WO2005095273A1

WO2005095273A1 - Method for producing lithium-iron composite oxide

Info

Publication number: WO2005095273A1
Application number: PCT/JP2005/006703
Authority: WO
Inventors: Ryoji Yamada
Original assignee: Seimi Chemical Co., Ltd.
Priority date: 2004-03-30
Filing date: 2005-03-30
Publication date: 2005-10-13
Also published as: JP2007230784A

Abstract

A novel method for producing a lithium-iron composite oxide, characterized in that it comprises finely pulverizing a raw material component containing an iron compound containing a trivalent iron, a lithium compound, a phosphoric acid derivative and a carbon-containing compound into pulverized particles having a 50 % volume cumulative diameter (D50) of 2 μm or less and a 90 % volume cumulative diameter (D90) of 10 μm or less, and then coagulating said pulverized particles into coagulated particles having a 50 % volume cumulative diameter (D50) of 30 μm or less and a 90 % volume cumulative diameter (D90) of 100 μm or less, and then heating the resultant particles at 300 to 1150°C, to thereby prepare LiFePO4 having an olivine type structure; and an electrode active material for a non-aqueous electrolyte secondary cell having a high discharge capacity and excellent charge-discharge characteristics which uses the lithium-iron composite oxide produced by the above method. The above method allows the production of an olivine type lithium-iron composite oxide exhibiting excellent electric cell characteristics, through the use of a non-expensive iron compound as a raw material.

Description

Description Manufacturing method of lithium iron composite material

The present invention relates to a method for producing a lithium iron composite oxide having an olivine type structure and an electrode active material for a non-aqueous electrolyte secondary battery containing the produced lithium iron composite oxide. Background art

High power and high energy density lithium ion secondary batteries have been recognized as energy sources for mopile equipment, and have rapidly been replaced by conventional Al-Lini batteries and nickel-metal hydride batteries. On the other hand, lithium-ion rechargeable batteries, which are medium-sized and large-sized batteries, are expected to be one solution that can alleviate the seriousness of environmental and energy problems, but safety concerns have not been resolved until now.

As a safe and inexpensive cathode active material, Mn-based and Fe-based studies have been conducted. In particular there was filed in the spinel L i Mn ₂ 0 ₄ «f force to study material can not overcome the disadvantages such poor stability during storage at a high temperature, not Itaritsu the secret practical application. Layered rock salt structure L i F e 0 ₂ has also been studied for many years, but the situation that is unable to express still satisfactory electrical chemical properties.

In contrast, since the L i F e P_〇 ₄ proposed by Patent Document 1, the oxygen of the positive electrode active substance involved in safety is firmly fixed covalently bound to all the phosphorus, very cheap In all, it was expected to be a cathode active material with excellent stability. However, its electrochemical properties have a problem that only 70% of the theoretical amount can be expressed (Non-Patent Document 1).

Challenges conventional L i F e P 0 ₄ faced is that L i F e P 0 ₄ no crystals were only lifting poor electronic conductivity. As a result, the insertion of lithium into the crystal and the elimination of lithium from the crystal did not easily proceed, the diffusion in the crystal was slow, and the charge and discharge could not be repeated smoothly. Also, Since L i F e P 0 ₄ is a compound of divalent iron, but had use divalent iron compounds so easy as an iron source, easy to handle bivalent iron compound is expensive poor limited versatility.

One method for overcoming the above problems is to atomize the active material (Non-Patent Document 2). As a result, the surface that can contribute to the charge transfer reaction can be increased, and the electron transfer distance in the crystal can be reduced. Non-Patent Document 2, it has been reported that achieved L i F e P 0 ₄ The prepared discharge capacity 1 6 O mAh / g containing particle size 1 0 zm following particle. However, this is an iron compound having a valence of 2 and using extremely expensive iron acetate as an iron source, and it is difficult to develop load characteristics in which sintered particles are generated frequently.

It has been reported that the electrochemical properties can also be improved by applying a conductive coating to the surface of the active material particles to increase the conductivity between the particle surface and the electrode composite. It is also effective to use a carbonaceous material used as a conductive additive for composites for conductive coating of particles. Non-Patent Document 3, by using L i F e P 0 ₄ obtained by firing a mixture of phenolic resins derived from carbon and the raw material has been reported to be able to exhibit a high discharge capacity even at a high load. However, also in this case, expensive iron acetate is used as the iron source.

Patent Document 2, a method for compounding a carbon material particles to L i F e P_〇 ₄ particles having an average particle diameter of 0. 2 to 5 m has been proposed. However, the initial discharge capacity of the battery assembled using the active material thus prepared can exhibit only a low characteristic of 88 mA hZg, despite the fact that iron oxalate, a ferrous compound, is used as the iron source. . This is considered to be because the battery performance of difficult-to-handle fine particles could not be brought out well.

Attempts are being made to improve the electrochemical properties of the active material by increasing the conductivity of the crystal itself. Non-Patent Document 4, N b Z r such L i F e P 0 ₄ of the electronic conductivity 8 digits enhanced by 1 mol% doping, it is broadcast capable of expressing excellent battery performance in the high load characteristics It has been tell. However, these were also studied using the iron (II) oxalate, a ferrous compound, as an iron source, and are not economically practical.

Versatile, it has also been studied attempts to synthesize L i F e P_〇 ₄ using inexpensive iron compound. Non-Patent Document 5, with a F e ₂ 〇 ₃ which is a compound of inexpensive trivalent iron readily available iron source, a reducing agent for the divalent iron carbonaceous material from trivalent iron Synthesized i Fe _0. ₉ Mg. iPO is reported to exhibit good battery performance. However, XRD profiles of L i FeP_〇 ₄ in the report intended to residual diffraction peaks of unreacted iron oxide, indicating that the reaction was not complete.

Synthesis of L i F e P0 ₄ that also express good battery performance conventional as described above but was filed possible, they be those divalent iron compounds by synthesis method as a raw material, cheap L i F e P0 ₄ from a point to be cane abundantly and stably supplied is not practical.

On the other hand, good freely handled at low cost, as the readily available iron compounds for iron oxide is advantageous, technique for synthesizing L i F e P_〇 ₄ iron oxide as an iron source was also known in the art . However, the reaction could not be completed and the high-load characteristics were greatly reduced, so that it was not practically used.

[Patent Document 1] Japanese Patent No. 3319258

[Patent Document 2] Japanese Patent Application Laid-Open No. 2003-36889

[Non-Patent Document 1] J. Electrochem Soc. 144, 1188 (1997)

[Non-Patent Document 2] J. Electrochem Soc. 148.A224 (2001)

[Non-Patent Document 3] ElectrocheE Sol id-State Lett. 4, A170 (2001)

[Non-Patent Document 4] Nature Mater.% 123 (2002)

[Non-Patent Document 5] ElectrocheE Sol id-State Lett. 6, A53 (2003) Disclosure of the Invention

The present invention overcomes the above-mentioned problems of the prior art, and uses a general-purpose and inexpensive iron compound containing trivalent iron as a raw material, and can perform a synthesis reaction while maintaining an optimal particle shape for expressing battery characteristics. It is an object of the present invention to provide a novel method for producing a lithium iron composite oxide, and an olivine-type lithium iron composite oxide produced by such a method and having high discharge capacity and excellent charge / discharge characteristics.

The inventor of the present invention has conducted intensive research to achieve the above object, and has refined a raw material component containing an iron compound having a valence of 3, an iron compound, a lithium compound, a phosphoric acid compound, and a carbon-containing compound. After reducing the 50% volume cumulative diameter (D50) of the finely divided particles to 2m or less and the 90% volume cumulative diameter (D90) to 10m or less, the ^ :! Agglomeration treatment of the particles The 50% volume cumulative diameter (D 50) of the aggregated particles is 30 m or less, and 90% # ^ cumulative diameter

After (D 90) is reduced to 100 m or less, heat treatment is performed at 300 to 1150. Preferably, the 50% volume cumulative diameter (D 50) is 30 m or less, and 90% or less. An olivine-type structure Li Fe PO having a% volume cumulative diameter (D 90) of 100 m or less has been achieved. The invention's effect

According to the production method of the present invention, the fine iron compound and the fine carbon-containing compound are homogeneously distributed in the raw material components, and the carbon is almost quantitatively converted from the adjacent trivalent iron to the divalent iron. reduced to, and acts to retain the divalent, with performing the synthesis reaction of L i F e P 0 _4, functions to prevent undesirable side reactions reoxidation like. Aggregated particles of raw material components with pre-controlled particle size distribution also acts to also maintain many of the features of the distribution before the heat treatment after a L i F e P 0 ₄ is heat treated, It functions to prevent excessive sintering of primary and secondary particles.

Thus, the lithium-iron composite oxide of the present invention is composed of agglomerated particles having a controlled particle diameter, in which fine primary particles are collected, and a carbonaceous particle layer derived from a carbon-containing compound is provided on the surface of the primary particles. Have been. The non-aqueous electrolyte secondary battery using the lithium-iron composite oxide of the present invention as a positive electrode active material, which reflects such a form, smoothly promotes an interfacial electrokinetic reaction and exhibits excellent battery characteristics. In other words, a large current can flow and power can be obtained, and highly reliable safety and long life can be achieved.

On the other hand, in the conventional lithium-iron composite oxide, the unreacted portion and the reoxidized portion were left because of insufficient mixing of raw materials having greatly different specific gravities. In addition, independent primary particles and fine secondary particles became a binder during heat treatment, and large primary particles and aggregated particles were frequently generated. It is presumed that such a problem caused the cycle characteristics and load characteristics to deteriorate when the conventional lithium iron composite oxide was used as an electrode active material for a non-aqueous electrolyte secondary battery I] Is done. Brief Description of Drawings 1, X-rays diffraction pattern diagram of the L i F e P 0 ₄ prepared in Example 1 (A).

_{2, L i F e P 0 4} (A) and the particle size distribution diagram of its ingredients slurry ingredients powder prepared in Example 1.

Figure 3 is a scanning electron microscope (S EM) observation photograph of L i F e P 0 ₄ prepared in Example 1 (A). BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is the synthesis of a divalent iron compound L i F e P_〇 _4, can also be achieved in the raw material or we containing trivalent iron, it is characterized in that compatible with expression of the high-performance battery characteristics . Accordingly, the iron raw material that can be used in the present invention is not limited at all, and can be used by selecting from a wide range of iron compounds. However, it is preferable to use iron oxide as an iron raw material component in the present invention because it is easy to obtain and handle and is inexpensive. Is an iron oxide not only F e ₂ 〇 _{_3,} F e ₃ 0 ₄ or F e OOH like are also suitably used. Needle-like iron oxide having strong anisotropy is also preferably used.

As the lithium compound used in the present invention, any compound containing lithium can be used. However, lithium oxides, hydroxides, salts, or a mixture of two or more of these compounds are preferable from the viewpoint of easy handling.

The phosphate compound used in the present invention is not limited at all. However, since they are easily available and easy to handle, phosphate esters such as phosphoric acid, iron phosphate, lithium phosphate and ammonium phosphate, and 2-ethylhexyldiphenyl phosphate triethyl diphosphate can be exemplified. It can be used preferably.

The carbon-containing compound that can be used in the present invention can be selected from a wide range of compounds containing carbon. However, preferably, a compound having a carbon content of at least 35% by weight and exhibiting a liquid state or a solid state at normal temperature is preferable because the reduction reaction from trivalent iron to divalent iron can efficiently proceed. Specifically, reducing sugars such as glucose, sucrose, and lactose; organic compounds such as ethylene oxide, glycerin, ascorbic acid, lauric acid, and stearic acid; water-soluble high-molecular compounds such as polyvinyl alcohol and polyethylene dalicol; polypropylene , Such as polystyrene, polyacrylonitrile, cellulose, epoxy resin, and phenol resin. Examples include carbonaceous materials such as racks, power pump racks, and graphite. As the carbon-containing compound, the material can be used as it is, but it can also be used in the form of a solution, emulsion, suspension or the like.

The raw material component including the iron compound having a valence of 3, iron compound, lithium compound, phosphoric acid compound, and carbon-containing compound is subjected to micronization treatment. The micronization process is performed through the process of pulverizing and crushing the raw material components. Each raw material component can be used alone, or two or more raw material components can be simultaneously subjected to micronization treatment. The raw material components subjected to the micronization treatment are preferably mixed uniformly. In the present invention, the thinning treatment and the mixing step can be performed independently of each other, but two treatments can be performed almost simultaneously.

It is preferable to perform the above-mentioned fine processing of the raw material components by using a slurry formed from the raw material components and the dispersion medium, since sufficient fineness can be achieved while preventing dissipation. The dispersion medium of the slurry may be a solvent for the raw material components. As the dispersing medium, any of a 7-based system, a hide-type carbon system, and a halogenated carbon system can be used. Among them, an aqueous dispersion medium is particularly preferable because it is easy to handle and inexpensive.

In the present invention, any method such as applying a shearing force to the slurry can be used as a method for subjecting the raw material component to the above-described slurry treatment in the form of fine particles. Above all, the slurry consisting of the raw material and the dispersion medium can be efficiently separated into fine particles and the mixture of the dispersion medium can be controlled at a low speed. Station-A method of miniaturization through the evening, a method of jetting with high pressure from a nozzle and colliding with each other, or a method of miniaturization by colliding with a shield, or causing cavitation during slurry It is preferable to use a method such as miniaturization, a bead mill, a planetary pole mill, or a pole mill.

In this way, in the refining treatment, the D50 of the finely divided particles of the raw material component should be 2 m or less, preferably 1 m or less, and D90 should be 10 or less, preferably 5 m or less. I like it. If D90 is larger than 10 m, the synthesis reaction cannot be completed, and the battery characteristics will be greatly impaired. On the other hand, if D50 is larger than 2, the cycle characteristics and load characteristics are impaired, which is not preferable. The above-described slurry refinement of the raw material components can be performed for each raw material component alone, or two or more raw material components can be simultaneously processed. In the latter case, the homogenous mixing of each raw material can be completed simultaneously with the refinement treatment of each raw material component.

In the present invention, the raw material components and particles that have been subjected to the miniaturization treatment are then aggregated. The method of aggregating the raw material component particles can be carried out by various means, and the agglomerated particles are preferably obtained in a dry state. Thus, for example, a method is preferred in which the slurry obtained by the micronization treatment is preferably subjected to agglomeration of the raw material components, removal of the solvent, and drying under heating and / or reduced pressure while applying a shearing force while preferably stirring. As a result, almost all of the raw material components can be recovered, and the particle size of the obtained aggregated particles can be easily controlled.

Further, a means for simultaneously aggregating and drying the raw material component particles by supplying the micronized slurry into the dry air stream is also preferably used. Furthermore, by coagulating and drying the raw material components by spray-drying the micronized slurry, it is suitable for the present invention.

The raw material component thus subjected to agglomeration treatment; ^, the D50 of the agglomerated particles of the raw material component is 30 Aim or less, preferably 20 m or less, and D90 is 100 m or less, preferably It is preferred to be 60 m or less. If D50 is larger than 30, cycle characteristics and load characteristics will be impaired. On the other hand, if D90 is larger than 100 / m, the synthesis reaction cannot be completed, and the battery characteristics are greatly impaired, which is not preferable.

In the present invention, then, the raw material components are agglomerated and the particles are heat-treated at 300 to 115 ° C., preferably 350 to 110 ° C. 0 ₄ is synthesized. Particle size of the olivine emission structure of L i F e P_〇 ₄ also, for the same reason, 50% volume cumulative diameter (D 5 0) is 3 0 m or less, or less preferably 2 0 m, and 9 The 0% volume cumulative diameter (D90) is preferably 100 m or less, more preferably 60 m or less. If the heat treatment temperature is lower than 300 ° C., the synthesis reaction is difficult to complete, and if it is higher than 115 ° C., an undesired reactant is generated, making it difficult to repair.

The preferred treatment time for the heat treatment varies greatly depending on the degree of miniaturization of each raw material component, the uniformity of mixing, the heating system, the treatment temperature, and the like. In the present invention, it is preferable that the heat treatment is performed within a range of several seconds to 48 hours. L i F e synthesis of P_〇 _4, the order of seconds one Can also be completed. Although it is possible to further reduce the processing time, no improvement in the characteristics is observed, and even if the heat treatment is continued for more than 48 hours, it is difficult to improve the characteristics.

The above heat treatment of the present invention are those which proceed essentially trivalent L i F synthesis of e P 0 ₄ of reduced to olivine structure iron compound bivalent, the oxygen concentration in the treatment atmosphere control also affect the synthesis reaction of L i F e P 0 _4. In the present invention, since the carbon-containing compound in the raw material component functions as a reducing agent in the vicinity of the raw iron compound, the heat treatment can be completed as it is in the air atmosphere. In particular, when a method that can complete the reaction with a short heat treatment is used, or when the ratio of the atmosphere gas in the heat treatment atmosphere is small relative to the raw material, there is no problem even if the atmosphere is left as it is.

The heat treatment can be performed in an inert atmosphere or in an inert gas stream. By making the heat treatment atmosphere inactive, it is preferable because restrictions on equipment and processing conditions are reduced and various heat treatment methods can be adopted. Further, in the present invention, the heat treatment can be performed in a reducing gas atmosphere such as hydrogen or carbon monoxide. In order to prevent excessive reduction of raw materials, it is effective to dilute the reducing gas with an inert gas such as nitrogen. In the present invention, a method of spray pyrolysis directly L i F e P 0 ₄ may be the synthesized from the slurry of starting components used. By supplying the slurry subjected to the micronization treatment while spraying it into the furnace adjusted to the heat treatment temperature of the present invention, the coagulation, drying, and heat treatment of the raw material components proceed almost simultaneously, and L i Fe P 0 ₄ arbitrariness preferred because it can be synthesized in one step a. Atmosphere control during spray pyrolysis can be adjusted by using compressed air, inert gas or reducing gas for spraying. Furthermore, it is also possible to use a method of using a combustion furnace to spray the slurry into a reducing flame to advance the reduction reaction.

The olivine-type structure lithium-iron composite oxide produced by the present invention may contain other substances for the purpose of improving powder properties and electrochemical properties. For example, zinc, aluminum, sulfur, indium, cadmium, gallium, calcium, chromium, copalile, zirconia, tin, strontium, cerium, tungsten, tantalum, titanium, copper, thorium, lead, niobium, nickel, vanadium , Norium, bismuth, fluorine, beryllium, boron, magnesium, manganese, molybdenum and the like are preferably used. They are It is used alone or in the form of various compounds, alone or in combination of two or more kinds, and is blended into the inside and / or the surface of the lithium iron composite oxide of the present invention.

These auxiliary substances may be used alone or in the form of powders, liquids, solutions, and dispersions of oxidants, hydroxides, peroxides, salts, alkoxides, acylates, chelates, and the like. Used in form. These substances may be added to the raw material components in the above-described production process of the lithium iron composite oxide, or may be added to the lithium iron composite oxide after the lithium iron composite oxide is synthesized. You can also.

The olivine-type structure lithium-iron composite oxide produced by the method of the present invention is effectively used as a positive electrode active material for battery electrodes and secondary battery electrodes. In particular, it is extremely effective as a positive electrode active material for non-aqueous electrolyte secondary batteries such as lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries, including lithium primary batteries. The non-aqueous electrolyte secondary battery using the electrode active material of the present invention has a large charge / discharge capacity and a high energy density, and exhibits excellent cycle characteristics, high load characteristics, low temperature characteristics, high temperature characteristics, and safety. . In particular, the lithium-iron composite oxide of the present invention, which achieves both high energy density and high load characteristics, as well as highly reliable safety, is a positive electrode active material for medium and large-sized secondary batteries and secondary batteries for vehicles. Can be applied effectively. Example

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto. In the examples, the capacity retention rate was determined by the following equation.

Retention rate (%) = 100th cycle discharge capacity * Initial discharge capacity

X 1 0 0

Example 1

An agglomerate of needle-like crystals having an average particle length in the major axis direction of 1. Cm was obtained, and iron oxide having an iron content of 69.4% by weight was obtained. 79.8 g of this iron oxide, 1 of ammonium dihydrogen phosphate

5.0 g, 36.9 g of lithium carbonate, and 6.lg of carbon black (carbon content 95.7% by weight) were weighed into a stainless steel vat, and pure water was added to make 3 kg. . This was passed through a homogenizer consisting of a high-speed rotating mouth and a stirrer while stirring.

A raw material component slurry was obtained in which 0 was 0.64 m and D90 was 0.99 m. This slurry As a result of being supplied with a large amount of hot air during the high-speed rotation of the cutlet and dried, a raw material component powder of 050 4.37 and D90 of 10.1 m was obtained.

This raw material component powder was heat-treated in a nitrogen gas flow of 0.8 liter / min at 600 ° C for 24 hours, and D 50 was 5.10 urn and D90 was 11. l ^ m Li FeP〇 ₄ ( A) 138. lg was obtained. Figures 1, 2, and 3 show the Χϋ diffraction pattern, particle size distribution, and SEM observation photographs, respectively. From FIG., (Alpha) has an olivine structure, fine primary particles are aggregated, it is understood that crystalline good is L i F e P0 _4.

20 parts by weight of N-methylpyrrolidone were added to 90 parts by weight of this (A), 5 parts by weight of carbon dioxide, and 5 parts by weight of polyvinylidene fluoride, and kneaded to obtain a paste. This paste was applied to an aluminum foil, dried, rolled and punched into a predetermined size to obtain a positive electrode plate. Next, 95 parts by weight of nylon and 5 parts by weight of polyvinylidene fluoride were mixed with 20 parts by weight of N-methylpyrrolidone to obtain a paste. This paste was applied to a copper foil, dried, rolled and punched into a predetermined size to obtain a negative electrode plate.

Lead wires were attached to the thus obtained positive electrode plate and negative electrode plate, respectively, and housed in a stainless steel cell case via a polyolefin-based separator. Subsequently, an electrolyte solution in which lithium hexafluorophosphate was dissolved at a concentration of 1 mol / L was injected into a mixed solution of ethylene carbonate and diethylene nitrate, to obtain a model cell. Battery characteristics a charge-discharge measuring instrument was used, 2 5 ° battery voltage with a charging current 0. 6 A / cm ² at C 4. 3 discharge current was charged to a ^{V 2. 0mA / cm 2 1 (} 1. (Equivalent to 25 C rate) Discharging until the voltage reaches 2.0 V The charge and discharge were repeated, and the initial discharge capacity and the discharge capacity after 100 cycles were obtained and evaluated. The results are shown in Table 1.

Example 2

Ribonbon Black 6. Homogenizer treatment as in Example 1 except that instead of lg, 50 g of a polystyrene resin with a resin content of 1.7.3% by weight (carbon content of 92.3% by weight) was used. As a result, a raw material component slurry having a D50 of 0.68 tm and a D90 of 0.98 m was obtained. The slurry was dried under reduced pressure at 92 with high-speed stirring to obtain a raw material component powder having a D50 of 5.41 urn and a D90 of 15.5 m. This raw material component powder is heat-treated at 500 ° C for 24 hours in a 0.8 L / min nitrogen gas stream, D50 is 5. 56 m, D90 was obtained _{L i F e P0 4 (B} ) 152. 8g of 19. 2 m.

Except that this (B) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the results of examining the charge / discharge characteristics are shown in Table 1.

Example 3

An iron oxide having an iron content of 69.5% by weight and an average aggregated particle diameter of 2.1 in which sub-micron-order pseudo-spherical particles were collected was obtained. 79.8 g of this iron oxide, 115.0 g of ammonium dihydrogen phosphate and 36.9 g of lithium carbonate were weighed in a stainless steel vat, and pure water was added to make 3 kg. This was bead milled for 1 hour using a 0.5 mm zirconia pole, and 90 g of a 13.3% by weight aqueous solution of polyvinyl alcohol (carbon content: 54.5% by weight) was added, followed by stirring and mixing. Thus, a raw material component slurry having a D50 of 0.72 nm and a D90 of 1.29 m was obtained. The slurry was fed into a large amount of hot air flowing at high speed and dried to obtain a raw material component powder having a D50 of 5.17 zm and a D90 of 12.2 xm. The ingredients powder was heat-treated for 5 hours at the 0.8 liters Z content of nitrogen gas flow 700 ° C, D50 is 6. 21 urn, D90 of 20. 8 m L i F e P0 4 (C) 134.6 g were obtained.

Except that this (C) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 4

79.8 g of the iron oxide of Example 1, 115.0 g of ammonium dihydrogen phosphate, 36.9 g of lithium carbonate, and 6.1 g of a power pump rack were weighed into a stainless steel vat, and pure water was added to make 3 kg. When this was subjected to a bead mill treatment in the same manner as in Example 3, a raw material component slurry having a 050 of 0.49 m and a D90 of 0.83 m was obtained. When this slurry was spray-dried, a raw material component powder having a D50 of 4.59 m and a D90 force of 9.86 m was obtained. The raw material Ingredient powder was heat-treated at 0.8 liters / min nitrogen gas stream 650 for 12 hours, D 50 is 5. 27 urn, D90 of 10.4 / 111 1 ^ 1 6? 〇 ₄ ( D) 129.8 g were obtained.

Except that this (D) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results. Example 5

D50 was 0.64 m and D90 was 1.00 in the same manner as in Example 4, except that the slurry was discharged from the two nozzles facing each other at high pressure and collided with each other instead of bead milling. Thus, m raw material component slurries were obtained. The slurry was heat-treated while spraying with nitrogen gas into the furnace set at 875 ° C, D 50 is 10. 6 m, D 90 is 23. 2 ^ m of _{L i FeP0 4 (E) 115} . 2 g were obtained.

Except that this (E) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 6

When the same raw material component slurry as in Example 5 was spray-dried, a raw material component powder having a D50 of 8.03 m and a D90 of 13.5 m was obtained. This raw material component powder is spread on an alumina tray, covered with an alumina plate, and heat-treated in a microwave oven at 600 ° C for 2 minutes in an air atmosphere. D50 is 8.15 τ and D90 is 12.7 1? 6? ₄ (F) 13 0.2 g of 111 were obtained.

Except that this (F) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the results of examining the charge / discharge characteristics are shown in Table 1.

Example 7

D50 was 0.68 m and D90 was 1.05 X in the same manner as in Example 4, except that the slurry was passed through the gap between the disk rotating at high speed and the fixed disk instead of bead milling. m raw material component slurry was obtained. The slurry was dried in the same manner as in Example 1, and as a result, a raw material component powder having a D50 of 5.44 m and a D90 of 10.8 xm was obtained. This raw material powder was heat-treated using a low-temperature kiln while flowing nitrogen gas for 1.5 liters Z, and the D50 was 5.58 rn, 090 10.8 to 1? 0 ₄ (G) 140.5 was obtained. The heat treatment applied to the raw material component powder at this time was 1 minute at 1085 ° C.

Except that this (G) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 8 Fe3 e4 formed by agglomeration of pseudo-spherical primary particles having an average particle diameter of 0.6 and iron oxide of Example 3 were mixed to prepare an iron oxide mixture having an iron content of 70.4% by weight.

In the same manner as in Example 4, except that sucrose (carbon content: 42.1% by weight) was used instead of the oxidation in Example 1, D 50 was 0.57 im, and D 90 was 1.1 xm. A raw material component slurry having a D50 of 4.96 m and a D90 of 11.3 m was obtained. The ingredients powder for 30 hours heat set at a 0.8 l Z content of nitrogen gas flow 450 ° C, D50 is 5. 04 ^ m, D90 of 11. 0 m L i FeP_〇 ₄ (H ) 130.3 g were obtained.

Except that this (H) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 9

An agglomerate of needle-like crystals having a long-axis average particle length of 0.8 was obtained. This FeOOH and the iron oxide of Example 1 were mixed to prepare an iron oxide mixture having an Fe content of 63.9% by weight.

In the same manner as in Example 4, except that 87.4 g of the iron oxide mixture was used instead of 79.8 g of the iron oxide of Example 1, the raw material components in which 050 was 0.45 mm and 090 was 0.75 m A slurry was obtained, and a raw material powder having a D50 of 4.63 m and a D90 of 9.57 / xm was obtained. The ingredients powder was 24 hours heat treatment at 0.8 liters Z content of nitrogen gas flow 550 of this, D50 is 4. 85 rn, D90 is 9. 88 m of _{L i FeP0 4 (J) 127.} 4g Was obtained.

Except that this (J) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 10

79.8 g of ultrafine iron oxide with an average particle size of 0.03 m, 11.50 g of ammonium dihydrogen phosphate, 36.9 g of lithium carbonate, 6.19 g of power pump rack Heat treatment was conducted in the same manner to obtain 154.0 g of LiFeP ( ₄ (K) having 050 of 29.8 rn and 090 of 97.4ΠΙ. Except that this (K) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 11

200 g of the iron oxide of Example 1 was weighed into a stainless steel vat, and purified water was added to make 3 kg. This was subjected to a bead mill treatment in the same manner as in Example 4 to obtain an iron oxide slurry in which 050 was 0.40 mm and 090 was 0.66 / m. When this slurry was spray-dried, iron oxide powder having a D50 of 5.3 m and a D90 of 10.7 m was obtained.

79.8 g of this iron oxide powder, 115.0 g of ammonium dihydrogen phosphate, 36.9 g of lithium carbonate, and 6.1 g of power pump rack were mixed in a mortar to obtain a raw material component powder. This was heat-treated in the same way as Example 4, D 50 is 30. 7 m, D90 was obtained _{L i Fe P0 4 (L)} 152. 8g of 107. 5 m.

A model cell was prepared in the same manner as in Example 1 except that this (L) was used instead of (A), and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 12

The 50 g of (L) was ball milled in ethanol media, D 50 is 6. 72, D 9 0 got 1 6? 〇 ₄ (M) 48. 3 g of 31.1 / 111.

Except that this (M) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 13

A raw material component slurry was obtained in the same manner as in Example 4. The slurry was dried under reduced pressure at an evaporator, and pulverized with a cutlet mill to obtain a raw material powder having a D50 of 12.5 m and a D90 of 140.9 m. This was heat-treated in the same manner as Example 4, D 50 was obtained L i FeP_〇 _{4 (Ν)} 121. 5g of 25. 9 πι, D 90 ^ 1 50. 6 ^ m.

Except that this (N) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 14 D 50 was 4.47 μ, πι, and D90 were 9.81 zm, as in Example 4, except that the heat treatment, which was 12 hours at 650, was replaced with 48 hours at 250 ° C. Ρ 0 ₄ (Ρ) 1 30.5 g was obtained.

Except that this (P) was used instead of (A), a model cell was created in the same manner as in Example 1 and charge / discharge characteristics were examined, but charging / discharging was not possible.

Example 15

LiFeP0 with a D50 of 59.2 m and a D90 of 257 m in the same manner as in Example 4, except that the heat treatment was changed from 12 hours at 650 ° C to 12 hours at 1250 ° C. ₄ (Q) 1 23.6 g was obtained.

Except that this (Q) was used in place of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results.

Example 16

79.8 g of the iron oxide of Example 1, 115.0 g of ammonium dihydrogen phosphate, 36.9 g of lithium carbonate, 6.1 g of power pump rack and 200 g of isopropyl alcohol were weighed into a stainless steel spat, and pure water was added. In addition, the weight was 3 kg. This was subjected to bead milling for 1 hour to obtain a raw material component slurry having a D50 of 0.59 m and a D90 of 0.98 im. When this slurry was spray-dried, a raw material component powder having a D50 of 1.92 rn and a D90 of 4.49 m was obtained. This raw material powder was heat-treated at 550 ° C for 5 hours while supplying 0.8 liters of nitrogen gas containing 10 V o 1% of hydrogen, and D 50 was 2.67 m and D 90 was 4. 53 was obtained _{L i Fe P0 4 (R)} 130. 2g of zm.

Except that this (R) was used instead of (A), a model cell was prepared in the same manner as in Example 1, and the charging and discharging characteristics were examined. Table 1 shows the results. table 1

The contents of the entire specification of Japanese Patent Application No. 2004-100021 (filed with the Japan Patent Office on March 30, 2004), which is the basis of the priority claim of the present application, are cited here, and It is incorporated as disclosure of the detailed text.

Claims

The scope of the claims

1. A raw material component containing an iron compound having a valence of 3 and containing an iron compound, a lithium compound, a phosphate compound, and a carbon-containing compound is refined, and a 50% volume cumulative diameter (D50 ) Is set to 2 / im or less, and the 90% volume cumulative diameter (D 90) is reduced to 10 m or less. Then, the micronized particles are subjected to aggregating treatment, and the 50% volume cumulative diameter (D50) of the agglomerated particles is determined. 30 or less and 90% volume cumulative diameter (D90) was heat treated at 300 to 1,150 ° C in brought below 100 m, and wherein the obtaining a L i FeP0 ₄ of olivine structure, lithium Tetsufuku if oxide Method of manufacturing a product.

2. The olivine-type L i FeP 0 ₄ structures, 50% volume cumulative diameter (D 50) as a 3 0 / xm or less, and a 90% volume cumulative diameter (D 90) in claim 1 having a 100 m or The manufacturing method as described.

3. The production method according to claim 1, wherein the carbon-containing compound has a carbon content of 35% by weight or more and exhibits a liquid state or a solid state at ordinary temperature.

4. The production method according to any one of claims 1 to 3, wherein the raw material component is finely treated on a slurry formed from the raw material component and a dispersion medium.

5. The production method according to any one of claims 1 to 4, wherein the aggregation of the fine particles is performed by separating and recovering raw material components from the slurry after the fine processing.

6. The production method according to claim 1, wherein the heat treatment is performed in the air, in an inert atmosphere, or in a reducing atmosphere.

7. The production method according to any one of claims 1 to 6, wherein the aggregation treatment and heat treatment of the fine particles are performed by a spray pyrolysis method of spraying the slurry after the fine treatment into a heating furnace.

8. An electrode active material for a non-aqueous electrolyte secondary battery, comprising the lithium iron composite oxide obtained by the production method according to claim 1.