Method for preparing complex oxides

Abstract

To reduce the variation in the shape of the crystals produced. [Solution] A solution containing each raw material is produced in an environment with a lower oxygen concentration than the atmosphere, and oxygen A solution containing each raw material is mixed in a low-concentration environment to produce a mixed solution, and this mixed solution is used Composite oxides are prepared using a hydrothermal method.

Description

Technical Field

[0001] The present invention relates to a composite oxide. The present invention also relates to a power storage device.

Background Art

[0002] In recent years, the development of power storage devices such as lithium-ion secondary batteries has been advanced.

[0003] As the above power storage device, for example, a power storage device having an electrode using LiFePO4 (lithium iron phosphate), which is a composite oxide, as an active material can be mentioned. A power storage device having an electrode using LiFePO4 has high thermal stability and good cycle characteristics.

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Prior Art Documents

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Patent Documents

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[0014] [Figure 1] [Figure 2] [Figure 3] [Figure 4] [Figure 5] [Figure 6] [Figure 7] [Figure 8] [Figure 9]

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[0026] <00001 [Patent Document 1] Japanese Patent Publication No. 2004-95385 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, when LiFePO4 is produced by the conventional hydrothermal method, the LiFePO4 crystals There was a problem with significant variation in shape.

[0009] If there is a large variation in crystal shape, for example, the packing density of crystals in the active material of the electrode will be low. This can lead to a decrease in the charge and discharge characteristics of the energy storage device. Therefore, it is necessary to suppress the decrease in the charge and discharge characteristics of the energy storage device. To control this, it is necessary to control the crystal shape and make the crystal shape uniform in the active material of the electrode. preferable.

[0010] One aspect of the present invention aims to reduce the variation in crystal shape produced by the hydrothermal method. It will be one of the options. [Means for solving the problem]

[0011] In one aspect of the present invention, a mixed solution containing raw materials is produced in an environment with a lower oxygen concentration than that of the atmosphere, By producing a complex oxide using a mixed solution via a hydrothermal method, the resulting complex oxide To suppress variations in crystal shape.

[0012] One aspect of the present invention relates to a compound containing Li (lithium) in an atmosphere with a lower oxygen concentration than that of the atmosphere. Using this method to produce a solution containing Li, and under an atmosphere with a lower oxygen concentration than air, P (phosphorus) Forming a solution containing P using a compound containing P, and in an atmosphere with a lower oxygen concentration than air. And one of the following: Fe (iron), Co (cobalt), Ni (nickel), and Mn (manganese). Using one or more compounds containing a transition metal, one or Forming a solution containing one or more transition metals including Fe, Co, Ni, and Mn, and Mixing a solution containing Li and a solution containing P in an atmosphere with a lower oxygen concentration than the atmosphere to form a solution containing Li and P, and Mixing the solution containing Li and P and the solution containing the transition metal in an atmosphere with a lower oxygen concentration than the atmosphere To form a mixed solution, and hydrothermally using the mixed solution To produce a composite oxide represented by the general formula LiMPO4 (M is one or more of Fe, Co, Ni, and Mn). This is a method for producing a composite oxide.

Advantages of the Invention

[0013] According to one aspect of the present invention, the shape of the produced crystal can be controlled. Therefore, the variation in crystal form Can be reduced.

Brief Description of the Drawings

[0014] [Figure 1] A flowchart for explaining an example of a method for producing a composite oxide. [Figure 2] A schematic diagram showing an example of the crystal structure of a composite oxide. [Figure 3] A diagram for explaining an example of an electric storage device. [Figure 4] A diagram for explaining an example of the structure of an electrode in an electric storage device. [Figure 5] A diagram for explaining an example of an electric storage device. [Figure 6] A diagram for explaining an example of an electric device. [Figure 7] A diagram and its block diagram for explaining an example of an electric device. [Figure 8] A diagram showing the observation result of LiFePO4 by a scanning electron microscope. [Figure 9] A diagram showing the observation result of LiFePO4 of a comparative example by a scanning electron microscope. [Modes for carrying out the invention]

[0015] Examples of embodiments for illustrating the present invention will be described below with reference to the drawings. Modifying the contents of the embodiments without departing from the spirit of the invention and the scope of the present invention is permitted. This is easy for a professional. Therefore, the present invention is not limited to the embodiments described below. do not have.

[0016] Furthermore, the contents of each embodiment can be combined with each other as appropriate. The contents can be substituted for each other as appropriate.

[0017] Furthermore, ordinal numbers such as 1st, 2nd, etc. are added to avoid confusion of the constituent elements. Therefore, each The number of constituent elements is not limited to the number of ordinal numbers.

[0018] (Embodiment 1) In this embodiment, an example of a composite oxide having crystals will be described.

[0019] An example of a composite oxide production method in this embodiment will be explained using the flowchart in Figure 1. I will reveal it.

[0020] In this embodiment, as shown in Figure 1(A), step S 11. The mixed solution used when synthesizing complex oxides is in a place with a lower oxygen concentration than the atmosphere. It is produced under an atmosphere (also called a low-oxygen atmosphere). Furthermore, as step S12, the product is produced A complex oxide is produced from the mixed solution by a hydrothermal method.

[0021] Furthermore, for details of an example of a composite oxide production method, please refer to the flowchart in Figure 1(B). explain.

[0022] In one example of the production method for composite oxides in this embodiment, as shown in Figure 1(B), step As S11_1, weigh out a compound containing Li (lithium) (also called a lithium compound). Also, as step S11_2, a compound containing P (phosphorus) (also called a phosphorus compound) is used. Weigh the ). Also, in step S11_3, a compound containing a transition metal (transition metal compound) To weigh (also called an object).

[0023] Examples of lithium compounds include lithium hydroxide monohydrate (LiOH·H2O) and anhydrous water. Lithium oxide (LiOH), lithium carbonate (Li2CO3), lithium oxide (Li2O) By using lithium nitrate (LiNO3) or lithium acetate (CH3COOLi), etc. It is possible.

[0024] Examples of phosphorus compounds include phosphoric acid (e.g., orthophosphoric acid (H3PO4)) or phosphorus Ammonium hydrogen oxyhydrogen (e.g., ammonium dihydrogen phosphate (NH4H2PO4), etc.) You can use it.

[0025] Examples of transition metal compounds include Fe (iron), Co (cobalt), Ni (nickel), and M One or more compounds containing any of the n (manganese) elements can be used. For example, salt Iron chloride tetrahydrate (FeCl2·4H2O), iron sulfate heptahydrate (FeSO4·7H2O), vinegar Iron acid (Fe(CH3COO)2), manganese chloride tetrahydrate (MnCl2·4H2O), sulfur Manganese acid hydrate (MnSO4·H2O), manganese acetate tetrahydrate (Mn(CH3CO3) Cobalt chloride hexahydrate (CoCl2·6H2O), cobalt sulfate ( CoSO4), cobalt acetate tetrahydrate (Co(CH3COO)2·4H2O), nickel chloride Kell hexahydrate (NiCl2·6H2O), nickel sulfate hexahydrate (NiSO4·6H2O) ), or use nickel acetate tetrahydrate (Ni(CH3COO)2·4H2O), etc. It is possible.

[0026] Next, in step S12_1, the lithium compound is dissolved in an atmosphere with a lower oxygen concentration than that of the atmosphere. It dissolves in a medium to produce a solution containing Li (also called a lithium-containing solution). As P12_2, a phosphorus compound is dissolved in a solvent under an atmosphere with a lower oxygen concentration than that of the atmosphere, and P is obtained. A solution containing (also called a phosphorus-containing solution) is produced. Also, as step S12_3, air is used A transition metal compound is dissolved in a solvent under an atmosphere of low oxygen concentration to create a solution containing the transition metal (transition It produces a metal-containing solution (also known as a metal-containing solution).

[0027] For example, water can be used as a solvent for dissolving lithium compounds, phosphorus compounds, or transition metal compounds. These can be used. Furthermore, the oxygen concentration in the solvent should preferably be 4.5 ppm or less. For example, by performing nitrogen bubbling in the solvent, the oxygen concentration in the solvent can be reduced. This can be done by reducing the oxygen concentration in the solvent, thereby suppressing the oxidation of the resulting substance. It is possible.

[0028] Furthermore, an atmosphere with a lower oxygen concentration than the atmosphere is, for example, a nitrogen atmosphere, or a mixture of nitrogen and hydrogen. You can use things like a suitable atmosphere.

[0029] Next, in step S13, the solution containing Li and the solution containing P are subjected to an oxygen concentration from the atmosphere. Mixing under low temperature conditions produces a solution containing Li and P (also called a lithium-phosphorus solution). It is generated. At this time, the solution containing Li and P becomes weakly alkaline.

[0030] Next, as step S14, the solution containing Li and P and the solution containing the transition metal are exposed to the air. The mixture is prepared by mixing under an atmosphere with a lower oxygen concentration.

[0031] At this time, for example, while stirring the solution containing the transition metal, a small amount of the solution containing Li and P is added dropwise. It is preferable to lower the temperature. This allows the transition to occur more easily than the reaction between the transition metal ion and the hydroxide ion. Hydrogen ions in metal-containing solutions and hydroxide ions in solutions containing Li and P The neutralization reaction with is preferentially carried out. Therefore, the formation of unwanted transition metal hydroxides is suppressed. It is possible.

[0032] Next, in step S15, a composite oxide is produced using the mixed solution by a hydrothermal method.

[0033] For example, the mixed solution is placed in a pressure-resistant container and subjected to pressurization and heating, and then cooled. A complex oxide can be produced by filtering the resulting solution.

[0034] For example, an autoclave can be used as a pressure-resistant vessel.

[0035] Furthermore, the temperature during processing by pressurization and heating should be, for example, above 100°C and below the critical temperature of water. It is preferable that this is the case. Furthermore, the pressure used when performing the processing by pressurization and heating is, for example, 0.1 It is preferable that the pressure is above MPa and below the critical pressure of water. Furthermore, processing by pressurization and heating is performed. The time is preferably, for example, 0.5 hours or more. Also, the pressure vessel should be kept more acidic than the atmosphere. By creating an atmosphere with a low elementary concentration, the hydrothermal method can be performed in an atmosphere with a lower oxygen concentration than the atmosphere. Processing can be performed. For example, in a pressure vessel under a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen. It is preferable to do this. This makes it possible to remove unwanted oxygen from the pressure vessel, Furthermore, even if the solution oxidizes during the process, it can be reduced, thus preventing oxidation. The effects of this can be mitigated.

[0036] Alternatively, a reducing agent may be added and the mixture may be treated under pressure and heat. For example, reducing The agent can also be added before processing by pressurization and heating. Furthermore, the process is not limited to this. For example, a reducing agent may be added to a solution containing a transition metal, and then a mixed solution may be produced.

[0037] Examples of reducing agents include ascorbic acid, sulfur dioxide, sulfurous acid, sodium sulfite, and sulfurous acid. Sodium oxyhydrogen, ammonium sulfite, or phosphorous acid can be used. By using this agent, even if the solution oxidizes during the process, it can be reduced. Therefore, the effects of oxidation can be reduced.

[0038] The composite oxide obtained by the hydrothermal method has multiple crystals. Furthermore, the crystals of the above composite oxide The crystal shape is a rectangular parallelepiped 161, as shown in Figure 2, for example. Furthermore, multiple rectangular parallelepiped crystals are formed. The variation in crystal shape within each crystal is small. This is because oxidation is suppressed. This is because the impurities in the fabricated composite oxide were reduced. The structure is preferably of the olivine type.

[0039] The above is a description of an example of a method for producing composite oxides in this embodiment.

[0040] As explained using Figures 1 and 2, an example of a composite oxide production method in this embodiment. So, what happens when you put a solution containing Li (lithium) and P (phosphorus) into an atmosphere with a lower oxygen concentration than the atmosphere? By mixing the solutions containing Li and P, a solution containing Li and P is produced, and then the oxygen concentration is lowered from the atmosphere. Mix the solution containing Li and P with the solution containing the transition metal under a low-temperature atmosphere. By generating a solution, the formation of by-products due to oxidation can be suppressed. Therefore, This method can reduce variations in the crystal shape of composite oxides produced using the hydrothermal method.

[0041] (Embodiment 2) In this embodiment, an energy storage device is provided that includes an electrode using the composite oxide shown in Embodiment 1 as the active material. Let's explain an example.

[0042] An example of the structure of the energy storage device in this embodiment will be explained with reference to Figure 3.

[0043] The energy storage device shown in Figure 3 comprises a positive electrode 201, a negative electrode 202, an electrolyte 203, and a separator 20 Includes 4.

[0044] The positive electrode 201 comprises a positive electrode current collector 211 and a positive electrode active material layer 212.

[0045] For the positive electrode current collector 211, for example, aluminum, copper, nickel, or titanium can be used. It is possible to use an alloy made of multiple materials applicable to the positive electrode current collector 211. It may also be used as the electrical element 211.

[0046] For the positive electrode active material layer 212, for example, the composite oxide described in Embodiment 1 can be used. In this case, for example, a composite oxide can be produced using the production method shown in Embodiment 1. Furthermore, in this process, the composite oxide functions as an active material.

[0047] For example, by adding a conductive additive, a binder, and a solvent to the composite oxide in Embodiment 1 above... This generates a paste. Furthermore, the paste is applied to the positive electrode current collector 211 and baked. By doing so, a positive electrode active material layer 212 can be fabricated.

[0048] The negative electrode 202 comprises a negative electrode current collector 221 and a negative electrode active material layer 222.

[0049] For example, iron, copper, or nickel can be used as the negative electrode current collector 221. Furthermore, an alloy using multiple materials applicable to the negative electrode current collector 221 is used for the negative electrode current collector 221. That's good too.

[0050] For example, silicon or graphite can be used for the negative electrode active material layer 222. Silicon or graphite functions as the active material.

[0051] Furthermore, the negative electrode active material layer 222 may have a structure having, for example, multiple whiskers.

[0052] Furthermore, graphene can be used as the negative electrode active material layer 222, for example.

[0053] Graphene has voids that allow ions to pass through, and sp 2 A single layer of carbon atoms containing a bond A single sheet composed of these elements, or a laminate in which two to 100 such sheets are stacked together. This refers to (also called multilayer graphene). It also refers to a network of graphene. Also called graphene. Note that graphene contains elements other than carbon at a concentration of 30 atomic percent or less, or 15 atomic percent. The following elements other than carbon and hydrogen may also be included. Therefore, graphene analogs are also graphene. It is included in Fen.

[0054] Graphene is characterized by its high conductivity, flexibility, mechanical strength, and heat resistance. It has [a certain characteristic]. Furthermore, graphene has a capacity to store ions.

[0055] For example, when using silicon or graphite as the active material, the silicon or graphite is replaced with graphene. It may be further coated. Also, for example in the case of multilayer graphene, a layer may be placed between the multiple graphene layers. It may contain fine particles such as ricin or graphite.

[0056] By using graphene, the conductivity of the electrode can be increased. Therefore, graphene It can also function as a binder. Furthermore, by using graphene, It is also possible to construct electrodes without using conventional conductive additives or binders.

[0057] Furthermore, by using graphene, deformation and fracture of the electrodes can be suppressed.

[0058] Furthermore, graphene may be used in the positive electrode active material layer 212, not limited to the negative electrode active material layer 222. For example, the multiple crystals in the composite oxide in Embodiment 1 above are made of graphene It may also be coated. Furthermore, for example, in the case of multilayer graphene, a composite acid may be used between the multiple graphene layers. It may contain microparticles of the monstrous substance.

[0059] Here, as an example of the negative electrode active material layer 222, a negative electrode active material having a structure with multiple whiskers is described. An example of the structure of the negative electrode 202 including layer 222 is shown in Figure 4(A).

[0060] The electrode shown in Figure 4(A) has a negative electrode current collector 221 and a negative electrode active material layer 222, and the negative electrode active The material layer 222 includes a layer 251 having whiskers.

[0061] For example, silicon can be used as the layer 251 having whiskers.

[0062] Furthermore, in the layer 251 having whiskers, the core of the whisker is crystalline, and the core It is preferable that the peripheral portion is amorphous. For example, the amorphous portion is used for ion storage and The volume change associated with release is minimal. Furthermore, the crystalline portion exhibits both electrical and ionic conductivity. Because of its high efficiency, it can increase the rate at which ions are stored and released.

[0063] Furthermore, for example, whiskers can be removed using the LPCVD (Low Pressure CVD) method. A layer 251 having the above characteristics can be formed.

[0064] For example, if layer 251 having whiskers is silicon, LPCVD (Low Press When forming layer 251 with whiskers using the CVD method, the source gas is used. In this case, a silicon-containing depositional gas can be used. For example, silicon hydride, silicon fluoride, or silicon chloride can be used. Cut.

[0065] Furthermore, the pressure should be between 10 Pa and 1000 Pa, preferably between 20 Pa and 200 Pa. It is preferable to do so. Furthermore, by adjusting the pressure, the crystalline portion and the amorphous portion can be separated. It is possible to differentiate between different aspects of quality.

[0066] Furthermore, a layer containing graphene is provided to cover the layer 251 having whiskers, thus forming the negative electrode. An active material layer 222 can also be constructed. A graph can be used to cover the layer having whiskers. Regarding the structural example of a negative electrode 202 including a negative electrode active material layer 222 having a layer with an element, This is shown in Figure 4(B).

[0067] The electrode shown in Figure 4(B) has a graphene layer 252 in addition to the structure shown in Figure 4(A). include.

[0068] The graphene layer 252 is provided in contact with the whisker layer 251.

[0069] For example, a graphene oxide layer is formed on a layer 251 having whiskers, and then heat treatment is performed. By reducing the graphene oxide layer, a layer 252 containing graphene can be formed. can.

[0070] As shown in Figure 4(B) as an example, graphene is placed in contact with the layer containing whiskers. By providing a layer having such properties to constitute the negative electrode active material layer, for example, when storing and releasing ions Even if the volume of the layer containing whiskers changes, the layer containing graphene will not react to the change in volume. To mitigate the effects of stress, the fracture of the whisker structure in the whisker-containing layer is controlled. This can be prevented. Therefore, the cycle characteristics of the energy storage device can be improved.

[0071] Furthermore, the separator 204 shown in Figure 3 can be, for example, paper, nonwoven fabric, glass fiber, or synthetic Fibers can be used, and synthetic fibers include, for example, nylon (polyamide) and vinyl. Ron (also called Binalon) (polyvinyl alcohol-based fiber), polyester, acrylic, Polyolefin or polyurethane can be used. Also, separator 204 Examples include fluorinated polymers, polyethers (e.g., polyethylene oxide or polypropylene) (e.g., benzene oxides), polyolefins (e.g., polyethylene or polypropylene), Polyacrylonitrile, polyvinylidene chloride, polymethyl methacrylate, polymethyl Crylate, polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, Polyvinylpyrrolidone, polyethyleneimine, polybutadiene, polystyrene, polyiso polymer materials such as polymers and polyurethanes, derivatives of said polymer materials, and cells such as paper and membranes. One type selected from rose-based materials and nonwoven fabrics, either alone or in combination of two or more types, can be used. It can be. Also, the material that makes up the separator 204 is dissolved in the electrolyte 203. It is preferable to use materials that do not dissolve.

[0072] Electrolyte 203 may be, for example, a material containing carrier ions or a carrier ion Materials that allow for the movement of particles can be used, for example, lithium chloride (LiCl), fluoride Lithium (LiF), lithium perchlorate (LiClO4), and lithium borofluoride (LiB) One or more of F4 can be used. Also, lithium hexafluoride phosphate (Li PF6), lithium arsenate hexafluoride (LiAsF6), lithium trifluoromethanesulfonate Lithium (LiCF3SO3), Lithium bis(trifluoromethanesulfonyl)imide (L iN(SO2CF3)2), Lithium bis(pentafluoroethanesulfonyl)imide ( Lithium salt materials containing fluorine, such as LiN(SO2C2F5)2), are used as electrolyte 203. It can also be used.

[0073] Furthermore, the above materials can be mixed with a solvent to constitute electrolyte 203. As for the solvent, For example, cyclic carbonates (e.g., ethylene carbonate (EC), propylene carbonate) Polyethylene carbonate (PC), butylene carbonate (BC), or vinylene carbonate (VC), etc. ), acyclic carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate) Dehydrated methyl carbonate (DEC), ethyl methyl carbonate (hereinafter abbreviated as EMC), methyl propyl carbonate - Carbonate (MPC), isobutyl methyl carbonate, or dipropyl carbonate ( DPCs, etc., aliphatic carboxylic acid esters (e.g., methyl formate, methyl acetate, propyl carboxylate) Methyl ionate or ethyl propionate, etc.), γ-lactones (e.g., γ-butyrolac) (e.g., ton), acyclic ethers (e.g., 1,2-dimethoxyethane (DME), 1,2- Diethoxyethane (DEE), or ethoxymethoxyethane (EME), etc., cyclic ether Tel compounds (e.g., tetrahydrofuran or 2-methyltetrahydrofuran), or ammonium compounds. Kill phosphate esters (e.g., dimethyl sulfoxide, 1,3-dioxolane, triphosphate) Examples include methyl phosphate, triethyl phosphate, or trioctyl phosphate, or their fluorides. These can be used in combination, one or more of them.

[0074] Furthermore, as an example of an energy storage device in this embodiment, regarding the structure of a coin-type secondary battery... Let's explain using Figure 5.

[0075] The energy storage device shown in Figure 5 comprises a positive electrode 301, a negative electrode 302, a separator 304, and a housing 305. , housing 306, ring-shaped insulator 307, spacer 308, washer 309, It holds.

[0076] Positive electrode 301 corresponds to positive electrode 201 in Figure 3, for example. In this case, positive electrode current collector 311 This corresponds to the positive electrode current collector 211, and the positive electrode active material layer 312 corresponds to the positive electrode active material layer 212. .

[0077] The negative electrode 302 corresponds to, for example, the negative electrode 202 in Figure 3. In this case, the negative electrode current collector 321 This corresponds to the negative electrode current collector 221, and the negative electrode active material layer 322 corresponds to the negative electrode active material layer 222. .

[0078] Separator 304 corresponds to separator 204 in Figure 3, for example.

[0079] The housing 305, housing 306, spacer 308, and washer 309 are made of, for example, metal (e.g. For example, it is preferable that it be made of stainless steel. Housings 305 and 306 are made of positive electrode 301 Each of the negative electrodes 302 also has the function of electrically connecting to the outside.

[0080] The energy storage device shown in Figure 5 has a positive electrode 301, a negative electrode 302, and a separator 304 impregnated in an electrolyte solution. Then, with the bottom of the housing 306 facing downwards, the negative electrode 302, separator 304, and ring-shaped insulator 30 7. The positive electrode 301, spacer 308, washer 309, and housing 305 are stacked in order, housing The 305 and the casing 306 are crimped together to create a coin-type rechargeable battery.

[0081] The above is a description of an example of an energy storage device in this embodiment.

[0082] Furthermore, the above-mentioned practical application is not limited to coin-type rechargeable batteries, but also applies to, for example, prismatic or cylindrical rechargeable batteries. The composite oxide in application method 1 can be applied.

[0083] As explained with reference to Figures 3 to 5, in an example of the energy storage device in this embodiment, By using composite oxides in the application form to fabricate the positive electrode of the energy storage device, the active material is filled. Because density can be increased, the energy density of energy storage devices can be increased.

[0084] (Embodiment 3) In this embodiment, an example of an electrical device using an energy storage device will be described.

[0085] Examples of electrical equipment using energy storage devices include, for example, display devices, lighting devices, desktop or This includes notebook personal computers, image playback devices (for example, DVDs (Digital) Playback of still images or videos stored on recording media such as Versatile Disc. Devices, etc.), mobile phones, portable game consoles, portable information terminals, e-books, video cameras, etc. Digital still cameras, high-frequency heating devices (such as microwave ovens), electric rice cookers, electric washing machines. Machinery, air conditioning equipment (e.g., air conditioners), electric refrigerators, electric freezers, electric freezers. Examples include refrigerators, DNA storage freezers, and dialysis machines. Furthermore, power is supplied from energy storage devices. Mobile devices propelled by electric motors using electricity are also included in the category of electrical equipment. Examples of moving vehicles include electric vehicles and hybrid vehicles that combine an internal combustion engine and an electric motor. Examples include motorized cars (also called scooters) and electric-assist bicycles.

[0086] Examples of electrical equipment in this embodiment will be explained using Figures 6 and 7.

[0087] The display device 5000 shown in Figure 6 consists of a housing 5001, a display unit 5002, and a speaker unit 5003. It has a power storage device 5004, etc. The display device 5000 is a display device for receiving TV broadcasts. It is correct.

[0088] For example, display devices for receiving TV broadcasts, display devices for personal computers, and advertising displays. All information display devices, including display devices, are included in the display devices described herein.

[0089] The display unit 5002 may be, for example, a liquid crystal display device or a light-emitting device (for example, an organic EL element). Light-emitting device with a light-emitting element in each pixel), electrophoretic display device, DMD (Digital Microwave Display). micromirror device), PDP (Plasma Display Pa Display devices such as nel, FED (Field Emission Display) It can be used.

[0090] The energy storage device 5004 is located inside the housing 5001. For example, the energy storage device in Embodiment 2 described above can be used.

[0091] Furthermore, the display device 5000 can also receive power from the commercial power supply, and also has an energy storage device. The power stored in the 5004 can also be used. Therefore, for example, in the event of a power outage, commercial power Even when power cannot be supplied from a power source, the energy storage device 5004 can be used as a power source. This allows the display device 5000 to be driven.

[0092] The lighting device 5100 shown in Figure 6 is a stationary lighting device. The lighting device 5100 is enclosed in a housing It comprises a body 5101, a light source 5102, and an energy storage device 5103.

[0093] As the light source 5102, an artificial light source that artificially obtains light using electricity can be used. The above artificial light sources include, for example, discharge lamps (such as incandescent bulbs or fluorescent lamps) or light-emitting lamps. Examples include devices (such as light-emitting diodes or organic EL devices).

[0094] The energy storage device 5103 is located within the ceiling 5104 on which the housing 5101 and light source 5102 are installed. It is provided in the section. However, it is not limited to this, for example, a power storage device 510 inside the housing 5101 You may include option 3.

[0095] Furthermore, the lighting device 5100 can receive power from the commercial power supply, and also has a power storage device. The power stored in 5103 can also be used. Therefore, for example, in the event of a power outage, commercial power Even when power cannot be supplied from a power source, the energy storage device 5103 can be used as a power source. This allows the lighting device 5100 to be driven.

[0096] Note that Figure 6 shows a fixed lighting device 5100 installed on the ceiling 5104. However, this is not limited to the ceiling 5104, for example, the side walls 5105, floor 5106, windows 5107 A power storage device can be used in fixed lighting fixtures installed in places such as [locations omitted]. Energy storage devices can also be used in lighting equipment and other applications.

[0097] The air conditioner shown in Figure 6 consists of an indoor unit 5200 and an outdoor unit 5204. ru.

[0098] The indoor unit 5200 comprises a housing 5201, an air outlet 5202, and a power storage device 5203. Note that Figure 6 shows the case where the indoor unit 5200 is equipped with a power storage device 5203. However, it is not limited to this, and for example, an energy storage device 5203 may be provided on the outdoor unit 5204. Alternatively, both the indoor unit 5200 and the outdoor unit 5204 may be equipped with a power storage device 5203.

[0099] Air conditioners can receive power from commercial power sources and also have energy storage devices. The power stored in 5203 can also be used. In particular, the indoor unit 5200 and the outdoor unit 520 When both of the 4 are equipped with energy storage devices 5203, for example, in the event of a power outage, the commercial power supply Even if electricity supply is unavailable, the energy storage device 5203 can be used as a power source. This allows the air conditioner to run more efficiently.

[0100] Figure 6 shows an example of a split-type air conditioner consisting of an indoor unit and an outdoor unit. As shown, an air conditioner has both the indoor and outdoor unit functions in a single housing. A power storage device may be installed in the same location.

[0101] The electric refrigerator-freezer 5300 shown in Figure 6 consists of a casing 5301, a refrigerator door 5302, and a freezer compartment. It includes a door 5303 and an energy storage device 5304.

[0102] The energy storage device 5304 is installed inside the housing 5301.

[0103] Furthermore, the 5300 electric refrigerator can receive power from the commercial power supply, and also has storage The power stored in the electrical device 5304 can also be used. Therefore, for example, in the event of a power outage... Even when power cannot be supplied from the commercial power source, the energy storage device 5304 can be used as a power source. By using this, the 5300 electric refrigerator / freezer can be powered.

[0104] Other electrical appliances include high-frequency heating devices such as microwave ovens, or electric rice cookers. Air conditioning equipment requires high power in a short amount of time. Therefore, it is necessary to supplement the power that cannot be supplied by the commercial power supply. To assist in this process, a power storage device is used as an auxiliary power source, allowing the commercial power supply to be used when electrical equipment is in use. This can prevent the system from stopping.

[0105] Furthermore, during periods when electrical equipment is not in use, especially the total amount of electricity that the commercial power supplier can supply... During periods when the proportion of electricity actually used (also called the electricity usage rate) is low, storage By storing power in electrical equipment, the increase in power usage outside of the above-mentioned time period can be suppressed. It is possible. For example, in the case of the electric refrigerator 5300, when the temperature is low, the refrigerator door 530 2. At night when the freezer door 5303 is not opened or closed, power is stored in the energy storage device 5304. And as the temperature rises, the refrigerator door 5302 and the freezer door 5303 are opened and closed. During the daytime, by using the energy storage device 5304 as an auxiliary power source, the daytime power usage rate It can be kept low.

[0106] Furthermore, the electrical device shown in Figure 7 is an example of a foldable portable information terminal, and Figure 7(A) is This is a schematic diagram of the external appearance, and Figure 7(B) is a block diagram.

[0107] The electrical equipment shown in Figure 7 consists of a housing 6000a and a housing 6000b, as shown in Figure 7(A). Panel 6001a, Panel 6001b, Shaft 6002, Button 6003, Connection It includes terminal 6004 and recording medium insertion section 6005. Furthermore, the electrical equipment shown in Figure 7 is As shown in Figure 7(B), the power supply unit 6101, the wireless communication unit 6102, and the calculation unit 6103 It has an audio unit 6104 and a panel unit 6105.

[0108] Panel 6001a is installed on the housing 6000a.

[0109] Panel 6001b is provided on housing 6000b. Housing 6000b also has shaft portion 60 02 connects to enclosure 6000a.

[0110] Panels 6001a and 6001b function as display panels. For example, Panels 6001a and 6001b display different images or a continuous image. You may do so.

[0111] Furthermore, if either or both of panels 6001a and 6001b function as a touch panel It may have the ability. In this case, for example, one of panel 6001a and panel 6001b or The keyboard image is displayed on both sides, and when fingers 6, 0, 10, etc. touch the keyboard image... Further input operations may be performed. Also, the display panel and touch panel are stacked to form panel 60. 01a and panel 6001b may be configured as either or both. Also, a display circuit and an optical detector Using an input / output panel equipped with an output circuit, either panel 6001a or panel 6001b or Both can be configured.

[0112] In the electrical equipment shown in Figure 7, there is a shaft portion 6002, so for example, the housing 6000a or housing 60 Move 00b to superimpose enclosure 6000a onto enclosure 6000b, thereby folding the electrical equipment. It is possible.

[0113] Button 6003 is provided on the housing 6000b. Button 600 is provided on the housing 6000a. 3 may be provided. Also, multiple buttons 6003 are provided on housing 6000a and housing 6000b It may be provided on one or both. For example, by providing a button 6003 which is a power button. Furthermore, by pressing button 6003, it is possible to control whether or not to turn on the electrical device. Cut.

[0114] The connection terminal 6004 is provided on the housing 6000a. Note that the housing 6000b has a connection terminal 6 004 may be provided. Also, multiple connection terminals 6004 can be connected to housing 6000a and housing 600 It may be provided on one or both of 0b. For example, via connection terminal 6004, personal controller By connecting a computer to electrical equipment, a personal computer can control electrical equipment. You may rewrite the contents of the stored data.

[0115] The recording medium insertion section 6005 is provided in the housing 6000a. A media insertion section 6005 may be provided. Alternatively, multiple recording media insertion sections 6005 may be provided in the housing 600. 0a and housing 6000b may be provided in either or both. For example, a card slot may be provided in the recording medium insertion area. By inserting a card-type recording medium, data can be read from the card-type recording medium to the electrical device. Alternatively, it can write data from electrical equipment to a card-type recording medium.

[0116] Furthermore, the power supply unit 6101 has the function of controlling the supply of power to operate electrical equipment. For example, from the power supply unit 6101 to the wireless communication unit 6102, the calculation unit 6103, the voice unit 6104, Power is supplied to the panel section 6105. The power supply unit 6101 is equipped with a power storage device 6111. The energy storage device 6111 is installed inside one or both of the housings 6000a and 6000b. It can be done. As the energy storage device 6111, the energy storage device shown in Embodiment 2 above can be applied. Yes, it is possible. Furthermore, the power supply circuit that generates the power supply voltage for operating electrical equipment is the power supply unit 6101. It may also be provided in this location. In this case, the power supplied by the energy storage device 6111 is used to power the power supply circuit. A power supply voltage is generated. Alternatively, the power supply unit 6101 may be connected to a commercial power supply.

[0117] The wireless communication unit 6102 has the function of transmitting and receiving radio waves. For example, the wireless communication unit 6102 It includes an antenna, a demodulation circuit, a modulation circuit, and so on. In this case, for example, radio waves from the antenna Data is exchanged with the outside using the transmission and reception of the wireless communication unit 6102. An antenna may be installed.

[0118] The arithmetic unit 6103 includes, for example, the wireless communication unit 6102, the voice unit 6104, and the panel unit 6105. It has the function of performing calculations according to the command signals input from. For example, the calculation unit 6103 It includes a CPU, logic circuits, and memory circuits.

[0119] The audio unit 6104 has the function of controlling the input and output of sound, which is audio data. For example, audio Section 6104 includes a speaker and a microphone.

[0120] The power supply unit 6101, the wireless communication unit 6102, the calculation unit 6103, and the voice unit 6104 are, for example, It is installed inside one or both of the housings 6000a and 6000b.

[0121] Panel section 6105 consists of panel 6001a (also called panel A) and panel 6001b ( It has a function to control the operation of the panel (also called Nel B). Furthermore, panel 60 is located on panel section 6105. A drive circuit is provided to control the drive of panel 6001a and panel 6001b, and The operation of Nell 6001b may be controlled.

[0122] Furthermore, the power supply unit 6101, wireless communication unit 6102, calculation unit 6103, voice unit 6104, and A control circuit may be provided in one or more of the flannel sections 6105, and the operation may be controlled by the control circuit. Furthermore, a control circuit is provided in the calculation unit 6103, and the control circuit of the calculation unit 6103 controls the power supply unit 6 101, one or more of the wireless communication unit 6102, the voice unit 6104, and the panel unit 6105 You may control the operation.

[0123] Furthermore, the power supply unit 6101, wireless communication unit 6102, voice unit 6104, and panel unit 6105 One or more memory circuits are provided, and the data necessary for operation is stored in the memory circuits. This may be done. This can increase the operating speed.

[0124] Furthermore, the electrical equipment shown in Figure 7 can receive power from the commercial power supply, and also has an energy storage device. The power stored in unit 6111 can also be used. Therefore, for example, in the event of a power outage, commercial power can be used. Even if power cannot be supplied from the power source, the energy storage device 6111 can be used as a power source. This allows electrical devices to be driven.

[0125] By using the configuration shown in Figure 7, the electrical equipment shown in Figure 7 can be, for example, a telephone, an e-reader, or a computer. It can function as one or more personal computers and gaming machines.

[0126] The above is a description of an example of electrical equipment in this embodiment.

[0127] As explained using Figures 6 and 7, an example of electrical equipment in this embodiment is a power storage device By installing a storage device, electrical equipment can be driven by the power supplied from the storage device. Therefore, it is possible to operate electrical equipment even when there is no external power supply. It is possible. [Examples]

[0128] In this example, LiFePO4(iron phosphate) was prepared using the example preparation method shown in Embodiment 1. Let's explain lithium.

[0129] First, let's explain how to prepare LiFePO4.

[0130] In the LiFePO4 preparation method in this example, LiOH·H2O:FeCl2·4H The raw materials were weighed so that the molar ratio was 2O:NH4H2PO4=2:1:1. At this time, The amount of Fe was weighed so that its concentration was 0.2M in 100ml of water.

[0131] Next, the weighed LiOH·H2O, FeCl2·4H2O, and NH4H2PO4 Dissolve it in 30 ml of water under a nitrogen atmosphere, after nitrogen bubbling, and dissolve the Li-containing solution. A liquid, a solution containing P, and a solution containing Fe were prepared.

[0132] Next, under a nitrogen atmosphere, the solution containing Li is added dropwise to the solution containing P, and the solution containing Li and P is then prepared. It was produced. At this time, Li3PO4 precipitated in the mixed solution.

[0133] Next, under a nitrogen atmosphere, a solution containing Fe is added dropwise to a solution containing Li and P, and Li, P, and A mixed solution containing Fe was prepared. At this time, a LiFePO4 precursor precipitated in the mixed solution. They were doing it.

[0134] Next, add 10 ml of water that has been nitrogen-bubbled to the mixed solution, and increase the volume of the mixed solution to 100 ml. The volume was set to l. At this time, the oxygen concentration in the mixed solution was measured to be 4.5 ppm.

[0135] Next, transfer the mixed solution to an autoclave and heat it at 150°C while stirring under a nitrogen atmosphere. The reaction was carried out at [temperature] degrees Celsius for 15 hours. The pressure during this time was 0.4 MPa.

[0136] Next, the solution reacted in the autoclave was filtered under an air atmosphere, and the remaining compound was rinsed with pure water. The compound was washed 10 times. After washing, the compound was dried in a vacuum at a temperature of 50°C.

[0137] LiFePO4 was produced through the above process.

[0138] Furthermore, the generated LiFePO4 was observed using a scanning electron microscope (also known as SEM). The observation results are shown in Figure 8.

[0139] Furthermore, comparative LiFePO4 was produced. Of the above LiFePO4 manufacturing process, all processes performed under a nitrogen atmosphere are performed under an air atmosphere. This was done. The other production steps are the same as the LiFePO4 production method described above. Furthermore, the prepared comparative LiFePO4 samples were observed using a scanning electron microscope (SEM). The observation results are shown in Figure 9. vinegar.

[0140] Figure 8 shows that LiFePO4 has multiple rectangular crystals. Furthermore, Compared to Figure 9, the LiFePO4 shown in Figure 8 exhibits less variation in crystal shape. Therefore, it is more effective to produce LiFePO4 under a nitrogen atmosphere than through processing under an atmospheric atmosphere. The process described below allows for smaller variations in crystal shape when producing LiFePO4. This can be understood. [Explanation of Symbols]

[0141] 161 Rectangular prism 201 Positive electrode 202 Negative electrode 203 Electrolytes 204 Separator 211 Positive electrode current collector 212 Cathode active material layer 221 Negative electrode current collector 222 Negative electrode active material layer 301 Positive electrode 302 negative electrode 304 Separator 305 enclosure 306 cabinets 307 Ring-shaped insulator 308 Spacer 309 Washer 311 Positive electrode current collector 312 Cathode active material layer 321 Negative electrode current collector 322 Negative electrode active material layer 5000 display devices 5001 enclosure 5002 Display section 5003 Speaker section 5004 Energy Storage Device 5100 Lighting device 5101 enclosure 5102 Light source 5103 Energy storage device 5104 Ceiling 5105 Side wall 5106 floor 5107 Window 5200 indoor unit 5201 enclosure 5202 Air outlet 5203 Energy storage device 5204 Outdoor unit 5300 Electric Refrigerator / Freezer 5301 enclosure 5302 Refrigerator door 5303 Freezer door 5304 Energy storage device 6000a enclosure 6000b enclosure 6001a Panel 6001b Panel 6002 Shaft 6003 button 6004 Connection terminal 6005 Recording medium insertion section 6010 finger 6101 Power supply section 6102 Wireless Communication Section 6103 Arithmetic unit 6104 Audio section 6105 Panel section 6111 Energy storage device

Claims

1. General formula LiMPO ４ A method for producing a composite oxide represented by (where M is one or more of Fe, Co, Ni, and Mn), LiOH・H ２ O, FeCl ２ 4H ２ O, and NH ４ H ２ PO ４ Each of these is dissolved in water that has been subjected to nitrogen bubbling under a nitrogen atmosphere to produce a solution containing Li, a solution containing P, and a solution containing Fe, Under a nitrogen atmosphere, the Li-containing solution is added dropwise to the P-containing solution to produce a solution containing Li and P. Under a nitrogen atmosphere, the Fe-containing solution is added dropwise to the Li and P-containing solution to produce a mixed solution containing Li, P, and Fe. Add water that has been subjected to nitrogen bubbling to the aforementioned mixed solution. The mixed solution is reacted at a temperature of 150°C for 15 hours while being stirred under a nitrogen atmosphere. A method for producing a composite oxide, comprising filtering the mixed solution under an atmospheric environment, washing the remaining compound 10 times with pure water, and then drying the compound in a vacuum at a temperature of 50°C.

2. In the solution containing Li and P, Li ３ PO ４ precipitates. The method for producing a composite oxide according to claim 1.

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