KR101655627B1 - Organic-inorganic complex solid polymer electrolytes membrane, manufacturing method thereof and all solid battery including thereof - Google Patents

Abstract

The present invention relates to an organic-inorganic composite solid electrolyte membrane, a method for producing the same, and an all-solid-state cell comprising the same. More particularly, the present invention relates to a solid- And the electrochemical stability and the ionic conductivity, mechanical properties, processability, and electrochemical stability of the solid electrolyte are improved compared to conventional solid electrolytes, and since the photo-crosslinkable polymer is distributed at the interface of the oxide solid electrolyte on the powder, Organic composite solid electrolyte membrane applicable to the present invention, a process for producing the same, and an all solid battery including the same.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic-inorganic composite solid electrolyte membrane, a method of manufacturing the same, and a pre-solid electrolyte battery including the same,

The present invention relates to an organic-inorganic composite solid electrolyte membrane, a method for producing the same, and an all-solid-state cell comprising the same. More particularly, the present invention relates to a solid- And the electrochemical stability and the ionic conductivity, mechanical properties, processability, and electrochemical stability of the solid electrolyte are improved compared to conventional solid electrolytes, and since the photo-crosslinkable polymer is distributed at the interface of the oxide solid electrolyte on the powder, Organic composite solid electrolyte membrane applicable to the present invention, a process for producing the same, and an all solid battery including the same.

A secondary cell is a cell in which chemical energy and electric energy are converted through oxidation and reduction chemistry to repeatedly charge and discharge. Generally, the battery includes four basic elements of an anode, a cathode, a separator, and an electrolyte. At this time, the positive electrode and the negative electrode are collectively referred to as electrodes, and among the constituent elements of the electrode material, a material that actually causes reaction is referred to as an active material. The electrode is composed of a composite material and a current collector. The composite material includes a cathode active material, and if necessary, the current collector is made of a material having electron conductivity such that a conductive material and a binder are added.

A typical lithium ion secondary battery uses an electrolyte including a liquid electrolyte and a liquid. However, liquid electrolytes are volatile, and there is a risk of explosion and thermal stability is also deteriorated.

On the other hand, an all solid state battery using a solid electrolyte has low explosion risk and excellent thermal stability. In addition, when a bi-polar plate is used, it is possible to form a high operating voltage by stacking the electrodes and making the series connection possible. In this case, the energy density can be higher than that of the parallel connection method of the cell in which the liquid electrolyte is applied have.

In order to produce such a pre-solid battery, a solid electrolyte for transferring lithium ions is necessarily required. Solid electrolytes are classified into organic (polymer) electrolytes and inorganic electrolytes. Inorganic electrolytes are classified into oxide electrolytes and sulfide electrolytes.

The polymer electrolyte is superior in stability to liquid electrolyte by hopping lithium ions in the molecular chain. However, in the case of a polymer containing no liquid, the ion conductivity at room temperature is 10 ^-7 to 10 ^-4 S / m Of the total. In addition, since the mechanical properties are poor, there is a disadvantage that it is unstable at a high voltage of 4 V or more.

Sulfide-based solid electrolyte is _{Li 2 SP 2 S 5, Thio} -LISICON, Li-MPS , and a variety of structures and components, such as known (M = Si, Ge, Sn ), 10 -3 ~ 10 -2 S / cm level It is reported to have a high ionic conductivity. However, the sulfide-based solid electrolyte reacts with moisture to generate poisonous H ₂ S gas, which can be used in an environment where moisture is removed, and is very dangerous when exposed to the atmosphere and has a disadvantage in that the ionic conductivity drops sharply. In addition, there is a disadvantage in that it is necessary to use a nonpolar solvent such as benzene, toluene, or xylene which is poisonous in the preparation of the slurry since it is stable to a nonpolar solvent and unstable to a polar solvent. In this case, the slurry properties also deteriorate.

The oxide-based solid electrolyte is an electrolyte containing oxygen such as LiPON, perovskite, garnet and glass ceramic, and has an ionic conductivity of 10 ^-5 to 10 ^-3 S / cm which is lower than that of the sulfide system Ion conductivity, but it is very excellent in moisture and stability compared to the sulfide solid electrolyte. However, the oxide-based solid electrolyte has a high grain boundary resistance, so an electrolyte membrane or a pellet that forms a necking between particles by sintering at a high temperature can be used. The high-temperature sintering at a high temperature of 900 to 1400 ° C There is a problem that the mass productivity is very poor to form a large-sized electrolyte membrane.

Conventional US 2013-0230778 discloses an electrolyte in which an oxide-based (garnet) solid electrolyte forms a porous body, and a polymer mixed with the liquid electrolyte is filled in the porous body to prevent leakage of the liquid electrolyte, However, there is a disadvantage that the liquid electrolyte still contains the explosion danger.

JP 2009-94029 discloses a solid electrolyte for an electrode in which an oxide-based inorganic electrolyte and a polymer electrolyte are mixed. However, it has disadvantages in that the oxide electrolyte is precipitated during the evaporation of the solvent and the uniformity of the film is lowered.

In addition, KR 2013-014224 discloses a solid polymer electrolyte comprising an organic solvent in which inorganic particles capable of preventing the leakage of a liquid electrolyte that transfers lithium ions to a polymer matrix of a network structure cured with a photo-crosslinking agent are distributed However, the ionic conductivity of the electrolyte can be lowered due to the inorganic particles having no ion conductivity, and the volatile organic liquid is still used.

In addition, a method of preparing a composite membrane by hot-pressing at 110 ° C after mixing a (LiAlTiP) xOy-type oxide solid electrolyte and a polyelectrolyte of PEO (poly ethylene oxide) -LiN (SO2CF2CF3) 2 with a ball mill [ Wang et al., Journal of power sources 112 (2002) p.209], but the method of applying heat and pressure has limitations in the continuous coating process and large-scale application. Depending on the pressure to be applied, There is a drawback that it is easy to exist.

In addition, a mixture of polyelectrolyte (PEO) -PPO (polypropylene oxide) -LiTFSI polymer dissolved in an ethanol solution was prepared as Li _{1 + x + y} Al _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (Y. Inda et al., Journal of power sources 174 (2007) p. 741), in which an electrolyte is mixed with an oxide solid electrolyte in the form of a solid electrolyte, and then the ethanol solvent is volatilized to volatilize the solvent. In the case of preparing the composite, the solvent used may dissolve the electrode material, and the oxide electrolyte having a high density is precipitated during the drying of the solvent.

As described above, since the PEO (poly ethylene oxide) polymer mixed with the lithium salt, which is usually used as the polymer electrolyte, exists in a solid state, it is possible to apply a method of applying heat to the oxide solid electrolyte and pressurizing it during the production thereof, , Followed by volatilization of the solvent. However, there have been problems such as the limitation of the continuous coating process and the large surface area, the dissolution of the electrode material, and the precipitation of the oxide solid electrolyte.

Accordingly, the present invention can improve the low ionic conductivity, mechanical properties, and electrochemical stability of a polymer electrolyte by preparing a solid electrolyte comprising a photo-crosslinkable polymer and an oxide-based solid electrolyte, Is distributed on the interface of the oxide-based solid electrolyte on the powder, so that a room temperature printing process can be applied without using a high-temperature sintering process used in the production of the oxide-based solid electrolyte membrane, and a sulfide-based solid electrolyte And thus it is possible to improve the stability and processability. Thus, the present invention has been completed.

Accordingly, an object of the present invention is to provide an organic-inorganic hybrid electrolyte membrane improved in ionic conductivity and electrochemical stability compared to conventional solid electrolytes.

Another object of the present invention is to provide a method for producing an organic / inorganic composite solid electrolyte membrane which can be directly printed on an electrode because no solvent is mixed.

It is still another object of the present invention to provide an all-solid-state cell including the organic-inorganic hybrid electrolyte membrane with improved electrochemical stability.

It is still another object of the present invention to provide a vehicle including the all-solid-state battery.

In order to solve the above problems, the present invention provides a photo-crosslinkable polymer mixed with a lithium salt; And an oxide solid electrolyte, wherein the photo-crosslinkable polymer is mixed and distributed in the oxide solid electrolyte. The present invention also provides an organic-inorganic hybrid electrolyte membrane.

The present invention also provides a method for preparing an electrolyte slurry, comprising the steps of: preparing an electrolyte slurry by mixing a photocrosslinking polymer mixed with a lithium salt and an oxide solid electrolyte; Casting the electrolyte slurry onto an electrode layer or substrate; And irradiating the cast electrolyte slurry with ultraviolet light to prepare a photocrosslinked organic / inorganic hybrid solid electrolyte membrane. The present invention also provides a method of manufacturing the organic / inorganic composite electrolyte membrane.

The present invention also provides a pre-solid battery comprising the organic-inorganic composite solid electrolyte membrane.

The present invention also provides a vehicle including the above all-solid-state battery.

The organic-inorganic hybrid electrolyte membrane according to the present invention has the following advantages.

1) A solid electrolyte that does not use liquid at all by mixing a photocrosslinking polymer mixed with a lithium salt to an oxide solid electrolyte. It improves mechanical properties and electrochemical stability compared to conventional polymer electrolytes, Thereby improving the ease of processing and flexibility.

2) The photocrosslinkable polymer exists as an oligomer-type liquid phase at the initial room temperature, so that the oxide solid electrolyte can be uniformly mixed without further solvent addition, and the solid polymer can be converted into a solid polymer immediately after the UV process to precipitate the oxide solid electrolyte And disperses it uniformly, thereby improving the ionic conductivity and increasing the charge / discharge efficiency.

3) There is an effect of preventing the problem that the active material is eluted from direct printing on the electrode coated with the positive electrode or the negative electrode mixture because the solvent is not mixed and minimizing pores generated in the solid electrolyte during drying of the solvent.

4) The photocrosslinking type polymer is distributed at the interface of the oxide solid electrolyte on the powder, so that it can be applied to the room temperature printing process.

1 is a cross-sectional view of an organic-inorganic hybrid electrolyte membrane according to the present invention.
FIG. 2 is a process diagram showing an example of a process for producing an organic-inorganic hybrid electrolyte membrane according to the present invention.
3 is a cross-sectional view of an all solid-state battery showing an example of a method of forming a stack of cells using the organic-inorganic hybrid electrolyte membrane according to the present invention.
4 is a graph showing the results of charge and discharge of the all-solid-state cell manufactured in Example 3 according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to one embodiment.

The organic-inorganic composite solid electrolyte membrane of the present invention comprises a photo-crosslinkable polymer mixed with a lithium salt; And an oxide solid electrolyte, wherein the photo-crosslinkable polymer is mixedly distributed in the oxide solid electrolyte.

The organic-inorganic hybrid electrolyte membrane has a photocrosslinking polymer in which the lithium salt is mixed at the interface of the oxide solid electrolyte. The photocrosslinking polymer and the oxide solid electrolyte both function to transfer lithium ions, There is an effect of improving the conductivity.

The lithium salt may be at least one selected from the group consisting of lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroantimonate (LiSbF ₆ ), lithium hexafluoroacetate (LiAsF ₆ ), lithium difluoromethane sulfonate _{(LiC 4 F 9 SO 3)} , lithium perchlorate (LiClO _4), lithium aluminate (LiAlO _2), lithium tetrachloro- aluminate (LiAlCl _4), lithium chloride (LiCl), lithium iodide (LiI), lithium bis oxalate reyito Borate (LiB (C ₂ O ₄ ) ₂ ), and lithium trifluoromethanesulfonylimide (LiTFSI), may be used alone or in combination of two or more.

The photo-crosslinkable polymer and the lithium salt may be prepared by mixing [EO] of the photo-crosslinkable polymer and [Li] of the lithium salt in an 8 to 12: 1 molar ratio. Specifically, if the content is out of the molar ratio of 8: 1, the mechanical properties of the membrane may deteriorate, and if the molar ratio exceeds 12: 1, the ion conductivity may decrease.

The photo-crosslinkable polymer may be one or more selected from the group consisting of polyethylene oxide methacrylate (PEOMA), polyethylene glycol diacrylate and triethyleneglycol diacrylate Can be used.

The photocrosslinkable polymer is present in a liquid state in the form of an oligomer having a low molecular weight at room temperature, and when irradiated with ultraviolet light, the oligomer may be cured into a solid state of the polymer by photo-crosslinking. The phase change from the liquid phase to the solid phase caused by the ultraviolet irradiation is easier than the process in which the conventional polymer solid electrolyte is dissolved in the solvent to prepare the slurry and then the solvent is evaporated. The solvent is not used, The precipitation phenomenon of the oxide solid electrolyte can be prevented, and the internal pore of the solid electrolyte membrane can be minimized.

The photo-crosslinking polymer may be mixed with a photo-initiator to accelerate photo-crosslinking. The photoinitiator may be at least one selected from the group consisting of HMPP (2-hydroxy-2-methyl-1-phenyl-1-propanone), benzophenone and thioxanthone.

The oxide solid electrolyte may include lithium oxide (LiPON), garnet, perovskite, NASICON (Na-super ionic conductor), and oxides, And a solid electrolyte capable of dissolving the solid electrolyte. The oxide solid electrolyte is in powder form and its ionic conductivity is 10 ^-3 to 10 ^-5 S / cm, which is superior to the polymer electrolyte and stable in the atmosphere. Specifically, the LiPON system is a Li ₃ PO ₄ structure containing nitrogen (N) The garnet system is Li _{7 - y} La _{3 - x} A _x Zr _{2 -y} M _y O ₁₂ where x is 0? X? 3, y is 0? Y? 2, A is Y, Nd , Sm, and Gd, and M is Nb or Ta). The perovskite system may be a Li _{0 .5-3 x} La _{0 .5 + x} TiO ₃ wherein x is _{0 ? X?} 0.15, and the NASICON (Na-super ionic conductor) system is _{Li 1 + x Al x Ti 2} -x (PO 4) 3 ( where, x is the 0≤x≤3) or _{Li 1 + x Al x Ge 2} -x (PO 4) 3 ( where, x Is 0? X? 3).

The oxide solid electrolyte may have an average particle size of 10 nm to 30 탆. Specifically, when the particle size is smaller than 10 nm, dispersion is difficult. When the particle size is larger than 30 m, it is difficult to reduce the thickness of the solid electrolyte membrane.

The content of the oxide solid electrolyte may be 20 to 60% by weight based on the total organic / inorganic hybrid solid electrolyte membrane. Specifically, when the content of the oxide solid electrolyte is less than 20% by weight, it may be difficult to improve the properties of the polymer electrolyte, and when it is more than 60% by weight, the interface resistance of the composite electrolyte may increase. And preferably 30 to 55% by weight. More preferably 40 to 50% by weight.

The organic-inorganic composite solid electrolyte membrane may be one in which a photo-crosslinking polymer in which the lithium salt is mixed is dispersed by cross-linking at the interface of the oxide solid electrolyte. Specifically, the lithium salt and the photocrosslinking polymer are mixed and crosslinked in the polymer. When the photo-crosslinkable polymer in the form of an oligomer having a low initial molecular weight and in the form of a liquid is subjected to ultraviolet light, the double bond in the photo-crosslinkable polymer is broken and crosslinks with the neighboring oligomer. It can be a polymer.

The inorganic-organic composite solid electrolyte membrane may have a thickness of 1 to 100 탆. Specifically, if the thickness of the organic-inorganic hybrid electrolyte membrane is less than 1 탆, the processability is difficult. If the thickness is more than 100 탆, the resistance of the electrolyte may be increased.

The present invention also provides a method for preparing an organic-inorganic hybrid electrolyte membrane, comprising: preparing an electrolyte slurry by mixing a photocrosslinking polymer mixed with a lithium salt and an oxide solid electrolyte; Casting the electrolyte slurry onto an electrode layer or substrate; And irradiating the cast electrolyte slurry with ultraviolet light to prepare a photocrosslinked organic / inorganic hybrid solid electrolyte membrane.

In the step of preparing the electrolyte slurry, it is preferable to stir at room temperature to 100 ° C for 30 minutes to 10 hours, and the organic-inorganic composite solid electrolyte membrane cast on the electrode layer may have a thickness of 1 to 100 μm.

The electrode layer may be a cathode layer or a cathode layer. Specifically, the anode layer is composed of a current collector and a positive electrode composite material, and the positive electrode composite material is formed on the surface of the current collector and may contain at least a positive electrode active material. As the cathode active material, for example, LiCoO2, LiNi1 / 3Co1 / 3Mn1 / 3O2, LiMnO2, LiVO2, LiCrO2, Li2NiMn3O8, LiFePO4 and LiCoPO4, LiNiO2 can be used.

The anode layer may contain at least one selected from the group consisting of a conductive material, a solid electrolyte and a binder. The conductive material may be contained to improve the electronic conductivity in the electrode. For example, ketjen black, acetylene black, carbon fiber, and graphene may be used. The solid electrolyte can improve the ion conductivity in the electrode. As the solid electrolyte, an oxide solid electrolyte, a sulfide solid electrolyte, or a polymer electrolyte may be used as described above. The binder can improve the binding force in the electrode. Examples of the binder include rubber-based or acetonitrile-containing polymers such as polyvinylidene fluoride (PVDF), nitrile butadiene rubber (NBR), and styrene butadiene rubber (SBR).

The method for forming the anode layer is not particularly limited as long as it is a method capable of forming a positive electrode composite material on the surface of the current collector. For example, by pressurizing the materials constituting the positive electrode composite material. More preferably, the slurry containing the positive electrode composite material and the solvent can be prepared, applied directly on the current collector, and dried.

The negative electrode layer used in the present invention is composed of a current collector and a negative electrode composite material. The negative electrode composite material is coated on the current collector, and is disposed on the opposite side of the positive electrode layer with the solid electrolyte layer interposed therebetween. If necessary, the negative electrode layer may contain at least one selected from the group consisting of a conductive material, a solid electrolyte and a binder. Specifically, examples of the negative electrode active material include a carbon material selected from the group consisting of artificial graphite, natural graphite, soft carbon, and hard carbon, or a metal active material selected from the group consisting of Al, Sn, Si, Mg, May be used. When Li is used as a negative electrode, lithium foil having a thickness of 10 to 1000 mu m may be attached to the current collector. In addition, when the anode active material is used, the anode active material layer can be formed in the same manner as the above-described anode layer forming method, and thus can be omitted here.

In the step of casting the electrolyte slurry, it is preferable to perform the atmospheric or dehumidified atmosphere, and the electrolyte slurry may be cast on the electrode layer or the substrate. The electrolyte slurry can be directly printed on the electrode layer coated with the positive electrode or the negative electrode mixture since the solvent is not mixed and the electrode material is not eluted as a solvent.

In the step of irradiating the cast electrolyte slurry with ultraviolet light, the ultraviolet light may be irradiated for a few seconds to several tens of minutes to cure the applied photo-crosslinkable polymer. Specifically, the photocrosslinking polymer present in a liquid state at room temperature may be converted into a solid polymer by cross-linking of the polymer directly after the ultraviolet (UV) irradiation process, thereby preventing precipitation of the oxide solid electrolyte.

1 is a cross-sectional view of an organic-inorganic hybrid electrolyte membrane according to the present invention. FIG. 1 shows a structure in which a positive electrode or a negative electrode material is laminated on a current collector, and an organic / inorganic composite electrolyte membrane is formed thereon. It can also be seen that the oxide solid electrolyte was cured in a state where the oxide solid electrolyte was uniformly distributed on the photo-crosslinkable polymer electrolyte without precipitating on the organic-inorganic hybrid electrolyte membrane.

FIG. 2 is a process diagram showing an example of a process for producing an organic-inorganic hybrid electrolyte membrane according to the present invention. FIG. 2 shows a process of applying an electrode slurry coating process 100 on a current collector, followed by an electrode drying process 200, and then performing an inorganic hybrid solid electrolyte slurry coating process 300. Followed by an ultraviolet (UV) curing process 400 to continuously form the organic / inorganic composite solid electrolyte membrane.

On the other hand, the pre-solid battery of the present invention includes the above-mentioned organic-inorganic hybrid electrolyte membrane.

The pre-solid battery does not include a liquid electrolyte as compared with conventional batteries, and thus has excellent heat resistance and atmospheric stability. 3 is a cross-sectional view of an all solid-state battery showing an example of a method of forming a stack of cells using the organic-inorganic hybrid electrolyte membrane according to the present invention. 3 (a), the battery is formed by casting an organic-inorganic composite solid electrolyte slurry on one of an anode and a cathode, forming a solid electrolyte membrane by ultraviolet curing, and bonding the opposite electrode thereon to form an all- Show the structure. In this case, the interface resistance between the solid electrolyte and the electrode can be reduced to improve the battery characteristics.

3 (b) shows a method of casting an inorganic-organic composite solid electrolyte slurry on a stainless steel (SUS) or a Teflon substrate and UV-curing it to form a solid electrolyte membrane, And a cathode layer and a cathode layer joined to the upper and lower surfaces of the solid electrolyte membrane manufactured after the formation of the solid electrolyte membrane. In this case, since the electrode material does not undergo ultraviolet curing, there is an advantage that the denaturation of the electrode material can be minimized. In addition, when the electrode layer is attached and then heated or pressurized by a press machine as required, adhesion between the electrode and the solid electrolyte can be improved.

On the other hand, the present invention includes a vehicle including the above all-solid-state battery.

Therefore, the organic-inorganic composite solid electrolyte membrane according to the present invention is a whole solid electrolyte which does not use a liquid at all by mixing a photocrosslinking polymer mixed with a lithium salt into an oxide solid electrolyte, and is superior in mechanical properties and electrochemical stability to conventional polymer electrolytes And has the effect of improving the ease and flexibility of the film forming process as compared with the conventional oxide electrolyte.

In addition, since it does not emit toxic substances when exposed to moisture in the atmosphere, it is safer than conventional lithium ion batteries or sulfide-based solid electrolytes, and the photocrosslinking polymer exists in an oligomer-like liquid phase at an initial room temperature. And can be uniformly mixed. By changing to a solid state polymer immediately after an ultraviolet (UV) irradiation process, precipitation of an oxide solid electrolyte can be prevented, and uniform dispersion of the oxide solid electrolyte can be achieved, thereby improving ionic conductivity and increasing charge / have.

In addition, since the solvent is not mixed, the problem that the active material is eluted from direct printing on the electrode coated with the positive electrode or the negative electrode mixture is prevented, and direct printing is possible, and pore generated in the solid electrolyte is minimized when the solvent is dried. Also, since the photo-crosslinkable polymer is distributed at the interface of the oxide solid electrolyte on the powder, it can be applied to the room temperature printing process.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

Lithium salt (LiTFSI) was mixed with the PEOMA (Mn = 500, 10 EO repeating units) in a vial having a molar ratio of [E0] and [Li] of 10: 1, and the mixture was stirred for 1 hour. Then, 5 wt% of benzophenone was added to the mixture as a photoinitiator to prepare a photo-crosslinkable polymer solution. The polymer solution thus prepared was mixed with 30 wt% of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) powder to prepare an organic / inorganic composite solid electrolyte slurry.

The slurry thus prepared was coated on a disk-shaped stainless steel (SUS), irradiated with ultraviolet rays (UV), and cured to form an organic-inorganic hybrid electrolyte membrane having a thickness of 60 탆. Subsequently, stainless steel (SUS) was attached to the solid electrolyte membrane to prepare an all solid battery having an SUS / inorganic composite solid electrolyte membrane / SUS structure.

Example 2

The same procedure as in Example 1 was carried out except that 50% by weight of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) powder was mixed with the photo-crosslinkable polymer solution prepared in Example 1 to prepare an organic / inorganic composite solid electrolyte slurry. A solid electrolyte cell with a SUS / nonaqueous composite solid electrolyte membrane / SUS structure was fabricated.

Comparative Example 1

The same procedure as in Example 1 was carried out except that 70% by weight of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) powder was mixed with the photo-crosslinkable polymer solution prepared in Example 1 to prepare an organic / inorganic composite solid electrolyte slurry. A solid electrolyte cell with a SUS / nonaqueous composite solid electrolyte membrane / SUS structure was fabricated.

Comparative Example 2

PEO (polyethyleneoxide, Mn = 400000) was mixed with an acetonitrile solvent and a lithium salt (LiTFSI) was mixed at a weight ratio of 10: 1 to prepare a polymer electrolyte solution. The solid polymer concentration of the prepared polymer electrolyte solution was adjusted to 20% by weight and stirred at room temperature for one day. Then a mixture of the polymer electrolyte solution was 30% by weight of the garnet _{(Li 7 La 3 Zr 2 O} 12) to prepare a solid electrolyte slurry.

The prepared solid electrolyte slurry was applied to a disk-shaped stainless steel (SUS) in the same manner as in Example 1, and then cured to form a solid electrolyte membrane. Then, stainless steel (SUS) was attached to the solid electrolyte membrane to prepare a SUS / solid electrolyte membrane / SUS pre-solid battery.

Comparative Example 3

Except that 50% by weight of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) was added to the polymer electrolyte solution prepared in Comparative Example 3 to prepare a solid electrolyte slurry. SUS / Solid electrolyte membrane / SUS structure.

Comparative Example 4

Except that 70% by weight of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) was mixed with the polymer electrolyte solution prepared in Comparative Example 3 to prepare a solid electrolyte slurry. SUS / Solid electrolyte membrane / SUS structure.

Experimental Example 1: Evaluation of ionic conductivity

In order to evaluate ionic conductivities of all the solid-state batteries prepared in Examples 1 and 2 and Comparative Examples 1 to 6, an AC impedance analyzer was used to evaluate an AC voltage of 10 mV and a frequency range of 0.1 Hz to 20 Hz . The results are shown in Table 1 below.

LLZ (% by weight) Ion conductivity Example 1 2.1 * 10 ^-5 S / cm Example 2 2.6 * 10 ^-5 S / cm Comparative Example 1 2.7 * 10 ^-6 S / cm Comparative Example 2 7.3 * 10 ^-6 S / cm Comparative Example 3 7.1 * 10 ^-7 S / cm Comparative Example 4 7.3 * 10 ^-8 S / cm

According to the results shown in Table 1, in the case of Examples 1 and 2 in which a photocrosslinkable polymer (PEOMA) was applied and 30 and 50 wt% of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) It was confirmed that the ionic conductivity increased due to the uniformly dispersed oxide solid electrolyte.

On the contrary, in the case of Comparative Example 1 containing 70 wt% of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ), it was found that the grain boundary resistance between Garnet and Garnet was formed and the ion conductivity of the organic-inorganic composite solid electrolyte membrane dropped there was.

In addition, in the case of Comparative Examples 2 to 4 in which the PEO polymer was applied, it was confirmed that the ion conductivity as a whole was low, and the ion conductivity of the solid electrolyte membrane was steadily decreased as the garnet content was increased. This is because the drying process of evaporating the solvent during the process of forming the solid electrolyte membrane using the PEO polymer dissolved in the solvent is long and the ion conductivity of the membrane is decreased due to the formation of the garnet in the solid electrolyte film during the evaporation of the solvent Could know.

Example 3

(1) Preparation of anode layer

The anode layer can be produced by a conventional method. Specifically, NCM was used as a cathode active material, super C was used as a conductive material, and PVDF was used as a binder. A cathode slurry was prepared by mixing the above materials in an NMP solvent. The mixing was carried out at 5000 rpm for 10 minutes using a homomixer. The prepared positive electrode slurry was applied to an aluminum foil current collector and dried in a hot air oven maintained at a temperature of 110 DEG C for 2 hours to form a positive electrode layer.

(2) Preparation of organic-inorganic composite solid electrolyte slurry

Lithium salt (LiTFSI) was mixed in PEOMA (Mn = 500, EO repeating unit 10) at a weight ratio of 10: 1, and then stirred for 1 hour. Then, 5 wt% of benzophenone was added to the mixture as a photoinitiator to prepare a photo-crosslinkable polymer solution. The resulting polymer solution was mixed with 50 wt% of Garnet (Li ₇ La ₃ Zr ₂ O ₁₂ ) powder to prepare an organic / inorganic composite solid electrolyte slurry.

(3) Production of organic / inorganic composite solid electrolyte membrane

The organic-inorganic composite solid electrolyte slurry was coated on the positive electrode layer formed on the current collector. Then, ultraviolet (UV) light was irradiated twice for 2 minutes in order to cure it to form an organic-inorganic hybrid electrolyte membrane.

(4) Cell configuration

A composite solid electrolyte membrane of NCM / organic composite electrolyte / lithium metal structure was constructed by punching the organic / inorganic composite solid electrolyte membrane coated on the NCM anode with a diameter of 18 mm and using lithium metal as the cathode on the opposite side. The lithium metal had a thickness of 100 탆 and was punched with a diameter of 16 mm, and SUS was used as a current collector.

Experimental Example 2: Cell evaluation

Charge / discharge evaluation was carried out by a constant current application method in order to confirm the charging / discharging characteristics of the NCM / non-aqueous composite electrolyte / lithium metal structure all-solid battery manufactured in Example 3 above. Here, the applied current was 10 μA, and the voltage was subjected to charge / discharge evaluation for 7 times in the interval of 2.5 to 4.5 V, and the result is shown in FIG.

FIG. 4 is a graph showing the charge / discharge results of the all-solid-state cell manufactured in Example 3. FIG. As shown in FIG. 4, it was confirmed that the charging and discharging capacities were as high as 0.28 mAh and 0.12 mAh, respectively, as a result of one charge and discharge. It was found that the application of the organic / inorganic composite solid electrolyte membrane in which the oxide electrolyte was uniformly dispersed increased the ionic conductivity and was 50% higher than the discharge capacity of the conventional solid electrolyte.

Accordingly, the organic-inorganic composite solid electrolyte membrane according to the present invention can be used to uniformly mix the oxide solid electrolyte without addition of an additional solvent since the photo-crosslinkable polymer exists in an oligomer-like liquid state at an initial room temperature. It was confirmed that the solid electrolyte was converted into a solid state polymer to prevent precipitation of the oxide solid electrolyte and uniformly dispersed it, thereby improving the ionic conductivity and increasing the charge / discharge efficiency. It is also confirmed that the battery can be driven at room temperature.

100: Electrode slurry application step
200: electrode drying process
300: Organic complex solid electrolyte slurry application process
400: UV curing process

Claims (16)

A photocrosslinking polymer mixed with a lithium salt; And
Oxide solid electrolytes;
/ RTI >
Wherein the photo-crosslinking type polymer is made of polyethylene oxide methacrylate (PEOMA), and the photo-crosslinking type polymer is mixed and distributed in the oxide solid electrolyte without containing a solvent. .
The method according to claim 1,
The lithium salt may be at least one selected from the group consisting of lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroantimonate (LiSbF ₆ ), lithium hexafluoroacetate (LiAsF ₆ ), lithium difluoromethane sulfonate _{(LiC 4 F 9 SO 3)} , lithium perchlorate (LiClO _4), lithium aluminate (LiAlO _2), lithium tetrachloro- aluminate (LiAlCl _4), lithium chloride (LiCl), lithium iodide (LiI), lithium bis oxalate reyito Wherein the electrolyte is one or more selected from the group consisting of borate (LiB (C ₂ O ₄ ) ₂ ), and lithium trifluoromethanesulfonylimide (LiTFSI).
The method according to claim 1,
Wherein the photo-crosslinkable polymer and the lithium salt are mixed in a molar ratio of [EO]: [Li] of 8 to 12: 1.
delete The method according to claim 1,
Wherein the photo-crosslinkable polymer is in a liquid state at room temperature and is cured to a solid state by photo-crosslinking when irradiated with ultraviolet light.
The method according to claim 1,
Wherein the oxide solid electrolyte is one electrolyte selected from the group consisting of LiPON, garnet, perovskite and NASICON (Na-super ionic conductor).
The method according to claim 1,
Wherein the oxide solid electrolyte has an average particle size of 10 nm to 30 占 퐉.
The method according to claim 1,
Wherein the content of the oxide solid electrolyte is 30 to 50% by weight relative to the total organic / inorganic hybrid solid electrolyte membrane.
The method according to claim 1,
Wherein the organic-inorganic composite solid electrolyte membrane is formed by crosslinking a photo-crosslinkable polymer in which the lithium salt is mixed at an interface of the oxide solid electrolyte.
The method according to claim 1,
Wherein the organic-inorganic hybrid solid electrolyte membrane has a thickness of 1 to 100 mu m.
Mixing a photocrosslinking polymer mixed with a lithium salt and an oxide solid electrolyte to prepare an electrolyte slurry;
Casting the electrolyte slurry onto an electrode layer or substrate; And
Irradiating the cast electrolyte slurry with ultraviolet light to produce a photocrosslinked organic / inorganic hybrid solid electrolyte membrane;
Lt; / RTI >
Wherein the photo-crosslinking type polymer is made of polyethylene oxide methacrylate (PEOMA), and the photo-crosslinking type polymer is mixed and distributed in the oxide solid electrolyte without containing a solvent. Gt;
12. The method of claim 11,
Wherein the content of the oxide solid electrolyte in the step of preparing the electrolyte slurry is 30 to 50% by weight based on the total organic / inorganic hybrid solid electrolyte membrane.
12. The method of claim 11,
Wherein the organic-inorganic composite solid electrolyte membrane cast on the electrode layer has a thickness of 1 to 100 mu m.
12. The method of claim 11,
Wherein the electrode layer is a positive electrode layer or a negative electrode layer.
10. A pre-solid battery comprising the organic-inorganic composite solid electrolyte membrane according to any one of claims 1 to 3 and 5 to 10.
15. A vehicle comprising the pre-solid battery of claim 15.

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