WO2020153409A1 - Oxyde de titane, procédé de production d'oxyde de titane et batterie rechargeable au lithium utilisant un matériau actif d'électrode contenant de l'oxyde de titane - Google Patents

Oxyde de titane, procédé de production d'oxyde de titane et batterie rechargeable au lithium utilisant un matériau actif d'électrode contenant de l'oxyde de titane Download PDF

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WO2020153409A1
WO2020153409A1 PCT/JP2020/002158 JP2020002158W WO2020153409A1 WO 2020153409 A1 WO2020153409 A1 WO 2020153409A1 JP 2020002158 W JP2020002158 W JP 2020002158W WO 2020153409 A1 WO2020153409 A1 WO 2020153409A1
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lithium
lithium titanate
sample
titanium oxide
titanium
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PCT/JP2020/002158
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English (en)
Japanese (ja)
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永井　秀明
秋本　順二
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国立研究開発法人産業技術総合研究所
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Priority to CN202080010504.5A priority Critical patent/CN113348150B/zh
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/24—Electrodes characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/46—Metal oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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 titanium oxide having a large charge/discharge capacity, a method for producing the same, an electrode active material containing the titanium oxide, and an electricity storage device having the electrode active material.
  • Lithium secondary batteries are expected to be put to practical use as large-sized batteries for hybrid cars and electric power load leveling systems, and their importance is increasing.
  • This lithium secondary battery mainly comprises a positive electrode and a negative electrode each containing a material capable of reversibly occluding and releasing lithium, and a separator or a solid electrolyte containing a non-aqueous electrolyte solution.
  • lithium cobalt oxide LiCoO 2
  • lithium manganese oxide LiMn 2 O 4
  • lithium titanate Li 4 Ti 5 O 12
  • metal-based materials such as metallic lithium, lithium alloys and tin alloys
  • carbon-based materials such as graphite and MCMB (mesocarbon microbeads).
  • the voltage of the battery is determined by the difference in chemical potential depending on the lithium content in each active material. It is a feature of the lithium secondary battery that is excellent in energy density that a large potential difference can be formed by combining the positive electrode active material and the negative electrode active material. Particularly, in a lithium secondary battery including a positive electrode containing a lithium cobalt oxide (LiCoO 2 ) active material and a negative electrode containing a carbon material, a voltage close to 4 V is possible. In addition, this lithium secondary battery is widely adopted because it has a large charge/discharge capacity, which is the amount of lithium that can be detached/inserted from the electrode, and has high safety.
  • LiCoO 2 lithium cobalt oxide
  • lithium secondary battery including a positive electrode containing a spinel type lithium manganese oxide (LiMn 2 O 4 ) active material and a negative electrode containing a spinel type lithium titanium oxide (Li 4 Ti 5 O 12 ) active material, Lithium occlusion/desorption reactions are easily performed smoothly. Further, this lithium secondary battery has been found to be excellent in a long-term charge/discharge cycle because it has less change in crystal lattice volume due to reaction, and has been put into practical use.
  • the voltage of the lithium secondary battery including the positive electrode containing the titanium oxide active material and the negative electrode made of lithium metal is only about 1 to 2V. Therefore, materials having various crystal structures have been studied as an electrode active material for a negative electrode corresponding to a positive electrode containing a titanium oxide active material.
  • TiO 2 (B) Spinel type lithium titanium oxide Li 4 Ti 5 O 12 or titanium dioxide having a sodium bronze type crystal structure
  • TiO 2 (B) titanium dioxide having a sodium bronze type crystal structure
  • Ti- A titanium oxide containing H in a composition such as an OH-based titanium structure
  • H 2 Ti 12 O 25 hereinafter, referred to as “H 2 Ti 12 O 25 ”, which is titanium oxide containing H element in the crystal structure.
  • HTO active materials
  • active materials such as monoclinic titanium-niobium composite oxides are drawing attention as electrode materials (Patent Documents 1 and 2, Non-Patent Documents 1 and 2).
  • Li 4 Ti 5 O 12 has a theoretical capacity of about 175 mAh/g and cannot be expected to have a large capacity.
  • TiO 2 (B) having an initial charge capacity of more than 300 mAh/g and titanium oxide containing H in the composition have been synthesized, these have a problem that the initial irreversible capacity is large.
  • HTO has a smaller initial irreversible capacity than TiO 2 (B), but has an initial charging capacity of about 230 mAh/g. For this reason, the HTO has a large capacity by miniaturizing titanium oxide containing an alkali metal other than lithium, such as Na 2 Ti 3 O 7 and K 2 Ti 4 O 9, which are the starting materials, but it is sufficient. I can't say.
  • Some monoclinic titanium-niobium composite oxides have an initial charge capacity of about 280 mAh/g and a relatively small irreversible capacity.
  • the price of niobium to titanium is about 6 times (2007), and the ratio of niobium to titanium in the crust is 1/220.
  • the advent of titanium oxide that has a large charge/discharge capacity, is expensive, and does not contain an element with a small resource amount is desired.
  • the present invention has been made in view of such circumstances, and provides a titanium oxide having a large charge/discharge capacity, an electrode active material containing the titanium oxide, and an electricity storage device having the electrode active material. With the goal.
  • the present inventor has used a lithium titanate having a primary particle diameter of 10 nm or more and less than 100 nm as a starting material, and thus has the general formula H 2 Ti 12 containing no different alkali metal other than lithium such as sodium and potassium.
  • the inventors have found that a high-capacity titanium oxide represented by the chemical composition of O 25 can be synthesized, and completed the present invention.
  • the titanium oxide of the present invention is represented by the general formula H 2 Ti 12 O 25 , and the amount of alkali metals other than lithium detected by ICP emission spectroscopy is less than the lower limit of quantification.
  • the electrode active material of the present invention contains the titanium oxide of the present invention.
  • the electricity storage device of the present invention has the electrode active material of the present invention.
  • the method for producing a proton exchanger of lithium titanate according to the present invention is a method in which a titanium compound in a titanium raw material containing a titanium compound and a lithium compound in a lithium raw material containing a lithium compound are crystal-grown together to obtain a titanic acid.
  • the method for producing a titanium oxide according to the present invention is a method for crystallizing a titanium compound in a titanium raw material containing a titanium compound and a lithium compound in a lithium raw material containing a lithium compound together to obtain lithium titanate.
  • Lithium oxide synthesis step, heat treatment of lithium titanate obtained in the lithium titanate synthesis step, and heat treatment of lithium titanate obtained in the heat treatment step of lithium titanate It has a proton exchange step and a proton exchanger heat treatment step of heat-treating the lithium titanate proton exchanger obtained in the lithium/proton exchange step.
  • a titanium oxide having a large charge/discharge capacity, an electrode active material containing this titanium oxide, and an electricity storage device having this electrode active material can be obtained.
  • the titanium oxide of the present invention is represented by the general formula H 2 Ti 12 O 25 , and the amount of alkali metals other than lithium detected by ICP emission spectroscopy is less than the lower limit of quantification.
  • the electrode active material of the present invention contains the titanium oxide of the present invention.
  • An electricity storage device such as the lithium secondary battery of the present invention has the electrode active material of the present invention.
  • the method for producing a lithium titanate proton exchanger according to the present invention includes a lithium titanate synthesis step, a lithium titanate heat treatment step, and a lithium/proton exchange step.
  • the method for producing titanium oxide of the present invention includes a lithium titanate synthesis step, a lithium titanate heat treatment step, a lithium/proton exchange step, and a proton exchanger heat treatment step.
  • a lithium titanate synthesis step for example, a titanium raw material and a lithium raw material are mixed, crystal growth is performed to synthesize lithium titanate, and the lithium titanate is heat-treated. It is obtained by exchanging lithium for a proton (lithium/proton exchange), and subjecting this lithium titanate proton exchanger to a heat treatment.
  • the titanium compound in the titanium raw material containing the titanium compound and the lithium compound in the lithium raw material containing the lithium compound are crystal-grown together to obtain lithium titanate. More specifically, a mixture containing a titanium raw material and a lithium raw material is crystal-grown by a hydrothermal synthesis method or the like.
  • the titanium raw material is not particularly limited as long as it contains a titanium compound, and examples thereof include oxides such as TiO, Ti 2 O 3 , and TiO 2 , TiO(OH) 2 , TiO 2 ⁇ xH 2 O Examples thereof include titanium oxide hydrate represented by (optional), inorganic titanium compounds such as titanium chloride and titanium sulfate, and organic titanium compounds such as titanium isopropoxide and titanium butoxide.
  • titanium oxide and titanium oxide hydrate are particularly preferable, and titanium dioxide such as anatase and rutile, metatitanic acid represented by TiO(OH) 2 or TiO 2 ⁇ H 2 O, and TiO 2 ⁇ 2H 2 O are used.
  • the orthotitanic acid represented, a mixture thereof, or the like can be used as the titanium raw material.
  • the lithium compound is not particularly limited as long as it is a compound containing lithium, and examples thereof include oxides such as Li 2 O and Li 2 O 2 , salts such as Li 2 CO 3 and LiNO 3 , hydroxides such as LiOH and the like. Are listed.
  • the lithium raw material may contain other alkali metal compounds such as sodium compounds and potassium compounds, and their content is not particularly limited as long as it does not hinder the production of lithium titanate.
  • the size of lithium ion is significantly smaller than that of sodium ion or potassium ion (when compared with the same four-coordinate structure, the radius of lithium ion: 0.059 nm, the radius of sodium ion: 0.099 nm, the radius of potassium ion: 0.137 nm), sodium ions and potassium ions cannot enter the lithium ion sites while maintaining the crystal structure of lithium titanate.
  • the ratio of the lithium compound contained in the lithium raw material is 0.1 or more.
  • the sodium compound include oxides such as Na 2 O and Na 2 O 2 , salts such as Na 2 CO 3 and NaNO 3 , and hydroxides such as NaOH.
  • the potassium compound include oxides such as K 2 O and K 2 O 2 , salts such as K 2 CO 3 and KNO 3 , and hydroxides such as KOH.
  • the mixture containing the titanium raw material and the lithium raw material may be obtained by dry-mixing the titanium raw material and the lithium raw material, or may be obtained by dissolving or suspending the titanium raw material and the lithium raw material in a liquid such as water, ethanol, or a mixture thereof. May be.
  • This dissolution or suspension is performed at a temperature not lower than room temperature and not higher than the boiling point of the solvent.
  • hydrogen peroxide, ammonia, NH 4 F, glucose or the like may be added in order to promote the dissolution or complex formation of the titanium raw material and enhance the reactivity.
  • various surfactants and organic salts or inorganic salts such as lithium sulfate may be added.
  • organic salts or inorganic salts such as lithium sulfate
  • carbon particles, carbon nanotubes, graphene, graphene oxide, etc. may be added in an amount of 0.05 wt% to 10 wt% in terms of C. These carbon-based materials may be previously compounded with a titanium raw material or a lithium raw material.
  • a mixture containing a titanium raw material and a lithium raw material is crystal-grown to obtain lithium titanate.
  • a liquid phase method such as a co-precipitation method, a uniform precipitation method, a compound precipitation method, a metal alkoxide method, a hydrothermal synthesis method, a sol-gel method, which is a general method for synthesizing ceramic fine particles, or a solid-phase reaction method.
  • a solid phase method such as or a thermal decomposition method can be used.
  • lithium titanate having an average particle size of primary particles of 10 nm or more and less than 100 nm and having a rock salt type crystal structure or a monoclinic crystal structure is obtained.
  • a method for calculating the average particle size of primary particles of lithium titanate will be described later.
  • Examples of lithium titanate having a rock salt type crystal structure include Li 2 TiO 3 , Li 2 Ti 2 O 4 , LiTi 2 O 4 , and Li 4 Ti 5 O 12 .
  • lithium titanate having a monoclinic crystal structure examples include Li 2 TiO 3 and Li 2 Ti 6 O 13 .
  • Li 2 TiO 3 is preferable as a raw material of the titanium oxide of the present invention.
  • Li 2 TiO 3 having a primary particle having an average particle size of 10 nm or more and less than 100 nm and a monoclinic crystal structure complexed in a rock salt type crystal structure is more preferable as a raw material of the titanium oxide of the present invention. ..
  • the rock salt type crystal structure belongs to the cubic system.
  • oxygen which is a constituent element, forms an anion
  • lithium and titanium form a cation, forming face-centered cubic lattices.
  • the monoclinic crystal structure has a basic lattice in which crystal axes are all different in length and only one axis angle is not right angle. The symmetry of monoclinic crystals is lower than that of cubic crystals.
  • Li 2 TiO 3 having a monoclinic crystal structure is a two-dimensional plane of oxygen in the c-axis direction, a two-dimensional plane of lithium and titanium in an atomic ratio of 1:2, a two-dimensional plane of oxygen, and a two-dimensional plane composed of only lithium. The dimensional plane is repeated and arranged regularly.
  • a two-dimensional plane of oxygen as anion and a two-dimensional plane of lithium or titanium as a cation are regularly arranged alternately.
  • Li 2 TiO 3 having a rock salt type crystal structure with high symmetry to Li 2 having a monoclinic crystal structure with low symmetry It can be changed to 2 TiO 3 .
  • Li 2 TiO monoclinic crystal structure is complexed in a rock-salt crystal structure 3
  • a part of Li 2 TiO 3 is monoclinic crystal structure of Li 2 TiO 3 having a rock-salt crystal structure and which was replaced, and Li 2 TiO 3 having a rock-salt crystal structure, is distinguished from a simple mixture of Li 2 TiO 3 having a monoclinic crystal structure.
  • the hydrothermal synthesis method is particularly preferable as a method for crystallizing a mixture containing a titanium raw material and a lithium raw material to obtain lithium titanate having a rock salt type crystal structure.
  • the reaction temperature and reaction time in the hydrothermal synthesis method are not particularly limited as long as sufficient reaction and crystal growth can be performed, but a reaction temperature of 150° C. or higher and a reaction time of 3 hours or longer are preferable.
  • the obtained lithium titanate can be recovered by a known method such as filtration, spontaneous sedimentation or centrifugation.
  • the recovered lithium titanate can be dried by a known method, but it is preferably dried by vacuum drying or the like.
  • LiOH, LiOH.H 2 O and the like are particularly preferable as the lithium raw material.
  • Alkali metal raw materials other than lithium raw materials such as sodium compounds such as NaOH and potassium compounds such as KOH may be contained in the mixture.
  • the alkali metal raw material also has a function of promoting the dissolution of the titanium raw material in the lithium titanate synthesis process. Therefore, in the lithium titanate synthesis process, a large amount of alkali metal raw material may be used with respect to the titanium raw material.
  • the ratio of the weight of the alkali metal raw material to the weight of the titanium raw material is 1 time (the amount of the alkali metal raw material to the amount of the titanium raw material is The ratio is preferably about 2.3 times or more, and more preferably 1.5 times or more.
  • the ratio of the amount of the alkali metal element contained in the alkali metal raw material to the substance amount of the titanium element contained in the titanium raw material that is, the ratio of the alkali metal element contained in the alkali metal raw material
  • the amount of substance/the amount of substance of titanium element contained in the titanium raw material is preferably 5 or more, and more preferably 10 or more.
  • Lithium titanate having a rock salt type crystal structure obtained by a hydrothermal synthesis method shows a series of peaks derived from the target rock salt type crystal structure of lithium titanate in a powder XRD measurement, and in addition to this, 19 It shows a broad peak with a peak top at °-21°.
  • This broad peak is due to diffuse scattering due to defects such as a lithium atom of lithium titanate having a rock salt type crystal structure and a defect of a lattice site where the titanium atom exists. It is considered that lithium titanate showing this broad peak has an action of inhibiting rearrangement due to diffusion of atoms necessary for producing titanium dioxide such as rutile and anatase.
  • Lithium titanate obtained by the hydrothermal synthesis method contains solvent molecules.
  • the solvent molecules penetrate into the crystal structure of lithium titanate to reduce the crystallinity of lithium titanate. Therefore, the crystal structure of lithium titanate is distorted by the subsequent lithium/proton exchange step, and the basic skeleton of lithium titanate is easily destroyed. Then, in the dehydration process in the subsequent proton exchanger heat treatment step, the proton exchanger of lithium titanate is likely to change to titanium dioxide such as anatase or rutile.
  • the production of titanium dioxide leads to deterioration of performance such as reduction in capacity of HTO and therefore needs to be suppressed.
  • a method for synthesizing lithium titanate having a monoclinic crystal structure a method of heat-treating Li 2 TiO 3 having a rock salt type crystal structure to change the phase to Li 2 TiO 3 having a monoclinic crystal structure is performed.
  • a method of directly synthesizing a mixture of a titanium raw material and a lithium raw material by a solid-phase reaction method there is a method of directly synthesizing a mixture of a titanium raw material and a lithium raw material by a solid-phase reaction method.
  • a method of synthesizing lithium titanate having a monoclinic crystal structure by a solid-phase reaction method is particularly preferable.
  • the method of heat-treating Li 2 TiO 3 having a rock salt type crystal structure to change the phase to Li 2 TiO 3 having a monoclinic crystal structure it is preferable to perform heat treatment at a temperature of 600° C. or higher and 1150° C. or lower. This is because even if the heat treatment is performed at a temperature lower than 600° C., the phase change is difficult to proceed, and if the heat treatment is performed at a temperature higher than 1150° C., the products are easily sintered with each other. When the products are sintered together, the final target titanium oxide has a small charge/discharge capacity.
  • the heat treatment temperature is more preferably 700° C. or higher and 900° C. or lower.
  • the heat treatment time is usually 0.5 to 100 hours, preferably 1 to 30 hours.
  • the atmosphere of this heat treatment is not particularly limited, and it is possible to perform heat treatment in an oxygen gas atmosphere such as air, or an inert gas atmosphere such as nitrogen or argon.
  • lithium titanate having a monoclinic crystal structure is directly synthesized from a mixture containing a titanium raw material and a lithium raw material by a solid phase reaction method
  • Li 2 CO 3 or the like is particularly preferable as the lithium raw material.
  • the mixing ratio of the titanium raw material and the lithium raw material is adjusted according to the composition of titanium and lithium of the target lithium titanate.
  • the firing temperature is preferably 600°C or higher and 1000°C or lower. This is because if the firing temperature is less than 600° C., the reaction is difficult to proceed, and if the firing temperature exceeds 1000° C., the products tend to sinter.
  • the firing temperature is more preferably 700° C. or higher and 900° C. or lower.
  • the firing atmosphere is not particularly limited, and normally firing may be performed in an oxygen gas atmosphere such as air or in an inert gas atmosphere such as nitrogen or argon.
  • the lithium titanate obtained in the lithium titanate synthesis step is heat-treated.
  • heat treatment is performed so that a part of Li 2 TiO 3 having a rock salt type crystal structure is changed to Li 2 TiO 3 having a monoclinic crystal structure, a monoclinic crystal structure is formed in the rock salt type crystal structure.
  • a composite Li 2 TiO 3 is obtained.
  • arrangement of lattice sites of the titanium atoms is compared with Li 2 TiO 3 with only Li 2 TiO 3 and monoclinic crystal structure with only rock salt type crystal structure not It becomes a rule.
  • Li 2 TiO 3 This was complexed, compared with Li 2 TiO 3 with only only or monoclinic crystal structure rock salt type crystal structure, after the heat treatment step proton exchange of lithium titanate During the dehydration process, it becomes difficult to convert to titanium dioxide such as anatase and rutile.
  • Heat treatment such as a portion of Li 2 TiO 3 having a rock-salt crystal structure is changed to Li 2 TiO 3 having a monoclinic crystal structure in an oxygen gas-containing atmosphere such as air or nitrogen or argon etc. Perform in an inert gas atmosphere.
  • an oxygen gas-containing atmosphere such as air or nitrogen or argon etc.
  • the temperature of this heat treatment is preferably 100° C. or higher and 600° C. or lower.
  • Li 2 TiO 3 having a rock salt type crystal structure When Li 2 TiO 3 having a rock salt type crystal structure is heat-treated at less than 100° C., the phase change hardly progresses, and when heat-treated at a temperature of more than 600° C., most of the rock salt type crystal structure is changed to a monoclinic crystal structure. is there.
  • the temperature of this heat treatment is more preferably 200°C to 500°C.
  • the time for this heat treatment is usually 0.5 to 100 hours, preferably 1 to 30 hours.
  • the full width at half maximum of the peak at the time of X-ray diffraction of the sample having high crystallinity becomes narrow.
  • the full width half maximum width is obtained as a peak width (unit: °) at a height half the peak height.
  • the full width at half maximum of the main peak exhibited by the heat treated lithium titanate that has undergone the lithium titanate heat treatment step is equal to It is preferably reduced by 5% or more and less than 40% from the full width half maximum width, and more preferably 10% or more and less than 35%.
  • Lithium titanate Li 2 TiO 3 having a rock salt type crystal structure has a main peak at around 43.6°.
  • the lithium titanate obtained in the lithium titanate synthesis step may have structural defects in the crystal structure, oxygen deficiency/excess oxygen, and lithium deficiency/excess lithium, as long as it shows a powder XRD pattern specific to lithium titanate.
  • the shape of the lithium titanate is, for example, an acicular shape such as a needle shape, a rod shape, a column shape, a spindle shape, a cylindrical shape, or a fibrous shape, an isotropic shape such as a spherical shape or a polyhedral shape, or an amorphous shape.
  • the average particle size of the lithium titanate primary particles is preferably 10 nm or more and less than 100 nm, and more preferably 20 nm or more and less than 60 nm. It should be noted that a dispersion/atomization operation such as crushing or crushing may be added to lithium titanate so that the crystal structure is not impaired or the primary particle size is not changed.
  • the lithium titanate obtained in the lithium titanate synthesis step is heat treated.
  • This heat treatment is carried out, for example, in the temperature range of 100° C. to 800° C., preferably in the temperature range of 200° C. to 700° C., more preferably in the temperature range of 250° C. to 600° C., usually for 0.5 hour to 100 hours, preferably for 1 hour. This is done by heating for 30 hours.
  • the heating atmosphere is not particularly limited, and usually heating can be performed in an oxygen gas atmosphere such as air or an inert gas atmosphere such as nitrogen or argon. This heating removes solvent molecules penetrating into the crystal structure of lithium titanate. Therefore, the crystallinity of lithium titanate is increased, the crystal structure becomes more stable, and the production of titanium dioxide due to the solvent molecules as described above can be suppressed.
  • the lithium in the heat-treated lithium titanate is exchanged for protons. That is, by immersing lithium titanate in an acidic aqueous solution and applying a proton exchange reaction, a proton exchanger of lithium titanate in which almost all of the lithium in the heat-treated lithium titanate is exchanged with hydrogen can be obtained. At this time, it is preferable to disperse lithium titanate in an acidic aqueous solution, hold it for a certain period of time, then separate it by filtration with a filter or centrifuge and dry.
  • the acid used in the lithium/proton exchange step is preferably an aqueous solution of any concentration containing one or more of hydrochloric acid, sulfuric acid, and nitric acid, more preferably 0.1N to 1.0N dilute hydrochloric acid.
  • the processing time for exchanging lithium for protons is 10 hours to 10 days, preferably 1 day to 7 days. In order to shorten the treatment time, the acid aqueous solution may be replaced with a fresh one.
  • the treatment temperature when exchanging lithium for protons is preferably room temperature (20° C.) or higher and lower than 100° C. For the drying, a known method can be applied, but vacuum drying or the like is preferable.
  • the lithium titanate proton exchanger thus obtained was analyzed for the amount of lithium remaining from the lithium raw material by optimizing the conditions of the lithium/proton exchange step, and ICP emission spectroscopy which is a wet chemical analysis. It is possible to reduce it to less than the lower limit of quantification in analysis.
  • Wet chemical analysis is a method in which a sample is made into a solution, and then an element is measured using various analytical methods such as a titration method, a gravimetric method, an atomic absorption spectrophotometric method, and an ICP emission spectroscopic analysis method. It is generally used as a quantitative method.
  • the lower limit of quantification of ICP emission spectroscopy is said to be about 5 ppm when converted to the element concentration in a solid sample.
  • the lithium titanate proton exchanger obtained in the lithium/proton exchange step is heat treated.
  • heat treatment of a lithium titanate proton exchanger in an oxygen gas-containing atmosphere such as air, an inert gas atmosphere such as nitrogen or argon, a hydrogen gas-containing atmosphere, or under reduced pressure causes a desired dehydration reaction.
  • titanium oxide is obtained.
  • the temperature of this heat treatment is preferably 200°C or higher and 600°C or lower, more preferably 260°C or higher and 500°C or lower, and further preferably 300°C or higher and 480°C or lower.
  • the heat treatment time is usually 0.5 hour to 100 hours, preferably 1 hour to 30 hours, and if the heat treatment temperature is high, the heat treatment time can be shortened. Further, by reducing the pressure of the heat treatment atmosphere, it is possible to suppress side reactions involving the production of other titanium oxides such as anatase and rutile.
  • the heat treatment is preferably performed under a reduced pressure of less than 100 Pa, more preferably performed under a reduced pressure of less than 50 Pa, and even more preferably performed under a reduced pressure of less than 30 Pa.
  • the method for producing titanium oxide further comprises an assembling step of assembling lithium titanate, a proton exchanger of lithium titanate, or primary particles of titanium oxide to obtain secondary particles.
  • the assembling step for example, heat treatment or proton exchange is performed after granulating lithium titanate, heat treatment is performed after granulating a proton exchange material of lithium titanate, or obtained by heat treatment of a proton exchange material of lithium titanate. Granulate titanium oxide.
  • Examples of the granulation include dry granulation, stirring granulation and consolidation granulation, but dry granulation is preferable. This is because it is easy to adjust the particle size and shape of the secondary particles.
  • the dry granulation lithium titanate, a proton exchange material of lithium titanate, or a slurry containing a heat-treated proton exchange material of lithium titanate is dehydrated, followed by a method of drying and pulverizing, after dehydrating this slurry. Examples include a method of molding and drying, a method of spray drying this slurry, and the like. Among these, a method of spray drying a slurry containing lithium titanate, a proton exchange material of lithium titanate, or a heat-treated proton exchange material of lithium titanate is industrially preferable.
  • a spray dryer such as a disc type, a pressure nozzle type, a two-fluid nozzle type, or a four-fluid nozzle type may be selected depending on the properties of the slurry and the processing capacity.
  • the control of the secondary particle size for example, the solid content concentration in the slurry, disk rotation speed in the disk type, pressure nozzle type, two-fluid nozzle type, or adjust the spray pressure and nozzle diameter in the four-fluid nozzle type, This can be done by controlling the size of the sprayed droplets.
  • the inlet temperature of the drying section of the spray dryer is 150° C. or higher and 250° C. or lower and the outlet temperature is 70° C. or higher and 120° C. or lower.
  • the slurry may contain an organic binder in the case where the viscosity of the slurry is low and it is difficult to granulate, or to make it easier to control the particle size.
  • organic binder include vinyl compounds such as polyvinyl alcohol and polyvinylpyrrolidone, hydroxylethyl cellulose, carboxymethyl cellulose, methyl cellulose, and cellulose compounds such as ethyl cellulose, gelatin, gum arabic, casein, sodium caseinate, and ammonium caseinate.
  • protein-based compounds such as sodium acrylate, ammonium polyacrylate and other acrylic acid-based compounds, starch, dextrin, agar, and natural polymer compounds such as sodium alginate, and at least synthetic polymer compounds such as polyethylene glycol
  • an organic binder that does not contain an inorganic component such as soda is preferable, because it is easily decomposed and volatilized by heat treatment and there is no contact between the different alkali metal and the sample.
  • a proton exchanger of lithium titanate On the particle surface of lithium titanate, a proton exchanger of lithium titanate, and primary or secondary particles of titanium oxide, carbon, an inorganic compound such as silica or alumina, and an organic compound such as a surfactant or a coupling agent. At least one of the compounds may be coated.
  • This coating layer may be formed by laminating two or more kinds, or may be composed of a mixture or compound of two or more kinds. Since the electric conductivity is improved, when a lithium titanate proton exchanger or a titanium oxide is used as an electrode active material, lithium titanate, a lithium titanate proton exchanger or a carbon oxide on the surface of titanium oxide particles is used. Is preferably coated.
  • the ratio of the weight of the carbon coating to the weight of lithium titanate, a proton exchanger of lithium titanate, or titanium oxide is preferably 0.05% or more and 10% or less in terms of C.
  • carbon particles such as carbon particles, carbon nanotubes, graphene, and graphene oxide are previously added to lithium titanate, or when carbon particles are added when secondary particles are formed by spray drying or the like, It is preferable to adjust the above ratio so as to be 0.05% or more and 10% or less together with the weight of carbon added in advance.
  • the carbon content can be calculated by thermogravimetric analysis in air, CHN analysis method, high-frequency combustion method, etc. of a sample that has been dehydrated by heating in an inert gas atmosphere such as N 2 or Ar.
  • HTO obtained by the heat treatment step of the proton exchanger may have a peak at the same peak position as in Patent Document 2 and Non-Patent Document 2 in powder XRD measurement using Cu-K ⁇ as a radiation source, and has a crystal structure. There may be defects, oxygen deficiency/excess oxygen, and hydrogen deficiency/excess hydrogen. Moreover, the peak intensity ratios may be different. The difference in the peak intensity ratio is due to the fact that the crystal growth of a specific crystal face became poor due to the refinement of the primary particles, and in particular, the peak derived from the (110) plane appearing around 25° and around 48° were observed. The peak derived from the (020) plane that appears appears to be extremely weak in intensity, or overlaps with neighboring peaks, making it difficult to distinguish.
  • titanium dioxide such as anatase and rutile may be contained in the HTO in a small amount as an impurity, but if it is a small amount, it hardly affects the battery characteristics of the HTO.
  • the content of titanium dioxide in HTO is the peak height I 0 appearing in the vicinity of 28° of the (003) plane of HTO obtained by powder XRD measurement and the main peak of titanium dioxide (appearing in the vicinity of 25° in anatase (101). It is calculated by the ratio I 1 /I 0 of the peak height I 1 of the (110) plane that appears near 27° in the plane and rutile.
  • the peak height is the height from the base to the peak apex based on the straight line connecting the heights of the minimum points before and after the peak.
  • the I 1 /I 0 of HTO is preferably 5 times or less, more preferably 3 times or less, and further preferably 2.5 times or less.
  • the shape of the HTO is, for example, an acicular shape such as a needle shape, a rod shape, a column shape, a spindle shape, a cylinder shape, or a fibrous shape, an isotropic shape such as a spherical shape or a polyhedral shape, or an amorphous shape.
  • a preferable HTO shape is an isotropic shape such as a spherical shape or a polyhedral shape.
  • the average particle size of the primary particles of HTO is preferably 10 nm or more and less than 100 nm, more preferably 20 nm or more and less than 60 nm, and further preferably 30 nm or more and less than 50 nm.
  • the active material used for the lithium secondary battery needs a site for storing lithium and a diffusion path for the lithium to move to the storage site inside the active material.
  • dissimilar alkali metals such as sodium and potassium, which have similar properties to lithium, cause reduction of lithium storage sites and inhibition of diffusion. Therefore, it is preferable that the HTO contains no alkali metal other than lithium.
  • the detection amount of alkali metals other than lithium, such as sodium and potassium, in ICP emission spectroscopy is less than the lower limit of quantification.
  • Example 1 Synthesis of lithium titanate Titanium dioxide (crystal form: anatase, specific surface area: 270 m 2 /g) 1 g, lithium hydroxide monohydrate (purity 99% or more, manufactured by Kojundo Chemical Co., Ltd.) 10 g, and distilled water 50 mL are mixed to have an internal volume. It was sealed in a 100 mL hydrothermal synthesis container with a fluororesin liner. This was placed in a constant temperature bath, the temperature was raised from room temperature to 180° C. in 1 hour, and then kept for 24 hours for hydrothermal synthesis. After completion of the synthesis, the mixture was naturally cooled to room temperature in a constant temperature bath.
  • the sample was taken out together with the solution from the hydrothermal synthesis container, and the solid content was separated and collected by suction filtration using a membrane filter (pore size: 0.2 ⁇ m).
  • the recovered solid content was once dispersed in ion-exchanged water using an ultrasonic cleaner, and again suction-filtered using a membrane filter.
  • the solid content recovered by suction filtration was dried overnight in a dryer at 70°C.
  • Thermogravimetric measurement of the sample A′′ was performed by the following procedure to determine the chemical composition of the sample A′′ (FIG. 5). First, in order to remove the adsorbed water, the sample A′′ was held for 12 hours at a temperature of 150° C. in a dry air atmosphere, and it was confirmed that there was no change in weight. The weight at this time was taken as the weight of titanium oxide. From the result of thermogravimetric analysis, the sample A′′ contained 3.5 wt% of adsorbed water.
  • Sample A′′ showed a pattern as shown in FIG. 6 in the powder XRD measurement.
  • a broad peak is shown in general, but the solid peaks shown in Patent Document 2 and Non-Patent Document 2 are shown. It coincided with the peak position of the HTO derived from the phase method.
  • the peak intensities of the (110) plane and the (020) plane were significantly smaller than those of the HTO derived from the solid phase method in the sample A′′. It is thought that this is due to the nano-ization of the HTO.
  • Sample A′′ was used as an active material, acetylene black was used as a conductive agent, and polytetrafluoroethylene was used as a binder so that the weight ratio of active material:conductive agent:binder was 5:5:1. It was produced and dried in a vacuum of 10 Pa or less for 12 hours at a temperature of 150° C. The weight of the active material is obtained by subtracting 3.5 wt% of adsorbed water contained in the sample A′′.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • the electrochemical lithium insertion/desorption behavior of this lithium secondary battery was measured.
  • a lithium insertion/desorption test (apparatus used: HJ-SD8, manufactured by Hokuto Denko (the same applies below)) was performed electrochemically at a temperature of 25° C., a current density of 10 mA/g, and a cutoff potential of 3.0 V to 1.0 V. It was FIG. 9 shows the voltage change of this lithium secondary battery due to lithium insertion/desorption, and Table 1 shows the charge/discharge capacity.
  • the graph shown in FIG. 9 has a voltage flat portion in the vicinity of 1.3 V to 2 V, and it has been revealed that a reversible lithium insertion/elimination reaction is possible.
  • the initial insertion amount of the sample A′′ per weight of the active material was 318 mAh/g, which was higher than that of TiO 2 (B) or HTO derived from the solid phase method.
  • the initial desorption of the sample A′′ was performed.
  • the amount was 283 mAh/g
  • the initial charge/discharge efficiency was 89%, which was higher than the initial charge/discharge efficiency of 50% of TiO 2 (B), which was almost the same as the initial charge/discharge efficiency of HTO derived from the solid phase method.
  • the active material containing titanium oxide of the present invention is capable of highly reversible lithium insertion/elimination reaction superior to the active material containing TiO 2 (B) and the active material containing HTO derived from the solid phase method. is there. It has been revealed that the active material containing the titanium oxide of the present invention is promising as an electrode material for a lithium secondary battery.
  • Example 2 A heat-treated lithium titanate sample B was obtained in the same manner as in the synthesis of lithium titanate of Example 1 except that the mass of titanium dioxide was changed to 2 g.
  • the pattern of the powder XRD measurement result of the sample B (FIG. 10) is similar to the pattern of the powder XRD measurement result of the sample A, and the sample B has a monoclinic crystal structure compounded in the rock salt type crystal structure. It was found to be Li 2 TiO 3 with structure.
  • Sample B was subjected to lithium/proton exchange in the same manner as in Example 1 and fired in a vacuum of 10 Pa or less at a temperature of 400° C. for 5 hours to obtain HTO sample B′′-1.
  • the pattern of the powder XRD measurement result of the sample B′′-1 (FIG. 11) is similar to the pattern of the powder XRD measurement result of the sample A′′, and it was confirmed that the sample B′′-1 was HTO.
  • the ratio I 1 /I 0 of the peak height I 1 of the peak near 25° and the peak height I 0 of the peak near 28° shown in Sample B′′-1 was 0.4.
  • the initial insertion amount per weight of the active material of Sample B′′-1 was 320 mAh/g
  • the initial desorption amount was 277 mAh/g
  • the initial charge/discharge efficiency was 87%.
  • the capacity retention rate of the cycle was almost 100%, and even in the 10th cycle, Sample B′′-1 maintained the discharge capacity of 271 mAh/g.
  • Example 3 An HTO sample B′′-2 was obtained by the same method as in the production of the titanium oxide of Example 1, except that the heat treatment after lithium/proton exchange was performed for 5 hours at a temperature of 400° C. in air.
  • the pattern of the powder XRD measurement result of the sample B′′-2 (FIG. 12 )
  • a plurality of peaks attributable to anatase were confirmed (arrow shown in FIG. 12 ). ..
  • the ratio I 1 /I 0 of the peak height I 1 of the peak around 25° and the peak height I 0 of around 28° shown by the sample B′′-2 was 2.5. Further, as shown in Table 1, the initial insertion amount per weight of the active material of Sample B′′-2 was 294 mAh/g, the initial desorption amount was 268 mAh/g, and the initial charge/discharge efficiency was 91%. It was The capacity retention rate in the initial cycle was almost 100%. Further, even in the 10th cycle, the sample B′′-2 maintained the discharge capacity of 264 mAh/g.
  • Example 4 Lithium titanate of Example 1 except that 10 g of lithium hydroxide monohydrate was changed to 5 g of lithium hydroxide monohydrate and 20 g of sodium hydroxide (purity 97% or more, manufactured by Wako Pure Chemical Industries).
  • Sample C which was heat-treated lithium titanate, was obtained by the same method as in the synthesis of.
  • the pattern of the powder XRD measurement result of the sample C (FIG. 13) is similar to the pattern of the powder XRD measurement result of the sample A.
  • the monoclinic crystal structure is compounded in the rock salt type crystal structure. It was found to be Li 2 TiO 3 with structure.
  • Sample C was subjected to lithium/proton exchange in the same manner as in Example 1 and baked at 400° C. for 5 hours in a vacuum of 10 Pa or less to obtain HTO sample C′′.
  • Powder CRD measurement result of sample C′′ (FIG. 14) is similar to the pattern of the powder XRD measurement result of the sample A′′, and it was confirmed that the sample C′′ was HTO.
  • the ratio I 1 /I 0 of the peak height I 1 of the peak near 25° and the peak height I 0 of the peak near 28° shown by the sample C′′ was 0.9.
  • the initial insertion amount per weight of the active material of Sample C′′ was 311 mAh/g
  • the initial desorption amount was 269 mAh/g
  • the initial charge/discharge efficiency was 86%.
  • the capacity retention rate in the initial cycle was almost 100%. Further, even in the 10th cycle, the sample C′′ maintained the discharge capacity of 270 mAh/g.
  • Example 5 Except for changing the process of once dispersing the recovered solid content in ion-exchanged water using an ultrasonic cleaner to the process of temporarily dispersing it in 0.05 mol/L hydrochloric acid using an ultrasonic cleaner, Sample D, which was heat-treated lithium titanate, was obtained in the same manner as in the synthesis of lithium titanate of Example 1.
  • the pattern of the powder XRD measurement result of the sample D (FIG. 15) is similar to the pattern of the powder XRD measurement result of the sample A.
  • the monoclinic crystal structure is compounded in the rock salt type crystal structure. It was found to be Li 2 TiO 3 with structure.
  • the sample D was subjected to lithium/proton exchange in the same manner as in Example 1 and baked at a temperature of 400° C. for 5 hours in a vacuum of 10 Pa or less to obtain an HTO sample D′′.
  • the pattern of the powder XRD measurement result of the sample D′′ (FIG. 16) was similar to the pattern of the powder XRD measurement result of the sample A′′, and it was confirmed that the sample D′′ was HTO. As shown in FIG. The ratio I 1 /I 0 of the peak height I 1 of the peak near 25° and the peak height I 0 of the peak near 28° indicated by the sample D′′ was 0.6. Further, from Table 1, the initial insertion amount per weight of the active material of Sample D′′ was 309 mAh/g, the initial desorption amount was 277 mAh/g, and the initial charge/discharge efficiency was 86%. The capacity retention rate was almost 100%, and Sample D′′ maintained a discharge capacity of 274 mAh/g even in the 10th cycle.
  • Example 6 A method similar to the synthesis of lithium titanate of Example 1 except that the recovered solid content was once dispersed in ion-exchanged water using an ultrasonic cleaner and the process of suction filtration using a membrane filter again was omitted.
  • a heat-treated lithium titanate sample E was obtained.
  • Sample E was subjected to lithium/proton exchange in the same manner as in Example 1 to obtain sample E′ which was a lithium titanate proton exchanger.
  • Sample E′-1 was obtained by baking sample E′ in air at a temperature of 280° C. for 5 hours.
  • Sample E′′-1 was obtained by baking sample E′ at a temperature of 400° C. in a vacuum of 10 Pa or less for 5 hours.
  • Got 2 The patterns of the powder XRD measurement results of the sample E′′-1 and the sample E′′-2 (FIG. 18 and FIG. 19, respectively) were confirmed in addition to the pattern of the powder XRD measurement result of the sample A′′, and a plurality of peaks attributable to anatase were confirmed. It was done (arrow).
  • Example 7 Sample E was dispersed in an ethanol solution of polyethylene glycol and evaporated to dryness, which was then heated in air at a temperature of 300° C. for 1 hour, and further calcined at a temperature of 600° C. for 1 hour in an argon atmosphere to give carbon on the surface. A sample to which was attached was prepared. Thereafter, in the same manner as in Example 5, a heat-treated lithium titanate sample F having carbon on the surface thereof was obtained as a sample F. Sample F was a black powder, and carbon was not released even when immersed in an aqueous solution.
  • the pattern of the powder XRD measurement result of the sample F (FIG. 20) is similar to the pattern of the powder XRD measurement result of the sample A, and the central part of the sample F has a monoclinic crystal structure in the rock salt type crystal structure. It was found to be Li 2 TiO 3 with a modified structure.
  • Sample F was subjected to lithium/proton exchange in the same manner as in Example 1 and baked in a vacuum of 10 Pa or less at a temperature of 450° C. for 5 hours to obtain a sample F′′ which is an HTO having carbon on the surface.
  • Sample F′′ The pattern of the powder XRD measurement result of Sample A′′ (FIG. 21) was similar to the pattern of the powder XRD measurement result of Sample A′′.
  • the ratio I 1 /I 0 of the peak heights I 0 of the peaks was 0.7.
  • the sample F′′ was heat-treated at 800° C. in an argon atmosphere to be completely dehydrated, and then thermogravimetric analysis was performed in air. It was confirmed that there was a weight loss of 0.5 wt% and carbon was attached to the sample F′′.
  • Sample G was subjected to lithium/proton exchange in the same manner as in Example 1 to obtain sample G′ which is a lithium titanate proton exchanger.
  • the pattern of the powder XRD measurement result of the sample G′ (FIG. 23) was similar to the pattern of the powder XRD measurement result of the sample A′.
  • Sample G′ was fired in air at a temperature of 280° C. for 5 hours to obtain HTO sample G′′.
  • the pattern of the powder XRD measurement result of sample G′′ (FIG. 24) is that of sample E′′-1.
  • the intensity of a plurality of peaks (arrows) attributable to anatase was strong. As shown in FIG.
  • the ratio I 1 /I 0 between the peak height I 1 of the peak and the peak height I 0 of the peak near 28° was 7.8.
  • the initial insertion amount per unit weight of the active material of Sample G′′ was 309 mAh/g
  • the initial desorption amount was 261 mAh/g
  • the initial charge/discharge efficiency was 85%.
  • the capacity retention rate was 98%, and even in the 10th cycle, Sample G′′ maintained a discharge capacity of 249 mAh/g.
  • Comparative example 2 Na 2 Ti 3 O 7 was synthesized by the method of Patent Document 1. This Na 2 Ti 3 O 7 was wet pulverized at 500 rpm for 5 hours using a planetary ball mill (P-6 type manufactured by Fritsche). The pulverized sample was heat-treated in air at a temperature of 700° C. for 10 hours to obtain a heat-treated sodium titanate sample H. Sample H was immersed in 0.5 mol/L hydrochloric acid for 3 days at a temperature of 60° C., and the hydrochloric acid was replaced every other day for sodium/proton exchange to obtain sample H′ which was a proton exchanger of sodium titanate. .. Sample H′ was fired in air at a temperature of 260° C.
  • HTO sample H′′ shows the pattern of the powder XRD measurement result of HTO. It was As a result of chemical analysis of Sample H′′ by ICP emission spectroscopy, it was confirmed that 0.045 wt% (450 ppm) of sodium remained. Further, when the primary particles were examined by FE-SEM, Isotropic particles, anisotropic particles, and amorphous particles were mixed, and the average particle size was 345 nm.
  • a high-value-added material can be manufactured by using a low-priced raw material without requiring a special device.
  • INDUSTRIAL APPLICABILITY The titanium oxide of the present invention has a high capacity and has an extremely high practical value as an electrode material for a lithium secondary battery having excellent initial charge/discharge efficiency and cycle characteristics.
  • the lithium secondary battery in which the titanium oxide of the present invention is applied to an electrode material as an active material can be expected to have a high capacity, is capable of reversible lithium insertion/desorption reactions, and is excellent in long-term charge/discharge cycles. There is.

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Abstract

L'invention concerne un oxyde de titane qui est représenté par la formule générale H2Ti12O25 et dans lequel la quantité détectée de métaux alcalins autres que le lithium est inférieure à la limite inférieure de mesure, telle qu'analysée au moyen d'une spectroscopie d'émission ICP. Le procédé de production d'un oxyde de titane comprend : une étape de synthèse d'un titanate de lithium ; une étape de traitement thermique du titanate de lithium ; une étape d'échange de lithium/protons ; et une étape de traitement thermique d'un échangeur de protons. Dans l'étape de synthèse de titanate de lithium, un composé de titane, dans une matière première de titane contenant un composé de titane, et un composé de lithium, dans une matière première de lithium contenant un composé de lithium, sont soumis à une cristallogenèse et un titanate de lithium est obtenu. Dans l'étape de traitement thermique, le titanate de lithium obtenu à partir de l'étape de synthèse du titanate de lithium, est traité thermiquement. Dans l'étape d'échange de lithium/protons, le lithium dans le titanate de lithium traité thermiquement, obtenu à partir de l'étape de traitement thermique, est échangé avec des protons. Dans l'étape de traitement thermique d'un échangeur de protons, l'échangeur de protons de titanate de lithium obtenu à partir de l'étape d'échange de lithium/protons est traité thermiquement à une température de 200 à 600° C
PCT/JP2020/002158 2019-01-23 2020-01-22 Oxyde de titane, procédé de production d'oxyde de titane et batterie rechargeable au lithium utilisant un matériau actif d'électrode contenant de l'oxyde de titane WO2020153409A1 (fr)

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CN102910671A (zh) * 2011-08-05 2013-02-06 微宏新材料(湖州)有限公司 锂离子电池负极活性材料的制备方法
JP2014051425A (ja) * 2012-09-10 2014-03-20 National Institute Of Advanced Industrial & Technology チタン酸化物単結晶粒子及びその製造方法、並びに該チタン酸化物単結晶粒子を含む電極活物質、該電極活物質を用いてなる蓄電デバイス
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