Electrode

Abstract

The present specification discloses an electrode and a use thereof. The electrode includes a polymer layer that exhibits a so-called PTC (Positive Temperature Coefficient) effect at a desired level at a desired time, whereby it can be suitably applied in applications in which stability problems are caused by abnormally high heat or flames. The polymer layer can exhibit oxidation potential characteristics suitable for electrode applications, and can stably maintain such oxidation potential characteristics even in harsh environments. In the polymer layer of the electrode, the PTC effect can occur rapidly at a required time. The present specification also discloses a use of the electrode.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0108455, filed on August 18, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This specification discloses an electrode and its application. Background Technology

[0003] Energy storage technology has expanded its applications to mobile phones, tablets, laptops, and electric vehicles.

[0004] With the increasing data processing speed of mobile devices such as smartphones or tablets and their extended usage time, secondary batteries with high energy density and operating potential, long cycle life and low self-discharge rate are being developed.

[0005] As major developed countries curb the production of internal combustion engine-powered vehicles to mitigate global warming and air pollution, major automakers have also developed various electric vehicles. As a result, the importance of secondary batteries with high energy density, high discharge voltage, and output stability as their power source has increased.

[0006] Based on the above trends, the frequency of fires or explosions caused by overcharging, high-temperature exposure, or external impacts is also increasing in devices or vehicles that use secondary batteries as an energy source.

[0007] The known cause of such accidents is short circuits, where the positive and negative electrodes within the electrode assembly come into direct contact with each other primarily due to external stimuli. Short circuits can occur when a secondary battery is overcharged or exposed to high temperatures or external stimuli, due to diaphragm shrinkage caused by increased internal temperature or damage to the internal structure caused by external impacts.

[0008] When a short circuit occurs, lithium ions and electrons concentrate in the area where the positive and negative electrodes are in direct contact, which promotes internal heating. Therefore, it is known that as gases and other substances are generated inside the battery, the volume expands, increasing the risk of fire. Summary of the Invention

[0009] Technical issues This specification discloses an electrode and its applications. One object of this specification is to disclose an electrode with an applied polymer layer that ensures stability in applications where stability issues arise due to abnormally high heat or flame by exhibiting a so-called PTC (positive temperature coefficient) effect at a desired level and for a desired time. Another object of this specification is to disclose an electrode comprising a polymer layer that exhibits oxidation potential characteristics suitable for the application and stably maintains these oxidation potential characteristics even in harsh environments. Yet another object of this specification is to disclose an electrode comprising a polymer layer in which the PTC effect rapidly occurs at a desired level and for a desired time. A further object of this specification is to disclose one application of said electrode.

[0010] Technical solution In this specification, the term room temperature refers to the natural temperature without artificial heating or cooling. Room temperature can be, for example, any temperature in the range of 10°C to 30°C, or around 23°C, 25°C, or 27°C.

[0011] Unless otherwise specified, the physical properties mentioned in this specification that are affected by the measurement temperature are those measured at room temperature.

[0012] Unless otherwise specified, the temperature unit in this instruction manual is degrees Celsius (°C).

[0013] In this specification, the term atmospheric pressure refers to natural pressure without artificial pressurization or depressurization, wherein pressure in the range of approximately 730 mmHg to 790 mmHg can generally be considered atmospheric pressure.

[0014] Unless otherwise specified, the physical properties mentioned in this specification that are affected by the measurement pressure are those measured at normal pressure.

[0015] In this specification, standard state humidity refers to any relative humidity in the range of 40% to 60%, where, for example, relative humidity of about 40%, 45%, 50%, 55% or 60% can be referred to as standard state humidity.

[0016] Unless otherwise specified, the physical properties mentioned in this specification that are affected by the measured humidity are those measured under standard humidity conditions.

[0017] In this specification, the term normal state refers to the normal operating state (e.g., the normal charging or discharging state of a secondary battery) and / or storage state of an electrical / electronic device such as a secondary battery.

[0018] In this specification, the term "abnormal state" refers to a state in which abnormal heating, fire, and / or explosion occurs in electrical / electronic equipment such as a secondary battery, or a state in which the risk of abnormal heating, fire, and / or explosion increases. For example, a state in which abnormal heating, fire, or explosion occurs due to a short circuit in a secondary battery, or a dangerous state in which the possibility of heating, fire, or explosion increases, can be considered an abnormal state.

[0019] This specification discloses an electrode.

[0020] The electrode may include a current collector and an electrode active material layer formed on the current collector. The electrode may further include a polymer layer located between the current collector and the electrode active material layer. Figure 1 It is a schematic cross-sectional view of an electrode including a current collector 100, a polymer layer 200, and an electrode active material layer 300.

[0021] In the electrode, the current collector 100 and the polymer layer 200, as well as the polymer layer 200 and the electrode active material layer 300, can be in contact with each other. In some cases, other elements may be present between the current collector 100 and the polymer layer 200, or between the polymer layer 200 and the active material layer 300. Furthermore, although the figures show the active material layer 300 present only on one side of the current collector 100, the active material layer 300 may also be present on both sides of the current collector 100. In this case, the polymer layer 200 may exist as two layers between each active material layer 300 on both sides of the current collector 100 and the current collector 100, or it may exist as a single layer between any one of the active material layers 300 on either side of the current collector 100 and the current collector 100.

[0022] The electrode can be, for example, the positive electrode (anode) or negative electrode (cathode) of a secondary battery.

[0023] The polymer layer exhibits a so-called PTC (positive temperature coefficient) effect. Therefore, the polymer layer can variably control the movement of charge through the electrodes according to temperature.

[0024] By applying this polymer layer, electrodes can be used in secondary batteries and other applications, thereby exhibiting excellent electrical properties, including low resistance under normal conditions and stability through increased resistance under abnormal conditions.

[0025] To apply the polymer layer to the electrode and achieve the aforementioned effects, it is essential to control the oxidation potential of the polymer layer and the tendency of the PTC effect exhibited by the polymer layer. The PTC effect is an effect where resistance increases proportionally with temperature. The temperature at which the resistance increases due to the PTC effect, as well as the resistance of the polymer layer before the increase, affect the performance of the secondary battery. For example, if the PTC effect is overexpressed at normal operating temperatures, the performance of the secondary battery cannot be properly expressed until stability is ensured. Furthermore, if the oxidation potential of the polymer layer is not properly controlled relative to the electrode active material, performance degradation of the battery under normal conditions can occur.

[0026] The polymer layer exhibits a PTC effect, and the oxidation potential of the polymer layer with this PTC effect and the PTC effect do not affect the performance of the secondary battery under normal conditions, and are regulated to ensure stability under abnormal conditions.

[0027] As described below, conductive polymers contain unique functional groups, such as relatively long-chain hydrocarbon functional groups, non-thiophene monomer units, and thiophene monomer units. By controlling the drying or annealing temperature during the formation of a polymer layer containing such a conductive polymer and conductive material, a proper PTC effect can be ensured, for example, inducing an increase in the resistance of the polymer layer at a desired temperature (the temperature of an abnormal state in the battery).

[0028] In one example, the polymer layer applied to the electrode may have a lower oxidation potential than the electrode active material layer (or the electrode active material contained within the electrode active material layer). Unless otherwise stated, the oxidation potentials mentioned in this specification are based on Li / Li + The oxidation potential is measured in accordance with the manner described in the Examples section of this specification. The oxidation potential varies depending on the electrode and electrolyte used for measurement, wherein the oxidation potential in this specification is based on lithium and lithium ions (Li / Li). + The oxidation potential was measured.

[0029] The oxidation potential mentioned in this specification is based on Li / Li + The oxidation potential is measured in accordance with the manner described in "4. Measurement of Oxidation Potential (Polymer Layer)" or "5. Measurement of Oxidation Potential (Electrode Active Material)" in the Examples section of this specification.

[0030] In one example, the oxidation potential of the polymer layer in the electrode can be controlled such that ΔV is within a predetermined range according to Equation 1 below.

[0031] [Equation 1] ΔV = 100 × (Va - Vs) / Va In Equation 1, Va is the oxidation potential of the active material layer or the electrode active material contained therein, and Vs is the oxidation potential of the polymer layer.

[0032] In Equation 1, the lower limit of ΔV can be approximately 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%, and its upper limit can be approximately %, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, or 4.5%. ΔV can be greater than or equal to any lower limit selected from the list above; or greater than or equal to any lower limit selected from the list above, while being less than or equal to any upper limit selected from the list above. By controlling the oxidation potential of the polymer layer to satisfy the aforementioned relationship, a battery that operates stably and effectively under normal conditions can be provided.

[0033] If the above relationship is satisfied, there are no particular restrictions on the oxidation potential of the polymer layer. The lower limit of the oxidation potential (Vs) of the polymer layer can be around 2V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V, or 3.7V, and the upper limit can be around 6V, 5.5V, 5V, 4.9V, 4.8V, 4.7V, 4.6V, 4.5V, 4.4V, 4.3V, 4.2V, 4.1V, 4.0V, 3.9V, 3.8V, 3.7V, 3.6V, or 3.5V. The oxidation potential can be less than or equal to or less than any upper limit chosen from the upper limits listed above; or it can be greater than or equal to or greater than any lower limit chosen from the lower limits listed above, while being less than or equal to or less than any upper limit chosen from the upper limits listed above.

[0034] In one example, the polymer layer or the electrode onto which the polymer layer is applied can have a DC resistance below a certain level at 25°C. Therefore, the secondary battery can operate or be stored stably under normal conditions. The upper limit of a DC resistor can be around 10,000, 9500, 9000, 8500, 8000, 7500, 7000, 6500, 6000, 5500, 5000, 4500, 4000, 3500, 3000, 2500, 2000, 1500, 1000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 90, 80, 70, or 60, while the lower limit can be around 5, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, or 600. The DC resistance can be less than or equal to, or less than, any upper limit chosen from the list of upper limits above; or greater than or equal to, or greater than, any lower limit chosen from the list of lower limits above, while being less than or equal to, or less than, any upper limit chosen from the list of upper limits above. The unit of DC resistance is Ω·cm, and it is measured in accordance with the method described in "6. DC Resistance Measurement Method" of the Embodiments section of this specification.

[0035] In one example, the polymer layer or polymer layer electrode can have an AC impedance resistance below a certain level at 25°C. Therefore, the secondary battery can operate or be stored stably under normal conditions. The upper limit of the AC impedance resistance can be approximately 1,000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, or 7, and its lower limit can be approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The AC impedance resistance can be less than or equal to any upper limit chosen from the upper limits listed above; or greater than or equal to any lower limit chosen from the lower limits listed above, while being less than or equal to or less than any upper limit chosen from the upper limits listed above. The unit of AC resistance is Ω, which is measured in accordance with the method described in "7. AC Impedance Resistance" of the Embodiments section of this specification.

[0036] By exhibiting DC resistance and / or AC impedance resistance, the secondary battery with the electrodes applied can operate and be stored stably under normal conditions.

[0037] The electrode is applied to the battery, thereby exhibiting increased resistance under abnormal conditions, and stability can be ensured by blocking the power supply to the electrode assembly.

[0038] The polymer layer or the electrode with the polymer layer can exhibit the characteristic that ΔR1 is above a certain level as shown in Equation 2 below.

[0039] [Equation 2] ΔR1 = Max{(R n+5 / R n ) / 5} In equation 2, R n R is the DC resistance at any temperature n℃ within the range of 25℃ to 135℃. n+5 The DC resistance at a temperature 5°C higher than temperature n°C ((n+5)°C), Max{(R n+5 / R n ) / 5} was confirmed within the temperature range of 25℃ to 135℃ (R n+5 / R n The maximum value among 5.

[0040] The method for measuring ΔR1 in Equation 2 is described in section 8. Measurement of Maximum Rate of Resistance Change (DC Resistance) of the Examples section. In the above method for confirming ΔR1, the initial temperature is 25°C and the final temperature is 135°C. n+5 and R n This was confirmed by measuring the DC resistance at each temperature while increasing the temperature by 5°C from an initial temperature of 25°C. For example, when n is 90, R... 95 / R 90 It is the ratio of the DC resistance at 95℃ to the DC resistance at 90℃. The fact that ΔR1 exhibits a certain level or above at any temperature within the temperature range of 25℃ to 135℃ means that the resistance increases relatively rapidly at any temperature within that temperature range.

[0041] The lower limit of ΔR1 can be 10, 50, 100, 110, 120, 130, 140, 150, 160, 170, 180, or 190, and its upper limit can be approximately 1,000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 190, or 180. The unit of ΔR1 is Ω·cm / ℃. ΔR1 can be greater than or equal to any lower limit chosen from the lower limits listed above; or less than or equal to any upper limit chosen from the upper limits listed above, while being greater than or equal to any lower limit chosen from the lower limits listed above.

[0042] Confirm the temperature of ΔR1 within the specified range, i.e., R in Equation 2. n The temperature can be a range. This temperature range is crucial for ensuring the stable operation and stability of the secondary battery. That is, if the temperature falls within the normal operating range of the secondary battery, then a temperature rise at the relevant temperature will adversely affect the performance of the secondary battery. R in Equation 2 above... n The lower limit of the temperature can be approximately 70℃, 75℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, or 95℃, and the upper limit can be approximately 200℃, 190℃, 180℃, 170℃, 160℃, 150℃, 140℃, 130℃, 120℃, 110℃, 100℃, or 90℃. The temperature can be greater than or equal to or greater than any lower limit chosen from the list of lower limits; or less than or equal to or less than any upper limit chosen from the list of upper limits, while being greater than or equal to or greater than any lower limit chosen from the list of lower limits.

[0043] By controlling the increase in resistance within the stated temperature range, stable operation and storage under normal conditions, as well as stable interruption of power supply under abnormal conditions, can be achieved. For example, by adjusting the temperature range, stable storage can be achieved even when the secondary battery is stored at a relatively high temperature.

[0044] The polymer layer and the current collector or electrode using the polymer layer can exhibit the characteristic that ΔR2 is above a certain level as shown in Equation 3 below.

[0045] [Equation 3] ΔR² = Max{(R z+5 / R z ) / 5} In equation 3, R z R is the AC impedance resistance at any temperature n℃ within the range of 25℃ to 135℃. z+5 The AC impedance resistance at a temperature 5°C higher than temperature n°C ((n+5)°C), Max{(R z+5 / R z ) / 5} was confirmed within the temperature range of 25℃ to 135℃ (R z+5 / R z The maximum value among 5.

[0046] The method for measuring ΔR² in Equation 3 is described in section 9. Measurement of Maximum Rate of Change of Resistance (AC Impedance) of the Examples section. In the above method for confirming ΔR², the initial temperature is 25°C and the final temperature is 135°C. R² is confirmed by measuring the AC impedance resistance at each temperature while simultaneously increasing the temperature by 5°C from the initial temperature of 25°C. z+5 and R z For example, when n is 90, R 95 / R 90 It is the ratio of the AC impedance resistance at 95°C to the AC impedance resistance at 90°C. The fact that ΔR2 is greater than 10 Ω / °C at any temperature in the temperature range of 25°C to 135°C means that the resistance of the polymer layer or electrode increases relatively rapidly at any temperature within this temperature range.

[0047] The lower limit of ΔR² can be approximately 5, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, or 33, and its upper limit can be approximately 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, or 20. The unit of ΔR² is Ω / ℃. The range of ΔR² can be greater than or equal to any lower limit chosen from the listed lower limits; or less than or equal to any upper limit chosen from the listed upper limits, while being greater than or equal to any lower limit chosen from the listed lower limits.

[0048] By ensuring these characteristics, an increase in resistance can be exhibited under abnormal conditions, and stability can be ensured by blocking the current flow.

[0049] Similar to the case of equations, confirm the temperature of ΔR2, i.e., R z The temperature range is very important. The lower limit of the temperature can be approximately 70℃, 75℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, or 95℃, and the upper limit can be approximately 200℃, 190℃, 180℃, 170℃, 160℃, 150℃, 140℃, 130℃, 120℃, 110℃, 100℃, or 90℃. The temperature can be greater than or equal to or greater than any lower limit chosen from the list above; or less than or equal to or less than any upper limit chosen from the list above, while being greater than or equal to or greater than any lower limit chosen from the list above.

[0050] By controlling the increase in resistance within the stated temperature range, stable operation and storage are possible under normal conditions, and stable power supply can be blocked under abnormal conditions. For example, by adjusting the temperature range, stable storage is possible even when the secondary battery is stored at a relatively high temperature.

[0051] The polymer layer and the current collector or electrode using the polymer layer can exhibit characteristics where the absolute value of ΔR3 in Equation 4 below is within a certain range.

[0052] [Equation 3] ΔR3 = 100 × (C1-C2) / C1 In Equation 4, C1 is the discharge capacity at room temperature (approximately 25°C), and C2 is the discharge capacity after storage at 70°C for 60 hours. C1 and C2 in Equation 4 represent the discharge capacity of the polymer layer measured for a button cell, and the specific method for measuring it is summarized in the examples.

[0053] In Equation 4, the upper limit of the absolute value of ΔR3 can 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%, while the lower limit can be approximately 0%, 0.5%, or 1.5%. The absolute value of ΔR3 can be less than or equal to, or less than, any upper limit chosen from the list above; or it can be less than or equal to, or less than, any upper limit chosen from the list above, while being greater than or equal to, or greater than, any lower limit chosen from the list above. The ΔR3 within the above range refers to the range under normal conditions, indicating that the secondary battery can operate and be stored stably even when operating and stored at relatively high temperatures.

[0054] The polymer layer, the current collector or electrode using the polymer layer can exhibit the characteristic that the absolute value of ΔR4 in Equation 5 is greater than 50%.

[0055] [Equation 5] ΔR4 = 100 × (C 25 -C 130 ) / C 25 In Equation 5, C1 is the discharge capacity at room temperature (approximately 25°C), and C3 is the discharge capacity after storage at 130°C for 10 minutes.

[0056] C1 and C3 in Equation 5 are the discharge capacities measured for coin cells with the polymer layer applied, and the specific measurement methods are summarized in Section 11, High Temperature Discharge Capacity Reduction Rate, of the Examples section.

[0057] In Equation 5, the lower limit of the absolute value of ΔR4 can be approximately 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, or 88%, and its upper limit can be approximately 200%, 180%, 160%, 140%, 120%, 100%, 95%, 90%, 85%, or 80%. The absolute value of ΔR4 can be greater than or equal to any lower limit chosen from the list above; or it can be less than or equal to any upper limit chosen from the list above, while being greater than or equal to any lower limit chosen from the list above. Within the above range, ΔR4 refers to the ability to effectively ensure stability by increasing resistance under abnormal conditions of the secondary battery.

[0058] These properties can be achieved by introducing the polymer layer described below.

[0059] As a current collector, a current collector that is typically used as a positive or negative electrode can be used.

[0060] There are no particular restrictions on the type, size, and shape of the current collector if it is conductive and does not cause chemical changes in applications such as secondary batteries. Examples of materials that can be used as current collectors include materials with surfaces of copper, aluminum, or stainless steel treated with carbon, nickel, titanium, or silver. Current collectors can be in the form of films, sheets, foils, meshes, porous bodies, foams, or nonwoven fabrics containing the aforementioned materials. In some cases, known surface treatments can be applied to the surface of the current collector to improve adhesion to other layers such as polymer layers or active material layers.

[0061] Such current collectors can typically have a thickness ranging from 3 μm to 500 μm, but are not limited to this.

[0062] The polymer layer exists on one or both sides of the current collector.

[0063] The term "polymer layer" refers to a layer containing a polymer. The lower limit of the polymer content in the polymer layer can be approximately 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight, or 95% by weight, and the upper limit can be approximately 100% by weight, 95% by weight, 90% by weight, 85% by weight, 80% by weight, 75% by weight, 70% by weight, 65% by weight, 60% by weight, 55% by weight, or 50% by weight. This content is the weight of the polymer based on the total weight of the polymer layer. This content can be greater than or equal to or greater than any lower limit chosen from the lower limits listed above; or greater than or equal to or greater than any lower limit chosen from the lower limits listed above, while being less than or equal to or less than any upper limit chosen from the upper limits listed above.

[0064] The polymer layer does not necessarily have to be a so-called electrode active material layer. The content of electrode active material in the polymer layer can be controlled. For example, the upper limit of the content of electrode active material in the polymer layer can be approximately 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, 0.005 wt%, or 0.001 wt%, and the lower limit can be 0 wt%. This content is the content of electrode active material based on the total weight of the polymer layer. This content can be less than or equal to or less than any upper limit chosen from the upper limits listed above; or it can be greater than or equal to or greater than the lower limit mentioned above, while being less than or equal to or less than any upper limit chosen from the upper limits mentioned above.

[0065] The polymer layer may contain a conductive polymer. Conductive polymers are known to exhibit conductivity through conjugated polymer chains and / or doping. For example, a conductive polymer is one that exhibits low resistance in a doped state and high resistance in a dedoped state; it can be a polymer designed such that the transition between the doped and dedoped states can occur rapidly in response to temperature and / or voltage at necessary time points.

[0066] The polymer layer may need to exhibit an appropriate level of oxidation potential depending on the application. For example, when the polymer layer is located between the current collector and the active material layer, as in an electrode, the polymer layer may need to exhibit a lower oxidation potential than the active material layer, and this low oxidation potential needs to be maintained even during repeated charge / discharge and / or high-speed charge / discharge of the secondary battery. Otherwise, a potential drop may occur during repeated charge / discharge and / or high-speed charge / discharge.

[0067] The thickness of the polymer layer can be appropriately controlled according to the purpose. For example, the lower limit of the polymer layer thickness can be approximately 10nm, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, or 400nm, and its upper limit can be approximately 2μm, 1.5μm, 1μm, 950nm, 900nm, 850nm, 800nm, 750nm, 700nm, 650nm, 600nm, 550nm, 500nm, 450nm, or 400nm. The thickness can be less than or equal to any upper limit chosen from the above-listed upper limits, while being greater than or equal to or greater than any lower limit chosen from the above-listed lower limits.

[0068] The conductive polymer contained in the polymer layer can be a thiophene polymer.

[0069] The term thiophene polymer refers to a polymer containing a certain level or higher of thiophene monomer units.

[0070] For example, the lower limit of the molar percentage of thiophene monomer units in a thiophene polymer can be approximately 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, or 80 mol%, while the upper limit can be approximately 100 mol%, 95 mol%, 90 mol%, or 80%. The molar percentage of thiophene monomer units is the total molar number of all thiophene monomer units present in the thiophene polymer (M). T ) or the number of moles of all thiophene monomers used to prepare the thiophene polymer (M) T The ratio of the number of moles (M) of all monomer units present in the thiophene polymer to the number of moles (M) of all monomers used to prepare the thiophene polymer (100×M). T / M). The proportion of thiophene monomer units (100×M) T / M) can be within a range that is greater than or equal to or greater than any lower limit chosen from the lower limits listed above; or within a range that is less than or equal to or less than any upper limit chosen from the upper limits listed above, while being greater than or equal to or greater than any lower limit chosen from the lower limits listed above.

[0071] The term monomer unit refers to the form in which a monomer is polymerized and contained within a polymer molecule (polymer). The term thiophene monomer refers to thiophene monomers, which are monomers containing a thiophene backbone.

[0072] The conductive polymer may contain long-chain hydrocarbon functional groups or monomer units with long-chain hydrocarbon functional groups (hereinafter referred to as Unit A). Unit A may be a thiophene monomer unit.

[0073] The term long-chain hydrocarbon functional group refers to a monovalent hydrocarbon group having a certain number of carbon atoms or more, or a monovalent functional group containing such a monovalent hydrocarbon group.

[0074] For example, the lower limit for the number of carbons present in the functional group of a long-chain hydrocarbon (i.e., the number of carbons in the monovalent hydrocarbon group) can be approximately 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, and the upper limit can be approximately 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, or 4. The number of carbons can be greater than or equal to or greater than any lower limit chosen from the lower limits listed above; or greater than or equal to or greater than any lower limit chosen from the lower limits listed above, while being less than or equal to or less than any upper limit chosen from the upper limits listed above.

[0075] The carbon number can be the total number of carbons present in the functional groups of a long-chain hydrocarbon, or the number of carbons in the straight-chain hydrocarbon chain of the functional group. That is, the monovalent hydrocarbon group present in the functional group of the long-chain hydrocarbon can have a straight-chain or branched structure. When the monovalent hydrocarbon group has a straight-chain structure, the number of carbons in the straight-chain structure can be within the aforementioned range. When the monovalent hydrocarbon group has a branched structure, the number of carbons in the longest straight chain constituting the relevant branched structure can be within the aforementioned range. For example, if the branched structure is 2-ethylhexyl, then the number of carbons constituting the longest straight chain is 6.

[0076] An example of a long-chain hydrocarbon functional group may be exemplified as one or more selected from alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, and alkylcarbonyloxy. In a suitable example, the long-chain hydrocarbon functional group may be alkyl and / or alkoxy.

[0077] The number of carbon atoms present in alkyl, alkenyl, alkynyl, alkoxy, alkyl carbonyl, and alkyl carbonyloxy groups can be within the range of the number of carbon atoms present in long-chain hydrocarbon functional groups (i.e., the number of carbon atoms in monovalent hydrocarbon groups).

[0078] Alkyl, alkenyl, alkynyl, alkoxy, alkyl carbonyl, and alkyl carbonyloxy can be straight-chain or branched structures. In the case of branching, the number of carbon atoms in the longest straight chain constituting the relevant branched structure can be within the range described above.

[0079] Alkyl, alkenyl, alkoxy, alkyl carbonyl, or alkyl carbonyloxy groups, which are long-chain hydrocarbon functional groups, may also be optionally substituted by one or more substituents.

[0080] Long-chain hydrocarbon functional groups can exhibit enhanced vibrational energy at elevated temperatures. This enhanced vibrational energy can influence the doping and dedoping states of conductive polymers. The degree of vibrational energy and the temperature at which it occurs are influenced by the carbon number and arrangement of the long-chain hydrocarbon functional groups. Therefore, by adjusting the carbon number and amount of the long-chain hydrocarbon functional groups and regulating their arrangement using the manufacturing method described below, the desired properties of the polymer layer can be ensured. For example, at the same temperature, the vibrational energy of relatively long chains is greater than that of relatively short chains. Therefore, by appropriately applying long and short chains as long-chain hydrocarbon functional groups, conductive polymers that meet the desired effects can be provided.

[0081] Incidentally, long-chain hydrocarbon functional groups can provide appropriate flowability to monomers or polymers during the polymerization of conductive polymers, thus improving polymerization efficiency.

[0082] For example, the molar number (M) of long-chain hydrocarbon functional groups can be adjusted. L The ratio of the molar number of monomer units (unit A) having the functional group to the total molar number of monomer units (M) of the conductive polymer. For example, the lower limit of this ratio can be approximately 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, or 70 mol%, and the upper limit can be approximately 95 mol%, 90 mol%, 85 mol%, 80 mol%, or 75 mol%. This ratio represents the total molar number (M) of all long-chain hydrocarbon functional groups present in the conductive polymer. L ), or the number of moles of monomeric units with long-chain hydrocarbon functional groups (M L ), or the number of moles of monomers having all long-chain hydrocarbon functional groups used to prepare thiophene polymers (M L The ratio of the number of moles (M) of all monomer units present in the conductive polymer, or the number of moles (M) of all monomers used to prepare the conductive polymer. This ratio may be greater than or equal to any lower limit chosen from the lower limits listed above; or it may be greater than or equal to any lower limit chosen from the lower limits listed above, while being less than or equal to any upper limit chosen from the upper limits listed above.

[0083] Conductive polymers may contain a first hydrocarbon functional group and a second hydrocarbon functional group.

[0084] The first hydrocarbon functional group is a long-chain hydrocarbon functional group with a relatively large number of carbon atoms. The lower limit for the number of carbon atoms in the first hydrocarbon functional group can be around 10, 11, or 12, and the upper limit can be around 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10. The number of carbon atoms in the first hydrocarbon functional group can be greater than or equal to any lower limit chosen from the list above; or it can be greater than or equal to any lower limit chosen from the list above, while being less than or equal to any upper limit chosen from the list above.

[0085] The second hydrocarbon functional group is a functional group with a relatively small number of carbon atoms in a long-chain hydrocarbon. The lower limit for the number of carbon atoms in the second hydrocarbon functional group can be approximately 3, 4, 5, 6, 7, or 8, and the upper limit can be approximately 9, 8, 7, or 6. The number of carbon atoms in the second hydrocarbon functional group can be greater than or equal to any lower limit chosen from the list above; or it can be greater than or equal to any lower limit chosen from the list above, while being less than or equal to any upper limit chosen from the list above.

[0086] The number of carbon atoms in each of the first and second hydrocarbon functional groups can be the number of carbon atoms in a straight-chain hydrocarbon chain present in the hydrocarbon functional group. For example, the first and second hydrocarbon functional groups can each independently be one or more selected from alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, and alkylcarbonyloxy, and in a suitable example, can be alkyl and / or alkoxy, wherein the number of carbon atoms can be the number of carbon atoms in the alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, and alkylcarbonyloxy groups.

[0087] Alkyl, alkenyl, alkynyl, alkoxy, alkyl carbonyl, and alkyl carbonyloxy can have straight-chain or branched structures. In the case of a straight chain, the total number of carbons can be within the range described above. In the case of a branched chain, the number of carbons constituting the longest straight chain in the branched structure can be within the range described above.

[0088] As mentioned above, the carbon number of a long-chain hydrocarbon functional group is the functional group that exhibits enhanced vibrational energy at increasing temperatures, where a higher carbon number at the same temperature corresponds to a higher vibrational energy. That is, at the same temperature, the first hydrocarbon functional group exhibits higher vibrational energy than the second hydrocarbon functional group, and the sum of the vibrational energies of these two functional groups can optimize the properties of conductive polymers that are difficult to precisely control with a single functional group.

[0089] For example, the first hydrocarbon functional group exhibits enhanced vibrational energy at elevated temperatures, while the second hydrocarbon functional group dilutes the vibrational energy of the first hydrocarbon functional group at the same temperature. Thus, the dedoping start temperature (starting point) of the conductive polymer can be precisely controlled according to the desired purpose.

[0090] The ratio of the total number of moles of the first and second hydrocarbon functional groups, or the total number of moles of monomer units having the first hydrocarbon functional group and monomer units having the second hydrocarbon functional group, to the total number of moles of monomer units (M) of the conductive polymer can be 100 × M as described above. L Adjust within the same range as / M.

[0091] The lower limit of the ratio (M2 / M1) of the molar number of the second hydrocarbon functional group (M2) or the molar number of monomer units having the second hydrocarbon functional group (M2) to the molar number of the first hydrocarbon functional group (M1) or the molar number of monomer units having the first hydrocarbon functional group (M1) can be approximately 0.01, 0.05, 0.1, or 0.5, and the upper limit can be approximately 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0.7. This ratio can be greater than or equal to any lower limit chosen from the lower limits listed above, while being less than or equal to any upper limit chosen from the upper limits listed above. The ratio M2 / M1 can be varied by considering the desired level of vibrational energy and the design values ​​of the polymer layers.

[0092] Conductive polymers can contain polar functional groups along with long-chain hydrocarbon functional groups. Monomers with polar functional groups can be thiophene monomers.

[0093] The term polar functional group is a functional group that contains one or more polar atoms, such as oxygen and / or nitrogen. Examples of such functional groups include, but are not limited to, carboxyl, hydroxyl, amino, cyano, nitro, ether, alkoxy and / or functional groups of Formula 1 below.

[0094] In one example, the alkoxy group can be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy group can be straight-chain, branched, or cyclic, and suitably can be straight-chain or branched. The alkoxy group can optionally be substituted by one or more substituents.

[0095] In one instance, a polar functional group can be a functional group of Equation 1 below.

[0096] [Formula 1] In Formula 1, L1 is a single bond, alkylene, or alkylidene, L2 is an alkylene or alkylidene, R1 is hydrogen or alkyl, and m is any number.

[0097] In Equation 1, L1 is a single bond, which means that L1 does not exist and the oxygen atom between L1 and L2 is directly connected to the monomer.

[0098] In one example, the alkyl group R1 in Formula 1 may be an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or may be methyl or ethyl. The alkyl group may be straight-chain, branched, or cyclic, and suitably may be straight-chain or branched. The alkyl group may optionally be substituted with one or more substituents.

[0099] The term alkylene refers to a divalent functional group formed by removing one hydrogen atom from each of two different carbon atoms in an alkane, while the term alkylidene refers to a divalent functional group formed by removing two hydrogen atoms from one carbon atom in an alkane.

[0100] In one example, the alkylene groups L1 and L2 in Formula 1 may each be alkylene groups having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, or may each be ethylene or propylene. The alkylene groups may be straight-chain, branched, or cyclic, and suitably may be straight-chain or branched. The alkylene groups may optionally be substituted with one or more substituents.

[0101] In one example, the alkylidene groups of L1 and L2 in Formula 1 may each be 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, or may each be a methylene, ethoxy, or propylidene group. The alkylidene group may be straight-chain, branched, or cyclic, and suitably may be straight-chain or branched. The alkylidene group may optionally be substituted by one or more substituents.

[0102] In Equation 1, the lower limit of m can be 1, 2, 3, or 4, and its upper limit can be approximately 10, 9, 8, 7, 6, 5, 4, or 3. The aforementioned n can be greater than or equal to any lower limit chosen from the listed lower limits, while being less than or equal to any upper limit chosen from the listed upper limits.

[0103] Polar functional groups can bond polymer layers to each other with appropriate binding forces and can also bind to long-chain hydrocarbon functional groups, significantly improving the dispersibility of the conductive materials described below in the polymer layers. Furthermore, polar functional groups can also play a role in suppressing the PTC effect at relatively low temperatures.

[0104] The molar number of polar functional groups and long-chain hydrocarbon functional groups in conductive polymers can be controlled to ensure appropriate effects.

[0105] For example, the number of moles of long-chain hydrocarbon functional groups (M) in conductive polymersL ) or the number of moles of monomeric units with long-chain hydrocarbon functional groups (M L ), and the number of moles of polar functional groups (M) P ) or the number of moles of monomeric units with polar functional groups (M) P The ratio of (M) L / M P The lower limit can be approximately 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, or 9. The upper limit can be approximately 500, 450, 400, 350, 300, 250, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, or 9.5. The ratio M L / M P It can be within a range that is less than or equal to, or less than, any upper limit chosen from the upper limits listed above; or within a range that is greater than or equal to, or greater than, any lower limit chosen from the lower limits listed above; or within a range that is greater than or equal to, or greater than, any lower limit chosen from the lower limits listed above, while being less than or equal to, or less than, any upper limit chosen from the upper limits listed above. Here, when the ratio M... L / M P When the ratio is between monomer units, the relevant ratio can be the molar number M of monomer units with all long-chain hydrocarbon functional groups present in the conductive polymer. L The number of moles M of monomer units having all polar functional groups P The ratio; or the molar number M of monomers with all long-chain hydrocarbon functional groups used to prepare conductive polymers. L The molar number M of monomers having all polar functional groups P The ratio of .

[0106] The total number of moles M of monomer units with long-chain hydrocarbon functional groups and monomer units with polar functional groups. S The ratio of the molar number M of all monomer units in the conductive polymer can be 100×M as described above. T Adjust within the same range as / M. In this case, the number of moles M T Replace with the number of moles M S .

[0107] For example, conductive polymers may contain units of Formula 2 below as thiophene monomer units.

[0108] [Equation 2] In Equation 2, R2 and R3 can each be independently hydrogen, a polar functional group, or a long-chain hydrocarbon functional group. In another example, R2 and R3 in Equation 2 can also be connected to each other to form a divalent functional group in Equation 3.

[0109] [Formula 3] In Formula 3, L3 and L4 can each be a single bond, an alkylene group, or an alkylidene group, and R4 and R5 can each be a hydrogen group, a polar functional group, or a long-chain hydrocarbon functional group.

[0110] In Equation 2, when R2 and R3 are each independently hydrogen, a polar functional group or a long-chain hydrocarbon functional group, at least one of R2 and R3 can be a polar functional group or a long-chain hydrocarbon functional group.

[0111] In Equation 2, when R2 and R3 form a divalent functional group of Equation 3, at least one of R4 and R5 can be a polar functional group or a long-chain hydrocarbon functional group.

[0112] In Formula 3, the meanings and specific examples of single bonds, alkylene groups, and alkylidenes are the same as in Formula 1. The technical significance and specific examples of long-chain hydrocarbon functional groups and polar functional groups in Formulas 2 and 3 are as described above.

[0113] The number of moles M of the unit in Equation 2 C2 The ratio of the total number of monomer units M in the conductive polymer to the total number of monomer units M can be adjusted to a ratio of 100×M. T / M is the same, where M T Replace with M C2 .

[0114] In one instance, the conductive polymer may comprise a monomer unit represented by Formula 4 below. The monomer unit of Formula 4 may be an example of a monomer unit having a first hydrocarbon functional group.

[0115] [Formula 4] In Equation 4, R6 and R7 can each be hydrogen or a first hydrocarbon functional group independently. In this case, one or more of R6 and R7 mentioned above can be a first hydrocarbon functional group.

[0116] In another instance, R6 and R7 can be connected to each other to form a divalent functional group of Formula 5.

[0117] [Formula 5] In Formula 5, L5 and L6 are each independently a single bond, alkylene group, or alkylidene group, and R8 and R9 are each independently a hydrogen group or a first hydrocarbon functional group, but at least one of R8 and R9 can be a first hydrocarbon functional group.

[0118] The specific details of the first hydrocarbon functional group are as described above, and the specific details of the single bond, alkylene group, or alkylidene group are as described in Formula 1 above.

[0119] The conductive polymer may also contain monomer units represented by Formula 6 below. The monomer unit of Formula 6 above may be an example of a monomer unit having a second hydrocarbon functional group.

[0120] [Formula 6] In Equation 6, R 10 and R 11 Each can be an independent hydrogen or second hydrocarbon functional group; in this case, the above R... 10 and R 11 One or more of them can be second hydrocarbon functional groups.

[0121] In another instance, the aforementioned R 10 and R 11 They can connect with each other to form divalent functional groups as shown in Equation 7 below.

[0122] [Formula 7] In Formula 7, L7 and L8 are each independently a single bond, an alkylene group, or an alkylidene group, and R 12 and R 13 Each is independently a hydrogen or second hydrocarbon functional group, but R 12 and R 13 At least one of them is a second hydrocarbon functional group.

[0123] The specific details of the second hydrocarbon functional group are as described above, and the specific details of the single bond, alkylene group, or alkylidene group are as described in Formula 1 above.

[0124] The conductive polymer may also contain monomer units represented by Formula 8 below. The monomer unit of Formula 8 above may be an example of a monomer unit having polar functional groups.

[0125] [Formula 8] In Equation 8, R 14 and R 15 Each can be either hydrogen or a polar functional group independently. In the above case, R 14 and R 15 One or more of them are polar functional groups.

[0126] In another example, R in Equation 8 above 14 and R 15 They can connect with each other to form divalent functional groups as shown in Equation 9 below.

[0127] [Formula 9] In Equation 9, L9 and L 10 Each is independently a single bond, alkylene group, or alkylidene group, R 16 and R 17 Each is independently either hydrogen or a polar functional group, but R 16 and R 17 At least one of them is a polar functional group.

[0128] The specific details of the polar functional groups are as described above, and the specific details of the single bonds, alkylene groups, or alkylidenes are as described in Formula 1 above.

[0129] When the conductive polymer simultaneously contains monomer units of Formula 4 and Formula 6, the total molar number M of the monomer units of Formula 4 and Formula 6 is... 4+6 The ratio of the total number of monomer units M contained in the conductive polymer to the ratio of 100×M as described above can be used. L Adjust within the same range as / M, where M L Replace with M 4+6 .

[0130] The ratio of the number of moles M4 of the monomer unit in Equation 4 to the number of moles M6 of the monomer unit in Equation 6 can be adjusted within the same range as the ratio M2 / M1. In this case, the number of moles M1 can be the number of moles of the monomer unit in Equation 4, and the number of moles M2 can be the number of moles of the monomer unit in Equation 6.

[0131] When the conductive polymer contains the monomer unit of Formula 8 above, it may contain the unit to satisfy the molar ratio M L / M P In this case, the number of moles of the monomer unit in Equation 8 above becomes the mole number M. P In addition, the number of moles M L It can be the number of moles of the single unit in Formula 4 above, the number of moles of the single unit in Formula 6 above, or the total number of moles of the single unit in Formula 4 above and the single unit in Formula 6 above.

[0132] When the conductive polymer contains monomer units of formulas 4, 6, and 8, the total number of moles M of the monomer units of formulas 4, 6, and 8 is... 4+6+8 The ratio of the total number of monomer units M in the conductive polymer to the total number of moles can be expressed as a ratio of 100×M. T Adjust within the same range as / M. In this case, the number of moles M 4+6+8 Becoming the number of moles M T .

[0133] The conductive polymer comprises the aforementioned monomer units, and may further comprise other monomer units. For example, in addition to thiophene monomer units, the conductive polymer may also comprise non-thiophene monomer units.

[0134] Non-thiophene monomer units are units of monomers other than thiophene monomers, and are used to adjust the oxidation potential of conductive polymers. For example, a non-thiophene monomer unit can be a unit of a monomer that can copolymerize with a thiophene monomer, and when manufactured as a homopolymer, it exhibits a lower oxidation potential than polythiophene.

[0135] In the above case, the molar ratio of thiophene monomer units in the conductive polymer can be approximately equal to a ratio of 100×M. T The ratio of non-thiophene monomer units can be adjusted within the same range as / M. Furthermore, the desired oxidation potential can be considered to adjust the proportion of these units.

[0136] For example, in conductive polymers, the lower limit for the number of moles of non-thiophene monomer units per mole of thiophene monomer unit can be approximately 0.05 mol, 0.1 mol, 0.15 mol, 0.2 mol, 0.22 mol, or 0.24 mol, and the upper limit can be approximately 1 mol, 0.9 mol, 0.8 mol, 0.7 mol, 0.6 mol, 0.5 mol, 0.4 mol, or 0.3 mol. This ratio can be less than or equal to or less than any upper limit chosen from the listed upper limits; or greater than or equal to or greater than any lower limit chosen from the listed lower limits; or greater than or equal to or greater than any lower limit chosen from the listed lower limits while being less than or equal to or less than any upper limit chosen from the listed upper limits.

[0137] The non-thiophene monomer unit can be, for example, an aromatic monomer unit or a nitrogen-containing heterocyclic monomer unit. An aromatic monomer unit is a unit formed from aromatic monomer units, and a nitrogen-containing heterocyclic monomer unit is a unit formed from nitrogen-containing heterocyclic monomers.

[0138] For example, a non-thiophene monomer unit can be a monomer unit of Formula 10 below.

[0139] [Formula 10] In Equation 10, R 18 R 19 and R 20 Each can be an independent hydrogen, polar functional group, or hydrocarbon functional group.

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

[0141] Alkyl groups can each independently be alkyl groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

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

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

[0144] Alkyl and alkenyl groups can each be independently straight-chain, branched, or cyclic. Alkyl, alkenyl, and aryl groups can each be independently and optionally substituted by one or more substituents.

[0145] The specific details of the polar functional groups are as described above. For example, the unit in Formula 10 above can be a polypyrrole unit.

[0146] In another example, the nonthiophene monomer unit can be a unit of Equation 11 below.

[0147] [Equation 11] In Equation 11, L 11 It can be a single bond, alkylene group, alkylidene group, O or NR. 1 Here, the meanings of single bond, alkylene group, or alkylidene group are as described in Formula 1. Furthermore, R... 1 It can be hydrogen, alkyl, alkenyl or aryl.

[0148] In Equation 11, R 21 To R 24 Each atom can be hydrogen, alkyl, alkenyl, amino, alkoxy, aryl, or halogen.

[0149] The specific types of alkyl, alkenyl, and aryl groups in Formula 11 are as described in Formula 10.

[0150] The alkoxy group in Formula 11 can be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Each alkoxy group can be independently straight-chain, branched, or cyclic. The alkoxy group can optionally be substituted with one or more substituents.

[0151] For example, the monomer unit in Formula 11 can be a polyaniline or a polyphenylene monomer unit.

[0152] In another example, the nonthiophene monomer unit can be a unit of Equation 12 below.

[0153] [Equation 12] In Equation 12, X1 can be S, O, or NR. 1 In addition, R 1 It can be hydrogen, alkyl, alkenyl or aryl.

[0154] In Equation 12, R 25 To R 28 Each can be hydrogen, alkyl, alkenyl, alkoxy, aryl, or halogen, and each can be independent of the others.

[0155] The specific types of alkyl, alkenyl, alkoxy, and aryl groups in Formula 12 are the same as those in Formulas 10 and 11. The monomer unit of Formula 12 can be a polyindole unit.

[0156] In another example, the nonthiophene monomer unit can be a unit of Equation 13 below.

[0157] [Equation 13] In Equation 13, R 29 To R 34 Each of these can be hydrogen, alkyl, alkenyl, alkoxy, aryl, hydroxyl, or halogen. The specific types of alkyl, alkenyl, alkoxy, and aryl in Formula 13 are the same as those in Formulas 10 and 11.

[0158] The monomer unit in Equation 13 above can be a polyazine unit.

[0159] In another example, the nonthiophene monomer unit can be a unit of Equation 14 below.

[0160] [Formula 14] In Equation 14, X2 can be a carbon atom (CR). a R b ) or nitrogen atom (NR 1 ). Here, R a R b and R 1 Each can be hydrogen, alkyl, alkenyl, or aryl independently.

[0161] Meanwhile, the unit of Formula 14 above can be unsubstituted or substituted by one or more of the following: alkyl, alkenyl, alkoxy, aryl and halogen.

[0162] The specific types of alkyl, alkenyl, alkoxy, and aryl groups in Formula 14 are the same as those in Formulas 10 and 11.

[0163] For example, the monomer unit in Formula 14 above can be a polyfluorene or polycarbazole unit.

[0164] In another example, the nonthiophene monomer unit can be a unit of Equation 15 below.

[0165] [Formula 15] The unit of Formula 15 may be unsubstituted or substituted with one or more of the following: alkyl, alkenyl, alkoxy, aryl and halogen.

[0166] The specific types of alkyl, alkenyl, alkoxy, and aryl groups in Formula 15 are the same as those in Formulas 10 and 11. For example, the monomer unit in Formula 15 may be a polypyrene unit.

[0167] The weight-average molecular weight of the conductive polymer can be within a predetermined range. The lower limit of the weight-average molecular weight of the conductive polymer can be approximately 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, or 95,000, and the upper limit can be approximately 1,000,000. The weight-average molecular weight can be approximately 950,000, 900,000, 850,000, 800,000, 750,000, 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000, 350,000, 300,000, 250,000, 200,000, 150,000, 130,000, 110,000, or 100,000. The weight-average molecular weight can be less than or equal to any upper limit chosen from the listed upper limits, and greater than or equal to any lower limit chosen from the listed lower limits. The unit of weight-average molecular weight is g / mol, which can be confirmed according to the description in "2. GPC (Gel Permeation Chromatography)" in the Examples section of this specification.

[0168] The molecular weight distribution of the conductive polymer, i.e., the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn), can be within a predetermined range. The lower limit of the molecular weight distribution can be approximately 2, 2.5, 3, or 3.5, and the upper limit can be approximately 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, or 3.7. The molecular weight distribution can be less than or equal to any upper limit chosen from the above-listed upper limits, while being greater than or equal to or greater than any lower limit chosen from the above-listed lower limits. The molecular weight distribution can be confirmed according to the description in "2. GPC (Gel Permeation Chromatography)" in the Examples section of this specification.

[0169] If the conductive polymer contains the above-described units in the above proportions, it may further contain other monomer units.

[0170] The polymer layer contains a conductive polymer, and therefore can exhibit the properties described above. If the polymer layer contains a conductive polymer, it can further contain any additional components.

[0171] For example, the polymer layer may further contain a conductive material along with the conductive polymer. By adding this material, the oxidation potential of the polymer layer can be further tuned. As the conductive material, a material with appropriate conductivity can be used; for example, one or more materials selected from carbon particles, carbon fibers, graphene, graphite, carbon black, and carbon nanotubes can be used as the conductive material.

[0172] As a conductive material, an appropriate type can be selected and used from the above types. The shape of the material can be granular (spherical, irregular or other shapes), plate or fiber, etc., but is not limited to these.

[0173] The size of the conductive material can also be adjusted as needed. For example, the lower limit of the size of conductive materials can be around 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, while the upper limit can be around 100000 nm, 90000 nm, 80000 nm, 70000 nm, 60000 nm, 50000 nm, 40000 nm, 30000 nm, 20000 nm, 10000 nm, 5000 nm, 1000 nm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, etc. The sizes are approximately 600 nm, 550 nm, 500 nm, 450 nm, 400 nm, 350 nm, 300 nm, 250 nm, 200 nm, 200 nm, 150 nm, 100 nm, 90 nm, 80 nm, or 70 nm. The size can be less than or equal to any upper limit chosen from the listed upper limits; or greater than or equal to any lower limit chosen from the listed lower limits; or greater than or equal to any lower limit chosen from the listed lower limits while being less than or equal to any upper limit chosen from the listed upper limits. The above sizes are the average diameter (so-called D50 particle size) measured according to the contents of section "12. Average Particle Size" described in the Embodiments section of this specification.

[0174] Depending on the requirements and considering factors such as dispersibility, the conductive material may undergo surface treatment.

[0175] In this case, a surface treatment agent with suitable compatibility with the conductive polymer can be used as the surface treatment agent. For example, conductive materials can be surface-treated using polyphenolic compounds as surface treatment agents. Polyphenolic compounds refer to compounds that include a structure containing two or more hydroxyl groups, said hydroxyl groups being substituted in and linked to benzene. Such compounds can be exemplified as so-called catechol compounds (i.e., catechol, or compounds including related structures), examples of which include, but are not limited to, dopamine, polydopamine, 3,4-dihydroxyphenylalanine, norepinephrine, tannic acid, humic acid, and / or lignin.

[0176] There are no restrictions on the methods for surface treatment of conductive materials using surface treatment agents. For example, methods such as mixing conductive materials and surface treatment agents in a suitable solvent can be used, or methods such as synthesizing or polymerizing surface treatment agents on the surface of conductive materials can be applied.

[0177] The desired oxidation potential can be considered to adjust the content of the conductive material. Generally, as the content of the conductive material in the polymer layer increases, the oxidation potential of the polymer layer decreases. Therefore, the oxidation potential of the electrode active material, and correspondingly, the required oxidation potential of the polymer layer, can be considered to adjust the content of the conductive material. For example, relative to 100 parts by weight of the conductive polymer, the lower limit of the content of the conductive material in the polymer layer can be approximately 0.5 parts by weight, 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 90 parts by weight, or 100 parts by weight, while the upper limit can be approximately 1,000 parts by weight, 900 parts by weight, 800 parts by weight, 700 parts by weight, 600 parts by weight, 50 parts by weight, etc. Approximately 0 parts by weight, 400 parts by weight, 300 parts by weight, 200 parts by weight, 150 parts by weight, 100 parts by weight, 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 less than or equal to or less than any upper limit chosen from the listed upper limits; or greater than or equal to or greater than any lower limit chosen from the listed lower limits; or greater than or equal to or greater than any lower limit chosen from the listed lower limits, while being less than or equal to or less than any upper limit chosen from the listed upper limits.

[0178] At this ratio, the conductive material interacts appropriately with the conductive polymer, thereby effectively forming a polymer layer of the desired shape.

[0179] The electrode may include an active material layer formed on a polymer layer. A typically applied layer may also serve as the active material layer.

[0180] Typically, the active material layer contains the electrode active material. There are no particular restrictions on the specific type of electrode active material; materials that form either the positive or negative electrode can generally be used.

[0181] For example, when the active material layer is a positive electrode active material layer, the electrode active material may include: layered compounds such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or compounds substituted by one or more transition metals; lithium iron oxide such as LiFe3O4; lithium manganese oxide such as the formula Li 1+c1 Mn 2-c1 O4 (0 ≤ c1 ≤ 0.33), LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxide such as LiV3O8, V2O5 or Cu2V2O7; lithium nickel oxide of Ni-site type represented by the formula LiNi 1-c2 M c2 O2 (where M is at least one selected from Co, Mn, Al, Cu, Fe, Mg, B and Ga, and 0.01 ≤ c2 ≤ 0.3); lithium manganese composite oxide represented by the formula LiMn 2-c3 M c3 O2 (where M is at least one selected from Co, Ni, Fe, Cr, Zn and Ta, and 0.01 ≤ c3 ≤ 0.1) or Li2Mn3MO8 (where M is at least one selected from Fe, Co, Ni, Cu and Zn); lithium nickel cobalt manganese (NCM) composite oxide, lithium nickel cobalt manganese aluminum (NCMA) composite oxide, and LiMn2O4 in which a part of Li in the formula is substituted by alkaline earth metal ions, etc., but not limited thereto.

[0182] When the active material layer is a negative electrode active material layer, as the electrode active material, for example, a compound capable of reversibly inserting and extracting lithium can be used. A specific example may include: carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber and amorphous carbon; metal 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; metal oxides capable of doping and dedoping lithium such as SiO a (0 < a < 2), SnO2, vanadium oxide and lithium vanadium oxide; or composite materials containing metal compounds and carbonaceous materials such as Si-C composite material or Sn-C composite material, etc., and any one or a mixture of two or more of the above can be used.

[0183] A thin film of metallic lithium can also be used as the negative electrode active material, and as the carbon material, low-crystalline carbon and high-crystalline carbon, etc. can also be used. As the low-crystalline carbon, representative ones are soft carbon and hard carbon, and as the high-crystalline carbon, representative ones are high-temperature calcined carbon such as amorphous, plate-shaped, flaky, spherical or fibrous natural graphite or artificial graphite, kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, mesophase carbon microbead, mesophase pitch, and coke derived from petroleum and coal tar pitch.

[0184] The content of electrode active material in the active material layer can be in the range of about 80% to 99.5% by weight, or in the range of 88% to 99% by weight, relative to the total weight of the active material layer, but this ratio can vary depending on the application or design of the electrode.

[0185] The active material layer may further include an adhesive. The adhesive is used to improve the adhesion between active materials and the adhesion between the active material layer and the current collector. There are no particular limitations on examples of adhesives, and one or more selected from the following can be used, such as PVDF (polyvinylidene fluoride), PVA (polyvinyl alcohol), SBR (styrene-butadiene rubber), PEO (polyethylene oxide), CMC (carboxymethyl cellulose), cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate polymer (polyethylene-co-vinyl acetate), and polyarylates.

[0186] In one instance, the amount of binder in the active material layer may be in the range of 0.1 to 10 parts by weight or 0.5 to 5 parts by weight relative to 100 parts by weight of electrode active material, but is not limited thereto.

[0187] As needed, the active material layer may further include a conductive material. There are no particular restrictions on the use of any known material, provided that the conductive material is conductive and does not cause chemical changes in the secondary battery. For example, graphite, such as natural or artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black; conductive fibers, such as carbon fibers or metal fibers; conductive tubes, such as carbon nanotubes (CNTs); metal powders, such as fluorocarbons, aluminum or nickel powder; conductive whiskers, such as zinc oxide or potassium titanate; conductive metal oxides, such as titanium oxide; conductive materials such as polystyrene derivatives, etc.

[0188] In one example, the content of conductive material in the active material layer may be from 0.1 parts by weight to 20 parts by weight, or from 0.3 parts by weight to 10 parts by weight, relative to 100 parts by weight of electrode active material, but is not limited thereto.

[0189] In addition to the components mentioned above, the active material layer may optionally include any necessary known components.

[0190] As mentioned above, in order for the polymer layer to exhibit the desired effect, the selection of long-chain hydrocarbon functional groups and / or conductive materials is important. In addition, the control of the arrangement of long-chain hydrocarbon functional groups and / or the dispersion of conductive materials is also important. The desired arrangement and / or dispersion can be ensured by the manufacturing methods described below.

[0191] The manufacturing method may include the step of forming a polymer layer using a polymer solution containing a conductive polymer and a conductive material (if desired).

[0192] In the steps described above, the conductive polymer used is as described above, and the coating solution can be prepared by dissolving the polymer in a suitable solvent. At this point, there are no particular restrictions on the type of solvent if it can dissolve at least a portion of the conductive polymer.

[0193] In the above steps, the lower limit of the concentration of the conductive polymer present in the polymer solution can be approximately 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%, and the upper limit can be approximately 20 wt%, 18 wt%, 16 wt%, 14 wt%, 12 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, or 3%. This ratio can be greater than or equal to any lower limit chosen from the lower limits listed above; or less than or equal to any upper limit chosen from the upper limits listed above; or greater than or equal to any lower limit chosen from the lower limits listed above, while being less than or equal to any upper limit chosen from the upper limits listed above. The concentration can be changed as needed.

[0194] Conductive polymers can be formed by known polymerization methods. For example, methods known for preparing polythiophene include oxidative polymerization or free radical reactions.

[0195] A polymer layer is formed on a current collector using a polymer solution. This method typically includes the steps of coating the current collector with the polymer solution and heat-treating the coated solution. In this specification, the polymer layer formed on the current collector prior to heat treatment may be referred to as the precursor. The crystallinity of the conductive polymer and the orientation of the long-chain hydrocarbon functional groups can be controlled by the conditions of the heat treatment.

[0196] For example, the heat treatment step can be performed in two steps. For example, the heat treatment step may include: a first step of performing a first heat treatment on the precursor at a temperature range T1; and a second step of performing a second heat treatment on the precursor at a temperature range T2 after the first step.

[0197] The conditions of the first and second steps can be adjusted to achieve the desired orientation or arrangement of the conductive polymer and the dispersion state of the conductive material.

[0198] For example, the temperature range T1 of the first heat treatment can be adjusted within a predetermined range. For example, the lower limit of the temperature range T1 can be approximately 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃ or 140℃, and its upper limit can be approximately 300℃, 290℃, 280℃, 270℃, 260℃, 250℃, 240℃, 230℃, 220℃, 210℃, 200℃, 190℃, 180℃, 170℃, 160℃, 150℃ or 140℃. The temperature range T1 can be greater than or equal to any lower limit chosen from the lower limits listed above; or it can be less than or equal to any upper limit chosen from the upper limits listed above, while being greater than or equal to any lower limit chosen from the lower limits listed above.

[0199] In the heat treatment step, the temperature range T1 of the first heat treatment and the temperature range T2 of the second heat treatment can be adjusted. For example, the lower limit of the ratio of temperature ranges T1 and T2 can be approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, or 1.2, and the upper limit can be approximately 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, or 1.1. This ratio can be greater than or equal to or greater than any lower limit chosen from the lower limits listed above; or less than or equal to or less than any upper limit chosen from the upper limits listed above; or less than or equal to or less than any upper limit chosen from the upper limits listed above, while being greater than or equal to or greater than any lower limit chosen from the lower limits listed above.

[0200] In one example, during the heat treatment step, the temperature range T1 of the first heat treatment can be adjusted to be higher than the temperature range T2 of the second heat treatment.

[0201] The ratio of the heat treatment time M1 in the first heat treatment to the heat treatment time M2 in the second heat treatment can be adjusted. For example, the lower limit of the ratio M2 / M1 can be around 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, and the upper limit can be around 1,000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 290, 280, 270, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30 or 20. The ratio M2 / M1 can be greater than or equal to any lower limit chosen from the list of lower limits; or less than or equal to any upper limit chosen from the list of upper limits; or less than or equal to any upper limit chosen from the list of upper limits, while being greater than or equal to any lower limit chosen from the list of lower limits.

[0202] Here, the lower limit of the second heat treatment time M2 can be approximately 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours, 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, or 18 hours, and its upper limit can be approximately 50 hours, 48 ​​hours, 46 hours, 44 hours, 42 hours, 40 hours, 38 hours, 36 hours, 34 hours, 32 hours, 30 hours, 28 hours, 26 hours, 24 hours, 22 hours, 20 hours, 18 hours, 15 hours, 10 hours, 9 hours, 8 hours, 7 hours, 6 hours, 5 hours, 4 hours, 3 hours, 2 hours, or 1.5 hours. The second heat treatment time M2 can be greater than or equal to any lower limit chosen from the lower limits listed above; or less than or equal to any upper limit chosen from the upper limits listed above; or less than or equal to any upper limit chosen from the upper limits listed above, while being greater than or equal to any lower limit chosen from the lower limits listed above.

[0203] By appropriately adjusting the arrangement of hydrocarbon functional groups in the conductive polymer through the above heat treatment, the desired effect can be obtained.

[0204] There are no particular restrictions on the method of applying the coating solution; any known coating method can be used.

[0205] These processes produce the desired polymer layer and the current collector comprising it. Appropriate post-processing may be included as needed.

[0206] The manufacturing method may include the step of forming an active material layer on a polymer layer on a current collector. There are no particular limitations 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 electrode active materials, binders, and conductive materials onto the current collector (on the polymer layer), drying it, and then rolling it; this known method can be applied in the same manner.

[0207] This specification also discloses an electrode assembly or electrochemical element, such as a secondary battery, which includes the electrode.

[0208] Electrochemical elements may include the electrodes as positive and / or negative electrodes. If the electrodes are used as negative and / or positive electrodes, there are no particular limitations on other construction or manufacturing methods of the electrochemical elements, and known methods can be applied.

[0209] Beneficial effects This specification discloses an electrode and its application. The electrode comprises a polymer layer that exhibits a so-called PTC (Positive Temperature Coefficient) effect at a desired level and for a desired time, thus making it suitable for applications where stability issues arise due to abnormally high heat or flame. The polymer layer can exhibit oxidation potential characteristics suitable for the electrode application, and can stably maintain these oxidation potential characteristics even in harsh environments. In the polymer layer of the electrode, the PTC effect can rapidly appear at the desired time. This specification also discloses an application of the electrode. Attached Figure Description

[0210] Figure 1 This is a cross-sectional view of an exemplary electrode.

[0211] Figure 2 The results are NMR analysis of the monomer from Preparation Example 1. Detailed Implementation

[0212] The electrodes and the like are described in detail below through examples and comparative examples, but the electrodes and the like are not limited to the examples below.

[0213] 1. NMR analysis The NMR spectrometer was used at room temperature and included a Bruker UltraShield spectrometer (300 MHz) with a 5 mm triple resonance probe. 1 H-NMR analysis. The sample was diluted in a solvent (CDCl3) used for NMR measurements to a concentration of approximately 10 mg / mL and used. Chemical shifts are expressed in ppm.

[0214] 2. GPC (Gel Permeation Chromatography) The molecular weight characteristics were measured using GPC (gel permeation chromatography). The sample was placed in a 5 mL vial and diluted with chloroform to a concentration of approximately 1 mg / mL. The standard sample for calibration and the sample to be analyzed were filtered through a syringe filter (pore size: 0.45 μm), and then the molecular weight characteristics were measured. As the analysis program, Empower 3 from Waters was used. By comparing the elution time of the sample with the calibration curve, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were obtained respectively, and the molecular weight distribution (PDI) was calculated by the ratio (Mw / Mn).

[0215] The measurement conditions of GPC are as follows.

[0216] <GPC Measurement Conditions> Apparatus: Waters’ 2414 Columns: Use 3 Styragel columns from Waters 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) 3. Thickness measurement The electrode was cross-sectioned using an ion milling device (Hitachi, IM5000), and then the thickness of the polymer layer etc. was measured by taking images with a SEM (scanning electron microscope) (JEOL, JSM-7200F). The conditions for forming the cross-section by ion milling were: the device was set to the cross-section milling mode, the speed (reciprocating motion / minute) 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.

[0217] 4. Measurement of oxidation potential (polymer layer) Oxidation potential was measured as follows. A polymer layer of approximately 10 μm thickness was formed on an aluminum foil (Al foil) with a thickness of approximately 15 μm using a conductive copolymer. The polymer layer was formed in the same manner as described in the various examples or comparative examples, and was formed to a thickness of approximately 10 μm. A separator and a lithium film were laminated on the polymer layer to manufacture a laminate containing an aluminum foil / polymer layer / separator / lithium film, and the laminate was stamped into a circle with a diameter of approximately 1.4 cm. A coin cell was manufactured using the circular stamped laminate and an electrolyte (using a Welcos CR2032 coin cell kit). As the separator, the WL20C model from W Scope, Korea, was used; as the lithium film, a lithium film with a thickness of approximately 100 μm was used; as the electrolyte, an Enchem product (1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethyl methyl carbonate) was used.

[0218] The oxidation potential of the button cell was measured at 25°C using an electrochemimeter (potentiostat) (ParaSTAT-MC, Princeton Applied Research Corporation). The oxidation potential was measured by cyclic voltammetry (CV) over a range of 1.5 V to 5.5 V at scan rates of 0.17 mV / s to 0.5 mV / s.

[0219] 5. Measurement of oxidation potential (electrode active materials) Regarding the oxidation potential of the electrode active material, a button cell was manufactured using an electrode made from the electrode active material, and the relevant button cell was measured.

[0220] A slurry was prepared by mixing the electrode active material, conductive material (ECP (Kejtien Black) 0.5%, SFG (Trimrex graphite) 0.4%, DB (Denka carbon black) 0.4%), PVDF (polyvinylidene fluoride), and NMP (N-methyl-2-pyrrolidone) in a weight ratio of 75:1:1:23 (electrode active material: conductive material: PVDF: NMP). The slurry was coated onto a current collector using a doctor blade, dried at room temperature (approximately 25°C), and then held in a drying oven at 130°C for approximately 30 minutes before rolling to form an electrode active material layer with a thickness of approximately 53 μm, thus fabricating the electrode. Rolling was performed to achieve a porosity of approximately 25% for the active material layer. The porosity of the active material layer was calculated by comparing the difference between the actual density and the density after rolling; this method of obtaining porosity is known. An aluminum foil with a thickness of approximately 15 μm was used as the current collector.

[0221] A separator and lithium film are laminated onto the electrode active material layer of the electrode to create a laminate containing the electrode / separator / lithium film. This laminate is then stamped into a circle with a diameter of approximately 1.4 cm. A coin cell is manufactured using the circular stamped laminate and an electrolyte (using a Welcos CR2032 coin cell kit).

[0222] As the separator, the WL20C model from W Scope in South Korea was used; as the lithium membrane, a membrane with a thickness of about 100 μm was used; as the electrolyte, an Enchem product was used, a 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethyl methyl carbonate).

[0223] The oxidation potential of the button cell was measured at 25°C using an electrochemimeter (potentiostat) (Princeton Applied Research, PARASTAT-MC). The oxidation potential was measured by cyclic voltammetry (CV) in the range of 1.5V to 5.5V at scan rates of 0.17mV / s to 0.5mV / s.

[0224] Oxidation potential based on Li / Li + To measure.

[0225] Figure 2 This demonstrates the application of NCM (Li[Ni x Co (1-x) / 2 Mn (1-x) / 2 The oxidation potential of the electrode active material (O2, x = 0.8) was measured. The oxidation potential of the electrode active material is approximately 3.7 V.

[0226] 6. DC Resistance Measurement Method The DC resistance was evaluated using the same button cell used in the oxidation potential measurement. A voltage of 4.3 eV was applied to the button cell for 10 minutes at room temperature (25°C), and the DC resistance was measured using a Fluke digital multifunction tester (Fluke-87-5).

[0227] 7. AC impedance resistance The AC impedance was evaluated by EIS (electrochemical impedance spectroscopy) using the same coin cell as that used in the oxidation potential measurement. A voltage of 4.3 V was applied to the coin cell for 10 minutes at room temperature (25°C), and Nyquist plots were obtained by EIS measurement from 50,000 Hz to 0.1 Hz. The AC impedance obtained in the high-frequency region was measured. An electrochemimeter (potentiostat) (ParaSTAT-MC, Princeton Applied Research Corporation) was used as the EIS measurement device.

[0228] 8. Measurement of maximum rate of change of resistance (DC resistance) The maximum rate of change of resistance ΔR1 is determined according to Equation 2 below.

[0229] Equation 2 ΔR1 = Max{(R n+5 / R n ) / 5} In equation 2, R n R is the DC resistance at any temperature n℃ within the range of 25℃ to 135℃. n+5 It is the DC resistance at a temperature 5°C higher than the temperature n°C ((n+5)°C).

[0230] The above ΔR1 is measured in the following manner.

[0231] A button cell battery for DC resistance measurement was placed in the center of a convection oven (Jeotech, OF3-05W). The oven temperature was set to an initial temperature of 25°C and a final temperature of 135°C, increasing at a rate of 5°C per minute. The button cell battery was connected to a resistance measuring multimeter (Fluke Digital Multifunction Tester (Fluke-87-5)) outside the oven to perform resistance measurements. Subsequently, with the temperature increasing as set, the DC resistance was measured at various temperatures (measuring in 5°C increments up to 135°C from 25°C, 30°C, 35°C, and 40°C). The resistance R in Equation 1 was measured at each measurement temperature. n and R n+5 Calculate R n+5 / R n (R) 30 / R 25 R 35 / R 30 ~R 135 / R 130 Then divide them by 5.

[0232] The above (R) was obtained in a temperature range of 25°C to 135°C. n+5 / R n After dividing by 5, the maximum value among them is obtained as ΔR1. Using ΔR1, the temperature reactivity of the conductive copolymer (polymer layer) in increasing resistance at the on-set temperature can be confirmed.

[0233] The initial temperature is (R) n+5 / R n The temperature n°C at which ) / 5 shows the maximum value.

[0234] As a button cell used for DC resistance measurement, the same button cell used when measuring oxidation potential is employed.

[0235] 9. Measurement of maximum rate of change of resistance (AC impedance) The maximum rate of change of resistance ΔR2 is determined according to Equation 3 below.

[0236] Equation 3 ΔR² = Max{(R z+5 / R z ) / 5} In equation 3, R z R is the AC impedance resistance at any temperature z℃ within the range of 25℃ to 135℃. z+5 It is the AC impedance resistance at a temperature 5℃ higher than z℃ ((z+5)℃).

[0237] The above ΔR2 is measured in the following manner.

[0238] A button cell battery used for AC impedance resistance measurement was placed in the center of a convection oven (Jeotech, OF3-05W). The oven temperature was set to an initial temperature of 25°C and a final temperature of 135°C, increasing at a rate of 5°C per minute. The button cell battery was connected to an external resistance measuring device (potentiostat) (Princeton Applied Research, PARASTAT-MC) to enable resistance measurement. Subsequently, with the temperature increasing as set, the AC impedance resistance was measured at various temperatures (measuring at 5°C increments up to 135°C from 25°C, 30°C, 35°C, and 40°C). R in Equation 2 was measured at each measurement temperature. z and R z+5 Calculate R z+5 / R z (R) 30 / R 25 R 35 / R 30 ~R 135 / R 130 Then divide them by 5.

[0239] The above (R) was obtained in a temperature range of 25°C to 135°C. z+5 / R z After ) / 5, the maximum value among them is obtained as the above ΔR2.

[0240] The temperature reactivity of the conductive copolymer (polymer layer) at the initial temperature can be confirmed by the above ΔR2.

[0241] The initial temperature is (R) z+5 / Rz The temperature n°C at which ) / 5 shows the maximum value.

[0242] The same button cell used for the measurement is the same one used when measuring the oxidation potential.

[0243] The AC impedance resistance was confirmed as the resistance obtained from the semicircle in the high-frequency region of the Nyquist plot by applying a voltage of 4.3V for 10 minutes and using the EIS measurement method from 50,000Hz to 0.1Hz.

[0244] 10. Charging and discharging tests Charge and discharge tests were conducted by manufacturing button cells. Button cells were manufactured using the CR2032 standard button cell kit (Welcos CR2032 button cell kit). Electrodes manufactured in the various examples or comparative examples were used as positive electrodes, and a lithium film (thickness: approximately 100 μm) was used as the negative electrode. An Enchem product, a 1M LiPF6 solution (solvent: EC / DMC / EMC = 3 / 4 / 3 (mass ratio), EC: ethylene carbonate, DMC: dimethyl carbonate, EMC: ethyl methyl carbonate) was used as the electrolyte, and a PE (polyethylene) separator (W-Scope, Korea, model WL20C) was used as the separator.

[0245] Charge and discharge tests were conducted using button batteries, and the constant current-constant voltage (CC-CV) method was used for the tests: 0.1C / 0.1C (condition 1), 0.5C / 0.1C (condition 2), 0.5C / 0.5C (condition 3), 0.5C / 1C (condition 4), and 0.5C / 2C (condition 5) were used respectively.

[0246] 11. High-temperature discharge capacity reduction rate The button cell battery is manufactured in the same manner as in the charge / discharge test.

[0247] The button cell battery was charged and discharged once at 25°C, and the capacity at 0.2C was set as the room temperature discharge capacity (C). 25 A single charge / discharge cycle refers to charging at a rate of 0.2C using constant current (CC) / constant voltage (CV) by setting a final charging voltage of 4.5V and a final charging current of 1mA, and discharging at a rate of 0.2C using constant current (CC) by setting a final discharging voltage of 3.0V, repeating the above process once as a cycle.

[0248] Meanwhile, after keeping the button cell at 130°C for approximately 10 minutes, the high-temperature discharge capacity (C) was obtained using the following method. 130For button cells maintained at high temperatures, the following process is configured as one cycle: charging at a rate of 0.5C (constant current) / CV (constant voltage) by setting a final charging voltage of 4.5V and a final charging current of 1mA, and discharging at a rate of 2C (constant current) by setting a final discharging voltage of 3.0V. This cycle is repeated 30 times, and the discharge capacity after 30 charge / discharge cycles is taken as the high-temperature discharge capacity (C). 130 30 charge / discharge cycles were performed at 45°C.

[0249] 12. Average particle size The average particle size (D50 diameter) of conductive particles was measured using a MASTERSIZER 3000 apparatus purchased from Marvern, according to ISO-13320 standard. Toluene was used as the solvent during the measurement. If the sample (conductive particles) is dispersed in the solvent and illuminated with a laser, the laser light is scattered by the sample dispersed in the solvent. Since the intensity and directionality of the scattered laser light vary according to the particle size, the average particle size can be obtained by analysis using Mie theory. Based on this analysis, the measurement results were converted into the particle size distribution of spheres with the same volume as the dispersed sample, resulting in a volume-based cumulative particle size distribution map. The particle size at the 50% cumulative point of this map (the median particle size) was designated as the average particle size (D50 diameter).

[0250] Preparation Example 1. Synthesis of Monomer (A) The monomer of formula A is synthesized in the following manner.

[0251] [Formula A] In 150 mL of toluene, 3 g (26.28 mmol, 1 eq) of 3-methoxythiophene and 7.03 g (39.42 mmol, 1.5 eq) of triethylene glycol monomethyl ether were dissolved and mixed with 500 mg of p-toluenesulfonic acid (p-TsOH) (2.63 mmol, 0.1 eq). The mixture was refluxed at 120°C under a nitrogen atmosphere while the reaction proceeded, thereby removing methanol produced in the reaction (ether exchange) through a type 4A molecular sieve packed in an extractor (Soxhlet extractor). After reflux for 24 hours, the mixture was cooled to room temperature, quenched with water, extracted with ethyl acetate, washed with brine, and dried over magnesium sulfate (MgSO4). The solvent was removed using a rotary evaporator, and the residue was purified by column chromatography eluting with dichloromethane / hexane (2:1) to give the target compound (monomer (A)). The NMR analysis results of monomer (A) are shown in the figure. Figure 2 middle.

[0252] Preparation Example 2. Synthesis of Conductive Polymer (A) A solution containing 3.20 g (19.71 mmol, 3 eq) of ferric chloride (III) dissolved in 150 mL of dichloromethane was added to a mixture of 0.7 g (2.96 mmol, 0.6 eq) of 3-dodecylthiophene, 0.3 g (1.48 mmol, 0.3 eq) of 3-hexylthiophene, 0.12 g (0.49 mmol, 0.1 eq) of monomer (A) from Preparation Example 1, and 0.37 g (1.23 mmol, 0.3 eq) of pyrrole. The mixture was polymerized at 25°C for 24 hours to prepare conductive polymer (A). In conductive polymer (A), the molar ratio of 3-dodecylthiophene unit (I), 3-hexylthiophene unit (II), monomer (A) unit (III) from Preparation Example 1, and pyrrole (IV) unit was approximately 2.96:1.48:0.49:1.23 (I:II:III:IV). The polymerization solution was placed in a permeation membrane with a molecular weight cutoff (MWCO) of 5000, and then immersed in 200 ml of acetonitrile solvent to remove unreacted ferric chloride and monomer. The residue precipitated within the permeation membrane was washed with methanol and dried at 60°C for 12 hours to obtain conductive polymer (A). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of conductive polymer (A) were approximately 99,000 g / mol and 28,000 g / mol, respectively. The oxidation potential of the conductive polymer was approximately 3.95 V (based on Li / Li). + ).

[0253] Preparation Example 3. Polydopamine-coated conductive particles Use carbon black particles (IMERYS, C-NERGY) TM Super C65 was used as the conductive particles. The average particle size (D50 particle size) of the conductive particles was approximately 60 nm. DHC (dopamine hydrochloride) (CAS No. 62-31-7) was added to a buffer solution and stirred at room temperature (approximately 25°C). A 0.1 M pH 8.5 Tris buffer product from BIOSESANG was used as the buffer solution. The final molar concentration of DHC in the solution was approximately 2 mg / mL. The conductive particles were dispersed in the mixture of buffer solution and DHC at a concentration of approximately 4 mg / mL (sonicated for 1 hour) and stirred for an additional approximately 18 hours to form a polydopamine coating on the conductive particles. After filtration under reduced pressure using a paper filter, the resulting particles were vacuum dried to obtain polydopamine-coated conductive particles.

[0254] Example 1. An Al foil with a thickness of approximately 15 μm was used as the current collector.

[0255] The conductive polymer (A) of Preparation Example 2 and the conductive particles (P) of Preparation Example 3 were mixed at a weight ratio of 8:2 (A:P). The mixture was dispersed in a solvent (chloroform) at a concentration of approximately 2% by weight to prepare a coating solution. The coating solution was applied to the current collector by bar coating and heat-treated (dried) at 140°C for approximately 4 minutes, followed by heat-treated (annealed) again at 130°C for approximately 1 hour to form a polymer layer with a thickness of approximately 300 nm.

[0256] When measured using the above method, the oxidation potential of the polymer layer is approximately 3.45V.

[0257] An active material layer is formed on the polymer layer. The active material layer is formed as follows: A slurry containing electrode active material (75:1:1:23 by weight), carbon-based conductive material (ECP (Kejtien Black) 0.5%, SFG (Trimrex graphite) 0.4%, DB (Denka carbon black) 0.4%), PVDF (polyvinylidene fluoride), and NMP (N-methyl-2-pyrrolidone) in a weight ratio of 75:1:1:23 (electrode active material: conductive material: PVDF: NMP), carbon-based conductive material (ECP (Kejtien Black) 0.5%, SFG (Trimrex graphite) 0.4%, DB (Denka carbon black) 0.4%), PVDF (polyvinylidene fluoride), and NMP (N-methyl-2-pyrrolidone)) is coated onto the polymer layer to a thickness of approximately 90 μm using a doctor blade. It is dried at room temperature (approximately 25°C) and then further dried under vacuum at 120°C. Subsequently, rolling is performed to achieve a porosity of approximately 25%, thereby fabricating the electrode. As the electrode active material, NCM (Li[Ni)) is used. x Co (1-x) / 2 Mn (1-x) / 2 O2, x = 0.8 (Oxidation potential: approximately 3.7V).

[0258] Example 2. Except for preparing the coating solution by mixing the conductive polymer (A) of Preparation Example 2 and the conductive particles (P) of Preparation Example 3 in a weight ratio of 6:4 (A:P), the polymer layer and electrode were manufactured in the same manner as in Example 1. When measured by the above method, the oxidation potential of the polymer layer was approximately 3.41V.

[0259] Example 3. Except for preparing the coating solution by mixing the conductive polymer (A) of Preparation Example 2 and the conductive particles (P) of Preparation Example 3 in a weight ratio of 5:5 (A:P), the polymer layer and electrode were manufactured in the same manner as in Example 1. When measured by the above method, the oxidation potential of the polymer layer was approximately 3.37V.

[0260] Comparative Example 1. The electrodes were manufactured in the same manner as in Example 1, except that no polymer layer was formed.

[0261] Compare Example 2. Except that the coating solution was prepared using only the conductive polymer (A) of Preparation Example 2 and not the conductive particles of Preparation Example 3, the polymer layer and electrode were manufactured in the same manner as in Example 1. When measured by the above method, the oxidation potential of the polymer layer was approximately 3.72V.

[0262] For the fabricated electrode, the oxidation potential (Vs) of the polymer layer was measured (based on Li / Li). + ), oxidation potential (Va) of electrode active material (based on Li / Li + The results for ΔV, DC resistance, AC impedance, and PTC effect are summarized in Table 1 below. ΔV is calculated using the equation 100×(Va-Vs) / Va (Va: oxidation potential of the electrode active material, Vs: oxidation potential of the polymer layer). In Table 1, the unit of oxidation potential is V.

[0263] [Table 1] Table 2 below summarizes the capacity measured under various conditions based on charge / discharge tests.

[0264] [Table 2] According to the results in Table 2, in the case of the embodiment, the characteristics are the same as those of Comparative Example 1 without the application of a polymer layer. However, in the case of Comparative Example 2 without the application of conductive particles and without adjusting the oxidation potential relative to the electrode active material, it can be confirmed that a potential drop occurs during the discharge process due to the increase in the C rate.

[0265] Table 3 below summarizes the room temperature discharge capacity C based on the high-temperature discharge capacity reduction rate measurement method. 25 and high temperature discharge capacity C 130 In Table 3, the reduction rate is calculated as 100 × (C) 25 -C 130 ) / C 25 .

[0266] [Table 3] Table 3 confirms that when the electrode according to this application is used, the discharge capacity reduction rate is high under high temperature conditions, thus ensuring stability under abnormal conditions.

[0267] In Comparative Example 2, a decrease in discharge capacity was confirmed under high temperature conditions, but the discharge capacity at room temperature under the same conditions was lower than that in the Example.

Claims

1. An electrode comprising: a current collector; an active material layer formed on the current collector and including an electrode active material; and a polymer layer located between the current collector and the active material layer and containing an electrically conductive polymer and an electrically conductive material, wherein ΔV of the following Equation 1 is greater than 5% and is 20% or less: The polymer layer has an oxidation potential based on Li / Li + which is lower than the oxidation potential of the electrode active material based on Li / Li + .

2. The electrode of claim 1, wherein, [Equation 1] ΔV = 100 × (Va - Vs) / Va an absolute value of ΔR4 of the following Equation 4 is 50% or more: [Equation 5] ΔR4 = 100 × (C1-C3) / C1 wherein Va is the oxidation potential of the electrode active material based on Li / Li + Vs is the oxidation potential of the polymer layer based on Li / Li + +0.1 V.

3. The electrode of claim 1, wherein, The polymer layer has an oxidation potential of 5.0 V or less based on Li / Li + + 4. The electrode of claim 1, wherein, wherein C1 is a discharge capacity at 25°C and C3 is a discharge capacity after storage at 130°C for 10 minutes. the electrically conductive polymer has a long-chain hydrocarbon functional group. the electrically conductive polymer contains a first hydrocarbon functional group having 10 or more carbon atoms and a second hydrocarbon functional group having 9 or less carbon atoms as the long-chain hydrocarbon functional group. the electrically conductive polymer contains a functional group of the following Formula 1:

5. The electrode of claim 1, wherein, [Formula 1] wherein L1 is a single bond, an alkylene group, or an alkylidene group, L2 is an alkylene group or an alkylidene group, R1 is hydrogen or an alkyl group, and m is a number in the range of 1 to 10.

6. The electrode of claim 5, wherein, the electrically conductive polymer contains a thiophene monomer unit and a non-thiophene monomer unit.

7. The electrode of claim 1, wherein, the non-thiophene monomer unit is an aromatic monomer unit or a nitrogen-containing heterocyclic monomer unit. a molar ratio of the thiophene monomer unit in the electrically conductive polymer is 70 mol% or more, and 0.05 mol or more of the non-thiophene monomer unit is present per 1 mol of the thiophene monomer unit.

11. The electrode according to claim 8, wherein the non-thiophene monomer unit is at least one unit selected from the following Formulae 10 to 15:

8. The electrode of claim 1, wherein, [Formula 10] [Formula 11] [Formula 12] [Formula 13] [Formula 14] [Formula 15] wherein the unit of Formula 15 is unsubstituted or substituted with one or more selected from the group consisting of an alkyl group, an alkenyl group, an alkoxy group, an aryl group, and a halogen.

9. The electrode of claim 8, wherein, the electrically conductive material is a carbon particle, a carbon fiber, graphene, graphite, carbon black, or a carbon nanotube.

10. The electrode of claim 8, wherein, the electrically conductive material is surface-treated with a polyphenol-based compound.

14. An electrode assembly comprising the electrode according to any one of claims 1 to 13.

15. A secondary battery comprising the electrode assembly according to claim 14. wherein R 18 , R 19 , and R 20 are each independently hydrogen, a polar functional group, or a hydrocarbon functional group, ​ wherein L 11 is a single bond, alkylene, alkylidene, O, or NR 1 wherein R 1 is hydrogen, alkyl, alkenyl, or aryl, ​ wherein X1is S, O or NR 1 wherein R 1 is hydrogen, alkyl, alkenyl or aryl, R 25 to R 28 are each independently hydrogen, alkyl, alkenyl, alkoxy, aryl or halogen, ​ wherein R 29 to R 34 each independently is hydrogen, alkyl, alkenyl, alkoxy, aryl, hydroxyl, or halogen, ​ wherein X2is CR a R b or NR 1 wherein R a , R b and R 1 are each independently hydrogen, alkyl, alkenyl or aryl, and the unit of the above formula 14 is unsubstituted or substituted by one or more selected from the group consisting of alkyl, alkenyl, alkoxy, aryl and halogen, ​ ​ 12. The electrode of claim 1, wherein, ​ 13. The electrode of claim 1, wherein, ​ ​ ​

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