Li 2 S-SiS 2, LiFePO 4, LiBr, LiI, lithium acetate, lithium acetylide ethylenediamine, lithium benzoate And lithium fluoride, lithium oxalate, lithium pyruvate, lithium stearate, lithium tartrate and the like. Among them, from the viewpoint of the diffusion constant of the lithium _{ion, Li 2 SO 4, Li 3} PO 4, LiPON, Li 2 O-B 2 O 3, Li 2 O-B 2 O 3 -LiI, Li 2 O-SiS 2 Li ₂ S—SiS ₂ —Li ₃ PO ₄ , LiCoO ₂ , LiMn ₂ O ₄ , LiOH, and Li ₂ CO ₃ may be preferably used. As for these Li compounds, only 1 type may be used independently and 2 or more types may be used together. However, it is not limited to only these forms, and other Li compounds may be used as a matter of course.

  The composition of the Li compound can be measured by, for example, ICP (inductively coupled plasma) emission spectroscopy, atomic absorption photometry, fluorescent X-ray method, chelate titration method, and particle analyzer analysis method.

  The shape of the Li compound is not particularly limited, and the shape described above for the LiNiCoMn oxide can be similarly adopted. The average particle size of the Li compound is not particularly limited, but is preferably 20 to 500 nm, more preferably 50 to 400 nm, from the viewpoint of lithium ion diffusibility.

  As described above, the valence of manganese ions near the surface of the active material particles is preferably +3.5 or more. From such a viewpoint, the Li compound to be attached is preferably a compound capable of increasing the valence of manganese ions near the surface of the active material particles. Note that any of the Li compounds listed above can increase the valence of manganese ions near the surface of the active material particles by being attached to the active material particles.

  The Li compound is preferably lithium ion conductive. This is because when a Li compound that does not have lithium ion conductivity is attached, lithium ions do not conduct at the place where the lithium compound is attached, so that the internal resistance of the positive electrode material increases and the battery performance deteriorates. All the Li compounds listed above have lithium ion conductivity.

When the Li compound has lithium ion conductivity, the conductivity is preferably 10 ⁻¹⁵ S / m or more, more preferably 10 ⁻¹² S / m or more. The lithium ion conductivity can be measured by, for example, an AC impedance method, a constant potential step method, a constant current step method, or the like.

  The specific form in which the Li compound is attached to the surface of the particles made of LiNiCoMn oxide is not particularly limited. For example, the form shown in FIG. 2 is illustrated. FIG. 2 is a schematic cross-sectional view of a positive electrode material of the present invention having a form in which a coating layer 3 made of a Li compound is formed on the surface of particles 2 made of LiNiCoMn oxide. On the other hand, the form shown in FIG. 3 can also be illustrated. FIG. 3 is a schematic perspective view of the positive electrode material of the present invention having a form in which particles 4 made of Li compound are scattered on the surface of particles 2 made of LiNiCoMn oxide. The “surface” of the particle 2 made of the LiNiCoMn oxide to which the Li compound is attached may be the surface of the primary particle or the surface of the secondary particle formed by aggregation of the primary particles. Good. If the particles 2 made of the LiNiCoMn oxide shown in FIGS. 2 and 3 are assumed to be secondary particles, FIGS. 2 and 3 are diagrams showing a form in which a Li compound is attached to the surface of the secondary particles.

  Regardless of which of the forms shown in FIGS. 2 and 3 is employed, dissolution of manganese ions in the electrolytic solution can be prevented, and an increase in internal resistance of the positive electrode material can be suppressed. Therefore, which form is adopted can be selected as appropriate in consideration of the composition of the LiNiCoMn oxide or Li compound used, desired battery performance, available manufacturing means, and the like. For example, when it is desired to effectively prevent dissolution of manganese ions from the positive electrode active material, a form in which the coating layer 3 as shown in FIG. 2 is formed can be preferably employed. On the other hand, when it is desired to react the lithium ions in the positive electrode active material directly with the electrolytic solution, a form in which particles 4 made of a Li compound are scattered on the surface as shown in FIG. 3 can be preferably employed.

  Hereinafter, each preferable form of the form shown in FIG. 2 and FIG. 3 is demonstrated.

  First, the embodiment shown in FIG. 2 will be described in detail. As described above, in the form shown in FIG. 2, the coating layer 3 made of the Li compound is formed by attaching the Li compound to the surface of the particle 2 made of the LiNiCoMn oxide.

  The thickness of the coating layer 3 is preferably 3 to 1000 nm, more preferably 5 to 1000 nm, and still more preferably 5 to 700 nm. If the thickness of the coating layer 3 is less than 3 nm, dissolution of manganese ions from the LiNiCoMn oxide that is the positive electrode active material may not be sufficiently suppressed. On the other hand, when the thickness of the coating layer 3 exceeds 1000 nm, even if the Li compound has lithium ion conductivity, the internal resistance of the positive electrode material increases, and the battery performance may be deteriorated. Note that the thickness of the coating layer 3 can be measured, for example, by observing an electron micrograph of a cross section of the positive electrode material.

  Next, the embodiment shown in FIG. 3 will be described in detail. As described above, in the embodiment shown in FIG. 3, the particles 4 made of the Li compound are scattered on the surface of the particles 2 made of the LiNiCoMn oxide.

  In such a form, the volume ratio of the particles 4 made of the added Li compound to the volume of the particles 2 made of the LiNiCoMn oxide is preferably 0.5 to 250%, more preferably 0.7 to 150%. is there. If the volume ratio of the particles made of the Li compound is less than 0.5%, the dissolution of manganese ions from the LiNiCoMn oxide that is the positive electrode active material may not be sufficiently suppressed. On the other hand, when the volume ratio of particles made of Li compound exceeds 250%, even if the Li compound has lithium ion conductivity, the internal resistance of the positive electrode material may increase and the battery performance may be deteriorated. . In addition, the said volume ratio can be measured by observing the electron micrograph of positive electrode material, for example.

Moreover, in the form shown in FIG. 3, the average particle diameter of the particles 4 made of Li compounds adhering so as to be scattered is preferably about 10 to 200 μm, more preferably 20 to 100 μm. If the average particle size of the particles 4 made of the Li compound is less than 10 μm, there is a possibility that the effect of adding the Li compound may not be sufficiently obtained. On the other hand, if the average particle size exceeds 200 μm, the effect of the adhesion may be gradually reduced, and the resistance due to the Li compound may be increased.

  It is preferable that a compound containing a divalent metal atom (hereinafter also referred to as “divalent compound”) is further attached to the surface of the positive electrode material of the present invention. By adding the divalent compound to the surface of the positive electrode material, the valence of manganese ions near the surface of the active material particles can be increased. Therefore, according to such a form, dissolution of manganese ions in the positive electrode active material into the electrolytic solution can be further suppressed. The form in which the divalent compound is attached to the surface of the positive electrode material is not particularly limited, and the form shown in FIGS. 2 and 3 described above with respect to the form in which the Li compound is attached to the surface of the LiNiCoMn oxide particles. Can be adopted as well.

  For example, when a coating layer made of a divalent compound is formed on the surface of the positive electrode material by adding a divalent compound, the thickness of the coating layer made of the divalent compound is preferably 3 to 1000 nm, more preferably Is 5 to 500 nm. In addition, when the particles made of the divalent compound are scattered so as to be scattered, the volume ratio of the particles made of the added divalent compound to the volume of the positive electrode material (LiNiCoMn oxide to which the Li compound is added) is , Preferably 0.5 to 30%, more preferably 0.6 to 20%.

  In some cases, a form in which both particles made of a Li compound and particles made of a divalent compound are scattered on the surface of particles made of a LiNiCoMn oxide may be employed.

The divalent metal atom contained in the divalent compound is not particularly limited as long as it is a metal atom having a valence of +2, but for example, alkaline earth metal atoms such as Mg, Ca, Sr, Ba, Zn, Examples thereof include Cu, Fe, Ni, V, Nb, Co, Ge, Si, In, Pb, and Mn. The divalent compound is not particularly limited as long as it is a compound containing a divalent metal atom as described above. Specific examples of the divalent compound include MgO, BaO, SrO, CaO, CaCO ₃ , SrCO ₃ , BaCO ₃ , mgCO ₃ , CaSO ₄ , BaSO ₄ , MgSO ₄ , and Ca as compounds containing an alkaline earth metal atom. (NO ₃ ) ₂ , Sr (NO ₃ ) ₂ , Ba (NO ₃ ) ₂ , Mg (NO ₃ ) _{2 and the} like, and other compounds include ZnO, CuO, FeO, NiO, VO, NbO, CoO, GeO, SiO, InO, PbO, CoCO ₃ , PbCO ₃ , MnCO ₃ , FeCO ₃ , NiCO ₃ , CoSO ₄ , PbSO ₄ , FeSO ₄ , MnSO ₄ , CuSO ₄ , Co (NO ₃ ) ₂ , Fe (NO ₃ ) _{2, Cu (NO 3) 2} , Pb (NO 3) 2, Ni (NO 3) 2, Mn (NO 3) 2 and the like It is.

  Then, the manufacturing method of the positive electrode material of this invention is demonstrated. The positive electrode material of the present invention is produced, for example, by firing a LiNiCoMn oxide raw material to prepare a LiNiCoMn oxide (firing step), and attaching a Li compound to the surface of the LiNiCoMn oxide particles (an attaching step). Can be done.

  Hereinafter, although one preferable form of said manufacturing method is demonstrated in detail, the technical scope of this invention is not restrict | limited only to the following form.

  First, the firing process will be described.

  In the firing step, as described above, the LiNiCoMn oxide raw material is fired to prepare the LiNiCoMn oxide.

In the firing step, first, a raw material for LiNiCoMn oxide is prepared. The raw material is not particularly limited as long as a LiNiCoMn oxide can be prepared by firing, and may be a single compound or a mixture of two or more compounds. In addition, about the composition of each component in a raw material, it does not restrict | limit in particular, According to the desired composition of the LiNiCoMn oxide obtained, it can adjust suitably. Moreover, when a raw material is a mixture of 2 or more types of compounds, the mixing means for mixing 2 or more types of compounds is not specifically limited, A conventionally well-known means may be employ | adopted. At this time, wet mixing is preferably used in order to obtain a uniform mixture. The wet-mixed raw material may be coprecipitated by, for example, a coprecipitation method and fired as described later. In some cases, only raw materials having a uniform particle diameter may be selected by sieving the raw materials and used for production.

  Examples of the raw material include a mixture of a lithium compound, a nickel compound, a cobalt compound, and a manganese compound.

  That is, the second of the present invention is a firing step of firing a mixture of a lithium compound, a nickel compound, a cobalt compound, and a manganese compound to obtain particles made of lithium nickel cobalt manganese oxide, and the lithium nickel cobalt manganese oxide. And a method for producing a positive electrode material for a non-aqueous electrolyte lithium ion secondary battery, comprising an attaching step of attaching a lithium compound to the surfaces of the particles.

  By firing such a raw material, a LiNiCoMn oxide having excellent dispersibility of constituent atoms, high crystallinity, and high reactivity as a positive electrode active material can be prepared. In addition, there is no restriction | limiting in particular about the specific form of said lithium compound, a nickel compound, a cobalt compound, and a manganese compound, For example, forms, such as an oxide and carbonate, are mentioned.

  The firing conditions are not particularly limited as long as a LiNiCoMn oxide can be obtained. As an example, the firing temperature is about 600 to 900 ° C, preferably 700 to 880 ° C. The firing time is about 6 to 36 hours, preferably 12 to 30 hours. There are no particular restrictions on the atmospheric conditions during firing, but firing may be performed in an oxygen atmosphere. By performing firing in an oxygen atmosphere, excess oxygen is introduced near the surface of the obtained LiNiCoMn oxide, and an oxide containing an oxygen-rich LiNiCoMn oxide near the surface can be prepared.

  After the above baking step, the obtained LiNiCoMn oxide is cooled to about room temperature. By quenching, LiNiCoMn oxide particles having a small average particle diameter can be obtained, and further, the average valence of manganese atoms existing near the surface of the particles made of the LiNiCoMn oxide can be increased. The specific cooling rate is preferably 150 ° C./min or more, more preferably 170 ° C./min or more. At this time, when the cooling rate is increased, an oxide having a smaller average particle diameter can be obtained. The rapid cooling is preferably performed in an oxygen atmosphere. Thereby, excess oxygen can be introduced near the surface of the oxide.

  Note that an annealing step may be performed in an oxygen atmosphere separately from the above-described firing step in order to reliably introduce excess oxygen near the surface of the obtained oxide and allow the oxygen-excess LiNiCoMn oxide to exist. At this time, the annealing temperature is about 250 to 600 ° C., and the annealing time is about 30 minutes to 12 hours. The oxygen pressure in the oxygen atmosphere is preferably about 1 to 100 atm, more preferably 1 to 50 atm.

  The apparatus used in the above baking process or annealing process is not particularly limited, and a conventionally known baking furnace, autoclave, chamber of a film forming apparatus, and the like can be appropriately employed.

  If necessary, only particles having a desired average particle diameter may be selected by sieving the obtained LiNiCoMn oxide particles after the firing step or the annealing step.

  As mentioned above, although the form which bakes a raw material and prepares LiNiCoMn oxide itself was demonstrated, it is not restrict | limited only to such a form. Depending on the case, a commercially available LiNiCoMn oxide may be purchased, and an annealing process etc. may be performed as needed and used for the below-mentioned attachment process.

  Next, the attaching process will be described.

  In the attaching step, as described above, the Li compound is attached to the surface of the LiNiCoMn oxide particles prepared in the above firing step to obtain the positive electrode material of the present invention.

  In the attaching step, first, the LiNiCoMn oxide particles prepared above and the Li compound to be attached are prepared. Since these preferable forms are as described above, the description thereof is omitted here.

  The specific method of attachment is not particularly limited, and conventionally known attachment techniques can be appropriately employed. Whether the form in which the coating layer 3 made of the Li compound is formed as shown in FIG. 2 or the form in which the particles 4 made of the Li compound are scattered as shown in FIG. 3 is used depends on the LiNiCoMn used. It can be appropriately controlled by adjusting the volume ratio and average particle size of the oxide particles and the Li compound.

  As a method for attaching the Li compound, a dry method can be preferably employed. That is, the LiNiCoMn oxide prepared in the firing step and the Li compound are dry mixed to attach the Li compound to the surface of the oxide particles.

  The specific method of the dry mixing is not particularly limited, and examples thereof include a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, a pulsed laser deposition (PLD) method, and a sputtering method. The These techniques are particularly advantageous for manufacturing a positive electrode material in a form in which the coating layer 3 shown in FIG. 2 is formed. Also, for example, hybridization system (manufactured by Nara Machinery Co., Ltd.), cosmos (manufactured by Kawasaki Heavy Industries, Ltd.), mechanofusion (manufactured by Hosokawa Micron Corporation), surfing system (manufactured by Nippon Pneumatic Industrial Co., Ltd.), mechanomill, speed Techniques such as a kneader, a speed mill, and a Spira coater (Okada Seiko Co., Ltd.) may also be used. These techniques are particularly advantageous for the production of the cathode material in the dotted form shown in FIG. However, the method is not limited to the above-described method, and other methods may be used as a matter of course.

  If necessary, the obtained particles may be heated. By heating, the attached Li compound can be firmly bonded to the surface of the active material particles.

  Although the dry attachment method has been described in detail above, a wet attachment method may be used depending on circumstances. In such a case, it is good to perform an attaching process simultaneously in the baking process mentioned above. That is, when the LiNiCoMn oxide raw material is wet-mixed in the above firing step, the Li compound is mixed simultaneously, co-precipitated, and further fired to form a LiNiCoMn oxide particle with the Li compound attached to the surface. (The positive electrode material of the present invention) is obtained.

  Thereafter, a divalent compound may be added as necessary. The preferred form of the divalent compound is as described above. Moreover, about the attachment method of a bivalent compound, the method demonstrated above about the attachment of Li compound can be used similarly.

The positive electrode material of the present invention is suitably used for the positive electrode of a non-aqueous electrolyte lithium ion secondary battery. That is, the third of the present invention is a positive electrode using the first positive electrode material for a non-aqueous electrolyte lithium ion secondary battery of the present invention. As described above, by using the positive electrode material of the present invention, an increase in internal resistance and a decrease in battery performance can be suppressed. Hereinafter, although the preferable one form of the positive electrode for nonaqueous electrolyte lithium ion secondary batteries using the positive electrode material of this invention is demonstrated in detail, the technical scope of this invention is not restrict | limited only to the following form.

  The positive electrode of the present invention is characterized by having a current collector and an active material layer located on the current collector, and including the first positive electrode material of the present invention in the active material layer. In the positive electrode of the present invention, a battery reaction proceeds in the active material layer, and electrons generated by the battery reaction perform electrical work on an external load.

  Hereinafter, the current collector and the active material layer constituting the positive electrode of the present invention will be described.

  The current collector is made of a conductive material such as aluminum foil, copper foil, or stainless steel (SUS) foil. A typical thickness of the current collector is 10 to 50 μm. However, a current collector having a thickness outside this range may be used. The magnitude | size of an electrical power collector is determined according to the use application of the positive electrode of this invention. If a large positive electrode used for a large battery is produced, a current collector having a large area is used. If a small positive electrode is produced, a current collector with a small area is used.

  The active material layer is located on the surface of the current collector and includes the positive electrode material of the present invention. Since the preferable form of the positive electrode material of the present invention contained in the active material layer is as described in the first column of the present invention, detailed description is omitted here.

The active material layer may contain a positive electrode active material other than the positive electrode material of the present invention, if necessary. There is no restriction | limiting in particular as positive electrode active materials other than the positive electrode material of this invention, According to the desired battery performance etc., a conventionally well-known compound can be used suitably as a positive electrode active material. An example is a composite oxide of lithium and a transition metal. Specifically, Li—Mn composite oxides such as LiMn ₂ O ₄ , Li—Co composite oxides such as LiCoO _2, and Li—Cr composite oxides such as Li ₂ Cr ₂ O ₇ and Li ₂ CrO _4. And Li-Fe-based composite oxides such as LiFeO ₂ are exemplified. In addition, a compound in which a part of the transition metal contained in these composite oxides is substituted with another element may be used. Besides these, lithium phosphate compounds such as LiFePO ₄ , lithium sulfate compounds, oxides and sulfides of transition metals such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ , PbO ₂ , AgO NiOOH or the like may be included in the active material layer.

  In the active material layer, substances other than the above substances may also be included as necessary. For example, a binder, a conductive additive, a lithium salt (supporting electrolyte), an ion conductive polymer, and the like can be included. In some cases, a polymerization initiator for polymerizing the ion conductive polymer contained in the active material layer may be included.

  Examples of the binder include polyvinylidene fluoride (PVdF) and a rubber-based binder.

  A conductive support agent means the additive mix | blended in order to improve the electroconductivity of the active material layer in an electrode. Examples of the conductive aid include carbon powders such as acetylene black and graphite, carbon fibers such as mesophase carbon, non-graphitizable carbon, ketjen black, and vapor grown carbon fiber (VGCF).

As a lithium salt (supporting electrolyte), LiBETI (lithium bis (perfluoroethylenesulfonylimide); Li (C ₂ F ₅ SO ₂ ) ₂ N), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiBOB and the like.

  Examples of the ion conductive polymer include polyethylene oxide (PEO) -based and polypropylene oxide (PPO) -based polymers. Here, the ion conductive polymer may be the same as or different from the ion conductive polymer used as the electrolyte in the electrolyte layer of the non-aqueous electrolyte lithium ion secondary battery in which the positive electrode of the present invention is employed. Good, but preferably the same.

  The polymerization initiator is blended to act on the crosslinkable group of the ion conductive polymer and advance the crosslinking reaction. It is classified into a thermal polymerization initiator, a photopolymerization initiator and the like according to an external factor for acting as an initiator. Examples of the polymerization initiator include azobisisobutyronitrile (AIBN), which is a thermal polymerization initiator, and benzyl dimethyl ketal (BDK), which is a photopolymerization initiator.

  The compounding ratio of the components contained in the active material layer and the size (area) of the active material layer are not particularly limited. These forms can be adjusted by appropriately referring to known knowledge about the active material layer of the electrode.

  There is no restriction | limiting in particular about the manufacturing method of the positive electrode of this invention, It can manufacture by referring the conventionally well-known knowledge regarding manufacture of the positive electrode of a battery suitably. For example, the positive electrode material of the present invention may be prepared by preparing a positive electrode material slurry containing the positive electrode material of the present invention, applying the positive electrode material slurry to the surface of the current collector, and drying the slurry.

  Hereinafter, a preferred embodiment of the above manufacturing method will be described in detail.

  First, the process for preparing the positive electrode material slurry will be described.

  In this step, the positive electrode material slurry is prepared by adding and dispersing the first positive electrode material of the present invention in a suitable slurry viscosity adjusting solvent. Further, if necessary, in the positive electrode material slurry, in addition to the positive electrode active material other than the positive electrode material of the present invention, a binder, a conductive auxiliary agent, a lithium salt (supporting electrolyte), an ion conductive polymer, a polymerization initiator, etc. These components may be added. Here, since the preferable form of each component contained in a positive electrode material slurry is as having demonstrated above, description is abbreviate | omitted here.

  In addition, when preparing positive electrode material slurry, the order of addition of each component is not particularly limited. For example, after preparing a mixture of all components other than the solvent contained in the slurry, a solvent may be added to the mixture and mixed to prepare a positive electrode material slurry. In addition, after preparing a mixture of several components other than the solvent contained in the slurry, a solvent is added to the mixture, and after mixing, the remaining components are further added and mixed to prepare a positive electrode material slurry May be. At this time, the apparatus used for adding or mixing each component is not particularly limited, and examples thereof include a homomixer.

  Next, the process of applying the positive electrode material slurry will be described.

  In this step, the positive electrode material slurry prepared in the above step is applied onto an appropriate current collector. The method for applying the positive electrode material slurry onto the current collector is not particularly limited, and a conventionally known method such as a coater can be used. If possible, printing methods such as spray printing and ink jet printing can also be used. Next, the current collector coated with the positive electrode material slurry is dried to remove the solvent contained in the slurry. For drying, for example, a vacuum dryer can be used. Moreover, since drying conditions change according to the various properties of the slurry, they cannot be uniquely determined, but are usually about 60 to 130 ° C. for about 5 to 60 minutes.

  Here, when a polymerization initiator for polymerizing the ion conductive polymer contained in the active material layer is contained in the active material layer, the ion conductive polymer is then polymerized (crosslinked) by various methods. To complete the positive electrode. The polymerization (crosslinking) method at this time is not particularly limited, and can be appropriately selected according to the kind of the polymerization initiator contained in the active material layer. Examples thereof include thermal polymerization, photo (ultraviolet) polymerization, radiation polymerization, and electron beam polymerization. The apparatus and conditions for polymerizing (crosslinking) are not particularly limited, and conventionally known apparatuses and conditions can be used.

  Moreover, if necessary, you may perform press operation to the positive electrode manufactured by said method. By performing this pressing operation, the surface of the obtained positive electrode can be further flattened. The apparatus and conditions used for the press operation are not particularly limited, and conventionally known apparatuses and methods can be appropriately used.

  In an industrial production process, in order to improve productivity, a process of producing a positive electrode larger than the final battery size and cutting it into a predetermined size may be employed.

  The positive electrode of the present invention is suitably used for a non-aqueous electrolyte lithium ion secondary battery. That is, the fourth of the present invention is a battery using the third nonaqueous electrolyte lithium ion secondary battery of the present invention. In such a battery, as described above, an increase in internal resistance and a decrease in battery performance can be suppressed. Hereinafter, although the preferable one form of the nonaqueous electrolyte lithium ion secondary battery using the positive electrode of this invention mentioned above is demonstrated in detail, the technical scope of this invention is not restrict | limited only to the following form.

  The battery of the present invention is characterized in that the third positive electrode of the present invention is used as the positive electrode, that is, the first positive electrode material of the present invention is included in the positive electrode.

  In a general battery, a positive electrode, an electrolyte layer, and a negative electrode are arranged in this order, and these are sealed in an exterior such as a laminate sheet. The specific form of the negative electrode and the form of the electrolyte contained in the electrolyte layer are not particularly limited, and a conventionally known form can be adopted. For example, the negative electrode has a configuration in which an active material layer containing a negative electrode active material such as a carbon material such as graphite or hard carbon is formed on a current collector similar to that used in the positive electrode of the present invention. Can be exemplified. The electrolyte may be a liquid electrolyte, a solid electrolyte, or a gel electrolyte. When the electrolyte is included, the electrolyte is a non-aqueous electrolyte.

  When the battery element is accommodated inside the exterior, the battery element is accommodated in such a manner that the tab is pulled out of the exterior. And in order to ensure internal sealing performance, the exterior of the site | part in which the battery element is not accommodated is sealed. As the exterior, a polymer metal composite film can be used. The polymer metal composite film is a film in which at least a metal thin film and a resin film are laminated. By adopting such an exterior, a thin laminated battery can be formed.

The battery of the present invention is a lithium ion secondary battery. Further, a bipolar lithium ion secondary battery (bipolar battery) is preferable. For reference, FIG. 4 shows a schematic sectional view of a non-bipolar lithium ion secondary battery (general lithium ion battery), and FIG. 5 shows a schematic sectional view of a bipolar lithium ion secondary battery (bipolar battery). Show. As can be seen from FIGS. 4 and 5, the general lithium ion battery and the bipolar battery differ only in the arrangement of the electrodes. Generally, a general lithium ion battery is a high-energy battery having a large battery capacity, and is excellent in performance of supplying power for a long period of time. On the other hand, a bipolar battery is a battery with a high output density and is excellent in performance of supplying a large amount of power in a short time. Therefore, which form is adopted can be appropriately determined according to the form of required power. The technical scope of the present invention is not limited to the contents of these drawings.

  A plurality of the batteries of the present invention, or at least one battery of the present invention and another type of battery are connected in parallel connection, series connection, parallel-series connection, or series-parallel connection to form an assembled battery. Also good. That is, the fifth aspect of the present invention is an assembled battery using the battery of the present invention. Thereby, it becomes possible to respond to the demand for the battery capacity and output for each purpose of use relatively inexpensively without producing a new battery. The specific form at the time of manufacturing an assembled battery is not specifically limited, The well-known knowledge currently used about an assembled battery can be employ | adopted. Furthermore, a plurality of assembled batteries of the present invention may be connected to form a composite assembled battery.

  The battery and the assembled battery of the present invention, and the composite assembled battery including these can be preferably used in a vehicle as a driving power source or an auxiliary power source. That is, the sixth aspect of the present invention is a vehicle equipped with the battery of the present invention or the assembled battery of the present invention.

  A vehicle on which the battery or the assembled battery of the present invention and the composite assembled battery including these can be mounted is not particularly limited, but an electric vehicle, a fuel cell vehicle, and a hybrid vehicle thereof are preferable.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

<Example 1>
Example 1-1
<Preparation of positive electrode material>
As raw materials for the positive electrode active material, lithium carbonate (average particle size: 3.2 μm) (1), nickel carbonate (average particle size: 3.0 μm), cobalt carbonate (average particle size: 3.5 μm), and manganese carbonate A mixture (2) having an average particle diameter of 2.5 μm was prepared. Here, the mixing of the three components constituting the mixture (2) was performed so that the number of moles of nickel atoms, cobalt atoms, and manganese atoms were equal.

Subsequently, the above (1) and (2) are mixed so that the ratio of the number of moles of lithium atoms to the total number of moles of nickel, cobalt, and manganese atoms is 1.2: 1. The mixture was further mixed for 24 hours in a ball mill. Then, it baked at 850 degreeC under oxygen atmosphere for 24 hours. After firing, while flowing oxygen, it was cooled to room temperature at a cooling rate of 170 ° C./min to prepare LiNiCoMn oxide as a positive electrode active material. As a result of analyzing the composition of the obtained LiNiCoMn oxide by ICP emission spectroscopy, it was Li _1.05 Ni _0.35 Co _0.32 Mn _0.33 O ₂ . Moreover, it was 5 micrometers when the average particle diameter of the obtained LiNiCoMn oxide was measured.

  Subsequently, lithium sulfate (average particle diameter: 100 nm), which is a lithium compound, was prepared. Using this lithium sulfate, the surface of the LiNiCoMn oxide particles prepared above was coated with a thickness of 3 nm to prepare a positive electrode material having the form shown in FIG. Specifically, lithium sulfate was impregnated on the surface of the active material particles using a mechano-fusion method, and then annealed at 300 ° C. for 5 hours in an air atmosphere to coat the surfaces of the active material particles with lithium sulfate. .

<Preparation of positive electrode>
The positive electrode material (75 parts by mass) prepared above, polyvinylidene fluoride (PVdF) (15 parts by mass) as a binder, and acetylene black (10 parts by mass) as a conductive auxiliary agent are prepared, and an appropriate amount of slurry viscosity is prepared. N-methyl-2-pyrrolidone (NMP), which is a adjusting solvent, was added and sufficiently stirred and mixed to prepare a positive electrode material slurry.

  The positive electrode material slurry prepared above was applied onto an aluminum foil (thickness: 20 μm) as a positive electrode current collector with an applicator, and dried by heating to about 80 ° C. with a vacuum dryer. For use in a coin-type battery, the obtained electrode was punched out at 15 mmφ, and further dried under high vacuum conditions at 90 ° C. for 6 hours to produce a positive electrode. Note that the thickness of the positive electrode layer formed on the current collector was 50 μm.

<Production of negative electrode>
Carbon (average particle size: 10 μm) (85 parts by mass) of a carbon-based material as a negative electrode active material, polyvinylidene fluoride (PVdF) (5 parts by mass) as a binder, and acetylene black (8 masses) as a conductive auxiliary agent %) And vapor grown carbon fiber (VGCF) (2% by mass), add an appropriate amount of slurry viscosity adjusting solvent N-methyl-2-pyrrolidone (NMP), and stir and mix thoroughly. A negative electrode slurry was prepared.

  The negative electrode slurry prepared above was applied onto a copper foil (thickness: 20 μm) as a negative electrode current collector by an applicator, and dried by heating to about 80 ° C. with a vacuum dryer. For use in a coin-type battery, the obtained electrode was punched out at 16 mmφ, and further dried under high vacuum conditions at 90 ° C. for 6 hours to produce a negative electrode. The thickness of the negative electrode layer formed on the current collector was 80 μm.

<Preparation of electrolyte layer>
As the separator, a polypropylene (PP) microporous separator (average pore diameter: 800 nm, porosity: 35%, thickness: 30 μm) was prepared. On the other hand, an equal volume mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) containing 1.0 M LiPF ₆ was prepared as a non-aqueous electrolyte. Similarly, the above electrolyte solution was injected into the separator to produce an electrolyte layer.

<Production of coin-type bipolar cell>
Using the positive electrode, negative electrode, and electrolyte layer prepared above, a coin type bipolar cell was prepared. At this time, the capacity balance between the positive and negative electrodes was controlled by the positive electrode.

<Measurement of change in internal resistance due to storage>
Immediately after producing the above coin-type bipolar battery, the battery was charged to a voltage of 4.1 V with a current of 0.2 C in terms of positive electrode, and constant voltage charging was performed for 12 hours. Thereafter, the charging was stopped and stored at room temperature for one week. After storage for 1 week, the battery was once discharged to 2.5 V, and again charged with constant current-constant voltage at a current of 0.2 C to 3.6 V for 12 hours. Thereafter, the initial internal resistance was measured by direct current.

  Subsequently, constant current-constant voltage charging was performed at a current of 0.2 C up to 4.1 V for 12 hours. After the charging was stopped, the battery was stored at 60 ° C. for one month at a voltage of 4.1 V. Thereafter, the internal resistance (internal resistance after storage) was measured by direct current in the same manner as described above, and the internal resistance increase rate was calculated according to the following formula 1. The results are shown in Table 1 below.

Examples 1-2 to 1-9
A positive electrode material was prepared in the same manner as in Example 1-1 except that the thickness of lithium sulfate covering the surfaces of the LiNiCoMn oxide particles was changed to the values shown in Table 1 below, and a coin-type bipolar electrode was prepared. A formula cell was prepared and the change in internal resistance due to storage was measured. The results are shown in Table 1 below.

<Comparative example>
A coin-type bipolar cell was produced in the same manner as in Example 1-1 except that the surface of the LiNiCoMn oxide particles was not coated with lithium sulfate, which is a lithium compound, and the change in internal resistance due to storage Was measured. The results are shown in Table 1 below.

<Example 2>
Example 2-1
The above Example 1-5 is referred to as Example 2-1.

Examples 2-2 to 2-21
A positive electrode material was prepared in the same manner as in Example 2-1, except that the compound shown in Table 2 below was used instead of lithium sulfate as the lithium compound for coating the surface of the LiNiCoMn oxide particles. A coin-type bipolar cell was prepared, and the change in internal resistance due to storage was measured. The results are shown in Table 2 below.

<Example 3>
Example 3-1.
The mechano-fusion method is used to attach lithium sulfate, which is a lithium compound, to the surface of LiNiCoMn oxide particles, which are positive electrode active materials. At this time, 0.5 volume% lithium sulfate is attached to the LiNiCoMn oxide. The positive electrode material was prepared by the same method as in Example 1-1 except that the positive electrode material having the form shown in FIG. 3 was prepared, and a coin-type bipolar battery was prepared. It was measured. The results are shown in Table 3 below.

Examples 3-2 to 3-11
A positive electrode material was prepared in the same manner as in Example 3-1, except that the amount of lithium sulfate applied was changed to the value shown in Table 3 below, and a coin-type bipolar battery was prepared. The change of was measured. The results are shown in Table 3 below.

<Example 4>
Example 4-1
The above Example 3-4 is referred to as Example 4-1.

Examples 4-2 to 4-21
A positive electrode material was prepared in the same manner as in Example 4-1, except that the compound shown in Table 4 below was used instead of lithium sulfate as the lithium compound to be attached to the surface of the LiNiCoMn oxide particles. A coin-type bipolar cell was prepared, and the change in internal resistance due to storage was measured. The results are shown in Table 4 below.

<Example 5>
Example 5-1
The obtained LiNiCoMn oxide was charged into an autoclave and annealed at 500 ° C. for 12 hours under an oxygen pressure of 1 atm to introduce excess oxygen to the surface of the LiNiCoMn oxide as a positive electrode active material, and then LiNiCoMn oxidation. The positive electrode material was prepared by the same method as in Example 1-5, except that the surface of the particles of the product was coated with lithium sulfate, which is a lithium compound, and a coin-type bipolar battery was prepared. Changes were measured. The results are shown in Table 5 below.

Examples 5-2 to 5-5
Except that the oxygen pressure during annealing was set to the values shown in Table 5 below, a positive electrode material was prepared by the same method as in Example 5-1, a coin-type bipolar battery was prepared, and internal resistance due to storage The change of was measured. The results are shown in Table 5 below.

<Example 6>
Example 6-1
A positive electrode material was prepared in the same manner as in Example 1-5, except that the surface of the obtained positive electrode material particles was further coated with zinc oxide (average particle size: 100 nm), which is a divalent compound, and a coin was prepared. A type bipolar cell was prepared and the change in internal resistance due to storage was measured. The results are shown in Table 6-1 below. The positive electrode material was attached with zinc oxide by a mechano-fusion method. After the attachment, annealing was performed at 300 ° C. for 5 hours in an oxygen atmosphere to coat the surface of the positive electrode material with zinc oxide. Moreover, the coating amount of zinc oxide was about 5% by volume with respect to the positive electrode material before coating.

Examples 6-2 to 6-45
A positive electrode material was prepared in the same manner as in Example 6-1 except that instead of zinc oxide, the compound shown in Table 6 below was used as a divalent compound for further covering the surface of the positive electrode material particles. Then, a coin type bipolar cell was prepared, and the change in internal resistance due to storage was measured. The results are shown in Tables 6-1 and 6-2 below.

  From the above results, it is shown that an increase in the internal resistance of the positive electrode material is suppressed by attaching a Li compound to the surface of the particles made of LiNiCoMn oxide. Therefore, it is expected that by using such a positive electrode material, an increase in the internal resistance of the battery is suppressed, and as a result, a decrease in battery performance is effectively prevented.

  Moreover, the comparison between Example 1 and Example 5 shows that the increase in internal resistance can be further suppressed by increasing the oxygen in the vicinity of the surface of the particles made of the LiNiCoMn oxide, which is the positive electrode active material. .

  Furthermore, from the comparison between Example 1 and Example 6, it is possible to further suppress the increase in internal resistance by further attaching a compound containing a divalent metal atom to the surface of the positive electrode material of the present invention. Indicated.

It is explanatory drawing for demonstrating the absolute maximum length used when measuring the particle size of particle | grains. It is a schematic cross section of the positive electrode material of the present invention having a form in which a coating layer made of a Li compound is formed on the surface of particles made of LiNiCoMn oxide. 1 is a schematic perspective view of a positive electrode material of the present invention having a form in which particles made of a Li compound are scattered on the surface of particles made of a LiNiCoMn oxide. It is a schematic sectional drawing of the lithium ion secondary battery (general lithium ion battery) which is not a bipolar type. It is a schematic sectional drawing of a bipolar type lithium ion secondary battery.

Explanation of symbols

1 particle (including irregularly shaped particles),
2 particles made of LiNiCoMn oxide,
A coating layer comprising 3 Li compound,
Particles made of 4 Li compound,
10 General lithium ion battery,
13 positive electrode,
15 negative electrode,
17 electrolyte layer,
21 positive electrode current collector,
23 negative electrode current collector,
25 positive electrode tab,
27 negative electrode tab,
29 Exterior,
30 bipolar battery,
31 current collector,
33 single battery (cell),
35 insulation layer,
37 laminate (battery element),
L Maximum distance.

Claims (15)

  A positive electrode material for a non-aqueous electrolyte lithium ion secondary battery, wherein a lithium compound is attached to the surface of particles made of lithium nickel cobalt manganese oxide.   2. The positive electrode material for a non-aqueous electrolyte lithium ion secondary battery according to claim 1, wherein an average particle diameter of the particles made of the lithium nickel cobalt manganese oxide is 0.1 to 20 μm.   The attached lithium compound forms a coating layer that covers the particles of the lithium nickel cobalt manganese oxide, and the thickness of the coating layer is 3 to 1000 nm. Positive electrode material for non-aqueous electrolyte lithium ion secondary battery.   The nonaqueous electrolyte according to any one of claims 1 to 3, wherein a volume ratio of the attached lithium compound to a volume of particles made of the lithium nickel cobalt manganese oxide is 0.5 to 250%. Positive electrode material for lithium ion secondary battery.   The positive electrode material for a non-aqueous electrolyte lithium ion secondary battery according to any one of claims 1 to 4, wherein the lithium compound attached is a compound having lithium ion conductivity. The attached lithium compounds are Li ₂ SO ₄ , Li ₃ PO ₄ , LiPON, Li ₂ O—B ₂ O ₃ , Li ₂ O—B ₂ O ₃ —LiI, Li ₂ O—SiS ₂ , Li ₂ S. _{-SiS 2 -Li 3 PO 4, LiCoO} 2, LiMn 2 O 4, LiOH, and is one or more compounds selected from the group consisting of _Li 2 CO _3, claim 1 The positive electrode material for a non-aqueous electrolyte lithium ion secondary battery according to item 1.   The non-aqueous electrolyte lithium ion secondary according to any one of claims 1 to 6, wherein an average valence of manganese atoms existing near the surface of the particles comprising the lithium nickel cobalt manganese oxide is +3.5 or more. Positive electrode material for batteries.   8. The non-aqueous electrolyte lithium ion secondary battery according to claim 1, wherein the particles made of lithium nickel cobalt manganese oxide include oxygen-excess lithium nickel cobalt manganese oxide in the vicinity of the surface thereof. 9. Positive electrode material.   Furthermore, the positive electrode material for nonaqueous electrolyte lithium ion secondary batteries of any one of Claims 1-8 by which the compound containing a bivalent metal atom is attached.   The positive electrode for nonaqueous electrolyte lithium ion secondary batteries using the positive electrode material for nonaqueous electrolyte lithium ion secondary batteries of any one of Claims 1-9.   The nonaqueous electrolyte lithium ion secondary battery using the positive electrode for nonaqueous electrolyte lithium ion secondary batteries of Claim 10.   An assembled battery using the nonaqueous electrolyte lithium ion secondary battery according to claim 11.   A vehicle on which the nonaqueous electrolyte lithium ion secondary battery according to claim 11 or the assembled battery according to claim 12 is mounted. A firing step of firing particles of a lithium compound, a nickel compound, a cobalt compound, and a manganese compound to obtain particles made of lithium nickel cobalt manganese oxide;
An attaching step of attaching a lithium compound to the surface of the particles comprising the lithium nickel cobalt manganese oxide;
The manufacturing method of the positive electrode material for non-aqueous electrolyte lithium ion secondary batteries which has this.   The manufacturing method of Claim 14 which further has a cooling process which cools the particle | grains which consist of lithium nickel cobalt manganese oxide obtained in the said baking process at a speed | rate of 150 degrees C / min or more in an oxidizing atmosphere.