BINDER SUITABLE FOR ELECTRICITY STORAGE DEVICE ELECTRODES, BINDER SOLUTION FOR ELECTRICITY STORAGE DEVICE ELECTRODES, ELECTRICITY STORAGE DEVICE ELECTRODE SLURRY, ELECTRICITY STORAGE DEVICE ELECTRODE, AND ELECTRICITY STORAGE DEVICE

Abstract

The present disclosure provides a binder for electricity storage device electrodes, said binder containing a polyvinyl alcohol resin and an electrolyte solution-swellable resin.

Claims

1: A binder, comprising: a polyvinyl alcohol resin; and an electrolyte solution-swellable resin having an electrolyte solution swelling rate, which is represented by the following equation (1), of 10% by mass or more:
Electrolyte solution swelling rate=((W.sub.2−W.sub.1)/W.sub.1×100)  (1) [wherein, W.sub.1 represents the mass (g) of the resin prior to immersion in an electrolyte solution; and W.sub.2 represents the mass (g) of the resin after 24-hour immersion in diethyl carbonate at 25° C.], wherein the polyvinyl alcohol resin in the state of an aqueous solution having a solid content concentration of 10% by mass has a viscosity of 4 Pa.Math.s or higher at 25° C. and a shear rate of 10 s.sup.−1.

2: The binder according to claim 1, wherein the polyvinyl alcohol resin in the state of an aqueous solution having a solid content concentration of 10% by mass has a viscosity of 4 Pa.Math.s to 30 Pa.Math.s at 25° C. and a shear rate of 10 s.sup.−1, and the aqueous solution at 25° C. has a thixotropic index, which is defined as a viscosity ratio between the viscosity at a shear rate of 10 s.sup.−1 and the viscosity at a shear rate of 100 s.sup.−1, of 1.8 to 5.

3: The binder according to claim 1, wherein the polyvinyl alcohol resin in the state of an N-methyl-2-pyrrolidone solution having a solid content concentration of 7.5% by mass has a viscosity of 4 Pa.Math.s to 35 Pa.Math.s at 25° C. and a shear rate of 10 s.sup.−1, and the solution at 25° C. has a thixotropic index, which is defined as a viscosity ratio between the viscosity at a shear rate of 10 s.sup.−1 and the viscosity at a shear rate of 100 s.sup.−1, of 2 to 6.

4: The binder according to claim 1, wherein the polyvinyl alcohol resin is a vinyl alcohol-based polymer having a crosslinked structure.

5: The binder according to claim 1, wherein the polyvinyl alcohol resin has a modification rate of 0.02% by mole to 5% by mole based on the number of moles of all monomer units constituting the polyvinyl alcohol resin.

6: The binder according to claim 1, wherein the electrolyte solution-swellable resin has an electrolyte solution elution rate, which is represented by the following equation (2), of 5% by mass or less:
Electrolyte solution elution rate=((W.sub.1−W.sub.3)/W.sub.1×100)  (2) [wherein, W.sub.1 represents the mass (g) of the resin prior to immersion in an electrolyte solution; and W.sub.3 represents the mass (g) of the resin after 24-hour immersion in diethyl carbonate at 25° C. and subsequent 3-hour drying in a hot air dryer at 80° C.].

7: An electricity storage device electrode, comprising the binder according to claim 1.

8: A binder solution for an electricity storage device electrode, comprising: the binder according to claim 1; and a solvent.

9: An electricity storage device electrode slurry, comprising: the binder solution for an electricity storage device electrode according to claim 8; and an active material.

10: The electricity storage device electrode slurry according to claim 9, wherein the content of the binder for an electricity storage device electrode is 0.1 parts by mass to 20 parts by mass with respect to 100 parts by mass of the active material.

11: An electricity storage device electrode, comprising: a cured product of the electricity storage device electrode slurry according to claim 9; and a current collector.

12: An electricity storage device, comprising the electricity storage device electrode according to claim 11.

Description

EXAMPLES

[0112] Examples of the present invention will now be described; however, the present invention is not limited thereto. In the below-described Examples, “%” pertains to mass unless otherwise specified. First, measurement methods and evaluation methods will be described. It is noted here that the physical property values (or evaluation values) described herein are based on the values obtained by the following respective methods.

[0113] Measurement of the physical property values of each PVA used in the below-described Examples and Comparative Examples, evaluation of binder aqueous solutions and NMP solutions containing each PVA, evaluation in electrode application, and evaluation in battery application were performed in accordance with the following methods.

<Modification Rate of PVA>

[0114] The modification rate of each PVA used in the below-described Examples and Comparative Examples (content ratio of a unit derived from a monomer (a) based on the number of moles of all monomer units of each PVA) was determined by a method using .sup.1H-NMR with a vinyl ester-based polymer that is a precursor of each PVA.

<Saponification Degree of PVA>

[0115] The saponification degree of each PVA used in the below-described Examples and Comparative Examples was determined in accordance with JIS-K6726:1994.

<Polymerization Degree of PVA>

[0116] The polymerization degree (viscosity-average polymerization degree) of each PVA used in the below-described Examples and Comparative Examples was determined by the method prescribed in JIS-K6726:1994.

[0117] For example, when monomethyl maleate is used as the monomer (a), the above-described content ratio can be determined by the following procedure. That is, a vinyl ester-based polymer, which is a precursor of each PVA, is thoroughly purified by reprecipitation at least three times using n-hexane/acetone as a solvent, and the resulting purified product is dried under reduced pressure at 50° C. for 2 days to prepare a sample for analysis. This sample is dissolved in CDCl.sub.3 and measured at room temperature using 1H-NMR. From a peak α (4.7 to 5.2 ppm) derived from the methine structure of the vinyl ester unit contained in the vinyl ester-based polymer and a peak β (3.6 to 3.8 ppm) derived from the methyl group of the methyl ester moiety contained in a unit derived from the monomer (a), the content ratio S of the unit derived from the monomer (a) can be calculated using the following equation:

S(% by mole)={(Number of protons of β/3)/(Number of protons of α+(Number of protons of β/3))}×100

<Viscosity Measurement and TI Calculation for Binder Aqueous Solution and NMP Solution>

[0118] Using either of a binder aqueous solution having a solid content concentration of 10% by mass and a binder NMP solution having a solid content concentration of 7.5% by mass, which were prepared in each of the below-described Examples and the Comparative Examples, as a measurement sample, the viscosity at 25° C. was measured at shear rates of 10 s.sup.−1 and 100 s.sup.−1 using an E-type viscometer (manufactured by Brookfield Engineering Laboratories, Inc.). Further, from the thus measured values, the TI, which is defined as a viscosity ratio at 25° C. between the viscosity at a shear rate of 10 s.sup.−1 and the viscosity at a shear rate of 100 s.sup.−1, was calculated.

<Measurement of Peel Strength (N/m) of Lithium Ion Secondary Battery in Positive Electrode Application>

[0119] For each of the lithium ion secondary battery electrodes (positive electrodes) produced in the below-described Examples and Comparative Examples, the strength in peeling of a cured product (a portion derived from the slurry prepared in each of Examples and Comparative Examples) from an aluminum foil (positive electrode) used as a current collector was measured. Specifically, the slurry-coated surface of each lithium ion secondary battery electrode that was produced and a stainless steel plate were pasted together using double-sided adhesive tape (manufactured by Nichiban Co., Ltd.), and the 180° peel strength (peeling width: 10 mm, peeling speed: 100 mm/min) was measured using a 50-N load cell (manufactured by IMADA Co., Ltd.).

<Measurement of Initial Charge-Discharge Efficiency and Direct-Current Resistance of Lithium Ion Secondary Battery in Positive Electrode Application>

[0120] For each of the coin batteries produced in the below-described Examples and Comparative Examples, a test was conducted using a commercially available charge-discharge tester (TOSCAT3100, manufactured by Toyo System Co., Ltd.). The resistance value measured when a current of 0.1 mA was applied for 3 seconds after initial charging was defined as the direct-current resistance. As for charging, the coin battery was charged at a constant current of 0.2 C (about 1 mA/cm.sup.2) up to 4.2 V in terms of lithium potential. As for discharging, the coin battery was discharged at a constant current of 0.2 C (about 0.5 mA/cm.sup.2) down to 3 V in terms of lithium potential. The coin battery was placed in a 25° C. thermostat chamber and subjected to initial charging and discharging under the above-described conditions, and the charge capacity, the discharge capacity, and the direct-current resistance were measured. The initial charge-discharge efficiency (%) was calculated using the following equation: (Discharge capacity)/(Charge capacity)×100.

<Measurement of Discharge Capacity Retention Rate (%) of Lithium Ion Secondary Battery in Positive Electrode Application>

[0121] For each of the coin batteries produced in the below-described Examples and Comparative Examples, a rate test was conducted using a commercially available charge-discharge tester (TOSCAT3100, manufactured by Toyo System Co., Ltd.). As for charging, the coin battery was charged at a constant current of 0.2 C (about 1 mA/cm.sup.2) up to 4.2 V in terms of lithium potential. As for discharging, the coin battery was discharged at a constant current of 0.2 C (about 0.5 mA/cm.sup.2) down to 3 V in terms of lithium potential. The coin battery was placed in a 25° C. thermostat chamber and subjected to three cycles of initial charging and discharging under the above-described conditions, after which the coin battery was subjected to one cycle of charging and discharging with the discharge rate being changed to 5 C. The ratio of the discharge capacity at 5 C with respect to the discharge capacity at 0.2 C in this process was defined as the discharge capacity retention rate (%).

<Evaluation of Occurrence of Breakage of Lithium Ion Secondary Battery Electrodes in Positive Electrode Application>

[0122] From each of the lithium ion secondary battery electrodes (positive electrodes) produced in the below-described Examples and Comparative Examples, 10 pieces were punched out using a D14-mm punching machine, and the number of the electrode pieces in which the active material was detached from the current collector was measured.

(Production of PVAs)

[PVA-1]

[0123] To a reactor equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a comonomer drip port, and a polymerization initiator addition port, 920 parts by mass of vinyl acetate and 80 parts by mass of methanol were added, and the system was purged with nitrogen for 30 minutes under nitrogen bubbling. Itaconic anhydride was selected as the monomer (a), and a methanol solution thereof (concentration: 20%) was purged with nitrogen by nitrogen bubbling. Heating of the reactor was initiated and, once the internal temperature reached 60° C., polymerization was initiated with an addition of 0.25 parts by mass of 2,2′-azobisisobutyronitrile (AIBN). To this reactor, the above-described methanol solution of itaconic anhydride was added dropwise, and polymerization was carried out at 60° C. for 3 hours while maintaining the monomer composition ratio constant in the polymerization solution, after which the polymerization was terminated by cooling. The total amount of the monomer (a) added until the termination of polymerization was 0.7 parts by mass, and the solid content concentration at the termination of polymerization was 33.3%. Subsequently, unreacted monomers were removed while occasionally adding methanol at 30° C. under reduced pressure, whereby a methanol solution of a vinyl ester-based polymer (concentration: 35%) was obtained. Next, methanol was further added to this methanol solution to prepare another methanol solution of the vinyl ester-based polymer and, to 790.8 parts by mass of the thus prepared methanol solution (containing 200.0 parts by mass of the polymer), 9.2 parts by mass of a 10% methanol solution of sodium hydroxide was added to perform saponification at 40° C. The polymer concentration of the resulting saponification solution was 25%, and the molar ratio of sodium hydroxide with respect to the vinyl acetate unit in the polymer was 0.007. Since a gel-like matter was generated in about 15 minutes after the addition of the methanol solution of sodium hydroxide, the gel-like matter was pulverized using a pulverizer, and the saponification solution was left to stand at 40° C. for 1 hour to allow saponification to proceed. Thereafter, 500 parts by mass of methyl acetate was added to neutralize the remaining alkali. After confirming that the neutralization was completed using a phenolphthalein indicator, the resulting solution was filtered to obtain a white solid. To this white solid, 2,000 parts by mass of methanol was added, and the resultant was left to stand at room temperature for 3 hours, followed by washing. This washing operation was repeated three times, and a white solid obtained by subsequent centrifugal dehydration was heat-treated at 120° C. for 4.5 hours in a dryer, whereby PVA-1 was obtained. The materials used for the production of PVA-1 as well as the physical properties and the like of PVA-1 are summarized in Table 1 below.

[PVA-2 to PVA-6]

[0124] Various PVAs were produced in the same manner as in the production of PVA-1, except that the polymerization conditions such as the added amounts of vinyl acetate and methanol, the type and the amount of the monomer (a) used in the polymerization, and the polymerization rate (reaction rate (%) of monomers (vinyl acetate and monomer (a)) at the termination of polymerization, which is calculated by: 100× (mass of vinyl ester-based polymer at the termination of polymerization)/(amount of added monomers)), as well as the saponification conditions such as the molar ratio of sodium hydroxide were changed as shown in Table 1 below. The physical properties of the thus obtained PVAs are summarized in Table 1 below.

TABLE-US-00001 TABLE 1 Vinyl acetate Methanol Type of Added amount Polymerization NaOH molar Type (parts (parts monomer of monomer (a) rate ratio in of PVA by mass) by mass) (a) (parts by mass) (%) saponification PVA-1 920 80 itaconic 0.7 25 0.007 anhydride PVA-2 920 80 monomethyl 0.6 25 0.01 maleate PVA-3 600 400 dimethyl 7.0 60 0.01 maleate PVA-4 920 80 monomethyl 4.9 25 0.007 fumarate PVA-5 920 80 vinyltrimethoxysilane 2.9 25 0.014 PVA-6 920 80 monomethyl 26.3 25 0.007 maleate

(Production of Polyvinyl Acetal Resins)

[Polyvinyl Acetal Resin-1]

[0125] To a three-necked flask equipped with a reflux condenser and a thermometer, 150 g of acetone, 100 g of water, and 10 g of 1-butanal were added and, while stirring these materials with a magnetic stirrer, 50 g of a polyvinyl alcohol (saponification degree: 99% by mole, average polymerization degree: 1,700) was added over a period of 1 minute. A mixed solution of 50 g of water and 21.2 g of 47%-by-mass sulfuric acid was further added dropwise using a dropping funnel over a period of 5 minutes, and the resultant was heated to 30° C. and allowed to react for 5 hours. After adding a 1-mol/L aqueous sodium hydroxide solution until the pH reached 8, the resulting solid was recovered by filtration. The thus recovered solid was washed five times with a mixed solvent of acetone and water (mass ratio=1:1), and subsequently dried for 6 hours at 120° C. under a pressure of 0.005 MPa, whereby a polyvinyl acetal resin having a hydroxyl equivalent of 74 was obtained. The polymer used in the below-described binder solution is summarized in Table 2 below.

[Polyvinyl Acetal Resin-2]

[0126] A polyvinyl acetal resin-2 was produced in the same manner as the production method of [Polyvinyl Acetal Resin-1], except that 1-nonanal was used in place of 1-butanal and the polyvinyl alcohol (saponification degree: 99% by mole, average polymerization degree: 1,700) was changed to a polyvinyl alcohol (saponification degree: 99% by mole, average polymerization degree: 2,400). The polymer used in the below-described binder solution is summarized in Table 2 below.

[0127] The following Examples and Comparative Examples represent the use of the above-produced PVA-1 to PVA-6 for the formation of a positive electrode.

Preparation of Aqueous PVA Solution

[0128] PVA-1 was used as a PVA that is a constituent of a binder. First, the modification rate, the saponification degree, and the polymerization degree of PVA-1 were determined by the above-descried methods. Next, water was added to PVA-1, and the resultant was mixed with heating at 80° C. for 1 hour to obtain an aqueous PVA solution which contained a vinyl alcohol-based polymer and had a solid content concentration of about 10% by mass. The solid content concentration was calculated from the mass of remaining solid after weighing 3 g of the aqueous PVA solution in an aluminum cup and drying it in a hot air dryer at 105° C. for 3 hours. For the aqueous PVA solution, the viscosity was measured and the TI was calculated by the above-described respective methods. The physical properties (modification rate, saponification degree, and polymerization degree) of the PVA and the physical properties (viscosity and TI) of the aqueous PVA solution are summarized in Table 3 below.

Example 1

Preparation of NMP Solution of PVA

[0129] In Example 1, PVA-1 was used as a PVA (hereinafter, also referred to as “resin a”) that is a constituent of a binder. NMP (manufactured by FUJIFILM Wako Pure Chemical Corporation) in an amount of 92.5 parts by mass was added to 7.5 parts by mass of PVA-1, and these materials were heated to 80° C. with stirring, and then further heated with stirring until complete dissolution was visually confirmed, whereby an NMP solution of PVA, which contained a vinyl alcohol-based polymer and had a solid content concentration of about 7.5% by mass, was obtained. The solid content concentration was calculated from the mass of remaining solid after weighing 3 g of the solution of PVA in an aluminum cup and drying it in a hot air dryer at 120° C. for 4 hours. For the NMP solution of PVA, the viscosity was measured and the TI was calculated by the above-described respective methods. Further, for the NMP solution of PVA, the NMP solubility was evaluated by the above-described method. The physical properties (modification rate, saponification degree, and polymerization degree) of the PVA and the physical properties (viscosity and TI) of the NMP solution of PVA are summarized in Table 3 below.

Preparation of Binder Solution

[0130] A binder solution was prepared by mixing the above-obtained NMP solution of PVA and an NMP solution of KYNAR (registered trademark) HSV900 (PVdF, manufactured by Arkema K. K.) used as an electrolyte solution-swellable resin such that the ratio of the PVA and the electrolyte solution-swellable resin (PVA:electrolyte solution-swellable resin) was 1:9. A non-PVA resin containing an electrolyte solution-swellable resin is hereinafter also referred to as “resin b”.

Preparation of Positive Electrode Slurry

[0131] Further, a positive electrode slurry was prepared by adding the above-obtained binder solution, NCM (“CELLSEED C-5H”, manufactured by Nippon Chemical Industrial CO., Ltd.) as a positive electrode active material, and Super-P (manufactured by TIMCAL Ltd.) as a conductive aid (conductivity-imparting agent) to a dedicated container and kneading these materials using a planetary stirrer (ARE-250, manufactured by THINKY Corporation). In this addition, the solid content in the binder solution was 3 parts by mass, the solid content of NCM was 95 parts by mass, and the solid content of Super-P was 2 parts by mass. In other words, the composition ratio of the active material, the conductive aid, and the binder in the positive electrode slurry (NCM powder:conductive aid:binder) was 95:2:3 (mass ratio) in terms of solid content.

Production of Positive Electrode for Lithium Ion Secondary Battery

[0132] The positive electrode slurry obtained in the above-described manner was applied onto a current collector formed of an aluminum foil (CST8G, manufactured by Fukuda metal Foil & Powder Co., Ltd.) using a bar coater (T101, manufactured by Matsuo Sangyo Co., Ltd.). This current collector was subjected to 30-minute primary drying at 80° C. in a hot air dryer and then a rolling process using a roll press (manufactured by Hohsen Corp.). Subsequently, the thus rolled current collector was punched out as a battery electrode (φ14 mm), which was then subjected to 3-hour secondary drying at 140° C. under reduced pressure to produce a coin battery positive electrode. A total of ten φ14 mm punched-out electrodes were produced, and the number of broken electrodes was counted. Further, an unbroken electrode was selected as the electrode to be used in a coin battery. For the thus obtained coin battery positive electrode, the peel strength was measured by the above-described method. The results thereof are summarized in Table 4 below.

Production of Lithium Ion Secondary Battery

[0133] The battery positive electrode obtained in the above-described manner was transferred to a glove box (manufactured by Miwa Manufacturing Co., Ltd.) in an argon gas atmosphere. A lithium metal foil (0.2 mm in thickness, φ16 mm) and a polypropylene film (CELGARD #2400, manufactured by Polypore International, Inc.) were used as a negative electrode and a separator, respectively, and a mixed solvent system (1M-LiPF.sub.6, EC/EMC=3/7% by volume, VC: 2% by mass) obtained by adding vinylene carbonate (VC) to ethylene carbonate (EC) and ethyl methyl carbonate (EMC) for lithium hexafluorophosphate (LiPF.sub.6) was injected as an electrolyte solution. A coin battery (2032-type) was produced according to this configuration. For the thus obtained coin battery, the initial charge-discharge efficiency, the 5C discharge capacity retention rate, and the direct-current resistance were measured by the above-described respective methods. The results thereof are summarized in Table 4 below.

Examples 2 to 22

[0134] A binder solution and a positive electrode slurry were prepared and a positive electrode for lithium ion secondary battery and a lithium ion secondary battery were produced in the same manner as in Example 1, except that the resin a and the resin b were each selected from the resins shown in Table 2 and the ratio of the resin a and the resin b (resin a:resin b) was changed as shown in Table 4, and the same measurements and evaluations were performed. The results thereof are summarized in Tables 3 and 4 below.

Comparative Examples 1 to 17

[0135] A binder solution and a positive electrode slurry were prepared and a positive electrode for lithium ion secondary battery and a lithium ion secondary battery were produced in the same manner as in Example 1, except that the resin a and the resin b were each selected from the resins shown in Table 2 and the ratio of the resin a and the resin b (resin a:resin b) was changed as shown in Table 4, and the same measurements and evaluations were performed. The results thereof are summarized in Tables 3 and 4 below.

TABLE-US-00002 TABLE 2 Swelling rate Elution rate Resin Type [% by mass] [% by mass] Resin 1 PVA-1 <1 <1 Resin 2 PVA-2 <1 <1 Resin 3 PVA-3 <1 <1 Resin 4 PVA-4 <1 <1 Resin 5 PVA-5 <1 <1 Resin 6 PVA217 (manufactured by <1 <1 Kuraray Co., Ltd.) Resin 7 Polyvinyl acetal resin-1 2 <1 Resin 8 PVDF#1120 (PVDF 6 <1 manufactured by Kureha Corp.) Resin 9 KYNER HSV900 (PVDF 13 <1 manufactured by Arkema K.K.) Resin 10 PVDF-HFP (manufactured by 16 <1 Sigma-Aldrich Co., LLC.) Resin 11 Polyvinyl acetal resin-2 45 2 Resin 12 PVA-6 <1 <1 Resin 13 PVA235 (manufactured by <1 <1 Kuraray Co., Ltd.) *PVA217: saponification degree = 88, polymerization degree = 1,700 *PVA235: saponification degree = 88, polymerization degree = 3,500

TABLE-US-00003 TABLE 3 TI value TI value (viscosity at (viscosity at Viscosity Viscosity 10 s.sup.−1/ Viscosity Viscosity 10 s.sup.−1/ of aqueous of aqueous viscosity at of NMP of NMP viscosity at Modifi- Saponifi- Polymeri- solution at solution at 100 s.sup.−1) solution at solution at 100 s.sup.−1) Type of cation cation zation 10 s.sup.−1 100 s.sup.−1 (aqueous solution 10 s.sup.−1 100 s.sup.−1 (NMP solution PVA rate degree degree [Pa .Math. s] [Pa .Math. s] viscosity) [Pa .Math. s] [Pa .Math. s] viscosity) PVA-1 0.2 80 3,500 14.594 6.985 2.01 15.178 5.588 2.72 PVA-2 0.2 88 3,500 15.633 7.051 2.22 15.507 5.739 2.70 PVA-3 1.1 88 1,000 4.852 2.651 1.83 5.240 2.041 2.57 PVA-4 1.1 80 3,500 22.367 6.540 3.42 23.485 4.905 4.79 PVA-5 0.2 95 3,500 27.388 11.179 2.45 30.127 8.272 3.64 PVA-6 7.6 80 3,500 32.134 7.994 4.02 41.774 5.596 7.47 PVA217 0 88 1,700 0.824 0.545 1.51 0.783 0.474 1.65 PVA235 0 88 3,500 8.362 5.049 1.66 8.028 4.544 1.77

TABLE-US-00004 TABLE 4 Initial 5C discharge Occurrence Resin charge- capacity Direct- of mixing Peel discharge retention current breakage PVA Non-PVA ratio strength efficiency rate resistance [number of (resin a) (resin b) (a:b) [N/m] [%] [%] [Ω] electrodes] Example 1 Resin 1 Resin 9 1:9 431 87 79 680 0 Example 2 Resin 1 Resin 9 5:5 542 86 76 702 0 Example 3 Resin 1 Resin 9 9:1 603 84 74 715 0 Example 4 Resin 1 Resin 10 5:5 504 85 75 643 0 Example 5 Resin 2 Resin 9 5:5 579 86 77 734 0 Example 6 Resin 2 Resin 10 1:9 415 87 78 621 0 Example 7 Resin 2 Resin 10 5:5 537 86 77 654 0 Example 8 Resin 2 Resin 10 9:1 649 85 75 667 0 Example 9 Resin 2 Resin 11 1:9 597 87 77 678 0 Example 10 Resin 2 Resin 11 9:1 559 85 75 706 0 Example 11 Resin 3 Resin 9 5:5 411 86 78 691 0 Example 12 Resin 3 Resin 10 8:2 406 85 75 741 0 Example 13 Resin 4 Resin 9 9:1 672 85 74 739 0 Example 14 Resin 4 Resin 9 5:5 631 86 78 683 0 Example 15 Resin 4 Resin 10 5:5 623 85 77 672 0 Example 16 Resin 4 Resin 11 5:5 615 86 77 689 0 Example 17 Resin 5 Resin 9 5:5 692 86 78 674 0 Example 18 Resin 5 Resin 10 9:1 709 85 75 725 0 Example 19 Resin 5 Resin 10 5:5 664 87 77 701 0 Example 20 Resin 5 Resin 11 9:1 671 85 75 733 0 Example 21 Resin 12 Resin 9 5:5 731 82 65 867 0 Example 22 Resin 13 Resin 9 5:5 523 82 68 827 0 Comparative Resin 1 none 10:0  642 82 62 1,055 0 Example 1 Comparative Resin 2 none 10:0  683 82 61 1,127 0 Example 2 Comparative Resin 3 none 10:0  420 81 60 1,154 0 Example 3 Comparative Resin 4 none 10:0  701 82 61 1,033 0 Example 4 Comparative Resin 5 none 10:0  754 80 62 1,076 0 Example 5 Comparative Resin 6 none 10:0  339 81 59 1,209 1 Example 6 Comparative none Resin 7  0:10 412 84 63 988 0 Example 7 Comparative none Resin 8  0:10 25 84 64 979 4 Example 8 Comparative none Resin 9  0:10 112 91 82 645 2 Example 9 Comparative none Resin 10  0:10 31 88 81 596 3 Example 10 Comparative none Resin 11  0:10 311 88 80 622 1 Example 11 Comparative none Resin 12  0:10 53 72 55 648 3 Example 12 Comparative none Resin 13  0:10 21 74 53 673 4 Example 13 Comparative Resins 1 none 10:0  483 81 60 1,170 0 Example 14 and 6* Comparative Resin 4 Resin 8 5:5 289 82 61 1,056 1 Example 15 Comparative Resin 2 Resin 7 5:5 522 82 62 1,091 0 Example 16 Comparative Resin 6 Resin 9 5:5 17 81 67 836 2 Example 17 *mixed at Resin 1: Resin 6 = 5:5

[0136] As shown in Table 4 above, in Examples, not only the electrodes had a higher peel strength and were less likely to be broken when cut, but also the batteries had a higher initial charge-discharge efficiency, a higher 5C discharge capacity retention rate, and a lower direct-current resistance, as compared to those of Comparative Examples.