KR102654897B1 - A method for predicting ion conductivity of an electrode for all solid type battery electrolyte and selecting the same - Google Patents

Abstract

The present invention simulates the three-dimensional network structure of an electrode solid electrolyte using one or more types of inorganic particles and organic particles selected, predicts the ionic conductivity of the solid electrolyte when applied to an actual electrode, and based on the data collected in this way, This is about how to select electrodes.

Description

Method for predicting ion conductivity of an electrode for all solid type battery electrolyte and selecting the same}

The present invention relates to a method for predicting the ionic conductivity of an electrode for an all-solid-state battery and a method for manufacturing a battery by selecting an electrode with appropriate ionic conductivity.

Recently, demand for secondary batteries has been increasing in various applications as a power source for PCs, video cameras, and mobile phones, or as a power source for electric vehicles and power storage media. Among secondary batteries, lithium-based secondary batteries in particular have a higher capacity density than other secondary batteries and can operate at high voltages, so they are used in information-related devices and communication devices as secondary batteries for compactness and weight reduction, and have recently been used in electric vehicles and hybrid vehicles. The development of high-output and high-capacity lithium-based secondary batteries is in progress.

A typical lithium-based secondary battery consists of a positive electrode (cathode), a negative electrode (anode), and an electrolyte containing lithium salt interposed between them, and non-aqueous liquid electrolyte or solid electrolyte is used as the electrolyte. When a non-aqueous liquid electrolyte is used as the electrolyte, the electrolyte penetrates into the interior of the positive electrode, so an interface between the positive electrode active material constituting the positive electrode and the electrolyte is easily formed, resulting in high electrical performance.

However, since lithium-based secondary batteries use a flammable organic solvent in the liquid electrolyte, it is necessary to install a safety device to prevent ignition or rupture that may occur due to overcurrent due to a short circuit. Sometimes you lose. Additionally, in order to prevent this phenomenon, there are cases where restrictions are placed on the selection of battery materials or the design of the battery structure.

Therefore, the development of an all-solid-state battery that uses a solid electrolyte instead of a liquid electrolyte is in progress. Since all-solid-state batteries do not contain flammable organic solvents, they have the advantage of simplifying safety devices, and are recognized as batteries with excellent manufacturing costs and productivity. In addition, since it is easy to stack in series a bonding structure including a pair of electrode layers including an anode (positive electrode) layer and a cathode (negative electrode) layer and a solid electrolyte layer placed between these electrode layers, it is stable and has high capacity, It is also expected to be a technology that can produce high-output batteries.

As the solid electrolyte, a polymer material with ion conductivity or inorganic particles such as sulfide or oxide are used. To ensure ionic conductivity in the electrode, the electrode is usually manufactured by mixing an electrode active material and a solid electrolyte. When using a polymer electrolyte as an electrolyte during the manufacture of an all-solid-state battery, before manufacturing the electrode, the solid polymer electrolyte is made into a film with a predetermined thickness, the ionic conductivity is measured in the bulk state, and this is applied to the electrode. There is a problem with low predictability because the ionic conductivity and the ionic conductivity measured after being applied to the actual electrode are different.

The present invention simulates the three-dimensional network structure of an electrode solid electrolyte using one or more types of inorganic particles and organic particles selected, predicts the ionic conductivity of the solid electrolyte when applied to an actual electrode, and based on the data collected in this way, This is about how to select electrodes. Other objects and advantages of the present invention may be understood by the following description. Meanwhile, the purposes and advantages of the present invention are in the scope of the patent claims.

It can be easily seen that this can be realized by the described means or methods, and combinations thereof.

will be.

The present invention provides a method for selecting an electrode containing a solid electrolyte with improved ionic conductivity. A first aspect of the present invention relates to the method, which includes (S10) producing a composite film comprising a polymer solid electrolyte material and inorganic particles and/or organic particles; (S20) obtaining a three-dimensional network structure of a solid polymer electrolyte by selectively removing inorganic particles and/or organic particles other than the solid polymer electrolyte material from the composite film; (S30) measuring ionic conductivity of the three-dimensional network structure; And (S40) the ionic conductivity measured in (S30) is set to a preset base.

It includes a step of comparing with line).

The second aspect of the present invention, in the first aspect, is to further perform the step of measuring at least one of the following A1) to A3) before performing the step (S10):

A1) Particle size of the inorganic particles and/or organic particles introduced,

A2) The content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of the composite film, and

A3) Volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film.

In addition, the third aspect of the present invention, in the first or second aspect, further includes the step of selecting the structure of the composite film of (S1) as the model electrode structure when the measured ionic conductivity (S50) is equal to or higher than the reference value. It includes.

The fourth aspect of the present invention, according to the third aspect, further includes the step of (S60) manufacturing an electrode for an all-solid-state battery including a polymer solid electrolyte material and electrode active material particles, wherein the electrode active material particles are from B1) to B3) satisfies at least one condition:

B1) Having a particle size range within +/-10% or +/-5% of the particle size of the inorganic particles and/or organic particles contained in the model electrode structure.

B2) The content of inorganic particles and/or organic particles contained in 100% by weight of the composite film selected as the model electrode structure is +/- 10% or +/- 5% or +/- 2%. have

B3) A volume of +/- 10% or +/-5% or +/-2% of the volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film selected as the model electrode structure. Having.

In addition, the fifth aspect of the present invention is in accordance with the fourth aspect, (S70) measuring the ionic conductivity of the electrode for an all-solid-state battery and comparing the ionic conductivity with the ionic conductivity of the model electrode structure; And (S80) when the measured ionic conductivity of the all-solid-state battery electrode shows an ionic conductivity of 70% or more, 80% or more, or 90% or more compared to the ionic conductivity of the model electrode structure, the electrode manufactured in (S60) is called a model electrode. It further includes the step of selecting.

Meanwhile, in the sixth aspect of the present invention, in any one of the first to fifth aspects, (S50) when the measured ionic conductivity does not meet the standard value, at least one of the following conditions A1) to A3) is changed, The steps of repeating steps S1) to S4) are further performed:

A1) Particle size of the inorganic particles and/or organic particles introduced,

A2) Content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of composite film,

and

A3) Volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film.

Additionally, a seventh aspect of the present invention is that in any one of the first to sixth aspects, the particles include PMMA (polymethyl methacrylate).

The eighth aspect of the present invention is according to any one of the first to seventh aspects, wherein (S20) is performed by a sub-process comprising the following steps (S21) to (S23), wherein the ion conductivity is A method for selecting an electrode containing an improved solid electrolyte includes: (S21) preparing a mixed slurry by adding organic particles containing PMMA, a polymer solid electrolyte, and a dispersion medium; (S22) applying the mixed slurry to a substrate; (S23) drying the applied mixed slurry to obtain a composite film; and (S24) removing the particles from the composite film.

The electrode manufacturing method according to the present invention can obtain various electrode models and/or various solid electrolyte three-dimensional networks through a simple process by simulating an electrode by using inorganic particles or organic particles whose particle size is easy to control instead of the electrode active material. Additionally, based on this, when an electrode is actually manufactured, its ionic conductivity can be predicted. In addition, based on the electrode structure simulated in this way, the electrode can be designed by selecting the optimal shape of the active material and the electrolyte layer within the electrode. In addition, based on the electrode structure simulated in this way, the electrode can be designed by selecting the optimal shape of the active material and the electrolyte layer within the electrode.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later. Therefore, the present invention includes the matters described in such drawings. It should not be interpreted as limited to only . Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer description.
Figure 1 schematically shows the process of obtaining a three-dimensional network structure of a solid polymer electrolyte by selectively removing inorganic particles and/or organic particles according to an embodiment of the present invention.

The terms used in this specification and patent claims should not be construed as limited to their ordinary or dictionary meanings, and the inventor may appropriately define the concept of the term in order to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on principles. Therefore, the configuration shown in the examples described in this specification is only one of the most preferred embodiments of the present invention and does not represent the entire technical idea of the present invention, so various equivalents can be substituted for them at the time of filing the present application. It should be understood that there may be variations and modifications.

Throughout the specification of this application, when a part is said to be “connected” to another part, this means not only “directly connected” but also “ionically connected or electrically connected” with another element in between. Also includes cases where there are.

Throughout the specification of the present application, when it is said that a part “includes” a certain component, this means that it does not exclude other components but may further include other components, unless specifically stated to the contrary.

The terms “about,” “substantially,” and the like used throughout the specification herein are used to mean at or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and are used accurately to aid understanding of the present application. It is used to prevent unscrupulous infringers from unfairly exploiting disclosures where absolute figures are mentioned.

Throughout the specification of the present application, when a member is said to be located “on” another member, this includes not only the case where the member is in contact with the other member, but also the case where another member exists between the two members.

Throughout the specification herein, the term "combination(s) thereof" included in the surface of the Markushi format means a mixture or combination of one or more selected from the group consisting of the constituent elements described in the expression of the Markushi format, It means including one or more selected from the group consisting of the above components.

Throughout this specification, the description of “A and/or B” means “A or B or both.”

Hereinafter, embodiments of the present invention have been described in detail. However, the present invention is not limited to the specific embodiments below.

The present invention relates to a method of predicting the ionic conductivity of an electrode by creating a three-dimensional network structure and a model electrode structure composed of a polymer electrolyte, and applying the selected three-dimensional network structure and model electrode structure to an actual electrode to manufacture an electrode. will be. Additionally, the present invention relates to a method for predicting ion conductivity and a method for selecting an electrode. In the present invention, the battery is preferably an all-solid-state battery containing a solid electrolyte. Additionally, in the present invention, the solid electrolyte includes a polymer solid electrolyte. Additionally, in the present invention, the electrode includes a mixture of a solid polymer electrolyte and an electrode active material.

When manufacturing an electrode using a polymer electrolyte, it is not easy to accurately measure or predict the ionic conductivity of the electrode without actually manufacturing the electrode. The material properties of the polymer electrolyte have a great influence on the ionic conductivity of the electrode, but in addition to the material aspects, it can also be affected by the shape or length of the ionic conduction path depending on the structure of the electrolyte within the electrode. The ionic conductivity of a polymer electrolyte is measured by measuring the ionic conductivity using, for example, a film-shaped (bulk state) polymer electrolyte before applying the polymer electrolyte to the electrode, and predicting the ionic conductivity when applied to the electrode based on this, for the reasons explained above. It is difficult to accurately predict the ionic conductivity of an electrode based only on the ionic conductivity of the bulk state. Accordingly, the present invention provides a method of manufacturing a three-dimensional network structure of a polymer electrolyte and predicting the ionic conductivity of the electrode before actually applying the polymer electrolyte to the electrode to manufacture the electrode. Additionally, based on this, an electrode structure with optimal ionic conductivity can be designed to manufacture electrodes and batteries with optimized design capacity.

The method for predicting the ionic conductivity of the electrode and selecting the electrode of the present invention includes the following steps (S10) to (S40):

(S10) manufacturing a composite film containing a polymer solid electrolyte material and inorganic particles and/or organic particles;

(S20) obtaining a three-dimensional network structure of a solid polymer electrolyte by selectively removing inorganic particles and/or organic particles other than the solid polymer electrolyte material from the composite film;

(S30) measuring ionic conductivity of the three-dimensional network structure;

(S40) Compare the ionic conductivity measured in (S30) with a preset base line

A method of selecting an electrode containing a solid electrolyte with improved ionic conductivity.

First, a composite film containing a polymer solid electrolyte material and inorganic particles and/or organic particles is prepared (S10), and then the inorganic particles and/or organic particles excluding the solid polymer electrolyte material are selectively removed from the composite film (S10). S20). Through the step (S20), a three-dimensional network structure of the polymer electrolyte can be obtained.

In the present invention, the polymer electrolyte includes a polymer material that exhibits ion conductivity by adding a polymer resin to a solvated lithium salt or doping a lithium salt into a polymer resin, and is typically used as a polymer electrolyte for an all-solid-state battery. It is not particularly limited and can be appropriately selected according to the characteristics of the electrode to be manufactured.

In a specific embodiment of the present invention, the solid polymer electrolyte is a polymer resin and includes polyether-based polymer, polycarbonate-based polymer, acrylate-based polymer, polysiloxane-based polymer, phosphazene-based polymer, polyethylene derivative, alkylene oxide derivative, It may include phosphoric acid ester polymer, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymer containing an ionic dissociation group, etc. Specifically, the polymer resin is polyethylene oxide, poly(methyl methacrylate) (PMMA), polypropylene oxide (PPO), polyvinylidene fluoride (PVdF), polystyrene (PS), polyvinyl chloride (PVC), and polyvinyl oxide. Examples include alcohol (PVA), polyacrylonitrile (PAN), polyester sulfide (PES), derivatives thereof, other polymers containing ion dissociable groups, or combinations thereof. For example, the polymer solid electrolyte is a branched copolymer, a comb-shaped polymer resin, in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (pdms), and/or phosphazene is copolymerized on a PEO (polyethylene oxide) main chain as a comonomer. like polymer) and cross-linked polymer resins may be included.

According to one embodiment of the present application, the lithium salt is lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), and lithium triflate (LiTf). ), lithium hexafluoroalcenate (LiAsF ₆ ), lithium sulfide (Li ₂ S), lithium sulfate (Li ₂ SO ₄ ), lithium phosphate (Li ₃ PO ₄ ), lithium citrate (Li ₃ C ₆ H ₅ O ₇ ), Lithium bis(oxalate)borate (LiBOB), Lithium bis(nonafluorosulfonyl)methane, Lithium difluorobisoxalatophosphate (LiF ₄ OP), Lithium difluoro(oxalate)borate (LiDFOB) ), Lithium bis(pentafluoroethylsulfonyl)amide (LiBETI), Lithium bis(fluorosulfonyl) imide)(LiFSI), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), Lithium tris(trifluoro) It may include one selected from the group consisting of methanesulfonyl)methide [LiC(SO ₂ CF ₃ ) ₃ ], and combinations thereof, but is not particularly limited to these components.

Additionally, the particles, such as the inorganic particles and/or organic particles, are not particularly limited as long as they can be removed from the composite film without damaging the three-dimensional network structure of the polymer electrolyte. In the present invention, the particles are used as a substitute for the electrode active material in the composite film and are used to confirm the conditions of the electrode active material required to secure the desired level of ionic conductivity in the electrode. When using electrode active materials directly, it is not easy to secure a variety of materials that meet each experimental condition, such as particle size and particle size distribution, considering cost aspects and aspects of the active material manufacturing process. Therefore, we designed a method to simulate the electrode structure using particles that are easy to obtain and whose size and distribution can be controlled in a simple way, especially at the laboratory level. In the present invention, the particles may be inorganic particles, organic particles, or one or more of them.

In the present invention, the three-dimensional network structure can be manufactured from the following process. First, particles, polymer solid electrolyte, and dispersion medium are added to prepare a mixed slurry. In one embodiment of the present invention, the mixed slurry may further include at least one of a curing agent and an initiator to form a three-dimensional network structure of a solid electrolyte and maintain the structure. Next, the mixed slurry is applied to a substrate and dried to obtain a composite film, and then particles are removed from the composite film to obtain a three-dimensional network structure of a solid electrolyte.

In a specific embodiment of the present invention, the particles may include organic particles.

Organic particles have the advantage of being able to control the particle size by adjusting the polymerization conditions, so they can be prepared in a variety of particle size ranges depending on the experimental conditions, and thus can replace active materials of various dimensions, such as diameter.

In the present invention, the organic particles may be selected to be suitable for removal from the composite film after manufacturing the composite film without damaging the three-dimensional network structure of the polymer electrolyte. In the present invention, since the organic particles are used to replace electrode active materials, it is preferable to use particles that maintain their shape until a composite film is obtained and do not dissolve in the dispersion medium used in the mixed slurry.

In one embodiment of the present invention, removal of organic particles may be performed by dissolving the organic particles in an organic solvent. At this time, a solvent for removing organic particles is selected that is insoluble or has very low solubility in the polymer electrolyte material and can selectively remove only the used organic particles. For example, the solvent includes toluene, chloroform, and NMP, and may include one or more of these. However, the type of solvent is not limited to this, and a person skilled in the art can select and use an appropriate solvent depending on the organic particles and polymer solid electrolyte used.

According to another embodiment of the present invention, a composite film is manufactured using a UV-decomposable material such as PMMA as organic particles, and UV light is irradiated on the composite film to photodecompose the organic particles, thereby selectively removing only UV organic particles from the composite film. It can be removed. In one embodiment of the present invention, when applying the method of UV photolysis to remove organic particles, a curing agent is used together with the solid electrolyte component when manufacturing the composite film to prevent the three-dimensional network structure of the solid electrolyte from being deteriorated by UV. Additives such as ingredients or initiators can be added.

In one embodiment of the present invention, the organic particles are styrene-butadiene rubber (SBR), polybutadiene rubber, polyfluoroprene (neoprene), nitrile rubber, acrylic rubber, fluorinated rubber (FKM), PVC, polystyrene, Polystyrene, polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene (ABS), polyvinylidene fluoride, polyvinyl fluoride, PTFE, polyvinyl acetate or its copolymer, vinyl acetate-ethylene copolymer. It may contain more than one.

Meanwhile, in a specific embodiment of the present invention, the particles may be inorganic particles. Additionally, the inorganic particle may be, for example, silica. Silica particles and polymer electrolyte are added to a solvent to prepare a slurry, and then the slurry is applied to a glass substrate and dried to prepare a composite film. The composite film is then treated with a solvent such as hydrofluoric acid (aqueous solution) to dissolve the silica particles and remove them from the composite film. At this time, the polymer electrolyte must not be dissolved by the hydrofluoric acid. Silica particles can be removed by dissolving in hydrofluoric acid, and the particle size can be adjusted by methods such as mechanical milling, which has the advantage of being able to prepare a variety of particle size ranges depending on experimental conditions.

Next, the ionic conductivity of the three-dimensional network structure of the polymer electrolyte obtained through the above steps is measured (S30), and the ionic conductivity is compared with a preset base line (S40).

If the ionic conductivity condition of the preset standard value is satisfied, the structure of the composite film obtained through (S10) can be selected as the model electrode structure (S50). Additionally, the three-dimensional network structure is applied to the electrode. In the present invention, “satisfies a preset standard value” means that the ionic conductivity of the three-dimensional network structure is greater than or equal to the set standard value.

In one embodiment of the present invention, the reference value may be 1x10 ^-7 S/cm or more, 1x10 ^-6 S/cm or more, 1x10 ^-5 S/cm or more, and 1x10 ^-4 S/cm or more. Alternatively, in one embodiment of the present invention, the reference value may be set at a level of 20% or more compared to the ionic conductivity of a solid polymer electrolyte layer of the same thickness. For example, an electrolyte layer having the same thickness as the electrode model is manufactured using the same ion conductive polymer material, its ionic conductivity is measured, and the ionic conductivity of the electrode model is compared to the ionic conductivity of the solid polymer electrolyte layer by 20%. If the ionic conductivity is above or equal to the above, the electrode model is assumed to satisfy the preset standard value. In other words, it means that the percentage of the ionic conductivity of the electrode model to the ionic conductivity of the solid electrolyte layer is 20% or more, and can be expressed as the equation below.

ceremony)

(ion conductivity of electrode model/ion conductivity of solid electrolyte layer)

In this specification, the 'solid polymer electrolyte layer of the same thickness' refers to a solid polymer that does not contain particles and has a porosity of 10% or less, preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. This means that it is a dense membrane made only of electrolyte and has the same thickness as the electrode model with a three-dimensional network structure. In other words, it looks like the pores formed by removing particles from an electrode model with a three-dimensional network structure are filled with a solid polymer electrolyte. In the present invention, it is preferable that the polymer solid electrolyte used in the 'solid polymer electrolyte layer of the same thickness' and the 'electrode model with a three-dimensional network structure', which are the objects of comparison, are the same.

Meanwhile, the porosity can be measured using BEL JAPAN's BELSORP (BET equipment) using an adsorbed gas such as nitrogen, or can be measured by a method such as mercury intrusion porosimetry. Or, in one embodiment of the present invention, the true density is calculated from the density (apparent density) of the obtained electrode model, the composition ratio of the materials included in the electrode model, and the density of each component, and the apparent density and true density ( Porosity can be calculated from the difference in net density.

The ionic conductivity of an electrode can depend on various conditions such as the distribution and structure of the electrolyte, the resulting ion conduction path, and the length or width of the path. The present inventors predicted that the three-dimensional structure of the polymer electrolyte in the electrode would be influenced by the physical properties of electrode compound components such as active materials included in the electrode in addition to the polymer electrolyte. These physical properties may include various conditions such as the particle size of the active material, distribution of the particle size, and distribution state of the active material.

Therefore, in the present invention, “applying the three-dimensional network structure to the electrode” means applying at least one of the various conditions applied to manufacture the network structure to the electrode manufacturing. The conditions may be listed as a) to h).

a) Polyelectrolyte used to fabricate the three-dimensional network structure

b) Content of polyelectrolyte used to prepare the three-dimensional network structure

c) Particle size (D50, D90, etc.) of the particles used to manufacture the three-dimensional network structure.

d) Particle size distribution of particles used to fabricate the three-dimensional network structure.

e) Content of particles used to fabricate the three-dimensional network structure

f) the nature of the solvent used to prepare the three-dimensional network structure (solubility, polarity, viscosity, etc.)

g) nature of the solvent used to prepare the three-dimensional network structure

h) Solids content and/or slurry concentration

The above conditions may be completely the same or, in some cases, may satisfy a predetermined range. For example, in the case of active material particles, the particle size may be within +/-10% of the particle size of the inorganic particles and/or organic particles included in the model electrode structure. Alternatively, it may have a content of +/-10% of the content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of the composite film selected as the model electrode structure. Alternatively, it may have a volume of +/-10% of the volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film selected as the model electrode structure.

Additionally, in a specific embodiment of the present invention, a step of manufacturing an electrode for an all-solid-state battery may be further performed with reference to the selected three-dimensional network structure and its manufacturing conditions (S60). At this time, since the electrode active material is added instead of the inorganic and/or organic particles in the composite film, it is preferable that the electrode active material particles satisfy at least one of the following conditions B1) to B3):

B1) Having a particle size range within +/-10% or +/- 5% of the particle size of the inorganic particles and/or organic particles contained in the model electrode structure.

B2) The content of inorganic particles and/or organic particles contained in 100% by weight of the composite film selected as the model electrode structure is +/- 10% or +/- 5% or +/- 2%. have

B3) A volume of +/- 10% or +/- 5% or +/- 2% of the volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film selected as the model electrode structure. Having.

Meanwhile, when the electrode is manufactured through the above-described steps, a step of measuring the ionic conductivity of the electrode and comparing it with the ionic conductivity of the model electrode structure or three-dimensional network structure can be further performed (S70). If the ionic conductivity of the electrode is greater than 70%, or greater than 80%, or greater than 90% of the ionic conductivity of the model electrode structure or the ionic conductivity of the three-dimensional network structure, or has a higher ionic conductivity compared to these ionic conductivities. If indicated, the electrode can be selected as a model electrode (S80).

Meanwhile, if the ionic conductivity measured in the three-dimensional network structure does not reach the preset standard, the manufacturing conditions can be changed and the changed conditions can be reapplied to the manufacturing of the three-dimensional network structure. For example, at least one of the conditions A1) to A3) below can be changed. In addition, the above-described processes S10) to S40) can be repeatedly performed according to changed conditions and a three-dimensional network structure can be obtained.

A1) Particle size of the inorganic particles and/or organic particles introduced,

A2) Content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of composite film,

and

A3) Volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film.

In one embodiment of the present invention, the electrode can be manufactured by attaching the electrode active material to the electrode current collector according to a common method known in the art. Non-limiting examples of the positive electrode active material among the electrode active materials include common positive electrode active materials that can be used in the positive electrode of conventional electrochemical devices, especially lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, or these. formed by combination

Lithium intercalation materials such as complex oxides are preferred. Non-limiting examples of the negative electrode active material include common negative electrode active materials that can be used in the negative electrode of conventional electrochemical devices, especially lithium metal or lithium alloy, carbon, petroleum coke, activated carbon, Graphite

Lithium adsorption materials such as graphite or other carbons are preferred. Non-limiting examples of the positive current collector include foil made of aluminum, nickel, or a combination thereof, and non-limiting examples of the negative current collector include foil made of copper, gold, nickel, or a copper alloy, or a combination thereof. There are foils etc. that are manufactured.

Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. Examples of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

(1) Production of film

Example 1 -One

A polymer solution with a concentration of 4 wt% was prepared by dissolving PEO (Mw = 4,000,000 g/mol) in acetonitrile (AN) solvent. Additionally, LiFSI as a lithium salt was added to the polymer solution so that [EO]/[Li+]=20/1 and mixed. The polymer solution was stirred overnight at 70°C for about 24 hours to sufficiently dissolve PEO (polyethylene oxide) and lithium salt. Poly methyl methacrylate (PMMA) particles (D50 5㎛) were added to the solution and stirred overnight at room temperature for about 24 hours. The amount of PMMA was set to 50% by weight of the solid content (PEO + lithium salt + initiator + hardener). Before coating, an initiator and curing agent solution was prepared in advance, stirred for about 1 hour, and then added to the polymer solution. At this time, PEGDA (Polyethylene glycol diacrylate, Mw = 575) was used as the curing agent, and BPO (Benzoyl peroxide) was used as the initiator. PEGDA was added in an amount of 20 parts by weight compared to 100 parts by weight of PEO, and BPO was added in an amount of 1 part by weight compared to 100 parts by weight of PEGDA. After adding the initiator and curing agent solution, coating was performed. Coating was done using a doctor blade and on a release film. The coating gap was controlled to 800㎛, and the coating speed was controlled to 20mm/min. The coated solution was moved to a glass plate with a release film, maintained well, left in the chamber at room temperature overnight, and then dried under vacuum at 100°C for 12 hours. Afterwards, a composite film with a thickness of 50㎛ was obtained through rolling. The composite film was irradiated with UV light to decompose and remove PMMA particles from the composite film, thereby obtaining a porous film composed of a three-dimensional network structure of a polymer solid electrolyte. The pore volume of the porous film was 50 vol%.

The prepared film was cut into a circular shape with a diameter of 1.7671 cm ² and sandwiched between metal plates (SUS material) of the same size to produce a coin-type battery. After measuring impedance at room temperature, ionic conductivity was calculated. For ionic conductivity, alternating current impedance is measured from 500 kHz to 0.1 Hz, and resistance R is calculated from that measurement. Additionally, ionic conductivity = 1/R x 1d/A was obtained from this resistance R and the area A and thickness d of the measurement sample.

Example 1-2

A film was prepared in the same manner as Preparation Example 1, except that the D50 of the PMMA particles used was 10㎛, and the ionic conductivity was measured. The pore volume of the porous film was 50 vol%.

Example 1-3

A porous film was prepared in the same manner as Preparation Example 1, except that the D50 of the PMMA particles used was 10㎛ and the PMMA content in the solid content was 60wt%, and the ionic conductivity was measured. The pore volume of the obtained porous film was 40 vol%.

Example 1-4

A composite film was prepared in the same manner as Preparation Example 1, except that silica particles (D50 5㎛~10㎛) were used instead of PMMA, and ionic conductivity was measured. The obtained composite film was placed in a 3 wt% HF aqueous solution and left to stand for 30 minutes to remove silica particles and prepare a porous film. The pore volume of the obtained porous film was 50 vol%.

Examples 1-5

A composite film was prepared in the same manner as Preparation Example 1, except that the PMMA particles used were 10㎛ and the PMMA content was 70wt%, and the ionic conductivity was measured. The pore volume of the obtained porous film was 30 vol%.

Reference example

A polymer solution with a concentration of 4 wt% was prepared by dissolving PEO (Mw = 4,000,000 g/m ol) in acetonitrile (AN) solvent. At this time, LiFSI was added as a lithium salt so that [EO]/[Li+]=20/1. The prepared polymer solution was stirred overnight at 70°C for about 24 hours to ensure that PEO and lithium salt were sufficiently dissolved. Before coating, an initiator and curing agent solution was prepared in advance, stirred for about 1 hour, and then added to the polymer solution. At this time, PEGDA (Mw = 575) was used as the curing agent, and BPO was used as the initiator. PEGDA was added in an amount of 20 parts by weight compared to 100 parts by weight of PEO, and BPO was added in an amount of 1 part by weight compared to 100 parts by weight of PEGDA. After adding the initiator and curing agent solutions, the solutions were sufficiently mixed and then coating was performed. Coating was done using a doctor blade and was applied on a release film. The coating gap is 800㎛, and the coating speed is 20mm/min. The coated solution was moved to a glass plate with the release film, kept well leveled, maintained in the chamber at room temperature overnight, and then vacuum dried at 100°C for about 12 hours. Afterwards, a film with a thickness of 50㎛ was obtained through rolling, and the ionic conductivity was measured.

Example 1-1
Example 1-2
Example 1-3
Example 1-4
Examples 1-5
Reference example
Ion conductivity (S/cm, room temperature)
2.5x10 ^-7
2.2x10 ^-7
1.6x10 ^-7
1.3x10 ^-7
0.9x10 ^-7
5x10 ^-7

As in the experimental example, the PEO-only solid electrolyte membrane of the reference example showed the highest ionic conductivity value. This is the standard for calculating the reference value as the tortuosity of a simple film type in bulk is 1. When an electrode active material is included, organic particles (e.g., spherical PMMA) or inorganic particles (e.g., silica particles) are used instead of the active material to check the ionic conductivity according to the electrode structure, which is determined by the particle size and content of the active material. was used to predict the ionic conductivity of the electrode actually obtained. When the same solid electrolyte material is applied to the electrode, the ionic conductivity within the electrode decreases due to tortuosity caused by the active material compared to a simple film-type solid electrolyte membrane in the bulk state. As the active material content increases, the content of solid electrolyte in the electrode decreases, resulting in a decrease in ionic conductivity. As the solid electrolyte content decreases to 30wt% (Example 1-5), the ionic conductivity becomes very low to 18% compared to the bulk ionic conductivity, which may affect performance. In this way, it was confirmed that the ionic conductivity in the electrode is preferably 20% or more compared to the bulk state.

Example 2: Preparation of electrodes

A polymer solution with a concentration of 4 wt% was prepared by dissolving PEO (Mw = 4,000,000 g/mol) in acetonitrile (AN) solvent. Additionally, LiFSI as a lithium salt was added to the polymer solution so that [EO]/[Li+]=20/1 and mixed. The polymer solution was stirred overnight at 70°C for about 24 hours to ensure that PEO and lithium salt were sufficiently dissolved. The electrode active material (LiNi ₈ Mn ₁ Co ₁ O ₂ ) (D505㎛) was added to the solution in an amount equal to the amount of solid content (PEO + lithium salt + initiator + curing agent), and then stirred overnight at room temperature for about 24 hours. Before coating, an initiator and curing agent solution was prepared in advance, stirred for about 1 hour, and then added to the polymer solution. At this time, PEGDA (Mw = 575) was used as the curing agent, and BPO was used as the initiator. PEGDA was added in an amount of 20 parts by weight compared to 100 parts by weight of PEO, and BPO was added in an amount of 1 part by weight compared to 100 parts by weight of PEGDA. After adding the initiator and curing agent solutions, coating was performed when the solutions were sufficiently mixed. Coating was done using a doctor blade and on a release film. The coating gap was controlled to 200㎛, and the coating speed was controlled to 20mm/min. The coated solution was moved to a glass plate as a release film, maintained well, left in a chamber at room temperature overnight, and then dried under vacuum at 100°C for 12 hours. Afterwards, the thickness was adjusted to 50㎛ through rolling. Finally, an electrode with a solid electrolyte content of 50 vol% was obtained.

(2) Measurement of ionic conductivity

The prepared electrode was cut into circular shapes with a diameter of 1.4875 cm ² to prepare two sheets, and a coin-type battery was manufactured by interposing the solid electrolyte membrane prepared in Preparation Example 5 between them. After measuring impedance at room temperature, ionic conductivity was calculated. Its ionic conductivity value was 2.4x10 ^-7 , which was confirmed to be in a similar range to that of Preparation Example 1.

In this way, the present invention can be applied to design the structure of the electrode, such as selection of electrode material showing the desired ionic conductivity range, electrode thickness, and solid electrolyte content. The electrode model manufactured according to the present invention has the advantage of being able to derive reliable prediction results as it has been confirmed to exhibit values similar to the ionic conductivity values of the actual electrode. As such, the present invention has been described in detail through various embodiments. However, the above embodiments are for illustrating the present invention, and the scope of the present invention is not limited to these only.

10 Organic and/or inorganic particles

20 3D network structure

Claims (8)

(S10) manufacturing a composite film containing a polymer solid electrolyte material and inorganic particles and/or organic particles;
(S20) obtaining a three-dimensional network structure of a solid polymer electrolyte by selectively removing inorganic particles and/or organic particles other than the solid polymer electrolyte material from the composite film;
(S30) measuring ionic conductivity of the three-dimensional network structure; and
(S40) Comparing the ionic conductivity measured in (S30) with a preset base line. A method of selecting an electrode containing a solid electrolyte comprising a.
According to paragraph 1,
A method of selecting an electrode containing a solid electrolyte further comprising the step of measuring at least one of the following A1) to A3) before performing the step (S10):
A1) Particle size of the inorganic particles and/or organic particles introduced,
A2) Content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of composite film,
and
A3) Volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film.
According to paragraph 1,
(S50) A method of selecting an electrode containing a solid electrolyte further comprising the step of selecting the structure of the composite film of (S10) as a model electrode structure when the measured ionic conductivity is greater than the above reference value.
According to paragraph 3,
(S60) further comprising manufacturing an electrode for an all-solid-state battery containing a polymer solid electrolyte material and electrode active material particles, wherein the electrode active material particles are a solid electrolyte-containing electrode that satisfies at least one of the conditions B1) to B3) below. How to select:
B1) Having a particle size range within +/-10% or +/-5% of the particle size of the inorganic particles and/or organic particles contained in the model electrode structure.
B2) The content of inorganic particles and/or organic particles contained in 100% by weight of the composite film selected as the model electrode structure is +/- 10% or +/- 5% or +/- 2%. have
B3) A volume of +/- 10% or +/- 5% or +/- 2% of the volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film selected as the model electrode structure. go
load.
According to paragraph 4,
(S70) measuring the ionic conductivity of the electrode for an all-solid-state battery and comparing the ionic conductivity with the ionic conductivity of a model electrode structure; and
(S80) If the measured ionic conductivity of the all-solid-state battery electrode shows an ionic conductivity of 70% or more compared to the ionic conductivity of the model electrode structure, selecting the electrode manufactured in (S60) as the model electrode: A solid electrolyte further comprising: How to select inclusion electrodes.
According to paragraph 1,
(S50) If the measured ionic conductivity does not meet the above standard value, a method of selecting an electrode containing a solid electrolyte further includes changing at least one of the conditions A1) to A3) below and repeating steps S10) to S40). :
A1) Particle size of the inorganic particles and/or organic particles introduced,
A2) Content ratio (%) of inorganic particles and/or organic particles contained in 100% by weight of composite film,
and
A3) Volume ratio (%) of inorganic particles and/or organic particles contained in 100 vol% of the composite film.
According to paragraph 1,
A method for selecting an electrode containing a solid electrolyte in which the particles contain PMMA.
According to paragraph 1,
The (S20) method for selecting an electrode containing a solid electrolyte is performed by a sub-process including the following steps (S21) to (S24):
(S21) preparing a mixed slurry by adding organic particles, a polymer solid electrolyte, and a dispersion medium;
(S22) applying the mixed slurry to a substrate;
(S23) drying the applied mixed slurry to obtain a composite film; and
(S24) removing the particles from the composite film.

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