WO2017164237A1 - Matière active d'électrode positive pour pile secondaire à électrolyte non aqueux et son procédé de fabrication, pâte de matière d'électrode positive pour pile secondaire à électrolyte non aqueux, et pile secondaire à électrolyte non aqueux - Google Patents

Matière active d'électrode positive pour pile secondaire à électrolyte non aqueux et son procédé de fabrication, pâte de matière d'électrode positive pour pile secondaire à électrolyte non aqueux, et pile secondaire à électrolyte non aqueux Download PDF

Info

Publication number
WO2017164237A1
WO2017164237A1 PCT/JP2017/011450 JP2017011450W WO2017164237A1 WO 2017164237 A1 WO2017164237 A1 WO 2017164237A1 JP 2017011450 W JP2017011450 W JP 2017011450W WO 2017164237 A1 WO2017164237 A1 WO 2017164237A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
active material
electrode active
electrolyte secondary
aqueous electrolyte
Prior art date
Application number
PCT/JP2017/011450
Other languages
English (en)
Japanese (ja)
Inventor
治朗 岡田
相田　平
小向　哲史
Original Assignee
住友金属鉱山株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2016248296A external-priority patent/JP7135269B2/ja
Application filed by 住友金属鉱山株式会社 filed Critical 住友金属鉱山株式会社
Priority to CN201780030656.XA priority Critical patent/CN109155413B/zh
Priority to US16/086,746 priority patent/US20190051929A1/en
Publication of WO2017164237A1 publication Critical patent/WO2017164237A1/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a positive electrode active material for a non-aqueous electrolyte secondary battery and a method for producing the same, a positive electrode mixture paste for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery.
  • a non-aqueous electrolyte secondary battery can be cited, and a lithium ion secondary battery can be cited as a typical non-aqueous electrolyte secondary battery.
  • a lithium ion secondary battery is composed of a negative electrode, a positive electrode, an electrolyte, and the like, and an active material for the negative electrode and the positive electrode is made of a material that can desorb and insert lithium.
  • Lithium ion secondary batteries are currently being actively researched and developed. Among them, lithium ion secondary batteries using a layered or spinel type lithium metal composite oxide as a positive electrode material have a high 4V class. Since a voltage can be obtained, the practical application is progressing as a battery having a high energy density.
  • lithium cobalt composite oxide LiCoO 2
  • lithium metal composite oxide LiNiO 2
  • lithium nickel cobalt manganese composite oxide LiNi 1/3 Co 1/3 Mn 1/3 O 2
  • lithium manganese composite oxide LiMn 2 O 4
  • it is effective to contain lithium in excess of the stoichiometric composition with respect to metal elements such as nickel, cobalt, and manganese.
  • the positive electrode of the nonaqueous electrolyte secondary battery is, for example, a positive electrode obtained by mixing a positive electrode active material, a binder such as polyvinylidene fluoride (PVDF), and a solvent such as normal methyl-2-pyrrolidone (NMP). It is formed by applying a composite paste to a current collector such as an aluminum foil. At this time, lithium liberated from the positive electrode active material in the positive electrode mixture paste may react with moisture contained in the binder to generate lithium hydroxide. The generated lithium hydroxide and the binder may react to cause gelation of the positive electrode mixture paste. Gelation of the positive electrode mixture paste causes poor operability and yield. This tendency becomes remarkable when the lithium in the positive electrode active material is in excess of the stoichiometric ratio and the ratio of nickel is high.
  • PVDF polyvinylidene fluoride
  • NMP normal methyl-2-pyrrolidone
  • Patent Document 1 discloses Li x Ni 1-y A y O 2 (0.98 ⁇ x ⁇ 1.06, 0.05 ⁇ y ⁇ 0.30, A is at least one of Co and Al).
  • the positive electrode active material for a non-aqueous electrolyte secondary battery in which 5 g is stirred and mixed in 100 g of pure water for 120 minutes and then left to stand for 30 seconds, and the pH of the supernatant is 12.7 or less at 25 ° C. has been proposed. It is described that this positive electrode active material has fluidity and excellent gelation resistance even after 24 hours have passed since the slurry (positive electrode mixture paste) was produced.
  • Patent Document 2 proposes a positive electrode composition for a non-aqueous electrolyte secondary battery including a positive electrode active material composed of a lithium transition metal composite oxide and additive particles composed of particles composed of acidic oxide particles. Yes.
  • a positive electrode active material composed of a lithium transition metal composite oxide
  • additive particles composed of particles composed of acidic oxide particles.
  • lithium hydroxide generated by reacting with moisture contained in the binder preferentially reacts with the acidic oxide, suppressing the reaction between the generated lithium hydroxide and the binder, It is described that gelation is suppressed.
  • the acidic oxide plays a role as a conductive agent in the positive electrode, lowers the resistance of the whole positive electrode, and contributes to the improvement of the output characteristics of the battery.
  • Patent Document 3 also provides a lithium transition metal oxide containing LiOH outside the composition as the positive electrode active material; grasping the molar amount P of LiOH contained per gram of the positive electrode active material; Prepare 0.05 mol or more of tungsten oxide in terms of tungsten atom per mol of LiOH with respect to the amount P; and knead the positive electrode active material and tungsten oxide together with the conductive material and the binder in an organic solvent.
  • a method for producing a lithium ion secondary battery has been proposed.
  • the positive electrode active material is excellent in output characteristics and charge / discharge cycle characteristics by being composed of particles having a small particle size and a narrow particle size distribution. This is because particles having a small particle size have a large specific surface area, and when used as a positive electrode active material, a sufficient reaction area with the electrolytic solution can be secured, and the positive electrode is made thin, This is because the movement distance between the positive electrode and the negative electrode can be shortened, so that the positive electrode resistance can be reduced.
  • the particles having a narrow particle size distribution can equalize the voltage applied to the particles in the electrode, and therefore it is possible to suppress a decrease in battery capacity due to the selective deterioration of the fine particles.
  • the positive electrode active material In order to further improve the output characteristics and charge / discharge cycle characteristics, for example, it has been reported that it is effective to make the positive electrode active material have a hollow structure. Since such a positive electrode active material can increase the reaction area with the electrolyte compared to a solid positive electrode active material having the same particle size, the positive electrode resistance can be greatly reduced. .
  • transition metal composite hydroxide particles serving as a precursor of a positive electrode active material are mainly divided into two stages: a nucleation process for mainly nucleation and a particle growth process for mainly particle growth.
  • a method for producing by a crystallized reaction clearly separated.
  • the pH value of the aqueous reaction solution is adjusted to a particle temperature within a range of 12 or more (for example, 12.0 to 13.4 or 12.0 to 14.0) in the nucleation step, based on a liquid temperature of 25 ° C. In the process, it is controlled to be lower than the nucleation process and 12 or less (for example, 10.5 to 12.0).
  • the reaction atmosphere is an oxidizing atmosphere at the initial stage of the nucleation step and the particle growth step, and is switched to a non-oxidizing atmosphere at a predetermined timing.
  • the obtained transition metal composite hydroxide particles have a small particle size, a narrow particle size distribution, a low-density central portion composed of fine primary particles, and a high density composed of plate-like or needle-like primary particles. And the outer shell. Therefore, when such transition metal composite hydroxide particles are fired, the low density center portion is greatly contracted, and a space portion is formed inside.
  • the particle properties of the composite hydroxide particles are inherited by the positive electrode active material. It is said that secondary batteries using these positive electrode active materials can improve capacity characteristics, output characteristics, and charge / discharge cycle characteristics.
  • Patent Document 6 discloses an alkaline solution in which a tungsten compound is dissolved in a lithium metal composite oxide powder composed of primary particles and secondary particles formed by aggregation of the primary particles. Adding and mixing the first step of dispersing W on the surface of the lithium metal composite oxide powder or the primary particles of the powder, the alkali solution in which the mixed tungsten compound is dissolved, and the lithium metal composite A positive electrode for a non-aqueous electrolyte secondary battery comprising a second step of forming fine particles containing W and Li on the surface of the lithium metal composite oxide powder or the surface of primary particles of the powder by heat-treating the oxide powder. A method for producing an active material has been proposed.
  • the proposal of the above-mentioned Patent Document 1 merely provides a condition that allows a positive electrode active material for a lithium secondary battery that is stable for a long time in a slurry (positive electrode mixture paste) to be practically determined. It is insufficient as a measure for suppressing gelation of the composite paste. Moreover, in the proposal of the above-mentioned patent document 2, there is a fear that the separator is damaged and the safety is lowered due to the remaining acidic oxide particles. Moreover, it cannot be said that gelation suppression is sufficient. Further, even in the proposal of the above-mentioned Patent Document 3, it cannot be said that the problem regarding the breakage of the separator due to the remaining acidic oxide (for example, tungsten oxide) and the suppression of gelation are not solved.
  • the remaining acidic oxide for example, tungsten oxide
  • Patent Document 4 and Patent Document 5 above when the reaction area with the electrolyte is increased in order to improve output characteristics and charge / discharge cycle characteristics, gelation of the positive electrode mixture paste is promoted. New problems may arise. Furthermore, in the proposal of the above-mentioned Patent Document 6, although the output characteristics have been studied, no study has been made on the gelation suppression of the positive electrode mixture paste. Therefore, although some of the above proposals have been examined with regard to the suppression of gelation of the positive electrode mixture paste and the improvement of battery characteristics, it cannot be said that the problem has been sufficiently solved.
  • the present invention improves the stability of the positive electrode mixture paste when producing a non-aqueous electrolyte secondary battery, and satisfies the output characteristics and cycle characteristics when the secondary battery is configured. It aims at providing the positive electrode active material for nonaqueous electrolyte secondary batteries which can improve discharge capacity simultaneously, and its manufacturing method. Another object of the present invention is to provide a positive electrode mixture paste using such a positive electrode active material and a non-aqueous electrolyte secondary battery.
  • the present inventor has intensively studied on the gelation suppression and output characteristics of the positive electrode mixture paste for the non-aqueous electrolyte secondary battery.
  • the present inventors used the positive electrode mixture paste as a positive electrode active material.
  • the lithium metal composite oxide is greatly influenced by the pH of the lithium metal composite oxide and the form of the compound in which excess lithium is formed on the surface of the lithium metal composite oxide particles. It was found that the pH can be controlled and the reaction resistance of the positive electrode active material can be reduced to improve the output characteristics.
  • the present invention was completed by obtaining the knowledge that the form of the compound formed by excess lithium can be controlled by mixing and drying water in the lithium metal composite oxide.
  • the method comprises mixing a fired powder made of a lithium metal composite oxide having a layered crystal structure and water, and drying the mixture obtained by the mixing.
  • baking powder formula (1): Li s Ni 1 -x-y-z Co x Mn y M 1 z O 2 ( however, 0.05 ⁇ x ⁇ 0.35,0 ⁇ y ⁇ 0.35 , 0 ⁇ z ⁇ 0.10, 0.95 ⁇ s ⁇ 1.50
  • M 1 is represented by at least one element selected from V, Mg, Mo, Nb, Ti, W and Al), and primary
  • the secondary particles formed by agglomeration of the particles contain water, and 5 g of the obtained positive electrode active material is dispersed in 100 ml of pure water, and the pH at 25 ° C. when measuring the supernatant after standing for 10 minutes is 25 ° C.
  • the water when mixing the calcined powder and water, it is preferable to add the water by spraying it to a droplet size of 1 to 2000 ⁇ m. Moreover, it is preferable to mix water in the range of 1 mass% or more and 35 mass% or less with respect to baked powder. Moreover, it is preferable to mix water in the range of 0.003 g / m 2 or more and 0.025 g / m 2 or less with respect to the surface area of the fired powder. Moreover, it is preferable to mix water in 1 mass% or more and 6 mass% or less with respect to baked powder.
  • the fired powder preferably has an average particle size in the range of 3 ⁇ m to 15 ⁇ m, and [(d90 ⁇ d10) / average particle size], which is an index indicating the spread of the particle size distribution, is 0.7 or less.
  • gap measured by cross-sectional observation occupies is 4.5% or more and 60% or less with respect to the whole cross-sectional area of baked powder.
  • the firing powder has the general formula (2): Li s Ni 1 -x-y-z-t Co x Mn y M 2 z W t O 2 ( however, 0.05 ⁇ x ⁇ 0.35,0 ⁇ y ⁇ 0.35, 0 ⁇ z ⁇ 0.10, 0.95 ⁇ s ⁇ 1.50, 0.0001 ⁇ t ⁇ 0.03, 0.0001 ⁇ z + t ⁇ 0.10, M 2 is V, It is preferably represented by at least one element selected from Mg, Mo, Nb, Ti and Al.
  • a positive electrode active material for a non-aqueous electrolyte secondary battery comprising a lithium metal composite oxide powder having a layered crystal structure, wherein the lithium metal composite oxide powder has the general formula Li s.
  • M 1 is represented by at least one element selected from V, Mg, Mo, Nb, Ti, W and Al), and includes secondary particles formed by aggregation of primary particles
  • 5 g of the positive electrode active material is dispersed in 100 ml of pure water, and the pH at 25 ° C.
  • the positive electrode active material for a non-aqueous electrolyte secondary battery is provided.
  • the positive electrode active material preferably has a ratio of the amount of excess LiOH to excess Li 2 CO 3 of 0.3 or less. Further, the ratio of the amount of surplus LiOH and surplus Li 2 CO 3 is 0.18 or more, and the amount of surplus Li 2 CO 3 is 0.157 ⁇ 10 ⁇ 2 g / m 2 with respect to the surface area of the positive electrode active material. The following is preferable.
  • the positive electrode active material has an average particle size in the range of 3 ⁇ m or more and 15 ⁇ m or less, and [(d90 ⁇ d10) / average particle size], which is an index indicating the spread of the particle size distribution, is 0.7 or less. preferable.
  • gap which is measured in the cross-sectional observation of lithium metal complex oxide powder occupies 4.5% or more and 60% or less with respect to the cross-sectional area of this lithium metal complex oxide particle whole.
  • the lithium metal composite oxide powder represented by the general formula Li s Ni 1-x-y -z-t Co x Mn y M 2 z W t O 2 ( however, 0.05 ⁇ x ⁇ 0.35,0 ⁇ y ⁇ 0.35, 0 ⁇ z ⁇ 0.10, 0.95 ⁇ ⁇ s ⁇ 1.50, 0.0001 ⁇ t ⁇ 0.03, 0.0001 ⁇ z + t ⁇ 0.10, M 2 is V And at least one element selected from Mg, Mo, Nb, Ti and Al.
  • the positive electrode mixture paste for a non-aqueous electrolyte secondary battery includes the positive electrode active material for a non-aqueous electrolyte secondary battery.
  • a non-aqueous electrolyte secondary battery has a positive electrode containing the positive electrode active material for a non-aqueous electrolyte secondary battery.
  • a positive electrode mixture slurry with high gel stability and high stability is obtained, and excellent output characteristics and cycle characteristics when used for a positive electrode material of a battery, and excellent charge / discharge capacity, It is possible to provide a positive electrode active material for a non-aqueous electrolyte secondary battery. Furthermore, the manufacturing method is easy and suitable for production on an industrial scale, and its industrial value is extremely large.
  • FIG. 1 is a figure showing an example of a manufacturing method of a cathode active material for nonaqueous system electrolyte rechargeable batteries of an embodiment.
  • FIG. 2 is a schematic explanatory diagram of an impedance evaluation measurement example and an equivalent circuit used for analysis.
  • FIG. 3 is a schematic cross-sectional view of a coin-type battery used for battery evaluation.
  • FIG. 4 is a schematic explanatory diagram of a laminate cell used for battery evaluation.
  • FIG. 5 is an example of a measurement result of ⁇ V by the current pause method used for low-temperature output evaluation.
  • Positive electrode active material for non-aqueous electrolyte secondary battery The non-aqueous electrolyte positive electrode active material of the present embodiment (hereinafter also referred to as “positive electrode active material”) is a lithium metal composite oxide powder having a layered crystal structure.
  • the lithium metal composite oxide powder has the general formula (1): Li s Ni 1-xyZ Co x Mn y M 1 z O 2 ( However, 0.05 ⁇ x ⁇ 0.35, 0 ⁇ y ⁇ 0.35, 0 ⁇ z ⁇ 0.10, 0.95 ⁇ s ⁇ 1.50, M 1 is V, Mg, Mo, Nb, And at least one element selected from Ti, W, and Al), and includes secondary particles formed by aggregation of primary particles. Further, 5 g of the positive electrode active material is dispersed in 100 ml of pure water, and the pH at 25 ° C. when measuring the supernatant after standing for 10 minutes is 11 to 11.9, and excess LiOH determined by titration And the mass of surplus Li 2 CO 3 (surplus LiOH / surplus Li 2 CO 3 ) is 0.45 or less.
  • s represents the atomic ratio of Li to the total of Ni, Co, Mn and M 1 in the lithium metal composite oxide powder (Li / Me), and production of the lithium metal composite oxide powder The amount of Li added in the process is reflected.
  • s satisfies 0.95 ⁇ s ⁇ 1.50, and preferably satisfies 1.00 ⁇ s ⁇ 1.30.
  • the amount of Li is in the range of s, the battery capacity and output characteristics of the lithium metal composite oxide itself can be improved.
  • Composite oxide powder obtained by a normal production method (for example, lithium nickel composite oxide powder obtained by firing nickel composite hydroxide or nickel composite oxide and lithium compound) is a secondary particle.
  • unreacted lithium compounds (surplus lithium compounds) exist on the surfaces of the primary particles.
  • the surplus lithium compound may elute in the positive electrode mixture paste (hereinafter also referred to as “paste”) to raise the pH and cause the paste to gel. It is also conceivable that excess lithium is present inside the lithium metal composite oxide powder and is eluted into the paste to cause the paste to gel.
  • the present inventors consider that it is important to suppress elution of excess lithium into the paste, and unreacted particles present on the surfaces of secondary particles and primary particles. We focused on the form of the lithium compound.
  • surplus lithium compound existing on the surfaces of the secondary particles and the primary particles examples include unreacted LiOH (surplus LiOH) and unreacted Li 2 CO 3 (surplus Li 2 CO 3 ).
  • Recess LiOH easily elutes into the paste and raises the pH of the paste to promote gelation.
  • excessive lithium (Li) in the composite oxide powder may elute into the paste to form LiOH and raise the pH of the paste to cause gelation.
  • surplus LiOH refers to a lithium source that can be in the form of LiOH during paste preparation, and includes secondary particles, unreacted LiOH on the surface of the primary particles, excess lithium inside the composite oxide powder, and the like.
  • surplus Li 2 CO 3 is less likely to elute into the paste than LiOH and has a small effect of gelling the paste.
  • the present inventors convert surplus LiOH into Li 2 CO 3 and immobilize it as surplus Li 2 CO 3 , thereby reducing elution of LiOH into the paste and suppressing paste gelation.
  • the present invention has been completed on the basis of a novel idea that it may be possible. That is, the positive electrode active material of this embodiment has a mass ratio (LiOH / Li 2 CO 3 ) of surplus LiOH and surplus Li 2 CO 3 determined by a titration method of 0.45 or less, preferably 0.3. It is as follows.
  • reaction resistance of the positive electrode active material (hereinafter referred to as “positive electrode resistance”) ) Can be brought into a lower state, exhibiting better output and cycle characteristics and higher initial charge / discharge capacity.
  • the positive electrode active material of the present embodiment exhibits excellent characteristics not only at room temperature but also at a low temperature (eg, ⁇ 20 ° C.).
  • the lower limit of LiOH / Li 2 CO 3 is preferably 0.10 or more, and more preferably 0.18 or more.
  • the surface of the primary particle means not only the surface of the primary particle exposed on the outer surface of the secondary particle, but also the space near and inside the surface of the secondary particle through which the electrolyte can penetrate through the outside of the secondary particle. It also includes the surface of the primary particles exposed to the surface. Furthermore, even if it is a grain boundary between primary particles, if the primary particle bonding is incomplete and the electrolyte solution can permeate, it is included in the primary particle surface.
  • excess LiOH present on the surface of the primary particles inhibits Li movement between the complex oxide crystal and the electrolytic solution. Therefore, by converting excess LiOH to excess Li 2 CO 3 and immobilizing it on the primary particle surface, by reducing the amount of excess LiOH, excess LiOH present on the primary surface or secondary particle surface is removed, and Li Is not hindered, and the charge / discharge capacity (hereinafter also referred to as “battery capacity”) when used in a battery can be improved.
  • excess LiOH present on the primary particle surface is fixed as excess Li 2 CO 3 , it is once removed from the primary particle surface and eluted in the added water, and then as excess Li 2 CO 3 as the primary Li 2 CO 3. It is thought that it aggregates on the particle surface. Therefore, the area of the surplus lithium compound (including surplus LiOH and surplus Li 2 CO 3 ) that covers the primary particle surface is reduced, the contact surface between the electrolyte and the primary particle surface is secured, and the movement of Li is promoted. Therefore, the positive electrode resistance is reduced, and further, the internal resistance of the secondary battery is reduced.
  • the positive electrode active material of the present embodiment exhibits excellent characteristics not only at room temperature but also at a low temperature (eg, ⁇ 20 ° C.). Further, since the voltage applied to the load side is increased, the insertion and extraction of lithium at the positive electrode is sufficiently performed, so that the battery capacity and cycle characteristics are improved. Furthermore, since the movement of Li becomes easy and the load received by the positive electrode active material during charge / discharge is reduced, the charge / discharge cycle characteristics are also excellent.
  • the amount of excess LiOH in the positive electrode active material is preferably 0.15% by mass or less, and more preferably 0.12% by mass or less with respect to the entire positive electrode active material.
  • the lower limit of the amount of excess LiOH is preferably 0.05% by mass or more with respect to the total amount of the positive electrode active material, from the viewpoint of suppressing deterioration of battery characteristics.
  • the excess LiOH becomes too small, it indicates that excessive lithium is extracted from the crystal of the lithium metal composite oxide particles when the excess LiOH is fixed as Li 2 CO 3 .
  • the amount of excess Li 2 CO 3 in the positive electrode active material is preferably 0.200 ⁇ 10 ⁇ 2 g / m 2 or less with respect to the surface area of the positive electrode active material, preferably 0.157 ⁇ 10 ⁇ 2 g / m 2. It is more preferably 2 or less, and further preferably 0.155 ⁇ 10 ⁇ 2 g / m 2 or less.
  • the lower limit of the amount of excess Li 2 CO 3 with respect to the surface area of the positive electrode active material is not particularly limited, and is, for example, 0.100 ⁇ 10 ⁇ 2 g / m 2 or more.
  • the positive electrode active material of this embodiment has a pH of 11 or more and 11.9 or less at 25 ° C. when 5 g of the positive electrode active material is dispersed in 100 ml of pure water and the supernatant is measured after standing for 10 minutes. The degree of elution of the lithium into the paste is evaluated by dispersing 5 g of the positive electrode active material in 100 ml of pure water and measuring the pH of the supernatant after standing for 10 minutes.
  • the pH of the supernatant liquid at 25 ° C. (hereinafter, also simply referred to as “pH value of the positive electrode active material”) is controlled in the range of 11 or more and 11.9 or less, so that the paste becomes very gelled. To be suppressed.
  • pH value of the positive electrode active material When the pH is less than 11, a large amount of excess Li 2 CO 3 is formed, and when lithium is extracted from the lithium metal composite oxide more than necessary, it is charged and discharged when used for the positive electrode of the battery. The capacity may decrease and the reaction resistance of the positive electrode may increase.
  • the lower limit of the pH value of the positive electrode active material is preferably 11.5 or more.
  • the upper limit of the pH value of the positive electrode active material is preferably 11.8 or less.
  • the lithium metal composite oxide particles include secondary particles composed of aggregated primary particles. Further, the positive electrode active material may include primary particles present alone.
  • the composite oxide particles can form lithium tungstate (LW compound) described later on the primary particle surfaces. Thereby, it is possible to improve the output characteristics while maintaining the charge / discharge capacity, and to obtain better cycle characteristics.
  • t represents the amount of tungsten (W) added to the lithium metal composite oxide.
  • W is 0.0001 ⁇ t ⁇ 0.03, preferably 0.0003 ⁇ t ⁇ 0.02, and more preferably 0.0003 ⁇ t ⁇ 0.012. .
  • W is included in the above range t, in addition to improving the battery capacity and output characteristics of the lithium metal composite oxide itself, excess LiOH is converted to Li 2 CO 3 and immobilized on the surface of the primary particles. In this case, W eluted in the added water reacts with excess lithium eluted in the water, and lithium tungstate is formed, so that the positive electrode resistance can be reduced.
  • s represents the atomic ratio of Li to the total of Ni, Co, Mn, M 2 and W (Li / Me) in the lithium metal composite oxide powder, and the lithium metal composite oxide powder This reflects the amount of Li added in the manufacturing process.
  • S in the general formula (2) is preferably in the same range as s in the general formula (1).
  • the powder characteristics and particle structure of the positive electrode active material can also be selected from known lithium metal composite oxides according to the characteristics required for the battery.
  • the average particle diameter of the positive electrode active material is in the range of 3 ⁇ m or more and 15 ⁇ m or less, and [(d90 ⁇ d10) / average particle diameter], which is an index indicating the spread of the particle size distribution, is preferably 0.7 or less.
  • filling property can be improved and the battery capacity per volume of a battery can be made higher.
  • the applied voltage between the lithium metal composite oxide particles can be made uniform, the load between the particles can be made uniform, and the cycle characteristics can be further improved.
  • the d10 means a particle size in which the number of particles in each particle size is accumulated from the smaller particle size side and the accumulated volume becomes 10% of the total volume of all particles.
  • D90 means a particle diameter in which the number of particles is similarly accumulated and the accumulated volume is 90% of the total volume of all particles.
  • the average particle diameter, d10 and d90 can be obtained from the volume integrated value measured with a laser light diffraction / scattering particle size analyzer.
  • the average particle diameter Mv can be used as the average particle diameter, and can be determined using a laser light diffraction / scattering particle size analyzer in the same manner as d10 and d90.
  • the area ratio (porosity) occupied by the voids measured in the cross-sectional observation of the composite oxide powder is preferably 4.5% or more and 60% or less of the entire cross-sectional area of the secondary particles.
  • the porosity is in the above range, the positive electrode resistance reduction effect can be further increased while suppressing gelation of the paste.
  • the porosity is less than 4.5% of the entire cross-sectional area, a higher reduction effect of the positive electrode resistance may not be obtained.
  • the porosity exceeds 60%, the packing density may decrease, and the battery capacity per battery volume may not be sufficiently obtained.
  • the whole cross-sectional area of a secondary particle is a cross-sectional area including the space
  • the porosity can be measured by observing an arbitrary cross section of the secondary particles using a scanning electron microscope and analyzing the image. Specifically, a plurality of composite oxide particles are embedded in a resin, a cross-section polisher is used to prepare a cross-section sample, and the secondary electron cross-section can be observed with a scanning electron microscope, followed by image analysis. With software (for example, WinRoof 6.1.1 etc.), the void part in the secondary particle is detected in black for any 20 or more secondary particles, and the dense part in the contour of the secondary particle Is detected in white, the total area of the black part and the white part of the 20 or more secondary particles is measured, and the porosity is calculated by calculating the area ratio of [black part / (black part + white part)]. It can be calculated.
  • the specific surface area of the positive electrode active material is preferably 1 m 2 / g or more and 50 m 2 / g or less. When the specific surface area is less than 1 m 2 / g, there is little contact with the electrolytic solution, and high output characteristics may not be obtained. Moreover, when a specific surface area exceeds 50 m ⁇ 2 > / g, contact with electrolyte solution increases too much and suppression of gelatinization may not be enough.
  • the specific surface area can be determined by the BET method using nitrogen gas adsorption.
  • the moisture content of the positive electrode active material is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less.
  • the moisture content of the positive electrode active material is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less.
  • the method for producing the positive electrode active material comprises mixing a fired powder made of a lithium metal composite oxide having a layered crystal structure and water (Step S1) and drying the mixture obtained by the mixing (Step S2).
  • Step S1 a fired powder made of a lithium metal composite oxide having a layered crystal structure and water
  • Step S2 drying the mixture obtained by the mixing
  • FIG. 1 is a view showing an example of a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to the present embodiment (hereinafter also simply referred to as “a method for producing a positive electrode active material”).
  • a method for producing a positive electrode active material hereinafter also simply referred to as “a method for producing a positive electrode active material”.
  • the following description is an example of a manufacturing method, Comprising: It does not limit to this method.
  • a fired powder made of a lithium metal composite oxide having a layered crystal structure and water are mixed (step S1).
  • 5 g of the obtained positive electrode active material was dispersed in 100 ml of pure water, and the pH at 25 ° C. when the supernatant liquid after standing for 10 minutes was measured (hereinafter also simply referred to as “pH value of the positive electrode active material”).
  • pH value of the positive electrode active material Is mixed with an amount of water in the range of 11 to 11.9.
  • step S1 the fired powder and water are mixed so that the positive electrode active material has a pH value in the range of 11 to 11.9.
  • step S2 by mixing a predetermined amount of water, elution of lithium into the paste is suppressed in the paste using the obtained positive electrode active material.
  • step S2 surplus LiOH eluted in water reacts with carbon dioxide in the atmosphere to convert surplus LiOH in the fired powder into Li 2 CO 3 .
  • the excess LiOH-derived lithium is immobilized on the surface of the primary particles.
  • the lower limit of the pH value of the positive electrode active material is 11.5 or more.
  • the upper limit of the pH value is 11.8 or less.
  • the mixing of the fired powder and water can be performed, for example, by adding water to the fired powder and mixing.
  • the amount of water added can be easily determined by collecting a small amount of the fired powder in advance and conducting a preliminary test to confirm the amount of water added.
  • the pH value of the positive electrode active material can be controlled within the above-described range by the addition amount determined in the preliminary test.
  • the method for adding water is not particularly limited, and water may be added dropwise to the fired powder, or water may be added to the fired powder by spraying.
  • water by spraying the fired powder it is preferable to add water by spraying the fired powder to a droplet size of 1 ⁇ m to 2000 ⁇ m.
  • water by spraying with fine droplets water can be added uniformly by the calcined powder, the reaction between excess LiOH and carbon dioxide in the atmosphere can be made more uniform, and a higher output improvement effect and It becomes possible to obtain the gelation suppressing effect.
  • Various sprays and ultrasonic humidifiers can be used as the water spraying method.
  • the droplet size of water when spraying is preferably 1 ⁇ m or more and 2000 ⁇ m or less, and more preferably 5 ⁇ m or more and 1000 ⁇ m or less.
  • the mixture of the baked powder and water may be mixed after adding the baked powder water, or may be mixed while adding water, but in order to make the addition of water more uniform, water is added. It is more preferable to mix them.
  • the surplus LiOH amount varies depending on the atomic ratio of Li to the total of Ni, Co, Mn, and M (Li / Me) in the sintered powder of lithium metal composite oxide, or the production conditions of the sintered powder.
  • the amount of water added may be an amount that allows the pH value of the positive electrode active material to be controlled within the above range by immobilizing these excess LiOH. Therefore, water may be added in a range where the pH value of the positive electrode active material is 11 or more and 11.9 or less.
  • the amount of water to be mixed in the mixing step (step S1) can be appropriately adjusted according to the powder characteristics and particle structure of the fired powder. It is preferable that Thereby, excess LiOH can be fixed and the elution of lithium can be further reduced. Further, with sufficient amount of water, the lithium metal composite oxide particles can be sufficiently permeated to the surface of primary particles inside the lithium metal composite oxide particles, and the fixation of surplus LiOH can be promoted uniformly between the lithium metal composite oxide particles. Capacity and output characteristics can be further improved.
  • the amount of water mixed is more preferably 1% by mass or more and 6% by mass or less with respect to the fired powder. By optimizing the amount of water to be mixed, it is possible to further prevent lithium from being pulled out excessively while fixing excess LiOH, and to maximize the effect of improving the output characteristics at room temperature and low temperature. Is possible.
  • the surface area of the fired powder may vary depending on the composition of the fired powder and the manufacturing conditions. Accordingly, the surface area of the calcined powder to supply desired amounts of water may vary, it is more preferable to mix the water with 0.003 g / m 2 or more 0.025 g / m 2 or less of the range of the surface area.
  • the calcined powder has the general formula (1): Li s Ni 1-xyz Co x Mn y M 1 z O 2 (where 0.05 ⁇ x ⁇ 0.35, 0 ⁇ y ⁇ 0.35, 0 ⁇ z ⁇ 0.10, 0.95 ⁇ s ⁇ 1.50, M is represented by at least one element selected from V, Mg, Mo, Nb, Ti, W and Al), and the primary particles are Secondary particles formed by aggregation are included. Since the powder characteristics and particle structure of the fired powder are inherited up to the positive electrode active material, the composition, powder characteristics, particle structure and the like of the fired powder can be the same as those of the positive electrode active material described above. Further, the fired powder is selected according to the positive electrode active material to be obtained.
  • t indicating the amount of tungsten (W) is 0.0001 ⁇ t ⁇ 0.03, preferably 0.0003 ⁇ t ⁇ 0.02, and more preferably 0.00.
  • W added to the calcined powder is eluted in the water added in the mixing step and similarly reacts with lithium eluted in the water in the drying step to form lithium tungstate on the surface of the primary particles.
  • Lithium tungstate reduces the positive electrode resistance and further improves the output characteristics.
  • the average particle diameter is in the range of 3 ⁇ m to 15 ⁇ m, and is an index indicating the spread of the particle size distribution [(d90 ⁇ d10) / average particle diameter] is 0. .7 or less can be selected.
  • the lower limit of [(d90 ⁇ d10) / average particle diameter] is not particularly limited, but is about 0.25 or more.
  • gap measured in the cross-sectional observation of baking powder occupies is 4.5% or more and 60% or less of the cross-sectional area of this lithium metal complex oxide particle.
  • An apparatus used for mixing the baked powder and water is not particularly limited, and a known apparatus can be used.
  • the mixing is performed using a mixer such as a shaker mixer, a Laedige mixer, a Julia mixer, or a V blender. It is only necessary that the calcined powder and moisture be sufficiently mixed.
  • step S2 the mixture obtained by mixing is dried (step S2).
  • This step dries the mixture of water and calcined powder, and removes excess LiOH (including excess lithium in the lithium metal composite oxide particles) dissolved in water in the mixture on the surface of the primary particles.
  • surplus LiOH reacts with carbon dioxide gas (CO 2 ) in the atmosphere to become Li 2 CO 3 and is immobilized on the primary particle surface as surplus Li 2 CO 3 .
  • the surplus LiOH changes from a thin and widely distributed state on the primary particle surface to a state where surplus Li 2 CO 3 forms fine aggregates and is scattered, the primary particle surface and the electrolyte solution are changed. And the reaction field of Li ion intercalation reaction is increased.
  • the removal of excess LiOH due to the dispersion of excess Li 2 CO 3 is confirmed by an increase in the specific surface area of the lithium metal composite oxide particles.
  • the drying temperature is preferably 450 ° C. or lower. When it exceeds 450 ° C., lithium may further be liberated from the crystal of the lithium metal composite oxide, and the gelation of the paste may not be sufficiently suppressed. From the viewpoint of drying more sufficiently and preventing the liberation of lithium from the lithium metal composite oxide, the drying temperature is more preferably 100 ° C. or higher and 300 ° C. or lower.
  • the drying time is not particularly limited, but can be 1 hour or more and 24 hours or less.
  • the atmosphere during drying is decarboxylated air in which the content of carbon dioxide gas is controlled as necessary in order to avoid excessive reaction of moisture in the atmosphere and carbon and lithium on the surface of the lithium metal composite oxide particles, An inert gas or a vacuum atmosphere can be used, but an air atmosphere is preferable.
  • the content of carbon dioxide gas is preferably 100 ppm to 500 ppm by volume.
  • the pressure of the atmosphere during drying is preferably 1 atm or less. When the atmospheric pressure is higher than 1 atm, the water content of the positive electrode active material may not be sufficiently lowered.
  • the pressure of the atmosphere at the time of drying is a reduced pressure atmosphere (for example, about ⁇ 90 kPa), the moisture content of the positive electrode active material can be further reduced, and the positive electrode resistance of the obtained secondary battery can be reduced.
  • Positive electrode mixture paste for non-aqueous electrolyte secondary battery In the positive electrode mixture paste of this embodiment, elution of lithium from the positive electrode active material is reduced, and gelation of the paste is suppressed. Therefore, the positive electrode mixture paste has a high stability with little change in the viscosity of the paste even after long-term storage. By producing a positive electrode using such a paste, the positive electrode also has stable and excellent characteristics, and the characteristics of the finally obtained battery can be made stable and high.
  • the positive electrode mixture paste is characterized by containing the positive electrode active material, and the other constituent materials are the same as those of a normal positive electrode mixture paste.
  • the content of the positive electrode active material is 60 to 95 parts by mass in the same manner as the positive electrode of a general non-aqueous electrolyte secondary battery, It is preferable that the content of the conductive agent is 1 to 20 parts by mass and the content of the binder is 1 to 20 parts by mass.
  • the conductive agent for example, graphite (natural graphite, artificial graphite, expanded graphite, etc.), carbon black materials such as acetylene black, ketjen black, and the like can be used.
  • the binder plays a role of anchoring the active material particles.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • fluorine rubber ethylene propylene diene rubber
  • styrene butadiene cellulose resin
  • polyacrylic polyacrylic, and the like.
  • An acid or the like can be used.
  • a positive electrode active material, a conductive agent, and activated carbon are dispersed, and a solvent that dissolves the binder is added to the positive electrode mixture.
  • a solvent that dissolves the binder is added to the positive electrode mixture.
  • an organic solvent such as N-methyl-2-pyrrolidone can be used as the solvent.
  • Activated carbon can be added to the positive electrode mixture in order to increase the electric double layer capacity.
  • a powdered positive electrode active material, a conductive agent, and a binder are mixed, and, if necessary, a target solvent such as activated carbon and viscosity adjustment is added and kneaded to prepare a positive electrode mixture paste.
  • Non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and the like, and includes the same components as those of a general non-aqueous electrolyte secondary battery. .
  • the embodiment described below is merely an example, and the nonaqueous electrolyte secondary battery of the present embodiment can be variously modified based on the knowledge of those skilled in the art based on the embodiment described in the present specification. It can be implemented in an improved form. Further, the use of the nonaqueous electrolyte secondary battery of the present embodiment is not particularly limited.
  • the positive electrode mixture paste is applied to, for example, the surface of a current collector made of aluminum foil and dried to disperse the solvent. If necessary, pressurization may be performed by a roll press or the like to increase the electrode density. In this way, a sheet-like positive electrode can be produced.
  • the sheet-like positive electrode can be cut into an appropriate size or the like according to the target battery and used for battery production.
  • the method for manufacturing the positive electrode is not limited to the illustrated one, and other methods may be used.
  • Negative electrode A negative electrode mixture in which a negative electrode active material capable of occluding and desorbing lithium ions is mixed with a binder and an appropriate solvent is added to the negative electrode. Is applied to the surface of a metal foil current collector such as copper, dried, and compressed to increase the electrode density as necessary.
  • the negative electrode active material for example, natural graphite, artificial graphite, a fired organic compound such as phenol resin, and a powdery carbon material such as coke can be used.
  • a fluorine-containing resin such as PVDF can be used as the negative electrode binder, as in the case of the positive electrode, and a solvent for dispersing these active materials and the binder can be N-methyl-2-pyrrolidone or the like.
  • Organic solvents can be used.
  • (C) Separator A separator is interposed between the positive electrode and the negative electrode.
  • the separator separates the positive electrode and the negative electrode and retains the electrolyte, and a thin film such as polyethylene or polypropylene and a film having many minute holes can be used.
  • Non-aqueous electrolyte The non-aqueous electrolyte is obtained by dissolving a lithium salt as a supporting salt in an organic solvent.
  • the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and trifluoropropylene carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate, and dipropyl carbonate, tetrahydrofuran, 2- One kind selected from ether compounds such as methyltetrahydrofuran and dimethoxyethane, sulfur compounds such as ethylmethylsulfone and butanesultone, phosphorus compounds such as triethyl phosphate and trioctyl phosphate, etc. are used alone or in admixture of two or more. be able to.
  • the non-aqueous electrolyte solution may contain a radical scavenger, a surfactant, a flame retardant, and the like.
  • the shape of the non-aqueous electrolyte secondary battery of the present embodiment constituted by the positive electrode, the negative electrode, the separator and the non-aqueous electrolyte described above is a cylindrical type, a laminated type, etc. It can be various.
  • the positive electrode and the negative electrode are laminated via a separator to form an electrode body, and the obtained electrode body is impregnated with a non-aqueous electrolyte and communicated with the positive electrode current collector and the outside.
  • the positive electrode terminal and the negative electrode current collector and the negative electrode terminal communicating with the outside are connected using a current collecting lead or the like and sealed in a battery case to complete a non-aqueous electrolyte secondary battery. .
  • the nonaqueous electrolyte secondary battery using the positive electrode active material of the present embodiment has a high capacity and a high output.
  • the non-aqueous electrolyte secondary battery using the positive electrode active material according to the present embodiment obtained in a more preferable form has a high value of 150 mAh / g or more when used for the positive electrode of the 2032 type coin battery described in the examples. An initial discharge capacity and a low positive electrode resistance are obtained.
  • the battery reaction at the electrode consists of a resistance component accompanying the charge transfer and a capacity component due to the electric double layer. When these are expressed as an electric circuit, it becomes a parallel circuit of resistance and capacity. It is represented by an equivalent circuit in which circuits are connected in series. Fitting calculation is performed on the Nyquist diagram measured using this equivalent circuit, and each resistance component and capacitance component can be estimated.
  • the positive electrode resistance is equal to the diameter of the semicircle on the low frequency side of the obtained Nyquist diagram.
  • the positive electrode resistance can be estimated by performing AC impedance measurement on the manufactured positive electrode and performing fitting calculation with the equivalent circuit on the obtained Nyquist diagram.
  • the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
  • the performance (stability of paste, initial discharge capacity, positive electrode resistance, internal resistance, discharge)
  • the capacity retention ratio was evaluated by the following method.
  • a negative electrode sheet in which a graphite powder punched into a disk shape with a diameter of 14 mm and an average particle diameter of about 20 ⁇ m and polyvinylidene fluoride are applied to a copper foil is used, and 1 M LiPF 6 is used as the electrolyte for the electrolyte.
  • An equivalent mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) (manufactured by Toyama Pharmaceutical Co., Ltd.) was used.
  • As the separator 3 a polyethylene porous film having a film thickness of 25 ⁇ m was used.
  • the coin-type battery B has a gasket 4 and a wave washer 5, and the positive electrode can 6 and the negative electrode can 7 are assembled into a coin-shaped battery.
  • the initial discharge capacity, the positive electrode resistance, and the cycle characteristics showing the performance of the manufactured coin battery B were evaluated as follows.
  • the initial discharge capacity is left for about 24 hours after the coin-type battery B is manufactured, and after the open circuit voltage OCV (Open Circuit Voltage) is stabilized, the current density with respect to the positive electrode is set to 0.1 mA / cm 2 and the cut-off voltage 4
  • OCV Open Circuit Voltage
  • the positive electrode resistance is obtained by charging the coin-type battery B at 25 ° C. with a charging potential of 4.1 V and measuring the positive electrode resistance by the AC impedance method using a frequency response analyzer and a potentiogalvanostat (manufactured by Solartron, 1255B).
  • the Nyquist plot shown in FIG. Since this Nyquist plot is represented as the sum of the solution resistance, the negative electrode resistance and its capacity, and the characteristic curve indicating the positive electrode resistance and its capacity, the fitting calculation was performed using an equivalent circuit based on this Nyquist plot, and the positive resistance The value of was calculated.
  • cycle characteristics discharge capacity maintenance rate
  • discharge capacity maintenance rate discharge capacity maintenance rate
  • the evaluation of the cycle characteristics was performed based on the capacity maintenance rate after the cycle test.
  • the cycle test was held at 60 ° C. and paused for 10 minutes after the initial discharge capacity measurement, and the charge / discharge cycle was repeated 500 cycles (charge / discharge) including the initial discharge capacity measurement in the same manner as the initial discharge capacity measurement.
  • the discharge capacity at the 500th cycle was measured, and the percentage of the discharge capacity at the 500th cycle with respect to the discharge capacity at the first cycle (initial discharge capacity) was determined as the capacity retention rate (%).
  • a laminate cell C used for evaluation was produced as follows. After mixing a positive electrode active material, a conductive material (acetylene black), and a binder (PVDF) at a mass ratio of 85: 10: 5 to an aluminum current collector foil (thickness 0.02 mm), a solvent (NMP) was added.
  • a solvent NMP
  • the positive electrode active material was made into a paste, applied while leaving a conductive part connected to the outside, and dried to prepare a positive electrode sheet 8 on which a positive electrode active material layer having a basis weight of 7 mg / cm 2 was formed.
  • carbon powder acetylene black
  • a negative electrode sheet 9 was produced.
  • a laminated sheet was formed between the produced positive electrode sheet 8 and negative electrode sheet 9 with a separator 10 made of a polypropylene microporous film (thickness 20.7 ⁇ m, porosity density 43.9%) interposed therebetween. Then, the laminated sheet is sandwiched between two aluminum laminate sheets 11 (thickness 0.55 mm), and the three sides of the aluminum laminate sheet 11 are heat-sealed to form a heat-sealed portion HS, which is sealed. 4 was assembled. Thereafter, 260 ⁇ l of an electrolyte made by Ube Industries, Ltd.
  • the difference in ⁇ V can be interpreted as a resistance difference as it is, that is, the smaller the ⁇ V, the lower the resistance, so the value of ⁇ V was evaluated as a direct current resistance under low temperature conditions.
  • An example of the measurement result of the current pause method is shown in FIG.
  • the obtained paste was stored for 76 hours, and the viscosity ratio before and after storage (paste viscosity after storage for 76 hours / paste viscosity immediately after preparation) was evaluated.
  • the viscosity was measured with a vibration viscometer (VM10A manufactured by Seconic).
  • the excess lithium amount was evaluated by titrating Li eluted from the positive electrode active material. After adding 10 ml of pure water to 1 g of the obtained positive electrode active material and stirring for 1 minute, the lithium elution from the neutralization point appearing by adding 1 mol / liter hydrochloric acid while measuring the pH of the filtered filtrate was performed. The compound state was analyzed to evaluate the excess lithium amount.
  • the first neutralization point (shoulder) from the high alkali side indicates the LiOH amount
  • the second neutralization point indicates the Li 2 CO 3 amount.
  • Example 1 Lithium metal composite represented by Li 1.20 Ni 0.35 Co 0.35 Mn 0.30 O 2 obtained by a known technique of mixing and baking oxide powder containing Ni as a main component and lithium hydroxide Baked oxide powder (average particle size: 5.07 ⁇ m, [(d90-d10) / average particle size]: 0.42, porosity: 14.2%: specific surface area 2.50 g / m 2 ) It was. Water was added to the calcined powder used as a base material in an amount of 1.5% by mass with respect to the calcined powder, and further mixed. Then, the positive electrode active material was obtained by drying at 150 degreeC for 12 hours in an atmospheric condition. The production conditions of the positive electrode active material and the following measurement / evaluation results are shown in Tables 1 and 2.
  • the specific surface area of the positive electrode active material was determined by a BET method using nitrogen gas adsorption.
  • PH measurement 5 g of the obtained positive electrode active material was dispersed in 100 ml of pure water, allowed to stand for 10 minutes, and the pH of the supernatant liquid at 25 ° C. was measured.
  • Prositive electrode paste Using the obtained positive electrode active material, the viscosity of the positive electrode mixture paste produced by the above method was measured.
  • Battery evaluation Using the obtained positive electrode active material, the battery characteristics of the coin-type battery B and the laminate cell C having the positive electrode prepared by the above method were evaluated.
  • Example 2 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the amount of water added was 3% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 3 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the amount of water added was 5% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 4 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the amount of water added was 7% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 5 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the amount of water added was 14% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 6 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the amount of water added was 30% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 7 The fired powder used as a base material is put in a vat, and 3% by mass of water is sprayed on the lithium metal composite oxide powder under the condition that the average droplet diameter is about 300 ⁇ m using a spray bottle.
  • a positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that mixing was performed while adding. The evaluation results are shown in Tables 1 and 2.
  • Example 8 Put the calcined powder as the base material into a Henschel mixer (FM20C / I manufactured by Nippon Coke Co., Ltd.) and stir and mix the calcined powder with stirring blades in the tank so that the average droplet diameter is about 300 ⁇ m. Under the conditions, 3 mass% water is sprayed and added to the lithium metal composite oxide powder using a spray, and then mixed, and then dried at 130 ° C. for 2 hours in a reduced pressure atmosphere of about ⁇ 90 kPa. In the same manner as in Example 1, a positive electrode active material was obtained and evaluated. The evaluation results are shown in Tables 1 and 2.
  • Example 9 A calcined powder of a lithium metal composite oxide having a composition of Li 1.20 (Ni 0.35 Co 0.35 Mn 0.30 ) 0.995 W 0.005 O 2 (average particle size: 4) A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that it was set to .97 ⁇ m, [(d90-d10) / average particle diameter] 0.41, and porosity: 15.6%). The evaluation results are shown in Tables 1 and 2.
  • the above composition of the base material is such that the molar ratio of Ni, Co, and Mn (Ni: Co: Mn) is 0.35: 0.35: 0.30, and the sum of Ni, Co, and Mn, and W
  • the molar ratio (Ni + Co + Mn: W) is 0.995: 0.005
  • the molar ratio (Li: Me) of Li to Me (total of Ni, Co, Mn and W) is 1.20: 1.
  • Example 11 A positive electrode active material was obtained and evaluated in the same manner as in Example 7 except that the amount of water added was 5% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 12 A positive electrode active material was obtained and evaluated in the same manner as in Example 7 except that the amount of water added was 7% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 13 A positive electrode active material was obtained and evaluated in the same manner as in Example 7 except that the amount of water added was 14% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 14 A positive electrode active material was obtained and evaluated in the same manner as in Example 7 except that the amount of water added was 30% by mass. The evaluation results are shown in Tables 1 and 2.
  • Example 15 The fired powder used as a base material is put in a vat, and 3% by mass of water is sprayed on the lithium metal composite oxide powder under the condition that the average droplet diameter is about 300 ⁇ m using a spray bottle.
  • a positive electrode active material was obtained and evaluated in the same manner as in Example 9 except that mixing was performed while adding. The evaluation results are shown in Tables 1 and 2.
  • Example 16 Put the calcined powder as the base material into a Henschel mixer (FM20C / I manufactured by Nippon Coke Co., Ltd.) and stir and mix the calcined powder with stirring blades in the tank so that the average droplet diameter is about 300 ⁇ m.
  • a Henschel mixer FM20C / I manufactured by Nippon Coke Co., Ltd.
  • Example 1 A positive electrode active material was obtained and evaluated in the same manner as in Example 1 except that the base material was directly used as the positive electrode active material. The evaluation results are shown in Tables 1 and 2.
  • Example 2 A positive electrode active material was obtained and evaluated in the same manner as in Example 7 except that the base material was directly used as the positive electrode active material. The evaluation results are shown in Tables 1 and 2.
  • the secondary battery using the positive electrode active material of the example has an initial discharge capacity, a positive electrode resistance, a battery internal resistance, and a capacity maintenance ratio as compared with the secondary battery using the positive electrode active material of the comparative example in which water is not mixed. In either case, good results were obtained.
  • the positive electrode resistance and the battery internal resistance were further reduced. In particular, the internal resistance of the battery showing output characteristics at low temperatures was significantly reduced.
  • Examples 1 to 3, 7, 8, 9 to 11, 15 and 16 in which the amount of water to be mixed was optimized had a lithium extraction amount as compared with Examples 4 to 6 and 12 to 14 having the same composition.
  • the output characteristics are improved as compared with the examples of the same composition while maintaining the low viscosity ratio of the positive electrode mixture paste.
  • the output characteristics of Examples 7, 8, 15, and 16 to which water was added by spraying are further improved.
  • the content of surplus LiOH was reduced while the content of surplus Li 2 CO 3 was increased as compared with Comparative Examples 1 and 2 in which water was not mixed.
  • LiOH / Li 2 CO 3 was 0.45 or less. This is presumably because excess LiOH in the fired powder was converted to Li 2 CO 3 in the step of adding water and subsequent drying.
  • the positive electrode mixture paste using the positive electrode active material of the example has a lower viscosity ratio value and excellent viscosity stability than the positive electrode mixture paste of the comparative example.

Abstract

L'objet de la présente invention est de fournir une matière active d'électrode positive pour une pile secondaire à électrolyte non aqueux avec laquelle il est possible d'améliorer la stabilité d'une pâte de matière d'électrode positive lors de la fabrication d'une pile secondaire à électrolyte non aqueux, et avec laquelle il est possible d'améliorer la capacité et les caractéristiques de sortie de la pile lors de la configuration d'une pile secondaire. Le problème est résolu à l'aide d'un procédé de fabrication d'une matière active d'électrode positive pour une pile secondaire à électrolyte non aqueux, etc. consistant à mélanger de l'eau avec une poudre de cuisson comprenant un oxyde métallique composite de lithium ayant une structure cristalline de structure stratifiée, et à sécher le mélange obtenu par mélange; et pour lequel la poudre de cuisson contient des particules secondaires formées par l'agglomération de particules primaires, et l'eau est mélangée en une quantité telle que lorsque 5 g de la matière active d'électrode positive obtenue sont dispersés dans 100 ml d'eau purifiée, et que le liquide surnageant après repos pendant 10 minutes est mesuré, le pH à 25 °C se situe dans la plage de 11 à 11,9.
PCT/JP2017/011450 2016-03-24 2017-03-22 Matière active d'électrode positive pour pile secondaire à électrolyte non aqueux et son procédé de fabrication, pâte de matière d'électrode positive pour pile secondaire à électrolyte non aqueux, et pile secondaire à électrolyte non aqueux WO2017164237A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201780030656.XA CN109155413B (zh) 2016-03-24 2017-03-22 正极活性物质和其制造方法、糊剂和二次电池
US16/086,746 US20190051929A1 (en) 2016-03-24 2017-03-22 Positive electrode active material for non-aqueous electrolyte secondary battery and method for manufacturing the same, positive electrode mixed material paste for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2016-060745 2016-03-24
JP2016060745 2016-03-24
JP2016-118644 2016-06-15
JP2016118644 2016-06-15
JP2016-248296 2016-12-21
JP2016248296A JP7135269B2 (ja) 2016-03-24 2016-12-21 非水系電解質二次電池用正極活物質とその製造方法、非水系電解質二次電池用正極合材ペーストおよび非水系電解質二次電池

Publications (1)

Publication Number Publication Date
WO2017164237A1 true WO2017164237A1 (fr) 2017-09-28

Family

ID=59900238

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/011450 WO2017164237A1 (fr) 2016-03-24 2017-03-22 Matière active d'électrode positive pour pile secondaire à électrolyte non aqueux et son procédé de fabrication, pâte de matière d'électrode positive pour pile secondaire à électrolyte non aqueux, et pile secondaire à électrolyte non aqueux

Country Status (1)

Country Link
WO (1) WO2017164237A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10302779A (ja) * 1997-04-25 1998-11-13 Sony Corp 正極活物質の製造方法
JPH10340726A (ja) * 1997-06-04 1998-12-22 Mitsui Mining & Smelting Co Ltd リチウム二次電池用正極活物質の製造法及びこれを用いた電池
JP2010080394A (ja) * 2008-09-29 2010-04-08 Sumitomo Metal Mining Co Ltd 非水系電解質二次電池用正極活物質及びその製造方法、並びに非水系電解質二次電池
JP2011023121A (ja) * 2009-07-13 2011-02-03 Nippon Chem Ind Co Ltd リチウム二次電池用正極活物質、その製造方法及びリチウム二次電池
JP2012003891A (ja) * 2010-06-15 2012-01-05 Nissan Motor Co Ltd 活物質の製造方法
JP2012252844A (ja) * 2011-06-01 2012-12-20 Sumitomo Metal Mining Co Ltd 非水系電解質二次電池用正極活物質の前駆体となる遷移金属複合水酸化物とその製造方法、その非水系電解質二次電池用正極活物質とその製造方法、ならびに該正極活物質を用いた非水系電解質二次電池
JP2012256435A (ja) * 2011-06-07 2012-12-27 Sumitomo Metal Mining Co Ltd ニッケルマンガン複合水酸化物粒子とその製造方法、非水系電解質二次電池用正極活物質とその製造方法、ならびに非水系電解質二次電池
JP2015130340A (ja) * 2014-01-06 2015-07-16 深▲セン▼市貝特瑞新能源材料股▲ふん▼有限公司 リチウムニッケルコバルトアルミニウム酸化物複合正極材料、その製造方法及びリチウムイオン二次電池

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10302779A (ja) * 1997-04-25 1998-11-13 Sony Corp 正極活物質の製造方法
JPH10340726A (ja) * 1997-06-04 1998-12-22 Mitsui Mining & Smelting Co Ltd リチウム二次電池用正極活物質の製造法及びこれを用いた電池
JP2010080394A (ja) * 2008-09-29 2010-04-08 Sumitomo Metal Mining Co Ltd 非水系電解質二次電池用正極活物質及びその製造方法、並びに非水系電解質二次電池
JP2011023121A (ja) * 2009-07-13 2011-02-03 Nippon Chem Ind Co Ltd リチウム二次電池用正極活物質、その製造方法及びリチウム二次電池
JP2012003891A (ja) * 2010-06-15 2012-01-05 Nissan Motor Co Ltd 活物質の製造方法
JP2012252844A (ja) * 2011-06-01 2012-12-20 Sumitomo Metal Mining Co Ltd 非水系電解質二次電池用正極活物質の前駆体となる遷移金属複合水酸化物とその製造方法、その非水系電解質二次電池用正極活物質とその製造方法、ならびに該正極活物質を用いた非水系電解質二次電池
JP2012256435A (ja) * 2011-06-07 2012-12-27 Sumitomo Metal Mining Co Ltd ニッケルマンガン複合水酸化物粒子とその製造方法、非水系電解質二次電池用正極活物質とその製造方法、ならびに非水系電解質二次電池
JP2015130340A (ja) * 2014-01-06 2015-07-16 深▲セン▼市貝特瑞新能源材料股▲ふん▼有限公司 リチウムニッケルコバルトアルミニウム酸化物複合正極材料、その製造方法及びリチウムイオン二次電池

Similar Documents

Publication Publication Date Title
JP7077943B2 (ja) 非水系電解質二次電池用正極活物質とその製造方法、非水系電解質二次電池用正極合材ペーストおよび非水系電解質二次電池
JP6777081B2 (ja) 非水電解質二次電池用正極活物質および非水電解質二次電池
JP7135269B2 (ja) 非水系電解質二次電池用正極活物質とその製造方法、非水系電解質二次電池用正極合材ペーストおよび非水系電解質二次電池
JP7013871B2 (ja) 非水系電解質二次電池用正極活物質とその製造方法、非水系電解質二次電池用正極合材ペーストおよび非水系電解質二次電池
JP7024292B2 (ja) 非水系電解質二次電池用正極活物質とその製造方法、及び非水系電解質二次電池
WO2018043515A1 (fr) Substance active d'électrode positive pour batterie secondaire à électrolyte non aqueux et son procédé de production, bouillie de mélange d'électrode pour batterie secondaire à électrolyte non aqueux, et batterie secondaire à électrolyte non aqueux
CN111295786B (zh) 非水电解质二次电池正极活性物质及制造方法、及使用正极活性物质的非水电解质二次电池
CN111295785B (zh) 非水电解质二次电池正极活性物质及制造方法、及使用正极活性物质的非水电解质二次电池
KR20130051012A (ko) 비수계 전해질 2차 전지용 정극 활물질과 그의 제조 방법, 및 상기 정극 활물질을 이용한 비수계 전해질 2차 전지
JP2017134996A (ja) 非水系電解質二次電池用正極活物質とその製造方法、及び該正極活物質を用いた非水系電解質二次電池
US11967713B2 (en) Positive electrode active material for non-aqueous electrolyte secondary battery comprising tungsten coating film, and non-aqueous electrolyte secondary battery
WO2016104305A1 (fr) Matériau actif d'électrode positive pour une pile rechargeable à électrolyte non aqueux, procédé permettant de fabriquer ledit matériau et pile rechargeable à électrolyte non aqueux dans laquelle ledit matériau est utilisé
JP2019046716A (ja) 非水系電解質二次電池用正極活物質とその製造方法、および、非水系電解質二次電池
JP6848199B2 (ja) 非水系電解質二次電池用正極材料、該正極材料を用いた非水系電解質二次電池、および非水系電解質二次電池用正極材料の製造方法。
JP2018195419A (ja) 非水系電解質二次電池用正極材料、該正極材料を用いた非水系電解質二次電池、および非水系電解質二次電池用正極材料の製造方法。
WO2017034000A1 (fr) Matériau actif d'électrode positive pour pile rechargeable à électrolyte non aqueux et procédé de production dudit matériau, et pile rechargeable à électrolyte non aqueux
JP2018032543A (ja) 非水系電解質二次電池用正極活物質とその製造方法、及び非水系電解質二次電池
JP6819859B2 (ja) 非水系電解質二次電池用正極材料、該正極材料を用いた非水系電解質二次電池、および非水系電解質二次電池用正極材料の製造方法。
JP2019212365A (ja) リチウムイオン二次電池用正極活物質及びその製造方法、並びにその正極活物質を用いたリチウムイオン二次電池
JP7020101B2 (ja) 非水系電解質二次電池用正極活物質、非水系電解質二次電池用正極活物質の製造方法、非水系電解質二次電池
JP6969239B2 (ja) 非水系電解質二次電池用正極活物質およびその製造方法
WO2017164237A1 (fr) Matière active d'électrode positive pour pile secondaire à électrolyte non aqueux et son procédé de fabrication, pâte de matière d'électrode positive pour pile secondaire à électrolyte non aqueux, et pile secondaire à électrolyte non aqueux
JP6819860B2 (ja) 非水系電解質二次電池用正極材料、該正極材料を用いた非水系電解質二次電池、および非水系電解質二次電池用正極材料の製造方法。
JP6919175B2 (ja) 非水系電解質二次電池用正極材料、該正極材料を用いた非水系電解質二次電池、および非水系電解質二次電池用正極材料の製造方法。
JP2021005474A (ja) リチウムイオン二次電池用正極活物質とその製造方法、及び、リチウムイオン二次電池

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17770277

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17770277

Country of ref document: EP

Kind code of ref document: A1