current collector

Abstract

This specification discloses a current collector. The current collector includes a current collector body and a polymer layer formed on the current collector body, and the polymer layer can include a conductive polymer and a conductive material. The current collector exhibits excellent electrical properties, including low resistance, under normal conditions and can ensure stability through increased resistance under abnormal conditions. This specification also discloses uses of the current collector.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0135139, dated October 19, 2022, the entire contents of which are incorporated herein by reference.

[0002] This specification discloses a current collector and its uses. [Background technology]

[0003] Energy storage technology is finding applications in a wide range of devices, including 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 times become longer, development of secondary batteries with high energy density, working potential, long cycle life, and low self-discharge rate is progressing.

[0005] As major developed countries curb the production of internal combustion engine vehicles to combat global warming and air pollution, major automakers are also developing a variety of electric vehicles, and the importance of secondary batteries, which have high energy density, high discharge voltage, and output stability as the driving source for these vehicles, is becoming increasingly important.

[0006] However, in accordance with this trend, the frequency of fires or explosions caused by overcharging, exposure to high temperatures, external impacts, etc., is also increasing in devices and automobiles that use secondary batteries as their energy source.

[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 an external stimulus.When a secondary battery is overcharged, exposed to high temperatures, or exposed to external stimuli, the short circuit can occur due to the contraction of the separator caused by an increase in the internal temperature of the secondary battery, or the destruction of the internal structure of the secondary battery due to an external impact.

[0008] When a short circuit occurs, the movement of lithium ions and electrons can be concentrated at the point where the positive and negative electrodes are in direct contact, which can accelerate internal heat generation, generating gases inside the battery and causing it to expand in volume, increasing the risk of fire. Summary of the Invention [Problem to be solved by the invention]

[0009] This specification discloses a current collector and its uses. The purpose of this specification is to disclose a current collector that exhibits excellent electrical properties, including low resistance, under normal conditions and ensures stability through increased resistance under abnormal conditions. The purpose of this specification is to disclose uses of the current collector. [Means for solving the problem]

[0010] As used herein, the term "room temperature" means a natural temperature that is neither heated nor cooled, and may be, for example, any temperature within the range of 10°C to 30°C, or a temperature of about 23°C or about 25°C.

[0011] In the present specification, when the temperature at which a physical property is measured affects the physical property, the physical property is measured at room temperature unless otherwise specified.

[0012] Unless otherwise specified, temperatures are given in degrees Celsius (°C) herein.

[0013] As used herein, the term "normal pressure" refers to natural pressure without pressure or decompression, and typically refers to a pressure of about 730 mmHg to 790 mmHg. When the measurement pressure affects a physical property mentioned in this specification, the physical property is measured at normal pressure unless otherwise specified.

[0014] When the humidity at which a physical property is measured affects the results of the physical property referred to in this specification, the physical property is measured at standard humidity unless otherwise specified.

[0015] Humidity under standard conditions means any relative humidity within a range of 40% to 60%, for example, a relative humidity of about 55% or 60%.

[0016] As used herein, the term "normal state" refers to a normal operating state of a secondary battery (for example, a normal charging or discharging state of a secondary battery) or a storage state.

[0017] As used herein, the term "abnormal condition" refers to a dangerous condition in which an abnormal charge flow, abnormal heat generation, or explosion occurs due to an external impact and / or short circuit, or in which the likelihood of such an abnormal condition occurring is increased.

[0018] The present specification discloses a current collector, which may be a current collector for an electrode.

[0019] The current collector may include a current collector body and a polymer layer formed on the body. The current collector may be used to form an electrode. For example, an electrode formed using the current collector may include the current collector and an active material layer formed on the polymer layer of the current collector. Figure 1 illustrates an electrode in which an active material layer 300 is formed on the polymer layer 200 of a current collector including the current collector body 100 and polymer layer 200.

[0020] In the current collector or electrode, the current collector body 100 and the polymer layer 200, and the polymer layer 200 and the active material layer 300 may be in contact with each other, or other elements may be present between them. In addition, although the drawings show 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, two layers of polymer layer 200 may be present 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 one layer may be present between either of the active material layers 300 present on both sides and the current collector body 100.

[0021] The electrode formed of the current collector may be an anode or a cathode applied to a secondary battery.

[0022] The polymer layer in the current collector or electrode is a layer that can variably control the movement of charges through the electrode depending on the temperature.

[0023] By applying the polymer layer, the collector or electrode or an electrochemical device such as a secondary battery to which the polymer layer is applied exhibits stable and improved performance under normal conditions, and can ensure stability through an increase in resistance under abnormal conditions.

[0024] In one example, the upper limit of the DC resistance of the polymer layer, current collector or electrode at 25°C is 10,000 Ω·cm, 9500 Ω·cm, 9000 Ω·cm, 8500 Ω·cm, 8000 Ω·cm, 7500 Ω·cm, 7000 Ω·cm, 6500 Ω·cm, 6000 Ω·cm, 5500 Ω·cm, 5000 Ω·cm, 4500 Ω·cm, 4000 Ω·cm, 3500 Ω·cm, 3000 Ω·cm, 2500 Ω·cm, 2000 Ω·cm, 1500 Ω·cm, 1000 Ω·cm, 950 Ω·cm, 900 Ω·cm, 850 Ω·cm, 800 Ω·cm, 750 Ω·cm, 700 Ω·cm, 650 Ω·cm, 600 Ω·cm, 550 Ω·cm, 500 Ω·cm, 450 Ω·cm, 400 Ω·cm, or 350 Ω·cm, with a lower limit of about 10 Ω·cm, 50 Ω·cm, 100 Ω·cm, 150 Ω·cm, 200 Ω·cm, 250 Ω·cm, 300 Ω·cm, 350 Ω·cm, 400 Ω·cm, 450 Ω·cm, 500 Ω·cm, 550 Ω·cm, or 600 Ω·cm. The DC resistivity may range up to or below any of the aforementioned upper limits; or may range up to or below any of the aforementioned upper limits but up to or above any of the aforementioned lower limits.

[0025] The DC resistance can be measured for a coin cell to which the polymer layer is applied. The coin cell can be manufactured by forming the polymer layer to a thickness of about 200 nm on aluminum foil (Al foil) with a thickness of about 15 μm, laminating this with a separator and a lithium film to manufacture an aluminum foil / polymer layer / separator / lithium film laminate, and then punching the laminate into a circle with a diameter of about 1.4 cm. The coin cell can be manufactured using a Welcos CR2032 coin cell kit and the punched laminate and electrolyte. The separator may be a WL20C model from Double Scope Korea, the lithium film may be a film with a thickness of about 100 μm, and the electrolyte may be a 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate) from Enchem. A voltage of 4.3 eV is applied to the coin cell at room temperature (25°C) for 10 minutes, and the DC resistance is measured using a Fluke digital multitester (FLUKE-87-5).

[0026] The upper limit of the AC impedance resistance of the polymer layer, current collector, or electrode may be about 1,000Ω, 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, and the lower limit may be about 10Ω, 15Ω, 20Ω, 25Ω, 30Ω, 35Ω, 40Ω, 45Ω, 50Ω, 55Ω, 60Ω, 65Ω, 70Ω, 75Ω, 80Ω, or 85Ω. The AC impedance resistance may range up to or below any of the aforementioned upper limits; or may range up to or below any of the aforementioned upper limits, but up to or above or exceeding any of the aforementioned lower limits.

[0027] The AC impedance resistance can be measured by applying a voltage of 4.3 V for 10 minutes at room temperature (25°C) to the same coin cell used to measure the DC resistance, and measuring the interfacial resistance in the high frequency region of the Nyquist plot obtained by EIS measurement at 50,000 Hz to 0.1 Hz. A potentiostat (Princeton Applied Research, PARASTAT-MC) can be used as the EIS measurement device.

[0028] The upper limit of the EIS conductivity of the polymer layer, current collector, or electrode may be about 1,000 Ω, 950 Ω, 900 Ω, 850 Ω, 800 Ω, 750 Ω, 700 Ω, 650 Ω, 600 Ω, 550 Ω, 500 Ω, 450 Ω, 400 Ω, 350 Ω, 300 Ω, 250 Ω, 200 Ω, 150 Ω, 100 Ω, 95 Ω, 90 Ω, 85 Ω, 80 Ω, 75 Ω, 70 Ω, 65 Ω, 60 Ω, 55 Ω, or 50 Ω, and the lower limit may be about 10 Ω, 15 Ω, 20 Ω, 25 Ω, 30 Ω, 35 Ω, 40 Ω, 45 Ω, 50 Ω, 55 Ω, 60 Ω, 65 Ω, 70 Ω, 75 Ω, 80 Ω, or 85 Ω. The EIS conductivity may be within a range equal to or less than any of the upper limits mentioned above; or may be within a range equal to or less than any of the upper limits mentioned above and equal to or greater than any of the lower limits mentioned above. The EIS conductivity may be measured by the method described in "4. EIS (Electrochemical Impedance Spectroscopy) Conductivity (ohms) Evaluation Method" in the Examples section of this specification.

[0029] Since the polymer layer, current collector, or electrode exhibits the DC resistance, AC impedance resistance, and / or EIS conductivity, a secondary battery or electrode assembly to which the polymer layer, etc. is applied can be stably operated or stored under normal and storage conditions.

[0030] The current collector and electrode to which the polymer layer is applied can ensure stability through an increase in resistance under abnormal conditions.

[0031] For example, the polymer layer, current collector, or electrode may exhibit properties such that R in the following formula A falls within a predetermined range.

[0032] [Formula A] R=R MAX / R MIN

[0033] R in formula A MAX is the maximum EIS resistance of the polymer layer or current collector observed in the temperature range of 25°C to 135°C, and R MINis the minimum EIS resistance of the polymer layer or current collector observed in the temperature range of 25°C to 135°C.

[0034] R in Formula A MAX and R MIN can be evaluated using a coin cell using the polymer layer or current collector, and a specific method is summarized in "5. Measurement of Maximum Resistance Change Rate (EIS Resistance)" in the Examples section (Maximum Resistance Change Rate Measurement Using Coin Cell 1 in the previous section). In the method for determining R, the initial temperature is 25°C and the final temperature is 135°C. Starting from the initial temperature of 25°C, the temperature is increased by 5°C at each temperature, and the EIS resistance is measured at each temperature to determine the maximum and minimum values ​​of the EIS resistance. A larger R value indicates that the PTC effect of the polymer is being properly exerted.

[0035] The lower limit of R may be about 100, 150, 200, 250, 300, 350, 400, 450, or 500, and the upper limit may be about 1500, 1400, 1300, 1200, 1100, 1000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, or 450. R may be within a range that is equal to or greater than any of the aforementioned lower limits; or it may be within a range that is equal to or less than any of the aforementioned upper limits, but is equal to or greater than any of the aforementioned lower limits.

[0036] R of Formula A MAXThe lower limit may be about 7,000 ohms, 8,000 ohms, 9,000 ohms, 10,000 ohms, 11,000 ohms, 15,000 ohms, 16,000 ohms, 17,000 ohms or 18,000 ohms, and the upper limit may be about 100,000 ohms, 95,000 ohms, 90,000 ohms, 85,000 ohms, 80,000 ohms or 95,000 ohms. The resistance may be about 0,000 ohms, 75,000 ohms, 70,000 ohms, 65,000 ohms, 60,000 ohms, 55,000 ohms, 50,000 ohms, 45,000 ohms, 40,000 ohms, 35,000 ohms, 30,000 ohms, 25,000 ohms, 20,000 ohms or 15,000 ohms. MAX may have a range that is greater than or equal to any of the aforementioned lower limits; or a range that is less than or equal to any of the aforementioned upper limits, but greater than or equal to any of the aforementioned lower limits.

[0037] R MAX The lower limit of the temperature at which R is confirmed may be about 70°C, 75°C, 80°C, 85°C, or 90°C, and the upper limit may be about 135°C, 130°C, 120°C, 110°C, 100°C, 95°C, or 90°C. The temperature may be in a range that is less than or equal to any of the upper limits mentioned above; or in a range that is greater than or equal to any of the lower limits mentioned above; or in a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above. MAX The temperature above means that the resistance of the conductive polymer increases at or near the temperature above. Therefore, controlling the temperature is important in terms of ensuring stable performance under normal conditions and stability under abnormal conditions.

[0038] R MINThe lower limit of the temperature at which this is confirmed may be on the order of 25° C., 26° C., 27° C., 28° C., 29° C., 30° C., 35° C., 40° C., 45° C., 50° C., 55° C., or 60° C., and the upper limit may be on the order of 80° C., 75° C., 70° C., 65° C., 60° C., 55° C., 50° C., 45° C., 40° C., 39° C., 38° C., 37° C., 36° C., 35° C., 34° C., 33° C., 32° C., 31° C., 30° C., 29° C., 28° C., 27° C., 26° C., or 25° C. The temperature may be in a range less than or equal to any of the upper limits mentioned above; or may be in a range less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above.

[0039] R in Formula A MIN The lower limit of R may be about 0 ohms, 5 ohms, 10 ohms, 15 ohms, 20 ohms, 25 ohms, 30 ohms, 35 ohms, or 40 ohms, and the upper limit may be about 100 ohms, 95 ohms, 90 ohms, 85 ohms, 80 ohms, 75 ohms, 70 ohms, 65 ohms, 60 ohms, 55 ohms, 50 ohms, 45 ohms, 40 ohms, 35 ohms, or 30 ohms. MIN may range up to or below any of the aforementioned upper limits; or may range up to or below any of the aforementioned upper limits, but up to or above any of the aforementioned lower limits.

[0040] The polymer layer, current collector, or electrode may exhibit a property such that ΔR1 in the following formula 1 falls within a predetermined range.

[0041] [Formula 1] △R1=Max{(R n+5 / R n ) / 5}

[0042] In Equation 1, R n is the DC resistance at any temperature n°C between 25°C and 135°C, and R n+5 is the DC resistance at a temperature 5°C higher than the temperature n°C ((n+5)°C), and Max{(Rn+5 / R n ) / 5} was confirmed within the temperature range of 25℃ to 135℃ (R n+5 / R n ) / 5 is the maximum value.

[0043] ΔR1 in Equation 1 can be measured in the above temperature range according to the method for measuring DC resistance. In the method for determining ΔR1, the initial temperature is 25°C and the final temperature is 135°C. The temperature is increased by 5°C from the initial temperature of 25°C, and the DC resistance is measured at each temperature to determine the R n+5 and R n For example, if n is 90, then R 95 / R 90 is the ratio of the DC resistance at 95°C to the DC resistance at 90°C. For example, if ΔR1 is 100 / °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, current collector, or electrode increases relatively rapidly at any temperature within the temperature range.

[0044] The lower limit of ΔR1 may be about 80°C, 90°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, or 400°C, and the upper limit may be about 1,000°C, 950°C, 900°C, 850°C, 800°C, 750°C, 700°C, 650°C, 600°C, 550°C, 500°C, 450°C, 400°C, 350°C, 300°C, 250°C, 200°C, or 150°C. ΔR1 may be within a range that is equal to or exceeds any of the lower limits mentioned above; or it may be within a range that is equal to or exceeds any of the upper limits mentioned above while being equal to or less than any of the upper limits mentioned above.

[0045] By ensuring the above-mentioned characteristics, the current collector or the electrode to which it is applied increases in resistance under abnormally high temperature conditions caused by overcharging, exposure to high temperatures, or external impact, thereby cutting off the current flow to the electrode assembly and ensuring stability.

[0046] The temperature at which ΔR1 is confirmed, i.e., R n The lower temperature limit may be on the order of 70° C., 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 on the order of 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 in a range that is less than or equal to any of the upper limits mentioned above; or in a range that is greater than or equal to any of the lower limits mentioned above; or in a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above. By designing the polymer layer, current collector, or electrode as described above, it is possible to maintain the performance of the electrode, electrode assembly, or secondary battery even when the electrode, electrode assembly, or secondary battery is maintained at a relatively high temperature under normal conditions, while ensuring stability under abnormal conditions.

[0047] The polymer layer, current collector, or electrode may exhibit a characteristic in which ΔR2 in the following formula 2 is within a predetermined range.

[0048] [Formula 2] △R2=Max{(R z+5 / R z ) / 5}

[0049] R in Equation 2 z is the AC impedance resistance at any temperature n°C within the range of 25°C to 135°C, and R z+5 is the AC impedance resistance at a temperature 5°C higher than the temperature n°C ((n+5)°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.

[0050] ΔR2 in Equation 2 can be measured in the temperature range according to the method for measuring the AC impedance resistance. In the method for determining ΔR2, the initial temperature is 25°C and the final temperature is 135°C. The temperature is increased by 5°C from the initial temperature of 25°C, and the AC impedance resistance is measured at each temperature. z+5 and R z For example, if n is 90, then R 95 / R 90 is the ratio of the AC impedance resistance at 95°C to the AC impedance resistance at 90°C. For example, if ΔR2 is 10 / °C or greater at any temperature within the temperature range of 25°C to 135°C, this means that the resistance of the polymer layer, current collector, or electrode increases relatively rapidly at any temperature within the temperature range.

[0051] The lower limit of ΔR2 may be about 8 / °C, 10 / °C, 12 / °C, 14 / °C, 16 / °C, 18 / °C, 20 / °C, 22 / °C, 24 / °C, 26 / °C, 28 / °C, 30 / °C, 33 / °C, 34 / °C, 36 / °C, 38 / °C, 40 / °C, 42 / °C, or 44 / °C, and the upper limit may be about 100 / °C, 95 / °C, 90 / °C, 85 / °C, 80 / °C, 75 / °C, 70 / °C, 65 / °C, 60 / °C, 55 / °C, 50 / °C, 45 / °C, 40 / °C, 35 / °C, 30 / °C, 25 / °C, 20 / °C, 18 / °C, or 16 / °C. The ΔR2 may be in a range that is less than or equal to any of the upper limits mentioned above; or in a range that is greater than or equal to any of the lower limits mentioned above; or in a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above.

[0052] By ensuring the above characteristics, the resistance of the current collector or electrode increases in an abnormal state, thereby ensuring stability.

[0053] The temperature at which ΔR2 in the above range is confirmed, i.e., R zThe lower temperature limit may be about 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 temperature limit may be about 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 in a range that is less than or equal to any of the upper limits mentioned above; or in a range that is greater than or equal to any of the lower limits mentioned above; or in a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above. By designing the electrode so that the above temperature is exhibited, it is possible to maintain the performance of the electrode, electrode assembly, or secondary battery even when the current collector, electrode, electrode assembly, or secondary battery is maintained at a relatively high temperature under normal conditions, while ensuring stability under abnormal conditions.

[0054] The polymer layer, current collector, or electrode may exhibit a characteristic in which the absolute value of ΔR3 in the following formula 3 is within a predetermined range.

[0055] [Formula 3] △R3=100×(C1-C2) / C1

[0056] In Equation 3, C1 is the discharge capacity at room temperature (about 25°C), and C2 is the discharge capacity after 60 hours of storage at 70°C. C1 and C2 in Equation 3 are the discharge capacities measured for the coin cell to which the electrode was applied.

[0057] The upper limit of the absolute value of ΔR3 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%, 1%, or 0.5%, and the lower limit may be approximately 0%, 0.5%, or 1.5%. The absolute value may be within a range equal to or less than any of the upper limits; or within a range equal to or greater than any of the lower limits; or within a range equal to or less than any of the upper limits but equal to or greater than any of the lower limits. By designing to ensure these characteristics, the performance of the electrode, electrode assembly, or secondary battery can be maintained even when the electrode, electrode assembly, or secondary battery is maintained at a relatively high temperature under normal conditions, while ensuring stability under abnormal conditions.

[0058] The polymer layer, current collector, or electrode may exhibit a characteristic in which the absolute value of ΔR4 in the following formula 4 is within a predetermined range.

[0059] [Formula 4] △R4=100×(C1-C3) / C1

[0060] In Equation 4, C1 is the discharge capacity at room temperature (about 25°C), and C3 is the discharge capacity after 10 minutes of storage at 130°C. C1 and C3 in Equation 4 are the discharge capacities measured for the coin cell to which the electrode was applied.

[0061] The lower limit of the absolute value of ΔR4 in Equation 4 may be approximately 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, or 76%, and the upper limit may be approximately 200%, 180%, 160%, 140%, 120%, 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, or 60%. The range of the absolute value may be within a range that is less than or equal to any of the above upper limits, or within a range that is greater than or equal to any of the above lower limits, or within a range that is less than or equal to any of the above upper limits and greater than or equal to any of the above lower limits. By designing the electrode so that the above characteristics are ensured, stability can be ensured under abnormal conditions.

[0062] Said properties can be achieved through the introduction of polymer layers as described below.

[0063] The current collector body is not particularly limited, and may be any current collector body that is commonly used for positive or negative electrodes.

[0064] The current collector body may be any material that does not undergo chemical changes in an application device such as a secondary battery and has conductivity, without particular limitations on its type, size, or shape. Examples of materials that can be used for the current collector body include copper, aluminum, stainless steel, nickel, titanium, and calcined carbon. Examples include copper, aluminum, or stainless steel surfaces that have been surface-treated with carbon, nickel, titanium, or silver. The current collector body may be in the form of a film, sheet, foil, net, porous material, foam, or nonwoven fabric containing the above material. In some cases, the surface of the current collector body may be subjected to a known surface treatment to improve adhesion to other layers, such as a polymer layer or an active material layer.

[0065] Such a current collector body can usually have a thickness in the range of 3 μm to 500 μm, but is not limited to this.

[0066] The active material layer used to form an electrode may be a commonly used layer. Typically, the active material layer includes an electrode active material. The specific type of the electrode active material is not particularly limited, and materials commonly used to form a positive electrode or a negative electrode may be used.

[0067] For example, when 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; a lithium iron oxide such as LiFe3O4; 1+c1 Mn 2-c1 O4 (0≦c1≦0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, or Cu2V2O7; chemical formula LiNi 1-c2 M c2 Ni-site type lithium nickel oxide represented by the formula LiMnO2 (wherein M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01≦c2≦0.3); 2-c3 M c3 The lithium manganese composite oxide may be, but is not limited to, a lithium manganese composite oxide expressed as Li2Mn3MO8 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfies 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); a lithium nickel cobalt manganese (NCM) composite oxide, a lithium nickel cobalt manganese aluminum (NCMA) composite oxide, and LiMn2O4 in which part of the Li in the chemical formula is substituted with an alkaline earth metal ion.

[0068] 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 oxides, and lithium vanadium oxides that can be doped and undoped with lithium; or composites containing the metallic compound and the carbonaceous material such as Si-C composites or Sn-C composites, etc. can be mentioned, and any one or a mixture of two or more of these can be used.

[0069] 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. can also 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.

[0070] The electrode active material may be contained within the active material layer in the range of about 80% to 99.5% by weight or 88% to 99% by weight 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.

[0071] The active material layer may further include a binder. The binder serves to improve adhesion between 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. At least one selected from the group consisting of sucrose, pullulan, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyarylate, etc. may be used.

[0072] The binder may be included in the active material layer in an amount of, for example, 0.1 to 10 parts by weight or 0.5 to 5 parts by weight relative to 100 parts by weight of the electrode active material, but is not limited thereto.

[0073] The active material layer may further include a conductive material, if necessary. Any known conductive material may be used as long as it does not induce chemical changes in the secondary battery and is conductive. Examples of such conductive materials include graphite, such as natural graphite or artificial graphite; carbon black, such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers, such as carbon fiber and metal fiber; 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.

[0074] The conductive material may be contained in the active material layer in an amount of 0.1 to 20 parts by weight or 0.3 to 10 parts by weight relative to 100 parts by weight of the electrode active material, but is not limited thereto.

[0075] The active material layer may optionally contain necessary known components in addition to the components described above.

[0076] The polymer layer on the current collector body may include a conductive polymer, which is a polymer that exhibits conductivity due to a conjugated polymer chain and / or doping, as is well known.

[0077] The conductive polymer may be a polymer having a so-called PTC (Positive Temperature Coefficient) characteristic, and an electrode exhibiting the above-mentioned characteristics can be effectively formed by controlling the PTC characteristic of the polymer.

[0078] The polymer layer may contain only the conductive polymer, or may further contain the conductive polymer and other necessary additives. For example, the lower limit of the conductive polymer content in the polymer layer may be about 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, based on the total weight of the polymer layer, and the upper limit may be about 100 wt%, 95 wt%, 90 wt%, or 85 wt%, based on the total weight of the polymer layer. The content may range within a range that is less than or equal to any of the aforementioned upper limits; or greater than or equal to any of the aforementioned lower limits; or between a range that is less than or equal to any of the aforementioned upper limits and greater than or equal to any of the aforementioned lower limits.

[0079] The polymer layer is a layer distinct from the active material layer described above. Specifically, the polymer layer is distinct from the active material layer in that the content of the electrode active material contained therein is limited or the polymer layer does not contain the electrode active material. For example, the upper limit of the electrode active material content in the polymer layer may be about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, or 0.1 wt%, based on the total weight of the polymer layer, and the lower limit may be about 0 wt%, 0.1 wt%, 0.5 wt%, or 1 wt%, based on the total weight of the polymer layer. The content may range within a range equal to or less than any of the above upper limits; or within a range equal to or less than any of the above upper limits and equal to or greater than any of the above lower limits.

[0080] The conductive polymer may have a weight-average molecular weight within a predetermined range, and the lower limit of the weight-average molecular weight of the conductive polymer may be 10,000 g / mol, 15,000 g / mol, 20,000 g / mol, 25,000 g / mol, 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, or 65,000 g / mol. l, 70,000g / mol, 75,000g / mol, 80,000g / mol, 85,000g / mol, 90,000g / mol, 95,000g / mol, 100,000g / mol, 105,000g / mol, 110,000g / mol, 115,000g / mol, 120,000g / mol, 125,000g / mol, 130,000g / mol , 135,000 g / mol, 140,000 g / mol, 145,000 g / mol, or 150,000 g / mol, with upper limits of 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 The weight-average molecular weight may be about 1,000 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 that is less than or equal to any of the upper limits recited above; or a range that is greater than or equal to any of the lower limits recited above; or a range that is less than or equal to any of the upper limits recited above and greater than or equal to any of the lower limits recited above. By using a conductive polymer having such a weight-average molecular weight, polymer layers and electrodes with desired properties can be effectively formed.

[0081] The molecular weight distribution of the conductive polymer, i.e., the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), may be within a predetermined range. The lower limit of the molecular weight distribution may be about 2, 2.5, 3, 3.5, or 4, and the upper limit may be about 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, or 3.5. The molecular weight distribution may be within a range that is less than or equal to any of the above upper limits; or a range that is greater than or equal to any of the above lower limits; or a range that is less than or equal to any of the above upper limits but greater than or equal to any of the above lower limits. By using a conductive polymer having such a molecular weight distribution, polymer layers, current collectors, and electrodes with desired properties can be effectively formed.

[0082] The weight average molecular weight and molecular weight distribution can be measured by the method described in "2. GPC (Gel Permeation Chromatograph)" in the Examples section of this specification.

[0083] The conductive polymer may be polythiophene or a thiophene polymer. By using polythiophene or a thiophene polymer as the conductive polymer, a desired polymer layer can be efficiently formed. As used herein, the term "polythiophene" or "thiophene polymer" refers to a polymer containing a certain level of thiophene units. The thiophene unit refers to a monomer unit formed by polymerizing a thiophene-based monomer, and the thiophene-based monomer refers to a monomer containing a thiophene skeleton.

[0084] The term "monomer unit" refers to a structure in which a monomer is polymerized and contained within a polymer.

[0085] The lower limit of the ratio of thiophene units in the thiophene polymer may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, or 90 mol%, and the upper limit may be about 100 mol%, 95 mol%, 90 mol%, 85 mol%, 80 mol%, 75 mol%, 70 mol%, 65 mol%, 60 mol%, or 55 mol%. The ratio of thiophene units may be within a range equal to or greater than any of the above-mentioned lower limits; or within a range equal to or less than any of the above-mentioned upper limits, but equal to or greater than any of the above-mentioned lower limits.

[0086] The conductive polymer may include a unit of the following chemical formula A as the thiophene unit.

[0087] [ka]

[0088] In Formula A, R1 and R2 can each independently be hydrogen, a polar functional group, or a hydrocarbon functional group.

[0089] In another example, R1 and R2 of formula A may be linked together to form a divalent functional group of formula B below.

[0090] [ka]

[0091] In Formula B, L1 and L2 can each independently be a single bond, an alkylene group, or an alkylidene group, and R3 and R4 can each independently be hydrogen, the polar functional group, or the hydrocarbon functional group.

[0092] In Formula A, when R1 and R2 are each independently hydrogen, the polar functional group, or the hydrocarbon functional group, at least one of R1 and R2 may be the polar functional group or the hydrocarbon functional group.

[0093] In the case where R1 and R2 in the formula A form a divalent functional group of the formula B, at least one of R3 and R4 can be the polar functional group or the hydrocarbon functional group.

[0094] As used herein, the term "alkylene group" refers to a divalent functional group formed by removing hydrogen atoms from two different carbon atoms of an alkane, and the term "alkylidene group" refers to a divalent functional group formed by removing two hydrogen atoms from one carbon atom of an alkane.

[0095] As used herein, the term "alkylene group" refers 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.

[0096] As used herein, unless otherwise specified, the term "alkylidene group" may refer to an alkylidene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkylidene group may be linear, branched, or cyclic, and may be optionally substituted with one or more substituents.

[0097] As used herein, the term "hydrocarbon functional group" refers to a monovalent hydrocarbon group (i.e., a monovalent functional group consisting of carbon and hydrogen) or a monovalent functional group containing the monovalent hydrocarbon group. Therefore, the hydrocarbon functional group may contain atoms other than carbon and hydrogen. Examples of the monovalent hydrocarbon group include an alkyl group, an alkynyl group, or an alkenyl group, and examples of the monovalent functional group containing the monovalent hydrocarbon group include an alkoxy group, an alkylcarbonyl group, or an alkylcarbonyloxy group, but the types of hydrocarbon functional groups are not limited to these.

[0098] The hydrocarbon functional group is a functional group that can impart appropriate mobility to the conductive polymer itself or to the polymerization process of the conductive polymer. Monomers containing such hydrocarbon functional groups impart appropriate mobility to the monomer mixture and diffuse within the monomer mixture, enabling efficient polymerization. Furthermore, conductive polymers having hydrocarbon functional groups can ensure stable and uniform formation of a polymer layer between the current collector body and the active material layer through their appropriate fluidity, and can more effectively form the polymer layer through their interaction with additives, which will be described later.

[0099] When a certain amount of thermal energy is applied, the hydrocarbon functional group vibrates due to the heat. This vibration (thermal vibration) promotes the dedoping of anions bound to the polymer, 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 functional 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 therefore, the long chain can induce a resistance increase effect at a relatively low temperature. Therefore, the desired PTC effect can be achieved by controlling the length and / or ratio of the hydrocarbon functional group.

[0100] The type of hydrocarbon functional group is not particularly limited as long as it performs the above-mentioned function, but hydrocarbon functional groups having a chain structure with a certain level of length or more can be suitably applied in the present invention.

[0101] For example, the lower limit of the number of carbon atoms in the hydrocarbon functional group may be about 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, and the upper limit may be about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, or 6. The number of carbon atoms in the hydrocarbon functional group may be within a range that is less than or equal to any of the above upper limits; or within a range that is greater than or equal to any of the above lower limits; or within a range that is less than or equal to any of the above upper limits but greater than or equal to any of the above lower limits.

[0102] The carbon number may be the total number of carbon atoms in the hydrocarbon functional group or the monovalent hydrocarbon group contained therein, or the carbon number of the longest linear hydrocarbon chain contained in the hydrocarbon functional group or the monovalent hydrocarbon group contained therein. That is, the hydrocarbon functional group or monovalent hydrocarbon group may have a linear or branched chain structure, and even if it has a branched chain structure, the number of carbon atoms constituting the longest linear chain in the branched chain structure may be within the above range. For example, if the branched chain structure is a 2-ethylhexyl group structure, the number of carbon atoms constituting the longest chain may be 6.

[0103] The hydrocarbon functional group may have, for example, a straight-chain or branched-chain structure. Specifically, the hydrocarbon functional group may be a straight-chain or branched-chain alkyl group, alkenyl group, or alkynyl group, or an alkoxy group, alkylcarbonyl group, or alkylcarbonyloxy group containing a straight-chain or branched-chain alkyl group. In such cases, the carbon number of the alkyl group of the alkyl group, alkenyl group, alkynyl group, or alkoxy group, alkylcarbonyl group, or alkylcarbonyloxy group may be within the carbon number of the hydrocarbon functional group. The hydrocarbon functional group may be optionally substituted with one or more substituents, and in such cases, the carbon number may be within the aforementioned range.

[0104] A polar functional group is a functional group containing one or more polar atoms, such as oxygen and / or nitrogen. Examples of such polar functional groups include 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 formula 5:

[0105] [ka]

[0106] In Chemical Formula 5, L5 is a single bond, an alkylene group, or an alkylidene group; L6 is an alkylene group or an alkylidene group; R5 is hydrogen or an alkyl group; and n is a number within the range of 1-10.

[0107] In Chemical Formula 5, L5 being a single bond means that L5 is absent and the oxygen atom between L5 and L6 is linked to the backbone of a monomer or polymer.

[0108] The alkyl group of R9 in Chemical Formula 5 may be, for example, 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 may be a methyl group or an ethyl group. The alkyl group may be linear, branched, or cyclic, and may be suitably linear or branched.

[0109] The alkylene groups of L5 and L6 in Chemical Formula 5 may be, for example, alkylene groups having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, or may be ethylene or propylene groups. The alkylene groups may be linear, branched, or cyclic, and may be appropriately linear or branched.

[0110] The alkylidene groups of L5 and L6 in Chemical Formula 5 may be, for example, 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, or may be methylidene, ethylidene, or propylidene groups. The alkylidene groups may be linear, branched, or cyclic, and may be appropriately linear or branched.

[0111] In Chemical Formula 5, the lower limit of n may be about 1, 2, 3, or 4, and the upper limit may be about 10, 9, 8, 7, 6, 5, 4, or 3. The n may be in a range that is less than or equal to any of the upper limits mentioned above; or in a range that is greater than or equal to any of the lower limits mentioned above; or in a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above.

[0112] By applying the polar functional group, a polymer layer including a conductive polymer can be bonded to other layers with appropriate bonding strength, and such a conductive polymer layer can be uniformly formed to efficiently achieve the intended protective function.

[0113] In the conductive polymer, the lower limit of the number of moles of units of Formula A relative to the total polymerized units may be about 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 about 100 mol%, 95 mol%, 90 mol%, 85 mol%, 80 mol%, 75 mol%, 70 mol%, 65 mol%, 60 mol%, or 55 mol%. The ratio may be within a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits.

[0114] To achieve appropriate properties, the conductive polymer may include a thiophene unit having a relatively long chain hydrocarbon functional group (hereinafter referred to as a first thiophene unit) and a thiophene unit having a relatively short chain hydrocarbon functional group (hereinafter referred to as a second thiophene unit). Such a conductive polymer is a conductive copolymer.

[0115] The lower limit of the number of carbon atoms in the long chain hydrocarbon functional group may be about 10, 11, or 12, and the upper limit may be about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10. The number of carbon atoms in the long chain hydrocarbon functional group may be within a range that is equal to or greater than any of the aforementioned lower limits; or within a range that is equal to or less than any of the aforementioned upper limits, but is equal to or greater than any of the aforementioned lower limits.

[0116] The lower limit of the number of carbon atoms in the short-chain hydrocarbon functional group may be about 3, 4, 5, 6, 7, or 8, and the upper limit may be about 9, 8, 7, or 6. The number of carbon atoms in the short-chain hydrocarbon functional group may be within a range equal to or less than any of the above upper limits; or may be within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits.

[0117] With respect to the long-chain and short-chain hydrocarbon functional groups, except for the aforementioned number of carbon atoms, other matters, such as the meaning of the carbon number and the specific type of functional group, follow the description of the hydrocarbon functional group.

[0118] Therefore, specific types of the long-chain and short-chain hydrocarbon functional groups may include straight-chain or branched-chain alkyl groups, alkenyl or alkynyl groups, straight-chain or branched-chain alkoxy groups, alkylcarbonyl groups, or alkylcarbonyloxy groups, and the carbon number of the alkyl group of the alkyl group, alkenyl or alkynyl group, alkoxy group, alkylcarbonyl group, or alkylcarbonyloxy group may be within the above-mentioned range.

[0119] The conductive copolymer may have a lower limit of the ratio of the total mole number of the first and second thiophene units based on the mole number of all monomer units of the conductive copolymer, which may be about 80 mol%, 82 mol%, 84 mol%, 86 mol%, or 86 mol%, and an upper limit of about 99 mol%, 97 mol%, 95 mol%, 93 mol%, 91 mol%, or 90 mol%. The ratio may be within a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits.

[0120] The ratio (M2 / M1) of the moles of the second thiophene units (M2) to the moles of the first thiophene units (M1) in the conductive copolymer may have a lower limit of about 0.01, 0.05, 0.1, 0.5, 1, 1.5, or 2, and an upper limit of about 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, or 0.7. The ratio may be in a range that is less than or equal to any of the aforementioned upper limits; or in a range that is greater than or equal to any of the aforementioned lower limits; or in a range that is less than or equal to any of the aforementioned upper limits but greater than or equal to any of the aforementioned lower limits.

[0121] Under such a ratio, the conductive copolymer or the polymer layer exhibits an appropriate PTC (Positive Temperature Coefficient) effect, and its surface properties are controlled to ensure excellent adhesion to the electrode or current collector.

[0122] In one example, the first thiophene unit may be represented by the following Formula 1:

[0123] [ka]

[0124] In Formula 1, R1 and R2 may each independently be hydrogen or the long chain hydrocarbon functional group. In this case, at least one of R1 and R2 may be the long chain hydrocarbon functional group.

[0125] In another example, R1 and R2 may be linked to each other to form a divalent functional group of the following formula 2:

[0126] [ka]

[0127] In Chemical Formula 2, L1 and L2 are each independently a single bond, an alkylene group, or an alkylidene group, and R3 and R4 are each independently hydrogen or the long chain hydrocarbon functional group, but at least one of R3 and R4 may be the long chain hydrocarbon functional group.

[0128] Specific details regarding the long chain hydrocarbon functional group are as described above, and specific details regarding the alkylene or alkylidene group are as described in Formulas A, B, and 5 above.

[0129] The second thiophene unit may be represented by the following Chemical Formula 3:

[0130] [ka]

[0131] In Formula 3, R5 and R6 may each independently be hydrogen or the short chain hydrocarbon functional group, and in this case, at least one of R5 and R6 may be the short chain hydrocarbon functional group.

[0132] In another example, R5 and R6 may be linked to each other to form a divalent functional group of Formula 4 below.

[0133] [ka]

[0134] In Chemical Formula 4, L3 and L4 are each independently a single bond, an alkylene group, or an alkylidene group, and R7 and R8 are each independently hydrogen or the short chain hydrocarbon functional group, provided that at least one of R7 and R8 is the short chain hydrocarbon functional group.

[0135] The specific details of the short chain hydrocarbon functional group are as described above, and the specific details of the alkylene group and alkylidene group are as described in Formulas A, B, and 5 above.

[0136] The conductive polymer may further include necessary units in addition to the above units.

[0137] For example, the conductive polymer may further include a thiophene unit having the polar functional group (hereinafter, may be referred to as a third thiophene unit).

[0138] Examples of the polar functional group are as described above.

[0139] By applying the polar functional group, a polymer layer including a conductive polymer can be bonded to other layers with appropriate bonding strength, and such a conductive polymer layer can be uniformly formed to efficiently achieve the intended protective function.

[0140] The third thiophene unit may be represented, for example, by the following Chemical Formula 6:

[0141] [ka]

[0142] R in Chemical Formula 6 10 and R 11may each independently be hydrogen or the polar functional group, in which case the R 10 and R 11 At least one of the groups is the polar functional group.

[0143] In another example, R 10 and R 11 can be linked together to form a divalent functional group of the following formula 7:

[0144] [ka]

[0145] In Chemical Formula 7, L7 and L8 are each independently a single bond, an alkylene group, or an alkylidene group; R 12 and R 13 are each independently hydrogen or a polar functional group, but R 12 and R 13 At least one of the groups is the polar functional group.

[0146] Specific details regarding the polar functional group are as described above, and specific details regarding the alkylene group or alkylidene group are as described in Formulas A, B, and 5 above.

[0147] When the third thiophene unit is present in the conductive copolymer, the third thiophene unit may 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.

[0148] For example, the lower limit of the ratio of the total number of moles of the first and second thiophene units (M) per mole of the third thiophene unit (M3) (i.e., M / M3) may be about 1 mole, 2 moles, 3 moles, 4 moles, 5 moles, 6 moles, 8 moles, 8.5 moles, 9 moles, 10 moles, 11 moles, 12 moles, 13 moles, 14 moles, 15 moles, 16 moles, 17 moles, or 19 moles, and the upper limit thereof may be about 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, or 10 moles. The ratio may be in a range that is less than or equal to any of the aforementioned upper limits; or greater than or equal to any of the aforementioned lower limits; or less than or equal to any of the aforementioned upper limits but greater than or equal to any of the aforementioned lower limits.

[0149] When the first to third thiophene units are present in the conductive polymer, the lower limit of the ratio of the total number of moles of the first to third thiophene units in the conductive polymer relative to the total polymer units may be about 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 about 100 mol%, 95 mol%, 90 mol%, 85 mol%, 80 mol%, 75 mol%, 70 mol%, 65 mol%, 60 mol%, or 55 mol%. The ratio may be within a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits.

[0150] The conductive polymer may further contain other polymer units as long as it contains the above-mentioned units in the above-mentioned proportions.

[0151] The polymer layer includes the conductive polymer and can therefore exhibit the above-described properties.

[0152] The polymer layer may also contain any additional components as long as it contains the conductive polymer.

[0153] For example, the polymer layer may further include a conductive material in addition to the conductive polymer. The conductive material may be a material having appropriate conductivity, such as one or more materials selected from the group consisting of carbon particles, carbon fiber, graphene, graphite, carbon black, and carbon nanotubes.

[0154] The conductive material may be selected from the above-described types appropriately, and the shape of the material may be, but is not limited to, particulate (spherical, irregular, or other shapes), plate-like, or fibrous.

[0155] The size of the conductive material may also be appropriately adjusted as needed. For example, the lower limit of the size of the conductive material may be about 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 5000 nm, or 10000 nm, and the upper limit may be about 100,000 nm, 90,000 nm, 800 nm, or 10000 nm. The magnitude may be on the order of 00 nm, 70,000 nm, 60,000 nm, 50,000 nm, 40,000 nm, 30,000 nm, 20,000 nm, 10,000 nm, 5,000 nm, 1,000 nm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, 600 nm, 550 nm, 500 nm, 450 nm, 400 nm, 350 nm, 300 nm, 250 nm, 200 nm, 200 nm, or 150 nm. The magnitude may be within a range that is less than or equal to any of the upper limits recited above; or within a range that is greater than or equal to any of the lower limits recited above; or within a range that is less than or equal to any of the upper limits recited above, but greater than or equal to any of the lower limits recited above. The size may be the average diameter (so-called D50 particle size) if the conductive material is particulate, the thickness, long side or cross section if the conductive material is plate-shaped, or the diameter or length of the cross section if the conductive material is fibrous.

[0156] When the conductive material is fibrous, the lower limit of its aspect ratio (length / cross-sectional diameter) may be about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65, and the upper limit may be about 200, 195, 190, 185, 180, 175, 170, 165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, or 70. The aspect ratio may be within a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits.

[0157] If necessary, the conductive material may be surface-treated in consideration of dispersibility.

[0158] In this case, a surface treatment agent having suitable compatibility with the conductive polymer can be used. For example, the conductive material may be surface-treated with a polyphenol-based compound. A polyphenol-based compound refers to a compound having a structure containing two or more linked hydroxyl groups substituted on a benzene ring. Examples of such compounds include so-called catechol-based compounds (i.e., catechol or compounds containing a corresponding structure), including, but not limited to, dopamine, polydopamine, 3,4-dihydroxyphenylalanine, norepinephrine, tannic acid, humic acid, and / or lignin.

[0159] There is no limitation on the method for surface-treating the conductive material with the surface treatment agent. For example, a method of mixing the conductive material and the surface treatment agent in an appropriate solvent or a method of synthesizing or polymerizing the surface treatment agent on the surface of the conductive material may be applied.

[0160] When the conductive material is used, the content of the conductive material in the polymer layer relative to 100 parts by weight of the conductive polymer may be about 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight, and the content of the conductive material in the polymer layer may be about 50 parts by weight, 48 parts by weight, 46 parts by weight, 44 parts by weight, 42 parts by weight, 40 parts by weight, 38 parts by weight, 36 parts by weight, 34 parts by weight, 32 parts by weight, 30 parts by weight, 28 parts by weight, 26 parts by weight, 24 parts by weight, 22 parts by weight, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, or 10 parts by weight. The content may be in a range that is less than or equal to any of the upper limits recited above; or in a range that is greater than or equal to any of the lower limits recited above; or in a range that is less than or equal to any of the upper limits recited above, but greater than or equal to any of the lower limits recited above.

[0161] At this ratio, the conductive material can appropriately interact with the conductive polymer, allowing a polymer layer of a desired shape to be effectively formed.

[0162] The polymer layer may further include an aralkyl-modified silicone compound as an additive component. This compound, when mixed with the conductive polymer, may enable the polymer layer to be stably formed on the current collector body and between the current collector body and the active material layer. It is believed that the aralkyl group contained in the silicone compound interacts with the flowable functional groups present in the conductive polymer to exhibit the above-described effect.

[0163] The aryl group in the aralkyl group may be a monovalent functional group formed by removing one hydrogen atom from benzene, a benzene derivative, a compound in which two or more benzenes are linked by one or more carbon atoms shared by the aryl group or by a linker, or a derivative thereof. The lower limit of the number of carbon atoms in the aryl group may be about 6, 7, 8, 9, 10, 11, or 12, and the upper limit may be about 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, or 6. The number of carbon atoms may be less than or equal to any of the upper limits; or may be greater than or equal to any of the lower limits; or may be less than or equal to any of the upper limits but greater than or equal to any of the lower limits. Examples of aryl groups include, but are not limited to, phenyl and naphthyl groups.

[0164] The lower limit of the number of carbon atoms in the alkyl group present in the aralkyl group may be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19, and the upper limit may be about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2. The number of carbon atoms may be within a range that is less than or equal to any of the above upper limits; or greater than or equal to any of the above lower limits; or within a range that is less than or equal to any of the above upper limits but greater than or equal to any of the above lower limits. The alkyl group may be straight-chain, branched-chain or cyclic, and may be optionally substituted with one or more non-aryl substituents.

[0165] The silicone compound is not particularly limited in its specific type as long as it is modified with the aralkyl group. For example, the silicone compound may be an aralkyl-modified polymethylalkylsiloxane. The lower limit of the number of carbon atoms in the alkyl group present in the polymethylalkylsiloxane may be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19, and the upper limit may be about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2. The number of carbon atoms may be in a range of less than or equal to any of the upper limits set forth above; or in a range of more than or equal to any of the lower limits set forth above; or in a range of less than or equal to any of the upper limits set forth above but more than or equal to any of the lower limits set forth above. The alkyl group may be straight-chain, branched-chain, or cyclic, and may be substituted with one or more substituents, if necessary.

[0166] Various additives such as these are known in the art, and for example, BYK-323 from BYK-Chemie may be used as the additive.

[0167] When the silicone compound is used, the content of the silicone compound in the polymer layer relative to 100 parts by weight of the conductive polymer may be about 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight, and the content of the silicone compound in the polymer layer may be about 50 parts by weight, 48 parts by weight, 46 parts by weight, 44 parts by weight, 42 parts by weight, 40 parts by weight, 38 parts by weight, 36 parts by weight, 34 parts by weight, 32 parts by weight, 30 parts by weight, 28 parts by weight, 26 parts by weight, 24 parts by weight, 22 parts by weight, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, or 10 parts by weight. The content may be in a range that is less than or equal to any of the upper limits recited above; or in a range that is greater than or equal to any of the lower limits recited above; or in a range that is less than or equal to any of the upper limits recited above, but greater than or equal to any of the lower limits recited above.

[0168] At this ratio, the silicone compound can appropriately interact with the conductive polymer, allowing a polymer layer of the desired shape to be effectively formed.

[0169] The polymer layer may also contain ceramic particles in addition to the components, and the surface of such ceramic particles may have an affinity for ions, thereby smoothly inducing ion migration and enabling efficient oxidation / reduction conversion.

[0170] The ceramic particles may be any known particles without any particular limitation, and may be, for example, metal oxide particles such as alumina, titania, or silica.

[0171] When the ceramic particles are used, the lower limit of the average particle size of the particles may be, for example, about 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, or 30 nm, and the upper limit may be about 1,000 nm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, 600 nm, 550 nm, 500 nm, 450 nm, 400 nm, 350 nm, 300 nm, 250 nm, 200 nm, 150 nm, 100 nm, 95 nm, 90 nm, 85 nm, 80 nm, 75 nm, 70 nm, 65 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm, or 30 nm. The average particle size may be within a range of less than or equal to any of the upper limits set forth above; or greater than or equal to any of the lower limits set forth above; or less than or equal to any of the upper limits set forth above, but greater than or equal to any of the lower limits set forth above. The average particle size is the median diameter, also known as the D50 particle size.

[0172] The ceramic particles may have any shape, such as spherical, rectangular, plate-like, or other amorphous shapes, as long as they have the above average particle size.

[0173] When the ceramic particles are used, the content of the ceramic particles in the polymer layer relative to 100 parts by weight of the conductive polymer may be about 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight, and the content of the ceramic particles in the polymer layer may be about 50 parts by weight, 48 parts by weight, 46 parts by weight, 44 parts by weight, 42 parts by weight, 40 parts by weight, 38 parts by weight, 36 parts by weight, 34 parts by weight, 32 parts by weight, 30 parts by weight, 28 parts by weight, 26 parts by weight, 24 parts by weight, 22 parts by weight, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, or 10 parts by weight. The content may be within a range that is less than or equal to any of the upper limits mentioned above; or within a range that is greater than or equal to any of the lower limits mentioned above; or within a range that is less than or equal to any of the upper limits mentioned above, but greater than or equal to any of the lower limits mentioned above.

[0174] The thickness of the polymer layer can be appropriately controlled depending on the purpose. For example, the lower limit of the thickness can be about 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 can be about 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 can be within a range equal to or less than any of the upper limits mentioned above; or within a range equal to or greater than any of the lower limits mentioned above; or within a range equal to or less than any of the upper limits mentioned above but equal to or greater than any of the lower limits mentioned above.

[0175] The thickness of the polymer layer can be measured by the method described in "3. Thickness Measurement" in the Examples section of this specification.

[0176] The polymer layer can exhibit suitable surface properties by exhibiting the above-mentioned properties, thereby ensuring excellent adhesion between layers in an electrode or current collector.

[0177] For example, the surface energy of the polymer layer in the current collector may be controlled within a predetermined range. For example, the lower limit of the surface energy may be about 25 mN / m, 30 mN / m, 35 mN / m, 40 mN / m, or 45 mN / m, and the upper limit may be about 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 equal to or less than any of the upper limits; or equal to or greater than any of the lower limits; or equal to or less than any of the upper limits but equal to or greater than any of the lower limits.

[0178] The present specification also discloses a method for manufacturing the current collector or electrode.

[0179] The method for manufacturing the current collector may include forming the polymer layer on the current collector body, and the method for manufacturing the electrode may include forming the active material layer on the polymer layer.

[0180] There is no particular limitation on the method for forming the polymer layer on the current collector body. For example, the polymer layer may be formed by preparing a coating solution by diluting the conductive polymer and, if necessary, other additives in an appropriate solvent, coating the coating solution on the current collector body, and then drying the coating solution.

[0181] In another example, the polymer layer may be formed by directly polymerizing a monomer that forms the conductive polymer on the current collector body.

[0182] The preparation and coating method of the coating composition for forming the polymer layer are not particularly limited, and known coating methods can be used. Furthermore, the method for polymerizing the conductive polymer is also not particularly limited, and known methods can be used. For example, methods using oxidative polymerization or radical reaction are typically known for preparing polythiophene, and these methods can also be used in the process of forming the conductive polymer in the present invention.

[0183] The prepared coating composition can be used to form a polymer layer on the current collector body. This process typically includes coating the coating composition on the current collector body and heat-treating the coated coating composition. During this process, the properties of the polymer layer can be controlled by the conditions of the heat treatment.

[0184] For example, the temperature T of the heat treatment and / or the time H of the heat treatment may be adjusted.

[0185] For example, the lower limit of the temperature T may be about 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, or 140°C, and the upper limit may be about 300°C, 295°C, 290°C, 285°C, 280°C, 275°C, 270°C, 265°C, 260°C, 255°C, 250°C, The temperature may be about 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., 130° C., 125° C., 120° C., 115° C., 110° C., 105° C., 100° C., 95° C., or 90° C. The temperature may be in a range that is less than or equal to any of the upper limits recited above; or in a range that is greater than or equal to any of the lower limits recited above; or in a range that is less than or equal to any of the upper limits recited above, but greater than or equal to any of the lower limits recited above. Within this range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0186] To achieve the objective, the product (T×H) of the heat treatment temperature T and the time H can be adjusted.For example, the lower limit of the product (T×H) of the heat treatment temperature T and the time H may be about 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, and the upper limit thereof may be about 100000 °C·hour, 95000 °C·hour, 90000 °C·hour, 85000 °C·hour, 80000 °C·hour, 75000 °C·hour, 70000 °C·hour, 65000 °C·hour, 60000 °C·hour, 55000 °C·hour, 50000 °C·hour, 45000 °C·hour, 40000 °C·hour, 35000 °C·hour, 30000 °C·hour, 25000 °C·hour, 20000 °C·hour, 15000 °C·hour, 10000 °C·hour, 9500 °C·hour, 9000 °C·hour, 8500 °C·hour, 8000 °C·hour, 7500 °C·hour, 7000 °C·hour, 6500 °C·hour, 6000 °C·hour, 5500 °C·hour, 5000 °C·hour, 4500 °C·hour, 4000 °C·hour, 3500 °C·hour, 3000 °C·hour, 2500 °C·hour, 2000 °C·hour, 1500 °C·hour, 1400 °C·hour, 1300 °C·hour, 1200 °C·hour, 1100 °C·hour, 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, 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, 10 °C·hour, 5 °C·hour, 4 °C·hour, 3 °C·hour, 2 °C·hour, 1 °C·hour or 0.5 °C·hour.The product (T×H) may be within a range of less than or equal to any of the upper limits mentioned above; or within a range of greater than or equal to any of the lower limits mentioned above; or within a range of less than or equal to any of the upper limits mentioned above and greater than or equal to any of the lower limits mentioned above. Within such a range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0187] To more effectively secure the desired properties, the heat treatment can be carried out in two stages.

[0188] For example, the heat treatment may include a step of first heat treating the coating composition at a first temperature T1 for a first time H1 and a step of second heat treating the coating composition at a second temperature T2 for a second time H2, wherein the temperatures T1 and T2 are different from each other and / or the times H1 and H2 are different from each other.

[0189] For example, the lower limit of the temperature T1 may be about 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, or 140°C, and the upper limit may be about 300°C, 295°C, 290°C, 285°C, 280°C, 275°C, The temperature may be about 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 equal to or less than any of the upper limits mentioned above; or within a range equal to or greater than any of the lower limits mentioned above; or within a range equal to or less than any of the upper limits mentioned above but equal to or greater than any of the lower limits mentioned above. Within this range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0190] For example, the lower limit of the product of the temperature T1 and the time H1 of the primary heat treatment (T1 x H1) may be about 0.01°C / hour, 0.05°C / hour, 0.1°C / hour, 0.2°C / hour, or 0.3°C / hour, and the upper limit may be about 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. The product (T1 × H1) may be about 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, 10°C / hour, 5°C / hour, 4°C / hour, 3°C / hour, 2°C / hour, 1°C / hour, or 0.5°C / hour. The product (T1 × H1) may be less than or equal to any of the upper limits mentioned above; or 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 but greater than or equal to any of the lower limits mentioned above. Within these ranges, the alignment of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring desired properties.

[0191] For example, the lower limit of the heat treatment temperature T2 of the second heat treatment may be about 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 the upper limit may be about 300°C, 295°C, 290°C, 285°C, 280°C, 275°C, 270°C, 285°C, 280°C, 295°C, 29 ... The temperature may be about 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 equal to or less than any of the upper limits mentioned above; or equal to or greater than any of the lower limits mentioned above; or within a range equal to or less than any of the upper limits mentioned above but equal to or greater than any of the lower limits mentioned above. Within this range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0192] The product of the second heat treatment temperature T2 and the 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 about 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 the upper limit may be about 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 product (T2 × H2) may be within a range of less than or equal to any of the above upper limits, or may be within a range of greater than or equal to any of the above lower limits, or may be within a range of less than or equal to any of the above upper limits but greater than or equal to any of the above lower limits. Within such a range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0193] In this case, the lower limit of the ratio T1 / T2 of the temperature T1 of the first heat treatment to the temperature T2 of the second heat treatment may be about 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 about 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 a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits. Within this range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring the desired properties.

[0194] In this case, the lower limit of the ratio H2 / H1 of the time H1 for the first heat treatment to the time H2 for the second heat treatment may be about 0.5, 1, 3, 5, 7, 9, 10, 11, 12, 13, 14, 14.5, or 15, and the upper limit may be about 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 a range equal to or less than any of the above upper limits; or within a range equal to or greater than any of the above lower limits; or within a range equal to or less than any of the above upper limits but equal to or greater than any of the above lower limits. Within this range, the alignment state of the hydrocarbon functional groups of the conductive polymer can be appropriately controlled, thereby ensuring desired properties.

[0195] In the manufacturing process, a post-process such as an appropriate drying process may be additionally performed following the coating and / or polymerization process.

[0196] In the manufacturing process, a post-process such as an appropriate drying process may be additionally performed following the coating and / or polymerization process.

[0197] There is no particular limitation 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 on a current collector (polymer layer), drying the coating, and then rolling the coating. Such a known method can be equally applied to the present invention.

[0198] Through the above process, the surface properties of the polymer layer are controlled, thereby ensuring excellent adhesive strength.

[0199] For example, the lower limit of the adhesive strength of the active material layer to the polymer layer or the current collector body in the electrode may be about 40 gf / 20 mm, 50 gf / 20 mm, 60 gf / 20 mm, 70 gf / 20 mm, 80 gf / 20 mm, 90 gf / 20 mm, 100 gf / 20 mm, 110 gf / 20 mm, 120 gf / 20 mm, 130 gf / 20 mm, or 140 gf / 20 mm, and the upper limit may be about 500 gf / 20 mm. The surface energy may be about 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 surface energy may be less than or equal to any of the upper limits mentioned above; or 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, but greater than or equal to any of the lower limits mentioned above.

[0200] The adhesive strength of the active material layer to the polymer layer or the current collector body means an adhesive strength that does not cause a phenomenon in which all or part of the active material layer is peeled off from the polymer layer, a phenomenon in which all or part of the polymer layer is peeled off from the current collector body, or other interfacial breakdown phenomena.

[0201] The present specification also relates to an electrode assembly or an electrochemical device, such as a secondary battery, that includes the electrode.

[0202] The electrochemical device may include the electrode as a positive electrode and / or a negative electrode. As long as the electrode is used as a negative electrode and / or a positive electrode, other configurations and manufacturing methods of the electrochemical device are not particularly limited, and known methods may be applied. [Effects of the Invention]

[0203] This specification discloses a current collector that exhibits excellent electrical properties, including low resistance under normal conditions, and ensures stability through increased resistance under abnormal conditions. This specification also discloses uses of the current collector. [Brief explanation of the drawings]

[0204] [Figure 1] 1 is an exemplary cross-sectional view of an electrode disclosed herein. [Figure 2] 1 shows the results of NMR analysis of the monomer of Production Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0205] Hereinafter, the current collectors disclosed in the present specification will be described in detail through examples and comparative examples, but the scope of the current collectors is not limited to the following examples.

[0206] 1.NMR analysis method 11H-NMR analysis was performed at room temperature using an NMR spectrometer that included a Bruker UltraShield spectrometer (300 MHz) with a triple resonance 5 mm probe. The sample was diluted in an NMR measurement solvent (CDCl3) to a concentration of approximately 10 mg / ml and used, and the chemical shift was expressed in ppm.

[0207] 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). The measurement conditions for GPC are as follows.

[0208] <GPC Measurement Conditions> Instrument: 2414 from Waters Columns: Three Styragel columns from Waters were used. Solvent: THF (Tetrahydrofuran) Column temperature: 35 °C Sample concentration: 1 mg / mL, 1 μL injection Standard sample: Polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

[0209] 3. Thickness measurement The thickness of the polymer layer was measured by cross-sectioning the electrode using an ion milling device (Hitachi, IM5000) and then taking images with a scanning electron microscope (SEM) (JEOL, JSM-7200F). The conditions for cross-section formation by ion milling were set as follows: the device was in cross-section milling mode, the speed (reciprocation / min) was 3, the acceleration voltage was 6.0 kV, the discharge voltage was 15 kV, the current was 150 μA, and the time was 4 hours.

[0210] 4. EIS (Electrochemical Impedance Spectroscopy) Conductivity (ohms) Evaluation Method The EIS conductivity of the polymer layer of the laminate, which had a current collector body and a polymer layer formed on the current collector body, was evaluated. In the examples and comparative examples, an active material layer was not formed on the polymer layer, and the EIS conductivity was measured with the polymer layer exposed. The EIS measurement device used was an electrochemical measuring instrument (potentiostat) (manufacturer: Princeton Applied Research, product name: PARASTAT-MC).

[0211] 5. Maximum resistance change rate measurement (EIS resistance) The following two types of coin cells were manufactured to measure the PTC (Positive Thermal Coefficient) temperature and maximum resistance value to confirm the PTC effect.

[0212] Coin cell 1: A polymer layer of approximately 10 μm thick was formed using a conductive polymer on an approximately 15 μm thick aluminum foil (current collector body). The polymer layer was formed using the method described in each corresponding example and comparative example, but to the above thickness. A separator and lithium film were then laminated on the polymer layer to produce a laminate of aluminum foil / polymer layer / separator / lithium film, which was then punched out into a circle with a diameter of approximately 1.4 cm. A coin cell was fabricated using the punched circular laminate and electrolyte (Welcos CR2032 coin cell kit). The separator used was a WL20C model from Double Scope Korea, the lithium film was a film with a thickness of about 100 μm, and the electrolyte was a 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate) manufactured by Enchem.

[0213] Coin cell 2: A coin cell was fabricated using a CR2032 coin cell kit (Welcos CR2032 coin cell kit). 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. The electrolyte was a carbonate-based electrolyte, a 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate), and the separator was a PE (poly(ethylene)) separator (WL20C model, Double Scope Korea).

[0214] The coin cell 1 or 2 was placed in the center of a convection oven (manufacturer: J.A.O.Tech, product name: OF3-05W). The oven temperature was set to an initial temperature of 25°C and a final temperature of 135°C, increasing by 5°C per minute. The coin cell was connected to an electrochemical measuring device (potentiostat) (Princeton Applied Research, PARASTAT-MC) outside the oven to measure EIS resistance. The EIS resistance was measured at each temperature increase (25°C, 30°C, 35°C, 40°C, increasing the temperature by 5°C up to 135°C). The highest resistance observed during this process and the temperature at which this maximum resistance was observed (PTC temperature) were also measured. The lowest resistance and the temperature at which this minimum resistance was observed were also measured.

[0215] 6.2C Capacity and Efficiency Measurement Coin cells were fabricated using a CR2032 coin cell kit (Welcos CR2032 coin cell kit). The electrodes fabricated in the examples and comparative examples were used as the positive electrode, and a lithium film (thickness: 100 μm) was used as the negative electrode. The electrolyte was a carbonate-based electrolyte, 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate), and the separator was a PE (poly(ethylene)) separator (WL20C model from Double Scope Korea).

[0216] The coin cell was charged / discharged once at 25°C to determine the capacity at 2 C. The coin cell was charged at a rate of 0.5 C using a CC (Constant Current) / CV (Constant Voltage) method with a charge cut-off voltage of 4.5 V and a charge cut-off current of 1 mA, and then discharged again at a rate of 2 C using a CC (Constant Current) method with a discharge cut-off voltage of 3.0 V, and the capacity was measured.

[0217] The discharge efficiency was evaluated by calculating the capacity value (A) when the battery was charged at a rate of 0.5C using the CC (constant current) / CV (constant voltage) method with a charge cut-off voltage of 4.5V and a charge cut-off current of 1mA, and then discharged again at a rate of 0.1C using the CC (constant current) method with the discharge cut-off voltage set to 3.0V. The capacity value (B) when the battery was charged at a rate of 0.5C using the CC (constant current) / CV (constant voltage) method with a charge cut-off voltage of 4.5V and a charge cut-off current of 1mA, and then discharged again at a rate of 2C using the CC (constant current) method with the discharge cut-off voltage set to 3.0V was calculated using the formula 100 x B / A.

[0218] Preparation Example 1. Synthesis of Monomer (A) The monomer of the following chemical formula C (monomer (A)) was synthesized by the following method.

[0219] [ka]

[0220] 1.372 g (12.02 mmol, 1 eq) of 3-methoxythiophene and 3 g (16.83 mmol, 1.4 eq) of triethylene glycol monomethyl ether were dissolved in 100 ml of toluene and mixed with 230 mg of p-toluenesulfonic acid (p-TsOH). The mixture was refluxed at 120°C, and the methanol produced during the transetherification was removed using a 4A-type molecular sieve filter loaded in a soxhlet extractor. After refluxing for 24 hours, the reaction mixture was quenched with water, extracted with ethyl acetate, washed with brine, and dried over magnesium sulfate (MgSO). The solvent was removed using a rotary evaporator, and the residue was purified by column chromatography eluting with methylene chloride / hexane (2:1) to obtain the target compound (monomer (A)). The NMR analysis results for the target compound (monomer (A)) are shown in Figure 2.

[0221] Production Example 2: Synthesis of polythiophene (A) To a solution of 3.20 g (19.71 mmol, 3 eq) of iron(III) chloride dissolved in 150 ml of methylene chloride, 0.787 g (3.12 mmol, 0.475 eq) of 3-dodecylthiophene, 0.525 g (3.12 mmol, 0.475 eq) of 3-hexylthiophene, and 0.083 g (0.3285 mmol, 0.05 eq) of monomer (A) from Preparation Example 1 were added and polymerized at 25°C for 24 hours to produce polythiophene (A). The polymerization solution was placed in a permeation membrane with a molecular weight of cut-off (MWCO) of 5000 and immersed in 200 ml of acetonitrile to remove unreacted iron chloride, monomer, and low molecular weight oligomers. The residue deposited inside the membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (A). The weight average molecular weight (Mw) and number average molecular weight (Mn) of polythiophene (A) were approximately 150,000 g / mol and 50,000 g / mol, respectively.

[0222] Preparation Example 3. Polydopamine-coated carbon fiber Carbon fibers were used, including VGCF (Vapor Grown Carbon Fiber) (VGCF™ product from Showa Denko). The VGCF had a cross-sectional diameter of approximately 150 nm and a length of approximately 10 μm. Polydopamine coating was performed on the carbon fibers as follows: Dopamine hydrochloride (CAS No. 62-31-7) was added to a buffer solution and stirred at room temperature (approximately 25°C). Biosesan's 0.1M pH 8.5 Tris-buffer solution was used as the buffer solution. The molar concentration of dopamine hydrochloride in the final solution was approximately 2 mg / mL. The VGCF was dispersed in a mixture of the buffer solution and dopamine hydrochloride at a concentration of about 4 mg / mL, and stirred for about 18 hours (sonicated for 1 hour) to form a polydopamine coating layer on the VGCF. The VGCF was then filtered under reduced pressure using a paper filter and dried in vacuo to obtain polydopamine-coated VGCF.

[0223] Example 1 A coating solution was prepared by dispersing polythiophene (A) from Preparation Example 2 and polydopamine-coated VGCF from Preparation Example 3 in a solvent (Chloroform) at a weight ratio of 10:1 (A:VGCF). The coating solution was coated onto a current collector body using a bar coating method (#8 Meyer bar) and maintained at 140°C for approximately 4 minutes and then at 130°C for approximately 1 hour to form a layer (polymer layer) with a thickness of approximately 400 nm. An aluminum foil with a thickness of approximately 15 μm was used as the current collector body. An active material layer was then formed on the polymer layer. The active material layer was formed by coating a slurry containing lithium cobalt oxide (LiCoO2), carbon-based conductive materials (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) onto the polymer layer with a doctor blade to a thickness of approximately 90 μm. The slurry was then dried at room temperature and further dried under vacuum at 120°C. The electrode was then rolled to a porosity of approximately 25%.

[0224] Example 2. An electrode was fabricated in the same manner as in Example 1, except that the coating was performed twice to make the polymer layer thickness about 700 nm.

[0225] Example 3 A coating solution was prepared by dispersing polythiophene (A) from Preparation Example 2 and polydopamine-coated VGCF from Preparation Example 3 in a solvent (Chloroform) at a weight ratio of 10:1 (A:VGCF). The coating solution was coated onto a current collector body using a bar coating method (#8 Meyer bar) and maintained at 80°C for approximately 10 minutes to form a layer (polymer layer) with a thickness of approximately 400 nm. An aluminum foil with a thickness of approximately 15 μm was used as the current collector body. Subsequently, an active material layer was formed on the polymer layer. The active material layer was formed by coating a slurry containing lithium cobalt oxide (LiCoO2), carbon-based conductive materials (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) onto the polymer layer with a doctor blade to a thickness of approximately 90 μm. The slurry was then dried at room temperature and further dried under vacuum at 120°C. The electrode was then rolled to a porosity of approximately 25%.

[0226] Comparative Example 1 A coating solution was prepared by dispersing polythiophene (A) from Preparation Example 2 in a solvent (chloroform). The coating solution was coated onto the current collector body using a bar coating method (#8 Meyer bar) and maintained at 140°C for about 4 minutes, and then at 130°C for about 1 hour to form a layer (polymer layer) with a thickness of about 400 nm. An aluminum foil with a thickness of about 15 μm was used as the current collector body. Subsequently, an active material layer was formed on the polymer layer. The active material layer was formed by coating a slurry containing lithium cobalt oxide (LiCoO2), carbon-based conductive materials (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) onto the polymer layer with a doctor blade to a thickness of approximately 90 μm. The slurry was then dried at room temperature and further dried under vacuum at 120°C. The electrode was then rolled to a porosity of approximately 25%.

[0227] Comparative Example 2 An electrode was fabricated in the same manner as in Comparative Example 1, except that the coating was performed twice to make the polymer layer thickness about 700 nm.

[0228] The measurement results for the prepared electrodes are summarized in Table 1 below.

[0229] [Table 1]

Claims

1. a current collector body; and a polymer layer formed on the current collector body, The polymer layer comprises a conductive polymer and a conductive material.

2. The current collector according to claim 1 , wherein the content of the electrode active material in the polymer layer is 10 wt % or less.

3. 2. The current collector according to claim 1, wherein the conductive polymer comprises a first thiophene unit having a hydrocarbon functional group with 10 or more carbon atoms and a second thiophene unit having a hydrocarbon functional group with 9 or less carbon atoms.

4. 4. The current collector of claim 3, wherein the hydrocarbon functional group is a straight or branched chain alkyl, alkenyl, or alkynyl group.

5. 4. The current collector according to claim 3, wherein the hydrocarbon functional group of the first thiophene unit has a carbon number of 10 to 20 in the range, and the hydrocarbon functional group of the second thiophene unit has a carbon number of 3 to 9 in the range.

6. 4. The current collector according to claim 3, wherein the conductive polymer contains 80 mol% or more of thiophene units having a hydrocarbon functional group with 10 or more carbon atoms and 80 mol% or more of thiophene units having a hydrocarbon functional group with 9 or less carbon atoms.

7. 4. The current collector according to claim 3, wherein a 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 is in the range of 0.01 to 100.

8. 4. The current collector of claim 3, 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: 【Chemical 1】 In Chemical Formula 1, R １ and R ２ are each independently hydrogen or a hydrocarbon functional group having 10 or more carbon atoms, but R １ and R ２ At least one of the hydrocarbon functional groups having 10 or more carbon atoms is １ and R ２ are linked together to form a divalent functional group of formula 2: 【Chemistry 2】 In chemical formula 2, L １ and L ２ are each independently a single bond, an alkylene group, or an alkylidene group, and R ３ and R ４ are each independently hydrogen or the hydrocarbon functional group having 10 or more carbon atoms, but R ３ and R ４ at least one of which is a hydrocarbon functional group having 10 or more carbon atoms: 【Chemistry 3】 In chemical formula 3, R ５ and R ６ are each independently hydrogen or a hydrocarbon functional group having 9 or less carbon atoms, but R ５ and R ６ At least one of the hydrocarbon functional groups having 9 or less carbon atoms is ５ and R ６ are linked together to form a divalent functional group of formula 4: 【Chemistry 4】 In chemical formula 4, L ３ and L ４ are each independently a single bond, an alkylene group, or an alkylidene group, and R ７ and R ８ are each independently hydrogen or the hydrocarbon functional group having 9 or less carbon atoms, but R ７ and R ８ At least one of the groups is a hydrocarbon functional group having 9 or less carbon atoms.

9. The current collector of claim 3 , wherein the conductive polymer additionally comprises a third thiophene unit having a polar functional group.

10. 10. The current collector according to claim 9, wherein the polar functional group is a carboxy group, a hydroxy group, an amino group, a cyano group, a nitro group, an ether group, or a functional group of the following chemical formula 5: 【Chemistry 5】 L in Chemical Formula 5 ５ is a single bond, an alkylene group, or an alkylidene group, and L ６ is an alkylene group or an alkylidene group, and R ９ is hydrogen or an alkyl group, and n is a number in the range of 1 to 10.

11. 10. The current collector of claim 9, wherein the third thiophene unit is represented by the following formula 6: 【Chemistry 6】 In chemical formula 6, R １０ and R １１ are each independently hydrogen or a polar functional group, but R １０ and R １１ At least one of the polar functional groups is a polar functional group, or R １０ and R １１ are linked together to form a divalent functional group of formula 7: 【Chemistry 7】 In chemical formula 7, L ７ and L ８ are each independently a single bond, an alkylene group, or an alkylidene group, and R １２ and R １３ are each independently hydrogen or the polar functional group, but R １２ and R １３ At least one of the groups is the polar functional group.

12. 10. The current collector of claim 9, wherein the third thiophene unit in the conductive polymer is contained in an amount such that 1 mole to 500 moles of the first and second thiophene units are present per mole of the third thiophene unit.

13. The current collector according to claim 1 , wherein R in the following formula A is 100 or more: [Formula A] R=R ＭＡＸ / R ＭＩＮ Formula A and R ＭＡＸ is the maximum EIS resistance of the polymer layer observed in the temperature range of 25°C to 135°C, and R ＭＩＮ is the minimum EIS resistance of the polymer layer observed in the temperature range of 25°C to 135°C.

14. R ＭＡＸ 14. The current collector of claim 13, wherein the resistance is 9,000 ohms or greater.

15. R ＭＡＸ is confirmed within the range of 80°C to 135°C, and R ＭＩＮ The current collector according to claim 13, wherein the temperature at which the above is confirmed is within a range of 25°C to 80°C.

16. 2. The current collector of claim 1, wherein the conductive material is carbon particles, carbon fibers, graphene, graphite, carbon black, or carbon nanotubes.

17. The current collector according to claim 1 , wherein the conductive material is surface-treated with a polyphenol-based compound.

18. A current collector according to any one of claims 1 to 17; and an electrode comprising an active material layer formed on the polymer layer of the current collector;

19. 20. An electrode assembly comprising the electrode of claim 18.

20. A secondary battery comprising the electrode according to claim 18.

Images