Electrode for secondary battery including electroconductive flame retardant layer and secondary battery including same

Abstract

An electrode for a secondary battery comprising an electronically conductive flame-retardant layer is provided. The electrode comprises a current collector, an active material layer, and an electronically conductive flame-retardant layer provided between the current collector and the active material layer, wherein the electronically conductive flame-retardant layer comprises a conductive material, a flame retardant, and a polymer binder, and wherein the flame retardant is encapsulated inside the polymer binder.

Description

Technology Field

[0001] The present invention relates to an electrode for a secondary battery comprising an electronically conductive flame-retardant layer and a secondary battery comprising the same. Background Technology

[0002] With the recent rapid growth of the electric vehicle market, the importance of lithium-ion rechargeable batteries, a key component, is increasing day by day. Lithium-ion rechargeable batteries possess high energy density and excellent charge / discharge characteristics; due to these properties, they are being used as a core power source across various industries, including not only medium and large-sized batteries for electric vehicles and Energy Storage Systems (ESS), but also small portable electronic devices such as mobile phones and laptops.

[0003] In particular, the development of next-generation high-energy-density lithium-ion batteries is accelerating, and attempts to increase volume and energy density per unit volume, such as in lithium-sulfur batteries and lithium-air batteries, are continuing.

[0004] These secondary batteries are sensitive to external forces and temperatures, posing a risk of accidents such as explosions and posing a safety vulnerability. Therefore, there is a need for measures to further maximize the safety of secondary batteries. Prior art literature

[0005] Published Patent Application No. 10-2015-0014895 (February 9, 2015) The problem to be solved

[0006] The problem to be solved by the present invention is to provide an electrode for a secondary battery comprising an electronically conductive flame-retardant layer and a secondary battery comprising the same, which is manufactured by coating and inserting the electronically conductive flame-retardant layer between a current collector and an active material layer to improve the ignition stability of a liquid electrolyte-based secondary battery.

[0007] However, the problems that the present invention aims to solve are not limited to those described above, and other problems may exist. means of solving the problem

[0008] An electrode for a secondary battery comprising an electronically conductive flame-retardant layer according to an embodiment of the present invention for solving the above-mentioned problem comprises a current collector, an active material layer, and an electronically conductive flame-retardant layer provided between the current collector and the active material layer, wherein the electronically conductive flame-retardant layer comprises a conductive material, a flame retardant, and a polymer binder, and the flame retardant is encapsulated inside the polymer binder.

[0009] In some embodiments of the present invention, the electronically conductive flame retardant layer is formed by mixing a conductive material, a flame retardant, and a polymer binder, coating the mixture, and then drying it, wherein the flame retardant exposed on the surface of the polymer binder can be removed through a washing process using a washing solvent.

[0010] In some embodiments of the present invention, the materials constituting the polymer binder and the flame retardant are selected based on the difference in solubility of the electrolyte, the slurry solvent, and the washing solvent, and the slurry solvent may be a solvent capable of dissolving both the polymer binder and the flame retardant.

[0011] In some embodiments of the present invention, the washing solvent may be a solvent capable of dissolving only the flame retardant without dissolving the polymer binder.

[0012] In some embodiments of the present invention, the coating of the electronically conductive flame-retardant layer may be performed based on at least one of dip coating, rod coating, knife coating, blade coating, roll coating, gravure coating, and slot coating, which are capable of large-area wet coating.

[0013] In some embodiments of the present invention, the conductive material may include at least one of carbon black, acetylene black, ketjen black, carbon nanotubes, and graphene.

[0014] In some embodiments of the present invention, the flame retardant may include at least one of trimethyl phosphate (TMP), triphenyl phosphate (TPP), bis(2-methoxyethoxy)methylallylphosphonate, tris(2,2,2-trifluoroethyl)phosphite, (ethoxy)pentafluorocyclotriphosphazene, ethylene ethyl phosphate, and Tis(2-chloroethyl phosphate).

[0015] In some embodiments of the present invention, the polymer binder may comprise at least one of paraffin, polyethylene oxide, styrene butadiene rubber, nitrile butadiene rubber, polyethylene, polytetrafluoroethylene, and polyvinylidene fluoride.

[0016] In some embodiments of the present invention, the electronically conductive flame retardant layer may be formed by coating to have a thickness of 10 to 70 μm, taking into account electrical conductivity.

[0017] Other specific details of the present invention are included in the detailed description and drawings. Effects of the invention

[0018] According to one embodiment of the present invention described above, the ignition stability of a secondary battery can be improved by coating a flame-retardant inner layer on the top of a current collector and manufacturing an electrode including the same.

[0019] In addition, by preparing a slurry using the difference in solubility between the polymer binder and the flame retardant depending on the solvent, it is possible to manufacture flame-retardant layers with various material combinations, and there is an advantage that flame retardancy can be achieved by encapsulating the flame retardant through a large-area process without degrading cell characteristics.

[0020] That is, by applying an anode or cathode slurry on top of an electronically conductive flame-retardant layer, it can be utilized as an anode or cathode plate of a secondary battery, and finally combined with a separator and an electrolyte to form a secondary battery, thereby providing a secondary battery that stably maintains cell characteristics within a current density while effectively exhibiting extinguishing ability in a fire environment.

[0021] In addition, the process in the present invention is performed based on a slurry-based thick film process capable of large-area implementation, which enables high efficiency and reduced process costs.

[0022] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below. Brief explanation of the drawing

[0023] FIG. 1 is a drawing for explaining the selection of materials considering the difference in solubility of the present invention. FIG. 2 is a drawing illustrating an electrode for a secondary battery according to one embodiment of the present invention. Figure 3 is a diagram showing the SEM analysis results of an electrode for a secondary battery including an electronically conductive flame-retardant layer. Figure 4 shows the results of measuring and comparing self-extinguishing time depending on the presence or absence of an electronically conductive flame-retardant layer in the electrode. Figure 5 is a diagram illustrating the results of cell characteristic analysis based on the presence or absence of an electronically conductive flame-retardant layer within the electrode. Specific details for implementing the invention

[0024] Embodiments of the present invention are described below with reference to the attached drawings to enable those skilled in the art to easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0025] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" with other elements interposed between them.

[0026] Throughout this specification, when a component is described as being located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0027] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Throughout this specification, terms of degree such as "about," "substantially," etc., are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the said meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding this specification. Throughout this specification, terms of degree such as "step of" or "step of" do not mean "step for."

[0028] The present invention relates to an electrode for a secondary battery comprising an electronically conductive flame-retardant layer and a secondary battery comprising the same.

[0029] In recent years, fire accidents involving electric vehicles and ESS have surged, and with the occurrence of fire accidents involving mobile phones, battery safety is also receiving significant attention. Generally, organic solvent-based liquid electrolytes are highly volatile and have low ignition points, making them highly sensitive to external forces and temperatures as they ignite easily.

[0030] In particular, abnormal high temperature phenomena such as internal circuit short circuits, overcharging, overheating, and external impacts caused by unstable operation of secondary batteries and improper management systems are considered to be the main causes of battery ignition. Furthermore, since a fire that starts in one cell can spread uncontrollably to adjacent cells, leading to large-scale ignition and explosion, secondary batteries can be considered very vulnerable in terms of safety.

[0031] To address these problems, efforts have been made to control the internal and external ignition factors of secondary electrons.

[0032] First, there is a method of applying electronic devices such as temperature and pressure sensors to control external ignition factors. However, this method increases the volume and weight of the entire secondary battery system, thereby offsetting the high energy density characteristics that are an advantage of secondary batteries.

[0033] For this reason, incorporating an ignition suppression system within the secondary battery without significantly increasing its volume and density is considered a solution. One highly efficient method involves mixing flame-retardant additives into the electrolyte. However, while the application of flame-retardant additives demonstrates high efficiency in suppressing cell ignition, there is a problem in that increasing the amount of the additive in the electrolyte deteriorates ion conductivity, leading to a rapid degradation of the secondary battery's performance.

[0034] Therefore, there is a need for an internal ignition suppression method in which flame-retardant properties are exhibited only during abnormal high-temperature phenomena, without the direct addition of flame-retardant additives to the electrolyte.

[0035] To this end, one embodiment of the present invention manufactures an electrode by coating and inserting an electron-conducting flame-retardant layer between a current collector and an active material layer within both electrodes of a secondary battery, and is characterized by encapsulating a flame-retardant additive inside a polymer film through large-area encapsulation technology to prevent the flame-retardant from dissolving directly into the electrolyte, while simultaneously adding a conductive material to enable effective electron transfer to the active material layer.

[0036] Through this, one embodiment of the present invention can not only resolve the thermal runaway phenomenon that occurs in conventional lithium-ion secondary batteries, where the flame retardant in the flame retardant layer leaches out when the secondary battery manufactured with the electrode having the above flame retardant layer operates at a high temperature or higher, but also resolve the problem of cell characteristic degradation caused by the flame retardant applied directly as an additive to the electrolyte.

[0037] Hereinafter, with reference to FIGS. 1 and 2, an electrode (1) for a secondary battery including an electronically conductive flame-retardant layer according to one embodiment of the present invention will be described.

[0038] FIG. 1 is a drawing for explaining the selection of materials considering the difference in solubility of the present invention. FIG. 2 is a drawing illustrating an electrode (1) for a secondary battery according to one embodiment of the present invention.

[0039] An electrode (1) for a secondary battery including an electronically conductive flame-retardant layer according to one embodiment of the present invention comprises an active material layer (100), an electronically conductive flame-retardant layer (200), and a current collector (300). At this time, the electronically conductive flame-retardant layer (200) is provided between the current collector (300) and the active material layer (100).

[0040] The electronically conductive flame retardant layer (200) comprises a conductive material, a flame retardant, and a polymer binder.

[0041] The electronically conductive flame-retardant layer (200) is formed by mixing a conductive material, a flame retardant, and a polymer binder, coating the mixture, and then drying it. After this process, the flame retardant and the conductive material exist in a composite form inside and outside the polymer binder, which accounts for the largest weight ratio.

[0042] In one embodiment, it is preferable that the conductive material be selected as a material capable of achieving high electrical conductivity with a minimum content. Carbon materials having mainly low density may be used as the conductive material, and representative examples may include at least one of carbon black, acetylene black, ketjen black, carbon nanotubes, and graphene.

[0043] Generally, the electrical conductivity of the finished invention increases linearly as the content of the conductive material increases. However, since the content of the internal flame retardant decreases as the content of the conductive material increases within the same volume, optimization of the appropriate content is required. Furthermore, in the case of carbon materials with a high aspect ratio, high electronic conductivity can be achieved with a small amount, so the use of carbon materials with a high aspect ratio may be more ideal.

[0044] The flame retardant is selected as a material capable of having a fire suppression function within the electrolyte. In one embodiment, the flame retardant is mainly manufactured using organic phosphorus compounds and organic halogenated compounds, and may be composed of at least one of, for example, trimethyl phosphate (TMP), triphenyl phosphate (TPP), bis(2-methoxyethoxy)methylallylphosphonate, tris(2,2,2-trifluoroethyl)phosphite, (ethoxy)pentafluorocyclotriphosphazene, ethylene ethyl phosphate, and Tis(2-chloroethyl phosphate).

[0045] As described below, when the secondary battery exceeds a high temperature, the flame retardant compound present within the polymer binder generates phosphorus-containing free radicals that engulf hydrogen (H) and hydroxyl (OH) radicals that induce ignition, thereby causing self-extinguishment.

[0046] In other words, the flame retardant exists encapsulated within the polymer binder. The flame retardant encapsulated within the polymer binder exists without being exposed to the electrolyte.

[0047] On the other hand, flame retardants exposed on the surface of the polymer binder form part of the secondary battery along with the electrolyte and may leach out into the electrolyte. Since the electrolyte mixed with the leached flame retardant reduces ionic conductivity and degrades electrochemical properties, a process is required to selectively remove only the flame retardant exposed on the surface.

[0048] To this end, one embodiment of the present invention is characterized by removing a flame retardant exposed on the surface of a polymer binder through a washing process using a washing solvent. The flame retardant is composed of a material that is soluble in both the slurry solvent and the washing solvent.

[0049] In one embodiment, the washing solvent is characterized as a solvent that does not dissolve the polymer binder and can only dissolve the flame retardant. That is, in one embodiment of the present invention, the flame retardant and the polymer binder include an electrolyte, a slurry solvent, and an exposed flame retardant washing solvent, and a composite polymer thin film can be manufactured by selecting materials that take into account the difference in solubility for each solvent.

[0050] The polymer binder is composed of a material that is electrochemically stable within the driving voltage, does not dissolve in the electrolyte and washing solvent, and dissolves in the slurry solvent.

[0051] In one embodiment, the polymer binder may be composed of at least one of paraffin, polyethylene oxide, styrene butadiene rubber, nitrile butadiene rubber, polyethylene, polytetrafluoroethylene, and polyvinylidene fluoride.

[0052] Meanwhile, at least one of toluene, xylene, acetone, methanol, ethanol, n-methyl-2-pyrrolidone, and dimethylformamide may be selected and used as a solvent for the wet slurry process.

[0053] Among the above solvents, a solvent capable of dissolving both the polymer binder and the flame retardant is used as a slurry solvent, and a solvent capable of dissolving only the flame retardant without dissolving the polymer binder is used as a washing solvent, thereby manufacturing a flame-retardant inner layer through an appropriate combination of the polymer binder, flame retardant, and solvent.

[0054] A wet slurry mixture prepared according to one embodiment of the present invention is coated using a large-area coating method with a thickness between 1 and 100 μm, taking into account cell characteristics and electrical conductivity. Generally, when a thick film is formed, it contains a large amount of flame retardant, resulting in excellent flame retardancy, but conversely, it is disadvantageous in terms of electron conductivity and energy density. In addition, if it is excessively thin, it may be advantageous in terms of electron conductivity and energy, but sufficient flame retardancy may not be imparted. Considering these points, it is preferable that the electron-conducting flame-retardant layer (200) in one embodiment of the present invention be formed by coating with a thickness of 10 to 70 μm, taking into account electrical conductivity.

[0055] In one embodiment of the present invention, a large-area thin film coating method for an electronically conductive flame-retardant layer (200) that can be used may be applied using one or more of dip coating, rod coating, knife coating, blade coating, roll coating, gravure coating, and slot coating, which are capable of large-area wet coating. After coating, the material is manufactured by vacuum drying at an appropriate temperature, taking into account the characteristics of the materials used.

[0056] On the surface of the thin film manufactured by the above method, a flame retardant is present that is not encapsulated within the polymer binder and remains exposed, which may subsequently dissolve into the electrolyte and drastically reduce cell characteristics. As described above, in one embodiment of the present invention, a washing process using a washing solvent is performed to remove the exposed flame retardant, thereby allowing the flame retardant to be encapsulated only within the polymer matrix. This process may be selected and applied either before or after the active material layer of the anode or cathode is applied.

[0057] Once the electronically conductive flame-retardant layer (200) is formed, an active material layer (100) is laminated on top of the electronically conductive flame-retardant layer (200) and can be used as a positive or negative electrode plate. At this time, as the positive active material, sulfur, LiCoO2, LiNiO2, and LiNi x Co y Mn z One or more of O2(x+y+z=1), LiMn2O4, LiFePO4, etc. may be used in combination, and as the negative electrode active material, silicon, tin, graphite, lithium, etc. may be used alone or in combination.

[0058] It is common to include a polymeric binder and a conductive material to ensure mechanical bonding strength and electrical conductivity of the two electrodes. Regarding the polymeric binder, it is preferable to select and use a polymer-solvent system among the aforementioned polymers that does not affect the underlying layer. Generally, it is appropriate to select a solvent system that does not dissolve the polymer used in the underlying layer. As for the conductive material, at least one can be selected from carbon black, carbon nanotubes, graphene, etc.

[0059] Meanwhile, the ratio of active material, polymer binder, and conductive material in the electrode can be selected and applied between 80:10:10 and 96:2:2, and depending on the characteristics of the electrode active material, more polymer binder or more conductive material may be included.

[0060] Hereinafter, specific embodiments of the present invention will be described with reference to FIGS. 3 to 5.

[0061] Figure 3 is a diagram showing the SEM analysis results of an electrode for a secondary battery including an electron-conducting flame-retardant layer. Figure 4 shows the measurement and comparison results of self-extinguishing time according to the presence or absence of the electron-conducting flame-retardant layer in the electrode. Figure 5 is a diagram showing the analysis results of cell characteristics according to the presence or absence of the electron-conducting flame-retardant layer in the electrode.

[0062] <1st Example>

[0063] The first embodiment of the present invention relates to a method for inserting an electron-conducting flame-retardant layer between an anode current collector and an active material layer. In the first embodiment, considering the solubility between the polymer binder, the flame retardant, and the solvent, a flame-retardant layer was prepared using a paraffin polymer binder and a triphenyl phosphate (TPP) flame retardant.

[0064] At this time, a slurry was prepared by mixing carbon black into a xylene solvent, which has high solubility for both paraffin and TTP. The mixed slurry was prepared by mixing carbon black in a 7:3 weight ratio relative to paraffin into a solution in which paraffin and TTP were mixed in a 2:1 weight ratio.

[0065] In the first embodiment, it was manufactured to 25 μm through doctor blade wet coating, and as described above, to remove the flame retardant exposed on the surface, it was washed using an acetone solvent that can selectively dissolve only the flame retardant without dissolving the polymer binder.

[0066] Al foil (thickness: 13 μm) was used as the current collector, and all drying was performed by vacuum drying at 55 degrees.

[0067] As the cathode active material, LiCoO2, a conductive agent, and a binder were mixed in a weight ratio of 92:4:4 in n-methyl-2-pyrrolidone solvent. The cathode active material composite was placed at 17.2 mg / cm² on top of the electrically conductive inner layer. 2 It was coated to a certain degree, and after drying, it was pressed using a roll press to achieve 80% of the initial thickness. Figure 3 shows the flame-retardant inner layer between the active material layer and the current collector. When checking via SEM whether the flame-retardant inner layer between the active material layer and the current collector was well formed, it can be seen that an inner layer of uniform thickness has been inserted.

[0068] <2nd Example>

[0069] In the second embodiment of the present invention, the ignition suppression characteristics of an electrode containing an electronically conductive flame-retardant layer prepared according to the first embodiment are to be verified. To this end, in the second embodiment, an electrolyte containing 5 wt% of fluoroethylene carbonate added to 1 M LiPF6 (EC / DMC 1 / 1 vol) was used.

[0070] The amount of electrolyte contained in the electrode was calculated by the difference between the weight measured after immersing the electrode in an excess amount of electrolyte for 6 hours and the weight measured before immersion. Subsequently, the time required for complete extinguishment was measured by exposing the electrode to direct fire, and the self-extinguishing time (SET) was derived using Equation 1 below.

[0071] [Equation 1]

[0072] Self-extinguishing time (SET) = Time taken from ignition to complete extinguishment / (Weight of electrode after electrolyte impregnation - Weight of electrode before electrolyte impregnation)

[0073] (Comparative Example 1)

[0074] In Comparative Example 1, the self-extinguishing time measurement in the second embodiment was performed on a commercially available electrode without an electronically conductive internal flame-retardant layer. It was manufactured with the same composition as the active material layer in the first embodiment, and the loading level of the active material composite was 17.45 mg / cm² 2 It was applied to the extent of the initial thickness. After drying, it was manufactured by applying pressure through a roll press to 80% of the initial thickness, and the self-extinguishing time was measured in the same way as in the second embodiment.

[0075] As shown in Fig. 4, it can be confirmed that an electrode containing an electronically conductive flame-retardant layer exhibits superior self-extinguishing properties.

[0076] <3rd Example>

[0077] In the third embodiment, the cycle characteristics of a lithium-ion secondary battery are to be verified using a positive electrode containing the electrically charged flame-retardant layer of the first embodiment. To this end, a pouch-type secondary battery was manufactured using commercially available natural graphite (NG) as the negative electrode material and an electrolyte containing 5 wt% fluoroethylene carbonate added to 1M LiPF6 (EC / DMC 1 / 1 vol).

[0078] Afterwards, a sufficient impregnation time of at least 15 hours was allowed so that the liquid electrolyte could sufficiently wet the electrode. To evaluate the capacity at different charge / discharge rates, charge / discharge cycles were performed 5 times each at 0.2C, 0.3C, 0.5C, 1C, and 2C at room temperature.

[0079] (Comparative Example 2)

[0080] For comparison with the third embodiment, a capacity evaluation was performed according to the charge / discharge rate of the secondary battery using the same electrode as Comparative Example 1. At this time, both the negative electrode material and the electrolyte were conducted under the same conditions as the third embodiment, and the evaluation method was also the same.

[0081] Referring to FIG. 5, it can be seen that in the case of a cell using an anode containing an electronically conductive flame-retardant layer through the third embodiment and comparative example 2, uniform cycle characteristics and Coulomb efficiency are maintained within a range where cell characteristics are not impaired compared to a cell using a conventional commercial electrode.

[0082] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0083] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0084] 1: Electrode for secondary battery 100: Active material layer 200: Electronically conductive flame retardant layer 300: Whole house

Claims

Claim 1 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein the electrode comprises a current collector, an active material layer, and an electronically conductive flame-retardant layer provided between the current collector and the active material layer, wherein the electronically conductive flame-retardant layer comprises a conductive material, a flame retardant, and a polymer binder, wherein the polymer binder is composed of a material that is electrochemically stable within a driving voltage and is not soluble in an electrolyte and a washing solvent but is soluble in a slurry solvent, wherein the electronically conductive flame-retardant layer is a composite polymer thin film in which the polymer binder forms a continuous phase matrix, wherein the flame retardant is encapsulated by being captured inside the polymer binder matrix while dissolved in the slurry solvent, and the flame retardant exposed on the surface of the polymer binder matrix is ​​removed through a washing process using a washing solvent, wherein the slurry solvent is a solvent capable of dissolving both the polymer binder and the flame retardant, and wherein the flame retardant is composed of a material capable of dissolving both the slurry solvent and the washing solvent. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein, in claim 1, the coating of the electronically conductive flame-retardant layer is performed based on at least one of dip coating, rod coating, knife coating, blade coating, roll coating, gravure coating, and slot coating, which are capable of large-area wet coating. Claim 6 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein, in claim 1, the conductive material comprises at least one of carbon black, acetylene black, ketjen black, carbon nanotube, and graphene. Claim 7 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein, in claim 1, the flame retardant comprises at least one of Trimethyl phosphate (TMP), Triphenyl phosphate (TPP), bis(2-methoxyethoxy)methylallylphosphonate, tris(2,2,2-trifluoroethyl)phosphite, (ethoxy)pentafluorocyclotriphosphazene, ethylene ethyl phosphate, and Tis(2-chloroethyl phosphate). Claim 8 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein, in claim 1, the polymer binder comprises at least one of paraffin, polyethylene oxide, styrene butadiene rubber, nitrile butadiene rubber, polyethylene, polytetrafluoroethylene, and polyvinylidene fluoride. Claim 9 An electrode for a secondary battery comprising an electronically conductive flame-retardant layer, wherein, in claim 1, the electronically conductive flame-retardant layer is formed by coating to have a thickness of 10 to 70 μm with consideration for electrical conductivity. Claim 10 A secondary battery comprising an electrode for a secondary battery according to any one of claims 1 and 5 through 9.

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