The present invention relates to a free standing film for a dry electrode, a method for manufacturing the same, a dry electrode including the same, and a secondary battery. background art [4] Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy and clean energy is increasing. [5] Currently, a secondary battery is a representative example of an electrochemical device using such electrochemical energy, and its use area is gradually expanding. [6] Among these secondary batteries, representative lithium secondary batteries are not only an energy source for mobile devices, but also electric vehicles and hybrid electric vehicles that can replace vehicles using fossil fuels such as gasoline vehicles and diesel vehicles, which are one of the main causes of air pollution. Its use as a power source for automobiles is being realized, and its use area is expanding to applications such as power auxiliary power sources through gridization. [7] The manufacturing process of such a lithium secondary battery is largely divided into three steps: an electrode process, an assembly process, and a formation process. The electrode process is again divided into an active material mixing process, an electrode coating process, a drying process, a rolling process, a slitting process, a winding process, and the like. [8] Among them, the active material mixing process is a process of mixing a coating material for forming an electrode active layer in which an actual electrochemical reaction occurs in the electrode. It is prepared in the form of a slurry having fluidity by mixing a binder for binding and adhesion to the current collector, and a solvent for imparting viscosity and dispersing particles. [9] In this way, the mixed composition for forming the electrode active layer is also referred to as an electrode mixture in a broad sense. [10] Thereafter, an electrode coating process of applying the electrode mixture on the electrically conductive current collector and a drying process of removing the solvent contained in the electrode mixture are performed, and the electrode is additionally rolled to manufacture a predetermined thickness. [11] Meanwhile, as the solvent contained in the electrode mixture evaporates during the drying process, defects such as pinholes or cracks may be induced in the previously formed electrode active layer. In addition, since the inside and outside of the active layer are not dried uniformly, the particle floating phenomenon caused by the difference in solvent evaporation rate, that is, the particles of the area dried first float and form a gap with the area dried relatively later, resulting in electrode quality. this may deteriorate. In particular, in the case of thick film coating, it takes more time to evaporate the solvent when drying the electrode, and since the floating phenomenon of the relatively light conductive material and binder intensifies, there is a fatal disadvantage that it is difficult to manufacture a high-quality electrode. . [12] Therefore, in order to solve the above problem, a drying device capable of controlling the evaporation rate of the solvent while uniformly drying the inside and outside of the active layer is being considered, but these drying devices are very expensive and require considerable cost and time to operate. As it is required, there are disadvantages in terms of manufacturing processability. [13] Therefore, in recent years, studies on manufacturing a dry electrode that does not use a solvent have been actively conducted. [14] The dry electrode is generally manufactured by laminating a free standing film including an active material, a binder, a conductive material, and the like and manufactured in a film form on a current collector. [15] Therefore, it is attracting attention as an innovative technology capable of manufacturing a thick film electrode, eliminating the need for the use of organic solvents harmful to the human body, and simultaneously solving high process costs due to a long drying furnace. [16] On the other hand, when manufacturing such a dry electrode, polytetrafluoroethylene (PTFE) powder is mainly used as a binder, and this PTFE is inside primary particles having a diameter of several hundred nm or less (-CF 2-CF 2 ) The long fibrous tissue with n atomic arrangement is aligned one after the other, and when subjected to shear force under certain conditions, it is pulled out in a long fibrous form, and these PTFE nanofibers connect the active material and the conductive material like a rope to form an electrode. play a role in maintaining [17] However, since the PTFE is easily fibrous even by a very small shear force at room temperature (above 19° C.), there is a fatal disadvantage in that it coagulates with surrounding PTFE particles even with slight movement. [18] Therefore, in such a dry electrode, the key is a technology that can uniformly disperse the primary PTFE particles under process conditions where no shear force is applied, and through this, a technology that can realize an electrode by binding the active material through fiberization with only a small amount of PTFE development is urgently needed. DETAILED DESCRIPTION OF THE INVENTION technical challenge [19] The present invention is to solve the above problems, a free standing film capable of improving battery performance by enabling uniform dispersion of PTFE primary particles to increase the efficiency of PTFE binder application and forming a solid conductive network It is an object to provide, and a manufacturing method thereof. [20] Another object of the present invention is to provide a dry electrode including the free standing film and a secondary battery including the same. means of solving the problem [21] A free standing film according to an embodiment of the present invention, [22] As a free standing film for dry electrodes, [23] The free standing film includes an active material, a binder including a fibrous polymer, and a carrier, [24] The carrier is characterized in that it is surface oxidation-treated carbon fiber (Oxidized Vapor Grown Carbon Fibers, Ox-VGCF). [25] At this time, the fibrous polymer may be fibrous to bind the active material and the carrier. [26] In one specific example, the support may be a carbon fiber in which the surface oxygen functional group is increased by surface oxidation treatment, and at this time, the support may include 5 to 15 wt% of the surface oxygen functional group based on the total weight can [27] In addition, the carrier may have an average diameter of 50 nm to 500 nm, an average length of 1 μm to 30 μm, and a specific surface area of 10 m 2 /g to 150 m 2 /g. [28] Moreover, the graphitization degree (ID/IG ratio) of the support may be 0.1 to 2.0. [29] Also, in one specific example, the carrier may be included in an amount of 0.1% to 10% by weight based on the total weight of the free standing film. [30] In one specific example, the fiberized polymer may be polytetrafluoroethylene (PTFE). [31] A method for manufacturing the free standing film according to another embodiment of the present invention, [32] (a) obtaining a mixture by mixing a binder and a carrier containing a fiberized polymer; [33] (b) mixing the mixture and the active material together and mixing at high shear to obtain a fiberizing composition; and [34] (c) molding the fiberization composition into a film form; [35] including, [36] The carrier is characterized in that it is surface oxidation-treated carbon fiber (Oxidized Vapor Grown Carbon Fibers, Ox-VGCF). [37] At this time, the polymer capable of fiberization may be polytetrafluoroethylene (PTFE). [38] In one specific example, the mixing of the step (a) is simple mixing of the binder and the carrier containing the fiberization polymer at 19 ° C. or less, or after the mixing, the binder and the carrier mixture containing the fiberization polymer It can be carried out by putting it into a grinder together. [39] Here, the grinder may be an air jet-mill. [40] In this case, the mixture may have a structure in which the primary particles of the fibrous polymer are uniformly dispersed and supported on the surface of the carrier. [41] In one specific example, the high shear mixing of step (b) may be performed for 1 minute to 30 minutes in the range of 10 rpm to 500 rpm. [42] In one specific example, the forming of step (c) may be performed by a hot rolling method using a calender. [43] Meanwhile, a dry electrode according to another embodiment of the present invention includes a current collector and the free standing film formed on the current collector, and the current collector has a structure in which a primer layer is coated on a metal foil It is characterized by being [44] In addition, according to an embodiment of the present invention, a secondary battery is provided in which an electrode assembly including the dry electrode, the counter electrode, and the separator is embedded in a battery case together with a lithium-containing non-aqueous electrolyte. Brief description of the drawing [45] 1 is a SEM picture according to a reference example. [46] Figure 2 is a SEM picture according to Preparation Example 1 of the present invention. [47] 3 is a SEM photograph of the fiberizing composition according to Example 1. Mode for Carrying Out the Invention [48] Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. [49] The terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor may appropriately define the concept of terms in order to best describe his/her invention. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is. [50] Terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. [51] Also, throughout the specification, when it is said that a certain part "includes" a certain component, this is not particularly contrary to the description. More about this source textSource text required for additional translation information Send feedback Side panels History Saved Contribute 5,000 character limit. Use the arrows to translate more.It means that other components can be further included, rather than excluding other components unless present. [52] [53] According to one embodiment of the present invention, as a free standing film for a dry electrode, [54] The free standing film includes an active material, a binder including a fibrous polymer, and a carrier, [55] The carrier is provided with a free standing film that is surface oxidized carbon fiber (Oxidized Vapor Grown Carbon Fibers, Ox-VGCF). [56] At this time, the fibrous polymer may be fibrous to bind the active material and the carrier. As such, in the free standing film for dry electrodes, since the fibrous polymer binds and connects other powders like a rope without a solvent while being fibrous, and plays a role in binding each other, their dispersibility is very important. If the dispersion is not well done, it is impossible to manufacture a free-standing film at all, or even if it is produced, it is difficult to secure the physical properties of the free-standing film. This can drop drastically. [57] In this regard, the inventors of the present application, when the binder containing the fiberization polymer is added alone during mixing for the production of a free standing film, the fiberization polymer nanoparticles exist in a dense state as shown in FIG. 1 below, and their It was confirmed that the primary particles are not easily aggregated and dispersed even with a small shear force, so that the free standing film cannot be firmly manufactured, resulting in a significant drop in efficiency, affecting electrode properties and deteriorating battery characteristics. [58] Accordingly, at the end of in-depth research, it was confirmed that the dispersion of the fiberization polymer was easy when the carrier was first mixed with a binder containing the fiberization polymer and used for producing a free standing film. In particular, the above Surface oxidation-treated carbon fibers (Oxidized Vapor Grown Carbon Fibers, Ox-VGCF), the surface oxygen functional group is introduced to the surface of the Ox-VGCF, and the nano-sized fibrous polymer primary particles are formed on the surface of the carrier by the increased oxygen functional group It was confirmed that it was easily adsorbed to and dispersed more easily. In addition, when such a mixture is then mixed with an active material to form a fiber, it is possible to bind the active material as a whole, and it is confirmed that the performance of a dry electrode and a battery using the same can be improved, and the present invention has been completed. [59] In this case, the support may have a surface oxygen functional group increased to 5 to 15 wt%, specifically 8 to 12 wt%, compared to VGCF not subjected to surface oxidation treatment. [60] The content of the oxygen functional group on the surface may be performed by Elemetal Analysis. Specifically, the elemental content of C, H, and N is measured for the support through elemental analysis equipment (CHN-coder MT-5, Yanako), It can be measured by calculating the oxygen content (Oxygen Differential) by reflecting the amount of residual ash. [61] In this way, when the surface oxygen functional group is sufficiently included, it is preferable because the nano-sized fibrous primary particles are easily adsorbed on the surface of the carrier, but when included in an excessively large amount, there is a problem of side reaction on the surface electrochemically. , which is not desirable. [62] In addition, the carrier may have an average diameter of 50 nm to 500 nm and an average length of 1 μm to 30 μm. More specifically, the average diameter may be 100 nm to 200 nm, and the average length may be 1 μm to 15 μm. [63] Outside the above range, if the average diameter is too small, the radius of curvature becomes small, making it difficult to support due to mutual interference between the primary particles of the fibrous polymer. not. In addition, if the average length is too long, the powder fluidity is greatly reduced and the efficiency of dispersion/carrying is reduced. If the average length is too short, the aggregation rate of the carriers increases, and it is not preferable to form a long conductive network between active materials. Therefore, in order to sufficiently disperse the binder containing the fiberized polymer of the present application, as in the above range, it is preferable to use Ox-VGCF having a predetermined thickness, excellent linearity, and surface oxygen functional groups. [64] The average diameter and average length of the carrier can be measured by SEM. More specifically, the carrier solution diluted to 1 wt% in acetone solvent was dropped on a Si wafer and dried, and measured by SEM (Scanning Electron Microscopy, JEOL, JSM-7500F), and the diameter and length of 300 objects were measured. The average value of can be obtained. [65] In addition, the specific surface area of the carrier for uniform dispersion of the fiberized polymer may be 10 m 2 / g to 150 m 2 / g, and specifically, 10 m 2 / g to 100 m 2 / g. [66] The specific surface area can be measured by the Brunauer-Emmett-Teller (BET) method. For example, it can be measured by the BET 6-point method by adsorption of nitrogen gas using a specific surface area measuring instrument (Bell Japan Inc, Belsorp-II mini). [67] When having such a specific surface area, the fibrous polymer can be easily dispersed and supported. Outside the above range, if the specific surface area is too small, dispersion of the fibrous polymer is not easy, and if the specific surface area is too large, gas or the like is generated due to a side reaction with the electrolyte, which is not preferable. [68] In addition, the carrier is made of a carbon material with excellent electrical conductivity and has a cylindrical tube shape with excellent linearity and has a wide specific surface area, so that the formation of a conductive network between active materials in the free standing film can be further strengthened. As possible, the inclusion of the carrier is more preferable. [69] Moreover, the graphitization degree (ID/IG ratio) of the carrier having an increased surface oxygen functional group may be 0.1 to 2.0. [70] The degree of graphitization (ID/IG ratio) is obtained through Raman spectrum measurement. In the Raman spectrum, the G peak near 1590 cm -1 originates from the E2g vibration mode of the sp2 bond of carbon, and the D peak near 1350 cm -1 appears when there is a defect in the sp2 bond of carbon. The lower the ID/IG ratio (D/G Peak Intensity Ratio), the higher the degree of graphitization. Accordingly, when using carbon-based particles having a high degree of graphitization, the capacity and electrical characteristics of the battery may be improved due to the high electrical conductivity of the carbon-based particles. [71] Meanwhile, the carrier may be included in an amount of 0.1% to 10% by weight, and specifically, 0.5% to 10% by weight based on the total weight of the free standing film. [72] Outside of the above range, when included in too much content, the active material content may be less than the limit of the effective side, which is not preferable in terms of energy density. On the other hand, when included too little, the fiberization polymer is sufficient. Dispersion effect is not obtained. [73] Meanwhile, the fibrous polymer may be polytetrafluoroethylene (PTFE). Such a fiberization polymer may be included in an amount of 50% by weight or more, and may be 100% by weight based on the total weight of the binder. [74] In addition, the binder may further include polyethylene oxide (PEO), polyvinylidene fluoride (PVdF), and polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) in addition to the polytetrafluoroethylene. Binders may be additionally included, and may vary depending on whether the dry electrode is an anode or a cathode. [75] The active material may also vary depending on whether the dry electrode is an anode or a cathode. [76] In order to prepare the free standing film for forming the dry positive electrode, the active material is not limited as long as it is in the form of lithium transition metal oxide, lithium metal iron phosphate, or metal oxide, for example, lithium cobalt oxide (LiCoO 2 ), lithium layered compounds such as nickel oxide (LiNiO 2 ) or compounds substituted with one or more transition metals; lithium manganese oxides such as Li 1+xMn 2-xO 4 (where x is 0 to 0.33), LiMnO 3, LiMn 2O 3, LiMn 2O 3, and LiMnO 2; lithium copper oxide (Li 2 CuO 2 ); Vanadium oxides, such as LiV 3O 8, LiFe 3O 4, V 2O 5, and Cu 2V 2O 7; Formula LiNi 1-xM xO 2 where M = Co, Mn, Al, Cu, Fe, Mg, Ca, Zr, Ti, B, P, W, Si, Na, K, Mo, V, Nb, Ru or Ga, and x = 0.01 to 0.3) Ni site type lithium nickel oxide; Formula LiMn 2-xM xO 2 where M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1 or Li 2Mn 3MO 8 where M = Fe, Co, Ni, Cu or a lithium manganese composite oxide represented by Zn); LiMn 2 O 4 in which Li part of the formula is substituted with an alkaline earth metal ion; lithium metal phosphate LiMPO 4 (where M is M = Fe, CO, Ni, or Mn), disulfide compounds; Fe 2 (MoO 4) 3 etc. can be mentioned, but it is not limited only to these. [77] In order to manufacture the free-standing film for forming the dry negative electrode, the active material may include carbon such as non-graphitizable carbon and graphite-based carbon; Li xFe 2O 3 (0≤x≤1), Li xWO 2 (0≤x≤1), Sn xMe 1-xMe' yO z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P , Si, State More about this source textSource text required for additional translation information Send feedback Side panels History Saved Contribute 5,000 character limit. Use the arrows to translate more.Groups 1, 2, and 3 elements of the Table of Elements, halogens; 0