KR101499787B1 - Highly heat-resistant separator, manufacturing method of the same, and battery including the same - Google Patents

Abstract

The present invention relates to a high-heat-resistant separator, a method for producing the high-heat-resistant separator, and a battery including the high-heat-resistant separator.

Description

TECHNICAL FIELD [0001] The present invention relates to a high heat resistant separator, a method of manufacturing the same, and a battery including the same. BACKGROUND ART [0002]

The present invention relates to a high-heat-resistant separator, a method for producing the high-heat-resistant separator, and a battery including the high-heat-resistant separator.

2. Description of the Related Art In recent years, demand for batteries such as various portable batteries, electric vehicles, and cogeneration devices has been increasing. Among various types of cells, practical cells are mostly composed of chemical cells. Examples of such chemical cells include a primary cell, a secondary cell, and a fuel cell.

BACKGROUND ART [0002] Rechargeable secondary cells that can be charged and discharged are under active research due to the development of mobile electronic devices such as mobile phones, notebook computers, digital cameras, and camcorders. Examples of the secondary battery include a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery. Among them, lithium secondary batteries are superior to nickel-cadmium batteries or nickel-metal hydride batteries, which are widely used as power sources for electronic devices, in terms of operating voltage characteristics and energy density per unit weight, have.

The lithium secondary battery includes a positive electrode formed by applying a positive electrode active material on both surfaces of a positive electrode collector, a negative electrode formed by applying a negative electrode active material on both surfaces of the negative electrode collector, and a separator interposed between the positive and negative electrodes, There is a lithium ion battery manufactured by injecting a liquid organic electrolyte including a lithium salt and an organic solvent into an electrode structure, and a lithium polymer battery manufactured using a polymer electrolyte. Although the lithium ion battery is easy to manufacture and has improved ionic conductivity at room temperature, there is a problem of stability such as electrode corrosion and ignition explosion, and the lithium polymer battery improves the disadvantage of the lithium ion battery. However, The resistance inside the battery is high, which is disadvantageous to a large current discharge, and there is a problem that the discharge characteristic is drastically reduced at a low temperature.

On the other hand, the separator is a core element that plays a role of providing a passage through which the electrolyte component can smoothly move while blocking physical contact between the anode and the cathode in the battery. Particularly, a separator applied to a lithium ion battery, which is a high capacity high voltage battery, must have excellent mechanical properties in order to secure the safety of a lithium ion battery while being thin in order to compensate for low ion conductivity of a liquid organic electrolyte [Sheng Shui Zhang, review on the separators of liquid electrolyte Li-ion batteries ", Journal of Power Sources, Volume 164, P 351-364, 2007]. As the separation membrane for a lithium battery, a microporous membrane made of polyolefin is generally used. However, the polyolefin-based separator has a problem that the internal resistance increases and the cycle life and the large-current discharge characteristics deteriorate because the adhesive force between the polyolefin-based separator and the positive electrode plate is weak at the time of thermocompression at the melting point, do.

Korean Patent Laid-Open Nos. 2006-0072065 and 2007-0000231 disclose separators in which a porous coating layer formed of a mixture of inorganic filler particles and a polymeric binder is formed on one surface or both surfaces of a porous substrate. The inorganic filler particles of the microporous coating layer formed on the porous substrate serve as a kind of passivation that can maintain the physical form, thereby suppressing the heat shrinkage of the porous substrate upon overheating due to malfunction of the electrochemical device, Together, there is an empty space between the inorganic filler particles to form micropores.

Thus, the microporous coating layer formed on the porous substrate contributes to the improvement of the safety of the electrochemical device. The inorganic filler particles used for forming the microporous coating layer according to the prior art include BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), ZrO ₃ , SiO ₂ , Al ₂ O ₃ , TiO ₂ , Li ₃ PO ₄ , Particles such as LixTiy (PO ₄ ) ₃ (0 <x <2, 0 <y <3) are mixed with the polymer binder to cause the small amount of polymer binder to melt or deform at high temperature The thickness of the coating layer of the micrometer level is accompanied by the disadvantage of failing to meet the characteristics of a thin separation membrane capable of high-density charging for high capacity. In addition, a patent has been filed on a separator having a particle size of about 5 占 퐉 on a nonwoven fabric having a pore size of 75 占 퐉 to 150 占 퐉 using a sol-gel method [Degussa, Korean Patent Publication 2005 -7003099], pore control is difficult by utilizing inorganic nano particles, and there is a problem that tensile strength is lower than that of conventional polymer membranes.

Accordingly, the present invention provides a method for producing a high-heat-resistant membrane, a high-heat-resistant membrane prepared according to the method, and a battery including the high-temperature-resistant membrane.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

The first aspect of the present invention provides a method for producing a high-heat-resistant separation membrane, which comprises forming a metal oxide thin film on a surface of a porous polymer substrate and a surface of a pore through a low temperature atomic layer deposition method.

The second aspect of the present invention provides a high-heat-resistant separation membrane comprising a metal oxide thin film formed on a surface of a porous polymer base material and an inner surface of a pore, and is produced according to the first aspect of the present invention.

A third aspect of the present invention provides a battery comprising the high heat-resistant separation membrane according to the second aspect of the present invention.

According to the present invention, it is possible to manufacture a separator having improved thermal characteristics at a high temperature, and also to assemble a battery with high stability to prevent an internal short circuit.

Particularly, the separation membrane according to one embodiment of the present invention can independently produce a thin inorganic separator membrane capable of high-density charging for high capacity, and can improve the mechanical properties and ion mobility It is possible to secure an excellent ion conductivity characteristic having a continuous porous structure.

1 is a schematic view of a separation membrane in which a metal oxide thin film is formed by a low-temperature atomic layer deposition method according to an embodiment of the present invention.
2 is a photograph showing the heat shrinkage behavior of a separation membrane manufactured according to one embodiment of the present invention.
3 is a photograph showing a separation membrane prepared at different temperatures according to one embodiment of the present invention.
FIG. 4 is a graph showing a charge capacity according to C-rate of a separator manufactured at different temperatures according to an embodiment.
5 is a graph showing the discharge capacity according to the number of cycles of the separation membrane manufactured at different temperatures according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is "on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The terms "about "," substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Throughout this specification, the term "combination (s) thereof " included in the expression of the machine form means a mixture or combination of one or more elements selected from the group consisting of the constituents described in the expression of the form of a marker, Quot; means at least one selected from the group consisting of the above-mentioned elements.

Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

Hereinafter, embodiments of the present invention are described in detail, but the present invention is not limited thereto.

The first aspect of the present invention provides a method for producing a high-heat-resistant separation membrane, which comprises forming a metal oxide thin film on a surface of a porous polymer substrate and a surface of a pore through a low temperature atomic layer deposition method.

In the case where most of the conventional atomic layer deposition method or chemical vapor deposition method, which is an upper concept thereof, is used, a closed substrate is used on one side. However, in the present invention, from the outset, the decomposition process of the compound can proceed from the beginning through both sides of the separator, thereby controlling the thin film layer having a thickness of several nanometers and coating the metal oxide layer more densely, Even at a thickness of 400 nm or less, excellent mechanical properties and ion mobility can be exhibited.

In one embodiment of the present invention, the method may further include introducing a hydrophilic functional group into the surface of the porous polymer substrate and the inner surface of the pores using an oxygen plasma before forming the metal oxide thin film, but the present invention is not limited thereto.

In one embodiment of the present invention, the hydrophilic functional group may include, but is not limited to, -OH or -COOH.

In one embodiment of the present application, the porous polymeric substrate is selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, high molecular weight polyethylene, polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyester, But are not limited to, those selected from the group consisting of polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene. The polymer substrate can be used without limitation as long as it is a substrate of a polymer produced by a stretching process, which is a material of a separation membrane of an electrochemical device, or a nonwoven fabric-like substrate formed of a porous net structure by crossing of nanofibers. For example, the porous polymer substrate may have a continuous porous structure having a high porosity and a uniform pore size distribution to facilitate mobility of lithium ions, such as both electrodes when used in a battery, but may not be limited thereto .

In one embodiment of the invention, the metal oxide, Al ₂ O _3, SiO _2, ZrO _2, TiO _2, SnO _2, CeO _2, ZnO, MgO, CaO, SrO, BaO, Na ₂ O, B ₂ O ₃ , Mn ₂ O ₃ , Y ₂ O ₃ , WO ₃ , and combinations thereof.

The precursor used to form the metal oxide thin film by the low-temperature atomic layer deposition method is TMA (tri-methyl-aluminum), MPTMA (methyl-pyrrolidine-tri-methyl-aluminum), ethyl-pyridine-triethyl- aluminum ), EPPDMAH (ethyl-pyridine-dimethyl-aluminum hydride), IPA (C ₃ H ₇ -O) ₃ Al), SiCl ₄ (silicon tetrachloride), TEMASi (tetrakis -ethyl-methyl-amino-Silcon), TiCl 4 (titanium tetrachloride), TTIP (titanium-tetrakis-isoproproxide), TEMAT (tretrakis-ethyl-methyl-amino-Titanium), TDMAT (tetrakis dimethyl-amino-titanium), TDEAT (tetrakis-diethyl-aminotitanium), TEMAH (tetrakis ethylmethylamino- hafnium), TEMAZ (Tetrakis- ethyl-methyl- amido- zirconium), TDMAH -amino-hafnium), tetrakis-dimethyl-amino-zirconium (TDMAZ), tetrakis-diethylamino- hafnium (TDEAH), tetrakis- diethylamino- zirconium (TDEAZ), hafnium tetra- (zirconium tetra-tert-butoxide) , HfCl 4 (hafnium tetrachloride), Ba (C 5 H 7 O 2) 2, Sr (C 5 H 7 O 2) 2, Ba (C 11 H 19 O 2) 2, Sr _{(C 11 H 19 O 2)} 2, Ba (C 5 HF 6 O 2) 2, Sr (C 10 H 10 F 7 O 2) 2, Ba (C 10 H 10 F 7 O 2) 2 Sr (C 10 _{H 10 F 7 O 2) 2} , Ba (C 11 H 19 O 2) -CH 3 (OCH 2 CH 2) 4 OCH 3, Sr (C 11 H 19 O 2) 2 -CH 3 (OCH 2 HC 2) _{4 OCH 3, Ti (OC 2} H 5) 4, Ti (OC 3 H 7) 4, Ti (OC 4 H 9) 4, Ti (C 11 H 19 O 2) 2 (O _{C 3 H 7) 2, Ti} (C 11 H 19 O 2) 2 (O (CH 2) 2 OCH 3) 2, Pb (C 5 H 7 O 2) 2, Pb (C 5 HF 6 O 2) 2 _{, Pb (C 5 H 4 F} 3 O 2) 2, Pb (C 11 H 19 O 2) 2, Pb (C 2 H 5) 4, La (C 5 H 7 O 2) 3, La (C 5 HF _{6 O 2) 3, La (} C 5 H 4 F 3 O 2) 3, La (C 11 H 19 O 2) 3, Zr (OC 4 H 9) 4, Zr (C 5 HF 6 O 2) 4, Zr (C ₅ H ₄ F ₃ O ₂ ) ₄ , Zr (C ₁₁ H ₁₉ O ₂ ) ₄ , Zr (C ₁₁ H ₁₉ O ₂ ) ₂ (OCH ₃ H ₇ ) ₂ , TMSTEMAT [MeSiN = Ta (NEtMe) _{3], TBITEMAT [Me 3 CN} = Ta (NEtMe) 3], TBTDET [Me 3 CN = Ta (Net 2) 3], PEMAT [Ta ((CH 3) (C 2 H 5)) 5], PDEAT [ A metal-organic compound precursor selected from the group consisting of Ta (N (C ₂ H ₅ ) ₂ ) ₅ ], PDMAT [Ta (N (CH ₃ ) ₂ ) ₅ ], TaF ₅ , But may not be limited thereto.

In one embodiment herein, the low temperature atomic layer deposition may be performed at a temperature ranging from about 25 [deg.] C to less than about 80 [deg.] C, but may not be limited thereto. The temperature of the low temperature atomic layer deposition process may be, for example, from about 25 캜 to about 80 캜, from about 25 캜 to about 75 캜, from about 25 캜 to about 70 캜, from about 25 캜 to about 65 캜, From about 50 캜 to about 75 캜, from about 50 캜 to about 70 캜, from about 60 캜 to about 55 캜, from about 25 캜 to about 55 캜, from about 25 캜 to about 50 캜, Less than about 80 占 폚, about 60 占 폚 to about 75 占 폚, or greater than about 60 占 폚 to about 70 占 폚. The method for manufacturing a high-heat-resistant separation membrane according to one embodiment of the present invention is performed at a relatively low temperature, and thus it is possible to prevent pore collapse and particle generation of a porous polymer substrate, which may occur in the case of performing a high-temperature process. In one embodiment of the invention, the temperature of the low-temperature atomic layer deposition is preferably greater than 60 ° C to less than 80 ° C, more preferably greater than 60 ° C to less than 75 ° C and less than 65 ° C to 75 ° C, Preferably higher than 60 DEG C to 70 DEG C or lower.

In one embodiment herein, the low-temperature atomic layer deposition method may be performed in a temperature range of more than 60 DEG C to less than 80 DEG C, but may not be limited thereto.

In general atomic vapor deposition or chemical vapor deposition, the operating temperature is determined according to the characteristics of the precursor used. In many cases, most of the precursors are deposited at a temperature between 100 ° C. and 800 ° C. by the atomic vapor deposition method or the chemical vapor deposition method, The process is carried out.

In one embodiment of the present invention, the thickness of the metal oxide thin film may be about 100 nm or less, but may not be limited thereto. The thickness of the metal oxide thin film may be, for example, from about 1 nm to about 100 nm, from about 10 nm to about 100 nm, from about 20 nm to about 100 nm, from about 30 nm to about 100 nm, from about 50 nm to about 100 nm, from about 60 nm to about 100 nm, from about 70 nm to about 100 nm, from about 80 nm to about 100 nm, from about 90 nm to about 100 nm, from about 1 nm to about 90 nm, From about 1 nm to about 40 nm, from about 1 nm to about 30 nm, from about 1 nm to about 80 nm, from about 1 nm to about 70 nm, from about 1 nm to about 60 nm, from about 1 nm to about 50 nm, nm to about 20 nm, or about 1 nm to about 10 nm. Here, the metal oxide thin film has a thickness of 100 nm or less, thereby improving the thermal characteristics of the separator and preventing the pores of the porous polymer substrate from being blocked, thereby deteriorating the performance of the electrochemical device.

In one embodiment of the present invention, the high-temperature-resistant separator may have a porous structure, but the present invention is not limited thereto. The high-heat-resistant separation membrane including the metal oxide thin film according to the present invention has a porous structure, and thus can serve as a movement passage through which the electrolyte can smoothly move.

In the method of manufacturing a high-heat-resistant membrane according to an embodiment of the present invention, the surface of the porous polymer substrate and the inner surface of the pores may be treated with an oxygen plasma to form a hydroxy group or a carboxyl group. Subsequently, a metal oxide thin film having a thickness of about 100 nm or less can be formed on the surface of the porous polymer substrate and the inner surface of the pore on which the hydroxy group or the carboxyl group layer is formed by a low-temperature atomic layer deposition method. The separation membrane produced by this method has high heat resistance characteristics.

In one embodiment herein, by coating the metal oxide thin film to a nanometer level thickness on the surface of the porous polymer substrate and the pore inner surface using the low temperature atomic layer deposition method, excellent mechanical properties and high ion mobility It is possible to manufacture a separator having a thin thickness capable of high density charging while improving the thermal characteristics and reducing the electrical resistance acting in the battery. In addition, a battery having such a structure can increase the volume of a limited electrode active material in the device, thereby increasing the capacity.

In one embodiment of the present invention, when the atomic layer deposition method is performed at a high temperature of 80 ° C or more in relation to the atomic layer deposition method, damage occurs to the separation membrane itself and contraction of the separation membrane occurs during the process, Shrinkage does not appear. In general, unlike conventional processes using atomic layer deposition at a temperature of 100 ° C or higher, a chemical decomposition reaction of an inorganic precursor is performed using a low-temperature atomic layer deposition method at a low temperature, that is, 75 ° C or less or 70 ° C or less, And the thickness of the separator after coating is not changed by the low-temperature atomic layer deposition method. On the other hand, in the atomic layer deposition process at 60 ° C or lower, the chemical decomposition reaction of the inorganic precursor does not proceed effectively, so that unreacted materials remain much in comparison with the processes at other temperatures, and the coating layer of the inorganic oxide is not coated densely.

The second aspect of the present invention provides a high-heat-resistant separation membrane comprising a metal oxide thin film formed on a surface of a porous polymer base material and an inner surface of a pore, and is produced according to the first aspect of the present invention.

1 is a schematic view of a separation membrane in which a metal oxide thin film is formed by a low-temperature atomic layer deposition method according to an embodiment of the present invention. According to the manufacturing method according to the first aspect of the present invention, the high-temperature-resistant separator may include a metal oxide thin film formed on the surface of the porous polymer substrate and inside the pores through a low temperature atomic layer deposition method. The high heat resistant membrane according to the present invention has a continuous porous structure.

In one embodiment of the present application, the porous polymeric substrate is selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, high molecular weight polyethylene, polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyester, But are not limited to, those selected from the group consisting of polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene. The polymer substrate can be used without limitation as long as it is a substrate of a polymer produced by a stretching process, which is a material of a separation membrane of an electrochemical device, or a nonwoven fabric-like substrate formed of a porous net structure by crossing of nanofibers. For example, the porous polymer substrate may have a continuous porous structure having a high porosity and a uniform pore size distribution to facilitate mobility of lithium ions, such as both electrodes when used in a battery, but may not be limited thereto .

In one embodiment of the invention, the metal oxide, Al ₂ O _3, SiO _2, ZrO _2, TiO _2, SnO _2, CeO _2, ZnO, MgO, CaO, SrO, BaO, Na ₂ O, B ₂ O ₃ , Mn ₂ O ₃ , Y ₂ O ₃ , WO ₃ , and combinations thereof.

In one embodiment of the present invention, the thickness of the metal oxide thin film may be about 100 nm or less, but may not be limited thereto. The thickness of the metal oxide thin film may be, for example, from about 1 nm to about 100 nm, from about 10 nm to about 100 nm, from about 20 nm to about 100 nm, from about 30 nm to about 100 nm, from about 50 nm to about 100 nm, from about 60 nm to about 100 nm, from about 70 nm to about 100 nm, from about 80 nm to about 100 nm, from about 90 nm to about 100 nm, from about 1 nm to about 90 nm, From about 1 nm to about 40 nm, from about 1 nm to about 30 nm, from about 1 nm to about 80 nm, from about 1 nm to about 70 nm, from about 1 nm to about 60 nm, from about 1 nm to about 50 nm, nm to about 20 nm, or about 1 nm to about 10 nm. Here, the metal oxide thin film has a thickness of 100 nm or less, thereby improving the thermal characteristics of the separator and preventing the pores of the porous polymer substrate from being blocked, thereby deteriorating the performance of the electrochemical device.

In one embodiment of the present invention, the high-temperature-resistant separator may have a porous structure, but the present invention is not limited thereto. The high-heat-resistant separation membrane including the metal oxide thin film according to the present invention has a porous structure, and thus can serve as a movement passage through which the electrolyte can smoothly move.

A third aspect of the present invention provides a battery comprising the high heat-resistant separation membrane according to the second aspect of the present invention.

In one embodiment of the present invention, the battery may be a secondary battery, but the present invention is not limited thereto. In one embodiment of the present invention, the secondary battery may include, but is not limited to, an anode, a cathode, a separator, and an electrolyte. In one embodiment of the present invention, the separation membrane is a high-temperature-resistant separation membrane produced by the manufacturing method according to the first aspect of the present invention, and a low-temperature atomic layer deposition method is applied to the surface and pores of the porous polymer substrate And a metal oxide thin film formed through the metal oxide thin film. The high-temperature-resistant separator according to one embodiment of the present invention may have a continuous porous structure, but the present invention is not limited thereto.

In one embodiment of the present invention, the secondary battery may include, but is not limited to, a lithium secondary battery, a lithium-metal secondary battery, a lithium ion battery, a lithium polymer battery, or a lithium ion-polymer battery.

In one embodiment of the present invention, the secondary battery includes a positive electrode formed by applying a positive electrode active material on both surfaces of a positive electrode collector, a negative electrode formed by applying a negative electrode active material on both surfaces of the negative electrode collector, And may include, but is not limited to, an electrically insulating membrane and an electrolyte.

In one embodiment of the present invention, the battery may be a fuel cell, but the present invention is not limited thereto. In one embodiment of the present invention, the separation membrane is a high-temperature-resistant separation membrane produced by the manufacturing method according to the first aspect of the present invention, and a low-temperature atomic layer deposition method is applied to the surface and pores of the porous polymer substrate And a metal oxide thin film formed through the metal oxide thin film. The high-temperature-resistant separator according to one embodiment of the present invention may have a continuous porous structure, but the present invention is not limited thereto.

In one embodiment of the present invention, the fuel cell includes an electrolyte, such as a separator, an acid or a base electrolyte, a cathode electrode, and a cathode electrode, and is an apparatus for generating electrical energy through an electrochemical reaction between the anode and the cathode But may not be limited thereto.

In one embodiment of the present invention, the fuel cell is an apparatus for generating electrical energy by electrochemically reacting a fuel and an oxidant. The type of the fuel cell is not particularly limited and may be, for example, a direct ethanol fuel cell (DEFC), a direct methanol fuel cell (DMFC), a polymer electrolyte fuel cell (PEMFC), Alkaline Fuel Cell (AFC), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC) or Solid Oxide Fuel Cell Fuel Cell, SOFC).

Such a fuel cell is attracting much attention as a transportation power source such as a next-generation automobile or a household power source because a polymer electrolyte fuel cell that generates electricity by using hydrogen, which is clean energy, as a fuel does not discharge any pollutants during the reaction process.

Generally, the electrode reaction of a fuel cell is composed of a hydrogen oxidation reaction at the anode which is the fuel electrode and an oxygen reduction reaction at the cathode which is the oxygen electrode. Since these oxidation and reduction reactions proceed very slowly, the use of a catalyst that increases the reaction rate is essential when used for practical purposes. The cathode and anode of a fuel cell generally use a platinum catalyst, but expensive platinum catalysts are a problem. In particular, in the case of the oxygen reduction reaction occurring at the anode, platinum is used more than the cathode because the reaction rate is slower than the hydrogen oxidation reaction occurring at the cathode.

The second aspect and the third aspect of the present invention respectively relate to a high-heat-resistant separation membrane produced according to the first aspect of the present invention, and a battery including the high-temperature-resistant separation membrane, wherein the parts overlapping with the first aspect of the present invention Although the detailed description has been omitted, the description of the first aspect of the present invention can be applied equally to the second and third aspects of the present application, even if the description thereof is omitted.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are given for the purpose of helping understanding of the present invention, but the present invention is not limited to the following Examples.

[ Example ]

Example  One: Al ₂ O ₃ 20 nm  Preparation of Membrane Coated as Thickness

Alkylated compounds Trimethylaluminum [TMA; Al (CH ₃ ) ₃ , Aldrich] was used as a precursor of Al ₂ O ₃ low-temperature atomic layer deposition. At this time, a pure polyethylene separator (having a porosity of about 40% or more, a thickness of 17 μm to 18 μm, Tonen) is fixed to a jig or a substrate which is easy to permeate through a gas to form a sealed (ie, Lt; / RTI &gt; The surface of the separating membrane, which was hydrophobic, was then reformed to an easy hydrophilic surface using oxygen plasma (pressure of about 200 mTorr to about 400 mTorr, power of about 115 V to about 230 V, O ₂ gas velocity of about 1.4 m ³ / hr, treatment for several minutes). After the TMA was decomposed in an environment of 70 ° C., a 20 nm thick Al ₂ O ₃ thin film was deposited on the polyethylene separator (1.22 Å / cycle). As a result, a separation membrane coated with Al ₂ O ₃ having a thickness of 20 nm was obtained.

Example  2: Al ₂ O ₃ 80 nm  Preparation of Membrane Coated as Thickness

Al ₂ O ₃ -coated films were prepared by atomic layer deposition at 70 ° C in the same manner as in Example 1.

Comparative Example  1: pure polyethylene membrane

In order to compare the characteristics of the membranes of Examples 1 and 2, a pure polyethylene membrane was prepared to have the same size as that of Example 1 and Example 2.

Comparative Example  2: Al ₂ O ₃ 400 nm  Coated PVdF - HFP  Preparation of Membrane

The PVDF-HFP (polyvinylidene fluoride-hexafluoroethylene copolymer, 10% by weight, Kynar) was added to NMP (N-methyl-2-pyrrolidone, Aldrich) and dissolved at room temperature for about 1 hour or longer to obtain a polymer slurry . The prepared polymer slurry was cast on a glass substrate using a doctor blade, dried in an oven at 80 ° C, and then PVdF-HFP membranes were prepared using the phase separation method. The Al ₂ O ₃ coating having a thickness of 400 nm was carried out in the same manner as in Example 1, and the same size was prepared.

Example  3: Preparation of secondary battery

Anode manufacturing

92% by weight of a lithium cobalt composite oxide as cathode active material particles, 4% by weight of carbon black as a conductive material and 4% by weight of polyvinylidene fluoride (PVdF) as a binder were dissolved in N-methyl- (NMP) to prepare a cathode active material slurry. The cathode active material slurry was applied to an aluminum (Al) thin film of a cathode current collector having a thickness of 20 탆 and dried to prepare a cathode, followed by roll pressing.

Cathode manufacture

The solvent was N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) with 96 wt%, 3 wt% and 1 wt% of carbon powder anode active material particles, polyvinylidene fluoride (PVdF) binder and carbon black conductive agent, NMP) to prepare an anode active material slurry. The negative electrode active material slurry was applied to a copper (Cu) thin film as an anode current collector having a thickness of 10 탆 and dried to prepare a negative electrode, followed by roll pressing.

Manufacture of batteries

Cells of a coin cell type were assembled by using the stacking method of the positive electrode, negative electrode, and separator prepared in the above-described Example 1, and an electrolytic solution (ethylene carbonate (EC) / ethylmethyl carbonate ) = 1/2 (volume ratio) and 1 mol of lithium hexafluorophosphate (LiPF6)] to prepare a lithium secondary battery.

Example  4: Manufacture of secondary battery

The positive electrode and the negative electrode were prepared in the same manner as in the preparation of the positive electrode and the negative electrode of Example 3, and then the separator prepared in Example 2 was used instead of the separator of Example 1 in the production of the battery. A secondary battery was manufactured.

Comparative Example  3: Preparation of secondary battery

The positive electrode and the negative electrode were prepared in the same manner as in the preparation of the positive electrode and the negative electrode of Example 3, and then the separator prepared in Comparative Example 1 was used in place of the separator of Example 1 in the production of the battery, A secondary battery was manufactured.

Comparative Example  4: Manufacture of secondary battery

The positive electrode and the negative electrode were prepared in the same manner as in the preparation of the positive electrode and the negative electrode of Example 3, and then the separator prepared in Comparative Example 2 was used in place of the separator of Example 1 in the production of the battery, A secondary battery was manufactured.

Comparative Example  5: at 60 DEG C Al ₂ O ₃ - Preparation of coated membranes

Al ₂ O ₃ -containing Al2O3-coated separator was prepared by atomic layer deposition at 60 ° C in the same manner as in Example 1.

Comparative Example  6: at 80 DEG C Al ₂ O ₃ - Preparation of coated membranes

Al ₂ O ₃ -containing 80 nm-thick Al2O3-coated separator was prepared by atomic layer deposition at 80 ° C.

Comparative Example  7: Al ₂ O ₃ - Preparation of coated membranes

Al ₂ O ₃ -coated films having a thickness of 80 nm were prepared by a high temperature atomic layer deposition method at 100 ° C. in the same manner as in Example 1.

Experimental Example  One: Heat shrinkage  Behavior experiment

The heat shrinkage behavior of the membranes of Examples 1 and 2 and Comparative Examples 1, 2 and 5 to 7 after storage at 160 ° C for 1 hour was confirmed. The results are shown in Fig. 2 and Table 1 below.

Experimental Example  2: Measurement of membrane thickness

The thicknesses of the membranes of Examples 1 and 2 and Comparative Examples 1, 2 and 5 to 7 were measured and the results are shown in Table 1 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 5 Comparative Example 6 Comparative Example 7 Heat shrinkage 2% 0% 95% 10% 60% 3% 40% thickness 17 탆 17 탆 17 탆 23 ㎛ 17 탆 17 탆 17 탆

This is a photograph showing the shrinkage behavior. As shown in FIG. 2, it was found that the heat shrinkage behaviors of Examples 1 and 2 and Comparative Example 1 separator were greatly different when they were stored at 160 ° C. for one hour. In the separator of Comparative Example 1 (polyethylene separator), the heat shrinkage was 95% or more so that the original shape could not be recognized, whereas the separator of Example 1 had less than 2% of heat shrinkage at the separator edge, Almost none.

In addition, as shown in Table 1, the separator of Comparative Example 1 exhibited a heat shrinkage of 95%, the separator of Comparative Example 2 had a heat shrinkage of 10%, while the separator of Example 1 had a 2% Is 0%. It can be seen that the separator according to the present embodiment has excellent heat resistance. On the other hand, the separators of Comparative Example 5, Comparative Example 6, and Comparative Example 7 showed heat shrinkage rates of about 60%, 3%, and 40%, respectively. Thickness of the separator of Comparative Example 2 increased by 35% or more after coating, but the thickness of the separator of the present example did not change by the order of 탆. According to these results, it can be predicted that the separator according to this embodiment does not decrease the battery capacity when used in the battery. In addition, it can be predicted that an Al ₂ O ₃ coated film of 80 nm thickness is prepared by a low-temperature atomic layer deposition at 70 ° C, which is an ideal manufacturing method for coating the inorganic oxide layer most densely with an inorganic precursor at a low temperature.

Experimental Example  3: Membrane-based Coin cell Capacity behavior  Experiment

In order to confirm the capacitive behavior of the cells prepared in Examples 3, 4, 3 and 4, and the batteries prepared in Comparative Examples 5 to 7, discharge was performed at a discharging current of 0.2 C to 3.0 C Capacity values were measured and the results are shown in Table 2 below. At this time, in the following Table 2, the units of the discharge capacity values of Examples and Comparative Examples are mAh / g, which indicates the capacity relative to the mass of the cathode active material.

Discharge current Example 3 Example 4 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 0.2 C 146 147 143 141 143 145 140 0.5 C 143 145 141 140 141 142 138 1 C 140 142 140 138 140 139 132 1.5 C 120 123 120 85 120 120 110 2 C 109 113 103 40 107 111 98 3 C 70 72 53 10 64 67 52

As shown in Table 2, the secondary cell coin cells prepared in Examples 3 and 4 (i.e., the coin cells using the separator prepared in Example 1 and Example 2) exhibited a discharge current of 0.2 C to 3.0 C (That is, a coin cell using a separator of Comparative Example 1 in which a separator used in the prior art was reproduced) manufactured in Comparative Example 3 over the entire length of the coin cell. In addition to these results, as shown in Table 1 above, the separator of Comparative Example 2 used in the secondary battery of Comparative Example 4 has a thickness of 23 탆, which indicates that the separator according to the present invention is superior in battery performance . &Lt; / RTI &gt; Comparing the batteries manufactured using the separators of Comparative Example 5, Comparative Example 6 and Comparative Example 7 with the discharge capacity behavior of the batteries of Example 3 and Example 4, nm thick Al ₂ O ₃ coating layer can be most closely coated with an inorganic oxide layer by using an inorganic precursor at a low temperature to optimally realize a coating effect of an inorganic oxide layer or inorganic particles Able to know.

Experimental Example  4: Temperature dependence of membrane Heat shrinkage  Feature comparison

In order to compare the heat shrinkage characteristics of the separator according to the temperature of the separator prepared in Example 1, Example 2, and Comparative Example 5 to Comparative Example 7, the degree of each damage was observed. As shown in the following Table 3 and FIG. 3, in the high-temperature ALD at 100 ° C, although the separation of the conventional pores is accompanied by damage to the separator itself during the process, the chemical decomposition reaction of the inorganic precursor is normally performed, A defect that can not be evenly coated occurs. On the other hand, in the atomic layer deposition process at 60 캜, the chemical decomposition reaction of the inorganic precursor did not proceed effectively, and unreacted materials remained much in comparison with the processes at other temperatures, and the coating layer of the inorganic oxide was not coated densely. On the other hand, since the separator is relatively dried at 80 ° C, the atomic layer deposition process at 70 ° C rather than 80 ° C is ideally suited for the chemical condensation reaction of the inorganic precursor, .

Example 1 Example 2 Comparative Example 5 Comparative Example 6 Comparative Example 7 Heat shrinkage 2% 0% 60% 3% 40% thickness 17 탆 17 탆 17 탆 17 탆 17 탆

FIGS. 4 and 5 are graphs showing the results of a discharge according to various discharge current densities showing that the atomic layer deposition performed at 70 ° C. is ideally a condition for causing a chemical decomposition reaction of the inorganic precursor to densely coat the inorganic oxide layer. Lt; / RTI &gt; is a graph showing the results of capacity behavior. In the case of polyethylene coated by atomic layer deposition at 70 ° C, the inorganic oxide layer was more densely coated than the samples of other temperature processes to reduce the internal series resistance generated during battery operation, and the hydrophobic surface of the polyethylene The affinity with the liquid electrolyte increases with the decrease of the characteristics, and at the same time, the interaction with the liquid electrolyte and the lithium salt is maximized to increase the number of charge carriers and the like, and the capacity and the power density It can be seen that it has a positive effect.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (18)

A hydrophilic functional group is introduced into the surface of the porous polymer substrate and the inner surface of the pores by using an oxygen plasma,
Forming a metal oxide thin film on the surface of the porous polymer substrate and the inner surface of the pores through a low temperature atomic layer deposition method
Wherein the high-heat-resistant separator has a high heat resistance.
delete The method according to claim 1,
Wherein the hydrophilic functional group comprises -OH or -COOH.
The method according to claim 1,
The porous polymer substrate may be at least one of polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, high molecular weight polyethylene, polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, , A polyether ether ketone, a polyether sulfone, a polyphenylene oxide, a polyphenylene sulfide, and a polyethylene naphthalene.
The method according to claim 1,
Wherein the metal oxide is selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO ₂ , SnO ₂ , CeO ₂ , ZnO, MgO, CaO, SrO, BaO, Na ₂ O, B ₂ O ₃ , Mn ₂ O ₃ , Y ₂ O ₃ , WO ₃ , and combinations thereof.
The method according to claim 1,
The precursor used to form the thin film by the low-temperature atomic layer deposition is TMA (tri-methyl-aluminum), MPTMA (ethyl-pyridine-triethyl-aluminum) Ethyl-pyridine-dimethyl-aluminum hydride (EPPDMAH), IPA (C ₃ H ₇ -O) ₃ Al), SiCl ₄ (silicon tetrachloride), TEMASi (tetrakis -ethyl-methyl-amino-Silcon), TiCl 4 (titanium tetrachloride), TTIP (titanium-tetrakis-isoproproxide), TEMAT (tretrakis-ethyl-methyl-amino-Titanium), TDMAT (tetrakis dimethyl-amino-titanium), TDEAT (tetrakis-diethyl-aminotitanium), TEMAH (tetrakis ethylmethylamino- hafnium), TEMAZ (Tetrakis- ethyl-methyl- amido- zirconium), TDMAH -amino-hafnium), tetrakis-dimethyl-amino-zirconium (TDMAZ), tetrakis-diethylamino- hafnium (TDEAH), tetrakis- diethylamino- zirconium (TDEAZ), hafnium tetra- (zirconium tetra-tert-butoxide) , HfCl 4 (hafnium tetrachloride), Ba (C 5 H 7 O 2) 2, Sr (C 5 H 7 O 2) 2, Ba (C 11 H 19 O 2) 2, Sr _{(C 11 H 19 O 2)} 2, Ba (C 5 HF 6 O 2) 2, Sr (C 10 H 10 F 7 O 2) 2, Ba (C 10 H 10 F 7 O 2) 2 Sr (C 10 _{H 10 F 7 O 2) 2} , Ba (C 11 H 19 O 2) -CH 3 (OCH 2 CH 2) 4 OCH 3, Sr (C 11 H 19 O 2) 2 -CH 3 (OCH 2 HC 2) _{4 OCH 3, Ti (OC 2} H 5) 4, Ti (OC 3 H 7) 4, Ti (OC 4 H 9) 4, Ti (C 11 H 19 O 2) 2 (O _{C 3 H 7) 2, Ti} (C 11 H 19 O 2) 2 (O (CH 2) 2 OCH 3) 2, Pb (C 5 H 7 O 2) 2, Pb (C 5 HF 6 O 2) 2 _{, Pb (C 5 H 4 F} 3 O 2) 2, Pb (C 11 H 19 O 2) 2, Pb (C 2 H 5) 4, La (C 5 H 7 O 2) 3, La (C 5 HF _{6 O 2) 3, La (} C 5 H 4 F 3 O 2) 3, La (C 11 H 19 O 2) 3, Zr (OC 4 H 9) 4, Zr (C 5 HF 6 O 2) 4, Zr (C ₅ H ₄ F ₃ O ₂ ) ₄ , Zr (C ₁₁ H ₁₉ O ₂ ) ₄ , Zr (C ₁₁ H ₁₉ O ₂ ) ₂ (OCH ₃ H ₇ ) ₂ , TMSTEMAT [MeSiN = Ta (NEtMe) _{3], TBITEMAT [Me 3 CN} = Ta (NEtMe) 3], TBTDET [Me 3 CN = Ta (Net 2) 3], PEMAT [Ta ((CH 3) (C 2 H 5)) 5], PDEAT [ A metal-organic compound precursor selected from the group consisting of Ta (N (C ₂ H ₅ ) ₂ ) ₅ ], PDMAT [Ta (N (CH ₃ ) ₂ ) ₅ ], TaF ₅ , Wherein the high heat resistant separator has a high heat resistance.
The method according to claim 1,
Wherein the low-temperature atomic layer deposition method is performed at a temperature range of 25 占 폚 to less than 80 占 폚.
The method according to claim 1,
Wherein the low-temperature atomic layer deposition method is performed in a temperature range of more than 60 占 폚 to less than 80 占 폚.
The method according to claim 1,
Wherein the metal oxide thin film has a thickness of 100 nm or less.
The method according to claim 1,
Wherein the high heat-resistant separation film has a porous structure.
A high heat resistant membrane comprising a metal oxide thin film formed on a surface of a porous polymer substrate and on a pore inner surface thereof, and is produced according to the method of any one of claims 1 and 3 to 10.
12. The method of claim 11,
The porous polymer substrate may be at least one of polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, high molecular weight polyethylene, polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, , Polyether ether ketone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene.
12. The method of claim 11,
Wherein the metal oxide is selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO ₂ , SnO ₂ , CeO ₂ , ZnO, MgO, CaO, SrO, BaO, Na ₂ O, B ₂ O ₃ , Mn ₂ O ₃ , Y ₂ O ₃ , WO ₃ , and combinations thereof.
12. The method of claim 11,
Wherein the metal oxide thin film has a thickness of 100 nm or less.
12. The method of claim 11,
Wherein the high heat-resistant separation membrane has a porous structure.
11. A battery comprising the high-temperature-resistant separator according to claim 11.
17. The method of claim 16,
Wherein the battery is a secondary battery.
17. The method of claim 16,
Wherein the battery is a fuel cell.

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