JP2005108826A - Lithium-containing substance and method of manufacturing non-aqueous electrolyte electrochemical cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing lithium-containing substance possible easily manufacturable in a short time and with low cost, and a method of manufacturing non-aqueous electrolyte electrochemical cell having a large discharge capacity and good high rate electric discharge performance using the lithium-containing substance obtained by the method. <P>SOLUTION: In a method of manufacturing lithium-containing substance, solution made by dissolving metal lithium and polycyclic aromatic compound in chain-like monoether is made to contact with the material containing at least one sort of element chosen from transition metals of the long period periodic table, 13 group metals, 14 group metals and 15 group metals absorb lithium in the material. Further, in a method of manufacturing non-aqueous electrolyte electrochemical cell, the electrode containing the lithium-containing substance obtained by the former method is used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a lithium-containing material and a method for producing a non-aqueous electrolyte electrochemical cell containing the same.

  In recent years, small and lightweight lithium ion secondary batteries have been widely used as power sources for electronic devices such as mobile phones and digital cameras. Since the multi-functionalization of such electronic devices is remarkably advanced, further improvement in the energy density of the battery is expected.

Currently, lithium transition metal oxides are mainly used as positive electrode active materials for lithium ion secondary batteries in practical use, and carbon materials are mainly used as negative electrode active materials. Other positive electrode active material candidates include TiS ₂ , MoS ₂ , MnO ₂ , and V ₂ O ₅ , and these are currently being studied for practical use. However, these positive electrode active materials do not contain lithium that contributes to the charge / discharge reaction. Therefore, in order to produce a lithium ion battery, there is a problem that these positive electrode active materials must be combined with a negative electrode active material containing lithium.

  One example of the negative electrode active material containing lithium is metallic lithium or a lithium alloy, but these cannot be used because of poor cycle performance. Moreover, even when using a carbon material as a negative electrode active material, it was necessary to make this contain lithium beforehand.

In order to produce this lithium-containing carbon material LixC (X> 0), it is disclosed in Patent Document 1 that is charged using an appropriate counter electrode such as metallic lithium in an electrolytic solution containing Li ⁺ ions. There was a need to use an electrochemical method. In this method, an electrode using a carbon material must be prepared in advance and energized. Therefore, a complicated apparatus such as attaching a lead and a device for controlling voltage and current are necessary, and the manufacturing cost is increased.

  Further, LixC (X> 0), like the metal lithium powder, is extremely unstable with respect to moisture and air, and has a problem in handling. Further, the method of directly attaching metallic lithium to the electrode as described in Patent Document 2 has a problem that the process is complicated and time is required.

  On the other hand, if a carbon material not containing lithium can be used as the negative electrode active material, there is no need for an electrochemical method or attachment of metallic lithium to the electrode. However, in this case, the positive electrode active material must contain lithium that contributes to the charge / discharge reaction.

Therefore, in order to obtain a positive electrode active material containing lithium, similarly to the method for producing LixC (X> 0), discharge is performed using an appropriate counter electrode such as a metal lithium plate in an electrolyte containing Li ⁺ ions. There was a need to use an electrochemical method. In this case, there is a problem similar to the electrochemical method which is complicated and takes a long time.

In Patent Document 3 and Patent Document 4, in a cell using a lithium-containing material such as LiCoO ₂ or LiNiO ₂ as a positive electrode and a carbon material as a negative electrode, lithium corresponding to the irreversible capacity of the carbon material is used as these positive electrode active materials. It is described that it occludes chemically to reduce its capacity. However, in these patents, the lithium consumed in the irreversible reaction is supplemented, whereas the use of lithium occluded in the lithium-free material for the charge / discharge reaction of the positive electrode or the negative electrode is not considered. The effect was completely unknown.

  There are other advantages if an easy, short-time, low-cost lithium storage method can be established. Recently, since the utilization factor of the negative electrode using the carbon material has reached the theoretical capacity, it is difficult to improve the discharge capacity of the lithium ion battery in the future. Therefore, active research has been conducted on negative electrode active materials having a large discharge capacity to replace carbon materials.

  As one of the active materials, Patent Document 5 mentions silicon monoxide. However, there is a problem in that the thickness of the battery increases due to the large volume expansion associated with the charging of the electrode using silicon monoxide. In addition, high capacity negative electrode active materials such as tin dioxide, tin monoxide, and zinc monoxide also have a problem of volume expansion accompanying charging.

  One way to solve this problem is to store the lithium in the active material in advance and swell the volume before assembling the battery, so that the degree of swelling of the battery after assembly can be reduced. . For this reason, it is very important to establish an easy, short-time, and low-cost lithium storage method.

JP 2002-075454 A JP 2002-075454 A Japanese Patent No. 3227771 JP-A-8-203525 JP-A-8-130011

There is a demand for a production method for storing lithium that contributes to charge / discharge reaction into a material that does not contain lithium and using it as an active material. In addition, nonaqueous electrolyte electrochemical cells such as batteries and capacitors containing this active material are desired. Further, in a non-aqueous electrolyte electrochemical cell, an electrode using a high-capacity negative electrode active material such as SiO, SnO ₂ , SnO, or ZnO has an unsolved problem that the battery swells due to a large volume expansion due to charging. It was.

  The present invention provides a lithium-containing material and a method for producing a non-aqueous electrolyte electrochemical cell including the same to solve these problems.

  According to the first aspect of the present invention, there is provided a method for producing a lithium-containing material, a solution in which metallic lithium and a polycyclic aromatic compound are dissolved in a linear monoether, A material (M) containing at least one element selected from a metal and a group 15 metal is brought into contact with the material (M) to store lithium.

  According to a second aspect of the present invention, in the method for producing a lithium-containing material of the first aspect, the chain monoether has an asymmetric molecular structure.

  According to a third aspect of the present invention, in the method for producing a lithium-containing material according to the second aspect, the chain monoether is 1-methoxybutane.

  The invention of claim 4 is the method for producing a lithium-containing material of the invention of claim 1, wherein the polycyclic aromatic compound is at least one of naphthalene, phenanthrene, and anthracene.

The invention according to claim 5 is the method for producing a lithium-containing substance according to claim 1, wherein the material (M) is SiO, GeO, GeO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb. _{2 O 3, Sb 2 O 4} , Sb 2 O 5, Bi 2 O 3, Bi 2 O 4, Bi 2 O 5, SnO, SnO 2, SnSi 0.01 O 1.09, SnGe 0.01 O 1. _{09, SnPb 0.01 O 1.09, SnP} 0.01 O 1.09, SnB 2 O 4, SnSiAl 0.2 P 0.2 O 0.3, In 2 O 3, Tl 2 O, Tl 2 O _{3, SnS, SnS 2, GeS} , GeS 2, Sb 2 S 5, Si 3 N 4, AlN, CoO, Co 3 O 4, Co 2 O 3, NiO, TiO 2, TiO, MnO, CuO, Cu 2 O , ZnO, C _{S, Mn 3 P, Co 3} P, Fe 3 P, As 2 O 3, V 2 O 3, V 2 O 4, V 2 O 5, CrO 3, Cr 2 O 3, Mn 2 O 3, Mn 3 O ₄ , at least one selected from MnO ₂ , Fe ₃ O ₄ , Fe ₂ O ₃ , FeO, FeS ₂ , CoS ₂ , TiS ₂ , FePO ₄ , CoPO ₄ , MnPO ₄ , NiF ₃ , and CoF ₃ It is characterized by.

  The invention of claim 6 is the method for producing a lithium-containing substance of the invention of claim 5, wherein the material (M) is SiO.

The invention of claim 7 is the method for producing a lithium-containing substance of the invention of claim 5, wherein the material (M) is at least one selected from FePO ₄ , CoPO ₄ , and MnPO ₄ .

  The invention of claim 8 is characterized in that, in the method for producing a non-aqueous electrolyte electrochemical cell, an electrode containing a lithium-containing substance obtained by the production method of claims 1 to 7 is used.

  According to the present invention, an easy, short-time, low-cost lithium-free material (M) is brought into contact with a solution obtained by dissolving metallic lithium and a polycyclic aromatic compound in a chain monoether. A method for producing a lithium-containing material, in which lithium is occluded in M), can be provided. Moreover, the manufacturing method of the nonaqueous electrolyte electrochemical cell which shows a large discharge capacity and favorable high-rate discharge performance can be provided by using the substance which contained lithium in the material (M) for an active material.

  The method for producing a lithium-containing substance of the present invention comprises a solution in which metallic lithium and a polycyclic aromatic compound are dissolved in a chain monoether (hereinafter abbreviated as “solution S”), a transition metal of a long-period periodic table, A material M containing at least one selected from the group elements Si, Ge, Sn, Pb, As, Sb, Bi (hereinafter abbreviated as “material M”) is made to occlude lithium in the material M .

  Furthermore, a non-aqueous electrolyte electrochemical cell such as a battery or a capacitor is provided with an electrode containing a lithium-containing substance obtained by the production method of the present invention.

  Since the lithium-containing substance obtained by bringing the material M and the solution S into contact with each other can electrochemically occlude and release lithium, a non-aqueous electrolyte electrochemical cell can be formed by using an electrode including the lithium. Can be produced.

  The elements contained in the material M include Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Nb, Si, Ge, Sn, and Pb because the charge / discharge characteristics of the nonaqueous electrolyte electrochemical cell are good. And Sb are preferably used. Further, Mn, Fe, Co, and Si are preferable.

  Either the electrode may be produced after the material M is brought into contact with the solution S, or the electrode and the solution S may be brought into contact after the electrode is produced.

  When metallic lithium and a polycyclic aromatic compound are dissolved in a chain monoether, electrons move from the metallic lithium to the polycyclic aromatic compound to form anions and lithium ions to form a complex solution. Accordingly, when all of the metallic lithium is dissolved in the solution S, it contains lithium ions, polycyclic aromatic compounds, anions of polycyclic aromatic compounds, and solvents. When only a part of metallic lithium is dissolved, it contains metallic lithium, lithium ions, polycyclic aromatic compounds, anions of polycyclic aromatic compounds, and solvents. Next, electrons move from the anion of the polycyclic aromatic compound to the material M, and at the same time, lithium ions are occluded in the material M. At this time, since the anion of the polycyclic aromatic compound returns to the polycyclic aromatic compound, it has a catalytic role in the lithium occlusion reaction.

In the solution S, the lithium concentration is preferably in the range from 0.07 g / dm ³ to saturation. When the concentration is smaller than 0.07 g / dm ^3, there arises a problem that the storage time becomes long. In order to shorten the storage time, it is more preferable to saturate the lithium concentration.

Further, the concentration of the polycyclic aromatic compound in the solution S is preferably 0.005 to 2.0 mol / dm ³ . More preferably, it is 0.005-0.25 mol / dm < ³ >, More preferably, it is 0.005-0.01 mol / dm < ³ >. When the concentration of the polycyclic aromatic compound is less than 0.005 mol / dm ³ , there arises a problem that the occlusion time becomes long. On the other hand, when the concentration is larger than 2.0 mol / dm ³ , there arises a problem that the polycyclic aromatic compound is precipitated in the solution.

  The time for bringing the solution S and the material M into contact is not particularly limited. However, in order to fully occlude lithium in the material M, 0.5 minute or more is necessary, 0.5 minutes to 240 hours are preferable, and 0.5 minutes to 72 hours are more preferable.

  In addition, when the material M is immersed in the solution S, the occlusion speed of lithium can be increased by stirring the solution S. Further, although the occlusion speed can be increased by increasing the temperature of the solution S, it is preferable to set the temperature below the boiling point of the chain monoether so as not to boil the solution.

The material M to be used in the present _{invention, GeO, GeO 2, PbO,} PbO 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, Bi 2 O 3, Bi ₂ O ₄ , Bi ₂ O ₅ , SnO, SnO ₂ , SnSi _0.01 O _1.09 , SnGe _0.01 O _1.09 , SnPb _0.01 O _1.09 , SnP _0.01 O _1.09 , SnB ₂ O ₄ , SnSiAl _0.2 P _0.2 O _0.3 , In ₂ O ₃ , oxides such as Tl ₂ O, Tl ₂ O ₃ , As ₂ O ₃ , SnS, SnS ₂ , GeS, GeS ₂ At least selected from Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb and Bi, such as sulfides such as Sb ₂ S ₅ , nitrides such as Si ₃ N ₄ , AlN Containing one element Compounds, or these compounds include typical non-metallic elements such as N, P, F, Cl, Br, I, and S, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Examples include substances containing at least one selected from transition metal elements such as Ta, Hf, Nb, and W.

Among these, an oxide represented by SiO _x (0 ≦ x <2) is more preferable because it can contribute to an improvement in energy density. Typical non-metallic elements such as N, P, F, Cl, Br, I, and S, typical metallic elements such as Mg, Al, Ca, Ga, Ge, Sn, Pb, and Bi, Sc, Ti, and V , Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, and W may be included.

Incidentally, in the oxide represented by _{SiO x (0 ≦ x <2} ) , it is preferable to use a material containing both phases of SiO ₂ and Si. Furthermore, in X-ray diffraction analysis using CuKα rays, it is preferable that B <3 °, where B is the half width of the main diffraction peak (2θ) appearing in the range of 46 ° to 49 °.

Furthermore, as the material M used in the present invention, CoO, Co ₃ O ₄ , Co ₂ O ₃ , CoPO ₄ , NiO, TiO ₂ , TiO, V ₂ O ₃ , V ₂ O ₄ , V ₂ O ₅ , CrO ₃ , At least one transition metal selected from Cr ₂ O ₃ , MnO, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , FeO, Fe ₂ O ₃ , Fe ₃ O ₄ , CuO, Cu ₂ O, ZnO and the like. Oxides, fluorides such as CoF ₃ , NiF ₃ , sulfides such as TiS ₂ , FeS ₂ , CoS, nitrides such as Fe ₃ N, phosphides such as Mn ₃ P, Co ₃ P, Fe ₃ P, or These compounds contain at least one of typical non-metallic elements such as B, N, P, F, Cl, Br, and I, and typical metallic elements such as Mg, Al, Ca, Ga, Ge, Sn, Pb, and Bi. Substances to be mentioned .

  These materials M can be used alone or in admixture of two or more. Moreover, it can be used from high crystallinity to amorphous. Further, the form can be used in the form of powder, film, fiber, porous body and the like.

  The material M can be used by forming a composite with a carbon material. As this composite, the surface of the material M coated with a carbon material, the material M mixed with the carbon material and granulated, and the surface of the particle granulated by mixing the material M and the carbon material Examples thereof include those coated with a carbon material.

  As a method of coating with a carbon material, a CVD method in which benzene, toluene, xylene, methane, ethane, propane, butane, ethylene or acetylene is decomposed in a gas phase using a carbon source and chemically deposited on the surface of the particles, It can be produced by a method of firing after mixing with a thermoplastic resin such as pitch, tar or furfuryl alcohol, or a method using a mechanical reaction between particles and a carbon material. Of these, the CVD method is preferably used because the carbon material can be uniformly coated.

  The electrode containing the lithium-containing material of the present invention can be used for only the positive electrode of the nonaqueous electrolyte electrochemical cell, only the negative electrode, or both the positive electrode and the negative electrode.

  When an electrode containing a lithium-containing material is used only for the positive electrode of a nonaqueous electrolyte electrochemical cell, the negative electrode active material is not particularly limited, and carbon materials such as graphite and amorphous carbon, oxides, nitrides, etc. Various materials can be used.

  When an electrode containing a lithium-containing material is used only for the negative electrode of a non-aqueous electrolyte electrochemical cell, the positive electrode active material is not particularly limited, and transition metal oxides such as manganese dioxide and vanadium pentoxide, iron sulfide, Various materials such as transition metal chalcogen compounds such as titanium sulfide and carbon materials such as activated carbon and graphite can be used.

  The binder used when producing the positive and negative electrodes is ethylene-propylene-diene terpolymer, acrylonitrile-butadiene rubber, fluororubber, polyvinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, polyfluoride. Selected from vinylidene, polyethylene, polypropylene, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, styrene-butadiene rubber (SBR) or carboxymethylcellulose (CMC) At least one of the above can be used.

  As the solvent used when mixing the binder, either a non-aqueous solvent or an aqueous solution can be used. Non-aqueous solvents include N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran, etc. Can do. On the other hand, what added a dispersing agent, a thickener, etc. can be used for aqueous solution.

  As the current collector of the electrode, iron, copper, stainless steel, nickel, or aluminum can be used. Examples of the shape include a sheet, a foam, a mesh, a porous body, and an expanded lattice. Further, a current collector having a hole in an arbitrary shape can be used.

  Organic solvents used in the electrolyte include ethylene carbonate, propylene carbonate, butylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, sulfolane, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyl Non-aqueous solvents such as tetrahydrofuran, 3-methyl-1,3-dioxolane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methyl propyl carbonate, etc. Or a mixed solvent thereof can be used. In addition, carbonate-based compounds such as vinylene carbonate and butylene carbonate, benzene-based compounds such as biphenyl and cyclohexylbenzene, and sulfur-based compounds such as propane sultone can be used alone or in combination in the electrolytic solution.

Furthermore, it can be used in combination with an electrolytic solution and a solid electrolyte. As the solid electrolyte, a crystalline or amorphous inorganic solid electrolyte can be used. The former includes LiI, Li ₃ N, Li _{1 + x} M _x Ti _2-x (PO ₄ ) ₃ (M = Al, Sc, Y, La), Li _0.5-3x R _{0.5 + x} TiO ₃ (R = La, Pr, Nd, Sm), or thio LISICON represented by Li _4-x Ge _1-x P _x S ₄ can be used, the latter being LiI-Li ₂ O—B ₂ O ₅ system, Li _{A 2} O—SiO ₂ system, a LiI—Li ₂ S—B ₂ S ₃ system, a LiI—Li ₂ S—SiS ₂ system, a Li ₂ S—SiS ₂ —Li ₃ PO ₄ system, or the like can be used.

Examples of the salt dissolved in the organic solvent include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF (CF ₃ ) ₅ , LiPF ₂ (CF ₃ ) ₄ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , LiPF ₅ (CF ₃ ), LiPF ₃ (C ₂ F ₅ ) ₃ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , LiN (COCF ₃ ) ₂ , LiN (COCF ₂ CF ₃ ) ₂ , LiC ₄ BO ₈ or the like can be used alone or a mixture thereof. Among them, since the cycle performance is improved, as the lithium salt, LiPF ₆ is preferred. Furthermore, the concentration of these lithium salts is preferably in the range of 0.5 to 2.0 mol / dm ³ .

  Examples of the separator for the non-aqueous electrolyte electrochemical cell include microporous membranes such as nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, and polyolefin.

  The shape of the nonaqueous electrolyte electrochemical cell is not particularly limited, and various shapes such as a square shape, an oval shape, a coin shape, a button shape, and a sheet shape battery can be used.

  Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples.

[Example 1, Comparative Examples 1 and 2]
[Example 1]
As the material M, FePO ₄ powder having a number average particle diameter of 80 nm was used. First, 75% by mass of FePO ₄ , 5% by mass of acetylene black (AB) as a conductive agent and 20% by mass of polyvinylidene fluoride (PVDF) as a binder were added in N-methyl-2-pyrrolidone (NMP). A paste was prepared by mixing. Next, this paste was applied on both surfaces of an aluminum foil having a thickness of 20 μm and vacuum-dried at 150 ° C. Furthermore, both surfaces were compression-molded with a roll press to produce an electrode containing FePO ₄ .

Furthermore, this electrode was immersed in a solution S1 in which naphthalene having a concentration of 0.25 mol / dm ³ and a saturated amount of metal Li were dissolved in diethyl ether (DEE) solvent at 25 ° C. for 3 days, and LiPO ₄ was dissolved in LiPO ₄ . Occluded. Finally, this electrode was washed with dimethyl carbonate and dried to obtain an electrode A1 containing FePO ₄ storing Li.

  A paste was prepared by mixing 92% by mass of natural graphite and 8% by mass of PVDF in NMP. Next, this paste was applied on both sides of a copper foil having a thickness of 15 μm and vacuum-dried at 150 ° C. Furthermore, both surfaces were compression-molded with a roll press to obtain an electrode G0 containing natural graphite.

A positive electrode A1, a negative electrode B0, and a polyethylene separator having a thickness of 20 μm and a porosity of 40% were overlapped and wound, and inserted into a rectangular container having a height of 48 mm, a width of 30 mm, and a thickness of 4.2 mm. Next, a nonaqueous electrolytic solution in which 1 mol / dm ³ of LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 1: 1 was injected into the container. A non-aqueous electrolyte electrochemical cell produced by the production method of Example 1 was obtained.

[Comparative Example 1]
The nonaqueous electrolyte electrochemical cell of Comparative Example 1 was prepared in the same manner as in Example 1 except that a solution (T1) in which a saturated amount of n-butyllithium was dissolved in diethyl ether (DEE) was used instead of S1 as the solution S. Obtained.

[Comparative Example 2]
The same procedure as in Example 1 was used except that instead of S1, a solution (T2) in which naphthalene having a concentration of 0.25 mol / dm ³ and a saturated amount of LiPF ₆ were dissolved in diethyl ether (DEE) solvent was used as solution S. A nonaqueous electrolyte electrochemical cell of Comparative Example 2 was obtained.

[Electrochemical test]
Each battery is charged at 4.5 ° C. with a constant current of 450 mA (1 CmA) at 25 ° C. and further charged with a constant voltage of 4.5 V for 2 hours, and then discharged to 0.5 V with a constant current of 450 mA (1 CmA). The discharge capacity (1 CmA) was measured.

  Next, at 25 ° C., each battery was charged with a constant current of 450 mA (1 CmA) to 4.5 V, and further charged with a constant voltage of 4.5 V for 2 hours, and subsequently, 0.5 V with a constant current of 4500 mA (10 CmA). Discharged until. The discharge capacity ratio (%) at 4500 mA constant current to the discharge capacity at 450 mA constant current was calculated.

Table 1 shows the test results of the nonaqueous electrolyte electrochemical cells obtained by the production methods of Example 1, Comparative Example 1 and Comparative Example 2.

  From the results in Table 1, the following became clear. The non-aqueous electrolyte electrochemical cell of Example 1 using metal Li and naphthalene as the polycyclic aromatic compound in the solution S was more discharged than the non-aqueous electrolyte electrochemical cell of Comparative Example 1 using n-butyllithium. And the high rate discharge performance was excellent.

The reason for this is that when T1 is used in the solution S, impurities such as an n-butyl group-derived alkane polymer are produced when lithium moves from Fe-B ₄ to n-butyl lithium, and these are washed with dimethyl carbonate. It is presumed that the discharge capacity of the battery and the high-rate discharge performance were lowered due to remaining without being removed in the process.

On the other hand, the lithium storage mechanism when the solution S1 is used is considered as follows. First, electrons move from metallic lithium to naphthalene to form a complex solution in which naphthalene anions and lithium ions are dissolved. Then naphthalene anion, lithium ions are inserted in the FePO ₄ after electrons have moved to the FePO _4. At this time, the naphthalene anion returns to naphthalene and has a catalytic role in the lithium storage reaction. Even after the electrons move from the naphthalene anion to FePO ₄ , no polymerization reaction occurs when n-butyllithium is used, so no impurities are generated.

Further, when T2 is used for the solution S, the storage of Li hardly occurs. This is because even if LiPF ₆ is used instead of metal Li, a naphthalene anion is not generated. Therefore, the discharge capacity of the nonaqueous electrolyte electrochemical cell of Comparative Example 2 is extremely small.

  Polycyclic aromatic compounds such as anthracene, phenanthrene, 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 2-fluoronaphthalene, 2-ethylnaphthalene, naphthacene, pentacene, pyrene, picene, triphenylene, anthanthrene, acenaphthene The same effect was obtained when acenaphthylene, benzopyrene, benzofluorene, benzophenanthrene, benzofluoroanicene, benzoperylene, coronene, chrysene, and hexabenzoperylene were used.

[Examples 2 to 16, Comparative Examples 3 to 14]
[Example 2]
A nonaqueous electrolyte electrochemical cell of Example 2 was produced in the same procedure as Example 1 except that 1-methoxypropane (1-MP) was used instead of diethyl ether.

[Example 3]
A nonaqueous electrolyte electrochemical cell of Example 3 was produced in the same procedure as in Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether.

[Example 4]
A nonaqueous electrolyte electrochemical cell of Example 4 was produced in the same procedure as Example 1 except that 1-methoxypentane (1-MPE) was used instead of diethyl ether.

[Example 5]
A nonaqueous electrolyte electrochemical cell of Example 5 was produced in the same procedure as Example 1 except that 2-methoxybutane (2-MB) was used instead of diethyl ether.

[Example 6]
A non-aqueous electrolyte electrochemical cell of Example 6 was produced in the same procedure as Example 1 except that isobutyl methyl ether (i-BME) was used instead of diethyl ether.

[Example 7]
A nonaqueous electrolyte electrochemical cell of Example 7 was prepared in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Example 8]
A nonaqueous electrolyte electrochemical cell of Example 8 was prepared in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Example 9]
Instead of 1-methoxy-butane in diethyl ether (1-MB), except for using CoPO ₄ instead of FePO ₄ was used to fabricate a non-aqueous electrolyte electrochemical cell of Example 9 in the same manner as in Example 1.

[Example 10]
Instead of 1-methoxy-butane in diethyl ether (1-MB), except for using MnPO ₄ instead of FePO ₄ was used to fabricate a non-aqueous electrolyte electrochemical cell of Example 10 in the same manner as in Example 1.

[Example 11]
A nonaqueous electrolyte electrochemical cell of Example 11 was prepared in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and Fe ₂ O ₃ was used instead of FePO _4. did.

[Example 12]
A nonaqueous electrolyte electrochemical cell of Example 12 was produced in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and FeO was used instead of FePO ₄ .

[Example 13]
A nonaqueous electrolyte electrochemical cell of Example 13 was prepared in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and V ₂ O ₅ was used instead of FePO _4. did.

[Example 14]
A nonaqueous electrolyte electrochemical cell of Example 14 was produced in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and MnO ₂ was used instead of FePO ₄ .

[Example 15]
A nonaqueous electrolyte electrochemical cell of Example 15 was produced in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and TiS ₂ was used instead of FePO ₄ .

[Example 16]
A nonaqueous electrolyte electrochemical cell of Example 16 was produced in the same procedure as Example 1 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and CoF ₃ was used instead of FePO ₄ .

[Comparative Example 3]
A nonaqueous electrolyte electrochemical cell of Comparative Example 3 was produced in the same procedure as Example 1 except that tetrahydrofuran (THF) was used instead of diethyl ether.

[Comparative Example 4]
A nonaqueous electrolyte electrochemical cell of Comparative Example 4 was produced in the same procedure as Example 1 except that tetrahydrofuran (THF) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 5]
A nonaqueous electrolyte electrochemical cell of Comparative Example 5 was produced in the same procedure as Example 1 except that tetrahydrofuran (THF) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 6]
A nonaqueous electrolyte electrochemical cell of Comparative Example 6 was produced in the same procedure as in Example 1 except that hexane (HS) was used instead of diethyl ether.

[Comparative Example 7]
A nonaqueous electrolyte electrochemical cell of Comparative Example 7 was produced in the same procedure as Example 1 except that hexane (HS) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 8]
A nonaqueous electrolyte electrochemical cell of Comparative Example 8 was produced in the same procedure as Example 1 except that hexane (HS) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 9]
A nonaqueous electrolyte electrochemical cell of Comparative Example 9 was produced in the same procedure as Example 1 except that dimethoxyethane (DME) was used instead of diethyl ether.

[Comparative Example 10]
A nonaqueous electrolyte electrochemical cell of Comparative Example 10 was prepared in the same procedure as Example 1 except that dimethoxyethane (DME) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 11]
A nonaqueous electrolyte electrochemical cell of Comparative Example 11 was prepared in the same procedure as Example 1 except that dimethoxyethane (DME) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 12]
The CoPO ₄ instead of FePO _4, except for using tetrahydrofuran (THF) in place of diethyl ether was used to fabricate a non-aqueous electrolyte electrochemical cell of Comparative Example 12 in the same manner as in Example 1.

[Comparative Example 13]
The CoPO ₄ instead of FePO _4, except for using hexane (HS) in place of diethyl ether was used to fabricate a non-aqueous electrolyte electrochemical cell of Comparative Example 13 in the same manner as in Example 1.

[Comparative Example 14]
The CoPO ₄ instead of FePO _4, to prepare Comparative Example 14 a non-aqueous electrolyte electrochemical cell in the same manner as in Example 1 except for using dimethoxyethane (DME) in place of diethyl ether.

  Table 2 shows the test results of the non-aqueous electrolyte electrochemical cells of Examples 1 to 16 and Table 3 of Comparative Examples 3 to 14.

  From the results of Tables 2 and 3, the following became clear. Non-aqueous solutions of Comparative Examples 3 to 5 and Comparative Example 12 using cyclic ether in Solution S, Comparative Examples 6 to 8 and Comparative Example 13 using alkane, and Comparative Examples 9 to 11 and Comparative Example 14 using chain diether Compared with the electrolyte electrochemical cell, it was found that the nonaqueous electrolyte electrochemical cells of Examples 1 to 16 using a chain monoether exhibited a large discharge capacity and excellent high rate discharge performance.

  Although the reason is not clear, the non-aqueous electrolyte electrochemical cells of Examples 2 to 6 using a chain monoether having an asymmetric molecular structure are the same as those of Example 1 of a chain monoether having a symmetric molecular structure. Larger discharge capacity and better high rate discharge performance than non-aqueous electrolyte electrochemical cell were shown.

  The same effect is obtained when 2-methoxypentane, 1-methoxyhexane, 2-methoxyhexane, 3-methoxyhexane, 1-ethoxypropane, 1-ethoxybutane, 2-ethoxybutane, and isobutylmethyl ether are used as a solvent. was gotten. The battery using 1-MB showed the largest discharge capacity and good high rate discharge performance.

  Although the reason is not clear, the nonaqueous electrolyte electrochemical cell of Example 3 using naphthalene is more than the nonaqueous electrolyte electrochemical cells of Examples 7 and 8 using other polycyclic aromatic compounds. Furthermore, good high rate discharge performance was shown.

Further, as a material M containing at least one element selected from a transition metal, a group 13 metal, a group 14 metal, and a group 15 metal in the long-period type periodic table, FePO ₄ , CoPO ₄ , MnPO ₄ , and Fe ₂ of this example are used. In addition to O ₃ , FeO, V ₂ O ₅ , MnO ₂ , TiS ₂ , and CoF ₃ , As ₂ O ₃ , V ₂ O ₃ , V ₂ O ₄ , CrO ₃ , Cr ₂ O ₃ , Mn ₂ O ₃ , Similar effects were obtained when Mn ₃ O ₄ , Fe ₃ O ₄ , NiF ₃ , FeS ₂ , and CoS were used.

[Example 17 and Comparative Examples 15 to 17]
[Example 17]
As the material M, SiO which was phase-divided into Si and SiO ₂ was used. In the X-ray diffraction pattern of the CuKα ray of SiO, one of the diffraction peaks (2θ) was in the range of 46 ° to 49 °, and B <3 ° (2θ) when the half width was B. First, a paste was prepared by dispersing 75% by mass of SiO, 5% by mass of acetylene black, and 20% by mass of PVDF in NMP. Next, this paste was applied on both sides of a copper foil having a thickness of 15 μm and vacuum-dried at 150 ° C. Furthermore, both surfaces were compression-molded with a roll press to produce an electrode B0 containing SiO.

Furthermore, this electrode was immersed in a solution S1 in which naphthalene having a concentration of 0.25 mol / dm ³ and a saturated amount of metal Li were dissolved in diethyl ether (DEE) solvent at 25 ° C. for 3 days, and Li was then added to SiO. Occluded. The electrode after immersion was washed with dimethyl carbonate and dried to obtain an electrode B1 containing SiO in which Li was occluded.

A positive electrode A0, a negative electrode B1, and a polyethylene separator having a thickness of 20 μm and a porosity of 40% were overlapped and wound, and inserted into a rectangular container having a height of 48 mm, a width of 30 mm, and a thickness of 4.2 mm. Next, a non-aqueous electrolyte solution in which 1 mol / dm ³ of LiPF ₆ was dissolved in a mixed solvent of EC and EMC in a volume ratio of 1: 1 was poured into this container, and the non-aqueous electrolyte electrochemical cell of Example 17 was injected. Got.

[Comparative Example 15]
LiFePO ₄ was produced by mechanically acting LiOH.H ₂ O, Fe ₂ O ₃ and (NH ₄ ) ₂ HPO ₄ . A paste was prepared by dispersing 75% by mass of LiFePO _4, 5% by mass of acetylene black, and 20% by mass of PVDF in NMP. Next, this paste was applied on both surfaces of an aluminum foil having a thickness of 20 μm and vacuum-dried at 150 ° C. Furthermore, both surfaces were compression-molded with a roll press to produce an electrode containing this LiFePO ₄ .

This LiFePO ₄ electrode for the positive electrode, the electrode B0 for the negative electrode, and a polyethylene separator having a thickness of 20 μm and a porosity of 40% are rolled up and inserted into a rectangular container having a height of 48 mm, a width of 30 mm, and a thickness of 4.2 mm. did. Next, a nonaqueous electrolyte solution in which 1 mol / dm ³ of LiPF ₆ was dissolved in a mixed solvent of EC and EMC in a volume ratio of 1: 1 was injected into this container, and the nonaqueous electrolyte electrochemical cell of Comparative Example 15 was injected. Got.

[Comparative Example 16]
A nonaqueous electrolyte electrochemical cell of Comparative Example 16 was obtained in the same manner as in Example 17 except that a diethyl ether (DEE) solution (T1) in which a saturated amount of n-butyllithium was dissolved instead of S1 was used as the solution S. It was.

[Comparative Example 17]
The same procedure as in Example 17 was used, except that a solution (T2) in which 0.25 mol / dm ³ of naphthalene and a saturated amount of LiPF ₆ were dissolved in diethyl ether (DEE) solvent was used as the solution S instead of S1. A nonaqueous electrolyte electrochemical cell of Comparative Example 17 was obtained.

[Battery thickness test]
Each battery was charged at 4.5 ° C. with a constant current of 450 mA (1 CmA) at 25 ° C. and further with a constant voltage of 4.5 V for 2 hours. The thickness at the center of the battery after charging was measured with a caliper.

  Table 4 shows the test results of the nonaqueous electrolyte electrochemical cells of Example 17 and Comparative Examples 15-17.

  From the results in Table 4, the following became clear. The non-aqueous electrolyte electrochemical cell of Example 17 using SiO as the material M containing at least one element selected from transition metals, group 13 metals, group 14 metals, and group 15 metals of the long-period periodic table has a large discharge. It has been found that it has high capacity and excellent high rate discharge performance. This indicates that this method can be applied to the negative electrode active material.

  Furthermore, the thickness of the non-aqueous electrolyte electrochemical cell of Example 17 in the charged state was smaller than that of Comparative Example 15. From this, it can be considered that by applying this method to the negative electrode, the swelling of the battery due to the volume expansion of SiO accompanying charging is suppressed. Since this method does not require an electrochemical method or the attachment of metallic lithium to the electrode, the process can be simplified and the cost can be reduced.

  The discharge capacity of the nonaqueous electrolyte electrochemical cell of Example 17 using metal Li and naphthalene as the polycyclic aromatic compound in the solution S was larger than that of the nonaqueous electrolyte electrochemical cell of Comparative Example 16 using n-butyllithium. And the high rate discharge performance was excellent. The reason for this is that when T1 is used for the solution S, impurities such as an alkane polymer derived from n-butyl group generated when lithium moves from n-butyllithium to SiO, which are washed with dimethyl carbonate. It is presumed that the discharge capacity of the battery and the high-rate discharge performance were lowered due to remaining without being removed in the process.

Moreover, when T2 is used for the solution S, it is considered that almost no occlusion of Li occurs. This is because even if LiPF ₆ is used instead of metal Li, a naphthalene anion is not generated. Therefore, the discharge capacity of the nonaqueous electrolyte electrochemical cell of Comparative Example 17 is extremely small.

  Polycyclic aromatic compounds such as anthracene, phenanthrene, 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 2-fluoronaphthalene, 2-ethylnaphthalene, naphthacene, pentacene, pyrene, picene, triphenylene, anthanthrene, acenaphthene The same effect was obtained when acenaphthylene, benzopyrene, benzofluorene, benzophenanthrene, benzofluoroanicene, benzoperylene, coronene, chrysene, and hexabenzoperylene were used.

[Examples 18 to 20 and Comparative Examples 18 to 26]
[Example 18]
A nonaqueous electrolyte electrochemical cell of Example 18 was produced in the same procedure as Example 17 except that 1-methoxybutane (1-MB) was used instead of diethyl ether.

[Example 19]
A nonaqueous electrolyte electrochemical cell of Example 19 was produced in the same procedure as Example 17 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Example 20]
A nonaqueous electrolyte electrochemical cell of Example 20 was produced in the same procedure as Example 17 except that 1-methoxybutane (1-MB) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 18]
A nonaqueous electrolyte electrochemical cell of Comparative Example 18 was produced in the same procedure as Example 17 except that tetrahydrofuran (THF) was used instead of diethyl ether.

[Comparative Example 19]
A nonaqueous electrolyte electrochemical cell of Comparative Example 19 was prepared in the same procedure as Example 17 except that tetrahydrofuran (THF) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 20]
A nonaqueous electrolyte electrochemical cell of Comparative Example 20 was produced in the same procedure as Example 17 except that tetrahydrofuran (THF) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 21]
A nonaqueous electrolyte electrochemical cell of Comparative Example 21 was produced in the same procedure as Example 17 except that hexane (HS) was used instead of diethyl ether.

[Comparative Example 22]
A nonaqueous electrolyte electrochemical cell of Comparative Example 22 was produced in the same procedure as Example 17 except that hexane (HS) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 23]
A nonaqueous electrolyte electrochemical cell of Comparative Example 23 was produced in the same procedure as Example 17 except that hexane (HS) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

[Comparative Example 24]
A nonaqueous electrolyte electrochemical cell of Comparative Example 24 was produced in the same procedure as Example 17 except that dimethoxyethane (DME) was used instead of diethyl ether.

[Comparative Example 25]
A nonaqueous electrolyte electrochemical cell of Comparative Example 25 was produced in the same procedure as Example 17 except that dimethoxyethane (DME) was used instead of diethyl ether and anthracene was used instead of naphthalene.

[Comparative Example 26]
A nonaqueous electrolyte electrochemical cell of Comparative Example 26 was produced in the same procedure as Example 17 except that dimethoxyethane (DME) was used instead of diethyl ether and phenanthrene was used instead of naphthalene.

  Table 5 shows the test results of the nonaqueous electrolyte electrochemical cells of Examples 17 to 20 and Comparative Examples 18 to 26.

  From the results in Table 5, the following became clear. Compared with the nonaqueous electrolyte electrochemical cells of Comparative Examples 18 to 20 using cyclic ethers in Solution S, Comparative Examples 21 to 23 using alkanes, and Comparative Examples 24 to 26 using chain diethers, It was found that the non-aqueous electrolyte electrochemical cells of Examples 17 to 20 using ether exhibited large discharge capacity and excellent high rate discharge performance.

  Among them, although the reason is not clear, the non-aqueous electrolyte electrochemical cells of Examples 18 to 20 using a chain monoether having an asymmetric molecular structure are implemented with a chain monoether having a symmetric molecular structure. The discharge capacity was larger than that of the non-aqueous electrolyte electrochemical cell of Example 17, and good high rate discharge performance was exhibited.

  This is the same when 2-methoxypentane, 1-methoxyhexane, 2-methoxyhexane, 3-methoxyhexane, 1-ethoxypropane, 1-ethoxybutane, 2-ethoxybutane, and isobutylmethyl ether are used as solvents. The effect of was obtained. When 1-MB was used, the largest discharge capacity and good high rate discharge performance were shown.

  Moreover, although the reason is not clear, in the comparison of Examples 18 to 20 using the same solvent for the solution S, the nonaqueous electrolyte electrochemical cell of Example 18 using naphthalene uses other polycyclic aromatic compounds. The high-rate discharge performance was better than that of the non-aqueous electrolyte electrochemical cells of Example 19 and Example 20.

Further, as a material M containing at least one element selected from a transition metal, a group 13 metal, a group 14 metal, and a group 15 metal in the long periodic table, GeO, GeO ₂ , PbO, _{PbO 2, Pb 2 O 3,} Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, Bi 2 O 3, Bi 2 O 4, Bi 2 O 5, SnO, SnO 2, SnSi 0 _{.01 O 1.09, SnGe 0.01 O 1.09} , SnPb 0.01 O 1.09, SnP 0.01 O 1.09, SnB 2 O 4, SnSiAl 0.2 P 0.2 O 0. ₃ , In ₂ O ₃ , Tl ₂ O, Tl ₂ O ₃ , SnS, SnS ₂ , GeS, GeS ₂ , Sb ₂ S ₅ , Si ₃ N ₄ , AlN, CoO, Co ₃ O ₄ , Co ₂ O ₃ , NiO, TiO _{2 TiO, MnO, CuO, Cu 2} O, ZnO, CoS, Mn 3 P, Co 3 P, the same effect when using a Fe ₃ P was obtained.

Claims (8)

A solution in which metallic lithium and a polycyclic aromatic compound are dissolved in a chain monoether, and at least one element selected from a transition metal, a group 13 metal, a group 14 metal, and a group 15 metal in the long-period periodic table A method for producing a lithium-containing substance, wherein the material (M) is contacted and lithium is occluded in the material (M). The method for producing a lithium-containing material according to claim 1, wherein the chain monoether has an asymmetric molecular structure. 3. The method for producing a lithium-containing material according to claim 2, wherein the chain monoether is 1-methoxybutane. The method for producing a lithium-containing material according to claim 1, wherein the polycyclic aromatic compound is at least one of naphthalene, phenanthrene, and anthracene. It said material (M) is _{SiO, GeO, GeO 2, PbO} , PbO 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, Bi 2 O 3, Bi 2 O ₄ , Bi ₂ O ₅ , SnO, SnO ₂ , SnSi _0.01 O _1.09 , SnGe _0.01 O _1.09 , SnPb _0.01 O _1.09 , SnP _0.01 O _1.09 , SnB _{2 O 4, SnSiAl 0.2 P 0.2} O 0.3, In 2 O 3, Tl 2 O, Tl 2 O 3, SnS, SnS 2, GeS, GeS 2, Sb 2 S 5, Si 3 N 4 , AlN, CoO, Co ₃ O ₄ , Co ₂ O ₃ , NiO, TiO ₂ , TiO, MnO, CuO, Cu ₂ O, ZnO, CoS, Mn ₃ P, Co ₃ P, Fe ₃ P, As ₂ O ₃ , _{V 2 O} 3, _V 2 _{4, V 2 O 5, CrO} 3, Cr 2 O 3, Mn 2 O 3, Mn 3 O 4, MnO 2, Fe 3 O 4, Fe 2 O 3, FeO, FeS 2, CoS 2, TiS 2, FePO _{4. The} method for producing a lithium-containing material according to claim 1, wherein the method is at least one selected from Co ₄ , CoPO ₄ , MnPO ₄ , NiF ₃ , and CoF ₃ . 6. The method for producing a lithium-containing substance according to claim 5, wherein the material (M) is SiO. 6. The method for producing a lithium-containing material according to claim 5, wherein the material (M) is at least one selected from FePO ₄ , CoPO ₄ , and MnPO ₄ . A method for producing a non-aqueous electrolyte electrochemical cell, comprising using an electrode containing a lithium-containing substance obtained by the production method according to claim 1, 2, 3, 4, 6, or 7.