Current collector for electrodes

Abstract

This specification discloses a current collector for an electrode and uses thereof. The current collector for an electrode exhibits excellent electrical properties, including low resistance, under normal conditions, such as in a secondary battery, and can ensure stability through increased resistance under abnormal conditions. This specification also discloses uses of the current collector for an electrode.

Description

Technical Field

[0001] Mutual citation with related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0135124 filed on October 19, 2022, and all the contents of the documents of the patent application are included as part of this specification.

[0002] Technical field This specification discloses a current collector for an electrode and its uses.

Background Art

[0003] Energy storage technologies are expanding their application areas to mobile phones, tablets, laptops, and even electric vehicles.

[0004] As the data processing speed of mobile devices such as mobile phones and tablets increases and their usage time becomes longer, the development of secondary batteries with high energy density, operating potential, long cycle life, and low self-discharge rate is underway.

[0005] In line with the suppression of the production of automobiles driven by internal combustion engines in major developed countries to solve global warming and air pollution, major automobile manufacturers are also developing various electric vehicles while emphasizing the importance of secondary batteries with high energy density, high discharge voltage, and output stability as their power sources.

[0006] However, along with the above trends, the frequency of ignition or explosion accidents caused by overcharging, high-temperature exposure, or external impacts in devices and automobiles using secondary batteries as energy sources is also increasing.

[0007] The main cause of such accidents is known to be a short circuit, which occurs when 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 external stimuli, the aforementioned short circuit can occur due to the contraction of the separator membrane caused by the rise in the 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 is concentrated 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 current collectors for electrodes and their applications. The objective of this specification is to disclose current collectors for electrodes that exhibit excellent electrical characteristics, such as low resistance, under normal conditions without affecting the performance and operation of secondary batteries, and that ensure stability under abnormal conditions. Another objective of this specification is to disclose applications for said current collectors for electrodes. [Means for solving the problem]

[0010] In this specification, the term "room temperature" means the natural temperature without heating or cooling. For example, room temperature may be any temperature within the range of 10°C to 30°C, or approximately 23°C, 25°C, or 27°C. Where the measurement temperature affects the physical properties mentioned herein, unless otherwise specified, those properties are those measured at room temperature. Unless otherwise specified, the unit of temperature in this specification is Celsius (°C).

[0011] In this specification, the term "atmospheric pressure" means the natural pressure that is not pressurized or depressurized, and typically atmospheric pressure can mean a pressure of approximately 730 mmHg to 790 mmHg. In cases where the measurement pressure affects the physical properties mentioned herein, unless otherwise specified, those physical properties are those measured at atmospheric pressure.

[0012] In this specification, if the measured humidity affects the results of any physical property mentioned herein, unless otherwise specified, the physical property shall be measured at standard humidity conditions.

[0013] Standard humidity refers to a relative humidity within the range of 40% to 60%, for example, a relative humidity of around 55% or 60%.

[0014] In this specification, the term "normal state" means the normal operating state (e.g., the normal charging or discharging state of the secondary battery) or storage state of the secondary battery.

[0015] In this specification, the term "abnormal condition" means a hazardous condition in which an abnormal flow of electric charge, abnormal heat generation or explosion occurs due to an external shock and / or short circuit, or in which the likelihood of such an abnormal condition occurring is increased.

[0016] This specification discloses current collectors for electrodes.

[0017] The electrode current collector may include a current collector body and a polymer layer formed on the body. The electrode current collector may be used to form an electrode. For example, an electrode formed using the electrode current collector may include the electrode current collector and an active material layer formed on the polymer layer of the current collector. Figure 1 is a diagram showing an electrode in which an active material layer 300 is formed on the polymer layer 200 of an electrode current collector including a current collector body 100 and a polymer layer 200.

[0018] As shown in the drawing, 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. In addition, although the drawing shows a case where 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 each of the active material layers 300 present on both sides of the current collector body 100 and the current collector body 100, or it may be present in one layer between any one of the active material layers 300 present on both sides and the current collector body 100.

[0019] The electrode formed by the current collector for the electrode may be a negative electrode (anode) or a positive electrode (cathode) applied to a secondary battery.

[0020] The polymer layer may be designed to exhibit a so-called PTC (positive temperature coefficient) effect. Therefore, the polymer layer can variably control the charge transfer in the current collector or electrode depending on the temperature.

[0021] By applying the polymer layer, the electrode exhibits excellent electrical properties, including low resistance, under normal conditions, and ensures stability through an increase in resistance under abnormal conditions.

[0022] For a polymer layer to be applied to an electrode and exhibit the aforementioned effect, the tendency of the PTC effect exhibited by the polymer layer must be controlled. The PTC effect is an effect in which resistance increases in proportion to temperature. For example, if the increase in resistance of the polymer layer occurs under normal conditions, stable operation of secondary batteries and the like becomes impossible.

[0023] The PTC effect of a properly designed polymer layer enables stable operation of the secondary battery under normal conditions, suppresses abnormal temperature increases under abnormal conditions, and also reduces the rate of such temperature increases.

[0024] The polymer layers disclosed herein have controlled compositions of the conductive copolymer applied and methods for forming the polymer layers, thereby enabling the desired PTC effect. Such polymer layers can suppress abnormal overcurrents through the increase in resistance under abnormal conditions, thereby preventing so-called thermal runaway (TR) or thermal propagation (TP) phenomena, and can reduce heat generation and explosion hazards by preventing volume expansion due to internal gas generation.

[0025] The polymer layer disclosed herein can maintain stable oxidation potential and electrical properties under normal conditions by controlling the temperature at which the PTC effect occurs.

[0026] As an example, the upper limit of the DC resistance of the polymer layer, electrode current collector, or electrode at 25°C is 10 4 Ω.cm, 9500Ω.cm, 9000Ω.cm, 8500Ω.cm, 8000Ω.cm, 7500Ω.cm, 7000Ω.cm, 6500Ω.cm, 6000Ω.cm, 5500Ω.cm, 5000Ω.c m, 4500Ω.cm, 4000Ω.cm, 3500Ω.cm, 3000Ω.cm, 2500Ω.cm, 2000Ω.cm, 1500Ω.cm, 1000Ω.cm, 950Ω.cm, 900Ω.cm, 850 The DC resistance may be approximately Ω.cm, 800Ω.cm, 750Ω.cm, 700Ω.cm, 650Ω.cm, 600Ω.cm, 550Ω.cm, 500Ω.cm, 450Ω.cm, or 400Ω.cm, with the lower limit being approximately 10Ω.cm, 50Ω.cm, 100Ω.cm, 150Ω.cm, 200Ω.cm, 250Ω.cm, 300Ω.cm, 350Ω.cm, 400Ω.cm, 450Ω.cm, or 500Ω.cm. The DC resistance may be within or below any of the upper limits mentioned above; or it may be within or below any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above. The DC resistance is measured by the method described in "5. DC Resistance Measurement Method" of the Examples in this Specification.

[0027] The upper limit of the AC impedance resistance of the polymer layer, electrode current collector, or electrode is 10 3 The AC impedance resistance may be approximately Ω, 950Ω, 900Ω, 850Ω, 800Ω, 750Ω, 700Ω, 650Ω, 600Ω, 550Ω, 500Ω, 450Ω, 400Ω, 350Ω, 300Ω, 250Ω, 200Ω, 150Ω, 100Ω, 95Ω, 90Ω, 85Ω, 80Ω, 75Ω, 70Ω, 65Ω, 60Ω, 55Ω, or 50Ω, with its lower limit being approximately 10Ω, 15Ω, 20Ω, 25Ω, 30Ω, 35Ω, 40Ω, 45Ω, 50Ω, 55Ω, 60Ω, 65Ω, or 70Ω. The AC impedance resistance may be within or below any of the upper limits mentioned above; or it may be within or below any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above. The aforementioned AC impedance resistance was measured using the method described in "6. Interface Resistance (AC Impedance Resistance)" of the Examples in this Specification.

[0028] Because the polymer layer, electrode current collector, or electrode exhibits the DC resistance and / or AC impedance resistance, the secondary battery or electrode assembly to which the polymer layer, etc., is applied can operate or be stored stably under normal conditions.

[0029] The current collector and electrode to which the polymer layer is applied exhibit a PTC effect, where resistance increases under abnormal conditions, thereby ensuring stability.

[0030] For example, the polymer layer, the current collector for the electrode, or the electrode can exhibit characteristics such that △R1 in the following formula 1 is within a predetermined range.

[0031] [Formula 1] △R1=Max{(R n+5 / R n ) / 5}

[0032] In Equation 1, R n R is the DC resistance at any temperature n°C within the range of 25°C to 135°C. n+5is the DC resistance at a temperature (n + 5)°C, which is 5°C higher than the temperature n°C, and Max{(R n+5 / R n ) / 5} is the maximum value of (R n+5 / R n ) / 5 values confirmed within the temperature range of 25°C to 135°C.

[0033] ΔR1 in Equation 1 is measured for the coin cell to which the polymer layer is applied, and the specific method is described in "7. Measurement of Maximum Resistance Change Rate (DC Resistance)" in the Examples. In the method for confirming the ΔR1, the initial temperature is 25°C and the final temperature is 135°C. The DC resistance is measured at each temperature while increasing the temperature by 5°C from the initial temperature of 25°C to confirm the R n+5 and R n . For example, when n is 90, R 95 / R 90 is the ratio of the DC resistance at 95°C to the DC resistance at 90°C. For example, when ΔR1 shows 100 Ω·cm / °C or more at any temperature within the temperature range of 25°C to 135°C, it means that the resistance of the polymer layer, the current collector for the electrode, or the electrode rises relatively rapidly at any temperature within the temperature range.

[0034] The lower limit of the ΔR1 can be about 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100, 150, 200, 250, 300, 350, or 400, and the upper limit can be about 1,000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, or 100. The unit of the ΔR1 is Ω·cm / °C. The ΔR1 may be within the range that is any one of the lower limits described above or exceeds the lower limit; or may have a range between any one of the lower limits described above or exceeds the lower limit while being less than or below any one of the upper limits described above.

[0035] Through the above characteristics, the electrode to which the polymer layer is applied can ensure the stability of a secondary battery or the like in an abnormal state.

[0036] The temperature at which the aforementioned ΔR1 is confirmed, i.e., R n The lower limit of the temperature may be around 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, or 95°C, and the upper limit may be around 200°C, 190°C, 180°C, 170°C, 160°C, 150°C, 140°C, 130°C, 120°C, 110°C, 100°C, or 90°C. The temperature may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, but within a range of any lower limit or more than any of the lower limits mentioned above. The temperature is adjusted to a temperature at which an abnormal condition occurs or is likely to occur. When a polymer layer exhibiting the aforementioned characteristics is applied, the electrode, electrode assembly, or secondary battery can maintain stable performance under abnormal conditions, while also maintaining stable performance under normal storage conditions at relatively high temperatures, and under high-temperature charging and discharging conditions.

[0037] The polymer layer, electrode current collector, or electrode can exhibit characteristics such that ΔR2 in the following equation 2 is within a predetermined range.

[0038] [Formula 2] △R² = Max{(R z+5 / R z ) / 5}

[0039] In equation 2, R z R is the AC impedance resistance at any temperature n°C within the range of 25°C to 135°C. z+5 This is the AC impedance resistance at a temperature (n+5)°C, which is 5°C higher than the aforementioned temperature n°C, and Max{(R z+5 / R z ) / 5} was confirmed within the temperature range of 25℃ to 135℃ (R z+5 / R z ) / 5 is the maximum value among them.

[0040] The ΔR2 in Equation 2 is measured for a coin cell to which the polymer layer is applied, and the specific method is described in "8. Measurement of Maximum Resistance Change Rate (AC Impedance)" of the Examples. In the method for confirming ΔR2, the initial temperature is 25°C and the final temperature is 135°C. The AC impedance resistance is measured at each temperature while increasing the temperature by 5°C at the initial temperature of 25°C, and the ΔR2 is determined. z+5 and R z Check this. For example, if n is 90, then R 95 / R 90 This is the ratio of the AC impedance resistance at 95°C to the AC impedance resistance at 90°C. For example, if ΔR2 is 10Ω / °C or higher at any temperature within the temperature range of 25°C to 135°C, it means that the resistance of the polymer layer, electrode current collector, or electrode increases relatively rapidly at any temperature within that temperature range.

[0041] The lower limit of ΔR2 may be approximately 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 33, 34, 36, 38, 40, 42, or 44, and its upper limit may be approximately 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 18, 16, 14, 12, or 10. The unit of ΔR2 is Ω / ℃. ΔR2 may be less than or equal to any of the upper limits mentioned above, greater than or equal to any of the lower limits mentioned above, or less than or equal to any of the upper limits mentioned above, while being greater than or equal to any of the lower limits mentioned above.

[0042] Through the aforementioned characteristics, electrodes to which the polymer layer is applied can ensure the stability of secondary batteries and the like under abnormal conditions.

[0043] The temperature at which ΔR2 in the aforementioned range is observed, i.e., R zThe lower limit of the temperature may be around 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, or 95°C, and the upper limit may be around 200°C, 190°C, 180°C, 170°C, 160°C, 150°C, 140°C, 130°C, 120°C, 110°C, 100°C, or 90°C. The temperature may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any lower limit or more than any of the lower limits mentioned above. The temperature is adjusted to a temperature at which an abnormal condition occurs or is likely to occur. When a polymer layer exhibiting the aforementioned characteristics is applied, the electrode, electrode assembly, or secondary battery can maintain stable performance under abnormal conditions, while also maintaining stable performance under normal storage conditions at relatively high temperatures, and under high-temperature charging and discharging conditions.

[0044] The polymer layer, electrode current collector, or electrode can exhibit characteristics such that the absolute value of △R3 in the following equation 3 is within a predetermined range.

[0045] [Formula 3] △R3 = 100 × (C1 - C2) / C1

[0046] In Equation 3, C1 is the discharge capacity at room temperature (approximately 25°C), and C2 is the discharge capacity after storage at 70°C for 60 hours. C1 and C2 in Equation 3 are the discharge capacities measured for coin cells to which the polymer layer is applied, and the specific method for measuring these capacities is described in "9. Discharge Capacity Measurement" of the Examples.

[0047] The upper limit of the absolute value of △R3 in Equation 3 may be approximately 10%, 9.5%, 9%, 8.5%, 8%, 7.5%, 7%, 6.5%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, or 1%, and its lower limit may be approximately 0%, 0.5%, or 1.5%. The range of the absolute value may be within or below any of the upper limits mentioned above; or it may be within or below any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above. By ensuring the above characteristics, the performance of the current collector, electrode, or secondary battery to which the polymer layer is applied can be stably maintained even when the operation and storage of the current collector, electrode, or secondary battery proceed under normal conditions where the temperature is relatively high.

[0048] The polymer layer, current collector for the electrode, or electrode can exhibit characteristics such that the absolute value of △R4 in the following equation 4 is within a predetermined range.

[0049] [Formula 4] △R4 = 100 × (C1 - C3) / C1

[0050] In Equation 4, C1 is the discharge capacity at room temperature (approximately 25°C), and C3 is the discharge capacity after storage at 130°C for 10 minutes. C1 and C3 in Equation 4 are the discharge capacities measured for coin cells to which the polymer layer is applied, and the specific method for measuring these capacities is summarized in "10. Discharge Capacity Measurement" of the Examples.

[0051] The lower limit of the absolute value of △R4 in Equation 4 may be around 15%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, or 68%, and its upper limit may be around 200%, 180%, 160%, 140%, 120%, 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 50%, 40%, 30%, or 20%. The range of the absolute value may be within the range that is greater than or greater than any of the lower limits mentioned above; or it may be within the range that is less than or equal to any of the upper limits mentioned above, but greater than or greater than any of the lower limits mentioned above.

[0052] Through the aforementioned characteristics, electrodes to which the polymer layer is applied can ensure the stability of secondary batteries and the like under abnormal conditions.

[0053] The aforementioned characteristics can be achieved through the introduction of a polymer layer, as described later.

[0054] For the current collector body, you can use the same type of current collector body that is normally used for the positive or negative electrode, without any particular restrictions.

[0055] The type, size, and shape of the current collector body are not particularly limited, as long as it is conductive without inducing chemical changes in the application device such as a secondary battery. Examples of materials that can be used as the current collector body include copper, aluminum, stainless steel, nickel, titanium, or calcined carbon, or materials in which the surface of copper, aluminum, or stainless steel has been surface-treated with carbon, nickel, titanium, or silver. The current collector body may take the form of a film, sheet, foil, net, porous body, foam, or nonwoven fabric containing the material. In some cases, known surface treatments may be performed on the surface of the current collector body to improve adhesion to other layers such as a polymer layer or an active material layer.

[0056] Such current collector bodies can typically have a thickness in the range of 3 μm to 500 μm, but are not limited to this range.

[0057] The active material layer used to form the electrodes can also be a layer that is normally applied.

[0058] Typically, the active material layer includes an electrode active material. There are no particular restrictions on the specific type of electrode active material; typically, a material that forms the positive or negative electrode can be used.

[0059] For example, if the active material layer is a 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 Li1+c1M n2 -c1O4(0≦c1≦0.33), LiM n Lithium manganese oxides such as O3, 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); these may include, but are not limited to, lithium nickel cobalt manganese (NCM) composite oxides, lithium nickel cobalt manganese aluminum (NCMA) composite oxides, and LiMn2O4 in which part of the Li in the chemical formula is substituted with alkaline earth metal ions.

[0060] When the active material layer is a negative electrode active material layer, as the electrode active material, a compound capable of reversible intercalation and deintercalation of lithium can be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying 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 such as SnO2, vanadium oxide, and lithium vanadium oxide that can be doped and undoped with lithium; or composites containing the metallic compound and the carbonaceous material such as Si-C composite or Sn-C composite, etc. can be mentioned, and any one or a mixture of two or more of these can be used.

[0061] As the negative electrode active material, a lithium thin film may be used, and as the carbon material, low-crystalline carbon and high-crystalline carbon etc. may be used. Representative low-crystalline carbons are soft carbon and hard carbon, and representative high-crystalline carbons 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.

[0062] 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% based on the total weight of the active material layer, but the ratio can be changed depending on the use and design of the electrode, etc.

[0063] The active material layer may additionally contain a binder. The binder plays a role in improving adhesion between the active materials and between the active material layer and the current collector body. Examples of the binder are not particularly limited and include, for example, PVDF (Poly(vinylidene fluoride)), PVA (poly(vinyl alcohol)), SBR (styrene butadiene rubber), PEO (poly(ethylene oxide)), CMC (carboxyl methyl cellulose), cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, and cyanoethyl sucrose. One or more substances may be selected and used from the group consisting of sucrose, pullulan, polymethyl methacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate.

[0064] The binder may, for example, be included in the active material layer in an amount of 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.

[0065] The active material layer may optionally contain additional conductive materials. Any known conductive material can be used without particular limitation, as long as it is conductive without inducing chemical changes in the secondary battery. For example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, kechen 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; and other conductive materials.

[0066] The conductive material may, for example, 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.

[0067] The active material layer may also contain additional known components as needed, in addition to the components described above.

[0068] The polymer layer present on the current collector body may contain a conductive polymer. A conductive polymer is a polymer that exhibits conductivity through a conjugated system of polymer chains and / or doping, as is well known.

[0069] As the conductive polymer, a polymer having so-called PTC (Positive Temperature Coefficient) properties can be used, and by controlling the tendency of the PTC effect and oxidation potential of the polymer, electrodes exhibiting the aforementioned properties can be effectively formed.

[0070] The polymer layer may contain only the conductive polymer, or it may contain the conductive polymer and other necessary additives. For example, the lower limit of the content of the conductive polymer in the polymer layer may be approximately 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% by weight, based on the total weight of the polymer layer, and the upper limit may be approximately 100%, 95%, 90%, or 85% by weight, based on the total weight of the polymer layer. The range of the content may be within or below any of the upper limits mentioned above; or within or above any of the lower limits mentioned above; or within or below any of the upper limits mentioned above, while being within or above any of the lower limits mentioned above.

[0071] The oxidation potential of the conductive polymer or polymer layer can be adjusted for the purpose. The method for measuring the oxidation potential is described in the examples herein. The oxidation potential is determined by lithium and lithium ions (Li / Li + This measurement is based on the reference value. The method for measuring the oxidation potential is described in "4. Method for Measuring Oxidation Potential" of the Examples in this specification.

[0072] The lower limit of the oxidation potential may be approximately 2V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V, or 3.7V, and the upper limit may be approximately 5V, 4.9V, 4.8V, 4.7V, 4.6V, 4.5V, 4.4V, 4.3V, 4.2V, 4.1V, 4.0V, 3.9V, 3.8V, 3.7V, 3.6V, or 3.5V. The oxidation potential may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any of the lower limits mentioned above. By using a conductive polymer having the oxidation potential described above, polymer layers and electrodes with the desired properties can be effectively formed.

[0073] 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 is 30,000 g / mol, 35,000 g / mol, 40,000 g / mol, 45,000 g / mol, 50,000 g / mol, 55,000 g / mol, 60,000 g / mol, 65,000 g / mol, 70,000 g / mol, 75,000 g / mol, 80,000 g / mol, 85,000 g / mol, 90,000 g / mol, 95,000 g / mol, 100,000 g / mol, 105,000 g / mol, 110,000 g / mol, 115,000 g / mol, 120,000 g / mol, 125,000 g / mol, 130,000 g / mol or 1 It is possible to have a concentration of around 35,000 g / mol, and its upper limit may be around 1,000,000 g / mol, 950,000 g / mol, 900,000 g / mol, 850,000 g / mol, 800,000 g / mol, 750,000 g / mol, 700,000 g / mol, 650,000 g / mol, 600,000 g / mol, 550,000 g / mol, 500,000 g / mol, 450,000 g / mol, 400,000 g / mol, 350,000 g / mol, 300,000 g / mol, 250,000 g / mol, 200,000 g / mol, 150,000 g / mol, or 110,000 g / mol. The weight-average molecular weight may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or greater than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or greater than any lower limit or greater than any of the lower limits mentioned above. By using a conductive polymer having such a weight-average molecular weight, polymer layers and electrodes with the desired properties can be effectively formed.

[0074] The molecular weight distribution of the conductive polymer, i.e., the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), can be within a predetermined range. The lower limit of the molecular weight distribution may be around 2, 2.5, 3, 3.5, 4, or 4.5, and the upper limit may be around 8, 7.5, 7, 6.5, 6, 5.5, or 5. The molecular weight distribution may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any lower limit or more than any of the lower limits mentioned above. By using a conductive polymer having such a molecular weight distribution, polymer layers, current collectors for electrodes, and electrodes with the desired properties can be effectively formed.

[0075] The weight-average molecular weight and molecular weight distribution can be measured according to the method described in "2. GPC (Gel Permeation Chromatograph)" of the Examples in this specification.

[0076] The conductive polymer may be a thiophene polymer. In this specification, the term "polythiophene" means a polymer containing a certain level or more of thiophene monomer units. By applying a thiophene polymer as the conductive polymer, the desired polymer layer can be efficiently formed.

[0077] The lower limit of the ratio of thiophene units in the thiophene polymer may be approximately 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, or 90 mol% relative to the total polymer units, and the upper limit may be approximately 100 mol%, 95 mol%, or 90 mol%. The ratio of thiophene units may be within a range that is greater than or greater than any of the lower limits mentioned above; or it may be less than or equal to any of the upper limits mentioned above, while being within a range that is greater than or greater than any of the lower limits mentioned above.

[0078] In this specification, the term "thiophene unit" means a unit formed by the polymerization of monomers of the thiophene series, and the monomers of the thiophene series mean monomers containing a thiophene skeleton.

[0079] To exhibit appropriate properties, the conductive polymer may be one that contains thiophene units having long-chain hydrocarbon groups (hereinafter referred to as first thiophene units) and thiophene units having short-chain hydrocarbon groups (hereinafter referred to as second thiophene units). Such a conductive polymer is a conductive copolymer.

[0080] In this specification, the term "long-chain hydrocarbon functional group" means a monovalent hydrocarbon group having a certain number of carbon atoms or more, or a monovalent functional group containing a monovalent hydrocarbon group having the aforementioned certain number of carbon atoms or more.

[0081] In this specification, the term "short-chain hydrocarbon functional group" means a monovalent hydrocarbon group having a number of carbon atoms below a certain level, or a monovalent functional group containing a monovalent hydrocarbon group having a number of carbon atoms below the certain level.

[0082] The lower limit of the number of carbon atoms in the long-chain hydrocarbon 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 in the long-chain hydrocarbon group may be within a range that is greater than or greater than any of the lower limits mentioned above; or it may be less than or equal to any of the upper limits mentioned above, while being within a range that is greater than or greater than any of the lower limits mentioned above.

[0083] The lower limit of the number of carbon atoms in the short-chain hydrocarbon group may be approximately 3, 4, 5, 6, 7, or 8, and the upper limit may be approximately 9, 8, 7, or 6. The number of carbon atoms in the short-chain hydrocarbon group may be within or below any of the upper limits mentioned above; or it may be within or below any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above.

[0084] The carbon number may be the total number of carbon atoms present in the long-chain and short-chain hydrocarbon functional groups, or the number of carbon atoms in the linear hydrocarbon chain contained in the functional group. That is, the monovalent hydrocarbon groups present in the long-chain and short-chain hydrocarbon functional groups may have a linear or branched structure, but even in the case of a branched structure, the number of carbon atoms constituting the longest linear chain in that branched structure may be within the range described above. For example, if the branched structure is a 2-ethylhexyl group, the number of carbon atoms constituting the longest linear chain is 6.

[0085] Examples of the long-chain and short-chain hydrocarbon functional groups include one or more selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylcarbonyl groups, and alkylcarbonyl oxy groups. In appropriate examples, the long-chain and short-chain hydrocarbon functional groups may be alkyl groups and / or alkoxy groups.

[0086] The number of carbon atoms present in the alkyl group of 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 or short-chain hydrocarbon functional group (i.e., the number of carbon atoms in the monovalent hydrocarbon group).

[0087] For example, the alkyl group of the alkyl group, alkenyl group, alkynyl group, alkoxy group, alkylcarbonyl group, and alkylcarbonyloxy group may be linear or branched, but in the case of a branched chain, the number of carbon atoms constituting the longest linear chain in that branched chain structure may be within the aforementioned range.

[0088] The hydrocarbon functional group, which is an alkyl group, alkenyl group, alkynyl group, alkoxy group, alkylcarbonyl group, or alkylcarbonyloxy, may optionally be substituted with one or more substituents.

[0089] In the conductive copolymer, the lower limit of the ratio of the total number of moles of the first and second thiophene units relative to the total polymerization units of the conductive copolymer may be approximately 80 mol%, 82 mol%, 84 mol%, 86 mol%, or 88 mol%, and the upper limit may be approximately 99 mol%, 97 mol%, 95 mol%, 93 mol%, 91 mol%, or 90 mol%. The ratio may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any of the lower limits mentioned above.

[0090] The lower limit of the ratio (M2 / M1) of the number of moles of the second thiophene units (M2) to the number of moles of the first thiophene units (M1) in the conductive copolymer may be approximately 0.01, 0.05, 0.1, 0.5, 1, 1.5, or 2, and the upper limit may be approximately 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.8, 0.7, 0.6, or 0.55. The ratio may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being within a range of any lower limit or more than any of the lower limits mentioned above.

[0091] Under these ratios, the conductive copolymer or the polymer layer exhibits an appropriate PTC (Positive Temperature Coefficient) effect, and its surface properties can be adjusted to ensure excellent adhesion to the electrode or current collector for the electrode.

[0092] The hydrocarbon group is a functional group that can impart appropriate fluidity (mobility) to the polymerization process of the conductive polymer or to the conductive polymer itself. Such a functional group imparts appropriate fluidity to the monomer mixture and allows it to diffuse within the monomer mixture, enabling polymerization to occur with excellent efficiency. Furthermore, the conductive polymer having the functional group allows for the stable and uniform formation of the polymer layer between the current collector body and the active material layer through appropriate fluidity.

[0093] Furthermore, the hydrocarbon groups may be appropriately oriented during the drying or annealing process (heat treatment process) applied in the polymer layer formation process to impart PTC effect and oxidation potential characteristics suitable for the copolymer.

[0094] When a certain amount of thermal energy is applied to the hydrocarbon group, it vibrates due to the heat. This vibration (thermal vibration) promotes the dedoping of anions bonded to the copolymer, thereby inducing an increase in resistance. The temperature at which the thermal vibration occurs can be controlled by the length and / or amount of the hydrocarbon group. For example, at the same temperature, the thermal vibration of a relatively long chain is greater than that of a relatively short chain, and consequently, the longer chain can induce a resistance increase effect at a relatively lower temperature. Therefore, the desired PTC effect can be set by controlling the length and / or ratio of the long-chain hydrocarbon group.

[0095] As one example, the first thiophene unit can be represented by the following chemical formula 1.

[0096] [ka]

[0097] In chemical formula 1, R1 and R2 can each be independently hydrogen or the long-chain hydrocarbon group. In such cases, one or more of R1 and R2 can be the long-chain hydrocarbon group.

[0098] In other examples, R1 and R2 can be linked together to form a divalent functional group of the following chemical formula 2.

[0099] [ka]

[0100] In chemical formula 2, L1 and L2 are independently a single bond, an alkylene group, or an alkylidene group, and R3 and R4 are independently hydrogen or the long-chain hydrocarbon group, although one or more of R3 and R4 may be the long-chain hydrocarbon group.

[0101] The specific details regarding long-chain hydrocarbon groups are as described above.

[0102] In this specification, the term "alkylene group" refers to a divalent functional group formed in an alkane by the removal of hydrogen atoms from two different carbon atoms, and the term "alkylidene group" refers to a divalent functional group formed in an alkane by the removal of two hydrogen atoms from one carbon atom.

[0103] In this specification, the term "alkylene group" may refer to an alkylene 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, unless otherwise specified. The alkylene group may be linear, branched, or cyclic, and may be optionally substituted with one or more substituents.

[0104] In this specification, the term "alkylidene group" may refer to 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, unless otherwise specified. The alkylidene group may be linear, branched, or cyclic, and may be optionally substituted with one or more substituents.

[0105] On the other hand, the second thiophene unit can be represented by the following chemical formula 3.

[0106] [ka]

[0107] In chemical formula 3, R5 and R6 can each be independently hydrogen or the short-chain hydrocarbon group, and in such cases, one or more of R5 and R6 can be the short-chain hydrocarbon group.

[0108] In other examples, R5 and R6 can be linked together to form a divalent functional group of the following chemical formula 4.

[0109] [ka]

[0110] In chemical formula 4, L3 and L4 are independently a single bond, an alkylene group, or an alkylidene group, and R7 and R8 are independently hydrogen or the short-chain hydrocarbon group, although one or more of R7 and R8 are the short-chain hydrocarbon group.

[0111] The specific details regarding the aforementioned short-chain hydrocarbon groups are as described above.

[0112] The specific details regarding the alkylene group and alkylidene group in chemical formula 4 are as described in chemical formulas 2 and 3 above.

[0113] The conductive polymer may contain additional units as needed along with the aforementioned units.

[0114] For example, the conductive polymer may additionally contain thiophene units having polar functional groups (hereinafter referred to as third thiophene units).

[0115] In this specification, the term “polar functional group” refers to a functional group containing one or more polar atoms, such as oxygen and / or nitrogen. Examples of such polar functional groups include, but are not limited to, carboxyl groups, hydroxyl groups, amino groups, cyano groups, nitro groups, ether groups, or the functional group of chemical formula 5 below.

[0116] [ka]

[0117] In chemical formula 5, L4 is a single bond, an alkylene group, or an alkylidene group; L3 is an alkylene group or an alkylidene group; R5 is hydrogen or an alkyl group; and n is any number.

[0118] In chemical formula 5, the fact that L4 is a single bond means that L4 does not exist, and the oxygen atom between L4 and L3 is linked to the monomer or polymer backbone.

[0119] The specific examples of alkylene or alkylidene groups in chemical formula 5 are the same as in chemical formulas 2-4.

[0120] The alkyl group R5 in chemical formula 5 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, or it may be a methyl group or an ethyl group. The alkyl group may be linear, branched, or cyclic, and may appropriately be linear or branched.

[0121] In chemical formula 5, the lower limit of n may be approximately 1, 2, 3, or 4, and its upper limit may be approximately 10, 9, 8, 7, 6, 5, 4, or 3. The n may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or greater than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or greater than any of the lower limits mentioned above.

[0122] Through the application of the aforementioned polar functional groups, a polymer layer containing a conductive polymer can be bonded to other layers with appropriate bonding force, thereby uniformly forming such a conductive polymer layer and efficiently achieving the desired protective function.

[0123] The third thiophene unit can be represented, for example, by the following chemical formula 6.

[0124] [ka]

[0125] R in chemical formula 6 10 and R 11 Each can independently be hydrogen or the polar functional group, in this case R 10 and R 11 One or more of these are the aforementioned polar functional groups.

[0126] In other examples, R of chemical formula 6 10 and R 11 These can be linked together to form a divalent functional group of the following chemical formula 7.

[0127] [ka]

[0128] In chemical formula 7, L7 and L8 are independently a single bond, an alkylene group, or an alkylidene group, and R 12 and R 13Although each is independently a hydrogen atom or a polar functional group, R 12 and R 13 One or more of these are the aforementioned polar functional groups.

[0129] The specific details regarding the aforementioned polar functional groups are as described above.

[0130] Furthermore, the specific details regarding the alkylene group or alkylidene group are as described in chemical formulas 2 to 5 above.

[0131] When the third thiophene unit is present in the conductive copolymer, the third thiophene unit can be present such that the total number of moles of the first and second thiophene units is within a predetermined range per mole of the third thiophene unit.

[0132] For example, the lower limit of the total number of moles of the first and second thiophene units per mole of the third thiophene unit may be around 1 mole, 2 moles, 3 moles, 4 moles, 5 moles, 6 moles, 8 moles, or 8.5 moles, and the upper limit may be around 500 moles, 450 moles, 400 moles, 350 moles, 300 moles, 250 moles, 200 moles, 150 moles, 100 moles, 95 moles, 90 moles, 85 moles, 80 moles, 75 moles, 70 moles, 65 moles, 60 moles, 55 moles, 50 moles, 45 moles, 40 moles, 35 moles, 30 moles, 25 moles, 20 moles, 15 moles, 10 moles, 9.5 moles, or 9 moles. The ratio may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or greater than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, but within a range of any lower limit or greater than any of the lower limits mentioned above.

[0133] When the conductive polymer contains the first to third thiophene units, the lower limit of the ratio of the total number of moles of the thiophene units (total number of moles of the first to third thiophene units) to the total number of moles of monomer units in the conductive polymer may be approximately 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, or 95 mol%, and the upper limit may be approximately 100 mol%, 95 mol%, or 90 mol%. The ratio may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any of the lower limits mentioned above.

[0134] The conductive polymer may contain additional polymerization units, as long as it contains the aforementioned units in the aforementioned proportions.

[0135] The polymer layer contains the conductive polymer, and as a result, it can exhibit the properties described above.

[0136] The polymer layer may also contain any additional components, as long as it contains the conductive polymer.

[0137] The thickness of the polymer layer can be appropriately controlled depending on the purpose. For example, the lower limit of the thickness may be around 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, or 500 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, 400 nm, 350 nm, or 300 nm. The thickness may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above.

[0138] The aforementioned thickness can be measured by the method described in "3. Thickness Measurement" of the Examples section of this specification.

[0139] The polymer layer exhibits the characteristics described above, thereby enabling it to exhibit appropriate surface properties, and consequently, excellent adhesion between each layer can be ensured in the electrode or current collector for the electrode.

[0140] For example, the surface energy of the polymer layer can be controlled within a predetermined range using the current collector for the electrode. For example, the lower limit of the surface energy may be around 25 mN / m, 30 mN / m, 35 mN / m, 40 mN / m, or 45 mN / m, and the upper limit may be around 100 mN / m, 95 mN / m, 90 mN / m, 85 mN / m, 80 mN / m, 75 mN / m, 70 mN / m, 65 mN / m, 60 mN / m, 55 mN / m, 50 mN / m, 45 mN / m, 40 mN / m, or 35 mN / m. The surface energy may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or above any of the lower limits mentioned above.

[0141] The aforementioned surface energy can be measured by the method described in "12. Surface Energy Evaluation Method" of the Examples section of this specification.

[0142] This specification also discloses a method for manufacturing the current collector or electrode for the electrode.

[0143] The method for manufacturing a current collector for an electrode of the present invention may include the step of forming the polymer layer on the current collector body, and the method for manufacturing the electrode may include the step of forming the active material layer on the polymer layer.

[0144] There are no particular restrictions on the method of forming the polymer layer on the current collector body. For example, the polymer layer can be formed by diluting the conductive polymer and, if necessary, other additives in a suitable solvent to produce a coating solution, coating the current collector with this solution, and then drying it.

[0145] In another example, the monomers forming the conductive polymer may be directly polymerized on the current collector body to form the polymer layer.

[0146] The method for producing the coating composition for forming the polymer layer and the coating method are not particularly limited, and known coating methods can be applied. Similarly, the method for polymerizing the conductive polymer is not particularly limited, and known methods can be applied. For example, methods utilizing oxidative polymerization reactions and radical reactions are known for producing polythiophene, and such methods can also be applied to the process of forming the conductive polymer in the present invention.

[0147] A polymer layer can be formed on the current collector body using the manufactured coating composition. This process typically includes the steps of coating the current collector body with the coating composition and heat-treating the coated coating composition. The properties of the polymer layer can also be controlled by the conditions of the heat treatment during this process.

[0148] For example, the temperature T and / or time H of the heat treatment can be adjusted.

[0149] For example, the lower limit of the temperature T could 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 its upper limit could be 300°C, 295°C, 290°C, 285°C, 280°C, 275°C, 270°C, 2 The temperature may be approximately 65°C, 260°C, 255°C, 250°C, 245°C, 240°C, 235°C, 230°C, 225°C, 220°C, 215°C, 210°C, 205°C, 200°C, 195°C, 190°C, 185°C, 180°C, 175°C, 170°C, 165°C, 160°C, 155°C, 150°C, 145°C, 140°C, 135°C, or 130°C. The temperature may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, but within a range of any lower limit or more than any of the lower limits mentioned above. Within such a range, the alignment of the hydrocarbon groups of the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0150] To achieve the objective, the product of the heat treatment temperature T and time H (T × H) can be adjusted. For example, the lower limit of the product of the heat treatment temperature T and time H (T × H) is 0.01°C / hour, 0.05°C / hour, 0.1°C / hour, 0.2°C / hour, 0.3°C / hour, 0.5°C / hour, 1°C / hour, 5°C / hour, 10°C / hour, 15°C / hour, 20°C / hour, 25°C / hour, 30°C / hour, 35°C / hour, 40°C / hour, 45°C / hour, 50°C / hour, 75°C / hour, 100°C / hour, 110°C / hour, 120°C / hour, or 130°C / hour. It is possible to reach temperatures of our magnitude, with upper limits being 100,000°C / hour, 95,000°C / hour, 90,000°C / hour, 85,000°C / hour, 80,000°C / hour, 75,000°C / hour, 70,000°C / hour, 65,000°C / hour, 60,000°C / hour, 55,000°C / hour, 50,000°C / hour, 45,000°C / hour, 40,000°C / hour, 35,000°C / hour, 30,000°C / hour, 25,000°C / hour, 20,000°C / hour, 15,000°C / hour, and 10 000℃.hour, 9500℃.hour, 9000℃.hour, 8500℃.hour, 8000℃.hour, 7500℃.hour, 7000℃.hour, 6500℃.hour, 6000℃.hour, 5500℃.hour, 5000℃.ho ur, 4500℃.hour, 4000℃.hour, 3500℃.hour, 3000℃.hour, 2500℃.hour, 2000℃.hour, 1500℃.hour, 1400℃.hour, 1300℃.hour, 1200℃.hour, 1100℃ .hour, 1000℃.hour, 900℃.hour, 800℃.hour, 700℃.hour, 600℃.hour, 500℃.hour, 400℃.hour, 300℃.hour, 200℃.hour, 100℃.hour, 90℃.hour, 8 It may be about 0°C.hour, 70°C.hour, 60°C.hour, 50°C.hour, 45°C.hour, 40°C.hour, 35°C.hour, 30°C.hour, 25°C.hour, 20°C.hour, 15°C.hour or 10°C.hour.The aforementioned product (T × H) may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or greater than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being within a range of any lower limit or greater than any of the lower limits mentioned above. Within such a range, the alignment of the hydrocarbon groups of the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0151] To more effectively ensure the desired properties, the heat treatment may be carried out in two stages.

[0152] For example, the heat treatment may include a step of primary heat treatment of the coating composition at a first temperature T1 for a first time H1 and a step of secondary heat treatment at a second temperature T2 for a second time H2, where the temperatures T1 and T2 are different from each other, and / or the times H1 and H2 are different from each other.

[0153] For example, the lower limit of the temperature T1 could 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 its upper limit could be 300°C, 295°C, 290°C, 285°C, 280°C, or 275°C. The temperature may be approximately 270°C, 265°C, 260°C, 255°C, 250°C, 245°C, 240°C, 235°C, 230°C, 225°C, 220°C, 215°C, 210°C, 205°C, 200°C, 195°C, 190°C, 185°C, 180°C, 175°C, 170°C, 165°C, 160°C, 155°C, 150°C, 145°C, or 140°C. The temperature may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, but within a range of any lower limit or more than any of the lower limits mentioned above. Within such a range, the alignment of hydrocarbon groups in the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0154] For example, the lower limit of the product of the temperature T1 and time H1 (T1 × H1) in the primary heat treatment could be around 0.01°C / hour, 0.05°C / hour, 0.1°C / hour, 0.2°C / hour or 0.3°C / hour, 1°C / hour, 2°C / hour, 3°C / hour, 4°C / hour, 5°C / hour, 6°C / hour, 7°C / hour, 8°C / hour or 9°C / hour, and its upper limit could be 1000°C / hour, 900°C / hour or 800°C / hour. Our product (T1 × H1) may be approximately 700°C / hour, 600°C / hour, 500°C / hour, 400°C / hour, 300°C / hour, 200°C / hour, 100°C / hour, 90°C / hour, 80°C / hour, 70°C / hour, 60°C / hour, 50°C / hour, 45°C / hour, 40°C / hour, 35°C / hour, 30°C / hour, 25°C / hour, 20°C / hour, 15°C / hour, or 10°C / hour. The product (T1 × H1) may be within the range of any upper limit or less than any of the upper limits mentioned above; or within the range of any lower limit or more than any of the lower limits mentioned above; or within the range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any lower limit or more than any of the lower limits mentioned above. Within such a range, the alignment of hydrocarbon groups in the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0155] For example, the lower limit of the heat treatment temperature T2 for the secondary heat treatment 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, or 130°C, and its upper limit may be 300°C, 295°C, 290°C, 285°C, 280°C, 275°C, 270°C, 2 The temperature may be approximately 65°C, 260°C, 255°C, 250°C, 245°C, 240°C, 235°C, 230°C, 225°C, 220°C, 215°C, 210°C, 205°C, 200°C, 195°C, 190°C, 185°C, 180°C, 175°C, 170°C, 165°C, 160°C, 155°C, 150°C, 145°C, 140°C, 135°C, or 130°C. The temperature may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or more than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, but within a range of any lower limit or more than any of the lower limits mentioned above. Within such a range, the alignment of the hydrocarbon groups of the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0156] The product of the secondary heat treatment temperature T2 and time H2 (T2 × H2) can be adjusted. For example, the lower limit of the product of the heat treatment temperature T and time H (T² × H²) may be around 10°C / hour, 15°C / hour, 20°C / hour, 25°C / hour, 30°C / hour, 35°C / hour, 40°C / hour, 45°C / hour, 50°C / hour, 75°C / hour, 100°C / hour, 110°C / hour, 120°C / hour, or 130°C / hour, and its upper limit may be around 1000°C / hour, 900°C / hour, 800°C / hour, 700°C / hour, 600°C / hour, 500°C / hour, 400°C / hour, 300°C / hour, 200°C / hour, 180°C / hour, 160°C / hour, 150°C / hour, 145°C / hour, 140°C / hour, 135°C / hour, or 130°C / hour. The aforementioned product (T2 × H2) may be within a range of any upper limit or less than any of the upper limits mentioned above; or within a range of any lower limit or greater than any of the lower limits mentioned above; or within a range of any upper limit or less than any of the upper limits mentioned above, while being above or greater than any lower limit or greater than any of the lower limits mentioned above. Within such a range, the alignment of the hydrocarbon groups of the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0157] In the above case, the lower limit of the ratio T1 / T2 between the primary heat treatment temperature T1 and the secondary heat treatment temperature T2 may be approximately 0.1, 0.3, 0.5, 0.7, 0.9, 0.95, 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, or 1.07, and the upper limit may be approximately 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, or 1.1. The ratio T1 / T2 may be within the range of any upper limit or less than any of the upper limits mentioned above; or within the range of any lower limit or more than any of the lower limits mentioned above; or within the range of any upper limit or less than any of the upper limits mentioned above, while being above or more than any of the lower limits mentioned above. Within this range, the alignment of hydrocarbon groups in the conductive copolymer can be appropriately controlled, thereby ensuring the desired properties.

[0158] In the above case, the lower limit of the ratio H2 / H1 between the primary heat treatment time H1 and the secondary heat treatment time H2 may be around 0.5, 1, 3, 5, 7, 9, 10, 11, 12, 13, 14, 14.5, or 15, and the upper limit may be around 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 19, 18, 17, 16, 15.5, or 15. The ratio H2 / H1 may be within the range of any upper limit or less than any of the upper limits mentioned above; or within the range of any lower limit or more than any of the lower limits mentioned above; or within the range of any upper limit or less than any of the upper limits mentioned above, but within the range of any lower limit or more than any of the lower limits mentioned above. Within such a range, the alignment of hydrocarbon groups in the conductive copolymer can be appropriately adjusted, and the desired properties can be ensured accordingly.

[0159] In the manufacturing process, additional post-processing steps, such as a suitable drying step, may be carried out following the coating and / or polymerization process.

[0160] There are no particular restrictions on the method for 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, and then rolling it. Such known methods can also be applied in the present invention.

[0161] By controlling the surface properties of the polymer layer through the process described above, excellent adhesive strength can be ensured.

[0162] For example, the lower limit of the adhesion strength of the active material layer to the polymer layer or current collector layer in the electrode may be around 40gf / 20mm, 50gf / 20mm, 60gf / 20mm, 70gf / 20mm, 80gf / 20mm, 90gf / 20mm, 100gf / 20mm, 110gf / 20mm, 120gf / 20mm, 130gf / 20mm, or 140gf / 20mm, and the upper limit is 500gf / The adhesive strength may be approximately 20 mm, 450 gf / 20 mm, 400 gf / 20 mm, 350 gf / 20 mm, 300 gf / 20 mm, 250 gf / 20 mm, 200 gf / 20 mm, 150 gf / 20 mm, 140 gf / 20 mm, 130 gf / 20 mm, 120 gf / 20 mm, 110 gf / 20 mm, 100 gf / 20 mm, 90 gf / 20 mm, 80 gf / 20 mm, or 70 gf / 20 mm. The adhesive strength may be within a range that is greater than or greater than any of the lower limits mentioned above; or it may be less than or equal to any of the upper limits mentioned above, while being greater than or greater than any of the lower limits mentioned above.

[0163] The aforementioned adhesive strength is described in "11. Method for Evaluating Adhesion Strength" of the Examples section of this specification.

[0164] In the above, the adhesive strength of the active material layer to the polymer layer or current collector layer means the adhesive strength in which, according to the adhesive strength evaluation method described in the examples, phenomena such as the peeling of all or part of the active material layer from the polymer layer, the peeling of all or part of the polymer layer from the current collector layer, and other interfacial fracture phenomena do not occur (adhesive strength B in the evaluation method of the examples).

[0165] The present invention also relates to an electrode assembly or electrochemical element including such electrodes, for example, a secondary battery.

[0166] The electrochemical element may include the electrodes as a positive electrode and / or a negative electrode. As long as the electrodes of the present invention are used as a negative electrode and / or a positive electrode, other configurations and manufacturing methods of the electrochemical element are not particularly limited, and known methods may be applied. [Effects of the Invention]

[0167] This specification discloses current collectors for electrodes and their applications. The current collectors for electrodes exhibit excellent electrical characteristics, including low resistance, under normal conditions such as those of a secondary battery, and can ensure stability under abnormal conditions through increased resistance, etc. This specification also discloses applications of the current collectors for electrodes. [Brief explanation of the drawing]

[0168] [Figure 1] This is an illustrative cross-sectional view of an electrode. [Figure 2] This shows the NMR analysis results for the monomer from Production Example 1. [Modes for carrying out the invention]

[0169] The current collectors and the like disclosed herein will be described in detail below through examples and comparative examples, but the range of current collectors is not limited by the following examples.

[0170] 1.NMR analysis method 1 ¹H-NMR analysis was performed at room temperature (approximately 25°C) using an NMR spectrometer including a Bruker UltraShield spectrometer (300 MHz) with a triple-resonance 5 mm probe. The sample was diluted to a concentration of approximately 10 mg / ml in NMR measurement solvent (CDCl3), and chemical transfers were expressed in ppm.

[0171] 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. Then, the calibration standard sample and the sample to be analyzed were filtered through a syringe filter (pore size: 0.45 μm) and then measured. The analysis program used Empower 3 from Waters. 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).

[0172] The measurement conditions for GPC are as follows.

[0173] <GPC Measurement Conditions> Equipment: 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)

[0174] 3. Thickness measurement The thickness of the polymer layer and other components was measured by cross-sectioning the electrode or current collector using an ion milling device (Hitachi, IM5000) and then capturing an image with a scanning electron microscope (SEM) (JEOL, JSM-7200F). The cross-section formation conditions for ion milling were set to cross-section milling mode, with a speed (reciprocation / min) of 3, an acceleration voltage of 6.0kV, a discharge voltage of 15kV, a current of 150μA, and a time of 4 hours.

[0175] 4. Method for measuring oxidation potential The oxidation potential was measured using the following method. A polymer layer approximately 10 μm thick was formed on an aluminum foil (Al Foil) with a thickness of approximately 15 μm using a conductive copolymer. A coating solution was prepared by dispersing the polymer (conductive copolymer, etc.) to be measured for oxidation potential in a solvent (Chloroform) at a concentration of approximately 2.0% by weight. This coating solution was then coated onto the aluminum foil (Al Foil) using a bar coating method, and the mixture was maintained at 140°C for approximately 4 minutes, and then again at approximately 130°C for approximately 60 minutes to form the polymer layer. Subsequently, a separation membrane and a lithium film were laminated on the polymer layer to produce a laminate consisting of aluminum foil / polymer layer / separation membrane / lithium film, and this laminate was punched out into a circle with a diameter of approximately 1.4 cm. A coin cell was manufactured using the circularly punched laminate and an electrolyte (using the Welcos CR2032 coin cell kit). As the separation membrane, the WL20C model from Doublescope was used, and as the lithium film, a film with a thickness of approximately 100 μm was used. As the electrolyte, a 1M LiPF6 solution from Enchem Corporation was used (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethyl methyl carbonate).

[0176] The oxidation potential of the coin cell was measured at 25°C using an electrochemical instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC) to determine the oxidation potential of lithium and lithium ions (Li / Li). + The measurement was performed using the following as the reference. The oxidation potential was measured under the following conditions: a scan speed of 0.17 mV / sec to 0.5 mV / sec in the range of 1.5 V to 5.5 V, and the oxidation potential was measured by measuring the CV (Cyclic Voltammetry).

[0177] 5.DC resistance measurement method DC resistance was evaluated using the same coin cell that was used for oxidation potential measurement. A voltage of 4.3 eV was applied to the coin cell at room temperature (25°C) for 10 minutes, and the DC resistance was measured using a Fluke digital multimeter (FLUKE-87-5).

[0178] 6. Interfacial resistance (AC impedance resistance) The interfacial resistance was evaluated using EIS (Electrochemical Impedance Spectronization) with the same coin cell used for oxidation potential measurement. A voltage of 4.3V was applied to the coin cell at room temperature (25°C) for 10 minutes, and the interfacial resistance obtained in the high-frequency region of the Nyquist plot obtained by the EIS measurement method at 50,000Hz to 0.1Hz was measured. An electrochemical measuring instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC) was used as the EIS measuring instrument.

[0179] 7. Measurement of maximum resistance change rate (DC resistance) The maximum resistance change rate △R1 is determined by the following equation 1.

[0180] [Formula 1] △R1=Max{(R n+5 / R n ) / 5}

[0181] The aforementioned △R1 ​​is measured using the following method.

[0182] A coin cell for DC resistance measurement (the coin cell used in "5. DC Resistance Measurement Method" above) is placed in the center of a convection oven (JOTECH, OF3-05W), and the oven temperature is set to increase by 5°C per minute from an initial temperature of 25°C to a final temperature of 135°C. The coin cell is connected to an external resistance measuring multimeter (Fluke digital multimeter (FLUKE-87-5)) so that resistance measurement is possible. Subsequently, the DC resistance is measured at each temperature as the temperature increases as set. Specifically, the DC resistance is measured at 25°C, 30°C, 35°C, 40°C, 45°C, 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, and 130°C. Each temperature is maintained for one minute according to the settings, and the DC resistance is measured when one minute has elapsed at that temperature. The DC resistance at each temperature is R in Equation 1. n Therefore, the DC resistance at a temperature 5°C higher than the temperature in question is R in the above formula 1. n+5 The DC resistances measured at 25°C, 30°C, 35°C, 40°C, 45°C, 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, and 125°C are respectively R n As such, 21 values ​​(R) in the temperature range of 25℃ to 130℃ n+5 / R n After calculating ) / 5, the maximum value among them is taken from the above formula 1 Max{(R n+5 / R n Let ) / 5}(=△R1), and the maximum value of (R n+5 / R n The temperature n°C at ) / 5 is defined as the On-Set temperature.

[0183] 8. Measurement of maximum resistance change rate (AC impedance) The maximum resistance change rate △R2 is determined by the following equation 2.

[0184] [Formula 2] △R² = Max{(R z+5 / R z ) / 5}

[0185] The aforementioned △R2 is measured using the following method.

[0186] A coin cell for measuring AC impedance resistance (the coin cell used in "6. Interface Resistance (AC Impedance Resistance)" above) is placed in the center of a convection oven (JOTECH, OF3-05W), and the oven temperature is set to increase by 5°C per minute from an initial temperature of 25°C to a final temperature of 135°C. The coin cell is connected to an external resistance measuring device (the measuring device used in "6. Interface Resistance (AC Impedance Resistance)" above) so that resistance measurement is possible. The temperature is then increased as set, and the AC impedance resistance is measured at each temperature. Specifically, the AC impedance resistance is measured at 25°C, 30°C, 35°C, 40°C, 45°C, 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, and 130°C. Each temperature is maintained for one minute according to the settings, and the AC impedance resistance is measured after one minute has elapsed at that temperature.

[0187] The AC impedance resistance at each temperature is R in Equation 2 above. z Therefore, the AC impedance resistance at a temperature 5°C higher than the temperature in question is R in Equation 2. z+5 The AC impedance resistance measured at 25°C, 30°C, 35°C, 40°C, 45°C, 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, and 125°C is R z As such, 21 values ​​(R) in the temperature range of 25℃ to 130℃z+5 / R z After calculating ) / 5, the maximum value among them is taken from the above equation 2 Max{(R z+5 / R z Let ) / 5}(=△R2), and the maximum value of (R z+5 / R z The temperature z°C at ) / 5 is defined as the On-Set temperature.

[0188] The AC impedance resistor was defined as the resistance obtained as a semicircle in the high-frequency region of the Nyquist plot, which was obtained by applying a voltage of 4.3V for 10 minutes and measuring from 50,000Hz to 0.1Hz using the EIS measurement method.

[0189] 9. Discharge Capacity Measurement The discharge capacity to verify the result of Equation 3 below was evaluated using the following method.

[0190] [Formula 3] △R3 = 100 × (C1 - C2) / C1

[0191] In Equation 3, ΔR3 is the percentage change in discharge capacity, C1 is the discharge capacity at room temperature (approximately 25°C), and C2 is the discharge capacity after storage at 70°C for 60 hours.

[0192] A coin cell (reference capacity: 200 mAh / g) for verifying the discharge capacity of Equation 3 was fabricated using the following method. The coin cell was fabricated using a CR2032 standard coin cell kit (Wellcos CR2032 coin cell kit). When fabricating the coin cell, the electrode fabricated in the example or comparative example was used as the positive electrode, and a lithium film (thickness: 100 μm) was used as the negative electrode. A carbonate-based electrolyte was used, specifically a 1 M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethyl methyl carbonate), and a PE (poly(ethylene)) separation membrane (Double Scope's WL20C model) was used as the separation membrane.

[0193] The coin cell was subjected to one charge / discharge cycle at 25°C, and the capacity at 0.2C was defined as the discharge capacity C1 in Equation 3. One charge / discharge cycle means that the charge termination voltage was set to 4.5V and the charge termination current to 1mA, and the charge was charged at a rate of 0.2C using the CC (Constant Current) / CV (Constant Voltage) method, and the discharge termination voltage was set to 3.0V, and the discharge was performed at a rate of 0.2C using the CC (Constant Current) method. This process was repeated once as one cycle. The discharge capacity after one charge / discharge cycle was applied as the discharge capacity (C1) in Equation 3.

[0194] Immediately after manufacturing the coin cell, the measurement method described above was applied to determine C1. Then, after storing the coin cell at 70°C for 60 hours, the discharge capacity was measured using the same method, and this value was applied as C2 in Equation 3.

[0195] 10. Discharge Capacity Measurement The discharge capacity to verify the result of Equation 4 below was evaluated using the following method.

[0196] [Formula 4] △R4 = 100 × (C1 - C3) / C1

[0197] In Equation 4, ΔR4 is the percentage change in discharge capacity, C1 is the discharge capacity at room temperature (approximately 25°C), and C3 is the discharge capacity after storage at 70°C for 60 hours followed by storage at 130°C for 10 minutes.

[0198] The coin cell used to verify the discharge capacity in Equation 4 was the same one used in "9. Discharge Capacity Measurement" above. C1 in Equation 4 was measured using the same method as C1 in "9. Discharge Capacity Measurement" above.

[0199] Subsequently, the coin cell was stored at 70°C for 60 hours, then again at 130°C for 10 minutes, after which the discharge capacity C3 was determined. C3 was determined using the following method: The charge termination voltage was set to 4.5V and the charge termination current to 1mA, and the cell was charged at a rate of 0.5C using the CC (Constant Current) / CV (Constant Voltage) method. Then, the discharge termination voltage was set to 3.0V, and the cell was discharged at a rate of 2C using the CC (Constant Current) method. This process constituted one cycle, and the above cycle was repeated 30 times. The discharge capacity after 30 charge / discharge cycles was applied as C3 in Equation 4. The 30 charge / discharge cycles were carried out at 45°C.

[0200] 11. Method for evaluating adhesive strength The adhesive strength was measured using a TA analyzer (TAXTplusC) according to a known method for measuring the adhesive strength of the active material layer. The test specimens were cut to a width of approximately 20 mm and the adhesive strength was evaluated. The test specimens used were laminates in which a polymer layer was formed on a current collector (adhesion strength A) and final electrodes in which an active material layer was formed on the polymer layer (adhesion strength B), as described in the examples or comparative examples below. That is, adhesive strength A is the adhesive strength of the polymer layer to the current collector, and adhesive strength B is the adhesive strength of the active material layer to the polymer layer or the current collector layer. During adhesive strength measurement, the peeling angle was set to 90 degrees and the peeling speed to approximately 5 mm / sec. After measurement, the portion where the peak stabilized was averaged and defined as the adhesive strength.

[0201] 12. Surface energy evaluation method The surface energy was evaluated using a Kruss measuring instrument (DSA 100), and the contact angle was evaluated using water and diiodomethane, thereby determining the surface energy.

[0202] Manufacturing Example 1. Synthesis of Monomer (A) The monomer of chemical formula A below was synthesized by the following method.

[0203] [ka]

[0204] In chemical formula A, n is 3.

[0205] 3 g (26.28 mmol, 1 eq) of 3-methoxythiophene and 7.03 g (39.42 mmol, 1.5 eq) of triethylene glycol monomethyl ether were dissolved in 150 ml of toluene with 500 mg of p-toluenesulfonic acid (p-TsOH) (2.63 mmol, 0.1 eq) and mixed. The mixture was reacted under reflux at 120°C under a nitrogen atmosphere, and methanol produced by the reaction (transetherification) was removed with a charged 4A type molecule in a soxhlet extractor. After refluxing the reaction mixture for 24 hours, it was cooled to room temperature, 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 for the target compound (monomer (A)) are shown in Figure 2.

[0206] Example 1. Synthesis of polythiophene (A) Polythiophene (A) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride, then adding 1 g (3.94 mmol, 0.6 eq) of 3-dodecylthiophene, 0.33 g (1.97 mmol, 0.3 eq) of 3-hexylthiophene, and 0.16 g (0.66 mmol, 0.1 eq) of monomer (A) from Production Example 1. Polymerization was carried out at 30°C for 24 hours to produce polythiophene (A).

[0207] 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 solvent to remove unreacted iron(III) chloride, monomers, and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (A).

[0208] Polythiophene (A) had a weight-average molecular weight (Mw) and a number-average molecular weight (Mn) of 118,000 g / mol and 24,500 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0209] Electrode manufacturing An aluminum foil with a thickness of approximately 15 μm was used as the current collector body. The manufactured polythiophene (A) was dispersed in a solvent (Chloroform) at a concentration of approximately 2.0% by weight to produce a coating solution. The coating solution was coated onto the current collector body using a bar coating method, maintained at 140°C for approximately 4 minutes, and then maintained again at approximately 130°C for approximately 60 minutes to form the polymer layer (thickness: approximately 300 nm). An active material layer was formed on the polymer layer to produce an electrode. The active material layer was formed by applying a slurry containing lithium cobalt oxide (LiCoO2), carbon-based conductive material (ECP (Ketjen Black) 0.5%, SFG (Trimrex graphite) 0.4%, DB (Denka Black) 0.4%), PVDF (polyvinylidene fluoride), and NMP (N-Methyl-2-pyrrolidone) in a weight ratio of 75:1:1:23 (LiCoO2: conductive material:PVDF:NMP) to the polymer layer to a thickness of approximately 90 μm using a doctor blade. After drying at room temperature (approximately 25°C), it was further dried under vacuum conditions at 120°C and rolled to a porosity of approximately 25%.

[0210] Example 2. Synthesis of polythiophene (B) Polythiophene (B) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride, then adding 0.5 g (1.97 mmol, 0.3 eq) of 3-dodecylthiophene, 0.66 g (3.94 mmol, 0.6 eq) of 3-hexylthiophene, and 0.16 g (0.66 mmol, 0.1 eq) of monomer (A) from Production Example 1, and polymerizing at 30°C for 24 hours.

[0211] 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 solvent to remove unreacted iron(III) chloride monomers and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (B).

[0212] Polythiophene (B) had a weight-average molecular weight (Mw) and a number-average molecular weight (Mn) of 105,000 g / mol and 22,300 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0213] Electrode manufacturing The electrode was manufactured in the same manner as in Example 1, except that polythiophene (B) was used instead of polythiophene (A). In this case, the thickness of the polymer layer was approximately 300 nm.

[0214] Example 3. Synthesis of polythiophene (C) Polythiophene (C) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride, then adding 0.88 g (3.94 mmol, 0.6 eq) of 3-decylthiophene, 0.33 g (1.97 mmol, 0.3 eq) of 3-hexylthiophene, and 0.16 g (0.66 mmol, 0.1 eq) of monomer (A) from Production Example 1. Polymerization was carried out at 30°C for 24 hours to produce polythiophene (C). 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(III) chloride monomers and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (C).

[0215] Polythiophene (C) had a weight-average molecular weight (Mw) of 110,500 g / mol and a number-average molecular weight (Mn) of 23,400 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0216] Electrode manufacturing The electrode was manufactured in the same manner as in Example 1, except that polythiophene (C) was used instead of polythiophene (A). In this case, the thickness of the polymer layer was approximately 300 nm.

[0217] Example 4. Synthesis of polythiophene (D) Polythiophene (D) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride, then adding 1 g (3.94 mmol, 0.6 eq) of 3-dodecylthiophene, 0.39 g (1.97 mmol, 0.3 eq) of 3-octylthiophene, and 0.16 g (0.66 mmol, 0.1 eq) of monomer (A) from Production Example 1. Polymerization was carried out at 30°C for 24 hours to produce polythiophene (D). 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(III) chloride monomers and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (D).

[0218] Polythiophene (D) had a weight-average molecular weight (Mw) and number-average molecular weight (Mn) of 136,000 g / mol and 28,000 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0219] Electrode manufacturing The electrode was manufactured in the same manner as in Example 1, except that polythiophene (D) was used instead of polythiophene (A). In this case, the thickness of the polymer layer was approximately 300 nm.

[0220] Example 5. A coating solution was prepared by dispersing the polythiophene (A) obtained in Example 1 in a solvent (Chloroform) at a concentration of approximately 2% by weight. An electrode was manufactured in the same manner as in Example 1, except that the coating solution was coated onto the current collector body using a bar coating method and maintained at 90°C for about 20 minutes to form a polymer layer with a thickness of approximately 300 nm.

[0221] Comparative Example 1. Synthesis of polythiophene (E) Polythiophene (E) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride and adding 1.66 g (6.57 mmol, 1 eq) of 3-dodecylthiophene to the solution and polymerizing at 30°C for 24 hours. 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(III) chloride monomers and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (E).

[0222] Polythiophene (E) had a weight-average molecular weight (Mw) and number-average molecular weight (Mn) of 138,000 g / mol and 29,500 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0223] Electrode manufacturing The electrode was manufactured in the same manner as in Example 1, except that polythiophene (E) was used instead of polythiophene (A). In this case, the thickness of the polymer layer was approximately 300 nm.

[0224] Comparative Example 2. Synthesis of polythiophene (F) Polythiophene (F) was prepared by dissolving 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride in 150 ml of methylene chloride and adding 1.1 g (6.54 mmol, 1 eq) of 3-hexylthiophene to the solution and polymerizing it at 25°C for 24 hours. 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(III) chloride monomers and low molecular weight oligomers. The residue precipitated inside the permeable membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (F).

[0225] Polythiophene (F) had a weight-average molecular weight (Mw) and number-average molecular weight (Mn) of 94,000 g / mol and 21,500 g / mol, respectively, and an oxidation potential of approximately 3.7 V.

[0226] Electrode manufacturing The electrode was manufactured in the same manner as in Example 1, except that polythiophene (F) was used instead of polythiophene (A). In this case, the thickness of the polymer layer was approximately 300 nm.

[0227] Comparative Example 3. The electrode was manufactured in the same manner as in Example 1, except that a polymer layer was not formed.

[0228] The measurement results for the manufactured electrodes are summarized in Tables 1 and 2 below. In Tables 1 and 2 below, C in Equation 3 1と In Equation 4, C1 should theoretically show the same value, but in actual experiments, some differences occurred within the margin of error. In Tables 1 and 2 below, the surface energy is the surface energy of the polymer layer in each example or comparative example, and is the surface energy of the surface of the polymer layer on which the active material layer is formed.

[0229] In Tables 1 and 2, the unit for △R1 is Ω.cm / ℃, and the unit for △R2 is Ω / ℃.

[0230] [Table 1]

[0231] [Table 2] [Explanation of symbols]

[0232] 100: Current collector body 200: Polymer layer 300: Active material layer

Claims

1. The current collector body includes, and a polymer layer formed on the current collector body. The polymer layer comprises a copolymer containing a first thiophene unit having a hydrocarbon group having 10 or more carbon atoms and a second thiophene unit having a hydrocarbon group having 9 or fewer carbon atoms. Current collector for electrodes where ΔR1 in Equation 1 below is 100 or more: [Formula 1] △R1=Max {(R n+5 / R n ) / 5} In Equation 1, R n is the DC resistance at any temperature n°C within the range of 25°C to 135°C, R n+5 is the DC resistance at a temperature (n+5)°C which is 5°C higher than the aforementioned temperature n°C, and Max {(R n+5 / R n) / 5} is the maximum value among the values ​​expressed as (R n+5 / R n) / 5 confirmed within the temperature range of 25°C to 135°C.

2. The electrode current collector according to claim 1, wherein the hydrocarbon group is a linear or branched alkyl group, an alkenyl group, or an alkynyl group.

3. The electrode current collector according to claim 1, wherein the number of carbon atoms in the hydrocarbon group of the first thiophene unit is in the range of 10 to 20, and the number of carbon atoms in the hydrocarbon group of the second thiophene unit is in the range of 3 to 9.

4. The electrode current collector according to claim 1, wherein the copolymer contains 80 mol% or more of thiophene units having hydrocarbon groups with 10 or more carbon atoms and thiophene units having hydrocarbon groups with 9 or fewer carbon atoms.

5. The electrode current collector according to claim 1, wherein the ratio M2 / M1 of the number of moles M2 of the second thiophene units to the number of moles M1 of the first thiophene units is in the range of 0.01 to 100.

6. The electrode current collector according to claim 1, wherein the first thiophene unit is represented by the following chemical formula 1, and the second thiophene unit is represented by the following chemical formula 3: 【Chemistry 1】 R in chemical formula 1 １ and R ２ Each is independently a hydrogen atom or a hydrocarbon group having 10 or more carbon atoms, however R １ and R ２ One or more of them are the hydrocarbon group having 10 or more carbon atoms, or R １ and R ２ These are linked together to form a divalent functional group of the following chemical formula 2: 【Chemistry 2】 L in Chemical Formula 2 １ and L ２ are each independently a single bond, an alkylene group or an alkylidene group, R ３ and R ４ are each independently hydrogen or a hydrocarbon group having 10 or more carbon atoms, provided that one or more of R ３ and R ４ are a hydrocarbon group having 10 or more carbon atoms: 【Transformation 3】 R in chemical formula 3 ５ and R ６ Each is independently a hydrogen atom or a hydrocarbon group with 9 or fewer carbon atoms, however R ５ and R ６ One or more of them are hydrocarbon groups having 9 or fewer carbon atoms, or R ５ and R ６ These are linked together to form a divalent functional group of the following chemical formula 4: 【Chemistry 4】 L in chemical formula 4 ３ and L ４ Each of these is independently a single bond, an alkylene group, or an alkylidene group, and R ７ and R ８ Each is independently either hydrogen or a hydrocarbon group having 9 or fewer carbon atoms, however R ７ and R ８ One or more of these is a hydrocarbon group having 9 or fewer carbon atoms.

7. The electrode current collector according to claim 1, wherein the copolymer further comprises a third thiophene unit having a polar functional group.

8. The electrode current collector according to claim 7, wherein the polar functional group is a carboxyl group, a hydroxyl group, an amino group, a cyano group, a nitro group, an ether group, or a functional group of the following chemical formula 5: 【Transformation 5】 L in chemical formula 5 ４ L is a single bond, an alkylene group, or an alkylidene group. ３ R is an alkylene group or alkylidene group, ５ is a hydrogen atom or an alkyl group, and n is a number in the range of 1 to 10.

9. The current collector for electrodes according to claim 7, wherein the third thiophene unit is represented by the following chemical formula 6: 【Transformation 6】 R in chemical formula 6 １０ and R １１ Each is independently a hydrogen atom or a polar functional group, however R １０ and R １１ One or more of them are the aforementioned polar functional groups, or R １０ and R １１ These are linked together to form a divalent functional group of the following chemical formula 7: 【Transformation 7】 L in chemical formula 7 ７ and L ８ Each of these is independently a single bond, an alkylene group, or an alkylidene group, and R １２ and R １３ Each is independently either hydrogen or the aforementioned polar functional group, however R １２ and R １３ One or more of these are the aforementioned polar functional groups.

10. The electrode current collector according to claim 7, wherein the copolymer contains a third thiophene unit in an amount such that there are 1 to 500 moles of first and second thiophene units per mole of the third thiophene unit.

11. △R1 is confirmed R ｎ The electrode current collector according to claim 1, wherein the temperature exceeds 80°C.

12. The electrode current collector according to claim 1, wherein ΔR2 in the following equation 2 is 10 or more: [Formula 2] △R2=Max{(R ｚ＋５ / R ｚ ) / 5} In equation 2, R ｚ R is the AC impedance resistance at any temperature n°C within the range of 25°C to 135°C. ｚ＋５ This is the AC impedance resistance at a temperature (n+5)°C, which is 5°C higher than the aforementioned temperature n°C, and Max { (R ｚ＋５ / R ｚ ) / 5} was confirmed within the temperature range of 25°C to 135°C (R ｚ＋５ / R ｚ It is the maximum value among those expressed as ) / 5.

13. △R2 is confirmed R ｚ The electrode current collector according to claim 12, wherein the temperature is 80°C or higher.

14. The electrode current collector according to claim 1, wherein the absolute value of △R3 in the following equation 3 is less than 10%: [Formula 3] △R3=100×(C １ -C ２ ) / C １ In equation 3, C １ This is the discharge capacity at 25°C, C ２ This is the discharge capacity after being maintained at 70°C for 60 hours.

15. The electrode current collector according to claim 1, wherein the absolute value of △R4 in the following equation 4 is 15% or more: [Formula 4] △R4=100×(C １ -C ３ ) / C １ In equation 4, C １ This is the discharge capacity at 25°C, C ３ This is the discharge capacity after being maintained at 130°C for 10 minutes.

16. The electrode current collector according to claim 1, wherein the polymer layer has a thickness in the range of 10 nm to 2 μm.

17. Current collector for electrodes as described in any one of claims 1 to 16; and An electrode comprising an active material layer formed on the polymer layer of the current collector.

18. An electrode assembly comprising the electrode described in claim 17.

19. A secondary battery comprising the electrode described in claim 17.

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