polymer layer

Abstract

This specification discloses a polymer layer, a method for manufacturing the same, and its applications. The polymer layer exhibits a so-called PTC (Positive Temperature Coefficient) effect at the required level when needed, and can be applied as a material that can ensure stability in applications where stability under abnormally high temperatures or flames is a concern. The polymer layer exhibits oxidation potential characteristics suitable for the application, and can stably maintain such oxidation potential characteristics even under harsh environments. The polymer layer can rapidly exhibit the PTC effect at the required level when needed. The polymer layer has a flat surface and excellent resistance to scratches and the like. This specification discloses a method for manufacturing the polymer layer and its applications.

Description

[Technical Field]

[0001] This application claims priority rights based on Korean Patent Applications No. 10-2023-0108457, No. 10-2023-0108421 dated August 18, 2023, and Korean Patent Application No. 10-2023-0115816 dated August 31, 2023, and the contents of the documents of said patent applications are included as part of this specification.

[0002] This specification discloses polymer layers, methods for producing the same, and applications thereof. [Background technology]

[0003] Energy storage technology is seeing expanding applications in a wide range of devices, from mobile phones and tablets to laptops and even electric vehicles.

[0004] In mobile devices such as cell phones and tablets, the development of secondary batteries with high energy density, high operating potential, long cycle life, and low self-discharge rate is progressing in response to improvements in data processing speed and extensions in usage time.

[0005] In line with the trend among major developed countries to curb the production of internal combustion engine-driven vehicles in order to combat global warming and air pollution, major automakers are also developing various electric vehicles, and the importance of secondary batteries with high energy density, high discharge voltage, and output stability as their power source is increasing even further.

[0006] Along with this trend, the frequency of fires and explosions in devices and automobiles that use secondary batteries as an energy source, caused by overcharging, high-temperature exposure, or external impacts, is also increasing.

[0007] The main cause of such accidents is known to be a short circuit, where the positive and negative electrodes inside the electrode assembly come into direct contact due to external stimuli. When a secondary battery is overcharged, exposed to high temperatures, or subjected to external stimuli, the aforementioned short circuit may occur due to the contraction of the separator caused by the rise in internal temperature of the secondary battery, or damage to the internal structure of the secondary battery due to external impact.

[0008] When a short circuit occurs, the movement of lithium ions and electrons concentrates through the area where the positive and negative electrodes are in direct contact, which can accelerate internal heat generation. As a result, gases and other substances are generated inside the battery, causing it to expand in volume and increasing the risk of fire. [Overview of the project] [Problems that the invention aims to solve]

[0009] This specification discloses polymer layers, methods for manufacturing the same, and applications thereof. The objective of this specification is to disclose a polymer layer that can be applied as a material that can ensure stability in applications where stability due to abnormally high heat or flame is a problem, by exhibiting the so-called PTC (Positive Temperature Coefficient) effect at the required time and level. Another objective of this specification is to disclose a polymer layer that exhibits oxidation potential properties suitable for the application and in which such oxidation potential properties are stably maintained even under harsh environments. Another objective of this specification is to disclose a polymer layer in which the PTC effect is rapidly exhibited at the required time and level. Another objective of this specification is to disclose a polymer layer having a flat surface and excellent resistance to scratches, etc. Another objective of this specification is to disclose a method for manufacturing the polymer layer and applications thereof. [Means for solving the problem]

[0010] In this specification, the term "room temperature" means the natural temperature that has not been artificially heated or cooled. Room temperature may be, for example, any temperature within the range of 10°C to 30°C, or a temperature of about 23°C, 25°C, or 27°C.

[0011] Of the physical properties mentioned herein, those affected by measurement temperature are those measured at room temperature unless otherwise specified.

[0012] In this specification, the unit of temperature is Celsius (°C) unless otherwise specified.

[0013] In this specification, the term "atmospheric pressure" means the natural pressure that has not been artificially pressurized or depressurized, and typically refers to a pressure in the range of approximately 730 mmHg to 790 mmHg.

[0014] Of the physical properties mentioned herein, those affected by measurement pressure are those measured at normal pressure unless otherwise specified.

[0015] In this specification, standard humidity refers to any relative humidity within the range of 40% to 60%. For example, relative humidity of approximately 40%, 45%, 50%, 55%, or 60% can be considered standard humidity.

[0016] Of the physical properties mentioned herein, those affected by the measured humidity are those measured at the standard humidity conditions unless otherwise specified.

[0017] In this specification, the term "normal state" means the normal operating state (e.g., the normal charging and discharging state of a secondary battery) and / or storage state of electrical and electronic equipment such as secondary batteries.

[0018] In this specification, the term "abnormal condition" means a state in which abnormal heat generation, ignition, and / or explosion occur in electrical and electronic equipment such as secondary batteries, or a state in which the risk of such abnormal heat generation, ignition, and / or explosion increases. For example, an abnormal condition is a dangerous state in which abnormal heat generation, ignition, or explosion occurs in a secondary battery due to a short circuit or the like, or in which the possibility of such heat generation, ignition, or explosion increases.

[0019] This specification discloses a polymer layer.

[0020] The term "polymer layer" means a layer containing a polymer. The lower limit of the polymer content in the polymer layer may be approximately 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight, or 95% by weight, and the upper limit may be approximately 100% by weight, 95% by weight, 90% by weight, 85% by weight, 80% by weight, 75% by weight, 70% by weight, 65% by weight, 60% by weight, 55% by weight, or 50% by weight. The content is the polymer content relative to the total amount of the polymer layer. The content may be within the range of being greater than or exceeding any one of the lower limits selected from the listed lower limits, or less than or equal to any one of the upper limits selected from the listed upper limits, and within the range of being greater than or exceeding any one of the lower limits selected from the listed lower limits.

[0021] The polymer layer does not have to be a so-called electrode active material layer. The content of the electrode active material in the polymer layer may be controlled. For example, the upper limit of the content of the electrode active material in the polymer layer may be around 10% by weight, 9% by weight, 8% by weight, 7% by weight, 6% by weight, 5% by weight, 4% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, 0.1% by weight, 0.05% by weight, 0.01% by weight, 0.005% by weight, or 0.001% by weight, and the lower limit may be 0% by weight. The content is the content of the electrode active material based on the total amount of the polymer layer. The content may be within a range of less than or equal to any one of the upper limits selected from the listed upper limits, or within a range of less than or equal to any one of the upper limits selected from the listed upper limits, and greater than or equal to the lower limit.

[0022] The polymer layer may contain a conductive polymer. A conductive polymer is, as is well known, a polymer that exhibits conductivity through a conjugated system of polymer chains and / or doping. For example, the conductive polymer may be a polymer that exhibits low resistance in a doped state and high resistance in a de-doped state, and is designed so that the transition between these doped and de-doped states occurs rapidly at the necessary time depending on the temperature and / or voltage.

[0023] Depending on the application, the polymer layer may need to exhibit an appropriate level of oxidation potential. For example, when the polymer layer is located between the current collector body and the active material layer, as described later, the polymer layer needs to exhibit a lower oxidation potential than the active material layer, and this low oxidation potential must be maintained even during repeated charging and discharging and / or high-speed charging and discharging of the secondary battery. Otherwise, a potential drop phenomenon may occur during the process of repeated charging and discharging and / or high-speed charging and discharging.

[0024] For example, the polymer layer can adjust the absolute value of ΔV in the following formula 1.

[0025] [Formula 1] ΔV = 100×(V V i ) / V i

[0026] V in Formula 1 i is the oxidation potential of the polymer layer after one injection of cyclic voltammetry. The cyclic voltammetry injection can be performed at a scan rate of 0.83 mV / second in the range of 3V to 4.5V, and the oxidation potential is the Li / Li + reference oxidation potential.

[0027] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The upper limit of the absolute value of △V may be approximately 3%, 2.9%, 2.8%, 2.7%, 2.6%, 2.5%, 2.4%, 2.3%, 2.2%, 2.1%, 2.0%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, 0.7%, or 0.6%, and its lower limit may be approximately 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%. The aforementioned △V may be within the range of either the upper limit selected from the enumerated upper limits or less than or equal to the lower limit selected from the enumerated lower limits, and within the range of either the upper limit selected from the enumerated upper limits or less than or equal to the upper limit of either the enumerated upper limits.

[0032] The aforementioned △V may be a positive or negative value.

[0033] The lower the value of ΔV, the more stably the polymer layer maintains a low oxidation potential.

[0034] The oxidation potential of the polymer layer can be adjusted to an appropriate level. At this time, the oxidation potential is V in Equation 1. i It is similar to that.

[0035] The upper limit of the oxidation potential of the polymer layer may be approximately 4.0V, 3.95V, 3.9V, 3.85V, 3.8V, 3.75V, 3.7V, 3.65V, 3.6V, 3.55V, 3.5V, 3.45V, or 3.4V, and the lower limit may be approximately 1V, 1.5V, 2V, 2.5V, 3V, 3.1V, 3.2V, 3.3V, or 3.4V. The oxidation potential may be within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or greater than or greater than one of the lower limits selected from the enumerated lower limits, and within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits.

[0036] As described above, the conductive polymer contained in the polymer layer is a polymer that exhibits different electrical resistances in a doped state and a de-doped state, and may be a polymer in which the transition between the doped state and the de-doped state occurs rapidly when necessary.

[0037] For example, the polymer layer can adjust Q in the following formula 2.

[0038] [Formula 2] Q=R 3V / R 3.3V

[0039] R in Equation 2 3V This is the AC impedance resistance of the polymer layer under external voltage conditions of 25°C and 3V.

[0040] R in Equation 2 3.3V This is the AC impedance resistance of the polymer layer after 1 second has elapsed since the external voltage was converted to 3.3V, for a polymer layer that had been exposed to the aforementioned external voltage conditions of 25°C and 3V.

[0041] Resistor R in Equation 2 3V and R 3.3V These two units have the same unit, for example, their unit is Ω.

[0042] Resistor R in Equation 2 3V and R 3.3V This can be confirmed in the coin cell to which the polymer layer is applied. The resistance R in Equation 2 above 3V and R 3.3V This can be verified according to the method described in the Examples section of this specification, "AC Impedance Resistance at 5.3V and 3.3V".

[0043] The lower limit of the Q value may be approximately 10, 50, 70, 80, 90, 100, 110, 120, 130, or 140, and its upper limit may be approximately 400, 350, 300, 250, 200, 150, or 100. The Q value may be within the range of either the lower limit selected from the listed lower limits or greater than or greater than the lower limit selected from the listed lower limits, and less than or equal to the upper limit selected from the listed upper limits.

[0044] A higher Q value in Equation 2 means that the resistance of the polymer layer decreases more rapidly when the external voltage conditions are changed (from 3V to 3.3V).

[0045] AC impedance resistor R in Equation 2 3.3V The upper limit may be around 5000, 4500, 4000, 3500, 3000, 2500, 2000, 1500, 1000, 900, 800, 700, 600, 500, 400, 350, 300, or 250, and the lower limit may be, for example, around 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, or 400. 3.3V The unit is Ω. 3.3V It may be within the range of either the lower limit selected from the listed lower limits or exceeding it, or within the range of either the upper limit selected from the listed upper limits or less than it, or within the range of either the lower limit selected from the listed lower limits or exceeding it, and either the upper limit selected from the listed upper limits or less than it.

[0046] The polymer layer can exhibit a high PTC effect.

[0047] For example, the polymer layer can be designed such that P in the following formula 3 falls within a predetermined range.

[0048] [Formula 3] P=R 130 / R 25

[0049] In Equation 3, R 130 R is the AC impedance resistance of the polymer layer at 130°C, 25 This is the AC impedance resistance of the polymer layer at 25°C.

[0050] R in Equation 3 130 and R 25 These two units have the same unit, for example, their unit is Ω.

[0051] AC impedance resistor R 130 and R 25 This is the resistance observed in the coin cell to which the polymer layer is applied, and the method for measuring it is described in section 6, "AC Impedance Resistance at Room Temperature (25°C) and 130°C," of the Examples section of this specification.

[0052] The lower limit of P in Equation 3 may be around 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,100, 1,200, 1,300, 1,400, or 1,450, and its upper limit may be around 10,000, 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3,000, 2,000, 1,500, 1,400, 1,300, 1,200, 1,100, 1,000, 950, 900, or 850. In Equation 3, P may be within the range of either or greater than one of the lower limits selected from the listed lower limits, or it may be within the range of either or less than one of the upper limits selected from the listed upper limits, while being both greater than or greater than one of the lower limits selected from the listed lower limits.

[0053] The polymer layer exhibits the aforementioned P value while showing low resistance at room temperature (approximately 25°C).

[0054] For example, the resistance R of the AC impedance in Equation 3 25 The upper limit may be around 500, 450, 400, 350, 300, 250, 200, 150, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 28, 26, 24, or 22, and the lower limit may be, for example, around 10, 15, 20, 25, 30, 35, or 40. 25 The unit is Ω. 25 It may be within the range of either the upper limit selected from the listed upper limits, or greater than or greater than the lower limit selected from the listed lower limits, and within the range of either the upper limit selected from the listed upper limits.

[0055] The polymer layer may have a flat surface. For example, the upper limit of the arithmetic mean roughness Ra of the surface of the polymer layer may be around 200, 190, 180, 170, 160, 150, or 145, and the lower limit may be around 10, 50, 100, 120, 140, or 160. The unit of Ra is nm. Ra may be within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or greater than or greater than one of the lower limits selected from the enumerated lower limits, and within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits. The lower the Ra, the better resistance to scratches and the like can be ensured. Ra can be measured by the method described in "8. Arithmetic Mean Roughness Ra" of the Examples section of this specification.

[0056] In other examples, the upper limit of the ratio Ra / T of the arithmetic mean roughness of the polymer layer to its thickness T may be approximately 0.5, 0.45, 0.4, or 0.35, and the lower limit may be approximately 0, 0.5, 1, 1.5, 2, 2.5, 3, or 3.5. The Ra / T may be within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or greater than or greater than one of the lower limits selected from the enumerated lower limits, and within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits. A lower Ra / T ensures better resistance to scratches and the like. The Ra can be measured by the method described in "8. Arithmetic Mean Roughness Ra" of the Examples section of this specification, and the thickness T can be measured by the method described in "3. Thickness Measurement" of the Examples section of this specification. The units of Ra and T are nm, respectively.

[0057] In the above, the thickness T of the polymer layer can be appropriately controlled depending on the purpose. For example, the lower limit of the thickness T of the polymer layer may be around 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, or 400 nm, and the upper limit may be around 2 μm, 1.5 μm, 1 μm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, 600 nm, 550 nm, 500 nm, 450 nm, or 400 nm. The thickness may be greater than or greater than one of the lower limits selected from the listed lower limits, and less than or equal to one of the upper limits selected from the listed upper limits.

[0058] The conductive polymer contained in the polymer layer may be a thiophene polymer.

[0059] The term thiophene polymer refers to a polymer that contains a certain level or more of thiophene monomer units.

[0060] For example, the lower limit of the ratio of moles of thiophene monomer units in the thiophene polymer may be around 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, or 80 mol%, and the upper limit may be around 100 mol%, 95 mol%, 90 mol%, or 80 mol%. The ratio of moles of thiophene monomer units is the number of moles of all thiophene monomer units present in the thiophene polymer (M) relative to the total number of moles of monomer units present in the thiophene polymer (M) or the total number of moles of monomers applied to produce the thiophene polymer (M). T ) or the number of moles (M) of all thiophene monomers applied to produce the thiophene polymer. T ) ratio (100 × M T The ratio of the thiophene monomer units is ((100 × M). T / M) may be within the range of either the lower limit selected from the listed lower limits or exceeding it, or it may be either the lower limit selected from the listed lower limits or exceeding it, and within the range of either the upper limit selected from the listed upper limits or less.

[0061] The term monomer unit refers to a form in which a monomer polymerizes and is included in a polymer. The term thiophene monomer refers to a thiophene-based monomer, meaning a monomer that contains a thiophene skeleton.

[0062] The conductive polymer may contain long-chain hydrocarbon functional groups or monomer units having such long-chain hydrocarbon functional groups (hereinafter referred to as unit A). Unit A may be a thiophene monomer unit.

[0063] The term "long-chain hydrocarbon functional group" refers to a monovalent hydrocarbon group with a certain number of carbon atoms or a monovalent functional group containing such monovalent hydrocarbon group.

[0064] For example, the lower limit of the number of carbon atoms present in the long-chain hydrocarbon functional group (i.e., the number of carbon atoms in the monovalent hydrocarbon group) may be approximately 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, and the upper limit may be approximately 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, or 4. The number of carbon atoms may be within the range of either the lower limit or greater than one of the lower limits selected from the listed lower limits, or less than or equal to one of the upper limits selected from the listed upper limits, and within the range of either the lower limit or greater than one of the lower limits selected from the listed lower limits.

[0065] The carbon number may be the total number of carbon atoms present in the long-chain hydrocarbon functional group, or it may be the number of carbon atoms in the straight-chain hydrocarbon chain of the functional group. That is, the monovalent hydrocarbon group present in the long-chain hydrocarbon functional group may have a straight-chain or branched-chain structure. If the monovalent hydrocarbon group has a straight-chain structure, the number of carbon atoms in the straight-chain structure may be within the range described above. If the monovalent hydrocarbon group has a branched-chain structure, the number of carbon atoms constituting the longest straight chain in the branched-chain structure may be within the range described above. For example, if the branched-chain structure is a 2-ethylhexyl group, the number of carbon atoms constituting the longest straight chain is 6.

[0066] Examples of the long-chain hydrocarbon functional group include one or more selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylcarbonyl groups, and alkylcarbonyloxy groups. Preferably, the long-chain hydrocarbon functional group may be an alkyl group and / or an alkoxy group.

[0067] The number of carbon atoms present in the alkyl group, alkenyl group, alkynyl group, alkoxy group, alkylcarbonyl group, and alkylcarbonyloxy group may be within the range of the number of carbon atoms present in the long-chain hydrocarbon functional group (i.e., the number of carbon atoms in the monovalent hydrocarbon group).

[0068] The alkyl group, alkenyl group, alkynyl group, alkoxy group, alkyl group of alkylcarbonyl group, and alkyl group of alkylcarbonyloxy group may be linear or branched. If it is branched, the number of carbon atoms constituting the longest linear chain in the branched chain structure may be within the range described above.

[0069] The aforementioned long-chain hydrocarbon functional group, which is an alkyl group, alkenyl group, alkynyl group, alkoxy group, alkylcarbonyl group, or alkylcarbonyloxy, may be substituted with one or more substituents.

[0070] Long-chain hydrocarbon functional groups can exhibit enhanced vibrational energy at increased temperatures. This enhanced vibrational energy can influence the doping and dedoping state of conductive polymers. The degree of the vibrational energy and the temperature at which it appears are influenced by the number of carbon atoms and the arrangement of the long-chain hydrocarbon functional groups. Therefore, by adjusting the number and amount of carbon atoms of the long-chain hydrocarbon functional groups and adjusting their arrangement using the manufacturing method described later, the properties of the polymer layer (for example, ΔV, V in formula 1) can be improved. f and V i Q and R in Equation 2 3V and R 3.3V R in Equation 3 130 and R 25 For example, at the same temperature, the vibrational energy of relatively long chains is greater than that of relatively short chains. Therefore, by appropriately employing long-chain and short-chain hydrocarbon functional groups, it is possible to provide conductive polymers that meet the desired effects.

[0071] Furthermore, the long-chain hydrocarbon functional groups can impart appropriate fluidity (mobility) to the monomer or polymer during the polymerization process of the conductive polymer, thereby improving polymerization efficiency.

[0072] For example, the number of moles of the long-chain hydrocarbon functional group (M) relative to the total number of monomer units (M) of the conductive polymer. L ) or the number of moles (M) of monomer units (unit A) having the functional group. L The ratio of (M) can be adjusted. For example, the lower limit of the ratio may be around 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, or 70 mol%, and the upper limit may be around 95 mol%, 90 mol%, 85 mol%, 80 mol%, or 75 mol%. The ratio is the number of moles of all long-chain hydrocarbon functional groups (M) present in the conductive polymer relative to the number of moles of all monomer units (M) present in the conductive polymer or the number of moles of all monomers (M) applied to produce the conductive polymer. L ) or the branching of the long-chain hydrocarbon functional group is determined by the number of moles (M) of monomer units. L ) or all branching of long-chain hydrocarbon functional groups applied to produce the thiophene polymer is the number of moles (M) of monomers L ) ratio (100 × M L The ratio is / M). The ratio is within the range of either the lower limit selected from the listed lower limits or greater than or greater than the upper limit selected from the listed upper limits, and may be within the range of either the lower limit selected from the listed lower limits or greater than or greater than the lower limit selected from the listed lower limits.

[0073] The conductive polymer may contain a first hydrocarbon functional group and a second hydrocarbon functional group.

[0074] The first hydrocarbon functional group is a functional group with a relatively large number of carbon atoms among the long-chain hydrocarbon functional groups. The lower limit of the number of carbon atoms of such a first hydrocarbon functional group may be around 10, 11, or 12, and the upper limit may be around 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10. The number of carbon atoms of the first hydrocarbon functional group may be within the range of being greater than or exceeding one of the lower limits selected from the listed lower limits, or less than or equal to one of the upper limits selected from the listed upper limits, and within the range of being greater than or exceeding one of the lower limits selected from the listed lower limits.

[0075] The second hydrocarbon functional group is a functional group with a relatively small number of carbon atoms among the long-chain hydrocarbon functional groups. The lower limit of the number of carbon atoms of such a second hydrocarbon functional group may be around 3, 4, 5, 6, 7, or 8, and the upper limit may be around 9, 8, 7, or 6. The number of carbon atoms of the second hydrocarbon functional group may be within the range of either the upper limit selected from the listed upper limits, or within the range of either the upper limit selected from the listed upper limits and either the lower limit selected from the listed lower limits or greater than.

[0076] The number of carbon atoms in each of the first and second hydrocarbon functional groups may be the number of carbon atoms in the linear hydrocarbon chain present in the hydrocarbon functional group. For example, each of the first and second hydrocarbon functional groups may independently be one or more selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylcarbonyl groups, and alkylcarbonyloxy groups, preferably alkyl groups and / or alkoxy groups, and the number of carbon atoms may be the number of carbon atoms in the alkyl group, alkenyl group, alkynyl group, alkoxy group, alkyl group of alkylcarbonyl group, and alkyl group of alkylcarbonyloxy group.

[0077] The alkyl group, alkenyl group, alkynyl group, alkoxy group, alkyl group of alkylcarbonyl group, and alkyl group of alkylcarbonyloxy group may be linear or branched in structure. If linear, the total number of carbon atoms may be within the range described above. If branched, the number of carbon atoms constituting the longest linear chain in the branched structure may be within the range described above.

[0078] As described above, the carbon number of the long-chain hydrocarbon functional group indicates a functional group that exhibits enhanced vibrational energy at increased temperatures, meaning that a higher carbon number at the same temperature results in higher vibrational energy. In other words, the first hydrocarbon functional group exhibits higher vibrational energy than the second hydrocarbon functional group at the same temperature, and the sum of the vibrational energies of these two types of functional groups allows for the optimization of the properties of conductive polymers, which are difficult to precisely control with a single functional group.

[0079] For example, the first hydrocarbon functional group exhibits enhanced vibrational energy at increased temperatures, and the second hydrocarbon functional group dilutes the vibrational energy of the first hydrocarbon functional group at the same temperature, thereby allowing for precise control of the onset point of dedoping of the conductive polymer as desired.

[0080] The ratio of the total number of moles of the first and second hydrocarbon functional groups to the total number of moles (M) of monomer units of the conductive polymer, or the ratio of the total number of moles of monomer units having the first hydrocarbon functional group to the total number of moles of monomer units having the second hydrocarbon functional group, is 100 × M. L It can be adjusted within the same range as / M.

[0081] The lower limit of the ratio (M2 / M1) of the number of moles of the second hydrocarbon functional group (M2) or the number of moles of monomer units having the second hydrocarbon functional group (M2) to the number of moles of the first hydrocarbon functional group (M1) or the number of moles of monomer units having the first hydrocarbon functional group (M1) may be around 0.01, 0.05, 0.1, or 0.5, and the upper limit may be around 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 9, 7, 6, 5, 4, 3, 2, 1, or 0.7. The ratio may be less than or equal to one of the upper limits selected from the listed upper limits, and greater than or equal to one of the lower limits selected from the listed lower limits. The ratio M2 / M1 can be changed considering the target vibration energy level and the design value of the polymer layer.

[0082] The conductive polymer may contain polar functional groups along with the long-chain hydrocarbon functional groups. The monomer having the polar functional group may be a thiophene monomer.

[0083] The term "polar functional group" refers to a functional group that contains one or more polar atoms, such as oxygen and / or nitrogen. Examples of such functional groups include, but are not limited to, carboxyl groups, hydroxyl groups, amino groups, cyano groups, nitro groups, ether groups, alkoxy groups, and / or the functional group of formula 1 below.

[0084] The alkoxy group may, for example, be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy group may be linear, branched, or cyclic, and preferably linear or branched. The alkoxy group may be substituted with one or more substituents.

[0085] As an example, the functional group shown in Chemical Formula 1 below can be used as the polar functional group.

[0086] [ka]

[0087] In chemical formula 1, L1 is a single bond, an alkylene group, or an alkylidene group; L2 is an alkylene group or an alkylidene group; R1 is a hydrogen atom or an alkyl group; and m is any number.

[0088] In chemical formula 1, L1 being a single bond means that L1 does not exist, and the oxygen atom between L1 and L2 is directly connected to the monomer.

[0089] The alkyl group R1 in Chemical Formula 1 may, for example, be an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, and may be a methyl group or an ethyl group. The alkyl group may be linear, branched, or cyclic, and is preferably linear or branched. The alkyl group may be substituted with one or more substituents.

[0090] The term alkylene group refers to a divalent functional group formed by the elimination of one hydrogen atom from each of two different carbon atoms in an alkane, while the term alkylidene group refers to a divalent functional group formed by the elimination of two hydrogen atoms from one carbon atom in an alkane.

[0091] The alkylene groups L1 and L2 in Chemical Formula 1 may, for example, be alkylene groups having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, and may also be ethylene or propylene groups. The alkylene groups may be linear, branched, or cyclic, and are preferably linear or branched. The alkylene groups may be substituted with one or more substituents.

[0092] The alkylidene groups L1 and L2 in Chemical Formula 1 may, for example, be alkylidene groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, and may also be methyllidene, ethylidene, or propylidene groups. The alkylidene groups may be linear, branched, or cyclic, and are preferably linear or branched. The alkylidene groups may be substituted with one or more substituents.

[0093] In chemical formula 1, the lower limit of m may be 1, 2, 3, or 4, and its upper limit may be approximately 10, 9, 8, 7, 6, 5, 4, or 3. The aforementioned m may be less than or equal to any one of the upper limits selected from the enumerated upper limits, and greater than or equal to any one of the lower limits selected from the enumerated lower limits.

[0094] The polar functional groups can bond the polymer layer to other layers with appropriate bonding force, and when combined with the long-chain hydrocarbon functional groups, they can significantly improve the dispersibility of the conductive material within the polymer layer, as described later. Furthermore, the polar functional groups can also play a role in suppressing the PTC effect at relatively low temperatures.

[0095] The number of moles of polar functional groups and long-chain hydrocarbon functional groups in the conductive polymer can be controlled to ensure the appropriate effect.

[0096] For example, the number of moles (M) of the long-chain hydrocarbon functional groups in the conductive polymer. L ) or the number of moles of monomer units having the long-chain hydrocarbon functional group (M L ) and the number of moles of the polar functional group (M P ) or the number of moles (M) of monomer units having the polar functional group. P ) ratio (M L / M PThe lower limit of ) may be around 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, or 9, and the upper limit may be around 500, 450, 400, 350, 300, 250, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, or 9.5. The ratio M L / M P It may be within the range of either the upper limit selected from the enumerated upper limits or less, or within the range of either the lower limit selected from the enumerated lower limits or more, or within the range of either the upper limit selected from the enumerated upper limits and either the lower limit selected from the lower limits or more. In the above, ratio M L / M P If this is a ratio between monomer units, then the ratio is the number of moles M of all long-chain hydrocarbon functional group monomer units present in the conductive polymer. L and the number of moles M of monomer units having all polar functional groups P The ratio of M of all long-chain hydrocarbon functional groups applied to produce the conductive polymer. L and the number of moles M of monomers having all polar functional groups P The ratio may also be acceptable.

[0097] The total number of moles M of monomer units having long-chain hydrocarbon functional groups and monomer units having polar functional groups relative to the total number of moles M of all monomer units in the conductive polymer. S The ratio is the aforementioned ratio 100 × M T It can be adjusted within the same range as / M. In this case, the number of moles M T Instead, the number of moles M S This is substituted.

[0098] For example, the conductive polymer may include the unit of the following chemical formula 2 as the thiophene monomer unit.

[0099] [ka]

[0100] In chemical formula 2, R2 and R3 may each independently be hydrogen, the polar functional group, or the long-chain hydrocarbon functional group. In other examples, R2 and R3 in formula 2 may be linked together to form the divalent functional group of chemical formula 3 below.

[0101] [ka]

[0102] In chemical formula 3, L3 and L4 may each be independently a single bond, an alkylene group, or an alkylidene group, and R4 and R5 may each be independently hydrogen, the polar functional group, or the long-chain hydrocarbon functional group.

[0103] In chemical formula 2, if R2 and R3 are independently hydrogen, a polar functional group, or a long-chain hydrocarbon functional group, then at least one of R2 and R3 may be the polar functional group or the long-chain hydrocarbon functional group.

[0104] In chemical formula 2, if R2 and R3 form the divalent functional group of chemical formula 3, at least one of R4 and R5 may be the polar functional group or the long-chain hydrocarbon functional group.

[0105] In chemical formula 3, the meanings and specific examples of the single bond, alkylene group, and alkylidene group are the same as in chemical formula 1. In chemical formulas 2 and 3, the technical significance and specific examples of the long-chain hydrocarbon functional group and polar functional group are as described above.

[0106] The number of moles of the unit of chemical formula 2 relative to the total number of moles of monomer units of the conductive polymer (M) C2 The ratio is the aforementioned ratio 100 × M T It can be adjusted in the same way as / M, and at this time M T M C2It can be replaced with this.

[0107] In one example, the conductive polymer may contain monomer units represented by the following chemical formula 4. The monomer unit of chemical formula 4 may be an example of a monomer unit having the first hydrocarbon functional group.

[0108] [ka]

[0109] In chemical formula 4, R6 and R7 may each be independently hydrogen or the first hydrocarbon functional group. In such cases, one or more of R6 and R7 may be the first hydrocarbon functional group.

[0110] In other examples, R6 and R7 can be linked together to form a divalent functional group of the following chemical formula 5.

[0111] [ka]

[0112] In chemical formula 5, L5 and L6 are each independently a single bond, an alkylene group, or an alkylidene group, and R8 and R9 are each independently hydrogen or the first hydrocarbon functional group, although one or more of R8 and R9 may be the first hydrocarbon functional group.

[0113] The specific details of the first hydrocarbon functional group are as described above, and the specific details of the single bond, alkylene group, or alkylidene group are as described in Formula 1.

[0114] The conductive polymer may further contain monomer units represented by the following chemical formula 6. The monomer units of chemical formula 6 may be examples of monomer units having the second hydrocarbon functional group.

[0115] [ka]

[0116] In chemical formula 6, R 10 and R 11 Each of these may independently be hydrogen or the second hydrocarbon functional group, in which case R 10 and R 11 One or more of these may be the second hydrocarbon functional group.

[0117] In other examples, R 10 and R 11 These can link together to form a divalent functional group of the chemical formula 7 shown below.

[0118] [ka]

[0119] In chemical formula 7, L7 and L8 are independently a single bond, an alkylene group, or an alkylidene group, and R 12 and R 13 Each is independently either hydrogen or the second hydrocarbon functional group, and R 12 and R 13 One or more of these are the second hydrocarbon functional groups.

[0120] The specific details of the second hydrocarbon functional group are as described above, and the specific details of the single bond, alkylene group, and alkylidene group are as shown in Chemical Formula 1.

[0121] The conductive polymer may further contain monomer units represented by the following chemical formula 8. The monomer units of chemical formula 8 may be examples of monomer units having the polar functional group.

[0122] [ka]

[0123] In chemical formula 8, R14 and R 15 may each independently be hydrogen or the polar functional group. In this case, one or more of said R 14 and R 15 are the polar functional group.

[0124] In other examples, R 14 and R 15 in Chemical Formula 8 above may be linked to each other to form a divalent functional group of Chemical Formula 9 below.

[0125]

Chemical Formula

[0126] In Formula 9, L9 and L 10 are each independently a single bond, an alkylene group or an alkylidene group, and R 16 and R 17 are each independently hydrogen or a polar functional group, and one or more of R 16 and R 17 are the polar functional group.

[0127] The specific details of the polar functional group are as described above, and the specific details of the single bond, alkylene group and alkylidene group are as described in Chemical Formula 1.

[0128] When the conductive polymer contains the monomer unit of Chemical Formula 4 and the monomer unit of Chemical Formula 6 simultaneously, the ratio of the total number of moles M 4+6 of the monomer unit of Chemical Formula 4 and the monomer unit of Chemical Formula 6 to the total number of moles M of all monomer units contained in the conductive polymer can be adjusted within the same range as the ratio 100×M L / M, and at this time ML is replaced by M 4+6 .

[0129] The ratio of the number of moles M4 of the monomer units of chemical formula 4 to the number of moles M6 of the monomer units of chemical formula 6 can be adjusted within the same range as the ratio M2 / M1. In this case, the number of moles M1 can be the number of moles of the monomer units of chemical formula 4, and the number of moles M2 can be the number of moles of the monomer units of chemical formula 6.

[0130] When the conductive polymer contains monomer units of the chemical formula 8, the units are in molar ratio M L / M P It can be included such that the following conditions are met. In this case, the number of moles of the monomer units of chemical formula 8 is the number of moles M. P This is the result. Also, the number of moles M L This may be the number of moles of the monomer units of chemical formula 4, the number of moles of the monomer units of chemical formula 6, or the total number of moles of the monomer units of chemical formula 4 and the monomer units of chemical formula 6.

[0131] When monomer units of chemical formulas 4, 6, and 8 are present in a conductive polymer, the total number of moles of monomer units of chemical formulas 4, 6, and 8 is M. 4+6+8 The ratio of the number of monomer units in the conductive polymer to the total number of moles M is the ratio 100 × M T It can be adjusted within the same range as / M. In this case, the number of moles M 4+6+8 The number of moles is M T This is the result.

[0132] The conductive polymer may contain the monomer units and may further contain other monomer units. For example, the conductive polymer may contain bithiophene monomer units in addition to the thiophene monomer units.

[0133] The bithiophene monomer unit is a monomer unit other than a thiophene monomer, and is a unit for adjusting the oxidation potential of the conductive polymer. For example, the bithiophene monomer unit may be a monomer unit that can copolymerize with a thiophene monomer and exhibits a lower oxidation potential than polythiophene when produced as a homopolymer.

[0134] In the above case, the molar ratio of the thiophene monomer units in the conductive polymer is the ratio 100 × M T It can be adjusted within the same range as / M. Furthermore, the ratio of the bithiophene monomer units can be adjusted considering the desired oxidation potential.

[0135] For example, the lower limit of the number of moles of bithiophene monomer units per mole of thiophene monomer units in the conductive polymer may be approximately 0.05 moles, 0.1 moles, 0.15 moles, 0.2 moles, 0.22 moles, or 0.24 moles, and the upper limit may be approximately 1 mole, 0.9 moles, 0.8 moles, 0.7 moles, 0.6 moles, 0.5 moles, 0.4 moles, or 0.3 moles. The ratio may be within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or within the range of either the lower limit or more than one of the lower limits selected from the enumerated lower limits, or within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, and either the lower limit or more than one of the lower limits selected from the enumerated lower limits.

[0136] The bithiophene monomer unit may be, for example, an aromatic monomer unit or a nitrogen-containing heterocyclic monomer unit. The aromatic monomer unit is a unit formed from an aromatic monomer unit, and the nitrogen-containing heterocyclic monomer unit is a unit formed from a nitrogen-containing heterocyclic monomer.

[0137] For example, the bithiophene monomer unit may be the monomer unit of the following chemical formula 10.

[0138] [ka]

[0139] In chemical formula 10, R 18 , R 19 and R 20Each of these may independently be hydrogen, the polar functional group, or the hydrocarbon functional group.

[0140] Examples of the hydrocarbon functional groups mentioned above include alkyl groups, alkenyl groups, or aryl groups.

[0141] Each of the alkyl groups may independently be alkyl groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

[0142] The aforementioned alkenyl group may be an alkenyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms.

[0143] The aryl group may be, for example, an aryl group having 6 to 30 carbon atoms, or 6 to 26 carbon atoms, or 6 to 22 carbon atoms, or 6 to 20 carbon atoms, or 6 to 18 carbon atoms, or 6 to 15 carbon atoms.

[0144] The alkyl group and alkenyl group may each be independently linear, branched, or cyclic. The alkyl group, alkenyl group, and aryl group may each be independently substituted with one or more substituents.

[0145] The specific details of the polar functional group are as described above. For example, the unit of chemical formula 10 may be a polypyrrole unit.

[0146] In other examples, the bithiophene monomer unit may be the unit of the following chemical formula 11.

[0147] [ka]

[0148] In chemical formula 11, L 11 These are single bonds, alkylene groups, alkylidene groups, O or NR 1It may also be the case. In the above, the meanings of single bond, alkylene group, or alkylidene group are as shown in Chemical Formula 1. Also, the above R 1 This may be hydrogen, an alkyl group, an alkenyl group, or an aryl group.

[0149] In chemical formula 11, R 21 ~R 24 Each of these may independently be a hydrogen atom, an alkyl group, an alkenyl group, an amino group, an alkoxy group, an aryl group, or a halogen atom.

[0150] The specific types of alkyl groups, alkenyl groups, and aryl groups in chemical formula 11 are as shown in chemical formula 10.

[0151] The alkoxy group of chemical formula 11 may be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Each of the alkoxy groups may independently be linear, branched, or cyclic. The alkoxy group may be substituted with one or more substituents.

[0152] For example, the monomer unit of chemical formula 11 may be a polyaniline or polyphenylene monomer unit.

[0153] In other examples, the bithiophene monomer unit may be the unit of the following chemical formula 12.

[0154] [ka]

[0155] In chemical formula 12, X1 is S, O, or NR 1 It may also be R 1 This may be hydrogen, an alkyl group, an alkenyl group, or an aryl group.

[0156] In chemical formula 12, R 25~R 28 Each of these may independently be hydrogen, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, or a halogen.

[0157] The specific types of alkyl groups, alkenyl groups, alkoxy groups, and aryl groups in chemical formula 12 are the same as in the cases of chemical formulas 10 and 11. The monomer units in chemical formula 12 may also be polyindole units.

[0158] In other examples, the bithiophene monomer unit may be the unit of the following chemical formula 13.

[0159] [ka]

[0160] In chemical formula 13, R 29 ~R 34 Each of these may independently be hydrogen, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, a hydroxyl group, or a halogen. The specific types of alkyl groups, alkenyl groups, alkoxy groups, and aryl groups in chemical formula 13 are the same as those in chemical formulas 10 and 11.

[0161] The monomer unit of the chemical formula 13 may be a polyazulene unit.

[0162] In other examples, the bithiophene monomer unit may be the unit of the following chemical formula 14.

[0163] [ka]

[0164] In chemical formula 14, X2 is a carbon atom (CR a R b ) or nitrogen atom (NR 1 ) may also be the case. In the above, R a , R band R 1 Each of these may independently be a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group.

[0165] On the other hand, the unit of chemical formula 14 may be in an unsubstituted state, or it may be substituted with one or more groups selected from the group consisting of alkyl groups, alkenyl groups, alkoxy groups, aryl groups, and halogens.

[0166] The specific types of alkyl groups, alkenyl groups, alkoxy groups, and aryl groups in the aforementioned chemical formula 14 are the same as those in the cases of chemical formulas 10 and 11.

[0167] For example, the monomer unit of chemical formula 14 may be a polyfluorene or polycarbazole unit.

[0168] In other examples, the bithiophene monomer unit may be the unit of the following chemical formula 15.

[0169] [ka]

[0170] The unit of chemical formula 15 may be unsubstituted, or it may be substituted with one or more groups selected from the group consisting of alkyl groups, alkenyl groups, alkoxy groups, aryl groups, and halogens.

[0171] The specific types of alkyl groups, alkenyl groups, alkoxy groups, and aryl groups in chemical formula 15 are the same as in the cases of chemical formulas 10 and 11. For example, the monomer unit in chemical formula 15 may be a polypyrene unit.

[0172] The conductive polymer may have a weight-average molecular weight within a predetermined range. The lower limit of the weight-average molecular weight of the conductive polymer may be approximately 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, or 95,000, and the upper limit may be 1,000,000. It may be approximately 0, 950,000, 900,000, 850,000, 800,000, 750,000, 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000, 350,000, 300,000, 250,000, 200,000, 150,000, 130,000, 110,000, or 100,000. The weight-average molecular weight may be greater than or greater than one of the lower limits selected from the listed lower limits, and less than or equal to one of the upper limits selected from the listed upper limits. The unit of the weight-average molecular weight is g / mol, which can be confirmed by the description in "2. GPC (Gel Permeation Chromatograph)" in the Examples section of this specification.

[0173] The molecular weight distribution of the conductive polymer, i.e., the ratio of the weight-average molecular weight (Mw) to the water-average molecular weight (Mn) (Mw / Mn), may be within a predetermined range. The lower limit of the molecular weight distribution may be approximately 2, 2.5, 3, or 3.5, and the upper limit may be approximately 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, or 3.7. The molecular weight distribution may be greater than or greater than one of the lower limits selected from the enumerated lower limits, and less than or less than one of the upper limits selected from the enumerated upper limits. The molecular weight distribution can be confirmed by the description in "2. GPC (Gel Permeation Chromatograph)" of the Examples section of this specification.

[0174] The polymer layer may contain a conductive substance together with the conductive polymer. The conductive substance, in combination with the conductive polymer, provides the polymer layer with the desired properties (for example, ΔV and V in formula 1). f and V i Q and R in Equation 2 3V and R 3.3V R in Equation 3 130 and R 25 It can serve the purpose of indicating things like (etc.).

[0175] As the conductive material, any material with appropriate conductivity can be used. For example, as the conductive material, one or more selected from carbon particles, carbon fibers, grapheme, graphite, carbon black, carbon nanotubes, and metal particles can be used.

[0176] The conductive material can be selected from the above and used in an appropriate form. The form of the material may be particulate (spherical, amorphous, or other form), plate-like, or fibrous, etc., but is not limited thereto.

[0177] The size of the conductive material can also be adjusted as needed. For example, the lower limit of the size of the conductive material may be around 0.01 nm, 0.1 nm, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or 60 nm, and the upper limit may be 100,000 nm, 90,000 nm, 80,000 nm, 70,000 nm, 60,000 nm, 50,000 nm, 40,000 nm, 30,000 nm, The sizes may be approximately 20,000 nm, 10,000 nm, 5,000 nm, 1,000 nm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, 600 nm, 550 nm, 500 nm, 450 nm, 400 nm, 350 nm, 300 nm, 250 nm, 200 nm, or 150 nm, 100 nm, 90 nm, 80 nm, 70 nm, or 65 nm. The sizes may be greater than or greater than one of the lower limits selected from the enumerated lower limits, and less than or less than one of the upper limits selected from the enumerated upper limits. The size of the conductive material is the average diameter (so-called D50 particle size) confirmed according to the method described in "7. Average Particle Size" of the Examples section of this specification.

[0178] The conductive material may be surface-treated to take into consideration its dispersibility, etc. Such surface treatment may achieve the desired properties (for example, ΔV and V in Equation 1). f and V i Q and R in Equation 2 3V and R 3.3V R in Equation 3 130 and R 25 This is important for ensuring a dispersion state of conductive materials that can secure Ra and Ra / T, etc.

[0179] As the surface treatment agent for the above surface treatment, a surface treatment agent having appropriate compatibility with the conductive polymer can be used. For example, the conductive substance may be surface-treated with a polyphenol compound as the surface treatment agent. A polyphenol compound means a compound that contains a structure comprising two or more linked hydroxyl groups substituted with benzene. Examples of such compounds include so-called catechol compounds (i.e., compounds containing catechol or its structure), and examples include, but are not limited to, dopamine, polydopamine, 3,4-dihydroxyphenylalanine, norephinephrine, tannic acid, humic acid, and / or lignin.

[0180] The method for surface-treating a conductive material with the surface treatment agent is not particularly limited. For example, a method of mixing the conductive material and the surface treatment agent in a suitable solvent, or a method of synthesizing or polymerizing the surface treatment agent on the surface of the conductive material can be applied.

[0181] When the conductive material is used, the ratio of the conductive material in the polymer layer can be adjusted according to the purpose. For example, the lower limit of the weight ratio of the conductive material to 100 parts by weight of the conductive polymer in the polymer layer may be around 1, 5, 10, 15, 20, 25, 30, 35, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 65, 80, 90, or 95 parts by weight, and the upper limit may be, for example, 1,000, 950, 900, 850, or 8 It may also be approximately 00 parts by weight, 750 parts by weight, 700 parts by weight, 650 parts by weight, 600 parts by weight, 550 parts by weight, 500 parts by weight, 450 parts by weight, 400 parts by weight, 350 parts by weight, 300 parts by weight, 250 parts by weight, 200 parts by weight, 150 parts by weight, 145 parts by weight, 140 parts by weight, 135 parts by weight, 130 parts by weight, 125 parts by weight, 120 parts by weight, 115 parts by weight, 110 parts by weight, 105 parts by weight, 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, or 50 parts by weight. The content may be within the range of either the lower limit selected from the listed lower limits or exceeding it, or it may be within the range of either the lower limit selected from the listed lower limits or exceeding it, and either the upper limit selected from the listed upper limits or less.

[0182] Under such ratios, the conductive material can interact appropriately with the conductive polymer, allowing for the effective formation of a polymer layer of the desired shape.

[0183] The polymer layer may contain any additional components, as long as it includes the conductive polymer and the conductive substance.

[0184] This specification discloses a method for forming the polymer layer.

[0185] As mentioned above, the polymer layer achieves the desired effect (for example, ΔV, V in Equation 1 above).f and V i Q and R in Equation 2 3V and R 3.3V R in Equation 3 130 and R 25 To express (Ra and Ra / T, etc.), the selection of long-chain hydrocarbon functional groups and / or conductive materials is important. Furthermore, controlling the arrangement of the long-chain hydrocarbon functional groups and / or the dispersion state of the conductive materials is also important, but the desired arrangement and / or dispersion state can be ensured by the manufacturing method described later.

[0186] The manufacturing method may include a step for forming a polymer layer having the above-mentioned properties.

[0187] The manufacturing method may include, for example, the steps of forming a polymer layer precursor containing the conductive polymer and the conductive substance, and heat-treating the polymer layer precursor.

[0188] The conductive polymers and the like can be manufactured by known methods. For example, methods for producing polythiophene include methods utilizing oxidative polymerization reactions and methods utilizing radical reactions, and these methods can also be applied to the process of forming the conductive polymers. Furthermore, commercially available conductive materials can be used, and their surface treatment can also be carried out by known methods.

[0189] The polymer layer precursor refers to, for example, a layer containing the conductive polymer and a conductive substance, which is converted into the polymer layer. Such a precursor can be formed by known methods, for example, by coating with a polymer solution in which the conductive polymer and the like are dispersed in a suitable solvent.

[0190] As the solvent, a suitable solvent capable of dispersing the conductive polymer and conductive substance can be selected. For example, ether-based solvents such as diethyl ether, tetrahydrofuran, dioxane, trioxane, dimethoxyethane, or toluene; aromatic hydrocarbon-based solvents such as ethylbenzene; alicyclic hydrocarbon-based solvents such as cyclohexane; tertiary amine-based solvents such as tetramethylethylenediamine (TMEDA) or hexamethylphosphoramide (HMPA) may be used, or a mixed solvent containing two or more of the above may be used, but is not limited to these.

[0191] A polymer layer precursor is formed using the polymer solution. This process can usually be carried out by coating the polymer solution onto a suitable process substrate. There are no particular restrictions on the coating method.

[0192] The above manufacturing method further includes a step of heat-treating the precursor of the polymer layer. By adjusting the conditions in this process, the orientation state of the conductive polymer (for example, the orientation state of the long-chain hydrocarbon functional groups and / or polar functional groups) and / or the dispersion state of the conductive material can be adjusted to form a polymer layer exhibiting the desired effect.

[0193] The heat treatment step can be carried out in two steps. For example, the heat treatment step may include a first step of performing a primary heat treatment on the polymer layer precursor, and a second step of performing a secondary heat treatment on the polymer layer precursor after the first step.

[0194] The conditions in the first and second steps can be adjusted to achieve the desired orientation or alignment of functional groups and the dispersion state of the conductive material.

[0195] For example, the temperature T1 of the primary heat treatment and the temperature T2 of the secondary heat treatment can be adjusted. For example, the lower limit of the ratio of temperatures T1 and T2 (T1 / T2) may be around 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, or 1.2, and the upper limit may be around 10, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, or 1.3, 1.2. The ratio may be within the range of either the lower limit or greater than or exceeding one of the lower limits selected from the enumerated lower limits, or within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or within the range of either the lower limit or greater than or exceeding one of the lower limits selected from the enumerated lower limits, and either the upper limit or less than one of the upper limits selected from the enumerated upper limits.

[0196] For example, the temperature T1 of the primary heat treatment can be adjusted within a predetermined range. For example, the lower limit of the temperature T1 may be around 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, or 140°C, and the upper limit may be around 300°C, 290°C, 280°C, 270°C, 260°C, 250°C, 240°C, 230°C, 220°C, 210°C, 200°C, 190°C, 180°C, 170°C, 160°C, 150°C, or 140°C. The temperature T1 may be within the range of either the lower limit selected from the enumerated lower limits or exceeding it, or it may be within the range of either the lower limit selected from the enumerated lower limits or exceeding it, and either the upper limit selected from the enumerated upper limits or less than it.

[0197] The ratio of the heat treatment time S1 in the primary heat treatment to the heat treatment time S2 in the secondary heat treatment can be further adjusted. For example, the lower limit of the ratio S2 / S1 is approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 70, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, or 270. It may be present, and its upper limit may be around 1,000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 290, 280, 270, 250, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, or 20. The ratio S2 / S1 may be within the range of either the lower limit or greater than or exceeding one of the lower limits selected from the enumerated lower limits, or within the range of either the upper limit or less than one of the upper limits selected from the enumerated upper limits, or within the range of either the lower limit or greater than or exceeding one of the lower limits selected from the enumerated lower limits, and either the upper limit or less than one of the upper limits selected from the enumerated upper limits.

[0198] The lower limit of the secondary heat treatment time S2 may be approximately 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours, 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, or 18 hours, and the upper limit may be approximately 50 hours, 48 ​​hours, 46 hours, 44 hours, 42 hours, 40 hours, 38 hours, 36 hours, 34 hours, 32 hours, 30 hours, 28 hours, 26 hours, 24 hours, 22 hours, 20 hours, or 18 hours. The secondary heat treatment time S2 may be within the range of either the lower limit selected from the enumerated lower limits or exceeding it, or within the range of either the upper limit selected from the enumerated upper limits or less, or within the range of either the lower limit selected from the enumerated lower limits or exceeding it, and either the upper limit selected from the enumerated upper limits or less.

[0199] The polymer layer can be formed through the above process.

[0200] This specification discloses a current collector, electrode, or electrode assembly including the polymer layer.

[0201] The current collector may include the current collector body and the polymer layer formed on the current collector body. The current collector can be used to form electrodes. For example, an electrode formed using the current collector may include the current collector and an active material layer formed on the polymer layer of the current collector. Figure 1 is a schematic cross-sectional view of a current collector including a current collector body (100) and a polymer layer (200), and Figure 2 is a diagram showing an electrode in which an active material layer (300) is formed on the polymer layer (200) of the current collector.

[0202] As shown in the drawing, in the current collector or electrode, the current collector body (100) and the polymer layer (200), and the polymer layer (200) and the active material layer (300) may be in contact with each other, and other elements may be present between them. Also, although the drawing shows that the active material layer (300) is present on only one side of the current collector body (100), the active material layer (300) may be present on both sides of the current collector body (100). In such a case, the polymer layer (200) may be present in two layers between the current collector body (100) and each of the active material layers (300) present on both sides of the current collector body (100), or it may be present in one layer between either of the active material layers (300) present on both sides and the current collector body (100).

[0203] The electrode formed by the current collector may be a negative electrode (anode) or a positive electrode (cathode) applied to a secondary battery.

[0204] As the polymer layer in the current collector and the electrode, the aforementioned polymer layer can be used. Such a polymer layer may be formed using the current collector body as a process substrate during the process of forming the polymer layer, or may be formed by a method of transferring the polymer layer formed through another process onto the current collector body.

[0205] The excellent electrical properties, adjusted PTC effect, and oxidation potential of the polymer layer enable the electrode or the secondary battery to which the electrode is applied to operate and be stored stably under normal conditions and ensure stability under abnormal conditions.

[0206] There are no particular restrictions on the current collector body, and usually, those commonly used as current collectors for the positive electrode or the negative electrode may be used.

[0207] There are no particular limitations on the type, size, shape, etc. of the current collector body as long as it does not cause a chemical change in an application device such as a secondary battery and has conductivity. Examples of materials that can be used as the current collector body include copper, aluminum, stainless steel, nickel, titanium, or fired carbon, etc., or materials obtained by surface treatment with carbon, nickel, titanium, silver, etc. on the surface of copper, aluminum, or stainless steel. The current collector body may be in the form of a film, sheet, foil, net, porous body, foam, or non-woven fabric body containing the aforementioned materials. In some cases, for the purpose of improving the adhesion to other layers such as the polymer layer or the active material layer, a known surface treatment may be applied to the surface of the current collector body.

[0208] Such a current collector body may usually have a thickness within the range of 3 μm to 500 μm, but is not limited thereto.

[0209] As the active material layer used for forming the electrode, a commonly applied layer may also be used. Usually, the active material layer contains an electrode active material. There are no particular restrictions on the specific type of the electrode active material, and usually, materials for forming the positive electrode or the negative electrode may be used.

[0210] For example, when the active material layer is the positive electrode active material layer, the electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; or a compound with the chemical formula Li 1+c1 Mn 2-c1 Lithium manganese oxides such as O4 (0 ≤ c1 ≤ 0.33), LiMnO3, LiMn2O3, or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, or Cu2V2O7; chemical formula LiNi 1-c2 M c2 Ni-site type lithium nickel oxide represented as O2 (where M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, satisfying 0.01 ≤ c2 ≤ 0.3); chemical formula LiMn 2-c3 M c3 Lithium manganese composite oxides represented as O2 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, satisfying 0.01 ≤ c3 ≤ 0.1) or Li2Mn3MO8 (where M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); lithium nickel cobalt manganese (NCM) composite oxide, lithium nickel cobalt manganese aluminum (NCMA) composite oxide, and LiMn2O4 in which part of the Li in the chemical formula is substituted with alkaline earth metal ions, etc., are examples but are not limited to these.

[0211] When the active material layer is the negative electrode active material layer, the electrode active material may be a compound capable of reversible intercalation and deintercalation of lithium. Specifically, carbon-based materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds that can alloy with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiO a(0 < a < 2), metal oxides capable of doping and undoping lithium, such as SnO2, vanadium oxide, and lithium vanadate; or composites containing the metal-based compound and the carbon-based material, such as Si-C composites or Sn-C composites, etc. may be mentioned, and any one or a mixture of two or more of these may be used.

[0212] As the negative electrode active material, a lithium thin film may be used, and as the carbon material, low-crystalline carbon, high-crystalline carbon, etc. may be used. Representative examples of low-crystalline carbon are soft carbon and hard carbon, and representative examples of high-crystalline carbon are amorphous, plate-like, flaky, spherical or fibrous natural graphite or artificial graphite, kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, mesocarbon microbeads, mesophase pitches, and high-temperature calcined carbons such as petroleum or coal tar pitch-derived cokes.

[0213] The electrode active material may be contained within the active material layer in the range of about 80 wt% to 99.5 wt% or 88 wt% to 99 wt% with respect to the total amount of the active material layer, but the ratio can be changed depending on the use and design of the electrode, etc.

[0214] The active material layer may further contain a binder. The binder plays a role in improving adhesion between the active materials and the adhesion between the active material layer and the current collector body. Examples of the binder are not particularly limited, but include, for example, PVDF (poly(vinylidene fluoride)), PVA (poly(vinyl alcohol)), SBR (styrene-butadiene rubber), PEO (poly(ethylene oxide)), CMC (carboxymethylcellulose), cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, and cyanoethyl sucrose. One or more substances can be selected and used from the group consisting of sucrose, pullulan, polymethyl methacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate.

[0215] In one example, the binder may be included in the active material layer in an amount ranging from 0.1 to 10 parts by weight or 0.5 to 5 parts by weight per 100 parts by weight of the electrode active material, but is not limited thereto.

[0216] The active material layer may further contain a conductive material as needed. Any known material can be used as the conductive material, as long as it does not cause a chemical change in the secondary battery and is conductive. For example, 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; conductive tubes such as carbon nanotubes (CNTs); metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide and / or polyphenylene derivatives, etc.

[0217] In one example, the conductive material may be included in the active material layer in an amount of 0.1 to 20 parts by weight or 0.3 to 10 parts by weight per 100 parts by weight of the electrode active material, but is not limited thereto.

[0218] The active substance layer may further contain, in addition to the aforementioned components, any necessary known components.

[0219] There are no particular limitations on the method for manufacturing the electrode by forming the active material layer on the polymer layer. Typically, the active material layer is formed by coating a slurry containing the electrode active material, binder, and conductive material onto the current collector (polymer layer), drying it, and then rolling it. Such known methods can be applied in the same manner.

[0220] This specification also discloses electrode assemblies or electrochemical elements including electrodes as described above, such as secondary batteries.

[0221] The electrochemical element may include the electrodes as a positive electrode and / or a negative electrode. As long as the electrodes of this specification are used as a negative electrode and / or a positive electrode, other configurations or methods of manufacture of the electrochemical element are not particularly limited and known methods can be applied. [Effects of the Invention]

[0222] This specification discloses a polymer layer, a method for manufacturing the same, and its applications. The polymer layer exhibits the so-called PTC (Positive Temperature Coefficient) effect at the required level when needed, and can be applied to materials that can ensure stability in applications where stability under abnormally high temperatures or flames is a concern. The polymer layer exhibits oxidation potential characteristics suitable for the application, and can stably maintain such oxidation potential characteristics even under harsh environments. The polymer layer can rapidly exhibit the PTC effect at the desired level when needed. The polymer layer has a flat surface and excellent resistance to scratches and the like. This specification discloses a method for manufacturing the polymer layer and its applications. [Brief explanation of the drawing]

[0223] [Figure 1] This is an example cross-sectional view of a current collector. [Figure 2] This is an illustrative cross-sectional view of an electrode. [Figure 3] This shows the NMR analysis results for the monomer of Production Example 2. [Modes for carrying out the invention]

[0224] The polymer layer, etc. will be described in detail below through examples or comparative examples, but the scope of the polymer layer, etc. is not limited by the following examples.

[0225] 1.NMR analysis 1 ¹H-NMR analysis was performed at room temperature (approximately 25°C) using an NMR spectrometer equipped with a triple-resonance 5 mm probe and a Bruker UltraShield spectrometer (300 MHz). The sample was diluted to a concentration of approximately 10 mg / ml in the NMR measurement solvent (CDCL3), and chemical transfer was expressed in ppm.

[0226] 2.GPC(Gel Permeation Chromatograph) The molecular weight characteristics were measured using GPC (Gel permeation chromatography). The sample was placed in a 5 mL vial and diluted with chloroform to a concentration of approximately 1 mg / mL. The calibration standard sample and the analytical sample were filtered through a syringe filter (pore size: 0.45 μm) and analyzed. The Empower 3 from Waters was used as the analysis program. The elution time of the sample was compared with the calibration curve to determine the weight-average molecular weight (Mw) and the number-average molecular weight (Mn) respectively, and the molecular weight distribution (PDI) was calculated using the ratio (Mw / Mn). The measurement conditions for GPC are as follows.

[0227] <GPC Measurement Conditions> Instrument: 2414 from Waters Columns: Three Styragel columns from Waters were used Solvent: THF (Tetrahydrofuran) Column temperature: 35 °C Sample concentration: 1 mg / mL, 1 μL injection Standard sample: Polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

[0228] 3. Measurement of Thickness The thickness of the polymer layer was measured using a KEYENCE VK-X series confocal laser microscope. A sample was prepared by cutting an aluminum foil (current collector body) with the polymer layer formed on it to a length of 3 cm in both width and height. Approximately half of the polymer layer was removed from the sample using acetone, exposing the lower aluminum foil. The aluminum foil surface of the sample without the polymer layer was placed in close contact with a flat plate, and the measurement was started. An area of ​​100 μm in both width and height was observed using the microscope, and the sample was adjusted so that the polymer layer and the exposed aluminum foil each occupied half of the observation area, and a 3D scan was performed. The average height P was measured at 10 arbitrary locations on the polymer layer within the observation area, and the average height A was measured at 10 arbitrary locations on the aluminum foil. The value obtained by subtracting the average height A from the average height P was then defined as the thickness of the polymer layer.

[0229] 4. Oxidation potential V i and V f Measurement Oxidation potential V i and V fThe following method was used for measurement. A polymer layer was formed on an aluminum foil (Al Foil) (current collector body) with a thickness of approximately 15 μm. The method for forming the polymer layer and the thickness of the polymer layer were applied in the same manner as described in each example and comparative example. A separation membrane and a lithium film were laminated on the polymer layer to produce a laminate in which aluminum foil / polymer layer / separation membrane / lithium film were sequentially laminated, and the laminate was punched out into a circle with a diameter of approximately 1.4 cm. Using a Wellcos CR2032 coin cell kit, a coin cell was manufactured using the circularly punched laminate and electrolyte. The W-SCOPE KOREA WL20C model was used for the separation membrane, a lithium film with a thickness of approximately 100 μm was used as the lithium film, and an Enchem product (1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: Ethylene Carbonate, DMC: Dimethyl Carbonate, EMC: Ethylmethyl Carbonate)) was used as the electrolyte. The oxidation potential was measured in the coin cell at approximately 25°C using an electrochemical measuring instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC). The oxidation potential was measured by injecting a cyclic voltage current (CV) into the coin cell at a scan speed of approximately 0.83 mV / sec in the range of 3 V to 4.5 V, and measuring the reaction between lithium and lithium ions (Li / Li + The oxidation potential was measured based on the following reference value. The oxidation potential V was measured after injecting the aforementioned circulating voltage current once. i The oxidation potential measured after 10 injections is called the oxidation potential V. f That's what I decided.

[0230] AC impedance resistance at 5.3V and 3.3V To confirm the electrical reactivity of the polymer layer, the AC impedance resistance was measured.

[0231] Sample preparation A laminate (aluminum foil / polymer layer / separation membrane / lithium film) was manufactured by laminating a separation membrane and a lithium film onto the polymer layer of a laminate of aluminum foil (current collector body) and a polymer layer manufactured in the example or comparative example, and the laminate was punched out into a circle with a diameter of approximately 1.4 cm. A coin cell was manufactured using the Wellcos CR2032 coin cell kit and the punched-out circular laminate and electrolyte. The W-SCOPE KOREA WL20C model was used as the separation membrane, a lithium film with a thickness of approximately 300 μm was used as the lithium film, and an Enchem product (1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: Ethylene Carbonate, DMC: Dimethyl Carbonate, EMC: Ethylmethyl Carbonate))) was used as the electrolyte.

[0232] Condition: External voltage 3V The AC impedance resistance of the fabricated coin cell was measured using the EIS (Electrochemical Impedance Spectronization) method. A voltage of 3V was applied to the coin cell at room temperature (25°C) for 10 minutes, and a Nyquist plot was obtained using the EIS measurement method in the range of 50,000Hz to 0.1Hz. The interfacial resistance R obtained in the high frequency region of the Nyquist plot was then measured. 3V The following measurements were taken. For EIS measurement, an electrochemical measuring instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC) was used.

[0233] External voltage 3.3V condition The AC impedance resistance R was measured after applying a voltage of 3V to the coin cell at room temperature (25°C) for 10 minutes, converting the applied voltage to 3.3V, and then 1 second had elapsed. 3.3V The resistor R 3V It was measured using the same method.

[0234] 6. AC impedance resistance at room temperature (25°C) and 130°C (1) AC impedance resistance R 25 Measurement The AC impedance resistance was measured using the same coin cell as used for the "AC impedance resistance at 5.3V and 3.3V" measurements described above. The AC impedance resistance of the coin cell was measured using the EIS (Electrochemical Impedance Spectronization) method. Specifically, a Nyquist plot was obtained using the EIS measurement method in the range of 50,000Hz to 0.1Hz, and the interfacial resistance obtained in the high-frequency region was measured from the obtained Nyquist plot. An electrochemical measuring instrument (potentiostat) (manufacturer: Princeton Applied Research, product name: PARASTAT-MC) was used as the EIS measuring instrument.

[0235] A voltage of 4.5V was applied to the coin cell at room temperature (25°C) for 10 minutes to maintain the doping state of the conductive polymer. Then, with the external voltage set to 0V (Open circuit voltage), the AC impedance resistance was measured after approximately 1 minute. The measured value was then used to determine the AC impedance resistance R of the polymer layer at room temperature (25°C). 25 That's what I decided.

[0236] (2) AC impedance resistance R 130 Measurement The coin cell was positioned in the center of a convection oven (Jiotec, OF3-05W) and connected to an external electrochemical instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC) to enable EIS resistance measurement. While maintaining room temperature (approximately 25°C), a voltage of 4.5V was applied to the coin cell (sample) for 10 minutes to maintain the doping state of the conductive polymer, and the oven was set to reach a final temperature of 130°C. Once the temperature reached 130°C, the external voltage was set to 0V (Open circuit voltage) (Open circuit voltage), and after approximately 1 minute, the resistance R 25 The AC impedance resistance was measured using the same method. The measured value was used to determine the AC impedance resistance R of the polymer layer at 130°C. 130 That's what I decided.

[0237] 7.Average particle size The average particle size (D50 particle size) of conductive particles was measured using a Marvern MASTERSIZER3000 instrument in accordance with the ISO-13320 standard. Toluene was used as the solvent during measurement. When the sample was dispersed in the solvent and irradiated with a laser, the laser was scattered by the dispersed sample in the solvent. Since the intensity and directionality of the scattered laser differ depending on the particle size, the average particle size can be determined by analyzing this using Mie theory. Based on the above analysis, the measurement results were converted to the particle size of a sphere with the same volume as the dispersed sample, and a volume-based cumulative graph of the particle size distribution was obtained. The particle diameter (median particle size) at 50% of the cumulative value of the graph was taken as the average particle size (D50 particle size).

[0238] 8. Arithmetic mean roughness Ra The arithmetic mean roughness Ra was measured using a KEYENCE VK-X series confocal laser microscope. A sample was prepared by cutting an aluminum foil coated with a polymer layer (current collector body) to a length and width of 3 cm each. The side of the aluminum foil sample without the polymer layer was placed in close contact with a flat plate and 3D scanned. The polymer layer region with dimensions of 100 μm in both width and length was 3D scanned. After arbitrarily selecting regions with dimensions of 50 μm in both width and length within the 3D scanned area, the arithmetic mean roughness Ra was measured using the 3D scan image.

[0239] 9. Scratch resistance Using a dust-free cloth (Hansong MIRACLEAN322 Polyester wiper), the surface of the polymer layer was wiped 10 times back and forth with a load of 100g and a speed of 27rpm. If scratches were observed visually, it was evaluated as NG; if no scratches were observed, it was evaluated as PASS.

[0240] Manufacturing Example 1: Polydopamine-coated conductive particles As conductive particles, carbon black particles (IMERYS, C.NERGY TM SUPER C65 was used. The average particle size (D50 particle size) of the conductive particles was approximately 60 nm.

[0241] A mixture was prepared by adding DHC (Dopamine hydrochloride) (CAS No. 62-31-7) to a buffer solution and stirring at room temperature (approximately 25°C). A 0.1M pH 8.5 Tris-buffer product from BioSESANG was used as the buffer solution. The concentration of DHC in the mixture was approximately 2 mg / mL. The conductive particles were dispersed in the mixture to a concentration of approximately 4 mg / mL (sonication for 1 hour), and then stirred for approximately 18 hours. As a result of this stirring, a polydopamine coating layer was formed on the surface of the conductive particles. After vacuum filtration using a paper filter, the polydopamine-coated conductive particles were obtained by vacuum drying.

[0242] Manufacturing Example 2. Synthesis of Monomer (A) The monomer of chemical formula A below was synthesized by the following method.

[0243] [ka]

[0244] 1.372 g (12.02 mmol, 1 eq) of 3-methoxythiophene and 3 g (16.83 mmol, 1.4 eq) of triethylene glycol monomethyl ether were dissolved in 100 ml of toluene with 230 mg of p-toluenesulfonic acid (p-TsOH) and mixed. The mixture was reacted under reflux at 120°C, and methanol produced by the reaction (transetherification) was removed using a 4A type molecular sieve packed in a soxhlet extractor. After refluxing the reaction mixture for 24 hours, it was quenched with water, extracted with ethyl acetate, washed with brine, and dried on magnesium sulfate (MgSO4). The solvent was removed using a rotary evaporator, and the residue was purified by column chromatography using methylene chloride / hexane (2:1) elution to obtain the target compound (monomer (A)). The NMR analysis results of the target compound (monomer (A)) are shown in Figure 3.

[0245] Manufacturing Example 3. Synthesis of conductive polymer (A) To a solution prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride, 0.7 g (2.96 mmol, 0.6 eq) of 3-dodecylthiophene, 0.3 g (1.48 mmol, 0.3 eq) of 3-hexylthiophene, 0.12 g (0.49 mmol, 0.1 eq) of monomer (A) from Production Example 2, and 0.37 g (1.23 mmol, 0.3 eq) of pyrrole were added, and the mixture was polymerized at 25°C for 24 hours to produce conductive polymer (A). The molar ratio of 3-dodecylthiophene units (I), 3-hexylthiophene units (II), monomer (A) units (III) from Production Example 2, and pyrrole (IV) units in the conductive polymer (A) was approximately 2.96:1.48:0.49:1.23 (I:II:III:IV). The polymerization solution was placed in a permeable membrane with a molecular weight of cut-off (MWCO) of 5000, and then immersed in 200 ml of acetonitrile to remove unreacted iron chloride and monomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to obtain conductive polymer (A). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the conductive polymer (A) were approximately 99,000 g / mol and 28,000 g / mol, respectively.

[0246] Example 1. A polymer solution was prepared by dispersing a mixture of the conductive polymer (A) from Production Example 3 and the polydopamine-coated conductive particles (P) from Production Example 1 in a weight ratio of 70:30 (A:P) in toluene to a concentration of approximately 4% by weight. The polymer solution was prepared by dispersing the mixture at a temperature of approximately 30°C for approximately 4 hours using an ultrasonic disperser. The polymer solution was then coated onto the current collector body using the Meyer bar coating method. The coating layer was then maintained in a drying oven at a temperature of approximately 140°C for approximately 4 minutes (primary heat treatment). Subsequently, the current collector body with the coated layer was placed in the oven and subjected to heat treatment at a temperature of approximately 110°C for approximately 18 hours (secondary heat treatment) to form a polymer layer with a thickness of approximately 400 nm. An Al foil with a thickness of approximately 15 μm was used as the current collector body.

[0247] Example 2. A polymer layer was formed in the same manner as in Example 1, except that a mixture of the conductive polymer (A) from Production Example 3 and the polydopamine-coated conductive particles (P) from Production Example 1 was used in a weight ratio of 60:40 (A:P) during the preparation of the polymer solution.

[0248] Example 3. A polymer layer was formed in the same manner as in Example 1, except that a mixture of the conductive polymer (A) from Production Example 3 and the polydopamine-coated conductive particles (P) from Production Example 1 were used in a 50:50 weight ratio (A:P) during the preparation of the polymer solution.

[0249] Comparative Example 1. A polymer solution was prepared by dispersing the conductive polymer (A) from Manufacturing Example 3 in toluene to a concentration of approximately 4% by weight. During the preparation of the polymer solution, an ultrasonic disperser was used to disperse the conductive polymer at a temperature of approximately 30°C for approximately 4 hours. The polymer solution was coated onto the current collector body using a Meyer bar coating method and dried in a drying oven at approximately 140°C for approximately 4 minutes to form a polymer layer with a thickness of approximately 400 nm. An Al foil with a thickness of approximately 15 μm was used as the current collector body.

[0250] Comparative Example 2. As conductive particles, uncoated polydopamine-coated carbon black particles (IMERYS, C·NERGY TM SUPER C65 was used. A polymer solution and polymer layer were formed in the same manner as in Example 1 using a mixture of the conductive polymer (A) from Production Example 3 and the carbon black particles (C) in a weight ratio of 90:10 (A:P).

[0251] Comparative Example 3. As conductive particles, uncoated polydopamine-coated carbon black particles (IMERYS, C·NERGY TM SUPER C65 was used. A polymer solution and polymer layer were formed in the same manner as in Example 1 using a mixture of the conductive polymer (A) from Production Example 3 and the carbon black particles (C) in a weight ratio of 80:20 (A:P).

[0252] Comparative Example 4. As conductive particles, uncoated polydopamine-coated carbon black particles (IMERYS, C·NERGY TM SUPER C65 was used. A polymer solution was prepared in the same manner as in Example 1 using a mixture of the conductive polymer (A) from Production Example 3 and the carbon black particles (C) in a weight ratio of 10:4 (A:P). Subsequently, a polymer layer was formed using the polymer solution in the same manner as in Example 1, but without secondary heat treatment, only primary heat treatment was performed to form the polymer layer.

[0253] Table 1 shows the above "4. Oxidation Potential V i and V f The oxidation potential V measured in the "Measurement of" section i and V f And the oxidation potential is given by formula 100 × (V) f -V i ) / V i This is a summary of the △ calculated by substituting the values. In Table 1, the oxidation potential V iand V f The unit of is V, and the unit of △V is %.

[0254] [Table 1]

[0255] Table 1 shows that the polymer layer of the example has a low oxidation potential V i This shows that such a low oxidation potential is stably maintained even after repeated injection of circulating voltage current.

[0256] Table 2 shows the R values ​​measured for the "AC impedance resistance at 5.3V and 3.3V" and "6. AC impedance resistance at room temperature (25°C) and 130°C" measurement items. 3V , R 3.3V , R 25 and R 130 This summarizes the results. In Table 2, Q is equal to the aforementioned R 3V to R 3.3V The value obtained by dividing by (R 3V / R 3.3V ) and P is R 130 to R 25 The value obtained by dividing by (R 130 / R 25 )

[0257] In Table 2, R 3V , R 3.3V , R 25 , R 130 The unit is Ω.

[0258] [Table 2]

[0259] The results in Table 2 show that the polymer layer in the example exhibits a rapid and significant decrease in impedance immediately after the external voltage changes from 3V to 3.3V. This indicates that the electrical responsiveness of doping / dedoping of the polymer layer is very fast. Furthermore, it can be confirmed that the resistance increases efficiently with temperature changes, resulting in a high P value.

[0260] Table 3 summarizes the evaluation results for "8. Arithmetic Mean Roughness Ra" and "9. Scratch Resistance," along with the thickness of each polymer layer. In Table 3, the units for thickness and Ra are nm.

[0261] [Table 3]

[0262] The results in Table 3 confirm that, in the case of the polymer layer of the example, even when containing conductive particles at a level equivalent to that of the comparative example, it exhibits a low Ra and stably maintains scratch resistance. [Explanation of symbols]

[0263] 100: Current collector body 200: Polymer layer 300: Active material layer

Claims

1. It includes conductive polymers and conductive materials, The oxidation potential is 4V or less. A polymer layer characterized in that the absolute value of △V in the following formula 1 is 3% or less: [Formula 1] △V=100×(V f- V i ) / V i V in Equation 1 i This refers to the Li / Li of the polymer layer after one cyclic voltage current injection. + This is the reference oxidation potential, V f The Li / Li of the polymer layer after 10 cycles of circulating voltage current injection. + The reference oxidation potential is used, and the circulating voltage current injection is performed in the range of 3V to 4.5V at a scan speed of 0.83mV / second.

2. The polymer layer according to claim 1, characterized in that Q in the following formula 2 is 10 or more: [Formula 2] Q=R 3V / R 3.3V R in Equation 2 3V R is the AC impedance resistance of the polymer layer at 25°C and 3V. 3.3V This is the AC impedance resistance of the polymer layer after 1 second has elapsed since changing the above conditions of 25°C and 3V to 25°C and 3.3V.

3. The polymer layer according to claim 1, characterized in that its arithmetic mean roughness Ra is 200 nm or less.

4. The polymer layer according to claim 1, characterized in that the ratio Ra / T of the arithmetic mean roughness Ra of the polymer layer to the thickness T of the polymer layer is 0.5 or less.

5. The polymer layer according to claim 1, characterized in that P calculated by the following formula 3 is 60 or more: [Formula 3] P=R 130 / R 25 R in Equation 3 25 R is the AC impedance resistance of the polymer layer at 25°C. 130 This is the AC impedance resistance of the polymer layer at 130°C.

6. The polymer layer according to claim 1, characterized in that the conductive polymer has long-chain hydrocarbon functional groups.

7. The polymer layer according to claim 6, characterized in that the conductive polymer contains, as long-chain hydrocarbon functional groups, a first hydrocarbon functional group having 10 or more carbon atoms and a second hydrocarbon functional group having 9 or fewer carbon atoms.

8. The polymer layer according to claim 1, characterized by containing the functional group of the following chemical formula 1: 【Chemistry 1】 In chemical formula 1, L 1 L is a single bond, an alkylene group, or an alkylidene group. 2 R is an alkylene group or alkylidene group, 1 m is a hydrogen atom or an alkyl group, and m is a number in the range of 1 to 10.

9. The polymer layer according to claim 1, characterized in that the conductive polymer comprises thiophene monomer units and bithiophene monomer units.

10. The polymer layer according to claim 9, characterized in that the bithiophene monomer unit is an aromatic monomer unit or a nitrogen-containing heterocyclic monomer unit.

11. The polymer layer according to claim 9, characterized in that the molar ratio of thiophene monomer units in the conductive polymer is 70 mol% or more, and there are 0.05 moles or more of bithiophene monomer units per mole of thiophene monomer units.

12. The polymer layer according to claim 9, characterized in that the bithiophene monomer unit is one or more units selected from the group consisting of units of the following chemical formulas 10 to 15: 【Chemistry 2】 In chemical formula 10, R 18 , R 19 and R 20 These are, independently, hydrogen, a polar functional group, or a hydrocarbon functional group: 【Transformation 3】 In chemical formula 11, L 11 These are single bonds, alkylene groups, alkylidene groups, O or NR 1 And the R 1 is a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group: 【Chemistry 4】 In chemical formula 12, X 1 is S, O or NR 1 And the R 1 R is a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group. 25 ~R 28 Each of these is independently a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, or a halogen: 【Transformation 5】 In chemical formula 13, R 29 ~R 34 Each of these is independently a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, a hydroxyl group, or a halogen: 【Transformation 6】 In chemical formula 14, X 2 CR a R b or NR 1 And the R a , R b and R 1 Each of these is independently a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group, and the unit of chemical formula 14 is either unsubstituted or substituted with one or more selected from the group consisting of alkyl groups, alkenyl groups, alkoxy groups, aryl groups, and halogens: 【Transformation 7】 The units of chemical formula 15 are either unsubstituted or substituted with one or more groups selected from the group consisting of alkyl groups, alkenyl groups, alkoxy groups, aryl groups, and halogens.

13. The polymer layer according to claim 1, characterized in that the conductive material is one or more selected from the group consisting of carbon particles, carbon fibers, graphene, graphite, carbon black, carbon nanotubes, and metal particles.

14. The polymer layer according to claim 1, characterized in that the conductive material is surface-treated with a polyphenol compound.

15. A first step involves performing a primary heat treatment on a polymer layer precursor containing a conductive polymer and a conductive substance, and The process includes a second step of performing a secondary heat treatment on the polymer layer precursor that has undergone the first step, The heat treatment temperature T of the primary heat treatment 1 The heat treatment temperature T of the aforementioned secondary heat treatment 2 Ratio T 1 / T 2 A method for producing a polymer layer, characterized in that the ratio is 0.1 or higher.

16. Heat treatment time S for secondary heat treatment 2 Heat treatment time S of the primary heat treatment 1 Ratio S 2 / S 1 A method for producing a polymer layer according to claim 15, characterized in that the value is 50 or more.

17. Current collector body, and A current collector characterized by comprising a polymer layer according to any one of claims 1 to 14 formed on one or both sides of the current collector body.

18. Current collector body, A polymer layer according to any one of claims 1 to 14, formed on one or both sides of the current collector body, and An electrode characterized by including an active material layer formed on the polymer layer.

19. An electrode assembly characterized by including the electrode described in claim 18.

20. A secondary battery characterized by including the electrode assembly described in claim 19.

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