JP2002367612A - Lithium ferrite with cadmium chloride structure, manufacturing method of the same, and cell using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium ferrite with cadmium chloride structure having excellent characteristics which can be simply manufactured at low cost, and to provide a manufacturing method of the same, and a cell using the same. SOLUTION: A positive electrode 12 and a negative electrode 14 is arranged with a separator 15 interposed between them. The positive electrode 12 contains a lithium ferrite with cadmium chloride structure. For the ferrite with cadmium chloride structure (LiFeO2 with CdCl2 structure), the integrated intensity ratio of the diffraction peak of (003) against the diffraction peak of (104), obtained by the powder method of X ray diffraction, is 2.5 or more, or the half value width of the diffraction peak of (003) is 0.45 of less. Namely, the ferrite has high orientation property or high crystalline property. The lithium ferrite with cadmium chloride structure is obtained by making α-sodium ferrite (NaFeO2 ), obtained by the solid phase reaction of sodium hydroxide and iron source material, exchange ion in an inorganic lithium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cadmium chloride type lithium ferrite, a method for producing the same, and a battery using the same.

[0002]

2. Description of the Related Art At present, lithium ion secondary batteries are widely used as driving power supplies for portable electronic devices or electric devices. As a positive electrode material of a lithium ion secondary battery, for example, a lithium-cobalt composite oxide (LiCoO ₂ ), a lithium-nickel composite oxide (LiNiO ₂ ) having a layer structure (cadmium chloride type), or a solid solution thereof are practically used. Have been. However, while these materials can achieve high operating voltages and high capacities, they are expensive due to the relatively scarce presence of cobalt (Co) and nickel (Ni) in the earth's crust, and the cost of the cathode material is reduced overall. This accounts for one-third, which is a factor that hinders the market expansion of lithium ion secondary batteries.

As a next-generation, low-cost, high-voltage positive electrode material, lithium manganese spinel such as LiMn ₂ O ₄ or lithium ferrite (LiFeO ₂ ) has been attracting attention and research and development have been carried out. In particular, since lithium ferrite uses abundant iron (Fe) as a resource, it is most expected as a next-generation low-cost cathode material.

However, when lithium ferrite is produced by a conventional solid-phase reaction using a lithium compound and an iron compound, a rock salt type α-lithium ferrite in which cations are randomly distributed, or an ordered rock salt type γ. -Only lithium ferrite can be obtained (JCAnders
on and M. Schieber, J.phys.Chem.Splids, 25, (1964)
961-968). Therefore, there is an urgent need to establish a method for producing cadmium chloride (CdCl ₂ ) type lithium ferrite having the same crystal structure as a lithium-cobalt composite oxide or a lithium-nickel composite oxide.

At present, the following three types of methods for synthesizing this cadmium chloride type lithium ferrite are known. The first is a method in which α-sodium ferrite is ion-exchanged in a molten salt containing lithium ions.
Is a method of subjecting .alpha.-sodium ferrite to solvothermal treatment together with an inorganic lithium salt in a non-aqueous solvent.

[0006]

However, the above-mentioned method using the second solvothermal treatment or the third method using the direct hydrothermal treatment requires special equipment such as a hydrothermal reactor such as an autoclave. age,
There is a problem that equipment cost increases when mass production is performed. Moreover, compared to the desired amount of reaction product,
Because it requires a very large amount of raw alkali metal salt,
There was also a problem of inefficiency.

In the first method using ion exchange, the sodium compound as a raw material is sodium peroxide (Na).
₂ O ₂ ), sodium hydroxide (NaOH) or sodium carbonate (Na ₂ CO ₃ ) are used.
Sodium peroxide must be handled in a glove box or the like, and there is a problem that its use is difficult, explosive and dangerous. In addition, sodium hydroxide is commercially available in the form of granules, and it is troublesome to use a small amount of water when mixing with an iron compound, or to mix with an iron compound after preparing an aqueous sodium hydroxide solution. There was a problem. Further, sodium carbonate has a problem that an impurity layer different from the target substance is often observed. Therefore, development of a new practical process in place of these has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is a cadmium chloride type lithium ferrite which can be easily manufactured at low cost and has excellent characteristics, a method of manufacturing the same, and a battery using the same. Is to provide.

[0009]

The cadmium chloride type lithium ferrite according to the present invention has an integral intensity ratio of the diffraction peak of (003) to the diffraction peak of (104) obtained by the powder X-ray diffraction method of 2.5 or more. belongs to.

Another cadmium chloride type lithium ferrite according to the present invention is obtained by powder X-ray diffraction (0000).
The half width of the diffraction peak of 3) is 0.45 or less.

The method for producing cadmium chloride-type lithium ferrite according to the present invention comprises the step of producing α-sodium ferrite by causing a solid phase reaction between sodium hydroxide and at least one of the group consisting of an iron compound and metallic iron. And a step of ion-exchanging the obtained α-sodium ferrite in an inorganic lithium salt to produce a cadmium chloride-type lithium ferrite.

The battery according to the present invention has a positive electrode containing cadmium chloride-type lithium ferrite. The cadmium chloride-type lithium ferrite has a (00) diffraction peak corresponding to (104) obtained by a powder X-ray diffraction method.
The integrated intensity ratio of the diffraction peak of 3) is 2.5 or more.

Another battery according to the present invention is provided with a positive electrode containing cadmium chloride-type lithium ferrite, and the cadmium chloride-type lithium ferrite has a half of a diffraction peak of (003) obtained by a powder X-ray diffraction method. The value range is 0.45 or less.

The cadmium chloride type lithium ferrite according to the present invention is obtained by powder X-ray diffraction (10
Since the integrated intensity ratio of the diffraction peak of (003) to the diffraction peak of 4) is 2.5 or more, it has high orientation.

Another cadmium chloride type lithium ferrite according to the present invention is obtained by powder X-ray diffraction method (0
Since the half width of the diffraction peak of 03) is 0.45 or less, it has high crystallinity.

In the method for producing cadmium chloride-type lithium ferrite according to the present invention, α-sodium ferrite is obtained by a solid-phase reaction of sodium hydroxide with at least one of the group consisting of iron compounds and metallic iron.

In the battery according to the present invention, the cadmium chloride-type lithium ferrite of the present invention is used for the positive electrode.
High charging capacity is obtained.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The cadmium chloride type lithium ferrite according to one embodiment of the present invention is typically represented by, for example, a chemical formula shown in Chemical formula 1. Although Chemical Formula 1 is represented by a stoichiometric composition, the cadmium chloride-type lithium ferrite is not limited to the stoichiometric composition, and may not be a stoichiometric composition.

[0020]

Embedded image CdCl ₂ type LiFeO ₂

This cadmium chloride type lithium ferrite has a high orientation, and the integrated intensity ratio ((003)) of the diffraction peak of (003) to the diffraction peak of (104) obtained by the powder X-ray diffraction method. Diffraction peak / (1
04) is 2.5 or more. The integrated intensity ratio is more preferably 3 or more, and even more preferably 6 or more. The cadmium chloride type lithium ferrite has high crystallinity, and the half width of the diffraction peak of (003) obtained by the powder X-ray diffraction method is larger than zero and equal to or less than 0.45.

The cadmium chloride type lithium ferrite having such a structure can be manufactured as follows.

First, a granular sodium hydroxide as a sodium source material and at least one of a group consisting of an iron compound and a metallic iron as an iron source material are prepared. Examples of the iron compound include a water-soluble iron salt, iron hydroxide and iron oxyhydroxide. Sodium hydroxide is used in the form of granules. In addition, since sodium hydroxide has water absorption, it may contain some water.

Next, for example, sodium hydroxide and an iron source material are weighed so that the molar ratio of sodium to iron (Na / Fe) becomes 1 to 2. Subsequently, for example, after adding the iron source material to the sodium hydroxide so as to cover the sodium hydroxide, the solution is heated at 300 ° C. to 700 ° C. for 5 hours to 7 hours.
The mixture is calcined for 2 hours to cause a solid phase reaction to produce a precursor, α-sodium ferrite. Preferably, from 300 ° C to 4
After calcination at 00 ° C. for 12 to 72 hours, pulverized, and further baked at 400 ° C. to 550 ° C. for 12 hours to 72 hours to obtain α
Forming sodium ferrite; In the present embodiment, the sodium hydroxide is subjected to a solid-phase reaction with the iron source material as it is in a granular state, and is not dissolved in water as in the conventional case.
Α-Sodium ferrite can be easily obtained.

Α-sodium ferrite is represented by the chemical formula shown in Chemical formula 2 if it has a stoichiometric composition.
Not limited to stoichiometric composition. The α-sodium ferrite obtained by this method has a high orientation, and for example, the integrated intensity ratio of the (003) diffraction peak to the (104) diffraction peak obtained by the powder X-ray diffraction method becomes large. ing.

[0026]

Embedded image α-NaFeO ₂

After the formation of the α-sodium ferrite, the α-sodium ferrite is ion-exchanged, for example, by melting at 130 ° C. to 300 ° C. together with the inorganic lithium salt. Examples of the inorganic lithium salt include lithium chloride (LiCl), lithium fluoride (LiF), lithium iodide (LiI), lithium bromide (LiBr), lithium hydroxide (LiOH), lithium nitrate (LiNO ₃ ), and water thereof. The hydrate is preferable, and it is preferable to use one or more of them.
Thereafter, the melt is cooled, filtered with a non-aqueous solvent and dried. Non-aqueous solvents include methanol, ethanol,
Propanol, acetone or hexane is preferred,
It is preferable to use any one of these or a mixture of two or more thereof. Thereby, the cadmium chloride-type lithium ferrite according to the present embodiment is obtained.

This cadmium chloride type lithium ferrite is suitably used, for example, as a cathode material for the following secondary batteries.

FIG. 1 shows a sectional structure of a secondary battery using cadmium chloride type lithium ferrite as a cathode material according to the present embodiment. This secondary battery is a so-called coin type. A disc-shaped positive electrode 12 housed in an outer can 11 and a disc-shaped negative electrode 14 housed in an outer cup 13 are interposed via a separator 15. It is what was laminated. The interiors of the outer can 11 and the outer cup 13 are filled with an electrolytic solution 16 which is a liquid electrolyte, and the periphery of the outer can 11 and the outer cup 13 are hermetically sealed by being caulked via an insulating gasket 17. I have.

The outer can 11 and the outer cup 13 are each made of a metal such as stainless steel or aluminum (Al). Outer can 11 is positive electrode 1
2, and the outer cup 13 functions as a current collector of the negative electrode 14.

The positive electrode 12 contains, for example, the cadmium chloride type lithium ferrite according to the present embodiment as a positive electrode material. As described above, this cadmium chloride-type lithium ferrite has high orientation and high crystallinity. Further, the positive electrode 12 further contains a conductive agent such as carbon black or graphite, and a binder such as polyvinylidene fluoride.

The positive electrode 12 is manufactured by, for example, preparing a positive electrode mixture by mixing a positive electrode material, a conductive agent and a binder, and then compressing and molding the positive electrode mixture into a pellet shape. . In addition to the positive electrode material, the conductive agent and the binder, N, N-dimethylformamide (N, N
A solvent such as -Dimetylformamide (DMF) or N-methylpyrrolidone may be added and mixed to prepare a positive electrode mixture, and the positive electrode mixture may be dried and then compression-molded. At this time, the positive electrode material may be used as it is or may be used after being dried. However, it is preferable that the positive electrode material is sufficiently dried because it reacts with water and impairs the function as the positive electrode material.

The negative electrode 14 includes, for example, one or more of lithium metal, a lithium alloy, and a material capable of inserting and extracting lithium. Materials capable of inserting and extracting lithium include, for example, carbonaceous materials, metal compounds, silicon,
A silicon compound or a conductive polymer may be used, and one or more of these may be used in combination.
Examples of the carbonaceous material include graphite, non-graphitizable carbon, and easily graphitizable carbon.
An oxide such as SiO ₃ or SnO ₂ is mentioned, and a conductive polymer is polyacetylene or polypyrrole. Above all, a carbonaceous material is preferable because a change in crystal structure that occurs during charge and discharge is very small, a high charge and discharge capacity can be obtained, and good cycle characteristics can be obtained.

When the negative electrode 14 contains a material capable of inserting and extracting lithium, the negative electrode 14 is formed with a binder such as polyvinylidene fluoride. In this case, the negative electrode 14 is manufactured by, for example, mixing a material capable of inserting and extracting lithium and a binder to prepare a negative electrode mixture, and then compression-molding the obtained negative electrode mixture into a pellet shape. You. Further, in addition to a material and a binder capable of inserting and extracting lithium, a negative electrode mixture is prepared by adding and mixing a solvent such as N, N-dimethylformamide or N-methylpyrrolidone. After drying, compression molding may be performed.

The separator 15 separates the positive electrode 12 and the negative electrode 14 from each other, and prevents a current short circuit due to contact between the two electrodes.
It allows lithium ions to pass through. The separator 15 is made of, for example, a synthetic resin porous film made of polytetrafluoroethylene, polypropylene, polyethylene, or the like, or a porous film made of an inorganic material such as a ceramic nonwoven fabric.
It may have a structure in which a plurality of kinds of porous films are laminated.

The electrolytic solution 16 is used as an electrolyte salt in a solvent.
Lithium salt is ionized
Thereby, it shows ion conductivity. Lichi
Lithium salt is LiPF₆, LiClO_Four, LiAs
F₆, LiBF_Four, LiCF _ThreeSO_Three, LiN (CF_Three
SO_Two)_TwoAlternatively, LiC (CF_ThreeSO_Two)_ThreeIs suitable
Any one or more of these
Are used as a mixture.

As the solvent, propylene carbonate,
Ethylene carbonate, butylene carbonate, vinylene carbonate, γ-butyrolactone, sulfolane,
1,2-dimethoxyethane, 1,2-diethoxyethane, 2-methyltetrahydrofuran, 3-methyl-1,
3-dioxolane, methyl propionate, methyl butyrate,
Non-aqueous solvents such as dimethyl carbonate, diethyl carbonate and dipropyl carbonate are preferred, and one or more of these are used in combination.

This secondary battery operates as follows.

In this secondary battery, when charged, for example, lithium ions are released from the positive electrode 12 and the electrolyte 16
Through the negative electrode 14. When discharging is performed, for example, lithium ions are released from the negative electrode 14 and the electrolyte 16
Through the positive electrode 12. Here, since the positive electrode 12 contains the cadmium chloride-type lithium ferrite according to the present embodiment, the orientation or crystallinity of the cadmium chloride-type lithium ferrite is high, and the conventional cadmium chloride-type lithium ferrite is used. A larger charging capacity can be obtained as compared with the case where the battery is used.

As described above, according to the cadmium chloride type lithium ferrite according to the present embodiment, (00) with respect to the diffraction peak of (104) obtained by the powder X-ray diffraction method.
3) the integrated intensity ratio of the diffraction peak of 2.5 or more, or
Since the half width of the diffraction peak of (003) is 0.45 or less, excellent characteristics can be obtained. For example, when used as a positive electrode material of a battery, a high charge capacity can be obtained.

Further, according to the method for producing cadmium chloride-type lithium ferrite according to the present embodiment, sodium hydroxide is allowed to undergo a solid-phase reaction with at least one of the group consisting of iron compounds and metallic iron. Therefore, α-sodium ferrite can be easily produced at low cost. Therefore, the cadmium chloride-type lithium ferrite according to the present embodiment can be easily mass-produced at low cost.

[0042]

EXAMPLES Further, specific examples of the present invention will be described in detail.

First, 1.3 g of granular sodium hydroxide as a sodium source material was put into a crucible, and γ-iron oxyhydroxide (III) (γ-FeOOH) as an iron source material was covered so as to cover the sodium hydroxide. 2.7 g)
Calcination was performed at 350 ° C. for 24 hours. Next, the calcined product was pulverized and calcined at 500 ° C. for 24 hours to obtain a powdery precursor product. When the obtained precursor product was analyzed by powder X-ray diffraction, it was found that the precursor product was a single phase of α-sodium ferrite. FIG. 2 shows the powder X-ray diffraction pattern.

Next, the precursor product and lithium nitrate were mixed at a mass ratio of precursor product: lithium nitrate = 1: 5. Subsequently, the mixture was subjected to ion exchange by heating at 260 ° C. for 4 hours in an argon atmosphere, cooled, filtered with methanol, and dried to obtain a powdery final product. This final product was also analyzed by powder X-ray diffraction.
No residual sodium ferrite was observed, and all diffraction peaks could be indexed by hexagonal cadmium chloride-type lithium ferrite unit cells. FIG. 2 also shows the powder X-ray diffraction pattern.

In the powder X-ray diffraction patterns of the precursor product and the final product, both orientations were observed.
The integral intensity ratio of the diffraction peak of (003) to the diffraction peak of was 2.71 for the precursor product, and 6.50 for the final product.
Met. The half width of the diffraction peak of (003) for the final product was 0.425.
Table 1 shows the results.

[0046]

[Table 1]

As a comparative example with respect to the example, a final product was produced in the same manner as in the example except that the method of producing the precursor product was changed. As the precursor product, sodium peroxide was used as a sodium source material, and α-iron oxide (III) (α-Fe ₂ O ₃ ) was used as an iron source material. III) = 1: 1 after mixing at a molar ratio, followed by firing in an oxygen atmosphere at 500 ° C for 27 hours.

As for the comparative examples, the precursor product and the final product were analyzed by powder X-ray diffraction.
As a result, as in the example, the precursor product was a single phase of α-sodium ferrite, the residual α-sodium ferrite was not observed in the final product, and all diffraction peaks of the final product were The index could be indexed by unit cells of hexagonal cadmium chloride-type lithium ferrite. FIG.
2 shows the powder X-ray diffraction pattern.

In the same manner as in the examples, for the precursor product and the final product, the integrated intensity ratio of the diffraction peak of (003) to the diffraction peak of (104) was determined.
The half width of the diffraction peak of (003) was determined for the final product. Table 1 also shows the results.

As can be seen from FIG. 2 and Table 1, the example is different from the comparative example in that both the α-sodium ferrite as the precursor product and the cadmium chloride type lithium ferrite as the final product are (104) The integral intensity ratio of the (003) diffraction peak to the diffraction peak was large. That is, according to the examples, it was found that α-sodium ferrite having high orientation was obtained, and thereby cadmium chloride-type lithium ferrite having high orientation was obtained.

Further, the half-width of the diffraction peak of (003) of the cadmium chloride type lithium ferrite, which is the final product, was smaller in the example than in the comparative example. That is, according to the example, it was found that a cadmium chloride type lithium ferrite having high crystallinity could be obtained.

Further, coin-type batteries as shown in FIG. 1 were produced using the obtained cadmium chloride-type lithium ferrites of Examples and Comparative Examples. Here, the description will be given using the reference numerals with reference to FIG.

The positive electrode 12 of the battery was manufactured as follows. First, the prepared cadmium chloride-type lithium ferrite was used as a positive electrode material, and 60% by mass of the positive electrode material, 35% by mass of graphite as a conductive agent, and 5% by mass of polyvinylidene fluoride as a binder were sufficiently mixed in an agate mortar. The mixture was further mixed using N, N-dimethylformamide, and dried under reduced pressure at 100 ° C. for 3 hours or more to obtain a positive electrode mixture. Subsequently, this positive electrode mixture was molded together with a net-like current collector made of aluminum at a pressure of 300 kg / cm ² to obtain a pellet having a diameter of 15 mm, and the pellet was dried at 120 ° C. under reduced pressure. Thereby, the positive electrode 1
2 was obtained.

For the negative electrode 14, lithium metal punched into a disk having a thickness of 1.85 mm and a diameter of 15 mm was used.
As the separator 15, a porous film made of polypropylene was used. The electrolyte 16 contains lithium hexafluorophosphate (LiPF ₆ ) as a lithium salt in a solvent in which ethylene carbonate and dimethyl carbonate are mixed at a volume ratio of 1: 1.
The solution dissolved at a concentration of mol / dm ³ was used. The size of the battery was 20 mm in diameter and 2.5 mm in height. A series of operations from the production of the electrodes to the assembly of the battery were all performed in a dry room at a dew point of −40 ° C.

The charging characteristics of the manufactured batteries were examined, and the characteristics of cadmium chloride-type lithium ferrite as a positive electrode material were evaluated. Charging is performed at a constant current of 0.10 mA until the voltage reaches 4.99 V.
Constant voltage charging was performed at a constant voltage of 4.99 V until the total charging time reached 30 hours. The obtained charging curve is shown in FIG.

As can be seen from FIG. 3, a larger charge capacity was obtained in the example than in the comparative example. That is, the integrated intensity ratio of the (003) diffraction peak to the (104) diffraction peak obtained by the powder X-ray diffraction method is 2.5 or more, or the half width of the (003) diffraction peak is 0.4.
It was found that the capacity can be improved by using cadmium chloride type lithium ferrite of 5 or less.

Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and can be variously modified. For example, in the above embodiments and examples, the case where cadmium chloride type lithium ferrite is included as the positive electrode material has been described. In addition to this cadmium chloride type lithium ferrite, LiCoO ₂ , LiNiO ₂ , and LiMnO ₂ are used.
₂ or another lithium-containing oxide such as LiMn ₂ O ₄ , or lithium sulfide, or a polymer material.

In the above-described embodiment and examples,
Although the description has been given of the case where the electrolytic solution which is a liquid electrolyte is used, another electrolyte may be used. Other electrolytes include, for example, a gel electrolyte in which an electrolyte is held in a polymer compound, an organic solid electrolyte in which an electrolyte salt is dispersed in a polymer compound having ion conductivity, an ion conductive ceramic, and an ion conductive glass. Alternatively, an inorganic solid electrolyte composed of an ionic crystal or the like, a mixture of the inorganic solid electrolyte and the electrolytic solution, or a mixture of the inorganic solid electrolyte and a gel electrolyte or an organic solid electrolyte may be used.

Further, in the above embodiments and examples,
Although a coin-type secondary battery has been specifically described, the present invention relates to a secondary battery having another shape such as a cylindrical type, a button type or a square type, or a secondary type having another structure such as a wound structure. The same can be applied to a secondary battery.

In addition, in the above embodiments and examples, the case where the positive electrode material of the present invention is used for a secondary battery has been described. However, the present invention can be similarly applied to other batteries such as a primary battery.

[0061]

As described above, according to the cadmium chloride type lithium ferrite of the first or second aspect, the diffraction of (003) with respect to the diffraction peak of (104) obtained by the powder X-ray diffraction method. Since the integrated intensity ratio of the peak is 2.5 or more, or the half-width of the diffraction peak of (003) is 0.45 or less, excellent characteristics can be obtained.

Further, any one of claims 3 to 6
According to the method for producing cadmium chloride-type lithium ferrite described in the section, sodium hydroxide and at least one member of the group consisting of iron compounds and metallic iron are allowed to undergo a solid-phase reaction, so that they can be easily manufactured at low cost. α-Sodium ferrite can be produced. Therefore, the cadmium chloride-type lithium ferrite of the present invention can be easily mass-produced at low cost.

Further, according to the battery of the seventh or eighth aspect, since the cadmium chloride-type lithium ferrite of the present invention is used for the positive electrode, the capacity can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a secondary battery using a cadmium chloride-type lithium ferrite as a positive electrode material according to an embodiment of the present invention.

FIG. 2 is an X-ray powder diffraction pattern according to an example of the present invention.

FIG. 3 is a characteristic diagram showing a charging curve according to an example of the present invention.

[Explanation of symbols]

11 ... outer can, 12 ... positive electrode, 13 ... outer cup, 14 ...
Negative electrode, 15: separator, 16: electrolytic solution, 17: gasket

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G002 AA06 AB01 AE05 5H029 AJ01 AK02 AL12 AM02 AM07 BJ03 CJ11 EJ01 EJ04 EJ12 5H050 AA19 BA17 CA02 CB12 EA09 EA23 GA11 HA02 HA13

Claims (8)

[Claims] (1) A powder obtained by powder X-ray diffraction (10
A cadmium chloride-type lithium ferrite, wherein the integrated intensity ratio of the diffraction peak of (003) to the diffraction peak of 4) is 2.5 or more. 2. The powder obtained by powder X-ray diffraction (00
3) A cadmium chloride-type lithium ferrite, wherein the half width of the diffraction peak of 0.4) is 0.45 or less. 3. A step of producing α-sodium ferrite by subjecting sodium hydroxide to at least one kind selected from the group consisting of an iron compound and metallic iron to produce α-sodium ferrite; Producing a cadmium chloride-type lithium ferrite by ion-exchanging the cadmium chloride in an inorganic lithium salt. 4. The solid-state reaction of sodium hydroxide with at least one of the group consisting of a water-soluble iron salt, iron hydroxide, iron oxyhydroxide and metallic iron. Of producing cadmium chloride-type lithium ferrite of the present invention. 5. An inorganic lithium salt comprising lithium chloride,
4. A cadmium chloride-type lithium ferrite according to claim 3, wherein at least one selected from the group consisting of lithium fluoride, lithium iodide, lithium bromide, lithium hydroxide, lithium nitrate and hydrates thereof is used. Manufacturing method. 6. The cadmium chloride type lithium ferrite according to claim 3, wherein at least one non-aqueous solvent selected from the group consisting of methanol, ethanol, propanol, acetone and hexane is used in the ion exchange. Method. 7. A battery provided with a positive electrode containing cadmium chloride type lithium ferrite, wherein the cadmium chloride type lithium ferrite has a (003) diffraction peak with respect to a (104) diffraction peak obtained by a powder X-ray diffraction method. Wherein the integrated intensity ratio is 2.5 or more. 8. A battery provided with a positive electrode containing cadmium chloride-type lithium ferrite, wherein the cadmium chloride-type lithium ferrite has a half width of a diffraction peak of (003) obtained by a powder X-ray diffraction method of 0.3. A battery characterized by being 45 or less.