JP2008226606A - Manufacturing method of lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple manufacturing method of a lithium secondary battery composed by uniformly coating a positive electrode with a conductive polymer. <P>SOLUTION: This manufacturing method of a lithium secondary battery provided with a positive electrode, a negative electrode and an electrolyte is characterized by including: a monomer addition process of including a polymerizable compound being a monomer of a conductive polymer having an electrolytically polymerizable property in the electrolyte; and a polymerization process of polymerizing the polymerizable compound in the positive electrode by imparting potential thereto with the positive electrode brought into contact with the electrolyte. The need of employing a dedicated device executing a process of coating the positive electrode with the conductive polymer is obviated by executing a polymerization reaction with the monomer of the conductive polymer included in the electrolyte. The manufacturing method has an advantage of obviating the need to introduce any additive or any device for the purpose of executing polymerization by employing electrolytic polymerization progressing polymerization by using a difference of potential present in the battery as a polymerization reaction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a lithium secondary battery having a positive electrode whose surface is coated with a conductive polymer.

  With the widespread use of portable electronic devices such as notebook computers, mobile phones, and digital cameras, the demand for secondary batteries that drive these electronic devices is increasing. In recent years, the power consumption of these electronic devices has increased with the progress of higher functionality, and the reduction in size is expected. Therefore, an increase in capacity is required for secondary batteries.

  Among secondary batteries, lithium secondary batteries using a lithium composite oxide such as lithium nickelate as a positive electrode active material and a carbon material such as graphite as a negative electrode active material are considered promising because of their high energy density.

  Since the lithium composite oxide used as the active material of the positive electrode is a substance having extremely low conductivity, the electronic conductivity is ensured by blending a conductive aid such as carbon. However, since carbon as the conductive auxiliary agent is a powder, it can only partially contact the lithium composite oxide as the active material. On the surface of the active material that is not in contact with the conductive auxiliary agent, the efficiency of electron transfer at the time of charge / discharge is reduced, leading to a decrease in capacity and an increase in internal resistance. As a method of increasing the contact between the conductive auxiliary agent and the lithium composite oxide as the active material and ensuring sufficient conductivity, a method of adding a large amount of conductive auxiliary agent is also conceivable, but carbon as the conductive auxiliary agent is a battery reaction. Since the material does not directly participate in (oxidation-reduction reaction), there is a problem that the capacity decreases as the amount of the conductive additive added increases.

  Accordingly, Patent Documents 1 and 2 disclose means for ensuring the conductivity of the surface of the lithium composite oxide, which is a positive electrode active material, using a conductive additive that is active in an oxidation-reduction reaction and functions as an active material. .

  Patent Documents 1 and 2 describe a technique in which polypyrrole powder, which is a conductive polymer, is dispersed on lithium composite oxide particles to adhere to the surface, and pyrrole monomer is oxidized and polymerized using lithium composite oxide as an oxidizing agent to form lithium. A technique for coating the surface of a complex oxide with polypyrrole is disclosed.

  However, in the former method, the polypyrrole powder is dispersed on the lithium composite oxide particles and adhered to the surface. Since both the polypyrrole and lithium composite oxide are powders, it is difficult to uniformly disperse and adhere both, and the effect varies depending on the preparation method. Have the problem of increasing.

  In addition, in the method in which pyrrole monomer is oxidatively polymerized using the latter lithium composite oxide as an oxidant and the surface of the lithium composite oxide is coated with polypyrrole, oxidative polymerization does not proceed depending on the type of lithium composite oxide, and coating is difficult. Has certain drawbacks.

  On the other hand, in Patent Documents 3 and 4, a homogeneous coating liquid prepared by mixing an organic solvent in which polyaniline, which is a conductive polymer having an oxidation-reduction reaction activity, is dissolved, and a lithium composite oxide, is formed into lithium. A method for forming a positive electrode active material layer in which the surface of a composite oxide is coated with polyaniline, and an electropolymerization of an electrolytic solution containing a monomer of a conductive polymer having an activity in an oxidation-reduction reaction, positive electrode active material particles and a conductive auxiliary agent. A technique for producing an electrode in which the surface of active material particles is coated with polyaniline is disclosed.

  However, the coating solution prepared by mixing a lithium composite oxide with an organic solvent in which the polyaniline dissolved in the previous company is formed into a film and the surface of the lithium composite oxide is coated with polyaniline is soluble in an organic solvent such as polyaniline. However, it cannot be applied to conductive polymers that are difficult to solubilize in organic solvents such as polypyrrole and polyacetylene.

In addition, the surface of the positive electrode active material particles is coated with polyaniline by electrolytic polymerization of an electrolyte containing a conductive polymer monomer, particulate active material and conductive auxiliary active in the latter redox reaction. In this method, it is possible to uniformly coat polyaniline on the surface of the lithium composite oxide, but it requires a dedicated facility for performing electropolymerization, which is expensive compared to other methods. was there.
JP 2001-135312 A JP 2001-351634 A JP-A-7-130356 JP-A-9-73893

  Therefore, the present invention solves the above-mentioned problems of the prior art and solves the problem of providing a production method capable of easily producing a lithium secondary battery in which the surface of a lithium composite oxide is uniformly coated with a conductive polymer. To do.

  A method for producing a lithium secondary battery according to the present invention comprises: a positive electrode capable of releasing or storing lithium ions; a negative electrode capable of storing or releasing lithium ions; and an electrolyte solution that moves the lithium ions between the positive electrode and the negative electrode. It is a method of manufacturing a lithium secondary battery provided.

In order to solve the above-mentioned problems, the present inventors diligently studied and completed the following invention. That is, the method for producing a lithium secondary battery of the present invention includes a monomer addition step of containing a polymerizable compound that is a monomer of an electropolymerizable conductive polymer in the electrolytic solution;
And a polymerization step of polymerizing the polymerizable compound at the positive electrode by applying a potential in a state where the positive electrode is in contact with the electrolytic solution.

  By performing the polymerization reaction in a state where the conductive polymer monomer is contained in the electrolytic solution, it is not necessary to employ a dedicated apparatus for performing the step of coating with the conductive polymer. Further, by adopting electrolytic polymerization in which polymerization proceeds by utilizing a potential difference existing in the battery as a polymerization reaction, there is an advantage that it is not necessary to introduce any additive or any device for the purpose of polymerization.

  The polymerization step is preferably a step of applying a voltage between the positive electrode and the negative electrode in a state where the positive electrode and the negative electrode are in contact with the electrolytic solution. Application of a voltage between the positive and negative electrodes is an operation normally performed as a lithium secondary battery, and simplification of the manufacturing process and manufacturing equipment can be expected.

  The positive electrode preferably includes positive electrode active material particles made of a lithium composite oxide, and the polymerization step is preferably a step of uniformly combining the conductive polymer and the positive electrode active material particles. By containing a particulate positive electrode active material as the positive electrode, it can be uniformly dispersed with the conductive polymer produced by electrolytic polymerization.

  Furthermore, it is desirable that the polymerizable compound contains one or more compounds selected from the group consisting of pyrrole, pyrrole derivatives, thiophene and thiophene derivatives.

  As this polymeric compound, the compound represented by the following general formula (A) or general formula (B) can be included.

(In Formula (A) and Formula (B), R ^{1 to} R ⁵ are each independently selected from hydrogen and an alkyl group having 1 to 4 carbon atoms.)
In particular, in the general formula (A), at least one of R ^{1 to} R ³ is preferably any one of the following formulas (1) to (4).

(Formulas (1) to (4) are bonded to the carbon atom or nitrogen atom of the pyrrole ring in the formula (A) at the portion of *. In formulas (1) to (4), R is H, OH, CH ₃ or NH _{2. In the} formulas (1) to (4), Y is — (CH ₂ ) _m — (m is an integer of 0 to 10), and when m is 1 or more, Y is constituted. One or more of the methylene groups are -O-, -NH-, -S-,

May be substituted. )
Moreover, as said polymeric compound, the compound represented by the following general formula (C) can be included.

(In formula (C), m is an integer of 1 to 10)

  Since the manufacturing method of the lithium secondary battery of this invention has the above structure, the following effects are exhibited. That is, it is possible to produce a conductive polymer by electropolymerizing a polymerizable compound, which is a monomer of the conductive polymer formed on the positive electrode, in the electrolytic solution, and it is easy to form the conductive polymer on the positive electrode. Can be introduced.

  Furthermore, since the electrolytic polymerization can proceed after the lithium secondary battery is actually used, the produced conductive polymer and the surface of the positive electrode can be sufficiently brought into close contact with each other. In other words, by conducting the electrolytic polymerization in a state where the positive electrode is immersed in the electrolytic solution and the polymerizable compound is contained in the electrolytic solution, the conductive polymer can be generated on the surface of the positive electrode with good adhesion. In addition, since it can be used as it is without the need for processing with large deformation after that, the generated conductive polymer can be reliably kept in close contact with the surface of the positive electrode and has high performance. It can be demonstrated and maintained.

  The method for producing a lithium secondary battery of the present invention will be described in detail below based on the embodiment.

  The manufacturing method of the lithium secondary battery of this embodiment is a method of manufacturing a lithium secondary battery provided with a positive electrode, a negative electrode, and an electrolytic solution, and includes a monomer addition step and a polymerization step. The manufacturing method of the lithium secondary battery according to the present embodiment includes, as other steps, a positive electrode, a negative electrode, an electrolytic solution preparation step, a combination step thereof, and other necessary steps.

(Monomer addition process)
A monomer addition process is a process of adding a monomer in electrolyte solution. It is sufficient if the monomer addition step is completed before the polymerization step is completed. For example, the monomer is added together when preparing the electrolytic solution, the monomer is added separately after the battery is assembled, and the monomer is added while performing the polymerization process. The added monomer is generally consumed from the electrolytic solution through the polymerization step.

  The monomer to be added is a monomer constituting the conductive polymer finally produced, and is a polymerizable compound that can be electropolymerized. Examples of the polymerizable compound include one or more compounds selected from the group consisting of pyrrole, pyrrole derivatives, thiophene, and thiophene derivatives.

In particular, the polymerizable compound preferably includes a compound represented by the general formula (A). The compound represented by the general formula (A) is pyrrole and its derivatives. As the alkyl group that can be employed as R ^{1 to} R ⁵ , a methyl group is particularly desirable.

Furthermore, it is desirable that at least one of R ^{1 to} R ³ in the general formula (A) is any one of the above formulas (1) to (4). Since these groups have radicals that can contribute to the battery reaction, they contribute to an improvement in battery capacity and a decrease in internal resistance. Therefore, it is desirable that all the polymerizable compounds have these groups of the formulas (1) to (4).

  The polymerizable compound is particularly preferably a compound represented by the general formula (C). Here, the value of m in the general formula (C) and the formulas (1) to (4) is preferably about 1 to 3.

In particular, it is desirable to employ pyrrole in which R ^{1 to} R ³ are hydrogen or the following compound e in which m is 3 among the compounds represented by the general formula (C).

  The amount of the polymerizable compound added is preferably about 0.01 mol / L to 1.0 mol / L in the electrolytic solution, considering the ease of progress of electrolytic polymerization.

  The conditions for the electropolymerization can be determined within a range that can proceed in an atmosphere that can be realized in the manufactured lithium secondary battery. Therefore, as the polymerizable compound, it is desirable to employ a compound that can be electrolytically polymerized in the range of 3.0 V to 4.5 V, which is a general potential state in a lithium secondary battery.

(Polymerization process)
The polymerization step is a step of polymerizing the polymerizable compound at the positive electrode by applying a potential in a state where the positive electrode is in contact with the electrolytic solution. Desirably, the production equipment can be simplified by performing electrolytic polymerization by adopting a state in which the positive electrode, the negative electrode, and the electrolytic solution are assembled in the battery case.

  In particular, when electrolytic polymerization is performed in a state assembled in a battery case, it is possible to apply a voltage between the positive and negative electrodes using positive and negative electrodes in a lithium secondary, and the manufacturing equipment can be further simplified. In this case, it is desirable to use the positive electrode, the negative electrode, and the electrolytic solution after the polymerization step as they are for the completed lithium secondary battery.

  The polymerization step is desirably performed until almost all of the polymerizable compounds contained in the electrolytic solution are reacted, and more preferably, all of the polymerizable compounds are reacted. Accurate judgment as to whether or not the reaction has been completed can be judged from the relationship between voltage and current applied in the polymerization step. For example, when the battery is charged with a constant current, it can be considered that the polymerization is completed when the terminal voltage of the battery continuously exceeds the potential at which electrolytic polymerization proceeds.

(Lithium secondary battery)
The constituent elements of the lithium secondary battery to which the present manufacturing method can be applied and the manufacturing method of the lithium secondary battery will be described in detail below.

  A lithium secondary battery to which the present manufacturing method can be applied includes a positive electrode capable of releasing or storing lithium ions, a negative electrode capable of storing or releasing lithium ions, and an electrolyte that moves lithium ions between the positive electrode and the negative electrode. If there is enough.

  Although it does not specifically limit as a positive electrode, The thing by which the active material layer containing a positive electrode active material was formed in the surface of collectors, such as aluminum foil, can be illustrated. The active material layer is formed by mixing a positive electrode active material, a binder, a conductive additive and the like in a solvent such as water and NMP, and then applying the mixture on a current collector.

  An example of the positive electrode active material is a lithium composite oxide. As the positive electrode active material, it is preferable to adopt a particulate form because it can be more uniformly dispersed with the conductive polymer generated by polymerization.

Does not _{LiNiO 2, LiMnO 2, LiMn 2} O 4, LiCoO 2, LiFeO 2, LiFePO 4 but may be exemplified as being limited thereto as lithium composite oxide. Moreover, the lithium composite oxide can be used not only alone but also in combination of a plurality of these.

  Among them, the lithium composite oxide is preferably at least one of lithium manganese-containing composite oxide, lithium nickel-containing composite oxide, and lithium cobalt-containing composite oxide.

  Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, EPDM, SBR, NBR, and fluororubber. Examples of the conductive assistant include carbon powder such as carbon black and acetylene black. According to this production method, since the conductive polymer can be formed on the positive electrode, the addition amount of the conductive auxiliary agent can be minimized (for example, to the extent that the first voltage application in the polymerization step can be achieved).

  Although it does not specifically limit as a negative electrode, what formed the active material layer containing a negative electrode active material on the surface of collectors, such as copper foil, and what shape | molded negative electrode active materials, such as metallic lithium and a lithium alloy, are illustrated it can. The active material layer is formed by mixing a negative electrode active material, a binder or the like in a solvent such as water or NMP, and then applying the mixture on a current collector.

  The negative electrode active material is a compound that can occlude and release lithium ions. Examples of compounds include metal materials such as lithium, alloy materials containing silicon, tin, etc., graphite, coke, organic polymer compound fired bodies or carbon materials such as amorphous carbon, but are not limited thereto. is not. These compounds can be used not only alone but also in a mixture of a plurality of types, among which graphite is preferable.

  Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, EPDM, SBR, NBR, and fluororubber.

  The electrolytic solution is obtained by dissolving a supporting electrolyte in an organic solvent.

  Examples of the organic solvent include propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and the like. Absent. These organic solvents can be used alone or in combination. Among them, an electrolytic solution containing a carbonate solvent is preferable because of its high stability at high temperatures.

As the supporting electrolyte, LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂₎ ) And the like, but is not limited thereto. These supporting electrolytes can be used not only independently, but also in combination of a plurality of types.

  Moreover, as a lithium secondary battery to which this manufacturing method can be applied, in addition to the above-described constituent elements, known constituent elements such as a separator that electrically insulates between the positive and negative electrodes and a battery case can be applied. Needless to say.

  A lithium secondary battery 100 having the configuration shown in FIG. 1 was manufactured.

(Preparation of positive electrode)
87 parts by mass of LiNiO ₂ as positive electrode active material particles, 10 parts by mass of acetylene black as a conductive additive, 1 part by mass of carboxymethyl cellulose (CMC) as a binder, and polyethylene oxide as a binder 1 part by mass of (PEO) and 1 part by mass of polytetrafluoroethylene (PTFE) as a binder were mixed and dispersed in water to prepare a homogeneous coating liquid.

  The coating liquid was applied to both surfaces of the positive electrode current collector 11 made of aluminum, dried and pressed to form a positive electrode mixture layer, and then cut into a predetermined size to produce a positive electrode.

(Preparation of negative electrode)
98 parts by mass of graphite powder as the negative electrode active material, 1 part by mass of CMC as the binder, and 1 part by mass of styrene butadiene rubber (SBR) as the binder were mixed and dispersed in water to obtain a homogeneous A coating liquid was prepared.

  This coating liquid was applied to both surfaces of the copper negative electrode current collector 21, dried and pressed to form a negative electrode mixture layer, and then cut into a predetermined size to produce a negative electrode.

(Preparation of electrolyte)
Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 7, and LiPF ₆ as a supporting electrolyte was dissolved in the mixed organic solvent at a concentration of 1 mol / L. At the same time, pyrrole (manufactured by Wako Pure Chemical Industries, Ltd.), which is a conductive polymer monomer having electrolytic polymerizability, was dissolved at a concentration of 0.1 mol / L (monomer addition step) to obtain an electrolytic solution.

(Production of battery)
The positive electrode 1 and the negative electrode 2 obtained above were wound in a state where a film 4 made of microporous polyethylene having a thickness of 25 μm as a separator was interposed therebetween to form a wound electrode body. The obtained wound electrode body was inserted into the case 7 and held in the case 7. At this time, one end of the current collecting leads 13 and 23 is welded to the lead tab welded portion of the sheet-like positive electrode 1 and the sheet-like negative electrode 2, and the other ends of the current collecting leads 13 and 23 are respectively connected to the positive electrode terminal portion 5 and the negative electrode terminal of the case. Bonded to part 6.

  Then, after inject | pouring the said electrolyte solution 3 containing a polymeric compound in the case 7 holding the winding type electrode body, the case 7 was sealed and sealed. Through the above procedure, a cylindrical secondary battery having a diameter of 18 mm and an axial length of 65 mm was manufactured and used as a test battery of this example.

(Evaluation of capacity characteristics)
Evaluation of the capacity | capacitance characteristic of the produced lithium secondary battery measured the discharge capacity at the time of discharging to 3.0V with the electric current value equivalent to 1C, after charging to 4.1V with the electric current value equivalent to 1C. The discharge capacity value is the same as that of this example except for the use of an electrolytic solution prepared in the same composition ratio as in this example, except that it does not contain a monomer of a conductive polymer having electrolytic polymerizability. The discharge capacity of a battery (Comparative Example 1) produced using the above was converted to 100. The evaluation results are shown in Table 1.

  In the same manner as in Example 1, except that an electrolytic solution prepared by dissolving pyrrole (manufactured by Wako Pure Chemical Industries, Ltd.) at a concentration of 0.2 mol / L was used as a conductive polymer monomer having electrolytic polymerization properties. A battery was prepared and the discharge capacity was measured. The evaluation results are shown in Table 1.

  The same method as in Example 1 except that an electrolytic solution prepared by dissolving the above-mentioned compound e at a concentration of 0.01 mol / L was used as a polymerizable compound that is a monomer of a conductive polymer having electrolytic polymerization properties. A battery was prepared and the discharge capacity was measured. The evaluation results are shown in Table 1.

  Compound e was synthesized by the method shown below.

  Step 1: Compound b (3-amino-1-propanol: 18 mL, 0.24 mol) was added to acetic acid 33 mL while cooling with an ice bath, and then compound a (2,5-dimethoxytetrahydrofuran: 9 mL, 0. 07 mol) was added all at once, and then refluxed for 2 hours.

After cooling to room temperature, 120 mL of water was added, and extraction operation was performed 3 times with 50 mL of dichloromethane. The obtained organic layer was dried over Na ₂ SO ₄ and the solvent was removed under reduced pressure. Methanol (60 mL) and 20% by mass NaOH aqueous solution (60 mL) were added to the residue, and the mixture was stirred at room temperature for 2.5 hours.

Then, 100 mL of saturated NaCl aqueous solution was added, and extraction operation was performed 3 times with 50 mL of dichloromethane. The obtained organic layer was dried over Na ₂ SO ₄ , the solvent was removed under reduced pressure, and the residue was purified by column chromatography (developing solvent: ethyl acetate-hexane 1: 1) to obtain compound f (1- (3-hydroxypropyl). ) -1H-pyrrole). The yield was 4.77 g, and the yield was 54%.

  Step 2: Compound c (3.5 g, 0.28 mol) and triethylamine (4.16 mL, 0.30 mol) were added to 25 mL of dichloromethane while cooling with an ice bath in a nitrogen atmosphere, and then methanesulfonic acid. Chloride (2.45 mL, 0.30 mol) was added dropwise and stirred at room temperature for 3 hours. 60 mL of water was added, and extraction operation was performed with 60 mL of dichloromethane.

The obtained organic layer was washed with 60 mL of 5% by mass NaHCO ₃ aqueous solution and then dried over Na ₂ SO ₄ , and the solvent was removed under reduced pressure. Then, it refine | purified by column chromatography (developing solvent: chloroform), and compound d (1- (3'-MsO-propyl) -1H-pyrrole) was obtained. The yield was 5.45 g, and the yield was 96%.

  Step 3: Under a nitrogen atmosphere, NaH (60% in Oil, 0.81 g, 0.203 mol) and 4-hydroxy-TEMPO (3.5 g, 0.203 mol) washed with hexane were added to 30 mL of DMF, and 0 ° C. For 1 hour.

Thereafter, compound d (5 g, 0.246 mol) was added dropwise and stirred at room temperature for 15 hours. 60 mL of water was added, and extraction operation was performed with 150 mL of hexane. The obtained organic layer was washed 6 times with 25 mL of water, dried over Na ₂ SO ₄ , and the solvent was removed under reduced pressure. Subsequently, purification was performed by column chromatography (developing solvent: ethyl acetate-hexane 1: 3) to obtain compound e. The yield was 3.28 g, and the yield was 58%.

  A battery was produced in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving Compound e at a concentration of 0.1 mol / L was used as a monomer of a conductive polymer having electrolytic polymerization property. The capacity was measured. The evaluation results are shown in Table 1.

Comparative Example 1

  Table 1 shows the evaluation results of producing a battery and measuring the discharge capacity in the same manner as in Example 1 except that an electrolytic solution containing no electropolymerizable conductive polymer monomer was used.

  As is clear from Table 1, a lithium secondary battery is prepared using an electrolytic solution containing a polymerizable compound having an electrolytic polymerization property, so that it has higher performance than the conventional test battery of Comparative Example 1. It became clear that a battery was obtained.

  It is assumed that the polymerizable compound in the electrolytic solution was improved in performance because it was electrolytically polymerized at the positive electrode due to the potential difference generated by charging, and the lithium composite oxide on the positive electrode could be uniformly coated. Is done.

  As described above, this manufacturing method produces a battery with excellent capacity characteristics by a cheaper and simpler process than before, in which only the first charge is performed in a state where a polymerizable compound is contained in the electrolytic solution. It was confirmed that it was possible.

  The concentration of pyrrole added was 0.2 mol / L because the battery capacity of Example 1 with 0.1 mol / L added to the electrolyte was 113 and the battery capacity of Example 2 with 0.2 mol / L added was not significantly different from 112. It was suggested that a sufficient effect can be obtained by adding up to about L and further up to about 0.1 mol / L.

  The battery capacity of Example 3 in which 0.01 mol / L of compound e was added to the electrolytic solution was 116, which was higher than those in Examples 1 and 2 in which pyrrole was added. This is thought to be due to the fact that the radical of compound e contributes to the battery reaction, resulting in an increase in battery capacity.

  The addition concentration of compound e is not much different from the battery capacity of Example 3 in which 0.01 mol / L was added with respect to the electrolyte solution and 116 in Example 4 to which 0.1 mol / L was added. It has been found that it increases with increase, and it is desirable to add to about 0.1 mol / L or more.

It is the figure which showed the structure of the cylindrical lithium secondary battery produced in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Lithium secondary battery 1 ... Positive electrode 11 ... Positive electrode collector 12 ... Positive electrode compound material layer 13 ... Current collector lead 2 ... Negative electrode 21 ... Negative electrode collector material 22 ... Negative electrode compound material layer 23 ... Current collector lead 3 ... Electrolyte solution 4 ... Separator 5 ... Positive electrode terminal part 6 ... Negative electrode terminal part 7 ... Case

Claims (9)

A method for producing a lithium secondary battery, comprising: a positive electrode capable of releasing or storing lithium ions; a negative electrode capable of storing or releasing lithium ions; and an electrolyte that moves the lithium ions between the positive electrode and the negative electrode.
A monomer addition step of containing a polymerizable compound that is a monomer of a conductive polymer having electrolytic polymerization in the electrolytic solution;
A polymerization step of polymerizing the polymerizable compound at the positive electrode by applying a potential in a state where the positive electrode is in contact with the electrolytic solution;
A method for producing a lithium secondary battery, comprising:   The method for producing a lithium secondary battery according to claim 1, wherein the polymerization step is a step of applying a voltage between the positive electrode and the negative electrode in a state where the positive electrode and the negative electrode are in contact with the electrolytic solution. The positive electrode contains positive electrode active material particles made of a lithium composite oxide,
The method for producing a lithium secondary battery according to claim 1, wherein the polymerization step is a step of uniformly combining the conductive polymer and the positive electrode active material particles.   The method for producing a lithium secondary battery according to claim 1, wherein the polymerizable compound includes one or more compounds selected from the group consisting of pyrrole, pyrrole derivatives, thiophene, and thiophene derivatives. The manufacturing method of the lithium secondary battery in any one of Claims 1-4 in which the said polymeric compound contains the compound represented by the following general formula (A) or general formula (B).

(In Formula (A) and Formula (B), R ^{1 to} R ⁵ are each independently selected from hydrogen and an alkyl group having 1 to 4 carbon atoms.) The method for producing a lithium secondary battery according to claim 5, wherein in the general formula (A), at least one of R ^{1 to} R ³ is any one of the following formulas (1) to (4).

(Formulas (1) to (4) are bonded to the carbon atom or nitrogen atom of the pyrrole ring in the formula (A) at the portion of *. In formulas (1) to (4), R is H, OH, CH ₃ or NH _{2. In the} formulas (1) to (4), Y is — (CH ₂ ) _m — (m is an integer of 0 to 10), and when m is 1 or more, Y is constituted. One or more of the methylene groups are -O-, -NH-, -S-,

May be substituted. ) The method for producing a lithium secondary battery according to claim 6, wherein the polymerizable compound contains a compound represented by the following general formula (C).

(In formula (C), m is an integer of 1 to 10)   The method for producing a lithium secondary battery according to claim 1, wherein the concentration of the polymerizable compound in the electrolytic solution is 0.01 to 1.0 mol / L.   The method for producing a lithium secondary battery according to claim 1, wherein the polymerizable compound is capable of electrolytic polymerization in a range of 3.0V to 4.5V.

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