Current collector

Abstract

The present application relates to a current collector and a use thereof. The present application may provide a current collector and a use thereof, wherein the current collector may form an electrode that exhibits excellent electrical characteristics, including low resistance, to give no influence on the performance and operation of secondary batteries in a normal condition, and ensures stability by blocking the current flow through an electrode assembly by increasing resistance in an abnormal condition.

Description

Whole house

[0001] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2023-0108436, dated August 18, 2023, the entire contents of which are incorporated herein by reference.

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

[0003] Energy storage technology is expanding its application areas to include mobile phones, tablets, laptops, and even electric vehicles.

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

[0005] As major developed countries curb the production of vehicles powered by internal combustion engines to address global warming and air pollution, major automakers are also developing various electric vehicles. As such, the importance of secondary batteries with high energy density, high discharge voltage, and output stability as power sources is increasing.

[0006] In line with the above trend, the frequency of fire or explosion accidents caused by overcharging, exposure to high temperatures, or external impact in devices or automobiles that use secondary batteries as an energy source is also increasing.

[0007] A major cause of these accidents is known to be a short circuit, which occurs when the positive and negative electrodes within the electrode assembly come into direct contact, primarily due to external stimuli. This short circuit can occur when a secondary battery is overcharged, exposed to high temperatures, or exposed to external stimuli, resulting in shrinkage of the separator due to an increase in the battery's internal temperature, or destruction of the battery's internal structure due to external impact.

[0008] When a short circuit occurs, the movement of lithium ions and electrons is concentrated at the point where the positive and negative electrodes are in direct contact, potentially accelerating internal heat generation. This is known to generate gases and other substances within the battery, causing its volume to expand and increasing the risk of fire.

[0009] The present application relates to a current collector, an electrode, and uses thereof. The purpose of this application is to provide a current collector and electrode that exhibit low resistance and excellent electrical properties under normal conditions, thus not affecting the performance and operation of a secondary battery, while ensuring stability through increased resistance under abnormal conditions. The present application also aims to provide uses for the current collector and electrode.

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

[0011] In the case where the measurement temperature affects the properties mentioned in this specification, the properties are those measured at room temperature, unless otherwise specified. The unit of temperature mentioned in this specification is Celsius (℃), unless otherwise specified.

[0012] The term atmospheric pressure in this specification means a natural pressure that is neither pressurized nor depressurized, and can typically mean a pressure of about 730 mmHg to 790 mmHg.

[0013] In cases where the measurement pressure affects the properties mentioned in this specification, the properties are properties measured at the atmospheric pressure, unless otherwise specified.

[0014] In cases where the measured humidity affects the properties mentioned in this specification, unless otherwise specified, the properties are properties measured at standard humidity.

[0015] In this specification, standard state humidity means a relative humidity within the range of 40% to 60%, for example, a relative humidity of about 40%, 45%, 50%, 55% or 60%.

[0016] In this specification, the term normal state means the normal operating state (e.g., normal charging or discharging state of a secondary battery) and / or storage state of an electrical / electronic device such as a secondary battery.

[0017] The term "abnormal state" as used herein refers to a state in which abnormal heat generation, ignition, and / or explosion occurs in an electrical / electronic device such as a secondary battery, or a state in which the risk of such abnormal heat generation, ignition, and / or explosion increases. For example, a state in which abnormal heat generation, ignition, or explosion occurs in a secondary battery due to a short circuit phenomenon, or a dangerous state in which the risk of such heat generation, ignition, or explosion increases may be considered an abnormal state.

[0018] The present application relates to a current collector. The current collector may be a current collector for an electrode.

[0019] The current collector for an electrode of the present application may include a current collector body and a polymer layer formed on the current collector body. The current collector may be used to form an electrode. For example, an electrode formed using the current collector for an electrode may include the current collector for an electrode and an active material layer formed on the polymer layer of the current collector. Fig. 1 is an exemplary cross-sectional view of a current collector including a current collector body (100) and a polymer layer (200), and Fig. 2 is an exemplary cross-sectional view showing an electrode in which an active material layer (300) is formed on the polymer layer (200) of the current collector.

[0020] In the current collector or electrode, the current collector body (100) and the polymer layer (200), and the polymer layer (200) and the active material layer (300), may be in contact with each other as shown in the drawing. In some cases, other elements may exist between the current collector body (100) and the polymer layer (200) or between the polymer layer (200) and the active material layer (300). In addition, although the drawing shows a case where the active material layer (300) exists only on one side of the current collector body (100), the active material layer (300) may exist on both sides of the current collector body (100). In this case, the polymer layer (200) may exist in two layers between each of the active material layers (300) present on both sides of the current collector body (100) and the current collector body (100), or may exist in one layer between any one of the active material layers (300) present on both sides and the current collector body (100).

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

[0022] The polymer layer can be designed to exhibit a so-called positive temperature coefficient (PTC) effect. This polymer layer can exhibit changes in conductivity depending on changes in temperature and / or applied voltage. Accordingly, the polymer layer can variably control the movement of charges through the electrode depending on temperature.

[0023] By applying such a polymer layer, the electrode having the current collector of the present application can be applied to a secondary battery or the like, and exhibit excellent electrical characteristics including low resistance in a normal state, and can secure stability through an increase in resistance in an abnormal state.

[0024] In order for a polymer layer to be applied to an electrode and exhibit the above-described effect, the tendency of the PTC effect exhibited by the polymer layer must be controlled. The PTC effect is an effect in which resistance increases in proportion to temperature. In order for an electrode to which a polymer layer with the PTC effect is applied to operate stably and ensure stability under abnormal conditions, the oxidation potential of the polymer layer, the electrical characteristics before the resistance increases due to the PTC effect, and the point in time when the resistance increases due to the PTC effect must be adjusted.

[0025] For example, if the oxidation potential of a polymer layer is higher than that of the electrode active material, repeated charging and discharging under normal conditions may occur, and a potential drop may occur during high-speed charging and discharging. Furthermore, if the resistance of the polymer layer is excessively high under normal conditions, charge movement may be restricted, adversely affecting the operation of the secondary battery. Furthermore, if the temperature at which the PTC effect manifests is within the normal temperature range, the performance of the secondary battery may not be properly realized.

[0026] The polymer layer disclosed in this specification has a PTC effect, the timing of the PTC effect's onset is controlled, and maintains a stable oxidation potential and electrical properties before the PTC effect's onset.

[0027] To achieve this PTC effect, a specific conductive polymer can be introduced into the polymer layer. For example, the electrical properties of the polymer layer are influenced by the state of the conductive polymer. For example, when the conductive polymer is doped, the polymer layer may exhibit low resistance, and when it is dedoped, the polymer layer may exhibit high resistance. In the present application, the conductive polymer can be adjusted to switch between the doped and dedoped states at a necessary time in response to temperature and / or voltage.

[0028] In the present application, as described later, a conductive polymer having a relatively long hydrocarbon chain (long-chain hydrocarbon functional group) is applied, and by controlling the drying or annealing temperature during the polymer layer formation process, a suitable PTC effect (e.g., inducing an increase in resistance of the polymer layer at a desired temperature (the temperature of the ideal state of the battery)) can be secured.

[0029] In addition, by introducing a conductive material into the polymer layer and dispersing it uniformly, oxidation potential and electrical properties can be appropriately maintained.

[0030] For example, the current collector or the electrode including the current collector may exhibit low resistance at room temperature (about 25°C). For example, the AC impedance resistance at 25°C confirmed by the polymer layer, current collector or electrode may be below a certain level. Accordingly, stable operation or storage of the secondary battery may be possible in a normal state. The upper limit of the AC impedance resistance may be about 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 9, 8.5 or 8, and the lower limit may be about 0, 2, 4, 6, 8 or 10. The unit of the AC impedance resistance is Ω. The AC impedance resistance may be within a range that is less than or equal to any one upper limit selected from the upper limits listed above; or within a range that is less than or equal to any one upper limit selected from the upper limits listed above and greater than or equal to any one lower limit selected from the lower limits listed above. The AC impedance resistance is a resistance substantially confirmed in a coin cell to which the polymer layer, current collector layer, or electrode is applied, and the method for measuring the AC impedance resistance is according to the method described in “5. AC Impedance Resistance Measurement” of the Examples section of the present specification.

[0031] The polymer layer, current collector, or electrode including the polymer layer, exhibits low resistance as described above at room temperature (approximately 25°C), and exhibits a rapid increase in resistance at a required time. For example, the polymer layer, current collector, or electrode may have △R within a certain range according to the following equation 1.

[0032] [Formula 1]

[0033] △R = 100 × (R 130 - R 25 ) / R 25

[0034] R in Equation 1 25 is the AC impedance resistance at 25℃, and R 130 is the AC impedance resistance at 130℃. The AC impedance resistance R 25 and R 130 Silver is the resistance confirmed in the coin cell to which the polymer layer, current collector layer or electrode is applied, and the measurement method thereof is according to the method described in “5. AC impedance resistance measurement” of the Example section of this specification.

[0035] The lower limit of △R in Equation 1 may be about 200%, 500%, 700%, 800%, 900%, 950%, 1,000%, 1,100%, 1,150%, 1,200%, 1,500%, 1,700%, 1,800%, 1,900%, 2,000%, 2,100%, or 2,200%, and the upper limit may be about 10,000%, 7,000%, 5,000%, 4,000%, 3,000%, 2,500%, 2,400%, 2,300%, or 2,200%. The above △R may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above.

[0036] The above characteristics are exhibited by the polymer layer described above.

[0037] According to the PTC effect of the polymer layer, the polymer layer, the current collector or the electrode may have △C within a certain range according to the following equation 1.

[0038] [Formula 2]

[0039] △C = 100 × (C 25 -C 130 ) / C 25

[0040] C in Equation 2 25 is the discharge capacity at 25℃, and C 130 is the discharge capacity after 10 minutes of storage at 130℃. The above discharge capacity C 25 and C 130 Silver is the discharge capacity confirmed in the coin cell to which the polymer layer, current collector layer or electrode is applied, and the measurement method thereof is according to the contents described in “7. Measurement of room temperature and high temperature discharge capacity” of the Examples section of this specification.

[0041] The lower limit of the above △C may be about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85%, and the upper limit may be about 500%, 450%, 400%, 350%, 300%, 250%, 200%, 150%, 100%, 95%, 90%, 85%, or 80%. The above △C may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above.

[0042] The above characteristics can be achieved by introducing a polymer layer as described below.

[0043] As the above-mentioned current collector body, one that is commonly used as a current collector body for a positive or negative electrode can be used without any special restrictions.

[0044] As for the current collector body, as long as it is conductive and does not cause chemical changes in an application device such as a secondary battery, its type, size, shape, etc. are not particularly limited. Examples of materials that can be used as the current collector body include copper, aluminum, stainless steel, nickel, titanium, or calcined carbon, or materials whose surfaces are surface-treated with carbon, nickel, titanium, or silver, etc. of copper, aluminum, or stainless steel, etc. The current collector body may be in the form of a film, sheet, foil, net, porous body, foam, or non-woven body containing the above material. In some cases, a known surface treatment may be performed on the surface of the current collector body to improve adhesion to other layers such as a polymer layer or an active material layer.

[0045] The entire body of the collector may have a thickness typically within a range of 3 μm to 500 μm, but is not limited thereto.

[0046] A polymer layer exists on one or both sides of the above-mentioned collector body.

[0047] The term polymer layer as used herein refers to a layer containing a polymer. For example, the lower limit of the content of the polymer contained in the polymer layer may be about 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt% or 95 wt%, and the upper limit may be about 100 wt%, 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt% or 50 wt%. The content is the content of the polymer based on the total weight of the polymer layer. The content is within a range that is equal to or greater than any lower limit selected from the lower limits listed above; Or it may be a range that is less than or equal to any upper limit selected from the upper limits listed above, and greater than or equal to any lower limit selected from the lower limits listed above.

[0048] The polymer layer may not be a so-called active material layer of the electrode. Therefore, the content of the electrode active material within the polymer layer can be controlled. For example, the upper limit of the content of the electrode active material within the polymer layer may be about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, 0.005 wt%, or 0.001 wt%, and the upper limit may be 0 wt%. The content is the content of the polymer based on the total weight of the polymer layer. The content is within a range that is equal to or less than any upper limit selected from the upper limits listed above; Or, it may be a range that is less than or equal to any upper limit selected from the upper limits listed above, and greater than or equal to any lower limit selected from the lower limits listed above. The specific type of the electrode active material is described below.

[0049] The polymer included in the polymer layer may be a conductive polymer. As is known, a conductive polymer is a polymer that exhibits conductivity due to a conjugated system and / or doping of a polymer chain. In one example, the conductive polymer may be a polymer whose conductivity changes due to doping and dedoping. In one example, the conductive polymer may be a conductive copolymer. A conductive copolymer is a type of conductive polymer, and is distinguished from a conductive polymer in the form of a homopolymer in that it is a conductive polymer that includes two or more types of monomer units.

[0050] By using a specific conductive polymer described below, the PTC effect exhibited by the polymer can be adjusted according to the purpose.

[0051] The oxidation potential of the conductive polymer or polymer layer can be controlled according to the purpose. In the present specification, the oxidation potential is lithium and lithium ion (Li / Li+ ) is the oxidation potential measured based on the standard.

[0052] The lower limit of the oxidation potential may be about 2 V, 2.1 V, 2.2 V, 2.3 V, 2.4 V, 2.5 V, 2.6 V, 2.7 V, 2.8 V, 2.9 V, 3 V, 3.1 V, 3.2 V, 3.3 V, 3.4 V, 3.5 V, 3.6 V or 3.7 V, and the upper limit may be about 6 V, 5.5 V, 5 V, 4.9 V, 4.8 V, 4.7 V, 4.6 V, 4.5 V, 4.4 V, 4.3 V, 4.2 V, 4.1 V, 4.0 V, 3.9 V, 3.8 V, 3.7 V, 3.6 V or 3.5 V. The oxidation potential may be within a range that is less than or equal to any one of the upper limits listed above; within a range that is greater than or equal to any one of the lower limits listed above; or within a range that is less than or equal to any one of the upper limits listed above and greater than or equal to any one of the lower limits listed above. By adjusting the oxidation potential within the above range, the desired properties can be effectively secured.

[0053] The conductive polymer may have a weight average molecular weight within a predetermined range. The lower limit of the weight average molecular weight of the conductive polymer may be about 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, or 60,000, and the upper limit may be about 200,000, 150,000, 100,000, 95,000, 90,000, 85,000, 80,000, 75,000, 70,000, 65,000, 60,000, 55,000, or 50,000. The unit of the weight average molecular weight is g / mol. The weight average molecular weight may be within a range that is less than or equal to any one of the upper limits listed above; within a range that is greater than or equal to any one of the lower limits listed above; or within a range that is less than or equal to any one of the upper limits listed above and greater than or equal to any one of the lower limits listed above. By using a conductive polymer having the above weight average molecular weight, a polymer layer, a current collector, and an electrode having desired properties can be effectively formed.

[0054] The molecular weight distribution of the conductive polymer, i.e., the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn, may be within a predetermined range. The lower limit of the molecular weight distribution may be about 2, 2.5, 3, 3.5, or 4, and the upper limit may be about 10, 9, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, or 3.5. The molecular weight distribution may be within a range that is less than or equal to any one upper limit selected from the upper limits listed above; within a range that is greater than or equal to any one lower limit selected from the lower limits listed above; or within a range that is less than or equal to any one upper limit selected from the upper limits listed above and greater than or equal to any one lower limit selected from the lower limits listed above. By using a conductive polymer having the above molecular weight distribution, a polymer layer, current collector, and electrode having the desired properties can be effectively formed.

[0055] When a conductive polymer has the above-described molecular weight characteristics, the desired PTC effect can be efficiently controlled. As described below, the PTC effect by the conductive polymer can be expressed by adjusting the de-doping efficiency by vibration of a functional group (such as a long-chain hydrocarbon functional group described below) included in the conductive polymer at an increased temperature. The type of vibration of the functional group varies depending on the carbon number of the functional group, as described below, and also varies depending on the size and size distribution of the polymer including the functional group. The weight-average molecular weight and molecular weight distribution reflect the size and size distribution. The weight-average molecular weight and molecular weight distribution can be measured by the method described in "2. GPC (Gel Permeation Chromatograph)" of the Examples section of this specification.

[0056] The above conductive polymer may be polythiophene.

[0057] In this specification, the term polythiophene refers to a polymer containing a certain level or more of thiophene monomer units. The number of moles M of the thiophene monomer units is compared to the number of moles M of all monomer units contained in the polythiophene. T The ratio of 100×M T The lower limit of / M may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol% or 90 mol%, and the upper limit may be about 100 mol%, 95 mol% or 90 mol%. The range may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above.

[0058] In this specification, a monomer unit means a form in which a monomer is polymerized and included in a polymer, and a thiophene monomer means a monomer of the thiophene series and a monomer containing a thiophene skeleton.

[0059] The conductive polymer may include a long-chain hydrocarbon functional group or a monomer unit having the long-chain hydrocarbon functional group (hereinafter referred to as unit A). The conductive polymer may be polythiophene. In this case, the monomer having the long-chain hydrocarbon functional group may be a thiophene monomer.

[0060] In this specification, the term long-chain hydrocarbon functional group means a monovalent hydrocarbon group having a carbon number greater than or equal to a certain level or a monovalent functional group including a hydrocarbon structure having a carbon number greater than or equal to the certain level.

[0061] For example, the lower limit of the number of carbon atoms present in the long-chain hydrocarbon functional group (i.e., the number of carbon atoms in the monovalent hydrocarbon group or hydrocarbon structure) may be about 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, and the upper limit may be about 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, or 4. The number of carbon atoms may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above.

[0062] The above carbon number may be the carbon number of a straight-chain hydrocarbon chain present in the long-chain hydrocarbon functional group. That is, the monovalent hydrocarbon group or hydrocarbon structure present in the long-chain hydrocarbon functional group may have a straight-chain structure or a branched-chain structure, and even in the case of a branched-chain structure, the carbon number constituting the longest straight-chain chain in the branched-chain structure may be within the above range. For example, if the branched-chain structure is a 2-ethylhexyl group, the carbon number constituting the longest straight-chain chain is 6.

[0063] Examples of the long-chain hydrocarbon functional group include at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylcarbonyl group, and an alkylcarbonyloxy group. In a suitable example, the long-chain hydrocarbon functional group may be an alkyl group and / or an alkoxy group.

[0064] The number of carbon atoms in the alkyl group, alkenyl group and alkynyl group, and the alkyl group present in the alkoxy group, alkylcarbonyl group and alkylcarbonyloxy may be in the range of the number of carbon atoms present in the long-chain hydrocarbon functional group (i.e., the number of carbon atoms in the monovalent hydrocarbon group or hydrocarbon structure).

[0065] For example, the alkyl group, alkenyl group and alkynyl group, and the alkyl group present in the alkoxy group, alkylcarbonyl group and alkylcarbonyloxy may have a straight or branched chain structure, and in the case of a branched chain, the number of carbon atoms constituting the longest straight chain in the branched chain structure may be within the above range.

[0066] The above long-chain hydrocarbon functional group, such as an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylcarbonyl group or an alkylcarbonyloxy group, may be optionally substituted with one or more substituents.

[0067] These long-chain hydrocarbon functional groups are functional groups that can impart appropriate mobility to the monomer or the conductive polymer itself during the polymerization process of the conductive polymer. The monomer containing such a long-chain hydrocarbon functional group imparts appropriate mobility to the monomer mixture and also diffuses within the monomer mixture, thereby enabling polymerization to occur with excellent efficiency. In addition, the conductive polymer having a long-chain hydrocarbon functional group can enable the stable and uniform formation of a polymer layer between the current collector and the active material layer through appropriate mobility.

[0068] The long-chain hydrocarbon functional group may be appropriately oriented during the drying or annealing process applied in the formation process of the polymer layer, thereby enabling the control of a PTC effect suitable for the polymer. The long-chain hydrocarbon functional group exhibits enhanced vibrational energy at increased temperature, thereby controlling the efficiency of dedoping of anions bonded to the polymer. This dedoping induces an increase in resistance. The dedoping efficiency may be controlled by the length and / or amount of the long-chain hydrocarbon functional group. For example, under the same temperature, the vibrational energy of a relatively long chain is greater than that of a relatively short chain, and thus, the desired PTC effect can be set by controlling the type, length, and / or ratio of the long-chain hydrocarbon functional group.

[0069] For example, in order to properly implement the above effect, the mole number M of the monomer unit (unit A) having the long-chain hydrocarbon functional group is compared to the mole number M of the total monomer units of the conductive polymer. L The ratio of 100×M L / M can be adjusted. For example, the above ratio is 100×M L The lower limit of / M may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol% or 95 mol%, and the upper limit may be about 99 mol%, 98 mol%, 96 mol%, 95 mol%, 94 mol%, 93 mol%, 92 mol%, 91 mol% or 90 mol%. The ratio may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above. The ratio 100×M LThe closer the upper and lower limits of / M are to the ratio (approximately 90 mol%) presented in the examples of this specification, the more effectively the desired effect can be achieved.

[0070] The conductive polymer may include first and second hydrocarbon functional groups having different carbon numbers as the long-chain hydrocarbon functional groups.

[0071] The first hydrocarbon functional group is a functional group having a relatively large number of carbon atoms among the long-chain hydrocarbon functional groups. The lower limit of the carbon atoms of the first hydrocarbon functional group may be about 10, 11, or 12, and the upper limit may be about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10. The carbon atoms of the first hydrocarbon functional group may be within a range that is equal to or greater than any lower limit selected from the lower limits listed above; or may be within a range that is equal to or less than any upper limit selected from the upper limits listed above and equal to or greater than any lower limit selected from the lower limits listed above. The closer the lower limit of the number of carbon atoms of the first hydrocarbon functional group is to the number (12) presented in the examples of this specification, the more effectively the desired effect can be achieved.

[0072] This first hydrocarbon functional group exhibits enhanced vibrational energy at elevated temperatures, thereby controlling the dedoping efficiency of the conductive polymer. The onset temperature of dedoping of the conductive polymer can be controlled through the content of the first hydrocarbon functional group or the combination of the second hydrocarbon functional group described below.

[0073] The second hydrocarbon functional group is a functional group having a relatively small number of carbon atoms among the long-chain hydrocarbon functional groups. The lower limit of the carbon atoms of the second hydrocarbon functional group may be about 3, 4, 5, 6, 7, or 8, and the upper limit may be about 9, 8, 7, or 6. The carbon atoms of the second hydrocarbon functional group may be within a range that is less than or equal to any upper limit selected from the upper limits listed above; or within a range that is less than or equal to any upper limit selected from the upper limits listed above and greater than or equal to any lower limit selected from the lower limits listed above. The closer the lower limit and the upper limit of the carbon atoms of the second hydrocarbon functional group are to the value (6) presented in the examples of the present specification, the more effectively the desired effect can be exhibited.

[0074] This second hydrocarbon functional group dilutes the effect of the vibrational energy exhibited by the first hydrocarbon functional group at a given temperature. Therefore, the first hydrocarbon functional group has the effect of lowering the onset point of the PTC effect, while the second hydrocarbon functional group has the effect of diluting the first hydrocarbon functional group.

[0075] The number of carbon atoms in each of the first and second hydrocarbon functional groups may 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 may each independently be at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylcarbonyl group, and an alkylcarbonyloxy group, and may be an alkyl group and / or an alkoxy group in an appropriate example, and the number of carbon atoms may be the number of carbon atoms in the alkyl group, the alkenyl group, and the alkynyl group, and the alkyl group present in the alkoxy group, the alkylcarbonyl group, and the alkylcarbonyloxy group.

[0076] The alkyl group present in the above alkyl group, alkenyl group and alkynyl group, and the alkoxy group, alkylcarbonyl group and alkylcarbonyloxy may have a straight or branched chain structure. In the case of a straight chain, the total number of carbon atoms may be within the above range, and in the case of a branched chain, the number of carbon atoms constituting the longest straight chain in the branched chain structure may be within the above range.

[0077] As described above, the carbon number of the long-chain hydrocarbon functional group is related to the vibration characteristics due to applied heat energy, and when the carbon number changes, the vibration characteristics also change, and the vibration characteristics are further linked to the PTC characteristics of the conductive polymer. In the conductive polymer of the present application, the first hydrocarbon functional group mainly plays a role in controlling the temperature at which the PTC effect is expressed, i.e., the temperature at which an increase in resistance occurs, and the second hydrocarbon functional group can play a role in suppressing an increase in resistance at relatively low temperatures.

[0078] In the conductive polymer, the ratio of the sum of the number of moles M1 of the monomer unit having the first hydrocarbon functional group and the number of moles M2 of the monomer unit having the second hydrocarbon functional group to the number of moles M of the total monomer units of the conductive polymer, M1+M2, 100×(M1+M2) / M, is the ratio of the unit A described above, 100×M L / Can be adjusted within the same range as M.

[0079] The lower limit of the ratio M2 / M1 of the mole number M2 of the monomer unit having the second hydrocarbon functional group in the conductive polymer to the mole number M1 of the monomer unit having the first hydrocarbon functional group may be about 0.01, 0.05, 0.1, 0.5, 1, 1.5 or 2, and the upper limit may be about 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.7. The above ratio may have a range between being less than or equal to any upper limit selected from the upper limits listed above, being greater than or equal to any lower limit selected from the lower limits listed above, or being less than or equal to any upper limit selected from the upper limits listed above and being greater than or equal to any lower limit selected from the lower limits listed above. The closer the lower limit and the upper limit of the ratio M2 / M1 are to the ratio (approximately 0.5) presented in the embodiments of the present specification, the more effectively the desired effect can be achieved.

[0080] Under such a ratio, the conductive polymer or the polymer layer exhibits an appropriate PTC (Positive Temperature Coefficient) effect, exhibits stable electrical characteristics at a normal temperature, and the surface characteristics of the polymer layer are controlled to ensure excellent adhesion to the electrode or current collector.

[0081] The conductive polymer may include a polar functional group or a monomer unit having the polar functional group (hereinafter referred to as unit B) together with the long-chain hydrocarbon functional group or unit A. The monomer having the polar functional group may be a thiophene monomer.

[0082] As used herein, the term "polar functional group" refers to a functional group containing one or more polar atoms, such as oxygen and / or nitrogen. Examples of such functional groups include, but are not limited to, a carboxyl group, a hydroxyl group, an amino group, a cyano group, a nitro group, an ether group, or a functional group represented by the following chemical formula 3. In one example, the polar functional group may be a functional group represented by the following chemical formula 3.

[0083] [Chemical Formula 3]

[0084]

[0085] In chemical formula 3, L4 is a single bond, an alkylene group, or an alkylidene group, L3 is an alkylene group or an alkylidene group, R5 is hydrogen or an alkyl group, and n is any number.

[0086] In chemical formula 3, L4 being a single bond means that L4 does not exist and the oxygen atom between L4 and L3 is directly connected to the monomer.

[0087] The alkyl group of R5 in Chemical Formula 3 may be, for example, an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or a methyl group or an ethyl group. The alkyl group may be linear, branched, or cyclic, and may be linear or branched, as appropriate. The alkyl group may be optionally substituted with one or more substituents.

[0088] In this specification, the term alkylene group means a divalent functional group formed by the removal of hydrogen atoms from two different carbon atoms in an alkane, and the term alkylidene group means a divalent functional group formed by the removal of two hydrogen atoms from one carbon atom in an alkane.

[0089] The alkylene groups of L3 and L4 in Chemical Formula 3 may each be, in one example, an alkylene group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, or an ethylene group or a propylene group. The alkylene group may be linear, branched, or cyclic, and may be linear or branched, as appropriate. The alkylene group may be optionally substituted with one or more substituents.

[0090] The alkylidene groups of L3 and L4 in chemical formula 3 may each be, in one example, 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 a methylidene group, an ethylylene group, or a propylidene group. The alkylidene group may be linear, branched, or cyclic, and may be linear or branched, as appropriate. The alkylidene group may be optionally substituted with one or more substituents.

[0091] In chemical formula 3, the lower limit of n may be 1, 2, 3, or 4, and the upper limit may be 10, 9, 8, 7, 6, 5, 4, or 3. The n may be within a range that is less than or equal to any one upper limit selected from the upper limits listed above, and greater than or equal to any one lower limit selected from the lower limits listed above.

[0092] By applying the above polar functional group, a polymer layer can be bonded to another layer with appropriate bonding strength, and a layer of such conductive polymer can be uniformly formed to efficiently achieve the desired protective function. In addition, the above polar functional group can also play a role in suppressing the PTC effect from appearing at relatively low temperatures.

[0093] The mole numbers of the polar functional groups and long-chain hydrocarbon functional groups within the conductive polymer can be controlled to ensure an appropriate effect.

[0094] For example, the number of moles M of the long-chain hydrocarbon functional groups in the conductive polymer L and the number of moles of the polar functional group M P The ratio of M L / M P The lower limit of may be about 1, 5, 7, 8, 9, 10, 15, 16, 17, 18 or 19, and the upper limit may be about 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 or 10. The above ratio M L / M P It may be within a range that is less than or equal to any one of the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits listed above; or within a range that is less than or equal to any one of the upper limits listed above and greater than or equal to any one of the lower limits listed above. The ratio M L / M P The closer the upper and lower limits are to the ratio (about 9) presented in the examples of this specification, the more effectively the desired effect can be achieved.

[0095] The number of moles M of the above unit A in the conductive polymer A The number of moles M of the above unit B B Ratio for M A / M B Silver, the above ratio M L / M P can be adjusted within the same range. At this time, the confiscation M L Silver confiscation M A Becomes and confiscates M P is confiscated M B It becomes.

[0096] The total mole number M of the above units A and B relative to the total mole number M of all monomer units of the conductive polymer A +M B The ratio of 100×(M A +M B ) / M's lower limit may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol% or 95 mol%, and its upper limit may be about 100 mol%, 95 mol% or 90 mol%. The ratio may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above; or within a range that is equal to or less than any one upper limit selected from the upper limits listed above and equal to or greater than any one lower limit selected from the lower limits listed above.

[0097] The specific structure of the monomer included in the conductive polymer is not particularly limited as long as it is a thiophene monomer having the long-chain hydrocarbon functional group and / or polar functional group described above.

[0098] For example, the conductive polymer may include a monomer unit of the following chemical formula 1 as the thiophene monomer unit.

[0099] [Chemical Formula 1]

[0100]

[0101] In chemical formula 1, R1 and R2 are each independently hydrogen, the polar functional group or the long-chain hydrocarbon functional group, and at least one of R1 and R2 may be the polar functional group or the long-chain hydrocarbon functional group.

[0102] In another example, in Chemical Formula 1, R1 and R2 can be linked to each other to form a divalent functional group of Chemical Formula 2 below.

[0103] [Chemical Formula 2]

[0104]

[0105] In chemical formula 2, each oxygen atom can be bonded to the carbon atom to which R1 is connected and the carbon atom to which R2 is connected in chemical formula 1.

[0106] In chemical formula 2, L1 and L2 are each independently a single bond, an alkylene group, or an alkylidene group, and R3 and R4 are each independently hydrogen, a polar functional group, or a long-chain hydrocarbon functional group, provided that at least one of R3 and R4 is a polar functional group or a long-chain hydrocarbon functional group.

[0107] In Chemical Formulas 1 and 2, the specific types of polar functional groups and long-chain hydrocarbon functional groups are as described above. As described above, as the long-chain hydrocarbon functional groups, the first and second hydrocarbon functional groups may be applied together. In this case, within the scope of Chemical Formula 1, a monomer unit having the first hydrocarbon functional group and a second monomer unit having the second hydrocarbon functional group may be used, and the ratio between them may also follow the above-described content.

[0108] The meaning that L1 or L2 in Chemical Formula 2 is a single bond is the same as in the case of L4 in Chemical Formula 3. The specific types of the alkylene group and alkylidene group of L1 and L2 in Chemical Formula 2 are the same as the alkylene group and alkylidene group in Chemical Formula 3.

[0109] The lower limit of the molar ratio of the monomer unit of the above chemical formula 1 relative to the molar number of all monomer units included in the above conductive polymer may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol% or 90 mol%, and the upper limit may be about 100 mol%, 95 mol% or 90 mol%. The range may be within a range that is equal to or greater than any lower limit selected from the lower limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above and equal to or greater than any lower limit selected from the lower limits listed above.

[0110] The above conductive polymer may simultaneously include, as monomer units, a monomer unit of the following chemical formula 4 and a monomer unit of the following chemical formula 5. The monomer unit of the following chemical formula 4 is an example of the above-described unit A, and the monomer unit of the following chemical formula 5 is an example of the above-described unit B.

[0111] [Chemical Formula 4]

[0112]

[0113] In chemical formula 4, R6 and R7 are each independently hydrogen or the long-chain hydrocarbon functional group, and at least one of R6 and R7 is the long-chain hydrocarbon functional group.

[0114] In another example, R6 and R7 of the above chemical formula 4 may be linked to each other to form a divalent functional group of the following chemical formula 6.

[0115] [Chemical Formula 6]

[0116]

[0117] In chemical formula 6, L5 and L6 are each independently a single bond, an alkylene group or an alkylidene group, and R 10 and R 11 are each independently hydrogen or the long-chain hydrocarbon functional group, R 10 and R 11 At least one of the above long-chain hydrocarbon functional groups.

[0118] The specific types of long-chain hydrocarbon functional groups in Chemical Formulas 4 and 6 are as described above. As described above, the long-chain hydrocarbon functional groups may be applied together with the first and second hydrocarbon functional groups. In this case, within the scope of Chemical Formula 4, a monomer unit having the first hydrocarbon functional group and a second monomer unit having the second hydrocarbon functional group may be used, and the ratio between them may also follow the above-described content.

[0119] The meaning of single bonds in chemical formula 6 and the specific types of alkylene and alkylidene groups are the same as in chemical formula 3.

[0120] [Chemical Formula 5]

[0121]

[0122] In Chemical Formula 5, R8 and R9 are each independently hydrogen or the polar functional group, and at least one of R8 and R9 may be the polar functional group. In another example, R8 and R9 in Chemical Formula 5 may be linked to each other to form a divalent functional group of Chemical Formula 7 below.

[0123] [Chemical Formula 7]

[0124]

[0125] In chemical formula 7, L7 and L8 are each independently a single bond, an alkylene group or an alkylidene group, and R 12 and R 13 are each independently hydrogen or the polar functional group, R 12 and R 13 One or more of the above may be a polar functional group.

[0126] The specific types of polar functional groups in chemical formulas 5 and 7 are as described above. The meaning of single bonds in chemical formula 7 and the specific types of alkylene groups and alkylidene groups are the same as in chemical formula 3.

[0127] For example, the ratio of the number of moles M4 of the monomer unit of the above chemical formula 4 to the number of moles M of the total monomer unit of the conductive polymer is 100×M4 / M, which is the ratio 100×M L / M can be adjusted within the same range.

[0128] For example, the ratio M4 / M5 of the mole number M4 of the monomer unit of the above chemical formula 4 to the mole number M5 of the monomer unit of the above chemical formula 5 in the conductive polymer can be adjusted within the same range as ML / MP.

[0129] In the conductive polymer, the lower limit of the ratio of the total mole number M4+M5 of the monomer units of the above chemical formulae 4 and 5 to the mole number M of the total monomer units included in the polymer, 100×(M4+M5) / M, may be about 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, or 95 mol%, and the upper limit may be about 100 mol%, 95 mol%, or 90 mol%. The ratio may be within a range that is equal to or greater than any lower limit selected from the lower limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above and equal to or greater than any lower limit selected from the lower limits listed above.

[0130] The conductive polymer may additionally contain other monomer units as long as they contain the aforementioned units in the above proportions.

[0131] The lower limit of the content of the conductive polymer within the polymer layer may be about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%, and the upper limit may be about 99%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40% or 35%. The ratio may be within a range that is equal to or greater than any lower limit selected from the lower limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above and equal to or greater than any lower limit selected from the lower limits listed above.

[0132] The polymer layer comprises the conductive polymer and can thus exhibit the above-described properties. As long as the polymer layer comprises the conductive polymer, it can also comprise any additional components.

[0133] For example, the polymer layer may additionally include a conductive material (conductive particle) along with the conductive polymer. By adding such a material, the oxidation potential of the polymer layer can be controlled, and excellent electrical characteristics can be secured. As the conductive material, a material having appropriate conductivity can be used. For example, the conductive material may be one or more selected from carbon particles, carbon fibers, graphene, graphite, carbon black, and carbon nanotubes.

[0134] As the above-mentioned conductive material (conductive particle), an appropriate type may be selected and used from among the types described above. There is no particular limitation on the shape of the conductive particle, and for example, it may have a spherical, irregular, plate-like, or fibrous shape, but is not limited thereto.

[0135] For proper effect, control of the size of the conductive material is necessary. For example, the lower limit of the average size of the conductive material (conductive particles) may be about 1 nm, 5 nm, 15 nm, 20 nm, 25 nm, or 30 nm, and the upper limit may be about 100 nm, 95 nm, 90 nm, 85 nm, 80 nm, 75 nm, 70 nm, 65 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm, or 30 nm. The average size may be within a range that is less than or equal to any upper limit selected from the upper limits listed above; or within a range that is less than or equal to any upper limit selected from the upper limits listed above and greater than or equal to any lower limit selected from the lower limits listed above. The average size of the conductive particles is measured by the method described in “8. Measurement of Average Particle Diameter of Conductive Particles” in the Examples section of the present specification. The closer the upper and lower limits of the average size of the challenge particles are to the average size of the challenge particles used in the examples (approximately 30 nm), the more effectively the desired effect can be achieved.

[0136] If the conductive material (conductive particle) is applied too large, it may inhibit the effect of the polymer layer (especially the PTC effect that causes an increase in resistance).

[0137] If necessary, the conductive material may be surface-treated to take into account dispersibility and coatability. In particular, such surface treatment can secure stable coatability and form a uniform polymer layer.

[0138] In this case, a surface treatment agent having appropriate compatibility with the conductive polymer can be used as a surface treatment agent. For example, the conductive material may be surface-treated with a polyphenol-based compound as a surface treatment agent. A polyphenol-based compound refers to a compound having a structure containing two or more linked hydroxyl groups substituted on benzene. Examples of such compounds include so-called catechol-based compounds (i.e., catechol or compounds containing the structure), and examples thereof include, but are not limited to, dopamine, polydopamine, 3,4-dihydroxy phenyl alanine, norephinephrine, tannic acid, humic acid, and / or lignin.

[0139] There is no limitation on the method for surface treating a conductive material with the above surface treating agent, and for example, a method of mixing the conductive material and the surface treating agent in an appropriate solvent, etc., or a method of synthesizing or polymerizing the surface treating agent on the surface of the conductive material can be applied.

[0140] The content of the conductive material can be adjusted in consideration of the desired oxidation potential. Generally, as the content of the conductive material in the polymer layer increases, the oxidation potential of the polymer layer decreases. Therefore, the content of the conductive material can be adjusted in consideration of the oxidation potential of the electrode active material and the corresponding oxidation potential of the polymer layer. For example, the lower limit of the content of the conductive material in the polymer layer relative to 100 parts by weight of the conductive polymer may be about 0.5 parts by weight, 1 part by weight, 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, and the upper limit may be about 150 parts by weight, 145 parts by weight, 140 parts by weight, 135 parts by weight, 130 parts by weight, 125 parts by weight, 120 parts by weight, 115 parts by weight, 110 parts by weight, 105 parts by weight, 100 parts by weight, 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 The content may be about 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, 10 parts by weight, 5 parts by weight, or 1 part by weight. The content may be within a range that is less than or equal to any upper limit selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit selected from the lower limits listed above; or within a range that is less than or equal to any upper limit selected from the upper limits listed above and greater than or equal to any lower limit selected from the lower limits listed above.

[0141] Under such a ratio, the conductive material can appropriately interact with the conductive polymer to effectively form a polymer layer of the desired shape.

[0142] The thickness of the polymer layer can be appropriately controlled depending on the purpose. For example, the lower limit of the thickness can be about 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, or 500 nm, and the upper limit can be about 2 μm, 1.5 μm, 1 μm, 950 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, 600 nm, 550 nm, 500 nm, 450 nm, 400 nm, 350 nm, or 300 nm. The thickness may range between being less than or equal to any upper limit selected from the upper limits listed above, being greater than or equal to any lower limit selected from the lower limits listed above, or being less than or equal to any upper limit selected from the upper limits listed above and being greater than or equal to any lower limit selected from the lower limits listed above.

[0143] The present application also relates to a method for manufacturing a current collector for the electrode. The manufacturing method includes a process for controlling the properties of the conductive polymer to achieve a desired PTC effect, etc.

[0144] The above manufacturing method may include a step of forming a polymer layer using a polymer solution containing the conductive polymer and, if necessary, the conductive material.

[0145] In the above step, the specific description of the conductive polymer and conductive material used is as described above, and the coating solution can be prepared by dissolving the polymer and / or conductive material in an appropriate solvent. At this time, the type of solvent is not particularly limited as long as it can dissolve at least a portion of the conductive polymer.

[0146] In the above step, the lower limit of the concentration of the conductive polymer present in the polymer solution may be about 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt% or 3 wt%, and the upper limit may be about 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 wt%. The ratio may be within a range that is equal to or greater than any lower limit selected from the lower limits listed above, or within a range that is equal to or less than any upper limit selected from the upper limits listed above, or within a range that is equal to or less than any upper limit selected from the upper limits listed above and equal to or greater than any lower limit selected from the lower limits listed above. This concentration may be changed as needed.

[0147] The above conductive polymer can be formed by a known polymerization method. For example, representative methods for producing polythiophene include a method utilizing an oxidative polymerization reaction or a method utilizing a radical reaction.

[0148] The polymer solution is used to form a polymer layer on a current collector. This process typically includes the steps of coating the polymer solution on the current collector and heat-treating the coated coating solution. In this specification, the polymer layer formed on the current collector prior to the heat treatment may be referred to as a precursor. The crystallinity of the conductive polymer and the orientation of the long-chain hydrocarbon functional groups can also be controlled by the conditions of the heat treatment.

[0149] For example, the heat treatment step may be performed in two stages. For example, the heat treatment step may include a first stage of first heat treating the precursor at a temperature T1; and a second stage of second heat treating the precursor at a temperature T2 following the first stage.

[0150] The conditions of the first and second steps can be adjusted to achieve the desired orientation or alignment of the functional groups of the conductive polymer and the dispersion state of the conductive material.

[0151] For example, the temperature T1 of the first heat treatment can be adjusted within a predetermined range. For example, the lower limit of the temperature range to which the temperature T1 belongs may be about 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, and the upper limit may be about 300°C, 290°C, 280°C, 270°C, 260°C, 250°C, 240°C, 230°C, 220°C, 210°C, 200°C, 190°C, 180°C, 170°C, 160°C, 150°C or 140°C. The temperature range may be within a range that is greater than or equal to any one of the lower limits listed above; or within a range that is greater than or equal to any one of the lower limits listed above and less than or equal to any one of the upper limits listed above.

[0152] In the above heat treatment step, the temperature T1 of the first heat treatment and the temperature T2 of the second heat treatment can be adjusted. For example, the lower limit of the ratio T1 / T2 of the temperature ranges T1 and T2 can be about 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 about 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. The ratio is within a range that is equal to or greater than any one lower limit selected from the above-listed lower limits; or within a range that is equal to or less than any one upper limit selected from the above-listed upper limits. Or it may be within a range that is equal to or greater than any one lower limit selected from the lower limits listed above, and equal to or less than any one upper limit selected from the upper limits listed above.

[0153] In one example, in the heat treatment step, the temperature T1 of the first heat treatment can be adjusted to be higher than the temperature T2 of the second heat treatment.

[0154] The ratio M2 / M1 of the heat treatment time M1 in the first heat treatment and the heat treatment time M2 in the second heat treatment can be additionally adjusted. For example, the lower limit of the ratio M2 / M1 may be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, and the upper limit may be about 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 is within a range that is greater than or equal to any one lower limit selected from the lower limits listed above; Or within a range that is less than or equal to any one of the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits listed above and less than or equal to any one of the upper limits listed above.

[0155] The lower limit of the above secondary heat treatment time M2 may be about 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours, 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours or 18 hours, and the upper limit may be about 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. It can be about 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 secondary heat treatment time M2 can be within a range that is equal to or greater than any lower limit selected from the lower limits listed above; or within a range that is equal to or less than any upper limit selected from the upper limits listed above; or within a range that is equal to or greater than any lower limit selected from the lower limits listed above and equal to or less than any upper limit selected from the upper limits listed above.

[0156] By the above heat treatment, the alignment state of the hydrocarbon functional groups of the conductive polymer is appropriately controlled, and accordingly, the desired effect can be obtained.

[0157] The method of coating the above coating solution is not particularly limited, and a known coating method can be applied.

[0158] In this application, a desired polymer layer and a current collector including the same are manufactured through the above process. The above process may include an appropriate post-processing step, if necessary.

[0159] The present application also relates to an electrode including the above-described collector.

[0160] As described above, the electrode may sequentially include the current collector body; a polymer layer and an active material layer.

[0161] The above polymer layer may be a polymer layer formed on the current collector body, specifically included in the aforementioned current collector. As described above, such a polymer layer can have a uniform and stable thickness through excellent coating properties.

[0162] A layer that is commonly applied can also be used as the above active material layer.

[0163] Typically, the above active material layer includes an electrode active material. There is no particular limitation on the specific type of the electrode active material, and typically, a material forming a positive or negative electrode can be used.

[0164] For example, when the active material layer is a positive electrode active material layer, the electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; or a compound having the chemical formula Li 1+c1 Mn 2-c1 Lithium manganese oxides such as O4(0≤c1≤0.33), LiMnO3, LiMn2O3, or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, or Cu2V2O7; chemical formula LiNi 1-c2 M c2 Ni-site type lithium nickel oxide represented by O2 (wherein, M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01≤c2≤0.3); chemical formula LiMn 2-c3 M c3Lithium manganese composite oxide represented by O2 (wherein, M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfies 0.01≤c3≤0.1) or Li2Mn3MO8 (wherein, M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); lithium nickel cobalt manganese (NCM) composite oxide, lithium nickel cobalt manganese aluminum (NCMA) composite oxide, and LiMn2O4 in which a part of Li in the chemical formula is replaced with an alkaline earth metal ion, but is not limited thereto.

[0165] When the above-mentioned active material layer is a negative electrode active material layer, a compound capable of reversible intercalation and deintercalation of lithium may be used as the electrode active material. Specific examples thereof include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, and Al alloys; metallic oxides capable of doping and dedoping lithium such as SiOa (0 < a < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the above-mentioned metallic compounds and carbonaceous materials such as Si-C composites or Sn-C composites, and any one or a mixture of two or more thereof may be used.

[0166] As the above negative active material, a lithium thin film may be used, and low-crystalline carbon and high-crystalline carbon may be used as carbon materials. Soft carbon and hard carbon are representative examples of low-crystalline carbon, and high-crystalline carbon is representative examples of amorphous, plate-like, flaky, spherical or fibrous natural or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, mesocarbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes.

[0167] The above electrode active material may be included in the active material layer in a range of about 80 wt% to 99.5 wt% or 88 wt% to 99 wt% relative to the total weight of the active material layer, but the ratio may be changed depending on the purpose or design of the electrode.

[0168] The above active material layer may additionally include a binder. The binder serves to improve adhesion between active materials and adhesive strength between the active material layer and the current collector body. Examples of the above binder are not particularly limited, and include, for example, PVDF (Poly(vinylidene fluoride)), PVA (poly(vinyl alcohol)), SBR (styrene butadiene rubber), PEO (poly(ethylene oxide)), CMC (carboxyl methyl cellulose), cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, cyanoethylpullulan, cyanoethyl polyvinylalcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, At least one selected from the group consisting of polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate may be used.

[0169] In one example, the binder may be included in the active material layer in an amount of 0.1 to 10 parts by weight or 0.5 to 5 parts by weight relative to 100 parts by weight of the electrode active material, but is not limited thereto.

[0170] The above active material layer may additionally include a conductive material, if necessary. As the conductive material, any known material may be used without particular limitation as long as it is conductive and does not cause chemical changes in the secondary battery. For example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, paneth black, lamp black, thermal black, etc.; conductive fibers such as carbon fiber or metal fiber; conductive tubes such as carbon nanotubes (CNTs); metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide, and / or conductive materials such as polyphenylene derivatives, etc. may be used.

[0171] The above-mentioned conductive material may be included in the active material layer in an amount of 0.1 to 20 parts by weight or 0.3 to 10 parts by weight relative to 100 parts by weight of the electrode active material, but is not limited thereto.

[0172] In addition to the components described above, the active material layer may additionally include any known components required.

[0173] The present application also relates to a method for manufacturing the above electrode.

[0174] The manufacturing method of the present application may include a step of forming the active material layer on the polymer layer on the current collector body.

[0175] There is no particular limitation on the method for forming the active material layer on the polymer layer. Typically, the active material layer is formed by coating a slurry containing the electrode active material, binder, and conductive agent on the current collector body (polymer layer), drying it, and then rolling it. This known method can be equally applied to the present application.

[0176] The present application also relates to an electrode assembly or electrochemical device including the above electrode, for example, a secondary battery.

[0177] The above-described electrochemical device may include the electrode as an anode and / or cathode. As long as the electrode of the present application is used as an anode and / or cathode, other configurations or manufacturing methods of the electrochemical device are not particularly limited, and known methods may be applied.

[0178] The present application relates to a current collector and its use. The present application provides a current collector and its use capable of forming an electrode that exhibits excellent electrical characteristics, including low resistance, under normal conditions, thereby not affecting the performance and operation of a secondary battery, and that, under abnormal conditions, blocks current flow through the electrode assembly through an increase in resistance, thereby ensuring stability.

[0179] Figure 1 is a cross-sectional view of an exemplary collector.

[0180] Figure 2 is a cross-sectional view of an exemplary electrode.

[0181] Figure 3 shows the NMR analysis results for the monomer of Manufacturing Example 1.

[0182] The contents of this application are specifically described through the following examples and comparative examples, but the scope of this application is not limited by the following examples.

[0183]

[0184] 1. NMR analysis method

[0185] 1 H-NMR analysis was performed at room temperature using a Bruker UltraShield spectrometer (300 MHz) equipped with a triple-resonance 5 mm probe. Samples were diluted in NMR solvent (CDCl3) to a concentration of approximately 10 mg / ml, and chemical shifts were expressed in ppm.

[0186]

[0187] 2. GPC (Gel Permeation Chromatograph)

[0188] Molecular weight characteristics were measured using gel permeation chromatography (GPC). 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. The analysis program used Waters' Empower 3, and the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were obtained by comparing the elution time of the sample with the calibration curve, and the molecular weight distribution (PDI) was calculated as the ratio (Mw / Mn).

[0189] The measurement conditions of GPC are as follows.

[0190] <GPC 측정 조건>

[0191] Device: Waters 2414

[0192] Column: Using 3 Styragel from Waters

[0193] Solvent: THF (Tetrahydrofuran)

[0194] Column temperature: 35℃

[0195] Sample concentration: 1 mg / mL, 1 μL injection

[0196] Standard samples: polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

[0197]

[0198] 3. Thickness measurement

[0199] The thickness of the polymer layer, etc., was measured by taking a SEM (Scanning Electron Microscope) (JEOL, JSM-7200F) image after cross-section processing using an ion milling device (Hitachi, IM5000). The conditions for cross-section formation by the ion milling were as follows: the device was set to cross-section milling mode, the speed (reciprocation / min) was 3, the acceleration voltage was 6.0 kV, the discharge voltage was 15 kV, the current was 150 μA, and the time was 4 hours.

[0200]

[0201] 4. Oxidation potential measurement method

[0202] The oxidation potential was measured in the following manner. A polymer layer was formed to a thickness of approximately 10 μm on aluminum foil (Al Foil) having a thickness of approximately 15 μm using a conductive polymer. The polymer layer was formed in the same manner as described in each example or comparative example, 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 in which aluminum foil / polymer layer / separator / lithium film were laminated, and the laminate was punched into a circle with a diameter of approximately 1.4 cm. A coin cell was manufactured using the laminate punched into a circle and the electrolyte (using the Welcos CR2032 coin cell kit). As the above separator, the WL20C model of W-Scope Korea was used, and as the lithium film, a lithium film with a thickness of approximately 100 μm was used, and as the electrolyte, a product of Enchem (1M LiPF6 solution (solvent: EC / DMC / EMC=3 / 4 / 3 (mass ratio), EC: Ethylene Carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate)) was used.

[0203] The oxidation potential of the above coin cell was measured at 25°C using a potentiostat (Princeton Applied Research, PARASTAT-MC). The oxidation potential was measured by measuring CV (Cyclic Voltammetry) at a scan rate of 0.17 mV / sec to 0.5 mV / sec in the range of 1.5 V to 5.5 V.

[0204]

[0205] 5. AC impedance resistance measurement

[0206] The AC impedance resistance was evaluated through EIS (Electrochemical Impedance Spectronization) using the same coin cell used in the oxidation potential measurement (however, in this case, the thickness of the polymer layer was the same as in each example and comparative example). A voltage of 4.3 V was applied to the coin cell at room temperature (25°C) for 10 minutes, and a Nyquist plot was obtained by EIS measurement from 50,000 Hz to 0.1 Hz, and the AC impedance resistance obtained in the high frequency region (R in Equation 1) 25 ) was measured. An electrochemical measuring instrument (potentiostat) (Princeton Applied Research, PARASTAT-MC) was used for EIS measurement.

[0207] AC impedance resistance at 130℃ (R in Equation 1) 130) was evaluated in the following manner. The coin cell was placed in the center of a convection oven (Jeotech, OF3-05W), the oven temperature was set to 130°C, and the AC impedance resistance was measured. The resistance was measured by connecting the coin cell to a multimeter for measuring resistance outside the oven (Fluke's digital multi-tester (FLUKE-87-5)). Before placing the coin cell, the oven temperature was set to 130°C, and when the temperature inside the oven stabilized, the coin cell was placed and maintained at the temperature for about 10 minutes, and then the AC impedance resistance R 130 was measured.

[0208]

[0209] 6. 2C discharge efficiency and 30 cycle life measurement

[0210] Coin cells (standard capacity: 200 mAh / g) were manufactured using a CR2032 standard coin cell kit (Welcos CR2032 coin cell kit). The electrodes manufactured in the examples or comparative examples were used as the positive electrode, and a lithium film (thickness: 100 μm) was used as the negative electrode. As the electrolyte, a 1 M LiPF6 solution (solvent: EC / DMC / EMC=3 / 4 / 3 (mass ratio), EC: Ethylene Carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate) was used as a carbonate-based electrolyte, and a PE (poly(ethylene)) separator (WL20C model, W-Scope Korea) was used as the separator. The 2C discharge efficiency and 30 cycle lifespan were evaluated for the coin cells.

[0211] The above 2C discharge efficiency is a value obtained by substituting the discharge capacities A and B into the equation 100×B / A after measuring the discharge capacity A while charging the coin cell at a rate of 0.5C using the CC (Constant Current) / CV (Constant Voltage) method with a charge end voltage of 4.5 V and a charge end current of 1 mA, and discharging at a rate of 0.1C using the CC (Constant Current) method with a discharge end voltage of 3.0 V, and after measuring the discharge capacity B while charging the coin cell at a rate of 0.5C using the CC (Constant Current) / CV (Constant Voltage) method with a charge end voltage of 4.5 V and a charge end current of 1 mA, and discharging at a rate of 2C using the CC (Constant Current) method.

[0212] In addition, the 30-cycle lifespan above was obtained by performing 30 charge / discharge cycles (30 cycles) at 45°C for the coin cell. Specifically, the charge end voltage is set to 4.5 V and the charge end current is set to 1 mA, and the process of charging at a rate of 0.2 C using the CC (Constant Current) / CV (Constant Voltage) method, and the discharge end voltage is set to 3.0 V and the discharge is performed at a rate of 0.2 C using the CC (Constant Current) method, and the above cycle is repeated 30 times, which is one cycle. Then, the discharge capacity C1 measured after performing the first cycle and the discharge capacity C30 after performing the 30th cycle are substituted into the equation 100×C30 / C1 to obtain the 30-cycle lifespan.

[0213]

[0214] 7. Measurement of room temperature and high temperature discharge capacity

[0215] Coin cells (standard capacity: 200 mAh / g) were manufactured using a coin cell kit (Welcos CR2032 coin cell kit) of CR2032 standard. The electrodes manufactured in the examples or comparative examples were used as the positive electrode, and a lithium film (thickness: 100 μm) was used as the negative electrode. As the electrolyte, a 1M LiPF6 solution (solvent: EC / DMC / EMC=3 / 4 / 3 (mass ratio), EC: Ethylene Carbonate, DMC: dimethyl carbonate, EMC: ethylmethyl carbonate) was used as a carbonate-based electrolyte, and a PE (poly(ethylene)) separator (WL20C model from W-Scope Korea) was used as the separator. The coin cells were charged / discharged once at 25°C, and the capacity at 0.2C was expressed as the discharge capacity at 25°C (C in Equation 2). 25 ) was performed. One charge / discharge cycle is performed by charging at a rate of 0.2C in the CC (Constant Current) / CV (Constant Voltage) method with a charge end voltage of 4.5V and a charge end current of 1mA, and discharging at a rate of 0.2C in the CC (Constant Current) method with a discharge end voltage of 3.0V, and repeating the process once. The discharge capacity after one charge / discharge cycle is the discharge capacity at 25℃ (C in Equation 2). 25 ) was used.

[0216] Separately, the discharge capacity at 130℃ (C in Equation 2) 130 ) was measured. The discharge capacity C 25 In the process of measuring the discharge capacity C, the coin cell was charged at a rate of 0.2C using the CC (Constant Current) / CV (Constant Voltage) method, with the charging end voltage set to 4.5V and the charging end current set to 1mA, and then stored at 130℃ for 10 minutes. 130 The discharge capacity C was measured. 130The results were measured by discharging a coin cell stored at 130°C for 10 minutes after charging at a discharge end voltage of 3.0 V in a CC (Constant Current) manner at a rate of 1C. The discharge was performed at 130°C.

[0217]

[0218] 8. Measurement of average particle diameter of challenge particles

[0219] The average particle diameter (D50 particle diameter) of the conductive particles was measured using a MASTERSIZER3000 from Marvern in accordance with the ISO-13320 standard. Toluene was used as the solvent during the measurement. When the sample (conductive particles) was dispersed in the solvent and a laser was irradiated, the laser was scattered by the sample dispersed in the solvent. Since the intensity and directionality of the scattered laser vary depending on the size of the particles, this can be analyzed using Mie theory to obtain the average particle diameter. Through the above analysis, the measurement results were converted into the particle diameter of a sphere having the same volume as the dispersed sample to obtain a volume-based cumulative graph of the particle size distribution, and the particle diameter at 50% of the cumulative point of the graph (median particle diameter) was designated as the average particle diameter (D50 particle diameter).

[0220]

[0221] Manufacturing Example 1. Synthesis of monomer (A)

[0222] The monomer of the following chemical formula A was synthesized in the following manner.

[0223] [Chemical Formula A]

[0224]

[0225] 3-Methoxythiophene 3 g (26.28 mmol, 1 eq) and triethylene glycol monomethyl ether 7.03 g (39.42 mmol, 1.5 eq) were dissolved in 150 ml of toluene 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, and the methanol produced by the reaction (transetherification) was removed with a 4A type molecular sieve packed in a soxhlet extractor. After refluxing for 24 h, the reaction 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 using methylene chloride / hexane (2:1) elution to obtain the target compound (monomer (A)). The NMR analysis results for the monomer (A) are shown in Figure 3.

[0226]

[0227] Manufacturing Example 2. Synthesis of polythiophene (B)

[0228] 3-dodecylthiophene 1 g (3.94 mmol, 0.6 eq), 3-hexylthiophene 0.33 g (1.97 mmol, 0.3 eq) and monomer (A) of Preparation Example 1 0.16 g (0.66 mmol, 0.1 eq) were added to a solution of 3.20 g (19.71 mmol, 3 eq) of iron (III) chloride dissolved in 150 ml of methylene chloride, and polymerized at 30°C for 24 hours to produce polythiophene (A). The polymerization solution was placed in an osmotic membrane with a molecular weight cut-off (MWCO) of 5000 and immersed in 200 ml of acetonitrile to remove unreacted iron (III) chloride, monomers, and low-molecular-weight oligomers. The residue precipitated inside the osmotic membrane was washed with methanol and dried at 60°C for 12 hours to produce polythiophene (A). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polythiophene (A) were approximately 118,000 g / mol and 24,500 g / mol, respectively.

[0229]

[0230] Manufacturing Example 3. Polydopamine-coated conductive particles (A)

[0231] As challenging particles, carbon black particles (IMERYS, C-NERGY TMSUPER C65) was used. The average particle diameter (D50 particle diameter) of the conductive particles was approximately 30 nm. Dopamine hydrochloride (CAS No. 62-31-7) was added to a buffer solution and stirred at room temperature (approximately 25°C). The buffer solution used was a 0.1M pH 8.5 Tris-buffer product from Biosesang Co., Ltd. The molar concentration of DHC in the final solution was approximately 2 mg / mL. The conductive particles were dispersed (sonicated for 1 hour) in a mixture of the buffer solution and DHC at a concentration of approximately 4 mg / mL and further stirred for approximately 18 hours to form a coating layer of polydopamine on the conductive particles. After filtering under reduced pressure using a paper filter, the conductive particles were vacuum-dried to obtain conductive particles coated with polydopamine.

[0232]

[0233] Manufacturing Example 4. Polydopamine-coated conductive particles (B)

[0234] Polydopamine-coated conductive particles were obtained in the same manner as in Manufacturing Example 3, except that carbon black particles (Aldrich, Carbon nanopowder) having an average particle diameter (D50 particle diameter) of approximately 100 nm were used as the conductive particles.

[0235]

[0236] Example 1.

[0237] Polythiophene (B) of Manufacturing Example 2 and conductive particles (A) of Manufacturing Example 3 were mixed in a weight ratio of 80:20 (polythiophene:conductive particles), and the mixture was dispersed in a solvent (chloroform) at a concentration of about 2 wt% to prepare a coating solution. The coating solution was coated on a current collector body by bar coating, and heat-treated (dried) at 140°C for about 4 minutes and then heat-treated (annealed) at 130°C for about 1 hour to form a polymer layer having a thickness of about 500 nm. As the current collector body, an Al foil having a thickness of about 15 μm was used. Subsequently, an active material layer was formed on the polymer layer. The active material layer was formed by applying a slurry containing lithium cobalt oxide (LiCoO2), carbon-based conductive material (ECP (Ketjen Black) 0.5%, SFG (Trimrex graphite) 0.4%, DB (Denka Black) 0.4%), PVDF (polyvinylidene fluoride), and NMP (N-Methyl-2-pyrrolidone) in a weight ratio of 75:1:1:23 (LiCoO2:conductive material:PVDF:NMP) using a doctor blade to a thickness of about 90 μm on the polymer layer, drying at room temperature (about 25°C), and then further drying under vacuum conditions at 120°C. Subsequently, the slurry was rolled to have a porosity of about 25% to manufacture an electrode.

[0238]

[0239] Example 2.

[0240] A current collector and electrode were manufactured in the same manner as in Example 1, except that a coating solution was used by mixing the polythiophene (B) of Manufacturing Example 2 and the conductive particles (A) of Manufacturing Example 3 in a weight ratio of 70:30 (polythiophene:conductive particles) when forming the polymer layer, and dispersing the mixture in a solvent (chloroform) at a concentration of about 2 wt%.

[0241]

[0242] Example 3.

[0243] A current collector and electrode were manufactured in the same manner as in Example 1, except that a coating solution was used by mixing the polythiophene (B) of Manufacturing Example 2 and the conductive particles (A) of Manufacturing Example 3 in a weight ratio of 60:40 (polythiophene:conductive particles) when forming the polymer layer, and dispersing the mixture in a solvent (chloroform) at a concentration of about 2 wt%.

[0244]

[0245] Comparative Example 1.

[0246] A current collector and electrode were manufactured in the same manner as in Example 1, except that a coating solution prepared by dispersing only polythiophene (B) of Manufacturing Example 2 in a solvent (chloroform) at a concentration of about 2 wt% was used when forming the polymer layer.

[0247]

[0248] Comparative Example 2.

[0249] A current collector and electrode were manufactured in the same manner as in Example 1, except that a coating solution was used by mixing the polythiophene (B) of Manufacturing Example 2 and the conductive particles (A) of Manufacturing Example 3 in a weight ratio of 40:60 (polythiophene:conductive particles) when forming the polymer layer, and dispersing the mixture in a solvent (chloroform) at a concentration of about 2 wt%.

[0250]

[0251] Comparative Example 3.

[0252] A current collector and electrode were manufactured in the same manner as in Example 3, except that the conductive particles (B) of Manufacturing Example 4 were used instead of the conductive particles (A) of Manufacturing Example 3.

[0253]

[0254] Comparative Example 4.

[0255] An electrode was manufactured by forming an active material layer directly on the current collector body without forming a polymer layer.

[0256]

[0257] The measurement results for the polymer layer, current collector, or electrode of the above-mentioned manufactured examples and comparative examples are summarized in Tables 1 and 2 below. In Tables 1 and 2 below, the 25C resistance is the AC impedance resistance (R25 in Equation 1)(Ω) at room temperature (25°C) measured according to the AC impedance resistance measurement method, and the 130C resistance is the AC impedance resistance (R130 in Equation 1)(Ω) at 130°C measured according to the AC impedance resistance measurement method.

[0258] In addition, the 25C discharge capacity in Tables 1 and 2 below is the discharge capacity at 25°C measured according to the above room temperature and high temperature discharge capacity measurement methods (C in Equation 2). 25 ), and the 130C discharge capacity is the discharge capacity at 130°C measured according to the above room temperature and high temperature discharge capacity measurement method (C in Equation 2). 130 )am.

[0259] Example 1232C Discharge Efficiency 80.881.782.530 Cycle Life 95.297.899.125C Resistance 10.58.67.7130C Resistance 250200174 △R(%) of Equation 1 22812226216025C Discharge Capacity 187.8189.2190.3130C Discharge Capacity 25.635.240.3 △C(%) of Equation 2 86.481.478.8

[0260] Comparative Example 12342C Discharge Efficiency 65.490809030 Cycle Life 73.499859925C Resistance 405.38.21.7130C Resistance 31013.217.31.8 △R(%) of Formula 1 6751491115.825C Discharge Capacity 187.0190.7189.0192.1130C Discharge Capacity 21.2164.5157.8158.4 △C(%) of Formula 2 88.713.716.517.5

[0261]

[0262] Through the results in Tables 1 and 2, it can be confirmed that the electrode according to the present application exhibits a low resistance in a normal state, so as not to affect the performance and operation of the secondary battery, and exhibits a characteristic that can secure stability by blocking the current flow of the electrode assembly through an increase in resistance in an abnormal state caused by overcharging, exposure to high temperatures, or external impact.

Claims

1. The entire body of the house; and Including a polymer layer formed on one or both sides of the above-mentioned main body, The above polymer layer includes a conductive polymer and conductive particles, The AC impedance resistance at 25℃ is less than 40 Ω, A current collector having △R of 200% or more according to the following equation 1: [Formula 1] △R = 100 × (R 130 - R 25 ) / R 25 R in Equation 1 25 is the AC impedance resistance at 25℃, and R 130 is the AC impedance resistance at 130℃.

2. In the first paragraph, a current collector in which the absolute value of △C in the following equation 2 is 20% or more: [Formula 2] △C = 100 × (C 25 -C 130 ) / C 25 C in Equation 2 25 is the discharge capacity at 25℃, and C 130 is the discharge capacity after 10 minutes of storage at 130℃.

3. In the first paragraph, the conductive polymer is a current collector having a long-chain hydrocarbon functional group.

4. In the third paragraph, the conductive polymer is a current collector including a first hydrocarbon functional group having 10 or more carbon atoms and a second hydrocarbon functional group having 9 or less carbon atoms as long-chain hydrocarbon functional groups.

5. A current collector in which, in the fourth paragraph, the total molar ratio of the monomer unit having the first hydrocarbon functional group and the monomer unit having the second hydrocarbon functional group in the conductive polymer is 70 mol% or more.

6. A current collector in the fifth paragraph, wherein the ratio M2 / M1 of the number of moles M2 of monomer units having a second hydrocarbon functional group to the number of moles M1 of monomer units having a first hydrocarbon functional group is within a range of 0.01 to 100.

7. In the third paragraph, the conductive polymer is a current collector having an additional polar functional group.

8. In the 7th paragraph, the polar functional group is a carboxyl group, a hydroxyl group, an amino group, a cyano group, a nitro group, an ether group or a functional group of the following chemical formula 3: [Chemical Formula 3] In chemical formula 3, L4 is a single bond, an alkylene group, or an alkylidene group, L3 is an alkylene group or an alkylidene group, R5 is hydrogen or an alkyl group, and n is a number in the range of 1 to 10.

9. In paragraph 7, the number of moles M of monomer units having a long-chain hydrocarbon functional group in the conductive polymer L The number of moles M of monomer units having polar functional groups P Ratio for M L / M P Electrodes having a range of 1 to 500.

10. A current collector for an electrode in the first paragraph, wherein the conductive particles are carbon particles, carbon fibers, graphene, graphite, carbon black or carbon nanotubes.

11. A current collector in the first paragraph, wherein the average size of the challenge particles is less than 100 nm.

12. A current collector in which the content of the conductive polymer in the polymer layer is in the range of 40 to 99 wt% in the first paragraph.

13. A current collector comprising 1 to 145 parts by weight of conductive particles relative to 100 parts by weight of the conductive polymer in the 12th paragraph.

14. The entire body of any one of paragraphs 1 to 13; and An electrode comprising an active material layer formed on a polymer layer of the above-mentioned collector.

15. In the 14th paragraph, the active material layer is an electrode including a positive electrode active material.

16. An electrode assembly comprising the electrode of clause 14.

17. A secondary battery comprising the electrode of clause 14.

18. A secondary battery comprising the electrode assembly of clause 16.

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