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
  • H01M4/362—Composites
  • H01M4/366—Composites as layered products
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
  • H01M10/0562—Solid materials
• • 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
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0407—Methods of deposition of the material by coating on an electrolyte layer
• • 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
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0421—Methods of deposition of the material involving vapour deposition
  • H01M4/0428—Chemical vapour deposition
• • 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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • 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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • 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
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
  • H01M4/381—Alkaline or alkaline earth metals elements
  • H01M4/382—Lithium
• • 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
• • 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
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • 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
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • 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
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/028—Positive 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
  • H01M4/52—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 an active material and a method for producing the same.
• Batteries comprising a positive electrode, a negative electrode, and an electrolyte have a high energy density and can be easily reduced in size and weight, so they are widely used as power sources for portable electronic devices such as notebook computers and mobile phones.
• Examples of the active material contained in the positive electrode of such a battery include lithium metal composite oxides having a layered crystal structure such as LiCoO 2 , LiNiO 2 and LiMnO 2 , lithium manganese oxide having a spinel structure (LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 ), etc. are known.
• Patent Documents 1 and 2 In recent years, for the purpose of improving battery performance, techniques for forming a coating on the active material have been proposed (see Patent Documents 1 and 2 and Non-Patent Document 1, for example).
• an object of the present invention is to provide an active material capable of obtaining excellent battery performance and a method for producing the same.
• the present invention provides an active material having a core portion and a coating portion located on the surface of the core portion,
• the core portion contains a lithium (Li) element, a manganese (Mn) element and an oxygen (O) element
• the coating portion contains an element A (A is at least one selected from the group consisting of Ti, Zr, Ta, Nb and Al) and an oxygen (O) element
• T lithium
• Mn manganese
• O oxygen
• W % by mass
• W Provided is an active material in which the value of /(S ⁇ T) is greater than 0 and equal to or less than 15% by mass/(cm 3 /g).
• the present invention provides an active material having a core portion and a coating portion located on the surface of the core portion,
• the core portion contains a lithium (Li) element, a manganese (Mn) element and an oxygen (O) element
• the coating includes an element A (A is at least one of Ti, Zr, Ta, Nb and Al) and an oxygen (O) element, providing an active material, wherein, in a spectrum obtained by line analysis from the surface to the inside of the active material by the STEM method on a cross section of the active material, the half width of the peak of the element A in the spectrum is 25 nm or less. It is.
• a element A is at least one of Ti, Zr, Ta, Nb and Al on the surface of the core portion containing lithium (Li) element, manganese (Mn) element and oxygen (O) element by atomic deposition method ) and an oxygen (O) element.
• the active material of the present invention has a core portion and a covering portion.
• the covering portion is located on the surface of the core portion. Each of the core portion and the covering portion will be described below.
• the core portion is a portion that occupies most of the active material and serves as the base material of the active material.
• the core portion may contain, for example, a lithium metal composite oxide.
• a known lithium metal composite oxide can be used as the lithium metal composite oxide.
• a lithium-containing composite oxide having a layered rock salt structure represented by the general formula LiMO 2 (M is a metal element) a lithium-containing composite oxide having a spinel structure represented by the general formula LiM 2 O 4
• LiMSiO 4 LiMSiO 4
• the core portion preferably contains a spinel-type composite oxide containing lithium (Li) element, manganese (Mn) element and oxygen (O) element (hereinafter, when this core portion is referred to as “core portion A" there is.).
• core portion A a spinel-type composite oxide containing lithium (Li) element, manganese (Mn) element and oxygen (O) element
• the active material of the present invention containing the core portion A has an operating potential of 4.5 V or more based on metal Li. "Having a working potential of 4.5 V or more at a metal Li reference potential” does not necessarily have only a working potential of 4.5 V or more as a plateau region, and partially has a working potential of 4.5 V or more. It is meant to include even if it is.
• the active material of the present invention is not limited to a positive electrode active material consisting only of a 5V-class positive electrode active material having an operating potential of 4.5 V or more in the plateau region.
• an active material of the present invention may include a positive electrode active material having a working potential of less than 4.5V as the plateau region.
• the 5V-class positive electrode active material preferably accounts for 30% by mass or more, preferably 50% by mass or more, and particularly preferably 80% by mass or more (including 100% by mass). Substances are allowed.
• Elements other than the lithium (Li) element, the manganese (Mn) element, and the oxygen (O) element contained in the core portion A may be one kind or two or more kinds.
• at least one element is preferably one selected from the group consisting of Ni, Co and Fe (hereinafter referred to as "M1 element").
• the M1 element is a substitution element that mainly contributes to developing an operating potential of 3.0 V or higher with respect to the metal Li reference potential.
• the other elements consist of Na, Mg, Al, P, K, Ca, Ti, V, Cr, Fe, Co, Cu, Ga, Y, Zr, Nb, Mo, In, Ta, W, Re and Ce.
• the M2 element is preferably an M2 element consisting of one or a combination of two or more selected from the group.
• the M2 element is a substitution element that mainly contributes to stabilizing the crystal structure and enhancing the properties. By selecting the M2 element from the above elements, it is possible to improve the capacity retention rate.
• the M1 and M2 elements contained in the structure are different elemental species.
• spinel-type lithium manganese having a crystal structure in which part of the Mn sites in LiMn 2 O 4- ⁇ is substituted with Li, M1 element, and another M2 element.
• Those containing contained complex oxides can be mentioned.
• formula (1) Li x (M 1 y M 2 z Mn 2-xyz )O 4- ⁇
• formula (2) general formula [Li x (Ni y M 3 z Mn 3-xyz )O 4- ⁇ ], and a spinel-type lithium-manganese-containing composite oxide.
• the M3 elements in formula ( 2 ) are Na, Mg, Al, P, K, Ca, Ti, V, Cr, Fe, Co, Cu, Ga, Y, Zr, Nb, Mo, In, It is preferably one or a combination of two or more selected from the group consisting of Ta, W, Re and Ce.
• x is 1.00 or more and 1.20 or less
• y is 0.20 or more and 1.20 or less
• z is 0.001 or more and 0.400 The following are preferable.
• x is 1.00 or more and 1.20 or less
• y is 0.20 or more and 0.70 or less
• z is greater than 0 and 0.20. It is preferably 5 or less.
• 4- ⁇ indicates that oxygen deficiency may be included, and ⁇ is preferably 0 or more and 0.2 or less.
• spinel-type composite oxides examples include LiMn 2 O 4 , Li 4 Mn 5 O 12 (Li 1.333 Mn 1.667 O 4 ) and Li 2 Mn 4 O 9 (Li 0.667 O 4 ), which are lithium manganese oxides . 889 Mn 1.778 O 4 ) and LiNi x Mn 2-x O 4 (x represents a number greater than 0 and less than 2), which is a lithium manganese nickel oxide.
• Other descriptions of the core part can be the same as those described in, for example, WO2017/150504A1, so descriptions thereof are omitted here.
• the core portion is preferably a particle composed of a lithium-nickel metal composite oxide having a layered structure containing Li, Mn and O (hereinafter, this core portion is also referred to as “core portion B”).
• the core portion may optionally include M4 element (wherein M4 is one or more elements selected from the group consisting of Ni, Co and Al, or Ni, Co and one or more elements selected from the group consisting of Al, a transition metal element present between Group 3 elements to Group 11 elements of the periodic table, and the first period of the periodic table any one or a combination of two or more elements in the group consisting of typical metal elements from to the third period.).
• the active material of the present invention may contain other components in addition to the core portion B. However, from the viewpoint that the properties of the core portion B can be effectively obtained, the core portion B can account for 80% by mass or more, especially 90% by mass or more, and among them 95% by mass or more (including 100% by mass). preferable.
• the core portion B is preferably particles made of a lithium metal composite oxide having a layered structure represented by the formula (3): Li 1+x M 4 1-x O 2 .
• "1+x" is preferably 0.95 or more and 1.09 or less.
• core part A and the core part B can be the same as those described in, for example, WO2017/150504A1 and JP6626434B2, so descriptions thereof are omitted here.
• the covering portion is arranged on the surface of the core portion and covers the surface of the core portion.
• the covering part evenly covers the surface of the core part, or partially covers the surface of the core part so that the surface of the core part is partially exposed.
• the covering portion evenly covers the surface of the core portion and that the surface of the core portion is not exposed as much as possible.
• the covering part is arranged on the surface of the core part for the purpose of not degrading the performance of the core part during use of the battery incorporating the active material of the present invention.
• the core portion contains A element (A is at least one selected from the group consisting of Ti, Zr, Ta, Nb and Al) and oxygen (O) element. .
• a element is at least one selected from the group consisting of Ti, Zr, Ta, Nb and Al
• oxygen (O) element oxygen
• the manganese element that constitutes the active material tends to be easily eluted into the electrolytic solution in the form of ions.
• Mn ions When Mn ions are eluted into the electrolyte, Mn may be deposited on the negative electrode, resulting in deterioration of battery performance.
• a resistance layer may be formed at the interface between the active material and the solid electrolyte when the battery is charged and discharged. When such a resistance layer is formed, lithium ions cannot be transferred smoothly, and as a result, the battery performance may deteriorate.
• the present inventor studied an active material in which a coating portion containing an A element and an oxygen element is provided on the surface of a core portion containing a lithium (Li) element, a manganese (Mn) element, and an oxygen (O) element. repeated.
• a coating portion containing an A element and an oxygen element is provided on the surface of a core portion containing a lithium (Li) element, a manganese (Mn) element, and an oxygen (O) element. repeated.
• Li lithium
• Mn manganese
• O oxygen
• the average thickness of the coating portion is T (nm)
• the specific surface area of the active material is S (m 2 /g)
• the A element contained in the coating portion When the amount of is W (% by mass), as described later, by providing an active material having a value of W/(T ⁇ S) greater than 0 and 15% by mass/(cm 3 /g), the above-mentioned I found that the problem of is solved.
• the action of the coating effectively suppresses the elution of manganese contained in the core into the electrolyte. .
• the active material of the present invention when used in, for example, a solid battery containing a solid electrolyte, the action of the coating makes it difficult to form a resistive layer at the interface between the active material and the solid electrolyte, and lithium ions are transferred to the core. is inserted and removed smoothly.
• the coating contains at least one element A selected from the group consisting of Ti, Zr, Ta, Nb and Al.
• the A element may be one kind, or a combination of two or more kinds.
• the coating may be one or more oxides of the A element.
• the coating may be a composite oxide of two or more elements or an oxide of each element.
• the covering portion is an oxide of the A element, the abundance ratio of the A element and the oxygen element in the covering portion is preferably a stoichiometric ratio such that an oxide of the A element is formed.
• the covering portion may contain a lithium (Li) element in addition to the A element and the oxygen element.
• the covering portion may be a composite oxide of lithium element and A element.
• the coating is a composite oxide of the lithium element and the A element, the proportions of the lithium element, the A element and the oxygen element in the coating are stoichiometric so that a composite oxide of the lithium element and the A element is formed. A ratio is preferred.
• the coating portion may contain elements other than the A element, the oxygen element, and the Li element.
• the covering portion cover the surface of the core portion as thinly and densely as possible from the viewpoint of effectively preventing deterioration of the performance of the core portion while allowing the core portion to exhibit its inherent performance.
• T the average thickness of the coating portion
• S the specific surface area of the active material
• W the amount of element A contained in the coating portion
• the covering portion means the density of the covering portion per 1 g of the core portion.
• Conventionally there has been known a technique of coating the surface of particles of an active material to prevent deterioration of the performance of the active material.
• the coating portion is not dense, the deterioration of the performance of the active material cannot be effectively suppressed.
• the covering portion since the covering portion thinly and densely covers the surface of the core portion, the performance inherent in the core portion is not reduced. , the deterioration of the performance of the core portion can be effectively prevented by the covering portion.
• the value of W/(S ⁇ T) is 0.1% by mass/(cm 3 /g) or more. 0% by mass/(cm 3 /g) or less, more preferably 1.0% by mass/(cm 3 /g) or more and 8.0% by mass/(cm 3 /g) or less .
• the average thickness T (nm) is the average value of the thickness of the coating portion of each active material particle.
• the average thickness T (nm) can be measured, for example, with a scanning transmission electron microscope (STEM). If necessary, energy dispersive X-ray spectroscopy (EDS) can be combined for analysis and measurement. Specifically, line analysis is performed on the surface portion of the active material, and the peak width of the A element can be measured as the thickness of the coating portion from the result. Note that the line analysis can be performed in the same manner as the measurement of the half-value width, which will be described later. Also, the average thickness T (nm) can be the average value when the surface portion of the active material is measured at 10 points by the above method.
• STEM scanning transmission electron microscope
• EDS energy dispersive X-ray spectroscopy
• the amount W (% by mass) of the A element is the average value of the amount of the A element in each active material particle.
• the amount W (% by mass) of the A element is determined by measuring the amount of the A element by ICP emission spectrometry and subtracting the amount of the A element in the core portion.
• the specific surface area S (m 2 /g) is measured for a powder that is an aggregate of active material particles.
• the specific surface area S (m 2 /g) was measured using a flow-type gas adsorption method specific surface area measuring device, and after replacing the inside of the glass cell for 5 minutes while flowing nitrogen gas at a gas amount of 30 mL / min, nitrogen gas Pretreatment is performed in an atmosphere at 250° C. for 10 minutes, and then measured by the BET one-point method.
• the covering portion have an average thickness T of 50 nm or less, since the function of the core portion as an active material is less likely to be hindered by the covering portion, and the core portion can sufficiently perform as an active material.
• the average thickness T of the covering portion is more preferably 40 nm or less, even more preferably 35 nm or less, and even more preferably 30 nm or less and 25 nm or less.
• the average thickness T of the covering portion is 0.1 nm or more because it is possible to effectively prevent deterioration of the performance of the active material.
• the average thickness T of the covering portion is more preferably 1.0 nm or more, even more preferably 3.0 nm or more, and more preferably 5.0 nm or more. More preferred.
• the amount W of the A element is preferably 0.001% by mass or more and 2.000% by mass or less from the viewpoint of not interfering with the capacity and rate characteristics of the core portion. From the viewpoint of making this advantage more remarkable, the amount W of element A is more preferably 0.01% by mass or more and 1.0% by mass or less, and more preferably 0.01% by mass or more and 0.5% by mass or less. is more preferable.
• the specific surface area S is preferably 0.1 m 2 /g or more and 2.0 m 2 /g or less from the viewpoint of improving the capacity and rate characteristics of the core portion. From the viewpoint of making this advantage more remarkable, the specific surface area S is, for example, more preferably 0.2 m 2 /g or more, and even more preferably 0.3 m 2 /g or more. On the other hand, the specific surface area S is, for example, more preferably 1.5 m 2 /g or less, and even more preferably 1.0 m 2 /g or less.
• the coating portion in the active material of the present invention preferably covers the surface of the core portion as thinly and densely as possible. It can be evaluated by a spectrum obtained by line analysis from the surface to the inside of the substance. Specifically, the half-value width of the peak of the A element in the spectrum correlates with the thickness and density of the coating portion, and the half-value width of 25 nm or less reduces the inherent performance of the core portion. It is preferable from the viewpoint that the covering portion can effectively prevent deterioration in performance of the core portion. From this point of view, the half width is more preferably 20 nm or less, and even more preferably 16 nm or less.
• the half width is preferably 0.005 nm or more, more preferably 0.05 nm or more, more preferably 0.5 nm or more, from the viewpoint of effectively preventing performance deterioration of the core portion by the coating portion. is more preferably 3.0 nm or more, and even more preferably 5.0 nm or more.
• the half-value width of at least one type of A element may be the above-mentioned value or less, and the half-value width of all the A elements is the above-mentioned value. is preferably less than or equal to
• the half width is measured by the following method.
• An energy dispersive X-ray spectrometer (EDS) is used to measure the average intensity profile of the A element in the coating. Measurement conditions by EDS are as follows. An active material powder is embedded in a resin, and a focused ion beam is used to prepare a TEM-observable thin sample. A scanning transmission electron microscope (STEM) attached to EDS is used to observe the vicinity of the surface of the active material, and mapping data of element A is obtained by EDS for a region including the coating portion. From the obtained elemental mapping data, an average intensity line profile of element A, which is a component of the covering portion, is extracted. The equipment used in this measurement is shown below.
• STEM JEM-ARM200F (manufactured by JEOL Ltd.)
• EDS JED-2300T Dry SD100GV (manufactured by JEOL Ltd.)
• EDS analysis software NSS Ver4.1 (manufactured by Thermo Fisher Scientific) Acquisition conditions for elemental mapping data Accelerating voltage: 200 kV, magnification: 2,000,000 times, STEM image acquisition detector: ADF STEM image acquisition resolution: 512 ⁇ 512 pixels, EDS mapping resolution: 256 ⁇ 256 pixels (The magnification and measurement time are adjusted as appropriate so that the mapping data of the A element in the covered portion can be obtained.) ⁇ Acquisition contents of average intensity profile From the obtained elemental mapping data, the net intensity excluding the background from the area (about 70 to 90 nm) including the active material and the entire coating layer in the vertical direction with a width of about 50 nm in the horizontal direction with respect to the flat active material surface A line profile (for 100 points) is extracted for the A element.
• the covering part only needs to exist so as to cover the surface of the core part. Therefore, the covering portion may cover the entire surface of the core portion, or may cover a portion of the surface of the core portion.
• the coverage of the covering portion with respect to the entire surface of the core portion is, for example, preferably 60% or more, more preferably 70% or more, particularly preferably 80% or more, further preferably 90% or more.
• the coverage of the coated portion can be determined by, for example, a method of observing the surface of the active material by combining a scanning transmission electron microscope (STEM) and, if necessary, an energy dispersive X-ray spectroscopy (EDS), or an Auger electron spectroscopic analysis method. can be confirmed by
• the shape of the active material of the present invention is not particularly limited, it may be particulate, for example.
• the particle size of the active material of the present invention is expressed as a volume cumulative particle size D50 (hereinafter also referred to as "average particle size") at a cumulative volume of 50% by volume measured by a laser diffraction scattering particle size distribution measurement method, for example 0. It is preferably 0.5 ⁇ m or more, preferably 1.0 ⁇ m or more, preferably 2.0 ⁇ m or more, and preferably 2.5 ⁇ m or more. This is because excessive agglomeration of particles is suppressed and dispersibility is improved.
• the volume cumulative particle diameter D50 is, for example, preferably 20.0 ⁇ m or less, more preferably 15.0 ⁇ m or less, and particularly preferably 10.0 ⁇ m or less. This is because the contact between the active material particles and the contact between the active material particles and the solid electrolyte particles can be sufficiently ensured.
• the volume cumulative particle diameter D50 has a meaning as a substitute value for the average diameter of particles including primary particles and secondary particles.
• Primary particles means the smallest unit particles surrounded by grain boundaries when observed with a SEM (scanning electron microscope, eg, 500-5000 times).
• the active material of the present invention means primary particles unless otherwise specified.
• secondary particles means particles that are agglomerated so that a plurality of primary particles share a part of their outer peripheries (grain boundaries) and that are independent of other particles. .
• the volume cumulative particle size D50 is measured by the following method. Using an automatic sample feeder for a laser diffraction particle size distribution analyzer (“Microtrac SDC” manufactured by Microtrac Bell Co., Ltd.), the active material powder was mixed with 20% by mass ethanol solvent and 0.1% by mass hexametaphosphoric acid. After being put into the solvent and irradiated with 40 W ultrasonic waves for 90 seconds at a flow rate of 40%, the particle size distribution was measured using a laser diffraction particle size distribution analyzer “MT3000II” manufactured by Microtrack Bell Co., Ltd. The volume cumulative particle size D50 is measured from the volume-based particle size distribution chart.
• the water-soluble solvent when measuring D50 is passed through a 60 ⁇ m filter, the “solvent refractive index” is 1.33, the particle permeability condition is “transmission”, the measurement range is 0.243 ⁇ m or more and 704.0 ⁇ m or less, the measurement time was 30 seconds, and the average value of two measurements was taken as D50 .
• the active material of the present invention it is advantageous for the active material of the present invention to have its moisture content adjusted within a certain range. Specifically, if the moisture content of the active material is too high, the interfacial resistance between the active material and the solid electrolyte may increase.
• the active material of the present invention has a moisture content (mass ppm) up to 300 ° C. measured by the Karl Fischer method, for example, may be 600 ppm or less, may be 550 ppm or less, or may be 500 ppm or less. good. Also, the moisture content may be 10 ppm or more, 50 ppm or more, 100 ppm or more, or 200 ppm or more. It is preferable that the amount of water contained in the active material is as small as possible in order to reduce structural deterioration of the active material due to reaction with lithium and to reduce reaction with the electrolyte during battery operation. In order to minimize the amount of water contained in the active material, the active material may be dried in an inert atmosphere at a temperature such as 300° C.
• the procedure for measuring the moisture content by the Karl Fischer method is as follows. That is, using a Karl Fischer moisture meter, the measurement sample is heated to 110 ° C., the released moisture content (mass ppm) is measured, and then the measurement sample is heated to 300 ° C., the released moisture content (mass ppm) was measured, and the value obtained by adding each was taken as the moisture content.
• the measurement is performed in a nitrogen atmosphere, and CA-100 (manufactured by Mitsubishi Chemical Corporation) is used as a measuring device, for example.
• the coating portion is formed by an atomic deposition method (hereinafter also referred to as “ALD”).
• the manufacturing method of the core is not particularly limited, and a composite oxide containing lithium (Li) element, manganese (Mn) element and oxygen (O) element may be manufactured by a conventionally known method.
• a composite oxide can be obtained by using lithium carbonate powder and manganese oxide powder (for example, manganese dioxide powder) as raw materials, mixing them to obtain a mixed powder, and firing the mixed powder.
• the core portion is obtained by pulverizing the composite oxide thus obtained to adjust the particle size to a desired size.
• a covering portion is formed by ALD on the surface of the core portion thus obtained.
• ALD is theoretically capable of forming a coating by one atomic layer, so that a thin and dense coating can be formed.
• a sol-gel method is conceivable, but it is not easy to form a thin and dense covering portion with the sol-gel method.
• the coating can be formed as follows. First, a first step of putting the core portion into a reaction chamber, a second step of heating the reaction chamber to remove water adhering to the core portion, and heating the inside of the reaction chamber to a film formation temperature. a third step of adding a precursor material of the coating portion; a fourth step of adding an oxidizing agent into the chamber; a fifth step of removing excess precursor material and reaction products in the gas phase; and a sixth step of adding an oxidizing agent into the chamber.
• an inert gas into the reaction chamber to form a fluidized bed.
• Nitrogen or argon, for example, can be used as the inert gas.
• the flow rate of the inert gas (N 2 , Ar) can be set within a range of, for example, 10 cm 3 /min or more and 100 L/min or less.
• the heating temperature in the second step can be set, for example, within the range of 100°C or higher and 200°C or lower.
• the heating time at this time can be in the range of, for example, 1 hour or more and 12 hours or less.
• the heating temperature in the third step is not particularly limited as long as it is a temperature at which the covering portion can be formed.
• Precursor substances include, for example, organoaluminum compounds such as trimethylaluminum (hereinafter also referred to as “TMA”).
• TMA trimethylaluminum
• heated precursor material may be added into the reaction chamber.
• the temperature for heating the precursor substance can be set to, for example, room temperature or higher and 300° C. or lower.
• the third step is preferably performed until the precursor substance is chemically adsorbed on the surface of the core portion to form a single phase.
• the oxidizing agent used in the fourth step include H2O , O3 , H2O2 , H2 plasma, O2 plasma, Ar plasma, N2O plasma and the like.
• excess precursor substances and reaction products can be removed, for example by purging.
• reaction products include methane gas.
• the core portion is exposed to the oxidizing agent to react with the single phase of the precursor material, and the desired coating portion can be formed by this reaction.
• the oxidizing agent the same oxidizing agent as used in the fourth step can be used.
• a thin and dense covering portion can be successfully formed. It is preferable to repeat the first to sixth steps so that the amount of element A contained in the coated portion is, for example, in the range of 10 ppm or more and 50,000 ppm or less.
• the precursors used in the present invention include Zr(NEtMe) 4 , ZrI 4 , ZrCp 2 Me 2 , ZrCp 2 Me 2 , ZrCp 2 Me(OMe), ZrCp 2 Cl 2 , ZrCp ( NMe2 ) 3 , ZrCl4 , Zr[N( SiMe3 ) 2 ] 2Cl2 , Zr(thd) 4 , Zr ( NEt2 ) 4 , Zr( OtBu ) 4 , Zr( OtBu ) 2 (dmae) 2 , Zr(O i Pr) 4 , Zr(O i Pr) 2 (dmae) 2 , Zr(NEtMe) 4 , Zr(NEtMe) 3 (guan-NEtMe), Zr(NEtMe) 2 (guan- NEtMe) 2 , Zr(MeCp)(TM
• the A element is Al, AlMe 3 , AlMe2O i Pr, AlMe 2 H, AlMe 2 Cl, AlMe2(C 3 H 6 NMe 2 ), AlH 3 N: (C 5 H 11 ), AlEt 3 , AlCl3, AlBu3, Al2( NMe2 ) 6 , Al( OsBu ) 3 , Al( OnPr ) 3 , Al(OEt) 3 , Al( NMe2 ) 3 , Al ( NiPr2 ) 3 , Al( NiPr2 ) 2 ( C3H6NMe2 ), Al( NEt2 ) 3 , Al ( NEt2 ) 2 ( C3H6NMe2 ), Al ( mmp ) 3 , Al( i PrAMD) Et2 , Al( CH3 ) 3 .
• the A element is Ti, Tb(thd) 3 , Ti(Cp)CHT, Ti( CpMe )(OiPr) 3 , Ti(CpMe 5 )(OMe) 3 , Ti(EtCp)(NMe 2 ) 3 , Ti(NEt 2 ) 4 , Ti(NEtMe) 3 (guan-NEtMe), Ti(NEtMe) 4 , Ti(NMe 2 ) 3 (CpMe), Ti(NMe 2 ) 3 (CpN), Ti( NMe2 ) 3 (dmap), Ti( NMe2 ) 4 , Ti(NMeEt) 4 , Ti(Np) 4 , Ti(OEt) 4 , Ti(OiPr) 2 ( dmae ) 2 , Ti( OiPr ) 2 (NMe 2 ) 2 , Ti(O i Pr) 2 (thd) 2 , Ti(O i Pr) 3 ( i
• the A element is Ta, Ta(NEt) ( NEt2 ) 3 , Ta( NEt2 ) 3NtBu , Ta( NEt2 ) 5 , Ta(NEtMe) 2 ( NiPr ), Ta (NEtMe) 5 , Ta( NiPr )(NEtMe) 2 , Ta( NMe2 ) 3 ( CMe2Et ), Ta( NMe2 ) 5 , Ta(NtAm) (NMe2)3 , Ta (N tAm )[( NMe2 )] 3 , Ta( NtBu )( iPrAMD ) 2 ( NMe2 ), Ta( NtBu )( NEt2 ) 3 , Ta( NtBu ) ( tBu2pz ) 3 , Ta(OEt) 4 (dmae), Ta(OEt) 5 , TaBr 5 , TaCl 5 , TaCp(N t Bu)
• Nb(N t Bu)(NEt 2 ) 3 , Nb(N t Bu)(NEtMe) 3 , Nb(OEt) 5 , NbCl 5 and NbF 5 can be used.
• a precursor substance containing Li may be used in the above-described ALD.
• the precursor containing Li include LiO t Bu, LiOSiMe 3 , LiN(SiMe 3 ) 2 , Li(thd), Li(N(SiMe 3 ) 2 ) and the like.
• the active material of the present invention thus obtained can be used, for example, in the form of an electrode mixture containing the active material and an electrolyte.
• the electrolyte may be either solid or liquid.
• the content of the active material in the electrode mixture may be 30% by mass or more, or 40% by mass or more when the total solid content is 100% by mass. It may be 50% by mass or more.
• the content of the active material may be, for example, 98% by mass or less, 90% by mass or less, or 85% by mass or less. When the content of the active material is within the above range, the function as an electrode can be sufficiently exhibited.
• the solid electrolyte that can be used in the present invention can be the same as solid electrolytes that are used in general solid batteries. Examples thereof include sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, halide solid electrolytes, etc. Among them, sulfide solid electrolytes are preferred.
• the sulfide solid electrolyte may contain, for example, lithium (Li) element and sulfur (S) element and have lithium ion conductivity, or lithium (Li) element, phosphorus (P) element and sulfur ( It may contain S) element and have lithium ion conductivity.
• the sulfide solid electrolyte may be any of crystalline material, glass-ceramics, and glass.
• the sulfide solid electrolyte may have a crystal phase with an aldirodite structure.
• sulfide solid electrolytes include Li 2 SP 2 S 5 , Li 2 SP 2 S 5 -LiX ("X" represents one or more halogen elements), Li 2 S -P2S5 - P2O5 , Li2S - Li3PO4 - P2S5 , Li3PS4 , Li4P2S6 , Li10GeP2S12 , Li3.25Ge0 _ _ .25P0.75S4 , Li7P3S11 , Li3.25P0.95S4 , LiaPSbXc ( X is at least one halogen element, a is 3.0 represents a number of 6.0 or less, b represents a number of 3.5 or more and 4.8 or less, and c represents a number of 0.1 or more and 3.0 or less.
• Other examples include sulfide solid electrolytes described in WO2013/0998
• the electrolytic solution that can be used in the present invention can be the same electrolytic solution that is used in general liquid-based batteries.
• an organic electrolytic solution, a polymer solid electrolyte, a molten salt, or the like can be used.
• organic electrolytes include solvents such as propylene carbonate, ethylene carbonate (EC), butylene carbonate, diethyl carbonate, dimethyl carbonate, methylethyl carbonate, ⁇ -butyrolactone (GBL), esters such as tetrahydrofuran, 2- substituted tetrahydrofuran such as methyltetrahydrofuran; ethers such as dioxolane, diethyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane; dimethylsulfoxide, sulfolane, methylsulfolane, acetonitrile, methyl formate, methyl acetate;
• a mixed solvent of two or more kinds can
• electrolyte salts that dissolve in organic solvents include lithium perchlorate, lithium borofluoride, lithium hexafluorophosphate (hereinafter referred to as “LiPF 6 ”), lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, halogen and lithium salts such as lithium chloride and lithium aluminate chloride.
• the active material contained in the electrode mixture may be the active material of the present invention alone, or may be a combination of the active material of the present invention and other active materials.
• Other active materials include particles made of known lithium-transition metal composite oxides.
• the active material of the present invention is contained in an amount of 50% by mass or more, particularly 70% by mass or more, based on the total active material.
• the electrode mixture may contain other materials such as conductive aids and binders as necessary.
• An electrode layer such as a positive electrode layer can be prepared by mixing an electrode mixture and a solvent to prepare a paste, applying the paste on a current collector such as an aluminum foil, and drying the paste.
• an electrode layer can be produced by solid-phase mixing the materials of an active material, a solid electrolyte, and a conductive aid, and molding the mixture into a pellet.
• the active material of the present invention can be suitably used as a positive electrode active material for batteries.
• the battery may be a primary battery or a secondary battery.
• the battery of the present invention can have, for example, a positive electrode layer, a negative electrode layer, and an electrolyte layer containing an electrolytic solution disposed between the positive electrode layer and the negative electrode layer.
• the positive electrode layer contains the active material of the present invention.
• the active material of the present invention can be suitably used for solid batteries, particularly solid lithium batteries. Among them, it can be suitably used for secondary batteries, particularly solid lithium secondary batteries. Examples of the shape of the battery include laminate type, cylindrical type, square type, coin type, and the like.
• a solid battery preferably has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer positioned between them, and the positive electrode layer contains the active material of the present invention described above.
• a solid battery can be produced, for example, by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer in this order and then press-molding them.
• Solid battery means a solid battery that does not contain any liquid or gel material as an electrolyte, or a solid battery that contains, for example, 50% by mass or less, 30% by mass or less, or 10% by mass or less of liquid or gel material as an electrolyte. Aspects are also included.
• the negative electrode active material used for the negative electrode layer can be the same as the negative electrode active material used for general solid batteries.
• Specific negative electrode active materials that can be used include materials that occlude and release lithium ions, such as carbon materials, silicon, silicon oxide compounds such as Si—O, tin compounds, and known materials such as lithium titanate.
• Examples of the carbon material include sintered organic polymer compounds such as polyacrylonitrile, phenolic resin, phenolic novolak resin, cellulose, artificial graphite, and natural graphite.
• the negative electrode layer can be produced in the same manner as the positive electrode layer, except that such a negative electrode active material is used.
• Example 1 (1) Preparation of Core Portion A spinel-type lithium-manganese-nickel-containing composite oxide (hereinafter also referred to as “LMNO”) was prepared as a core portion.
• LMNO spinel-type lithium-manganese-nickel-containing composite oxide
• Mn 41.7% by mass
• Ni 13.3% by mass
• Ti 5.3% by mass.
• a coating portion containing the element A and the element oxygen was formed on the surface of the core portion by ALD.
• the elements shown in Table 1 below were used.
• Tris(dimethylamino)cyclopentadienyl zirconium (ZrCp(NMe 2 ) 3 ) was used as the precursor material containing the A element.
• a fluidized bed was formed in the reaction chamber at a flow rate of 50 cm 3 /min using nitrogen as an inert gas.
• the inside of the reaction chamber was set at a film-forming temperature of 350° C., and the precursor substance was introduced, and water was used as the oxidizing agent to form a film so that the amount of Zr was 150 ppm.
• the desired active material was obtained.
• Example 2 An active material was obtained in the same manner as in Example 1, except that the Zr content was changed to 600 ppm (Example 2) and the Zr content was changed to 900 ppm (Example 3).
• Example 4 An active material was obtained in the same manner as in Example 1 except that the precursor material was tetrakis(dimethylamino)zirconium (ZrTDMA) and the amount of Zr was 1500 ppm.
• ZrTDMA tetrakis(dimethylamino)zirconium
• Example 1 In Example 1, no covering portion was formed. An active material was obtained in the same manner as in Example 1 except for this.
• [Battery assembly] 8.0 g of the active material powder obtained in Examples and Comparative Examples and 1.0 g of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were weighed and mixed in a mortar for 10 minutes. After that, a mixture of the active material powder and acetylene black was added to 8.3 g of a solution of 12% by mass of PVdF (manufactured by Kishida Chemical Co., Ltd.) in N-methylpyrrolidone (NMP) and further mixed. After that, 5 mL of NMP was added and thoroughly mixed to prepare a paste. This paste was applied onto an aluminum foil as a current collector.
• NMP N-methylpyrrolidone
• the paste was applied using an applicator adjusted to a gap of 100 ⁇ m to 280 ⁇ m.
• the coating film of the paste was vacuum-dried at 140° C. overnight. After that, it was roll-pressed so that the linear pressure was 0.3 t/cm 2 .
• a circle with a diameter of 16 mm was punched out of aluminum foil and used as a positive electrode.
• the positive electrode was vacuum-dried at 200° C. for 300 minutes or more to remove adhering moisture, and then incorporated into the battery. Further, the average value of the mass of the aluminum foils with a diameter of 16 mm was determined in advance, and the mass of the positive electrode mixture was determined by subtracting the mass of the aluminum foil from the mass of the positive electrode.
• the content of the active material was obtained from the mixing ratio of the active material, acetylene black and PVdF.
• a metal Li foil with a diameter of 19 mm and a thickness of 0.5 mm was used as the negative electrode.
• the electrolytic solution was prepared by dissolving 1 mol/L of LiPF 6 as a solute in a solvent obtained by volume-mixing ethylene carbonate and dimethyl carbonate at a ratio of 3:7.
• An electrochemical evaluation cell was produced using the above positive electrode, negative electrode, and electrolytic solution.
• the active materials obtained in each example are superior in rate characteristics to the active materials of the comparative examples.
• the reason for this is thought to be that the active material obtained in each example has a low interfacial resistance on its surface.
• the active material obtained in each example is superior in cycle characteristics to the active material of the comparative example.
• the reason for this is thought to be that the active material obtained in each example suppresses the elution of manganese during the charging and discharging process of the battery.
• an active material capable of obtaining excellent battery performance and a method for producing the same are provided.

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