Transfer release film, lithium electrode using the same, and method for manufacturing the same

Abstract

The transfer release film according to the present invention includes a substrate, a release layer formed by coating one surface of the substrate with a release composition containing an ion-conductive polymer resin and a solvent, and a lithium vapor-deposited layer formed by vapor deposition on the upper surface of the release layer. In the transfer release film according to the present invention having such a configuration, the release layer detaches from the substrate and is transferred to the electrode together with the lithium vapor-deposited layer, thereby jointly performing the role of a protective layer for the lithium vapor-deposited layer.

Description

[Technical Field]

[0001] The present invention relates to a transfer release film, and more specifically, to a transfer release film in which a lithium vapor deposition layer is formed on the surface of a release layer so that both the release layer and the lithium vapor deposition layer are transferred, as well as a lithium electrode using the same and a method for manufacturing the same. [Background technology]

[0002] In recent years, with the increasing prevalence of mobile phones, video cameras, laptops and PCs, and even electric vehicles, interest in energy storage technologies has grown significantly. This expansion of application areas has led to increasingly concrete efforts in the research and development of electrochemical devices. Electrochemical devices are a particularly noteworthy area in this regard, with a focus on the development of rechargeable secondary batteries. In recent years, research and development has been actively pursued on the design of new electrodes and batteries to improve the capacity, density, and specific energy of such secondary batteries.

[0003] In relation to research and development on electrodes and batteries for such secondary batteries, research is underway to mitigate cycle characteristics and volume expansion using quasimetallic oxides such as silicon oxide (SiOx). Among these, silicon (Si) composites, which use silicon-based and carbon-based materials simultaneously, are a method developed to increase capacity and charge / discharge life while minimizing the volume expansion of silicon-based materials. By coating silicon-based materials with carbon, the volume expansion of silicon-based particles is reduced while improving the electrical conductivity between active material particles and the electrochemical properties with respect to the electrolyte, thereby increasing the lifespan of the secondary battery. Furthermore, in this case, to solve the problem of irreversible phase formation by silicon-based materials during initial charge / discharge, which reduces initial charge / discharge efficiency, the initial efficiency of the negative electrode active material can be improved by pre-compositing quasimetallic oxides and lithium so that the quasimetallic oxide contains lithium. This reduces the generation of irreversible phases such as lithium oxide and lithium metal oxide during the initial charge / discharge of the battery.

[0004] However, as mentioned above, secondary batteries using lithium have limitations in their manufacturing process due to the reactivity of lithium metal. Contact with oxygen and moisture in the atmosphere is unavoidable during secondary battery assembly, which reduces the battery's lifespan and performance. Furthermore, the growth of lithium dendrites reduces the charge and discharge efficiency of the lithium electrodes. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention was devised to solve the above-mentioned problems, and the problem that the present invention aims to solve is to provide a transfer release film for manufacturing a lithium electrode having a structure that can block contact with the atmosphere during the process of forming the lithium electrode of a lithium secondary battery, thereby reducing the diffusion barrier of lithium metal and preventing the growth of lithium dendrites, as well as a lithium electrode using the same and a method for manufacturing the same.

[0006] Furthermore, another problem that the present invention aims to solve is to provide a transfer release film, a lithium electrode using the same, and a method for manufacturing the same, which can control the transferability of the lithium vapor-deposited layer and control the reactivity between lithium and the substrate, as well as the reactivity with heat and moisture during the formation process of the lithium vapor-deposited layer, by first depositing the lithium vapor-deposited layer onto a separate release film and then transferring it to the current collector together with the release film, rather than directly depositing the lithium vapor-deposited layer onto the current collector.

[0007] Furthermore, another problem that the present invention aims to solve is to provide a transfer release film that can minimize the exposure of lithium metal to the atmosphere during the manufacturing process of lithium electrodes, a lithium electrode utilizing the same, and a method for manufacturing the same.

[0008] The above and other objectives and advantages of the present invention should become apparent from the following description which illustrates preferred embodiments. [Means for solving the problem]

[0009] The above objective is achieved by a transfer release film comprising a substrate, a release layer formed by coating one surface of the substrate with a release composition containing an ion-conductive polymer resin and a solvent, and a lithium vapor-deposited layer formed by vapor deposition on the upper surface of the release layer.

[0010] Preferably, the release layer detaches from the substrate and is transferred to the electrode together with the lithium deposition layer. Preferably, the substrate further includes a coating layer formed on the other side and containing an ion-conductive polymer resin.

[0011] Preferably, the ion-conducting polymer resin is dissolved by the electrolyte provided in the electrode assembly.

[0012] Preferably, the release film for transfer has a peeling force that satisfies the following formulas 1 and 2.

[0013] (Formula 1) 1 <TR< 100 (Formula 2) 1 < FR < 20 Here, TR is the peeling force when the Nitto-31B tape is adhered to the surface of the release layer at room temperature (23°C) before forming the lithium vapor deposition layer on the release layer, and the Nitto-31B tape is held in place while the substrate is gripped to peel the release layer from the substrate at a speed of 0.3 mpm. FR is the peeling force when the Nitto-31B tape is adhered to the surface of the release layer at room temperature (23°C) before forming the lithium vapor deposition layer on the release layer, and the Nitto-31B tape is held in place while the substrate is gripped to peel the substrate from the release layer at a speed of 0.3 mpm. The peeling force unit is gf / inch.

[0014] Preferably, when the transfer release film is peeled off at a speed of 0.3 mpm after adhering the Nitto-31B tape to the surface of the release layer, the peeling force satisfies the following formula 3.

[0015] (Formula 3) 1 < TR1 / TR0 < 5 Here, TR0 is the release force of the release layer before heat treatment, and TR1 is the release force of the release layer after heat treatment at 80°C for 5 hours, with the release force unit being gf / inch.

[0016] Preferably, when the transfer release film is peeled off at a speed of 0.3 mpm after the Nitto-31B tape has been adhered to the surface of the lithium vapor-deposited layer, the peeling force of the release layer that is peeled off together with the lithium vapor-deposited layer from the substrate interface satisfies the following formula 4.

[0017] (Formula 4) 1 ≤ LR ≤ 200 Here, LR is the peeling force of the release layer that is peeled off together with the lithium deposition layer, and the unit of peeling force is gf / inch.

[0018] Preferably, the ion-conductive polymer resin contains at least one selected from cyclic olefin copolymer, polymethylmethacrylate, polyacrylate, polycarbonate, polystyrene, polyurethane, polyimide, and polyethylene naphthalate.

[0019] Preferably, the glass transition temperature (Tg) of the ion-conductive polymer resin is 80 to 150 °C.

[0020] Preferably, the release composition contains 3 to 50 parts by weight of the ion-conductive polymer resin with respect to 100 parts by weight in total.

[0021] Preferably, the solvent is at least one selected from ethyl acetate, methyl acetate, methyl ethyl ketone, toluene, tetrahydrofolic acid, and cyclohexane.

[0022] Preferably, the water contact angle of the surface of the release layer is 65 to 90°.

[0023] Preferably, the water permeability of the release layer is 200 g / m 2 ·day or less.

[0024] Preferably, the ionic conductivity of the release layer is 10 -6 to 10 -1 S / cm.

[0025] Preferably, the surface pencil hardness of the release layer is 3H or more.

[0026] Preferably, the arithmetic mean roughness (Ra) of the substrate is 10 to 2,000 nm.

[0027] Preferably, the thickness of the release layer is 0.2 to 2 μm.

[0028] Preferably, the thickness of the lithium deposition layer is 1.5 to 10 μm.

[0029] Preferably, after cross-cutting the lithium vapor-deposited layer into 100 sections, a Nitto-31B tape is applied to the surface and then peeled off, the remaining lithium vapor-deposited layer on the tape is 10 sections or less.

[0030] Furthermore, the above objective is achieved by a lithium electrode comprising a current collector, a lithium vapor-deposited layer formed on at least one surface of the current collector, and a protective layer formed on the lithium vapor-deposited layer, wherein the lithium vapor-deposited layer and the protective layer are made up of a lithium vapor-deposited layer and the release layer transferred from the above-mentioned transfer release film.

[0031] Furthermore, the above objective can be achieved by a method for manufacturing a lithium electrode, which includes the steps of: coating at least one surface of a substrate with a release composition containing an ion-conductive polymer resin and a solvent to form a release layer; depositing lithium metal on the release layer to form a lithium vapor-deposited layer; and attaching the surface of the lithium vapor-deposited layer to a current collector, and then transferring the release layer and the lithium vapor-deposited layer to the current collector. [Effects of the Invention]

[0032] A transfer release film, a lithium electrode using the same, and a method for manufacturing the same according to one embodiment of the present invention have the effect of minimizing the exposure of lithium to the atmosphere during the electrode manufacturing process, and preventing the growth of lithium dendrites, by first forming a release layer and a lithium vapor deposition layer on a separate substrate, and then transferring both the release layer and the lithium vapor deposition layer to the current collector, instead of directly forming a lithium vapor deposition layer on the current collector during the manufacturing of the lithium electrode.

[0033] Furthermore, according to the present invention, in the process of transferring the lithium vapor-deposited layer to the current collector, the lithium vapor-deposited layer and the release layer are transferred simultaneously, which has the effect that the release layer can function as a protective layer for the lithium vapor-deposited layer and the surface of the current collector.

[0034] Furthermore, according to the present invention, there are effects such as being able to improve the lifespan of secondary batteries by adjusting the thickness of the lithium vapor-deposited layer.

[0035] However, the effects of the present invention are not limited to those mentioned above, and other effects not mentioned should be clearly understood by those with ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawing]

[0036] [Figure 1] This is a cross-sectional view of a transfer release film according to one embodiment of the present invention, in which a lithium vapor deposition layer is not formed on the film. [Figure 2] This is a cross-sectional view of a transfer release film according to one embodiment of the present invention. [Modes for carrying out the invention]

[0037] The embodiments of the present invention will be described below in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be embodied in a variety of different forms and is not limited to the embodiments described herein.

[0038] To clearly illustrate the present invention in the drawings, irrelevant parts have been omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, thicknesses have been enlarged in the drawings to clearly represent multiple layers and regions. Furthermore, where it is stated in this specification that a component is placed "on top of" or "on top of" another component, that component may be placed directly on top of the other component, or there may be an interposed component between them. Conversely, where it is stated that a component is placed "directly on top of" or "directly on top of" another component, there may not be an interposed component.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention pertains. In case of any conflict, this specification, including its definitions, shall prevail. Furthermore, similar or equivalent methods and materials may be used in carrying out or testing the invention, but suitable methods and materials are described herein.

[0040] In this specification, the term “inclusion” means, unless otherwise stated, that other components may be included rather than excluded.

[0041] In this specification, the term “these combinations” means a mixture or combination with one or more of the components described.

[0042] In this specification, the term "and / or" means any combination and all combinations of one or more items described in relation to each other. In this specification, the term "or" means "and / or". In this specification, expressions such as "at least one" or "one or more" preceding a component may complement the overall list of components, but not necessarily the individual components described above.

[0043] Unless otherwise stated, all percentages, parts, ratios, etc., are based on weight. Furthermore, where a quantity, concentration, or other value or parameter is given as a range, preferred range, or preferred upper and lower limit catalog, this should be understood to specifically disclose all ranges formed from any pair of any upper or preferred upper limit and any lower limit or preferred value, regardless of whether the range is disclosed separately.

[0044] Where a range of numerical values ​​is referred to herein, unless otherwise stated, that range is intended to include its endpoint and all integers and fractions within that range. The scope of the present invention is not intended to be limited to the specific values ​​referred to when defining a range.

[0045] In this specification, each component is a concept that includes both singular and plural forms.

[0046] The present invention will be described in detail below with reference to the attached drawings.

[0047] Figure 1 is a cross-sectional view of a transfer release film according to one embodiment of the present invention in which a lithium vapor deposition layer is not formed on the film, and Figure 2 is a cross-sectional view of a transfer release film according to one embodiment of the present invention.

[0048] Referring to Figure 2, a transfer release film according to one embodiment of the present invention includes a substrate 120, a release layer 110 formed by coating one surface of the substrate 120, and a lithium vapor deposition layer 140 formed by vapor deposition on the upper surface of the release layer 110, and may further include a coating layer 130 formed on the other surface of the substrate.

[0049] Generally, lithium secondary batteries have many constraints on their manufacturing process due to their high reactivity. Because contact with oxygen and moisture in the atmosphere is unavoidable during battery assembly, battery life and performance are reduced, and the charging and discharging efficiency of the lithium electrode decreases due to the growth of lithium dendrites. In response to this, the inventors conducted multifaceted research and confirmed that by not directly forming the lithium vapor-deposited layer on the current collector during lithium electrode manufacturing, but instead forming the lithium vapor-deposited layer on a separate substrate and then transferring it to the current collector, the exposure of lithium to the atmosphere during the electrode manufacturing process can be minimized, preventing the growth of lithium dendrites. This led to the completion of the present invention. In this case, conventional release films cannot control their reactivity with lithium metal, heat, or moisture, making it impossible to transfer the lithium vapor-deposited layer. Therefore, by providing a transfer release film that embodies a release layer that is non-reactive with lithium, the processability of the lithium vapor-deposited layer can be ensured, and transferability that allows for easy transfer to the current collector can be ensured.

[0050] 1. Base material 120 The base material 120 of the transfer release film according to one embodiment of the present invention is preferably at least one selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), poly(methylmethacrylate), PMMA, cellulose triacetate (TAC), polypropylene, polyethylene, and polycarbonate.

[0051] In one embodiment, the arithmetic mean roughness (Ra) of the substrate 120 is preferably 10 to 2,000 nm, and more preferably 10 to 100 nm. If the arithmetic mean roughness (Ra) of the substrate 120 is less than 10 nm, the adhesion between the release layer 110 and the surface of the substrate 120 improves, making it impossible to obtain transferability in which both the release layer 110 and the lithium vapor deposition layer 140 are transferred. If it exceeds 2,000 nm, the adhesion between the substrate 120 and the vapor deposition drum decreases during the formation process of the lithium vapor deposition layer 140, making it impossible to ensure vapor deposition processability.

[0052] 2. Release layer 110 The release layer 110 is formed by applying a release composition to one surface of the substrate 120. Hereinafter, the release layer 110 is formed by coating one surface of the substrate 120 and does not undergo any change in physical properties over time due to the thermal and moisture environment, and the reaction with the lithium vapor deposition layer 140 is controlled when the lithium vapor deposition layer 140 is formed on the release layer 110.

[0053] In one embodiment, the release composition that forms the release layer 110 comprises an ion-conductive polymer resin and a solvent.

[0054] In the present invention, the ion-conducting polymer resin contained in the release composition forming the release layer 110 exhibits hydrophobic properties with low affinity for water and has excellent moisture barrier properties to the lithium vapor deposition layer 140. Furthermore, in the present invention, the ion-conducting polymer resin can simultaneously function as both a release agent and a binder.

[0055] In one embodiment, the ion-conducting polymer resin preferably contains at least one selected from cycloolefin copolymer (COC), polymethyl methacrylate (PMMA), polyacrylate, polycarbonate, polystyrene, polyurethane, polyimide, and polyethylene naphthalate.

[0056] Furthermore, the glass transition temperature (Tg) of the ion-conducting polymer resin is preferably 80 to 150°C, and more preferably 100 to 130°C. If the glass transition temperature of the ion-conducting polymer resin is less than 80°C, the hardness of the release layer 110 is low, and when the release layer 110 and the substrate 120 are bonded to and peeled off together with the lithium vapor-deposited layer 140 from the transfer target (current collector), the release layer 110 and the substrate 120 do not separate from each other, and therefore the transferability cannot be demonstrated. If the glass transition temperature exceeds 150°C, the hardness of the release layer 110 becomes excessively high, and when wound in a roll form, the flexural modulus of the release layer 110 decreases, causing cracks to occur in the release layer 110 and separation from the substrate 120 occurs.

[0057] Furthermore, the solvent contained in the release composition is a solvent that can easily dissolve ion-conducting polymer resins, and preferably contains at least one solvent selected from ethyl acetate (EA), methyl acetate (MA), methyl ethyl ketone (MEK), toluene, tetrahydrofolic acid (THFA), and cyclohexane. In addition, it is preferable to use a mixture of one or more solvents in the step of applying the release composition onto the substrate 120 to ensure a good appearance.

[0058] In one embodiment, the release composition preferably contains 3 to 50 parts by weight of an ion-conductive polymer resin based on 100 parts by weight in total, and more preferably more than 10 parts by weight and less than 30 parts by weight. When the ion-conductive polymer resin is less than 3 parts by weight, sufficient coating coverage cannot be ensured, the physical properties inherent to the release layer 110 cannot be exhibited, and the transfer characteristics cannot be obtained. When the ion-conductive polymer resin exceeds 50 parts by weight, the viscosity of the release composition becomes high, and a large amount of coating unevenness such as living, rainbow or cloud occurs, resulting in poor appearance.

[0059] In one embodiment, the water contact angle of the surface of the release layer 110 is preferably 65 to 90°. At this time, when the water contact angle of the surface of the release layer 110 is less than 65°, the surface is easily contaminated due to high surface energy, and as the force of contact with the coating layer 130 on the other side increases during winding, it becomes vulnerable to blocking. On the other hand, when the water contact angle of the surface of the release layer 110 exceeds 90°, the slipperiness increases after winding in a roll state or after depositing the lithium deposition layer 140, and appearance defects such as peeling of the winding cross-section and scratches can occur.

[0060] In one embodiment, the water permeability of the release layer 110 is preferably 200 g / m 2 ·day or less, more preferably 180 g / m 2 ·day or less, and most preferably 150 g / m 2 ·day or less. The release layer 110 can achieve the above water permeability with an ion-conductive polymer resin having a low water permeability and serve as a protective layer for the lithium deposition layer 140. If the water permeability of the release layer 110 exceeds 200 g / m 2 ·day, the amount of water permeation becomes excessive, and a problem occurs that the lithium deposition layer 140 cannot be protected from moisture.

[0061] In one embodiment, the ionic conductivity of the release layer 110 is preferably 10 -6 to 10 -1 S / cm, and 10<000001or 10 -2 It is even more preferable that it be S / cm -4 or 10 -3 It is most preferable that the ionic conductivity of the release layer 110 is within the above range. If the ionic conductivity of the release layer 110 satisfies the above range, the rate performance required to drive the secondary battery can be met. Conversely, if the ionic conductivity of the release layer 110 does not satisfy the above range, the rate performance cannot be met.

[0062] Furthermore, the release layer 110 is preferably formed by at least one coating method selected from dip coating, spray coating, spin coating, die coating, roll coating, slot-die coating, bar coating, gravure coating, comma coating, curtain coating, and micro-gravure coating, but is not limited thereto, and a variety of coating methods that can be used in the industry to form a coating layer can be used.

[0063] In one embodiment, the thickness of the release layer 110 is preferably 0.2 to 2 μm, and more preferably 0.3 to 1.5 μm. If the thickness of the release layer 110 is less than 0.2 μm, there is a possibility of reverse peeling occurring during the transfer process, and if the thickness of the release layer 110 exceeds 2 μm, it becomes difficult to proceed with film peeling after the transfer process.

[0064] Furthermore, it is preferable that the surface pencil hardness of the release layer 110 be 3H or higher.

[0065] Furthermore, the ion-conducting polymer resin contained in the release composition dissolves easily in the electrolyte solution and is characterized by the absence of side reactions during or after battery assembly. In particular, the ion-conducting polymer resin is dissolved by the electrolyte provided in the electrode assembly during the process of transferring both the release layer 110 and the lithium vapor deposition layer 140 to the electrode assembly, and does not cause side reactions during or after battery assembly. At this time, the electrolyte solution used to dissolve the ion-conducting polymer resin may contain a mixture of at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate, and halides thereof. These halides may include, but are not limited to, fluoroethylene carbonate (FEC).

[0066] As described above, the release layer 110 is peeled off from the substrate 120 together with the lithium vapor deposition layer 140 and transferred to the object to be transferred (such as a current collector). In this process, the release layer 110 is dissolved and removed by the electrolyte provided in the electrode assembly. In other words, the release layer 110 plays a role in protecting the lithium vapor deposition layer 140 during the process of being transferred to the object to be transferred together with the lithium vapor deposition layer 140, and is dissolved by the electrolyte during this process, allowing the release layer 110 to be removed without any additional steps.

[0067] Furthermore, although Figures 1 and 2 show that the release layer 110 is formed on only one side of the substrate 120, the release layer 110 can be formed on both sides of the substrate 120. Such a release layer 110 prevents the problem of reverse delamination, in which the lithium vapor-deposited layer 140 is transferred to another adjacent substrate 120 that is not a current collector, during the winding process in which the lithium vapor-deposited layer 140 is transferred to the current collector. After the lithium vapor-deposited layer 140 is transferred onto the current collector, the substrate can be easily separated. Moreover, by forming the release layer 110 on both sides of the substrate 120, outgassing, which occurs due to the reaction between the substrate 120 and heat and moisture that may occur during the lithium vapor deposition process in which the lithium vapor-deposited layer 140 is formed, can be prevented.

[0068] Furthermore, the release layer 110 may further include a protective layer between it and the lithium deposition layer 140. The protective layer between the release layer 110 and the lithium deposition layer 140 protects the lithium deposition layer 140 from heat and moisture in addition to the release layer 110.

[0069] 3. Lithium vapor deposition layer 140 A transfer release film according to one embodiment of the present invention includes a lithium vapor-deposited layer 140 formed by vapor deposition on the upper surface of a release layer 110. More specifically, the lithium vapor-deposited layer 140 can be formed as a single layer of lithium vapor-deposited on the release layer 110, and a lithium alloy layer can be formed on the surface of the vapor-deposited lithium metal layer by a gas treatment method as needed. For example, a lithium metal layer can be formed on the release layer 110 by vapor deposition of gaseous lithium metal particles in a vacuum, and a lithium alloy layer composed of Li2CO3 can be formed by introducing CO2 gas onto the lithium metal layer to form the lithium vapor-deposited layer 140. By further forming a lithium alloy layer on the surface of the vapor-deposited lithium metal layer by a gas treatment method in this way, the lithium dendrite suppression effect can be enhanced.

[0070] Furthermore, the thickness of the lithium deposition layer is preferably 1.5 to 10 μm. Such a lithium deposition layer 140 acts as a lithium ion diffusion barrier, preventing the growth of lithium dendrites.

[0071] Furthermore, the lithium alloy layer is preferably formed by depositing at least one lithium alloy selected from Li2CO3, Li2O3, Li3N, LiOH, and LiH, with lithium carbonate (Li2CO3) being the most preferred in terms of stability. However, the lithium alloy is not limited to the substances described above, and any lithium alloy generally used in current collectors of secondary batteries can be used without limitation.

[0072] Furthermore, the thickness of the lithium alloy layer is preferably 1 nm to 1 μm. If the thickness of the lithium alloy layer is less than 1 nm, the lithium dendrite suppression effect is weak, and if it exceeds 1 μm, the density difference with the lithium (Li) metal becomes large, which may cause delamination of the surface and interface of the lithium metal.

[0073] Furthermore, the overall thickness of the lithium vapor-deposited layer 140, which includes the lithium metal layer and the lithium alloy layer, is preferably 1.5 to 10 μm, and more preferably 4 to 8 μm. In this case, if the overall thickness is less than 1.5 μm, the charging and discharging performance of the secondary battery will decrease, and if it exceeds 10 μm, the electrode thickness will become excessively thick.

[0074] 4. Transfer release film 100 In one embodiment of the present invention, the release film for transfer preferably satisfies the peeling force of formula 1.

[0075] (Formula 1) 1 < TR < 100 In Equation 1, TR is the peeling force between the release layer 110 and the base material 120 when the Nitto-31B acrylic adhesive tape is attached to the surface of the release layer 110 at room temperature (23°C), the base material 120 is attached so that it is in contact with the bottom, and the acrylic adhesive tape is gripped and peeled off at a speed of 0.3 mpm (the peeling force when peeling the release layer from the base material). The unit of the peeling force is gf / inch.

[0076] If the value of Equation 1 is 1 or less, the release layer 110 peels off too easily from the substrate 120, resulting in the problem of pre-peeling occurring, where the substrate 120 and the release layer 110 separate from each other at the interface before the transfer process. If the value is 100 or more, a strong force is required during peeling, causing the film to tear or preventing transfer and peeling.

[0077] In one embodiment of the present invention, the release film for transfer preferably satisfies the peeling force of formula 2.

[0078] (Formula 2) 1 < FR < 20 In Equation 2, FR is the peeling force between the release layer 110 and the substrate 120 (the peeling force when peeling the substrate from the release layer) when Nitto-31B tape, an acrylic adhesive tape, is attached to the surface of the release layer 110 at room temperature (23°C), the adhesive tape is attached so that it is in contact with the bottom, and the substrate, which is not an acrylic adhesive tape, is grasped and peeled off at a speed of 0.3 mpm. The unit of the peeling force is gf / inch.

[0079] If the value of Equation 2 is 1 or less, the substrate 120 peels off too easily from the release layer 110, resulting in the problem of pre-peeling where the substrate 120 separates from the interface of the release layer 110 before the transfer process. If the value is 20 or more, a strong force is required during peeling, causing the film to tear or preventing transfer and peeling.

[0080] As described above, both Equations 1 and 2 represent the peeling force between the release layer 110 and the substrate 120, and as mentioned above, they show different peeling forces depending on the peeling method. This is related to the mechanism by which the release layer 110 is peeled from the substrate 120. When the release layer 110, which is relatively stronger and less elastic than the substrate 120, is bent and peeled off while the substrate 120 and adhesive tape are laminated together, cracks occur in the release layer 110 due to the difference in bending rigidity between the PET forming the substrate 120 and the release layer 110, causing separation (transfer). In this process, when the release layer 110 is peeled off with adhesive tape, the release layer 110 has a strong tendency to adhere to the substrate 120, and conversely, when the substrate 120 is peeled off from the release layer 110 that is attached to the adhesive tape after turning it over, the release layer 110 has a strong tendency to adhere to the adhesive tape, resulting in a difference in the peeling force values ​​of Equations 1 and 2.

[0081] In the transfer release film according to one embodiment of the present invention, when Nitto-31B tape is attached to the surface of the release layer 110 and then peeled off at a speed of 0.3 mpm, it is preferable that the peeling force between the release layer 110 and the substrate 120 satisfies the following formula 3.

[0082] (Formula 3) 1 < TR1 / TR0 < 5 In Equation 3, TR0 is the release force of the release layer before heat treatment, and TR1 is the release force of the release layer after heat treatment at 80°C for 5 hours. The unit of release force is gf / inch.

[0083] By satisfying the value in Equation 3, the change in peeling force under high-temperature conditions can be suppressed, thereby solving the problem of peelability at high temperatures.

[0084] In the transfer release film according to one embodiment of the present invention, when Nitto-31B tape is attached to the surface of the lithium vapor-deposited layer 140 and then peeled off at a speed of 0.3 mpm, it is preferable that the peeling force at the interface between the release layer 110 and the substrate 120, that is, when the lithium vapor-deposited layer 140 is formed on the release layer 110 and then peels off together with the lithium vapor-deposited layer 140 from the interface with the substrate 120, satisfies the following formula 4.

[0085] (Formula 4) 1 ≤ LR ≤ 200 In Equation 4, LR is the peeling force of the release layer that is peeled off together with the lithium deposition layer, and the unit of the peeling force is gf / inch.

[0086] If the value of Equation 4 is less than 1, there is a problem of pre-peeling occurring, where the release layer 110 is peeled off too easily and separated from the interface between the release layer 110 and the substrate 120 before the transfer process. If it is greater than 200, there is a problem of the lithium vapor deposition layer 140 not being transferred.

[0087] In the transfer release film according to one embodiment of the present invention, when transferring the lithium vapor-deposited layer 140 to a current collector, it is preferable that the peeling force between the release layer 110 and the substrate 120 is 1 to 100 gf / inch. If the above-mentioned peeling force is less than 1 gf / inch, a pre-peeling defect occurs in which the lithium vapor-deposited layer 140 separates from the substrate 120 together with the release layer 110 in the transfer release film state. If it exceeds 100 gf / inch, a peeling defect occurs in which the substrate 120 is not peeled off after the lithium vapor-deposited layer 140 has been transferred to the current collector.

[0088] Furthermore, in the transfer release film according to one embodiment of the present invention, it is preferable that after cross-cutting the lithium vapor-deposited layer 140 into 100 pieces, adhering Nitto-31B tape to the surface and then peeling it off, the remaining lithium vapor-deposited layer 140 on the tape is 10 pieces or less. If the remaining release layer exceeds 10 pieces, the release layer 110 will remain on the substrate 120 without separating from the substrate 120 together with the lithium vapor-deposited layer 140, thereby reducing the transferability of the lithium layer.

[0089] 5. Coating layer 130 In a transfer release film according to one embodiment of the present invention, the substrate 120 may further include a coating layer 130 formed on the other side (the side opposite the release layer). In this case, the coating layer 130 may have the same configuration as the release layer 110. Such a coating layer 130 can prevent blocking during winding of the transfer release film and can prevent outgassing caused by reaction with the substrate 120 due to heat and moisture that may be generated in the lithium deposition process.

[0090] 6. Lithium electrode and method for manufacturing the same A transfer release film according to one embodiment of the present invention is used in a transfer process in which the release layer 110 and the lithium vapor deposition layer 140 are peeled off together from the substrate 120 and transferred, and the release layer 110 acts as a protective layer (barrier) for the lithium vapor deposition layer 140 during the lithium electrode manufacturing process, thereby preventing the formation of an oxide film (native layer) of lithium metal.

[0091] A lithium electrode according to one embodiment of the present invention includes a current collector, a lithium vapor-deposited layer formed on at least one surface of the current collector, and a protective layer formed on the lithium vapor-deposited layer, wherein the lithium vapor-deposited layer and the protective layer may consist of a lithium vapor-deposited layer and a release layer transferred from the above-mentioned transfer release film.

[0092] Furthermore, a method for manufacturing a lithium electrode according to one embodiment of the present invention includes the steps of: S101, coating at least one surface of a substrate with a release composition to form a release layer; S102, depositing lithium metal onto the release layer to form a lithium deposition layer; and S103, after attaching the surface of the lithium deposition layer to a current collector, transferring the release layer and the lithium deposition layer to the current collector.

[0093] In step S101, where a release composition is coated on at least one surface of the substrate to form a release layer, the release composition has the same composition as the release composition for the transfer release film described above, and redundant explanations are omitted.

[0094] After step S101, in which a release composition is coated on at least one surface of the substrate to form a release layer, the step of forming a protective layer on the release layer may be further included before step S102, in which a lithium vapor deposition layer is formed on the release layer. In this case, the protective layer may include, for example, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and other general protective materials that can protect lithium metal in lithium batteries or secondary batteries may be used.

[0095] Next, step S102, which involves forming a lithium vapor-deposited layer on the release layer, is a step of depositing lithium metal onto the release layer to form a lithium vapor-deposited layer consisting of a single layer of lithium metal. Furthermore, if necessary, a step of forming a lithium alloy layer on the lithium vapor-deposited layer may be further included after step S102, which involves forming the lithium vapor-deposited layer. In this case, the lithium vapor-deposited layer can be formed by a vapor deposition process, and the lithium alloy layer can be formed by a gas treatment method. As an example, a lithium metal layer can be formed on the release layer 110 by depositing gaseous lithium metal particles under vacuum conditions, and then a lithium alloy layer composed of Li2CO3 can be formed by introducing CO2 gas onto the lithium metal layer to form a lithium vapor-deposited layer 140.

[0096] In the unlikely event that a protective layer is formed after step S101, the lithium vapor deposition layer 140 can be formed on the protective layer in step S102, where the lithium vapor deposition layer is formed on the release layer.

[0097] Next, in step S103, in which the release layer and the lithium vapor deposition layer are transferred to the current collector, the release layer 110 and the lithium vapor deposition layer 140 are transferred not only to one surface of the current collector but to both surfaces of the current collector, thereby forming a lithium vapor deposition layer 140 on both surfaces of the current collector and enabling the formation of a thin and uniform lithium vapor deposition layer 140.

[0098] The present invention will be described in more detail below with reference to examples and comparative examples. These examples are provided to further illustrate the present invention, and the scope of the present invention is not limited by these examples. [Examples]

[0099] 1. Confirmation of transferability of different types of release layer resins. To determine suitability for lithium deposition and transfer to current collectors, the transferability according to the type of resin in the release layer was first confirmed.

[0100] Silicone, fluorine, melamine, urethane, acrylic, and olefin resins were each applied to a polyester base film (Toray Advanced Materials, Excell-25μm, arithmetic mean roughness Ra: 20nm) to produce release films with a 0.5μm thick release layer. After leaving each produced film at room temperature (23°C) for one day, 100 cross-hatches were made on the surface of the release layer by crossing 10×10 (mm) lines with a cross-hatch cutter. Nitto-31B tape was then applied and peeled off by rubbing with uniform force, and the remaining film fragments peeled off the release layer on the tape were counted to confirm the retention rate.

[0101] The results showed that for silicone, fluorine, melamine, and urethane-based materials, the retention rate was 100% (all release layers remained on the tape), confirming no transferability. On the other hand, for acrylic and olefin-based resins, the retention rate was 0%, confirming transferability.

[0102] Furthermore, when the process was carried out using the same method except for manufacturing the release layer with a thickness of 1 μm, it was confirmed that in the case of silicone, fluorine, melamine, and urethane-based resins, the residual rate was 100% and there was no transferability, while in the case of acrylic and olefin-based resins, the residual rate was 0% and there was transferability.

[0103] 2. Confirmation of the moisture barrier properties of the release layer coating resin. To determine the suitability of the material as a protective layer for lithium electrodes, the water vapor transmission rate (WVTR) of the release layer was measured to confirm its water barrier properties. Here, the water vapor transmission rate (g / m 2 ·day) means 1m 2 This refers to the amount of water [g] that passes through a film of a certain area in one day. A lower water permeability indicates better water barrier properties.

[0104] First, water was placed in three cups, and each cup was covered with a film consisting of triacetylcellulose film (TAC) coated with PVdF-HFP (TAC / PVdF-HFP), TAC coated with PMMA resin (TAC / PMMA), and TAC coated with COC resin (TAC / COC). After one day, the water permeability of each film was measured using a water permeability measuring device (TSY-T3, Labthink).

[0105] The measurement results showed that the moisture permeability of TAC, TAC / PVdF-HFP, TAC / PMMA, and TAC / COC was 327g, 319g, 157g, and 146g, respectively. Because TAC / PMMA and TAC / COC exhibited excellent moisture barrier properties, it was confirmed that they are suitable coating resins for transferring protective layers for lithium electrodes.

[0106] [Example 1] (1) Manufacturing of release composition and coating layer composition A release composition was prepared using 20 parts by weight of polymethyl methacrylate (PMMA) (IH830HT, manufactured by LX MMA), an ion-conducting polymer resin, 40 parts by weight of EA (Ethyl Acetate), and 40 parts by weight of Toluene, so that the solid content was 20% by weight.

[0107] Furthermore, a coating layer composition was prepared by mixing 5 parts by weight of ion-conducting polymer resin (IH830HT manufactured by LX MMA), 47.5 parts by weight of EA (Ethyl Acetate), and 47.5 parts by weight of Toluene so that the solid content was 20% by weight.

[0108] (2) Manufacturing of a film on which a release layer and a coating layer have been formed. A release composition was applied to one side of a polyester substrate film (Toray Advanced Materials, Excell-25μm, arithmetic mean roughness Ra: 20nm) using a Micro-Gravure coater, and a coating layer composition was applied to the other side. The film was then dried at 140°C for 30 seconds to produce a film with a release layer coating thickness of 800nm ​​and a coating layer thickness of 200nm on the other side.

[0109] (3) Manufacturing of release film with lithium vapor deposition layer formed on it Using the Evaporation Deposition method, a lithium metal layer was deposited onto a release layer at 600°C to produce a transfer release film with a lithium deposition layer 6 μm thick.

[0110] [Example 2] A transfer release film was manufactured in the same manner as in Example 1, except that polymethyl methacrylate (PMMA) (HP101 manufactured by LX MMA) was used as the ion-conducting polymer resin in the release composition.

[0111] [Example 3] A transfer release film was manufactured in the same manner as in Example 1, except that cycloolefin copolymer (COC) (6013 Grade, manufactured by Topas) was used as the ion-conducting polymer resin in the release composition.

[0112] [Example 4] A transfer release film was manufactured in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the base film was 10 nm.

[0113] [Example 5] A transfer release film was manufactured in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the base film was 50 nm.

[0114] [Example 6] A transfer release film was manufactured in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the base film was 2,000 nm.

[0115] [Example 7] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 200 nm.

[0116] [Example 8] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 400 nm.

[0117] [Example 9] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 1,000 nm.

[0118] [Example 10] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 2,000 nm.

[0119] [Comparative Example] [Comparative Example 1] A transfer release film was manufactured in the same manner as in Example 1, except that a water-based acrylic resin (GS0131 manufactured by NIPPON CARBIDE Co., Ltd.) was used as the ion-conducting polymer resin in the release composition.

[0120] [Comparative Example 2] A transfer release film was manufactured in the same manner as in Example 1, except that a water-based acrylic resin (FT9542 manufactured by NIPPON CARBIDE Co., Ltd.) was used as the ion-conducting polymer resin in the release composition.

[0121] [Comparative Example 3] A transfer release film was manufactured in the same manner as in Example 1, except that polymethyl methacrylate (PMMA) (HP05B manufactured by LX MMA) was used as the ion-conducting polymer resin in the release composition.

[0122] [Comparative Example 4] A transfer release film was manufactured in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the base film was 2 nm.

[0123] [Comparative Example 5] A transfer release film was manufactured in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the base film was 8 nm.

[0124] [Comparative Example 6] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 50 nm.

[0125] [Comparative Example 7] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 100 nm.

[0126] [Comparative Example 8] A transfer release film was manufactured in the same manner as in Example 1, except that the coating thickness of the release layer was set to 190 nm.

[0127] Using the transfer release films from Examples 1 to 10 and Comparative Examples 1 to 8, the physical properties were measured in the following experimental examples, and the results are shown in Table 1. The glass transition temperature (Tg) of the ion-conducting polymer resin used in each example and comparative example is shown separately in Table 1 below.

[0128] [Example of experiment] (1) Measurement of transferability Acrylic adhesive tape Nitto-31B was applied to the surface of the lithium vapor-deposited layer of the manufactured examples and comparative examples, and then rubbed with a force of 2 kg and peeled off to confirm whether the release layer and lithium vapor-deposited layer were transferred to the tape and peeled off. ○: Transcribed X: Not transcribed

[0129] (2) Measurement of release force (TR, TR1) For the examples and comparative examples, before forming the lithium vapor deposition layer, the substrate was attached to a cold-rolled stainless steel sheet with double-sided adhesive tape. Then, Nitto-31B adhesive tape was placed on the release layer and pressed with a 2kg pressure roller. After being left at room temperature (23°C) for 5 hours, the release layer was peeled off the substrate by gripping the Nitto-31B adhesive tape, and the peeling force (TR, TR0) between the release layer and the substrate was measured. After being left at 80°C for 5 hours, the peeling force (TR1) when peeling the release layer from the substrate using the same method was measured.

[0130] The peeling force was measured using an AR-1000 (Chem-Instrument) at a peeling angle of 180° and a peeling speed of 0.3 mpm. Five measurements were taken, and the average value (g / inch) was calculated and rounded to the first decimal place. Equation 3 was also calculated based on the measured values ​​and rounded to the second decimal place.

[0131] (3) Measurement of release force (FR) of the mold release layer For the examples and comparative examples, before forming the lithium vapor deposition layer, Nitto-31B adhesive tape was attached to a cold-rolled stainless steel sheet with double-sided adhesive tape so that the adhesive side faced upwards. Then, a film was placed on top of the Nitto-31B adhesive tape so that the release layer was in contact with the adhesive surface, and it was pressed with a 2kg pressure roller and left at room temperature (23°C) for 5 hours. After that, the substrate was peeled off the release layer and the peel force (FR) when peeling the substrate off the release layer was measured.

[0132] The peeling force was measured using an AR-1000 (Chem-Instrument) at a peeling angle of 180° and a peeling speed of 0.3 mpm. Five measurements were taken, and the average value (g / inch) was calculated and rounded to one decimal place.

[0133] (4) Measurement of the peeling force (LR) of the lithium vapor deposition layer For the transfer release films of the examples and comparative examples, the substrate was attached to a cold-rolled stainless steel plate with double-sided adhesive tape, then Nitto-31B adhesive tape was placed on the lithium vapor-deposited layer, and pressure was applied with a 2 kg pressure roller. After being left at room temperature (23°C) for 5 hours, the lithium vapor-deposited layer (lithium layer) and the release layer were peeled off together from the substrate as in Experimental Example 2, and the peel force (LR) was measured.

[0134] (5) Measurement of cross-cut survival rate In the transfer release films of the examples and comparative examples, the surface of the lithium vapor-deposited layer (lithium layer) was cross-cut 10 × 10 (mm) lines using a cross-hatch cutter to create 100 cross-cuts. Then, Nitto-31B tape was attached and peeled off by rubbing with uniform force. The number of film fragments peeled off from the coating surface on the tape was counted, and the remaining percentage was expressed numerically (ASTM D3359, KS M ISO 2409).

[0135] (6) Measurement of coating thickness (dry thickness) The release films for the examples and comparative examples were cut into 5cm x 5cm samples, and the dry thickness of the release layer was measured. The thickness was measured using an ellipsometer (Elli-SE, Ellipsotechnology), and the average value was calculated from three measurements.

[0136] (7) Measurement of arithmetic mean roughness (Ra) The Ra of the substrate film surface was measured using a contact-type three-dimensional roughness measuring instrument (SE3300 manufactured by Kosaka Corporation), and the average value of five repeated measurements at a standard measurement length of 0.08 cm was calculated. [Table 1]

[0137] As shown in Table 1, the transfer release films according to Examples 1 to 10 of the present invention exhibit excellent transferability and peelability. It can be confirmed that even when lithium is deposited in a high-temperature atmosphere and a high-temperature vacuum atmosphere, the transferability and easy peelability remain within an appropriate range, demonstrating their superiority.

[0138] More specifically, by comparing the transfer release films of Examples 2 and 3 of the present invention with those of Comparative Examples 1 to 3, it can be confirmed that the transferability and peeling force properties of the release layer change in a correlated manner depending on the type of release composition resin and the glass transition temperature (Tg).

[0139] Furthermore, comparing the transfer release films of Examples 4 to 6 of the present invention with those of Comparative Examples 4 and 5, it can be confirmed that the arithmetic mean roughness (Ra) of the substrate has a strong correlation with the transferability and peeling force of the release layer, and that the transferability and peeling force of the release layer change depending on the arithmetic mean roughness of the substrate.

[0140] Furthermore, comparing the transfer release films of Examples 7 to 10 and Comparative Examples 6 to 8 of the present invention, it can be confirmed that the coating thickness of the release layer has a strong correlation with transferability and peeling force, and that transferability and peeling force change according to the coating thickness of the release layer. More specifically, it can be confirmed that the thicker the release layer, the better the transferability and ease of peeling, and it can be confirmed that achieving a thickness above a certain level is necessary to ensure transferability.

[0141] As described above, the transfer release film according to the present invention can be appropriately applied according to the desired application, but is not limited thereto. Furthermore, the present invention can provide a transfer release film of excellent quality for use in the field of secondary battery materials, which has excellent transferability and an appropriate range of peeling force, thereby reducing damage to the electrode active material when transferring to the current collector, and can be used according to the application without degrading the function of the battery.

[0142] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements by those skilled in the art, utilizing the basic concepts of the present invention as defined in the following claims, also fall within the scope of the present invention.

Claims

1. Substrate and A release layer is formed by applying a release composition containing an ion-conducting polymer resin and a solvent to one surface of the substrate, A lithium vapor-deposited layer formed by depositing onto the upper surface of the release layer, A release film for transfer, including the above.

2. The release layer is detached from the substrate and transferred to the electrode together with the lithium vapor deposition layer, as described in claim 1.

3. The transfer release film according to claim 1, further comprising a coating layer formed on the other surface of the substrate and containing an ion-conductive polymer resin.

4. The transfer release film according to claim 1, wherein the ion-conducting polymer resin is dissolved by an electrolyte provided in the electrode assembly.

5. The transfer release film according to claim 1, wherein the release force satisfies the following formulas 1 and 2. (Formula 1) 1 < TR < 100 (Formula 2) 1 < FR < 20 TR is the peeling force when, after adhering Nitto-31B tape to the surface of the release layer at room temperature (23°C) before forming the lithium vapor deposition layer on the release layer, the Nitto-31B tape is held in place and the release layer is peeled off the substrate at a speed of 0.3 mpm, and FR is the peeling force when, after adhering Nitto-31B tape to the surface of the release layer at room temperature (23°C) before forming the lithium vapor deposition layer on the release layer, the Nitto-31B tape is held in place and the substrate is peeled off the release layer at a speed of 0.3 mpm, with the peeling force unit being gf / inch.

6. The transfer release film according to claim 1, wherein when Nitto-31B tape is adhered to the surface of the release layer and then peeled off at a speed of 0.3 mpm, the peeling force satisfies the following formula 3. (Formula 3) 1 < TR1 / TR0 < 5 TR0 is the release force of the release layer before heat treatment, and TR1 is the release force of the release layer after heat treatment at 80°C for 5 hours, with the release force unit being gf / inch.

7. The transfer release film according to claim 1, wherein when Nitto-31B tape is adhered to the surface of the lithium vapor-deposited layer and then peeled off at a speed of 0.3 mpm, the peeling force of the release layer that is peeled off together with the lithium vapor-deposited layer from the interface of the substrate satisfies the following formula 4. (Formula 4) 1 ≤ LR ≤ 200 The aforementioned LR is the peeling force of the release layer that is peeled off together with the lithium deposition layer, and the unit of peeling force is gf / inch.

8. The transfer release film according to claim 1, wherein the ion-conducting polymer resin comprises at least one selected from cycloolefin copolymer, polymethyl methacrylate, polyacrylate, polycarbonate, polystyrene, polyurethane, polyimide, and polyethylene naphthalate.

9. The transfer release film according to claim 1, wherein the glass transition temperature (Tg) of the ion-conducting polymer resin is 80 to 150°C.

10. The release composition comprises 3 to 50 parts by weight of an ion-conducting polymer resin per 100 parts by weight of the total, wherein the transfer release film is as described in claim 1.

11. The transfer release film according to claim 1, wherein the solvent is at least one selected from ethyl acetate, methyl acetate, methyl ethyl ketone, toluene, tetrahydrofolic acid, and cyclohexane.

12. The transfer release film according to claim 1, wherein the water contact angle of the surface of the release layer is 65 to 90°.

13. The moisture permeability of the aforementioned release layer is 200 g / m². ２ - A transfer release film according to claim 1, wherein the date is less than or equal to 2 days.

14. The ionic conductivity of the release layer is 10 -6 or 10 －１ A transfer release film according to claim 1, wherein the density is S / cm.

15. The transfer release film according to claim 1, wherein the surface pencil hardness of the release layer is 3H or higher.

16. The transfer release film according to claim 1, wherein the arithmetic mean roughness (Ra) of the substrate is 10 to 2,000 nm.

17. The transfer release film according to claim 1, wherein the thickness of the release layer is 0.2 to 2 μm.

18. The transfer release film according to claim 1, wherein the thickness of the lithium vapor deposition layer is 1.5 to 10 μm.

19. The transfer release film according to claim 1, wherein the lithium vapor-deposited layer is cross-cut into 100 pieces, a Nitto-31B tape is adhered to the surface and peeled off, and the remaining lithium vapor-deposited layer on the tape is 10 pieces or less.

20. Current collector and, A lithium vapor-deposited layer formed on at least one surface of the current collector, The lithium vapor deposition layer includes a protective layer formed on the lithium vapor deposition layer, A lithium electrode comprising the lithium vapor-deposited layer and the protective layer transferred from a transfer release film according to any one of claims 1 to 19.

21. The process involves coating at least one surface of a substrate with a release composition containing an ion-conductive polymer resin and a solvent to form a release layer, The steps include: depositing lithium metal onto the release layer to form a lithium deposition layer; The steps include: attaching the surface of the lithium vapor-deposited layer to the current collector, and then transferring the release layer and the lithium vapor-deposited layer to the current collector; A method for manufacturing lithium electrodes, including the method described above.

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