Non-fluorine-based secondary batteries

Abstract

To provide a fluorine-free secondary battery that does not experience a decrease in electrochemical performance even without the use of fluorine-containing compounds. [Solution] The present invention relates to a non-fluorine secondary battery comprising a positive electrode capable of intercalating and releasing metal ions, a negative electrode capable of intercalating and releasing metal ions, a non-aqueous electrolyte containing a non-aqueous solution and an electrolyte dissolved in the non-aqueous solution, and a separation membrane, wherein the positive electrode, the negative electrode, the non-aqueous electrolyte, and the separation membrane do not contain fluorine atoms.

Description

[Technical Field]

[0001] This invention relates to a non-fluorinated secondary battery that does not contain fluorine atoms. [Background technology]

[0002] Lithium-ion batteries have high energy density and are widely used in the electrical, electronics, communications, and computer industries. Following their use in small lithium-ion batteries for portable electronic devices, their applications are expanding to include high-capacity batteries for hybrid and electric vehicles.

[0003] Currently, fluorine-containing compounds (such as PFAS (perfluoroalkyl and polyfluoroalkyl compounds)) are widely used in secondary batteries. Fluorine-containing compounds, with their excellent thermal stability and chemical resistance, are considered essential for high-voltage battery operation.

[0004] However, recently, due to bioaccumulation and toxicity, fluorine-containing compounds are being viewed as persistent organic pollutants, raising concerns about their impact on the environment and health. Strict environmental regulations on fluorine-containing compounds are expected to be imposed, and their exclusion from secondary battery development is being demanded. Furthermore, fluorine-containing compounds can also lead to a decrease in the performance of secondary batteries.

[0005] For example, fluorine-containing compounds such as poly(vinylidene fluoride) (PVDF) binders and lithium hexafluorophosphate (LiPF6) salts are widely used in secondary batteries as binders for the positive electrode and electrolyte, respectively.

[0006] Hydrophobic PVDF interacts with the surface of aluminum (Al) current collectors and hydrophilic positive electrode active material particles due to weak van der Waals forces, which can cause the active material to separate from the current collector and severely corrode the Al foil exposed to the electrolyte.

[0007] Furthermore, the defluorination of PVDF can occur due to the decomposition of alkaline LiOH or electrolytes by residual Li compounds on the surface of the positive electrode active material, generating toxic hydrofluoric acid (HF) and potentially causing gelation of the PVDF.

[0008] On the other hand, as unstable LiPF6 decomposes into LiOH and HF, a series of reactions, including the defluorination of PVDF, can be accelerated, potentially reducing the capacity of the secondary battery.

[0009] In addition, during battery recycling, the strong Li-F bonds in PVDF can hinder Li recovery, reducing recycling efficiency, and the thermal decomposition of the PVDF binder can generate dangerous by-products such as HF.

[0010] Therefore, there is currently a growing demand for the development of non-fluorine-based secondary batteries that do not cause environmental or safety problems and do not degrade the electrochemical performance of secondary batteries. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Republic of Korea Patent Publication No. 10-2024-0066611 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] Therefore, the present invention aims to provide a non-fluorine-based secondary battery that does not experience a decrease in electrochemical performance even without using fluorine-containing compounds.

[0013] Furthermore, since it does not use fluorine-containing compounds, the aim is to provide a sustainable, fluorine-free secondary battery that does not cause environmental or safety problems.

[0014] However, the problems to be solved by the present application are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0015] One aspect of the present application provides a non-aqueous secondary battery including a positive electrode capable of occluding and releasing metal ions, a negative electrode capable of occluding and releasing metal ions, a non-aqueous electrolyte including a non-aqueous solution and an electrolyte dissolved in the non-aqueous solution, and a separator, wherein the positive electrode, the negative electrode, the non-aqueous electrolyte, and the separator do not contain fluorine atoms. The present application provides a non-fluorine-based secondary battery.

[0016] Another aspect of the present application provides a non-fluorine-based polyamide polymer including a diamine monomer unit containing sulfone, a diamine monomer unit containing carboxylic acid, and a monomer unit containing at least one aromatic ring, which is a binder for a positive electrode, a binder for a negative electrode, a binder for a separator, or a binder for a plain coating. The present application provides a non-fluorine-based polyamide polymer.

Advantages of the Invention

[0017] The non-fluorine-based secondary battery of the present invention can exhibit excellent electrochemical characteristics without using a fluorine-containing compound.

[0018] In addition, since the non-fluorine-based secondary battery of the present invention does not use a fluorine-containing compound, it does not cause environmental and safety problems.

Modes for Carrying Out the Invention

[0019] Hereinafter, the operations and effects of the invention will be described in more detail through specific examples of the invention. However, such examples are merely shown as examples of the invention and do not define the scope of the invention.

[0020] Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0021] Therefore, the configurations of the embodiments described herein represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that, at the time of filing, there are various equivalents and modifications that can be substituted for these embodiments.

[0022] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “includes,” “equip,” or “have” are intended to specify the existence of an implemented feature, number, stage, component, or combination thereof, and should be understood not to preemptively exclude the possibility of the existence or addition of one or more other features, numbers, stages, components, or combinations thereof.

[0023] In this specification, the terms "from" and "~" in "a to b" and "a~b" which indicate a numerical range are defined as ≥ a and ≤ b.

[0024] A non-fluorine secondary battery according to one aspect of the present invention comprises a positive electrode capable of intercepting and releasing metal ions, a negative electrode capable of intercepting and releasing metal ions, a non-aqueous electrolyte containing a non-aqueous solution and an electrolyte dissolved in the non-aqueous solution, and a separation membrane, wherein the positive electrode, the negative electrode, the non-aqueous electrolyte, and the separation membrane do not contain fluorine atoms.

[0025] Specifically, the aforementioned non-fluorine-based secondary battery does not contain any detectable fluorine atoms when measured by XPS or SEM-EDS.

[0026] In other words, the positive electrode, negative electrode, non-aqueous electrolyte, and separation membrane of the non-fluorine secondary battery do not contain compounds containing fluorine atoms, so no fluorine atoms are detected when measured by XPS or SEM-EDS.

[0027] Furthermore, the non-fluorine-based secondary battery does not require that all components and materials included in the non-fluorine-based secondary battery, not just the positive electrode, negative electrode, non-aqueous electrolyte, and separation membrane, contain fluorine atoms, and no fluorine atoms are detected when measured by XPS or SEM-EDS.

[0028] On the other hand, the non-fluorine-based secondary battery does not generate HF gas during operation.

[0029] In other words, since the non-fluorine secondary battery does not contain compounds containing fluorine atoms such as PVDF and LiPF6, it can suppress the formation of C=C double bonds and the generation of HF gas under the basic conditions of PVDF, and it can also suppress the generation of HF gas due to the decomposition reaction of LiPF6 within the battery.

[0030] By suppressing HF gas generation, the problem of HF gas reacting with the CEI or SEI layer stably formed on the surface of the positive / negative electrode active material, leading to the leaching of transition metals and hindering battery performance, can be solved.

[0031] Furthermore, if the non-fluorine-based secondary battery is a full cell, it may have an initial charge capacity of 222 mAh / g or more, an initial discharge capacity of 186 mAh / g or more, and an initial efficiency of 83% or more.

[0032] For example, the initial charge capacity may be 222mAh / g or more and 230mAh / g or less, the initial discharge capacity may be 186mAh / g or more and 200mAh / g or less, and the initial efficiency may be 83% or more and 90% or less.

[0033] In addition, if the non-fluorine-based secondary battery is a full cell, the capacity retention rate after 100 charge-discharge cycles at room temperature (25°C) may be 89.5% or higher, and the capacity retention rate after 100 charge-discharge cycles at high temperature (45°C) may be 90% or higher.

[0034] For example, the capacity retention rate after 100 charge-discharge cycles at room temperature (25°C) may be 89.5% or more and 95% or less, and the capacity retention rate after 100 charge-discharge cycles at high temperature (45°C) may be 90% or more and 95% or less.

[0035] In one embodiment, the positive electrode may include a non-fluorinated polyamide polymer or copolymer, a non-fluorinated polyurethane polymer or copolymer, a non-fluorinated epoxy polymer or copolymer, a non-fluorinated polyimide polymer or copolymer, a non-fluorinated polyamide-imide polymer or copolymer, a non-fluorinated polyether-imide polymer or copolymer, a polyacrylate polymer or copolymer, or a combination thereof.

[0036] In one embodiment, the non-fluorinated polyamide polymer may include a diamine monomer unit containing a sulfone, a diamine monomer unit containing a carboxylic acid, and a monomer unit containing at least one aromatic ring.

[0037] The aforementioned non-fluorinated polyamide polymer does not necessarily have to contain aliphatic rings or aliphatic chain structures in its main chain (although it may contain aliphatic rings or aliphatic chain structures as terminal groups that are not part of the main chain).

[0038] When the non-fluorinated polyamide polymer contains aliphatic rings or aliphatic chain structures in its main chain, problems such as reduced electrode expansion and precipitation due to decreased solubility occur compared to the non-fluorinated polyamide polymer containing monomer units that include at least aromatic rings, which can increase the electrical resistance of the battery and make it difficult to use as a binder.

[0039] The electrode binder containing the aforementioned non-fluorinated polyamide polymer exhibits reduced swelling due to the electrolyte and superior electrolyte stability compared to existing electrode binders containing PVDF-based polymers. This also reduces cell volume expansion, improving battery stability and lifespan.

[0040] The non-fluorinated polyamide polymer does not contain fluorine atoms and does not generate hydrogen fluoride during the charging and discharging process of batteries in which the binder is used.

[0041] In contrast, currently commercialized PVDF-based binders contain fluorine atoms, which leads to the problem of hydrogen fluoride being generated during the battery's charging and discharging process.

[0042] On the other hand, the monomer unit containing the sulfone may also contain an aromatic ring. The sulfone and / or aromatic ring of the monomer unit containing the sulfone can be used to form part of the main chain of a nonfluorinated polyamide polymer. That is, the nonfluorinated polyamide polymer may contain a sulfone in its main chain.

[0043] The diamine monomer unit containing the carboxylic acid may contain one or more carboxylic acids, and the carboxylic acid may be a substituent of an aromatic ring.

[0044] When used in an appropriate amount, the diamine monomer units containing the carboxylic acid can improve the performance of batteries while enhancing the binding strength of non-fluorinated polyamide polymers.

[0045] The at least one aromatic ring can be used to form part of the backbone of the nonfluorinated polyamide polymer. That is, the nonfluorinated polyamide polymer may contain an aromatic ring in its backbone.

[0046] The monomer unit comprising at least one aromatic ring must be capable of polymerizing with a diamine monomer to produce a non-fluorinated polyamide polymer, and may contain substituents for this purpose.

[0047] In one embodiment, the monomers formed by polymerization of monomer units containing the sulfone are bis(4-aminophenyl)sulfone, bis(3-aminophenyl)sulfone, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene. 4-aminophenyl)sulfone)), 1,4-bis(4-aminophenylsulfone)benzene (1,4-bis(4-aminophenyl)sulfone)), bis[3-(3-aminophenoxy)phenyl]sulfone (bis[3-(3-aminophenoxy)phenyl]sulfone)), bis[3-(4-aminophenoxy)phenyl]sulfone (bis[3-(4-aminophenoxy)phenyl]sulfone)), bis[4-(3-aminophenoxy)phenyl]sulfone (bis[4-(3-aminophenoxy)phenyl]sulfone)), bis[4-(4-aminophenoxy)phenyl]sulfone (bis[4-(4-aminophenoxy)phenyl]sulfone)), or a combination thereof.

[0048] In particular, when bis(4-aminophenyl)sulfone is used, the bonding properties of non-fluorinated polyamide polymers can be greatly improved. Furthermore, it can significantly contribute to improving the characteristics of batteries using positive electrodes to which bis(4-aminophenyl)sulfone is applied (for example, the initial efficiency characteristics of the battery).

[0049] In one embodiment, the monomer used to polymerize the diamine monomer unit containing the carboxylic acid may be 3,5-diaminobenzoic acid (DABA).

[0050] The carboxylic acid of 3,5-diaminobenzoic acid can contribute to improving the binding force with the aluminum current collector.

[0051] In one embodiment, the monomer that polymerizes to form the monomer unit containing at least one aromatic ring may be a terephthaloyl chloride monomer, an isophthaloyl chloride monomer, a phthalic acid monomer, an isophthalic acid monomer, a terephthalic acid monomer, or a combination thereof.

[0052] In one embodiment, the molar ratio of terephthaloyl chloride to isophthaloyl chloride used in the polymerization of the nonfluorine-based polyamide polymer (mol% of terephthaloyl chloride:mol% of isophthaloyl chloride) may be 1:9 to 9:1.

[0053] For example, the molar ratio of terephthaloyl chloride to isophthaloyl chloride may be 8:2 to 2:8 or 3:7 to 7:3.

[0054] In other words, terephthaloyl chloride and isophthaloyl chloride can be used together for the polymerization of the non-fluorinated polyamide polymer of this application.

[0055] In one embodiment, the molar ratio of the sulfone-containing diamine monomer used in the polymerization of the nonfluorine-based polyamide polymer to the carboxylic acid-containing diamine monomer (mol% of the sulfone-containing diamine monomer:mol% of the carboxylic acid-containing diamine monomer units) may be 9.9:0.1 to 6:4.

[0056] For example, the molar ratio of the diamine monomer containing the sulfone to the diamine monomer containing the carboxylic acid may be 9.5:0.5~6:4, 9.5:0.5~7:3, 9.5:0.5~8:2, 9.0:1.0~6:4, 9.0:1.0~7:3, or 9.0:1.0~8:2.

[0057] If the content of the diamine monomer containing the carboxylic acid exceeds the content specified in this application, the diamine monomer containing the carboxylic acid has a lower molecular weight than the diamine monomer containing the sulfone, which can lead to a decrease in binding strength due to the limit of molecular weight increase, and thus a decrease in the performance of the secondary battery.

[0058] On the other hand, if the content of the diamine monomer containing the carboxylic acid falls below the content specified in this application, a decrease in binding strength may occur, which may degrade the performance of the secondary battery.

[0059] In one embodiment, the non-fluorinated polyamide polymer may contain monomer repeating units represented by the following chemical formula 1.

[0060] [ka]

[0061] In the above chemical formula 1, X1 comprises at least one aromatic ring substituted with a halogen element, hydrogen, a hydroxyl group, a carboxyl group, a linear or branched hydrocarbon group having 1 to 4 carbon atoms, or a combination thereof. X2 is two aromatic rings substituted with a halogen element, hydrogen, a hydroxyl group, a carboxyl group, a linear or branched hydrocarbon group having 1 to 4 carbon atoms, or a combination thereof, linked together by -SO2-; and A ring comprising an aromatic ring substituted with at least one carboxyl group; n+m=1 is also acceptable.

[0062] In the above chemical formula 1, n and m represent mole fractions.

[0063] The halogen element in the chemical formula 1 does not necessarily have to contain fluorine.

[0064] The monomer unit corresponding to X1 in the aforementioned chemical formula 1 can correspond to a monomer unit containing at least one aromatic ring.

[0065] For example, the monomer that polymerizes to form the monomer unit corresponding to X1 in the chemical formula 1 may be a terephthaloyl chloride monomer, an isophthaloyl chloride monomer, a phthalic acid monomer, an isophthalic acid monomer, a terephthalic acid monomer, or a combination thereof.

[0066] Furthermore, the monomer that forms the monomer unit corresponding to X2 in the above chemical formula 1 by polymerization may be a combination of a diamine monomer containing a sulfone and at least one aromatic ring, and a diamine monomer containing a carboxylic acid.

[0067] For example, a diamine monomer containing a sulfone that polymerizes to form a monomer unit corresponding to X2 in the above chemical formula 1, and at the same time containing at least one aromatic ring, is bis(4-aminophenyl)sulfone, bis(3-aminophenyl)sulfone, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone) )Benzene(1,3-bis(4-aminophenyl)sulfone)), 1,4-bis(4-aminophenylsulfone)benzene(1,4-bis(4-aminophenyl)sulfone)), bis[3-(3-aminophenoxy)phenyl]sulfone(bis[3-(3-aminophenoxy)phenyl]sulfone)), bis[3-(4-aminophenoxy)phenyl]sulfone(bis[3-(4-aminophenoxy)phenyl]sulfone)), bis[4-(3-aminophenoxy)phenyl]sulfone(bis[4-(3-aminophenoxy)phenyl]sulfone)), bis[4-(4-aminophenoxy)phenyl]sulfone(bis[4-(4-aminophenoxy)phenyl]sulfone)), or combinations thereof.

[0068] Furthermore, the diamine monomer containing a carboxylic acid that forms a monomer unit corresponding to X2 in the above chemical formula 1 by polymerization may be 3,5-diaminobenzoic acid.

[0069] In one embodiment, the weight-average molecular weight of the non-fluorinated polyamide polymer may be 100,000 or more and 1,000,000 or less.

[0070] Within the range of weight-average molecular weight of the non-fluorinated polyamide polymer of this application, the higher the weight-average molecular weight, the higher the binding strength of the non-fluorinated polyamide polymer may be.

[0071] If the weight-average molecular weight of the non-fluorinated polyamide polymer is less than 100,000, the stability of the electrolyte of the electrode binder containing the non-fluorinated polyamide polymer may decrease. Furthermore, the stability of the electrode slurry containing the binder containing the non-fluorinated polyamide polymer may also decrease.

[0072] On the other hand, if the weight-average molecular weight of the non-fluorinated polyamide polymer exceeds 1,000,000, the viscosity may become high during slurry production, making slurry coating difficult.

[0073] In one embodiment, the non-fluorinated polyamide polymer may be a binder for the positive electrode, a binder for the negative electrode, a binder for the separation membrane, or a binder for coating the plain area (non-coated area).

[0074] In one embodiment, the non-fluorine secondary battery may include a positive electrode in which a positive electrode active material layer is formed by applying a positive electrode slurry containing a binder solution comprising the positive electrode binder and the positive electrode active material.

[0075] The positive electrode active material used in this application can be any non-fluorine positive electrode active material that does not contain any fluorine atoms and is available in the art. Specific examples of such positive electrode active materials include lithium metal; lithium cobalt oxides such as LiCoO2; Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxides such as Li2CuO2; vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; LiNi 1-x M xLithium nickel-based oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); LiMn 2-x M x Lithium manganese composite oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); Li(Ni a Co b Mn c )O2 (where 0 < a < 1, 0 < b < 1, 0 < c < 1, and a + b + c = 1); sulfur or disulfide compound; phosphates such as LiFePO4, LiMnPO4, LiCoPO4, LiNiPO4; Fe2(MoO4)3, etc., but not limited thereto.

[0076] At this time, the positive electrode active material layer may additionally contain a non-fluorine-based dispersant, a conductive material, a filler, and other additives that do not contain fluorine atoms in addition to the positive electrode active material.

[0077] The positive electrode active material may be contained in an amount of 90 to 99% by weight based on the solid content. If the content of the active material is low, the battery cannot achieve a high capacity. If the content of the active material is excessively high, the contents of the binder, the conductive material, etc. will be relatively reduced, so the electrode adhesion, conductivity, etc. may decrease.

[0078] The conductive material is not particularly limited and can be appropriately selected according to the types of batteries and capacitors. For example, in the case of a lithium-ion secondary battery, carbon such as graphite and activated carbon is used. In the case of a nickel-hydrogen secondary battery, cobalt oxide can be used, and for the negative electrode, nickel powder, cobalt oxide, titanium oxide, carbon, etc. can be used.

[0079] Examples of the carbon include acetylene black, furnace black, graphite, carbon fiber, fullerenes, and carbon nanotubes.

[0080] The amount of conductive material used is usually 1 to 20 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the electrode active material.

[0081] Reducing the content of conductive material and increasing the content of positive electrode active material improves the energy density of the secondary battery; therefore, it is important to achieve high efficiency even when using the same amount of conductive material.

[0082] The smaller and more uniformly dispersed the conductive material used in electrode slurries for secondary batteries, the higher the conductivity, reducing resistance within the battery, resulting in improved power output and extended battery life. Conversely, if the material is large and unevenly dispersed, even with the same amount, the binding properties and conductivity will be lower, negatively impacting the battery's lifespan and power output. Furthermore, lower viscosity of the dispersion allows for a higher solid content in the slurry, thereby increasing the electrode production rate.

[0083] As a binder for the positive electrode of a secondary battery, in addition to the positive electrode binder containing the non-fluorinated polyamide polymer of this application, one or more of the following non-fluorinated polymers that do not contain fluorine atoms may be selected and used together: poly(meth)acrylic acid, poly(meth)acrylamide, carboxymethylcellulose, poly(vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), poly(ethyl acrylate), polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and copolymers thereof.

[0084] The content of the binder in the positive electrode slurry composition is preferably 0.3 wt% to 10 wt%, and more preferably 0.7 wt% to 8 wt%, based on solid content. If the content is less than 0.3 wt%, it is difficult to expect sufficient binding force between the current collector and the electrode composition, and if the content exceeds 10 wt%, the proportion of binder in the electrode slurry composition increases, which may reduce the battery capacity.

[0085] In one embodiment, the positive electrode of the non-fluorine secondary battery may include a current collector and a positive electrode active material layer formed on the current collector, which includes the positive electrode binder of the present invention.

[0086] The positive electrode can be manufactured by (a) manufacturing a composition for forming a positive electrode active material layer, which includes a positive electrode active material and the binder of this application, and (b) applying the composition for forming a positive electrode active material layer onto a positive electrode current collector and then drying it.

[0087] The composition for forming the positive electrode active material layer can be mixed using a conventional mixer, such as a high-speed shear mixer or homomixer, in a conventional manner.

[0088] Step (b) is a step of manufacturing a positive electrode for a lithium secondary battery by applying the positive electrode active material layer forming composition manufactured in step (a) onto a positive electrode current collector and then drying it.

[0089] At this time, there are no limitations on the method of applying the slurry-like composition for forming the positive electrode active material layer. For example, it can be manufactured by methods such as doctor blade coating, dip coating, gravure coating, slit die coating, spin coating, comma coating, bar coating, reverse roll coating, screen coating, and cap coating.

[0090] After coating, drying allows for the formation of a positive electrode for secondary batteries (especially lithium secondary batteries) with a positive electrode active material layer.

[0091] The current collector can be any material that is conductive and does not chemically react with the electrode forming slurry. Typical examples include aluminum foil and copper foil. Current collectors with a thickness of 3 to 50 micrometers can be selected and used.

[0092] In one embodiment, the negative electrode may contain a non-fluorinated polymer that does not contain fluorine atoms. In particular, the non-fluorinated polymer of the negative electrode may be an aqueous polymer.

[0093] In one embodiment, the non-fluorinated polymer of the negative electrode may include styrene-butadiene rubber (SBR) or its copolymer, carboxymethyl cellulose (CMC) or its copolymer, polyacrylic acid (PAA) or its copolymer, metal polyacrylic acid (Metal-PAA) or its copolymer, poly(vinyl acetate) or its copolymer, polymethacrylic acid or its copolymer, polymethyl methacrylate or its copolymer, polymethacrylamide or its copolymer, polyacrylonitrile (PAN) or its copolymer, polymethacrylonitrile or its copolymer, polyimide (PI) or its copolymer, chitosan or its copolymer, starch or its copolymer, polyvinylpyrrolidone or its copolymer, polyethylene or its copolymer, polypropylene or its copolymer, ethylene-propylene-diene polymer (EPDM) or its copolymer, sulfonated EPDM or its copolymer, hydroxypropyl cellulose or its copolymer, regenerated cellulose or its copolymer, or a combination thereof.

[0094] For example, the non-fluorinated polymer of the negative electrode may contain styrene-butadiene rubber (SBR) and carboxymethylcellulose (CMC), and the weight ratio of styrene-butadiene rubber to carboxymethylcellulose (weight of styrene-butadiene rubber:weight of carboxymethylcellulose) may be 0.5 to 5:1.

[0095] If the weight ratio of styrene-butadiene rubber to carboxymethylcellulose exceeds the range of this application, it becomes difficult to achieve the desired battery capacity, and if it falls below the range of this application, the bonding strength of the electrodes may decrease.

[0096] In one embodiment, the non-fluorinated polymer of the negative electrode may be a binder for the negative electrode.

[0097] In one embodiment, the non-fluorine-based secondary battery may include a negative electrode in which a negative electrode active material layer is formed by applying a negative electrode slurry including a binder solution including the binder for the negative electrode and the negative electrode active material.

[0098] The negative electrode active material may be a compound including one or more selected from the group consisting of a non-fluorine-based carbon-based material not including a fluorine atom, silicon, an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, and a rare earth element, and preferably may be silicon or a compound including silicon.

[0099] Examples of the carbon-based material include, but are not limited to, artificial graphite, natural graphite, hard carbon, soft carbon, etc. The negative electrode active material including silicon is not particularly limited as long as it is silicon or a compound including silicon, and preferably is one or more selected from the group consisting of Si, SiO x (0 < x < 2), a Si-Y alloy (where Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, and is not Si), and a Si-C composite.

[0100] For example, the carbon-based material may include artificial graphite and natural graphite, and the weight ratio of artificial graphite to natural graphite (weight of artificial graphite: weight of natural graphite) may be 1 to 9.5:1.

[0101] Also, when using a mixture of a negative electrode active material including silicon and another negative electrode active material as the negative electrode active material, the negative electrode active material including silicon may be included at 8% by weight or more of the total weight of the negative electrode active material.

[0102] The negative electrode active material may be included at 50 to 98% by weight based on the total weight of the negative electrode active material layer.

[0103] If the negative electrode active material is present in an amount of less than 50% by weight, the energy density decreases, making it impossible to manufacture a high-energy-density battery. If it is present in an amount exceeding 98% by weight, the content of conductive material and binder decreases, reducing electrical conductivity and potentially decreasing the adhesive strength between the electrode active material layer and the current collector.

[0104] On the other hand, the negative electrode binder may be present in an amount of 1 to 35% by weight relative to the total weight of the negative electrode slurry. If the negative electrode binder is less than 1% by weight, the physical properties of the negative electrode may deteriorate, causing the negative electrode active material and conductive material to detach. If it exceeds 35% by weight, the ratio of negative electrode active material to conductive material may decrease relatively, reducing the battery capacity and potentially lowering the electrical conductivity of the negative electrode.

[0105] The negative electrode may include a current collector and a negative electrode active material layer formed on the current collector, which includes the negative electrode binder.

[0106] The negative electrode active material layer may additionally contain a non-fluorinated conductive material that does not contain fluorine atoms. The conductive material is used to further improve the conductivity of the negative electrode active material. Such a conductive material is not particularly limited as long as it does not contain fluorine atoms and is conductive without inducing a chemical change in the battery, and examples of usable materials include graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives.

[0107] The conductive material may be present in an amount of 0.05 to 30% by weight, preferably 15 to 25% by weight, relative to the total weight of the negative electrode active material layer. If the conductive material is present in an amount of less than 0.05% by weight, the electrical conductivity of the negative electrode will be low. If it is present in an amount exceeding 30% by weight, the ratio of silicon-based negative electrode active material to binder will decrease relatively, reducing the battery capacity. In order to maintain the negative electrode active material layer, the binder content must be increased, which reduces the negative electrode active material content and makes it impossible to manufacture a battery with high energy density.

[0108] The negative electrode, by including the negative electrode active material layer with the negative electrode binder, can suppress the volume expansion of the negative electrode active material that occurs during charging and discharging of the secondary battery, thereby improving the capacity retention rate per cycle.

[0109] The negative electrode can be manufactured by (a) manufacturing a composition for forming a negative electrode active material layer, which includes a negative electrode active material and a negative electrode binder, and (b) applying the composition for forming a negative electrode active material layer onto a negative electrode current collector and then drying it.

[0110] The negative electrode active material layer forming composition is manufactured in a negative electrode slurry state, and the solvent used for manufacturing in the slurry state must be easily dried, and it is most preferable that the solvent can dissolve the negative electrode binder well while maintaining the negative electrode active material in a dispersed state without dissolving it.

[0111] The solvent according to this application may be water or a non-fluorinated organic solvent that does not contain fluorine atoms, and the organic solvent may include one or more selected from the group consisting of methylpyrrolidone, dimethylformamide, isopropyl alcohol, acetonitrile, methanol, ethanol, and tetrahydrofuran.

[0112] The composition for forming the negative electrode active material layer can be mixed using a conventional mixer, such as a late mixer, a high-speed shear mixer, or a homomixer, in a conventional manner.

[0113] Step (b) is a step of manufacturing a negative electrode for a lithium secondary battery by applying the negative electrode active material layer forming composition manufactured in step (a) onto the negative electrode current collector and then drying it.

[0114] The negative electrode current collector may be selected from the group consisting of non-fluorine materials that do not contain fluorine atoms, such as copper, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof. The stainless steel may be surface-treated with carbon, nickel, titanium, or silver, and as the alloy, an aluminum-cadmium alloy can be used. In addition, calcined carbon that does not contain fluorine atoms, non-conductive polymers surface-treated with conductive materials, or conductive polymers may be used.

[0115] The negative electrode active material layer forming composition manufactured in step (a) above is applied to the negative electrode current collector and can be coated onto the current collector with an appropriate thickness depending on the thickness to be formed, preferably within the range of 10 to 300 μm.

[0116] At this time, there are no limitations on the method of applying the slurry-like negative electrode active material layer forming composition. For example, it can be manufactured by methods such as doctor blade coating, dip coating, gravure coating, slit die coating, spin coating, comma coating, bar coating, reverse roll coating, screen coating, and cap coating.

[0117] After coating, drying allows for the formation of a negative electrode for secondary batteries (especially lithium secondary batteries) with a negative electrode active material layer.

[0118] In one embodiment, the electrolyte of the non-aqueous electrolyte can include a non-fluorinated lithium salt.

[0119] The aforementioned non-fluorinated lithium salts include lithium perchlorate (LiClO4, Lithium perchlorate), LiCl, LiBr, LiI, LiClO4, and LiB. 10 Cl 10 These may be LiAlCl4, LiSCN, LiC4BO8, LiCH3SO3, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenylborate imide, or a combination thereof.

[0120] For example, the non-fluorinated lithium salt may be lithium perchlorate (LiClO4).

[0121] In one embodiment, the non-aqueous electrolyte solution is a non-fluorinated solution that does not contain fluorine atoms, such as vinylene carbonate, propylene sulfone, and lithium bisoxalate borate. This may include bisoxalatoborate (LiBOB), N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfuran (franc), 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, ethyl propionate, or combinations thereof.

[0122] For example, the non-aqueous solution may contain ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate, in which case the volume ratio or weight ratio of ethylene carbonate:ethyl methyl carbonate:dimethyl carbonate may be 1:0 to 2:0 to 2.

[0123] In particular, the ratio of ethylene carbonate:ethyl methyl carbonate:dimethyl carbonate may be 1:1:1.

[0124] If the ethylene carbonate content exceeds the scope of this application, the mobility of the lithium salt may decrease due to high viscosity.

[0125] On the other hand, if the content ratio of ethyl methyl carbonate and dimethyl carbonate exceeds the scope of this application, decomposition of the lithium salt may become difficult.

[0126] Furthermore, the non-aqueous solution may include vinylene carbonate, propylene sulfone, lithium bisoxalate borate, or a combination thereof.

[0127] In this case, vinylene carbonate and propylene sulfone may each be present in an amount of 1 to 5 wt% of the total weight of the non-fluorinated electrolyte.

[0128] If the content of vinylene carbonate and propylene sulfone falls below the scope of this application, the initial charge capacity, initial discharge capacity, and initial efficiency of the battery may decrease. If it exceeds the scope of this application, side reactions may reduce the battery's cycle and capacity characteristics.

[0129] Furthermore, lithium bisoxalate borate may be included in the total weight of the non-fluorinated electrolyte at a concentration of 0.01 to 1 wt%.

[0130] If the lithium bisoxalate borate content falls outside the scope of this invention, the battery's cycle maintenance characteristics and high-temperature stability characteristics may deteriorate.

[0131] On the other hand, the electrolyte may include a non-fluorinated organic solid electrolyte, an inorganic solid electrolyte, or a combination thereof, that does not contain fluorine atoms.

[0132] Examples of the organic solid electrolytes that can be used include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfides, polyvinyl alcohols, and polymers containing secondary dissociation groups.

[0133] Examples of the inorganic solid electrolytes that can be used include lithium nitrides, halides, and sulfates such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2.

[0134] Furthermore, non-aqueous electrolytes may contain non-fluorinated or other additives that do not contain fluorine atoms, for the purpose of improving charge / discharge characteristics, flame retardancy, etc. Examples of such additives include pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, n-glyme, hexaphosphate triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride, propensultone (PRS), and the like.

[0135] In one embodiment, the separation membrane may be a porous substrate made of one or more selected from the group consisting of polyethylene, polypropylene, polybutylene, polypentene, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalate, which are nonfluorinated materials that do not contain fluorine atoms.

[0136] The separation membrane must be an insulator so as to separate the negative electrode and the positive electrode, and provide a passage through which only lithium ions can move.

[0137] To achieve this, the electrolyte must have good wettability, and a coating separation membrane coated with ceramic or other material that enhances heat resistance and mechanical strength to prevent short circuits in the battery can be used. This coating may be in single or multilayer form.

[0138] The separation membrane may be made of a porous substrate.

[0139] The lithium secondary battery according to the present invention can undergo processes other than the common winding process, such as lamination stacking and folding of the separation membrane and electrodes. The battery case may be cylindrical, rectangular, pouch-type, or coin-type.

[0140] The present application will be described in more detail below using examples, but the application is not limited thereto.

[0141] Manufacturing Example 1: Production of non-fluorinated polyamide polymer binders In a 500 ml four-necked flask under a nitrogen atmosphere, N-methyl-2-pyrrolidone (NMP), bis(4-aminophenyl)sulfone (p-APS), a monomer that forms monomer units containing sulfone, and 3,5-diaminobenzoic acid (DABA), a diamine monomer containing carboxylic acid, were added and stirred.

[0142] The molar ratio of bis(4-aminophenyl)sulfone to 3,5-diaminobenzoic acid was 9:1.

[0143] Afterward, the internal temperature of the reactor was lowered to below 5°C, and then isophthaloyl chloride (IPC), a monomer unit containing an aromatic ring, was added and the reaction was carried out.

[0144] To this, terephthaloyl chloride (TPC), a monomer that forms monomer units containing aromatic rings, was added and the mixture was stirred for a sufficient amount of time.

[0145] The molar ratio of isophthaloyl chloride to terephthaloyl chloride was 3:7.

[0146] An olefin-based neutralizing agent was added to the solution after its viscosity had increased to a certain level, and the mixture was stirred to remove the HCl generated during the synthesis process.

[0147] Finally, a non-fluorinated polyamide copolymer solution for use as a binder was prepared, with a solid content concentration of 15% by weight.

[0148] Manufacturing Example 2. Manufacturing of non-fluorine-based cathode slurry and cathode. A cathode active material slurry composition with a solid content of 70% by weight was prepared by mixing 97.5% by weight of NCM811 as the electrode active material, 2% by weight of a non-fluorinated polyamide polymer binder produced according to Production Example 1, 0.5% by weight of a carbon nanotube (CNT) dispersion, and the remainder of NMP.

[0149] On the other hand, the positive electrode active material slurry composition may contain 96% to 98% by weight of the electrode active material, 1% to 3% by weight of the non-fluorinated polyamide polymer binder, and 0.5% to 1% by weight of a CNT dispersion. Furthermore, the solid content of the positive electrode active material slurry composition may be 60% to 75% by weight.

[0150] The manufactured positive electrode slurry composition was coated onto an aluminum (Al) foil positive electrode current collector with a thickness of 20 μm using an applicator, dried in a circulating oven at 130°C for 1 hour, and then rolled in a roll press to produce the positive electrode.

[0151] Manufacturing Example 3. Manufacturing of non-fluorine-based anode slurry and anode A negative electrode slurry was prepared by mixing artificial graphite and natural graphite as electrode active materials, styrene-butadiene rubber (SBR) and carboxymethylcellulose (CMC) as binders, with a total solid content of 100 parts by weight of slurry as the base, and then adding distilled water to adjust the solid content of the slurry to 50% by weight.

[0152] At this time, the weight percentages of artificial graphite, natural graphite, SBR, and CMC were 85 wt, 10 wt%, 3 wt%, and 2 wt%, respectively.

[0153] The prepared negative electrode slurry was uniformly applied onto a copper current collector, dried at 110°C, and the resulting mixture was rolled using a roll press. The negative electrode was then manufactured by heating it in a vacuum oven at 110°C for more than 4 hours.

[0154] Manufacturing Example 4. Manufacturing of Non-Fluorine Electrolytes [Manufacturing Example 4-1] In a vial, organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) were added in a 1:1:1 (v:v:v) ratio. After adding 1 mol / L of lithium LiClO4 salt, the mixture was stirred at room temperature to dissolve.

[0155] Subsequently, the mixture was dissolved by adding 1 wt% each of the additives vinylene carbonate (VC) and propylene sulfone (PS), and 0.1 wt% of lithium bisoxalatoborate (LiBOB).

[0156] [Manufacturing Example 4-2] The electrolyte was prepared in the same manner as in Production Example 4-1, except that the additive lithium bisoxalate borate was not added.

[0157] [Manufacturing Example 4-3] The electrolyte was prepared in the same manner as in Production Example 4-1, except that the additives propylene sulfone and lithium bisoxalate borate were not added.

[0158] Manufacturing Example 5. Cell Manufacturing [Manufacturing Example 5-1] Manufacturing of half cells A lithium secondary battery was manufactured using the positive electrode plate produced according to the above manufacturing example 2, with a polyolefin separation membrane interposed between the positive electrode and the lithium metal, without classifying the form into 2032 coin cells or pouch type.

[0159] In this case, the electrolyte solution produced according to Production Example 4 was used.

[0160] [Manufacturing Example 5-2] Manufacturing of full cells A polyolefin separation membrane was interposed between the positive electrode, which used the positive electrode plate manufactured according to Manufacturing Example 2, and the negative electrode, which was manufactured according to Manufacturing Example 3. A lithium secondary battery was then manufactured without classifying it into either a 2032 coin cell or a pouch type.

[0161] In this case, the electrolyte solution produced according to Production Example 4 was used.

[0162] Examples and Comparative Examples [Example 1] The electrolyte solution from Production Example 4-1 was used as the electrolyte, and the cell was manufactured according to Production Example 5-1.

[0163] [Example 2] The electrolyte solution from Production Example 4-1 was used as the electrolyte, and the cell was manufactured according to Production Example 5-2.

[0164] [Example 3] The electrolyte solution from Production Example 4-2 was used as the electrolyte, and the cell was manufactured according to Production Example 5-2.

[0165] [Example 4] The electrolyte solution from Production Example 4-3 was used as the electrolyte, and the cell was manufactured according to Production Example 5-2.

[0166] [Comparative Example 1] A cell was manufactured in the same manner as in Example 1, except that a PVDF binder (weight-average molecular weight: 1,000,000, melting point: 150-160°C, glass transition temperature: -40°C, Solvay) was used instead of the non-fluorinated polyamide polymer binder in Manufacturing Example 1, and the cathode slurry and cathode manufactured in Manufacturing Example 2 were used.

[0167] [Comparative Example 2] The cells were manufactured in the same manner as in Example 1, except that an electrolyte containing a fluorinated compound was used instead of the non-fluorinated electrolyte in Manufacturing Example 4.

[0168] The electrolyte containing the aforementioned fluorine-based compound was a non-aqueous electrolyte to which LiPF61M, fluoroethylene carbonate (FEC) 1 wt%, propylene sulfone 1 wt%, and LiPO2F2 1 wt% were added.

[0169] [Comparative Example 3] A cell was manufactured in the same manner as in Example 1, except that a PVDF binder was used instead of the non-fluorinated polyamide polymer binder in Manufacturing Example 1, and the cathode slurry and cathode manufactured in Manufacturing Example 2 were used, and an electrolyte containing a fluorinated compound was used instead of the non-fluorinated electrolyte in Manufacturing Example 4.

[0170] The electrolyte containing the aforementioned fluorine-based compound was a non-aqueous electrolyte to which LiPF61M, fluoroethylene carbonate 1 wt%, propylene sulfone 1 wt%, and LiPO2F2 1 wt% were added.

[0171] [Comparative Example 4] The cell was manufactured in the same manner as in Example 2, except that a PVDF binder was used instead of the non-fluorinated polyamide polymer binder used in Manufacturing Example 1, and the cathode slurry and cathode manufactured in Manufacturing Example 2 were used.

[0172] [Comparative Example 5] The cells were manufactured in the same manner as in Example 2, except that an electrolyte containing a fluorinated compound was used instead of the non-fluorinated electrolyte in Manufacturing Example 4.

[0173] The electrolyte containing the aforementioned fluorine-based compound was a non-aqueous electrolyte to which LiPF61M, fluoroethylene carbonate 1 wt%, propylene sulfone 1 wt%, and LiPO2F2 1 wt% were added.

[0174] [Comparative Example 6] A cell was manufactured in the same manner as in Example 2, except that a PVDF binder was used instead of the non-fluorinated polyamide polymer binder in Manufacturing Example 1, and the cathode slurry and cathode manufactured in Manufacturing Example 2 were used, and an electrolyte containing a fluorinated compound was used instead of the non-fluorinated electrolyte in Manufacturing Example 4.

[0175] The electrolyte containing the aforementioned fluorine-based compound was a non-aqueous electrolyte to which LiPF61M, fluoroethylene carbonate 1 wt%, propylene sulfone 1 wt%, and LiPO2F2 1 wt% were added.

[0176] The manufacturing methods for the positive electrode, negative electrode, electrolyte, and cell of Examples 1-4 and Comparative Examples 1-6 are shown in Table 1 below.

[0177] [Table 1]

[0178] Evaluation Example 1: Measurement of the presence or absence of HF gas generation. A PVDF binder and the non-fluorinated polyamide polymer binder of Production Example 1 were immersed in an electrolyte containing a fluorinated compound to which LiPF61M, 1 wt% fluoroethylene carbonate, 1 wt% propylene sulfone, and 1 wt% LiPO2F2. After standing at 45°C for 24 hours, the color change was observed visually, and the change in pH was measured using litmus paper.

[0179] Furthermore, the PVDF binder and the non-fluorinated polyamide polymer binder from Production Example 1 were immersed in the non-fluorinated electrolyte of Production Example 4-1 and left at 45°C for 24 hours. At the same time, the color change was observed visually, and the change in pH was measured using litmus paper.

[0180] When a PVDF binder was immersed in an electrolyte containing a fluorine-based compound, a yellowing color was observed, and the pH was measured to be 2.

[0181] This is because HF gas was generated due to the formation of double bonds in PVDF and the decomposition of LiPF6.

[0182] On the other hand, when the non-fluorinated polyamide polymer binder of Production Example 1 was immersed in an electrolyte containing a fluorinated compound, there was no color change, and the pH was measured to be 6.

[0183] Furthermore, when the PVDF binder and the non-fluorinated polyamide polymer binder from Production Example 1 were immersed in the non-fluorinated electrolyte of Production Example 4-1, no color change occurred in either case, and the pH was measured to be 6.

[0184] In other words, when using the non-fluorinated polyamide polymer binder of Production Example 1 or the non-fluorinated electrolyte of Production Example 4-1, the generation of HF gas could be prevented.

[0185] Evaluation Example 2: Measurement of Half-Cell Performance The cells of Example 1 and Comparative Examples 1-3 were charged to 4.2V at a rate of 0.1C in CC / CV mode, then discharged to 2.8V at a rate of 0.1C, then charged to 4.2V at a rate of 0.2C, then discharged to 2.8V at a rate of 0.2C, then charged to 4.2V at a rate of 0.5C, and finally discharged to 2.8V at a rate of 0.5C (initial formation). At this time, the chamber temperature was 25°C. The "C" above represents the cell discharge rate, which is the value obtained by dividing the total capacity of the cell by the total discharge time.

[0186] The measurement results for the initial charge capacity, initial discharge capacity, and initial efficiency of the cells in Example 1 and Comparative Examples 1-3 are shown in Table 2 below.

[0187] During the initial formation, the charging capacity when charging at a rate of 0.1C up to 4.2V and the discharge capacity when discharging at a rate of 0.1C up to 2.8V were measured as the initial charging capacity and initial discharge capacity, respectively, and the initial efficiency was calculated using the following formula 1.

[0188] [Formula 1] Initial efficiency [%] = [Initial discharge capacity / Initial charge capacity] × 100

[0189] [Table 2]

[0190] As shown in Table 2 above, the cell of Example 1, which used a non-fluorinated cathode, a non-fluorinated polyamide polymer cathode binder, and a non-fluorinated electrolyte, showed the best initial charge capacity characteristics and initial discharge capacity characteristics compared to the cell of Comparative Example 1, which was manufactured using fluorinated PVDF, the cell of Comparative Example 2, which used a fluorinated electrolyte, and Comparative Example 3, which used PVDF and a fluorinated electrolyte.

[0191] Furthermore, the initial efficiency characteristics of the cell in Example 1 were superior to those of the cells in Comparative Examples 2 and 3, and were at the same level as the cell in Comparative Example 1.

[0192] In other words, we were able to confirm that non-fluorinated electrolytes can replace fluorinated electrolytes and provide cells with equivalent or superior properties, and that non-fluorinated binders can also replace fluorinated binders and provide cells with equivalent or superior properties.

[0193] In particular, we were able to confirm that non-fluorine-based secondary batteries can improve upon the problems of side reactions caused by fluorine functional groups and Li-ion migration within the battery compared to fluorine-based secondary batteries.

[0194] Evaluation Example 3: Measurement of Full Cell Performance The initial charge capacity, initial discharge capacity, and initial efficiency of the cells in Examples 2-4 and Comparative Examples 4-6 were measured using the same method as in Evaluation Example 2 and are shown in Table 3 below.

[0195] [Table 3]

[0196] As shown in Table 3 above, in the cells of Examples 3 and 4, when lithium bisoxalate borate and / or propylene sulfone were not added to the non-fluorine electrolyte, it was confirmed that the initial charge capacity, initial discharge capacity, and initial efficiency of the cells were slightly lower compared to Example 2.

[0197] On the other hand, the cell of Comparative Example 4, which differed from the cell of Example 2 only in that it used a fluorine-based cathode instead of a non-fluorine-based cathode, had a slightly higher initial charge capacity compared to the cell of Example 2, but its initial discharge capacity and initial efficiency were lower.

[0198] Furthermore, the cell of Comparative Example 5, which differed from the cell of Example 2 only in that it used a fluorinated electrolyte instead of a non-fluorinated electrolyte, showed a decrease in initial charge capacity, initial discharge capacity, and initial efficiency compared to the cell of Example 2.

[0199] In addition, the cell of Comparative Example 6, which differed from the cell of Example 2 only in that it used a fluorinated cathode instead of a non-fluorinated cathode and a fluorinated electrolyte instead of a fluorinated electrolyte, also showed a decrease in initial charge capacity, initial discharge capacity, and initial efficiency compared to the cell of Example 2.

[0200] Evaluation Example 4. Measurement of Volume Retention Rate The cells of Example 2 and Comparative Examples 4-6 were charged and discharged twice in CC / CV mode at 25°C with a charge / discharge current density of 0.1C, a charge termination voltage of 4.2V, and a discharge termination voltage of 2.8V.

[0201] Subsequently, 100 charge-discharge cycles were performed in CC / CV mode with a charge / discharge current density of 1C, a charge termination voltage of 4.2V, and a discharge termination voltage of 2.8V, and the capacity retention rate was measured.

[0202] At this time, the chamber temperature was adjusted to room temperature (25°C) and high temperature (45°C), respectively, and the room temperature capacity retention rate and high temperature capacity retention rate are shown in Table 4 below.

[0203] All discharges were performed under constant current / constant voltage conditions, and the termination current for constant voltage discharges was set to 0.005C.

[0204] At this time, the capacity retention rate was calculated using the following formula 2. [Formula 2] Capacity retention rate (%) = (Discharge capacity after 100 cycles / Discharge capacity after 1 cycle) × 100

[0205] [Table 4]

[0206] As shown in Table 4 above, the cell of Comparative Example 4, which differs from the cell of Example 2 only in that it uses a fluorine-based cathode instead of a non-fluorine-based cathode, showed a decrease in capacity retention at both room temperature and high temperature compared to the cell of Example 2.

[0207] Furthermore, the cell in Comparative Example 5, which differed from the cell in Example 2 only in that it used a fluorinated electrolyte instead of a non-fluorinated electrolyte, also showed a decrease in capacity retention at both room temperature and high temperature compared to the cell in Example 2.

[0208] On the other hand, the cell of Comparative Example 6, which differs from the cell of Example 2 only in that it uses a fluorinated cathode instead of a non-fluorinated cathode and a fluorinated electrolyte instead of a fluorinated electrolyte, also showed a decrease in capacity retention at both room temperature and high temperature compared to the cell of Example 2.

[0209] As a result, it was confirmed that the non-fluorine secondary battery of this application, which does not contain fluorine atoms, exhibits the same or improved electrochemical performance as a fluorine-based secondary battery containing fluorine atom compounds.

[0210] Furthermore, we were able to confirm that the non-fluorine-based secondary battery of this application is a sustainable secondary battery that does not cause environmental and safety problems associated with the use of fluorine atom compounds.

[0211] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

1. A positive electrode capable of intercalating and releasing metal ions, A negative electrode capable of intercalating and releasing metal ions, A non-aqueous solution and a non-aqueous electrolyte containing an electrolyte dissolved in the non-aqueous solution, A separation membrane and, The positive electrode, the negative electrode, the non-aqueous electrolyte, and the separation membrane do not contain fluorine atoms. Non-fluorine-based rechargeable batteries.

2. The positive electrode includes a non-fluorinated polyamide polymer or copolymer, a non-fluorinated polyurethane polymer or copolymer, a non-fluorinated epoxy polymer or copolymer, a non-fluorinated polyimide polymer or copolymer, a non-fluorinated polyamide-imide polymer or copolymer, a non-fluorinated polyether-imide polymer or copolymer, a polyacrylate polymer or copolymer, or a combination thereof. A non-fluorine-based secondary battery according to claim 1.

3. The non-fluorinated polyamide polymer comprises a diamine monomer unit containing a sulfone, a diamine monomer unit containing a carboxylic acid, and a monomer unit containing at least one aromatic ring. The non-fluorine-based secondary battery according to claim 2.

4. The non-fluorinated polyamide polymer is used as a binder for the positive electrode, a binder for the negative electrode, a binder for the separation membrane, or a binder for coating a plain area. The non-fluorine-based secondary battery according to claim 3.

5. The negative electrode contains a non-fluorinated polymer. A non-fluorine-based secondary battery according to claim 1.

6. The non-fluorinated polymer includes styrene-butadiene rubber (SBR) or its copolymer, carboxymethylcellulose (CMC) or its copolymer, polyacrylic acid (PAA) or its copolymer, metal polyacrylic acid (Metal-PAA) or its copolymer, poly(vinyl acetate) or its copolymer, polymethacrylic acid or its copolymer, polymethyl methacrylate or its copolymer, polymethacrylamide or its copolymer, polyacrylonitrile (PAN) or its copolymer, polymethacrylonitrile or its copolymer, polyimide (PI) or its copolymer, chitosan or its copolymer, starch or its copolymer, polyvinylpyrrolidone or its copolymer, polyethylene or its copolymer, polypropylene or its copolymer, ethylene-propylene-diene polymer (EPDM) or its copolymer, sulfonated EPDM or its copolymer, hydroxypropylcellulose or its copolymer, regenerated cellulose or its copolymer, or combinations thereof. The non-fluorine-based secondary battery according to claim 5.

7. The electrolyte of the non-aqueous electrolyte contains a non-fluorinated lithium salt. A non-fluorine-based secondary battery according to claim 1.

8. The non-fluorine-based lithium salt is lithium perchlorate (LiClO 4 , Lithium perchlorate), LiCl, LiBr, LiI, LiClO 4 , LiB 10 Cl 10 , LiAlCl 4 , LiSCN, LiC 4 BO 8 , LiCH 3 SO 3 , lithium chloroborane, lithium lower aliphatic carboxylic acid, lithium 4-phenylborate imide, or a combination thereof The non-fluorine-based secondary battery according to claim 7.

9. The aforementioned non-aqueous solution is vinylene carbonate, propylene sulfone, lithium bisoxalate borate. bisoxalatoborate (LiBOB), N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfuran (franc), 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, ethyl propionate, or combinations thereof. A non-fluorine-based secondary battery according to claim 1.

10. It comprises a diamine monomer unit containing a sulfone, a diamine monomer unit containing a carboxylic acid, and a monomer unit containing at least one aromatic ring. It is a binder for the positive electrode, a binder for the negative electrode, a binder for the separation membrane, or a binder for coating a plain area. Non-fluorinated polyamide polymer.

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