WO2013151197A1 - Secondary battery using silicon compound and polymer electrolyte, and method for manufacturing same - Google Patents

Abstract

Provided is a secondary battery comprising a positive electrode, a negative electrode, a separation film interposed between the positive electrode and negative electrode, and an ionic liquid with which the separation film is impregnated, wherein both the positive electrode and negative electrode comprise a silicon compound which is a powder-phase sintered body and a binder, wherein the separation film is a solid electrolyte separation film made of a proton-conducting polymer. Also provided is a method for manufacturing a secondary battery, in which the positive electrode and the negative electrode are manufactured by wet coating.

Description

Secondary Battery Using Silicon Compound and Polymer Electrolyte and Manufacturing Method Thereof

The present invention relates to a secondary battery using a silicon compound and a polymer electrolyte, and a method of manufacturing the same. More specifically, a silicon compound, which is a powdery sintered body, is used as a cathode and an anode material, and a hydrogen ion conductive polymer impregnated with an ionic liquid is used. It relates to a secondary battery provided with an electrolyte separator and a method of manufacturing the same.

This application claims priority based on Korean Patent Application No. 10-2012-0036184 filed on April 6, 2012, and all the contents disclosed in the specification and drawings of the application are incorporated in this application.

In recent years, with the rapid development of information and communication equipment, a high energy density type secondary battery which is safe and environmentally friendly is required. As an example of a typical secondary battery, a lithium battery uses a lithium compound as a positive electrode and an organic solvent as an electrolyte, so it is difficult to secure safety at high temperatures, is not environmentally friendly, and the material is very expensive. In particular, in terms of environment, when the lithium battery containing the organic solvent is disposed, there is a disadvantage that causes environmental pollution.

On the other hand, when the silicon compound is used as an electrode material, the manufacturing cost is greatly reduced compared to lithium, and even if the battery is buried in the ground, it is very environmentally friendly and does not generate environmental pollutants. The application of the polymer electrolyte to the battery is a simple battery manufacturing process, it is possible to manufacture a very safe battery even at high temperature, and there is an advantage that can produce a high energy density type battery.

On the basis of this background, the only study to adopt a silicon compound as a material of a secondary battery is currently disclosed in Japanese Patent No. (4685192). The Japanese patent includes many disadvantages, and thus, there are disadvantages in that battery performance is difficult to manifest and costly to manufacture. That is, the disadvantages of the patent are largely in the electrode manufacturing process and the solid electrolyte production. In detail, the Japanese patent was prepared by vacuum depositing a silicon compound as an electrode material during electrode production. This requires an expensive vacuum equipment rather than a wet slurry coating method has a high cost and most difficult electrode thickness control difficult. In addition, the vacuum deposition method has a fatal disadvantage that it is difficult to penetrate ions into the electrode, so that when the electrode is thick from the thin film to the thick film, the output characteristic of the electrode is rapidly decreased. In addition, the above patent has a disadvantage that the ion conductivity of the solid electrolyte is very low and the interface resistance between the electrode and the solid electrolyte is very high, so that the output characteristics cannot be expected at room temperature. For the reasons described above, such a battery has not been practically used industrially.

Accordingly, an object of the present invention is to provide a high energy density secondary battery employing a silicon compound, which is a powdery sintered body, as a positive electrode and a negative electrode and having an ionic polymer electrolyte.

Another problem to be solved by the present invention is a solution wet coating method that greatly improves the shortcomings of the vacuum deposition method, and has a high energy and high output characteristics that greatly improved the interface characteristics of the electrode and the polymer electrolyte separator using an ionic liquid It is to provide a method for manufacturing a secondary battery.

In order to solve the above problems, according to an aspect of the present invention,

Comprising a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and an ionic liquid impregnated in the separator, wherein the positive electrode and the negative electrode each comprises a silicon compound and a binder which is a powdery sintered body, the separator is hydrogen ion A secondary battery, which is a polymer electrolyte separator made of a conductive polymer, is provided.

The silicon compound may be selected from the group consisting of silicon carbide, silicon nitride, silicon oxide, and single crystal silicon.

The binder may be a hydrogen ion conductive polymer.

The ionic liquid is formed by the combination between the positive and negative ions, the cations are alkyl ammonium, and imidazolium, pyrrole iridium, at least one element selected from the group consisting of such as piperidinium, wherein the anion is BF ₄ ^-, PF ^{_{6 -, SbF 6 -, NO}} 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO 2) 3 C -, CF ^{_{3 CO 2 -, C 3 F}} 7 CO 2 -, CH 3 CO 2 -, and (CN) ₂ N ^- may be at least one selected from the group consisting of.

In addition, according to another aspect of the present invention,

Preparing a positive electrode by forming a positive electrode active material layer on a current collector using a positive electrode forming slurry including a positive electrode active material, a binder, and a solvent;

Preparing a negative electrode by forming a negative electrode active material layer on a current collector using a negative electrode forming slurry including a negative electrode active material, a binder, and a solvent;

Preparing an electrode assembly by inserting a separator between the positive electrode and the negative electrode; And

And placing the electrode assembly in a case and injecting an ionic liquid, wherein the anode and the cathode each include a silicon compound and a binder which are powdery sintered bodies, and the separator is an electrolyte separator made of a hydrogen ion conductive polymer. A method for producing a battery is provided.

Therefore, according to one embodiment of the present invention, by using a silicon compound, which is a powdery sintered body, as an electrode material, there is an advantage in that the secondary battery can be manufactured in an environment-friendly and solution process.

In addition, in the present invention, by using the polymer electrolyte containing the ionic liquid, the interfacial resistance between the electrode and the solid polymer electrolyte is significantly low, thereby providing an excellent output characteristic and greatly improving the safety of the battery even at a high temperature.

Furthermore, in the present invention, by using the solution wet coating process in manufacturing the electrode, it is possible to increase the density by controlling the thickness of the electrode as compared to the vacuum deposition process and has a great advantage in cost reduction.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical spirit of the present invention, the present invention is limited to the matters described in such drawings. It should not be construed as limited.

1 is a SEM image of the surface of a positive electrode (a) and a negative electrode (b) of a secondary battery according to an embodiment of the present invention.

2 shows a discharge curve according to the rate of the secondary battery according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to one aspect of the invention,

A positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and an ionic liquid impregnated in the separator, wherein the positive electrode and the negative electrode each comprise a silicon compound and a binder which is a powdery sintered body, the separator is hydrogen ion A secondary battery, which is a polymer electrolyte separator made of a conductive polymer, is provided.

As described above, when the silicon compound is formed of an electrode material such as a positive electrode and a negative electrode, manufacturing cost is greatly reduced compared to lithium used as an electrode material of a conventional lithium secondary battery, and it is very friendly to the environment, causing environmental pollution. There is an advantage that does not.

The said silicon compound consists of a powdery sintered compact. On the other hand, the electrode formed by simply vacuum deposition using a silicon compound is composed of only a single crystal of the silicon compound is limited that the filler or binder is mixed in order to impart additional properties. However, when an electrode is manufactured by using a wet process in the form of a powdery sintered compact with a silicon compound as an electrode material, as in an embodiment of the present invention, a multilayer electrode active material layer can be formed, thereby increasing the packing density of the electrode active material. As a result, the capacity per unit volume of the battery can be increased.

The sintered compact of the silicon compound is mixed with a silicon compound alone or with a silicon compound and an organic compound which generates carbon, nitrogen or the like by heating, which is heated to 1,000 ° C. in an inert atmosphere such as argon gas and allowed to cool to room temperature, Thereafter, the obtained mass may be pulverized with a ball mill in an inert atmosphere to prepare a powder having a predetermined average particle diameter.

In mixing to obtain a sintered body of the silicon compound, for the purpose of selectively mixing the silicon compound and the organic compound more homogeneously, a mixture of the silicon compound and the organic compound and the like may be cured and a mixed solid may be prepared. . As a method of such hardening, the method of bridge | crosslinking by heating, the method of hardening with a curing catalyst, and the method by an electron beam or a radiation are mentioned.

In mixing for obtaining the sintered compact of the silicon compound, known mixing means, for example, a mixer, a planetary ball mill, or the like is used. Moreover, as mixing time, 10 to 30 hours are preferable and 16 to 24 hours are more preferable. From the point of obtaining a high purity silicon compound sintered compact, the synthetic resin which does not contain a metal as much as possible can be used as a material, such as a mixer and a planetary ball mill.

The mixed solid material can be heated for the purpose of improving handleability, removing volatile gas or water, and the like. The heating is preferably performed for 30 to 120 minutes at 650 to 1,000 ° C in a non-oxidizing atmosphere such as nitrogen or argon.

In firing to obtain a sintered body of the silicon compound, the mixture (or mixed solids) is fired in a non-oxidizing atmosphere, and the conditions such as firing time and firing temperature are determined by the particle size of the sintered body powder of the desired silicon compound. Since it is different, although it is not limited to specific conditions, In order to make purity of the sintered compact of the silicon compound obtained, it can carry out at 1,350-2,100 degreeC, or 1,600-2,000 degreeC in non-oxidizing atmospheres, such as argon, Furthermore, it is non-oxidizing property Heat treatment may be performed at 2,000 to 2,100 ° C. for 5 to 20 minutes in an atmosphere.

Examples of such silicon compounds may be selected from the group consisting of silicon carbide, silicon nitride, silicon oxide, and single crystal silicon.

At this time, for example, in order to manufacture the sintered compact powder of silicon carbide, there is no restriction | limiting in particular as an organic compound which generate | occur | produces carbon by heating, high residual carbon ratio, polymerization and crosslinking according to presence of a catalyst and / or heating. An organic compound can be used. In particular, examples of the organic compound include monomers and prepolymers of resins such as phenol resins, furan resins, polyimides, polyurethanes, and polyvinyl alcohols, and liquid organic compounds such as cellulose, sucrose, pitch, and tar. Can be. These organic compounds may be used individually by 1 type, and may use 2 or more types together.

In addition, as the organic compound mixed to prepare the sintered compact powder of silicon nitride, any compound that generates nitrogen by heating can be used without limitation, for example, a polyimide resin and its precursor, hexamethylenetramine, ammonia, Various amines, such as triethylamine, are mentioned.

In the secondary battery according to an embodiment of the present invention, a compound based on SiC, which is the most stable of silicon carbide, may be employed as a cathode, and a compound based on Si ₃ N ₄ , which is the most stable of silicon nitride, is used as a cathode. It can be adopted.

Since the oxidation number of silicon tends to change more easily than carbon, and tetravalent is the next stable state in silicon, the following chemical reaction is performed at the time of charge and discharge by the positive electrode.

(One)

In the cathode, silicon nitride is Si ₂ N _{3 which} is next stable by changing silicon from tetravalent to trivalent and nitrogen from trivalent to divalent from the most stable Si ₃ N ₄ . When the compound is changed into a compound state and charged and discharged by the negative electrode, the following chemical formula is established.

(2)

The secondary battery made as above will have a charge and discharge mechanism as shown in equations (1) and (2). When SiC and Si ₃ N ₄ are charged, they form holes of Si ⁺ and Si ^-on each surface, and the counter ions are charged while maintaining their electrochemical neutrality on the surface of the formed holes. When discharging, reactions occur in opposite directions and the reactions are reciprocally circulated to complete a structure capable of charging and discharging energy.

In addition, in order to facilitate and smoothly promote charge and discharge associated with the production of silicon ions (Si ⁺ and Si ⁻ ), the silicon compound is not a complete crystal structure, but includes an amorphous structure. It is preferable that it is a form to make. Therefore, the silicon compound is crystallized to 60% or less containing amorphous can be applied.

The particle size of the silicon compound powder is not particularly limited, but a high-density sintered body is obtained, controlled to have an appropriate contact area with the electrolyte, and for the reason of handling of the powder, raw material price and uniformity during electrode production, for example, 20 μm. Hereinafter, or powders of average particle diameters in the range of 20 nm to 20 μm, or in the range of 300 nm to 5 μm, may be used.

The silicon compound employed in the positive electrode and the negative electrode of the secondary battery according to an embodiment of the present invention has the form of a powdery sintered body as described above, for example, a binder, a solvent, and a conductive agent, if necessary, in such a silicon compound. After mixing and stirring the dispersing agent to prepare a slurry, it can be applied to the current collector and compressed to produce an electrode.

In this case, the binder included in each of the positive electrode and the negative electrode may be a hydrogen ion conductive polymer.

The hydrogen ion conductive polymer may be, for example, a polymer having one or more cation exchange groups selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, and derivatives thereof in the side chain.

Specific examples thereof include polyacrylamide polymers, benzimidazole polymers, polyimide polymers, polyetherimide polymers, polyphenylene sulfide polymers, polysulfone polymers, polyether sulfone polymers, and polyether ketones. It may be one or more selected from the group consisting of a polymer, a polyether-etherketone-based polymer and a polyphenylquinoxaline-based polymer, but is not limited thereto.

Among these, Nafion ^® and poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) which are trade names of polymers in which sulfonic acid groups are introduced into the skeleton of polytetrafluoroethylene are used alone or in combination thereof. Can be used.

The binder may further include a binder used for a positive electrode and / or a negative electrode of a conventional secondary battery, in addition to a hydrogen ion conductive polymer. Examples of such a binder include vinylidene fluoride-hexafluoropropylene copolymer (PVDF- co-HFP), polyvinylidenefluoride, polyacrylonitrile, polymethylmethacrylate, and the like, various kinds of binder polymers may be used. The solvent used to prepare the composition for forming the positive electrode and the negative electrode is not particularly limited as long as it is commonly used, for example, N-methyl-2-pyrrolidone (NMP, N-methyl pyrrolidone) may be applied.

In this case, the content of the binder may be 2 to 20 parts by weight, or 3 to 10 parts by weight with respect to 100 parts by weight of the silicon compound included in the positive electrode or the negative electrode, and when the content range is satisfied, the silicon compound is positive and negative electrodes In order to form a strong bond to each other to prevent the detachment during operation of the secondary battery, and also serves as a bridge (bridge) between the electrolyte and the positive electrode or the negative electrode to significantly improve the transport and passage characteristics of hydrogen ions. Can be.

In addition, the positive electrode and the negative electrode may each independently include a conductive agent. Such conductive agents include carbon black, super-P, acetylene black, fine graphite powder, carbon nanotubes (CNT), whiskers, carbon fibers, and vapor grown carbon fibers (VGCF). At least one selected from the group consisting of) can be used.

The content of the conductive agent may be 1 to 20 parts by weight, or 3 to 10 parts by weight with respect to 100 parts by weight of the silicon compound contained in the positive electrode or the negative electrode, and when the content range is satisfied, the effect of the addition of the conductive material is exerted. In addition, it is possible to prevent the problem of lowering the high-capacity characteristics of the electrode by excessive addition, and when there is little conductive agent, sufficient conductivity between active materials cannot be secured, thereby increasing internal resistance and lowering power density.

As the current collector of the electrode active material, any electron conductor that does not adversely affect the battery configured can be used. For example, as the current collector for positive electrode, in addition to aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer, conductive glass, etc., the surface of aluminum or copper may be carbon, for the purpose of improving adhesion, conductivity, oxidation resistance, and the like. It is possible to use the thing processed with nickel, titanium, silver, etc. As the negative electrode current collector, copper, stainless steel, nickel, aluminum, titanium, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc., and other surfaces such as copper for the purpose of improving adhesion, conductivity and oxidation resistance. It is possible to use those treated with carbon, nickel, titanium or silver.

The separator of the present invention is a polymer electrolyte separator composed of a hydrogen ion conductive polymer, and serves as a separator for separating the positive electrode and the negative electrode, while providing a passage for ions, and during long-term repetitive operation at a high temperature of 80 ° C. or higher. It should not cause any degradation in performance and has excellent thermal, physical and chemical stability even in high temperature and strong acid environment.

The hydrogen ion conductive polymer may be used without limitation as long as it is applicable as the hydrogen ion conductive polymer described in the binder for forming the anode and the cathode. That is, polyacrylamide-based polymers, benzimidazole-based polymers, polyimide-based polymers, polyetherimide-based polymers, and polyphenylene sulfides, including Nafion-based polymers having sulfonic acid groups introduced into the backbone of polytetrafluoroethylene. Sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, and the like in polyolefins, polysulfone polymers, polyethersulfone polymers, polyetherketone polymers, polyether-etherketone polymers and polyphenylquinoxaline polymers One or more cation exchanger-introduced ionomer-type hydrocarbon polymers selected from the group consisting of derivatives may be applied, and these may be used alone or in combination of two or more thereof.

When the polymer electrolyte separator includes two or more hydrogen ion conductive polymers, polytetrafluoroethylene having a sulfonic acid group introduced therein, such as Nafion, is added to the total weight of the membrane in order to improve ion conductivity and mechanical properties of the polymer electrolyte separator. It may contain more than%. Less than 1% does not affect the improvement of mechanical properties and ion conductivity.

As the nonaqueous electrolyte of the secondary battery according to the exemplary embodiment of the present invention, an ionic liquid is used. The ionic liquids are ionic salts or molten salts consisting of cations and anions. An ionic compound composed of a cation and a non-metal anion, such as salt, is usually dissolved at a high temperature of 800 ° C. or higher, whereas an ionic salt existing as a liquid at a temperature of 100 ° C. or lower is called an ionic liquid. In particular, the ionic liquid present as a liquid at room temperature is referred to as room temperature ionic liquid (RTIL). Ionic liquids are nonvolatile, nontoxic, nonflammable, have excellent thermal stability and ionic conductivity. In addition, due to its high polarity, inorganic and organometallic compounds are well dissolved and have a unique characteristic of being present as a liquid in a wide temperature range, and thus are widely applied in a wide range of chemical fields such as catalysts, separations, and electrochemistry.

Since the secondary battery according to one embodiment of the present invention contains such an ionic liquid, the high temperature stability is greatly improved, and since the ionic liquid has excellent thermal stability and excellent ionic conductivity, the secondary battery obtained is stable. It becomes excellent, has high performance even at high rates of charge and discharge, and can obtain a battery of high energy density and high voltage. That is, the ionic liquid is absorbed by the polymer chain and acts as a plasticizer without degrading mechanical properties by the intermolecular forces of the ionic liquid and the polymer main chain, thereby making the polymer film flexible and increasing ion carriers to increase ion conductivity. It greatly improves the action. Moreover, this has the advantage of significantly reducing the interfacial resistance between the polymer film and the electrode to enable high output characteristics.

Such ionic liquids are formed from a combination of anions and cations.

The anions are _{^{BF 4 -, PF 6 -,}} SbF 6 -, NO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF ^{_{3 SO 2) 3 C -,}} CF 3 CO 2 -, C 3 F 7 CO 2 - , and the like _{^{-, CH 3 CO 2 -,}} (CN) 2 N. The said anion can contain 2 or more types.

Specifically, the anion is bis (perfluoroethylsulfonyl) imide, bis (trifluoromethylsulfonyl) imide, tris (trifluoromethylsulfonylmethide), trifluoromethanesulfonimide, Trifluoromethylsulfonimide, trifluoromethylsulfonate, tris (pentafluoroethyl) trifluoro phosphate, bis (trifluoromethylsulfonyl) imide, tetrafluoroborate, hexafluorophosphate, and It may be an anion of a compound selected from the group consisting of a combination of these.

The cation combined with the anion is not particularly limited, but may be a cation which forms an ionic liquid having a melting point of 50 ° C. or less. If the melting point exceeds 50 ° C., the resistance of the electrolyte separator rapidly increases, resulting in battery characteristic problems or discharge. This is because the capacity may be reduced. As the cation, any one of N, P, S, O, C, Si, or a compound containing two or more elements in the structure and having a chain structure or a five-membered or six-membered ring as a skeleton may be used. have. Specific examples of cyclic structures such as five-membered rings and six-membered rings include furan, thiophene, pyrrole, pyridine, oxazole, isoxazole, and thiazole. (thiazole), isothiazole, furazan, imidazole, pyrazole, pyrazine, pyrimidine, pyridazine, pyrrolidine ( heteromonocyclic compounds such as pyrrolidine and piperidine, benzofuran, isobenzofuran, indole, isoindole, indolizine, And condensed heterocyclic compounds such as carbazole.

Among the above cations, in particular, a chain structure or a ring structure compound containing a nitrogen element is industrially inexpensive and has an advantage of being chemically and electrochemically stable. Examples of the cation containing a nitrogen element include alkylammonium such as triethylammonium, imidazolium such as 1-ethyl-3-methyl imidazolium and 1-butyl-3-methyl imidazolium, and 1-methyl- And piperidinium such as pyrrolidinium such as 1-propyl pyrrolidinium and methyl propyl piperidinium.

The content of the ionic liquid may be about 0.05 to 30% by weight, or 0.1 to 5% by weight based on the total weight of the polymer electrolyte separator. When the content range of the ionic liquid is satisfied, the resistance due to the decrease in the ionic conductivity becomes too large, or the disadvantage that the life characteristics of the battery decreases due to the excess of salt can be prevented.

Referring to the secondary battery manufacturing method according to an aspect of the present invention.

First, a positive electrode active material layer is formed on a current collector using a positive electrode forming slurry containing a positive electrode active material, a binder, and a solvent to prepare a positive electrode, and a negative electrode forming slurry including a negative electrode active material, a binder, and a solvent is used. To form a negative electrode active material layer on the current collector to prepare a negative electrode.

The positive electrode active material, the negative electrode active material, the binder, and the solvent used are as described above, and optionally, the slurry for forming a positive electrode and the slurry for forming a negative electrode may each independently further include a conductive agent.

Thereafter, a separator is inserted between the prepared positive and negative electrodes to prepare an electrode assembly. As the separator, an electrolyte separator made of a hydrogen ion conductive polymer is applied as described above. That is, the separator may be prepared by forming a film using a polymer capable of conducting hydrogen ions, and drying the film.

Next, the prepared electrode assembly is placed in a case and an ionic liquid is injected. That is, a step of impregnating the ionic liquid in order to maximize the ionic conductivity and to reduce the interface resistance with the electrode in the dry solid separator prepared in the electrode assembly previously provided in the electrode assembly.

According to an embodiment of the present invention manufactured as described above, a secondary battery having an environmentally friendly and high energy density may be widely applied to various industrial fields, that is, a mobile communication device, an electric energy storage device, and an electric vehicle power source as an energy storage battery. .

Hereinafter, the present invention will be described in more detail with reference to specific test examples of the present invention. The following examples are merely provided to explain the present invention in more detail, whereby the technical scope of the present invention is not limited.

EXAMPLE

Silicon carbide was used as the positive electrode active material and silicon nitride was used as the active material of the negative electrode. Vapor-grown carbon fibers (VGCF, Showa, Denko K.K., Japan) were used as the conductive agent, and poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS, Aldrich) was used as the binder. In order to prepare a slurry for forming the electrode, 50 mg of PAMPS was added to 4 mL of NMP using N-methyl-2-pyrrolidone (NMP, Aldrich) as a solvent and stirred for 3 hours. After mixing the positive electrode active material and the conductive agent and the negative electrode active material and the conductive agent in a weight ratio of 8: 1 with a mortar and mortar, 45 mg were obtained, and the mixture was stirred in a solution containing NMP and PAMPS for at least 12 hours. I let you. The stirred anode forming slurry is coated on an aluminum current collector having a size of 2 cm x 2 cm, and used for forming a cathode. The slurry was coated on a 2.2 cm x 2.2 cm sized copper current collector, dried at room temperature for 36 hours, and then vacuum dried at 40 ° C. for at least 12 hours to prepare a positive electrode and a negative electrode. The positive electrode and the negative electrode thus obtained were observed in an electron micrograph and shown in FIG. 1. ((a) silicon carbide anode, (b) silicon nitride anode)

To prepare a polymer electrolyte membrane, Nafion ^® (perfluorinated ion-exchange resin, Aldrich) and PAMPS were mixed at a weight ratio of 3: 1 and stirred for 6 hours. 2 mL of the stirred solution was injected into a forming mold having a size of 3 cm x 3 cm, dried at room temperature for 72 hours, and vacuum dried at 40 ° C. for 24 hours to prepare a polymer electrolyte membrane having a thickness of 15 μm.

 The finished positive and negative electrodes and the polymer electrolyte separator were fabricated into an aluminum pouch full cell in an argon glove box. Into the polymer electrolyte membrane, 30 μL of an ionic liquid of 1-ethyl-3-methyl imidazolium bis (trifluoromethane sulfonyl) imide (EMITFSI, C-tri Co., Korea) Sprayed to soak well. The secondary battery was manufactured by sealing the outside of the battery stacked in the form of a cathode / polymer electrolyte separator / cathode using an aluminum pouch.

Evaluation of discharge capacity characteristics of secondary battery

The discharge capacity of the secondary battery manufactured in Example was evaluated and shown in FIG. 2.

Referring to the discharge curve of Figure 2, it can be seen that excellent discharge characteristics from 4.5 V to 3.5 V, it exhibits a high discharge capacity of 312 mAh / g at 0.1 C.

This value is about 30% higher than that of a conventional lithium ion battery, and the secondary battery manufactured in the embodiment of the present invention employs a silicon compound, which is a powdery sintered body, as an electrode material to form an electrode, thereby increasing energy density, and hydrogen ion. By providing a conductive polymer as a polymer electrolyte separator, the ion conductivity is greatly improved, which is interpreted as a result showing high capacity characteristics.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (14)

1. An anode, a cathode, a separator provided between the anode and the cathode, and an ionic liquid impregnated in the separator,

   The positive electrode and the negative electrode each contain a silicon compound and a binder which is a powdery sintered body,

   The secondary battery is a solid electrolyte separator made of a hydrogen ion conductive polymer.
2. The method of claim 1,

   And the silicon compound is selected from the group consisting of silicon carbide, silicon nitride, silicon oxide and single crystal silicon.
3. The method of claim 1,

   Secondary battery characterized in that the silicon compound is crystallized to 60% or less containing amorphous.
4. The method of claim 1,

   The secondary battery, characterized in that the average particle diameter of the silicon compound is 20 ㎛ or less.
5. The method of claim 1,

   Secondary battery, characterized in that the positive electrode and the negative electrode each independently further comprises a conductive agent.
6. The method of claim 5,

   The conductive agent may be carbon black, super-P, acetylene black, fine graphite powder, carbon nanotube (CNT), whisker, carbon fiber, vapor grown carbon fiber (VGCF). Secondary battery, characterized in that at least one selected from the group consisting of.
7. The method of claim 1,

   Secondary battery, characterized in that the binder is a hydrogen ion conductive polymer.
8. The method according to claim 1 or 7,

   The hydrogen ion conductive polymer is one or a mixture of two or more selected from the group consisting of a polymer having at least one cation exchange group selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups and derivatives thereof in the side chain Secondary battery, characterized in that.
9. The method of claim 1,

   The ionic liquid is formed by the combination between the positive and negative ions, the cations are alkyl ammonium, and imidazolium, pyrrole iridium, at least one element selected from the group consisting of piperidinium, wherein the anion BF ₄ ^-, PF _{6 ^{-, SbF 6 -, NO 3}} -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO 2) 3 C -, CF 3 ^{_{CO 2 -, C 3 F 7}} CO 2 -, CH 3 CO 2 -, and (CN) ₂ N ^- secondary battery, characterized in that at least one member selected from the group consisting of.
10. The method of claim 1,

    The secondary battery, characterized in that the content of the ionic liquid is 0.05 to 30% by weight based on the total weight of the polymer electrolyte separator.
11. Preparing a positive electrode by forming a positive electrode active material layer on a current collector using a positive electrode forming slurry including a positive electrode active material, a binder, and a solvent;

    Preparing a negative electrode by forming a negative electrode active material layer on a current collector using a negative electrode forming slurry including a negative electrode active material, a binder, and a solvent;

    Preparing an electrode assembly by inserting a separator between the positive electrode and the negative electrode; And

    Placing the electrode assembly in a case and injecting an ionic liquid;

    The method of manufacturing a secondary battery, wherein the positive electrode and the negative electrode each include a silicon compound and a binder, which are powdery sintered bodies, and the separator is an electrolyte separator made of a hydrogen ion conductive polymer.
12. The method of claim 11,

    The silicon compound is a method of manufacturing a secondary battery, characterized in that selected from the group consisting of silicon carbide, silicon nitride, silicon oxide, and single crystal silicon.
13. The method of claim 11,

    The method of manufacturing a secondary battery, wherein the positive electrode and the negative electrode each independently include a conductive agent.
14. The method of claim 13,

    The method of manufacturing a secondary battery, characterized in that the conductive agent is contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the silicon compound contained in the positive electrode or the negative electrode.

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