KR102310319B1 - Organic-Inorganic composite solid polymer electrolyte, integrated electrode structure and electrochemical device including the same, and manufacturing method of the organic-inorganic composite solid polymer electrolyte - Google Patents

Abstract

Disclosed are an organic-inorganic composite solid polymer electrolyte, an integrated electrode structure and an electrochemical device including the same, and a method of manufacturing the organic-inorganic composite solid polymer electrolyte. The organic-inorganic composite solid polymer electrolyte may include an inorganic lithium ion conductor; a copolymer of a crosslinkable precursor comprising a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer; and lithium salt; by including, ion conductivity, mechanical properties and electrochemical stability are improved, and in particular ^{, it has room temperature ionic conductivity of 10 −4} S/cm or more, so that it can be used in various electrochemical devices.

Description

Organic-inorganic composite solid polymer electrolyte, integrated electrode structure and electrochemical device including same, and method for manufacturing the organic-inorganic composite solid polymer electrolyte, integrated electrode structure and electrochemical device including the same, and manufacturing method of the organic-inorganic composite solid polymer electrolyte}

An organic-inorganic composite solid polymer electrolyte, an integrated electrode structure and an electrochemical device including the same, and a method of manufacturing the organic-inorganic composite solid polymer electrolyte.

According to the trend of light, thin, compact and portable electric and electronic products, a secondary battery, which is a core component, is also required to be lightweight and miniaturized, and the development of a battery having high output and high energy density is required. In response to this demand, one of the high-performance, next-generation, high-tech new batteries that are receiving the most attention recently is a lithium metal secondary battery.

However, the lithium metal electrode used as an electrode has high reactivity with the electrolyte component, and forms a passivation film by reaction with the organic electrolyte, and oxidation (dissolution) and reduction (precipitation) of lithium on the lithium metal surface during charging and discharging. , deposition) reaction is non-uniformly repeated, so the formation and growth of the passivation film is extreme. Accordingly, not only causes a decrease in the capacity of the battery during charging and discharging, but also, as the charging and discharging process is repeated, dendrites in which lithium ions grow in the form of needles are formed on the surface of the lithium metal, thereby prolonging the charge/discharge cycle of the lithium secondary battery. It is shortened and causes safety problems of the battery, such as causing a short between electrodes.

In order to solve this problem, Korean Patent Application Laid-Open No. 10-2016-0079405 proposes a technique for manufacturing a solid polymer electrolyte membrane having properties that improve ionic conductivity, mechanical properties, process easiness, and electrochemical stability compared to conventional solid electrolytes. Due to the nature of the chain polymer such as polyethyleneoxide methacrylate (PEOMA), when the content of the inorganic additive is 40 to 50% by weight, it is difficult to actually see the effect.

In the case of Korean Patent Registration No. 10-1793168, when manufacturing a composite solid electrolyte, the polymer is polyethylene oxide, polyethylene glycol, polypropylene oxide, polysiloxane, polyphosphazene, etc. Using a material with very low ionic conductivity at room temperature is very difficult to use at room temperature, and it is expected that the battery can be used at 50°C or higher.

Typically, PEO is a well-known ion conductive polymer, but its ionic conductivity at room temperature is 10 ^-7 S/cm, so it cannot be applied to a battery operated at room temperature. possible polymer electrolytes. When these polymers ^{are combined with an inorganic ceramic material at a level of 10 -4} S/cm, the room temperature ionic conductivity is also thought to be lower.

In order to solve this problem, we are developing an organic/inorganic composite electrolyte that can improve room temperature ionic conductivity and secure mechanical strength while minimizing or reducing the ionic conductivity of inorganic ceramic materials with excellent ionic conductivity, such as LLZO, LPS, and LGPS. R&D is required.

One aspect of the present invention is to provide an organic-inorganic composite solid polymer electrolyte capable of securing improvement in ionic conductivity and mechanical strength at room temperature without lowering or minimizing the ionic conductivity of the inorganic lithium ion conductor on the surface of a lithium metal electrode.

Another aspect of the present invention is to provide an integrated electrode structure to which the organic-inorganic composite solid polymer electrolyte is applied.

Another aspect of the present invention is to provide an electrochemical device to which the organic-inorganic composite solid polymer electrolyte is applied.

Another aspect of the present invention is to provide a method for preparing the organic-inorganic composite solid polymer electrolyte.

In one aspect of the present invention,

inorganic lithium ion conductor;

a copolymer of a crosslinkable precursor comprising a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer; and

lithium salt;

There is provided an organic-inorganic composite solid polymer electrolyte comprising a.

In another aspect of the invention,

lithium metal electrode; and disposed on the lithium metal electrode and the solid polymer electrolyte is provided.

In another aspect of the invention,

An electrochemical device including the electrode structure is provided.

In another aspect of the invention,

Preparing an inorganic lithium ion conductor, a crosslinkable precursor including a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer, and a precursor mixture including a lithium salt; and

applying and curing the precursor mixture in the form of a film;

There is provided a method for producing the organic-inorganic composite solid polymer electrolyte comprising a.

The organic-inorganic composite solid polymer electrolyte according to an embodiment has high elasticity and high strength characteristics, and can exhibit high ionic conductivity and mechanical strength at room temperature without deterioration of the ionic conductivity characteristics of the inorganic lithium ion conductor used, and pressure during electrolyte membrane manufacturing It can be manufactured over a large area without The organic-inorganic composite solid polymer electrolyte may be applied to various electrochemical devices including lithium metal secondary batteries to improve performance.

1 is a graph showing the results of measuring the ionic conductivity at room temperature of organic-inorganic composite solid polymer electrolyte membranes prepared in Examples 1 to 3 and Comparative Example 1. FIG.
2 is a graph showing the results of measuring the ionic conductivity according to the temperature change of the organic-inorganic composite solid polymer electrolyte membranes prepared in Examples 1 to 3 and Comparative Example 1. Referring to FIG.

The present inventive concept described below can apply various transformations and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present inventive concept to a specific embodiment, and it should be understood to include all transformations, equivalents or substitutes included in the technical scope of the present inventive idea.

Terms used below are only used to describe specific embodiments, and are not intended to limit the present inventive concept. The singular expression includes the plural expression unless the context clearly dictates otherwise. Hereinafter, terms such as “comprises” or “have” are intended to indicate that a feature, number, step, action, component, part, component, material, or combination thereof described in the specification is present, but one or the It should be understood that the above does not preclude the possibility of the presence or addition of other features, numbers, steps, operations, components, parts, components, materials, or combinations thereof. "/" used below may be interpreted as "and" or "or" depending on the situation.

In the drawings, in order to clearly express various components, layers, and regions, diameters, lengths, and thicknesses are enlarged or reduced. Throughout the specification, like reference numerals are assigned to similar parts. Throughout the specification, when a part, such as a layer, film, region, plate, etc., is referred to as “on” or “on” another part, this includes not only the case where it is directly on the other part, but also the case where there is another part in the middle. . Throughout the specification, terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. Some of the components may be omitted from the drawings, but this is for helping understanding of the features of the invention and is not intended to exclude the omitted components.

Unless otherwise specified herein, "substitution" means that at least one hydrogen atom is a halogen atom (F, Cl, Br, I), a C1 to C20 alkoxy group, a nitro group, a cyano group, an amino group, an imino group, an azido group, amidino group, hydrazino group, hydrazono group, carbonyl group, carbamyl group, thiol group, ester group, carboxyl group or a salt thereof, sulfonic acid group or a salt thereof, phosphoric acid or a salt thereof, C1 to C20 alkyl group, C2 to C20 alkenyl group, C2 to C20 alkynyl group, C6 to C20 aryl group, C3 to C20 cycloalkyl group, C3 to C20 cycloalkenyl group, C3 to C20 cycloalkynyl group, C2 to C20 heterocycloalkyl group, C2 to C20 heterocycloalkenyl group , C2 to C20 heterocycloalkynyl group, C3 to C20 heteroaryl group, or a combination thereof means substituted with a substituent.

In addition, unless otherwise specified in the present specification, "hetero" means that at least one hetero atom among N, O, S and P is included in the formula.

In addition, unless otherwise specified herein, "(meth)acrylate" means that both "acrylate" and "methacrylate" are possible, and "(meth)acrylic acid" is "acrylic acid" and "methacrylic acid" “It means that both are possible.

Hereinafter, an exemplary organic-inorganic composite solid polymer electrolyte, an electrode structure and an electrochemical device including the same, and a method of manufacturing the organic-inorganic composite solid polymer electrolyte will be described in detail with reference to the accompanying drawings.

Organic-inorganic composite solid polymer electrolyte according to an embodiment,

inorganic lithium ion conductor;

a copolymer of a crosslinkable precursor comprising a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer; and

lithium salt;

The organic-inorganic composite solid polymer electrolyte uses a cross-linked copolymer prepared with a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer as the main skeleton as a polymer matrix, and inorganic lithium ion conductors are embedded therein in the form of particles. can have a form. In the organic-inorganic composite solid polymer electrolyte, the copolymer itself has excellent mechanical properties, and even when a large amount of inorganic lithium ion conductor is mixed, the shape of the membrane can be maintained without dropping the inorganic lithium ion conductor, and excellent ionic conductivity can be secured. can

In the organic-inorganic composite solid polymer electrolyte, the inorganic lithium ion conductor may include at least one selected from oxide-based, phosphate-based, sulfide-based, and LiPON-based inorganic materials having lithium ion conductivity.

The inorganic lithium ion conductor may be, for example, a garnet-type compound, an argyrodite-type compound, a lithium super-ion-conductor (LISICON) compound, a Na super ionic conductor-like (NASICON) compound, or lithium nitride (Li nitride), lithium hydride, perovskite, lithium halide, and at least one selected from the group consisting of sulfide-based compounds.

The inorganic lithium ion conductor is, for example, Garnet-based ceramics Li _3+x La ₃ M ₂ O ₁₂ (0≤x≤5, M = W, Ta, Te, Nb and Zr), doping, Garnet-based ceramics Li _7-3x M' _x La ₃ M ₂ O ₁₂ (0<x≤1, at least one of MW, Ta, Te, Nb, and Zr, and M' = Al, Ga, Nb , Ta, Fe, Zn, Y, Sm and Gd), Li _1+x+y Al _x Ti _2-x Si _y P _3-y O ₁₂ (0<x<2, 0≤y<3) , BaTiO ₃ , Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT)(O≤x<1, O≤y<1),Pb(Mg _1/3 Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ ,0<x<2,0<y<3), lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0<x<2, 0<y<1, 0<z<3), Li _1+x+y (Al, Ga) _x (Ti, Ge) _2-x Si _y P _3-y O ₁₂ (O≤x≤1, O≤y≤1), lithium lanthanide titanate (Li _x La _y TiO ₃ , 0<x<2) , 0<y<3), lithium germanium thiophosphate (LixGeyPzSw, 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li _x N _y , 0 <x<4, 0<y<2), SiS ₂ (Li _x Si _y S _z , 0≤<3,0<y<2, 0<z<4) series glass, P ₂ S ₅ (Li _x P _y S _z , 0≤x<3, 0<y<3, 0<z<7) series glass, Li _3x La _2/3-x TiO ₃ (0≤x≤1/6), Li ₇ La ₃ Zr ₂ O ₁₂ , Li _1+y Al _y Ti _2-y (PO ₄ ) ₃ (0≤y≤1) and Li _1+z Al _z Ge _2-z (PO ₄ ) ₃ (0≤z≤1), Li ₂ O, LiF, LiOH, Li ₂ CO ₃ , LiAlO ₂ , Li ₂ O-Al ₂ O ₃ -SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ Ceramics, Li ₁₀ GeP ₂ S ₁₂ , Li _3.25 Ge _0.25 P _0.75 S ₄ , Li ₃ PS ₄ , Li ₆ PS ₅ Br, Li ₆ PS ₅ Cl, Li ₇ PS ₅ , Li ₆ PS ₅ I, Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ , LiTi ₂ (PO ₄ ) ₃ , LiGe ₂ ( PO ₄ ) ₃ , LiHf ₂ (PO ₄ ) ₃ , LiZr ₂ (PO ₄ ) ₃ , Li ₂ NH ₂ , Li ₃ (NH ₂ ) ₂ I, LiBH ₄ , LiAlH ₄ , LiNH ₂ , Li _0.34 La _0.51 TiO _2.94 , LiSr ₂ Ti ₂ NbO ₉ , Li _0.06 La _0.66 Ti _0.93 Al _0.03 O ₃ , Li _0.34 Nd _0.55 TiO ₃ , Li ₂ CdCl ₄ , Li ₂ MgCl ₄ , Li ₂ ZnI ₄ , Li ₂ CdI ₄ , Li _4.9 Ga _{0.5 +δ} La ₃ Zr _1.7 W _0.3 O ₁₂ (0≤δ<1.6), Li _4.9 Ga _0.5+δ La ₃ Zr _1.7 W _0.3 O ₁₂ (1.7≤δ≤2.5), Li _5.39 Ga _0.5+δ La ₃ Zr _1.7 W _0.3 O ₁₂ (0≤δ≤1.11), Lithium Phosphorus Sulfide (LPS), Li ₃ PS ₄ ), Lithium Tin Sulfide (LTS), Li ₄ SnS ₄ ), Lithium Phosphorus Sulfur chloride iodide (Lithium Phosphorus Sulfur Chloride Iodide (LPSCLL), Li ₆ PS ₅ Cl _0.9 I _0.1 ), lithium tin phosphorus sulfide (Lithium Tin Phosphorus Sulfide (LSPS), Li ₁₀ SnP ₂ S ₁₂ ), Li ₂ S, Li ₂ SP ₂ S ₅ , Li ₂ S-SiS ₂ , Li ₂ S-GeS ₂ , Li ₂ SB ₂ S ₅ , and Li ₂ S-Al ₂ S ₅ at least one selected from the group consisting of can do.

For example, as the inorganic lithium ion conductor, garnet-type LLZO, Al doped Lithium Lanthanum Zirconium Oxide (Li _7-3x Al _x La ₃ Zr ₂ O ₁₂ ) (0<x≤1), a pseudo oxide-type solid electrolyte Lithium Lanthanum Titanate (LLTO) (Li _0.34 La _0.51 TiOy) (0<y≤3), Lithium Aluminum Titanium Phosphate (LATP) (Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ ), etc. may be used as the sulfur compound. are Lithium Phosphorus Sulfide (LPS) (Li ₃ PS ₄ ), Lithium Tin Sulfide (LTS) (Li ₄ SnS ₄ ) and Lithium Phosphorus Sulfur Chloride Iodide (LPSCLL) (Li ₆ PS ₅ Cl _0.9 I _0.1 ), Lithium Tin Phosphorus Sulfide (LSPS) (Li ₁₀ SnP ₂ S ₁₂ ) and the like can be used.

According to an embodiment, the inorganic lithium ion conductor may include garnet-type ceramics represented by Formula 3 below or aluminum-doped ceramics represented by Formula 4 below.

[Formula 3]

Li _x La _y Zr _z O ₁₂

In the above formula, 6<x<9, 2<y<4, and 1<z<3.

[Formula 4]

Li _x La _y Zr _z Al _w O ₁₂

In the above formula, 5<x<9, 2<y<4, 1<z<3, and 0<w<l.

The inorganic lithium ion conductor may have a particle or a columnar structure.

In the organic-inorganic composite solid polymer electrolyte, grains of the inorganic lithium ion conductor may have a polyhedral shape. In the case of having a polyhedral shape as described above, the contact area between the grains increases, so that the ion conduction resistance can be reduced, and the electrochemical reaction kinetics can be increased due to the high possibility of contact between the crystal plane and the active material, which is advantageous for the charge transfer reaction. .

The inorganic lithium ion conductor may have an average particle size in the range of 10 nm to 30 μm. For example, the average particle size of the inorganic lithium ion conductor may be in the range of 100 nm to 20 μm, 200 nm to 10 μm, 300 nm to 1 μm, or 400 nm to 600 nm. When the average particle size is within the above range, it is possible to reduce the film thickness of the solid polymer electrolyte while being easily dispersed in the precursor solution.

The content of the inorganic lithium ion conductor may be 30 to 90% by weight, 40 to 85% by weight, or 50 to 80% by weight based on the total weight of the inorganic lithium ion conductor and the copolymer. In the above range, an organic-inorganic composite solid polymer electrolyte having high lithium ion conductivity can be provided, and composite with a copolymer is possible. The organic-inorganic composite solid polymer electrolyte may exhibit high ionic conductivity even when the content of the inorganic lithium ion conductor exceeds 50% by weight based on the total weight of the inorganic lithium ion conductor and the copolymer.

In the organic-inorganic composite solid polymer electrolyte, the copolymer of the crosslinkable precursor including the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer controls the crystallinity of the polymer to maintain an amorphous state, ionic conductivity and electricity Chemical properties can be improved. The cross-linked matrix prepared with the urethane group-containing polyfunctional acrylic monomer and polyfunctional block copolymer as the main skeleton has very low crystallization of the polymer itself, and the movement of lithium ions due to the segmental motion of the polymer in the inner amorphous region is free. Conductivity can be improved. In addition, the copolymer has a polymer cross-linked structure to improve the mechanical properties of the copolymer itself, and to prevent the inorganic lithium ion from being uniformly dispersed in the polymer matrix and not falling off from the polymer.

As a crosslinking precursor, the urethane group-containing polyfunctional acrylic monomer may include diurethane dimethacrylate, diurethane diacrylate, or a combination thereof.

According to an embodiment, the urethane group-containing polyfunctional acrylic monomer may include diurethane dimethacrylate represented by Chemical Formula 1 below.

[Formula 1]

In the above formula, each R is independently a hydrogen atom or a C1-C3 alkyl group.

Since the urethane group-containing polyfunctional acrylic monomer has high mechanical strength and elasticity including the urethane moiety, when forming a copolymer structure with the polyfunctional block copolymer, it maintains high mechanical strength and has elasticity. A composite solid polymer electrolyte can be prepared.

In addition to the urethane group-containing polyfunctional acrylic monomer, other monomers containing a polyfunctional functional group having a similar structure may be mixed and used. As other monomers including such a polyfunctional functional group, for example, from the group consisting of urethane acrylate methacrylate, urethane epoxy methacrylate, Arkema's product names Satomer N3DE180, N3DF230, etc. One or more selected may be used.

As a crosslinkable precursor, the multifunctional block copolymer may include a diblock copolymer or a triblock copolymer including (meth)acrylate groups at both ends, and a polyethylene oxide repeating unit and a polypropylene oxide repeating unit. .

According to one embodiment, the polyfunctional block copolymer includes a (meth)acrylate group at both ends, and a triblock copolymer consisting of a polyethylene oxide first block, polypropylene oxide second block, and polyethylene oxide third block. may include.

According to one embodiment, the polyfunctional block copolymer may be represented by the following formula (2).

[Formula 2]

In the above formula, x, y, and z are each independently an integer of 1 to 50.

The polyfunctional block copolymer having the above structure is similar in structure to the well-known polyethylene glycol dimethacrylate (PEGDMA), but in the case of PEGDMA, it has a single linear structure and has a high degree of crystallinity and cracks according to the degree of crosslinking after crosslinking polymerization. This may occur, but the polyfunctional block copolymer is a block copolymer of propylene oxide and ethylene oxide and breaks the crystallinity shown in the ethylene oxide single structure, and due to two different polymer blocks, it is an organic-inorganic composite solid polymer electrolyte. Flexibility can be added.

The weight average molecular weight (Mw) of the polyfunctional block copolymer may be in the range of 500 to 20,000. For example, the weight average molecular weight (Mw) of the polyfunctional block copolymer may be in the range of 1,000 to 20,000, or 1,000 to 10,000. When the weight average molecular weight (Mw) of the polyfunctional block copolymer is within the above range, the length of the block copolymer itself is appropriate so that the polymer may not be brittle after crosslinking, and a lithium metal electrode that does not use a solvent It may be easy to control the viscosity and thickness during coating.

The weight ratio of the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer may be in the range of 1:100 to 100:1. For example, the weight ratio of the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer may be in the range of 1:10 to 10:1. For example, the weight ratio of the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer may be in the range of 1:5 to 5:1. In the above range, it is possible to maintain an amorphous state by controlling the crystallinity of the polymer, and to improve ionic conductivity and electrochemical properties.

In addition to the polyfunctional block copolymer, other monomers or polymers having a similar structure may be mixed and used. Such other monomers or polymers include, for example, Dipentaerythritol penta-/hexa-acrylate, Glycerol propoxylate triacrylate, di(trimethylolpropane). ) tetraacrylate (Di (trimethylolpropane) tetraacrylate), trimethylolpropane ethoxylate triacrylate, poly (ethylene glycol) methyl ether acrylate (Poly (ethylene glycol) methyl ether acrylate), etc.; One or more may be used therefrom, but the present invention is not limited thereto.

The lithium salt serves to secure an ion conduction path of the organic-inorganic composite solid polymer electrolyte. The lithium salt may be used without limitation as long as it is commonly used in the art. For example, as a lithium salt, LiSCN, LiN(CN) ₂ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiC(CF ₃ SO ₂ ) ₃ , LiN(SO ₂ C ₂ F _{5 )} ) ₂ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ F) ₂ , LiSbF ₆ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (CF ₃ ) ₃ and LiB(C ₂ O ₄ ) ₂ in It may include one or more selected, but is not limited thereto.

The content of the lithium salt included in the organic-inorganic composite solid polymer electrolyte is not particularly limited, but may be, for example, 1 wt% to 50 wt% based on the total weight of the copolymer and lithium salt excluding the inorganic lithium ion conductor. For example, the content of the lithium salt may be 5 wt% to 50 wt%, specifically 10 wt% to 30 wt%, based on the total weight of the copolymer and the lithium salt. In the above range, lithium ion mobility and ion conductivity may be excellent.

The organic-inorganic composite solid polymer electrolyte comprises a lithium salt and a copolymer of an inorganic lithium ion conductor as an inorganic material, and a crosslinkable precursor comprising a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer as an organic material. It is possible to maintain an amorphous state by controlling the crystallinity, and to improve ionic conductivity and electrochemical properties. In addition, an organic-inorganic composite organic-inorganic composite solid polymer electrolyte membrane having excellent mechanical properties can be manufactured by using a small amount of organic material by improving the mechanical and elastomeric properties of the copolymer itself with the organic-inorganic composite cross-linked structure.

The organic-inorganic composite solid polymer electrolyte can be used as an all-solid electrolyte that does not use a liquid in the form of a membrane, and has improved ionic conductivity, mechanical properties, and electrochemical stability compared to conventional polymer electrolytes, and in particular 10 ^-4 S/cm or higher. It may have room temperature ionic conductivity. The ionic conductivity (σ) of the organic-inorganic composite solid polymer electrolyte may be 4×10 ⁻⁴ S/cm to 6×10 ⁻⁴ S/cm at room temperature, 25°C to 70°C.

The organic-inorganic composite solid polymer electrolyte may be directly coated on a free standing film or lithium metal electrode to minimize the interface between the lithium metal electrode and the solid polymer electrolyte.

As described above, the organic-inorganic composite solid polymer electrolyte has excellent ionic conductivity and mechanical strength, and can implement an electrolyte membrane that can be used in electrochemical devices such as high-density and high-energy lithium secondary batteries using lithium metal electrodes. In addition, there is no leakage by using the organic-inorganic composite solid polymer electrolyte, there is no electrochemical side reaction that occurs at the negative electrode and the positive electrode, and unlike an electrolyte using a liquid electrolyte, there is no electrolyte decomposition reaction, and battery characteristics can be improved and stability can be secured. .

An integrated electrode structure according to an embodiment,

lithium metal electrode; and

and the above-described organic-inorganic composite solid polymer electrolyte disposed on the lithium metal electrode.

The thickness of the lithium metal electrode may be 100 μm or less, for example, 80 μm or less, or 50 μm or less, or 30 μm or less, or 20 μm or less. According to another embodiment, the thickness of the lithium metal electrode may be 0.1 to 60㎛. Specifically, the thickness of the lithium metal electrode may be 1 to 25 μm, for example, 5 to 20 μm.

The organic-inorganic composite solid polymer electrolyte described above is disposed on the lithium metal electrode to be integrated with the lithium metal electrode. Since the organic-inorganic composite solid polymer electrolyte has high ionic conductivity and mechanical strength even at room temperature and high temperature, the performance of the lithium metal electrode can be improved.

An electrochemical device according to an embodiment includes the organic-inorganic composite solid polymer electrolyte.

이상의 온도에서도 전지의 특성을 유지하며, 이와 같은 고온에 있어서도 모든 전자 제품의 작동을 가능하게 할 수 있다.The electrochemical device has excellent safety and high energy density by using the organic-inorganic composite solid polymer electrolyte, 60

The characteristics of the battery are maintained even at an above temperature, and it is possible to operate all electronic products even at such a high temperature.

The electrochemical device may be a lithium secondary battery such as a lithium ion battery, a lithium polymer battery, a lithium air battery, or a lithium all-solid-state battery.

The electrochemical device to which the organic-inorganic composite solid polymer electrolyte is applied is suitable for applications requiring high-capacity, high-output and high-temperature operation, such as electric vehicles, in addition to the existing uses for mobile phones and portable computers. , a fuel cell, a supercapacitor, etc. can be combined to be used in a hybrid vehicle. In addition, the electrochemical device may be used in all other applications requiring high output, high voltage and high temperature driving.

Hereinafter, a method for manufacturing an organic-inorganic composite solid polymer electrolyte according to an exemplary embodiment will be described.

A method for producing an organic-inorganic composite solid polymer electrolyte according to an embodiment,

Preparing an inorganic lithium ion conductor, a crosslinkable precursor including a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer, and a precursor mixture including a lithium salt; and

and applying and curing the precursor mixture in the form of a film.

The conventional inorganic solid electrolyte is generally prepared in the form of a pellet by applying a pressure of 1,0 MPa or more to an inorganic material, such as LLZO, but the organic-inorganic composite solid polymer electrolyte according to an embodiment is an inorganic lithium ion conductor with a polymer without applying pressure. It is possible to prepare an organic-inorganic composite solid polymer electrolyte in the form of a film through complexation.

The inorganic lithium ion conductor, the crosslinkable precursor including the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer, and the lithium salt are as described above.

The precursor mixture may further include a crosslinking agent, a photoinitiator, and the like to help crosslink the crosslinkable precursor. The content of the crosslinking agent, photoinitiator, etc. may be in a conventional range, for example, may be used in the range of 1 to 5 parts by weight based on 100 parts by weight of the crosslinkable precursor.

According to an embodiment, the precursor mixture may further include an initiator to form a copolymer having a crosslinked structure with the crosslinking agent. The initiator is, for example, a peroxide (-OO-)-based benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, cumyl hydroperoxide, etc. or an azo compound (-N = N Thermal initiators such as -) series azobisisobutyronitrile and azobisisovaleronitrile may be used.

There are various methods of mixing precursor materials such as inorganic lithium ion conductors, crosslinkable precursors and lithium salts, for example, ball milling, mortar and pestel, or ultrasonic homogenizer. ) may be mixed using a method such as mixing, and there is no particular limitation.

When the precursor mixture including the inorganic lithium ion conductor, the crosslinkable precursor, and the lithium salt is prepared, the precursor mixture is applied in the form of a film and cured to form an organic-inorganic composite solid polymer electrolyte. The precursor mixture may be applied in the form of a film without using a solvent, including the crosslinkable precursor, an optional initiator, and a lithium salt.

A method of applying the precursor mixture in the form of a film is various and is not particularly limited. For example, the precursor mixture may be injected between two glass plates, and a certain pressure may be applied to the glass plates using a clamp to enable control of the thickness of the electrolyte membrane. As another example, the precursor mixture may be directly coated on the lithium metal electrode using an application device such as spin coating to form a thin film having a predetermined thickness.

In the process of applying the precursor mixture, the coating process may be performed using equipment such as a doctor blade, drop casting, and a glass plate pressing method.

As a method of curing the precursor mixture, a curing method using UV, heat, or high energy radiation (electron beam, γ-ray) may be used. According to an embodiment, the organic-inorganic composite solid polymer electrolyte may be prepared by directly irradiating the precursor mixture with UV (365 nm) or thermal polymerization and crosslinking at about 60°C.

Through the above process, an organic-inorganic composite solid polymer electrolyte membrane in the form of a monolith can be manufactured.

Exemplary embodiments are described in more detail through the following examples and comparative examples. However, the examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Example 1

As an inorganic lithium ion conductor, 5 g of garnet-type Al-doped LLZO (Ampcera Inc, Li ₇ Al _x La ₃ Zr ₂ O ₁₂ , particle size: ~500 nm) and Diurethane dimethacrylate (DUDMA) of Formula 1 (Sigma-Aldrich, 470.56/ mol) 1 g and 0.5 g of Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) diacrylate (PPG-b-PEG) (Sigma-Aldrich, average Mn ~1200) of Formula 2 above After mixing for 20 minutes using a mortar and pestle, 0.65 g of lithium salt LiFSI (lithium bis(fluorosulfonyl)imide) was added to the vial and mixed again. An initiator BEE (Benzoin ethyl ether, Sigma-Aldrich, 240.30 g/mol) was added to the mixed mixture in an amount of 3% based on the total weight of the monomer, and mixed again to prepare a composite solid electrolyte precursor mixture.

0.2 g of the composite solid electrolyte precursor mixture was placed on a glass plate, covered with another prepared glass plate, and then irradiated with 365 nm UV for 50 seconds to prepare an organic-inorganic composite solid polymer electrolyte membrane having a thickness of 30-50 μm.

Example 2

An organic-inorganic composite solid polymer electrolyte membrane was prepared in the same manner as in Example 1, except that in Example 1, the contents of LLZO, DUDMA, and PPG-b-PEG were adjusted to 3 g, 1 g, and 0.5 g, respectively.

Example 3

An organic-inorganic composite solid polymer electrolyte membrane was prepared in the same manner as in Example 1, except that in Example 1, the contents of LLZO, DUDMA, and PPG-b-PEG were adjusted to 2 g, 1 g, and 0.5 g, respectively.

Comparative Example 1

An organic-inorganic composite solid polymer electrolyte membrane was prepared in the same manner as in Example 1, except that in Example 1, the contents of DUDMA and PPG-b-PEG were adjusted to 4 g and 2 g, respectively, without using LLZO.

Evaluation Example 1: Ion conductivity evaluation

The ionic conductivity of the organic-inorganic composite solid polymer electrolyte membranes prepared in Examples 1-3 and Comparative Example 1 was measured, and the results are shown in Table 1 and FIG. 1 below. Ion conductivity is measured using Solatron 1260A Impedance/Gain-Phase Analyzer with a Solatron 1260A Impedance/Gain-Phase Analyzer after placing the sample between the sus disks using ^two sus disks with an area of 1 cm 2 did.

Example 1 Example 2 Example 3 Comparative Example 1 LLZO/DUDMA/PPG-b-PEG 5g/1g/0.5g 3g/1g/0.5g 2g/1g/0.5g 0g/4g/2g Room temperature ionic conductivity 4.24x10 ^-4 2.93x10 ^-4 2.91x10 ^-4 1.23x10 ^-5

As shown in Table 1, the organic-inorganic composite solid polymer electrolyte membranes prepared in Examples 1 to 3 and Comparative Example 1 showed a difference in ionic conductivity depending on the content ratio of LLZO, and at room temperature, 10 ^-4 S/cm or more. High ionic conductivity was measured. On the other hand, the ionic conductivity of pure organic-inorganic composite solid polymer electrolyte without inorganic lithium ion conductor LLZO ^{is relatively high at 10 -5} S/cm at room temperature, but it has lower properties compared to organic-inorganic composite solid polymer electrolyte membrane containing LLZO. have. The state of the organic-inorganic composite solid polymer electrolyte membrane after the ionic conductivity measurement was good with no significant change.

Evaluation Example 2: Ion conductivity evaluation according to temperature

Ion conductivity according to temperature change was measured for the organic-inorganic composite solid polymer electrolyte membranes prepared in Examples 1 to 3 and Comparative Example 1, and the results are shown in Table 2 and FIG. 2 below.

Temperature Example 1 Example 2 Example 3 Comparative Example 1 25℃ 4.24x10 ^-4 2.93x10 ^-4 2.19x10 ^-4 1.23x10 ^-5 40℃ 4.90 x10 ^-4 3.24 x10 ^-4 2.95 x10 ^-4 7.1 x10 ^-5 50℃ 5.60 x10 ^-4 3.37 x10 ^-4 3.22 x10 ^-4 8.4 x10 ^-5 70℃ 6.15 x10 ^-4 4.17x10 ^-4 3.51 x10 ^-4 1.71 x10 ^-4

As shown in Table 2 and FIG. 2, the ionic conductivity of the LLZO composite organic-inorganic composite solid polymer electrolyte of Example 1 was 6.15×10 ⁻⁴ S/cm at 70° C., indicating a level of ionic conductivity applicable to a relatively battery. , the organic-inorganic composite solid polymer electrolyte membrane without LLZO showed lower ionic conductivity compared to the composite electrolyte including LLZO ^{at ~10 -5 S/cm even at 50 ° C. In this case, an oligomer or other} Additives must be added to achieve a level applicable to the battery.

In the case of Examples 1 to 3, all of them ^{showed low -10 -4} S/cm ionic conductivity at the initial room temperature, but as the temperature increased, the activation energy of the organic-inorganic composite solid polymer electrolyte membrane itself increased, resulting in ion hopping. and diffusion become active, and it is thought that ion conductivity also increases.

From the above results, compared to the solid composite polymer electrolyte prepared using PEO, PVDF or PEGDMA, etc., which are widely used as polymers for solid electrolytes, as the main chain, the composite solid electrolyte prepared by applying the polymer matrix containing the polyurethane group applied to the present invention In this case, it has excellent ionic conductivity at room temperature and high temperature. In particular, it is possible to manufacture a composite electrolyte membrane by mixing a small amount of polymer and an inorganic lithium ion conductor. It can be seen that the excellent mechanical stability properties of

In the above, the preferred embodiments according to the present invention have been described with reference to the drawings and examples, but these are merely exemplary, and various modifications and equivalent other embodiments are possible by those skilled in the art. will be able to understand Accordingly, the protection scope of the present invention should be defined by the appended claims.

Claims (23)

inorganic lithium ion conductor;
a copolymer of a crosslinkable precursor comprising a urethane group-containing polyfunctional acrylic monomer and a polyfunctional block copolymer; and
Lithium salt;
The polyfunctional block copolymer is an organic-inorganic composite solid polymer electrolyte including a diblock copolymer or a triblock copolymer including a (meth)acrylate group at both ends, and a polyethylene oxide repeating unit and a polypropylene oxide repeating unit. . According to claim 1,
The inorganic lithium ion conductor is a garnet-type compound, an Argyrodite-type compound, a lithium super-ion-conductor (LISICON) compound, a Na super ionic conductor-like (NASICON) compound, lithium nitride (Li nitride), At least one organic-inorganic composite solid polymer electrolyte selected from the group consisting of lithium hydride, perovskite, lithium halide, and sulfide-based compounds . According to claim 1,
The inorganic lithium ion conductor is Garnet-based ceramics Li _3+x La ₃ M ₂ O ₁₂ (0≤x≤5, M = W, Ta, Te, Nb, and Zr), doped garnet (Garnet) ) based ceramics Li _7-3x M' _x La ₃ M ₂ O ₁₂ (0<x≤1, at least one of MW, Ta, Te, Nb, and Zr, and M' = Al, Ga, Nb, Ta, Fe , Zn, Y, Sm and Gd), Li _1+x+y Al _x Ti _2-x Si _y P _3-y O ₁₂ (0<x<2, 0≤y<3), BaTiO ₃ , Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT)(O≤x<1, O≤y<1),Pb(Mg _1/3 Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ ,0<x<2,0<y<3) , lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0<x<2, 0<y<1, 0<z<3), Li _1+x+y (Al, Ga) _x ( Ti, Ge) _2-x Si _y P _3-y O ₁₂ (O≤x≤1, O≤y≤1), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0<x<2, 0<y <3), lithium germanium thiophosphate (LixGeyPzSw, 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li _x N _y , 0 <x<4) , 0<y<2), SiS ₂ (Li _x Si _y S _z , 0≤<3,0<y<2, 0<z<4) series glass, P ₂ S ₅ (Li _x P _y S _z , 0≤x<3, 0<y<3, 0<z<7) series glass, Li _3x La _2/3-x TiO ₃ (0≤x≤1/6), Li ₇ La ₃ Zr ₂ O ₁₂ , Li _1+y Al _y Ti _2-y (PO ₄ ) ₃ (0≤y≤1) and Li _1+z Al _z Ge _2-z (PO ₄ ) ₃ (0≤z≤1), Li ₂ O, LiF, LiOH, Li ₂ C O ₃ , LiAlO ₂ , Li ₂ O-Al ₂ O ₃ -SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ ceramics, Li ₁₀ GeP ₂ S ₁₂ , Li _3.25 Ge _0.25 P _0.75 S ₄ , Li ₃ PS ₄ , Li ₆ PS ₅ Br , Li ₆ PS ₅ Cl , Li ₇ PS ₅ , Li ₆ PS ₅ I, Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ , LiTi ₂ (PO ₄ ) ₃ , LiGe ₂ (PO _{4 )} ) ₃ , LiHf ₂ (PO ₄ ) ₃ , LiZr ₂ (PO ₄ ) ₃ , Li ₂ NH ₂ , Li ₃ (NH ₂ ) ₂ I, LiBH ₄ , LiAlH ₄ , LiNH ₂ , Li _0.34 La _0.51 TiO _2.94 , LiSr ₂ Ti ₂ NbO ₉ , Li _0.06 La _0.66 Ti _0.93 Al _0.03 O ₃ , Li _0.34 Nd _0.55 TiO ₃ , Li ₂ CdCl ₄ , Li ₂ MgCl ₄ , Li ₂ ZnI ₄ , Li ₂ CdI ₄ , Li _4.9 Ga _0.5+δ La ₃ Zr _1.7 W _0.3 O ₁₂ (0≤δ<1.6), Li _4.9 Ga _0.5+δ La ₃ Zr _1.7 W _0.3 O ₁₂ (1.7≤δ≤2.5), Li _5.39 Ga _0.5+δ La ₃ Zr _1.7 W _0.3 O ₁₂ (0≤δ≤1.11), lithium phosphorous sulfide (Li ₃ PS ₄ ), lithium tin sulfide (Li ₄ SnS ₄ ), lithium phosphorous sulfur chloride iodide (Li ₆ PS ₅ Cl _0.9 I _0.1 ), lithium tin phosphorus sulfide (Li ₁₀ SnP ₂ S ₁₂ ), Li ₂ S, Li ₂ SP ₂ S ₅ , Li ₂ S-SiS ₂ , Li ₂ S-GeS ₂ , Li ₂ SB ₂ S ₅ , and Li ₂ S-Al ₂ S ₅ containing at least one selected from the group consisting of organic-inorganic composite solid polymer electrolyte. According to claim 1,
The inorganic lithium ion conductor is an organic-inorganic composite solid polymer electrolyte comprising garnet-type ceramics represented by the following Chemical Formula 3 or aluminum-doped ceramics represented by the following Chemical Formula 4:
[Formula 3]
Li _x La _y Zr _z O ₁₂
In the above formula, 6<x<9, 2<y<4, and 1<z<3.
[Formula 4]
Li _x La _y Zr _z Al _w O ₁₂
In the above formula, 5<x<9, 2<y<4, 1<z<3, and 0<w<l. According to claim 1,
An organic-inorganic composite solid polymer electrolyte having an average particle size of the inorganic lithium ion conductor in the range of 10 nm to 30 μm. According to claim 1,
The content of the inorganic lithium ion conductor is 30 to 90% by weight based on the total weight of the inorganic lithium ion conductor and the copolymer organic-inorganic composite solid polymer electrolyte. According to claim 1,
The urethane group-containing polyfunctional acrylic monomer is an organic-inorganic composite solid polymer electrolyte comprising diurethane dimethacrylate, diurethane diacrylate, or a combination thereof. According to claim 1,
The urethane group-containing polyfunctional acrylic monomer is an organic-inorganic composite solid polymer electrolyte comprising diurethane dimethacrylate represented by the following Chemical Formula 1:
[Formula 1]

In the above formula, each R is independently a hydrogen atom or a C1-C3 alkyl group. delete According to claim 1,
The polyfunctional block copolymer is an organic-inorganic composite solid polymer electrolyte comprising a polymer represented by the following Chemical Formula 2:
[Formula 2]

In the above formula, x, y, and z are each independently an integer of 1 to 50. According to claim 1,
An organic-inorganic composite solid polymer electrolyte having a weight average molecular weight (Mw) in the range of 500 to 20,000 of the polyfunctional block copolymer. According to claim 1,
The weight ratio of the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer is in the range of 1:100 to 100:1 organic-inorganic composite solid polymer electrolyte. According to claim 1,
The weight ratio of the urethane group-containing polyfunctional acrylic monomer and the polyfunctional block copolymer is in the range of 1:10 to 10:1. According to claim 1,
The lithium salt is LiSCN, LiN(CN) ₂ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiC(CF ₃ SO ₂ ) ₃ , LiN(SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF ₃ ) ₂ , LiN(SO ₂ F) ₂ , LiSbF ₆ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , LiPF ₃ (CF ₃ ) ₃ and LiB(C ₂ O ₄ ) ₂ at least one selected from An organic-inorganic composite solid polymer electrolyte comprising. According to claim 1,
Among the total weight of the copolymer and the lithium salt, the content of the lithium salt is 1 wt% to 50 wt% organic-inorganic composite solid polymer electrolyte. lithium metal electrode; and
an organic-inorganic composite solid polymer electrolyte according to any one of claims 1 to 8 and 10 to 15, disposed on the lithium metal electrode;
An integrated electrode structure comprising a. An electrochemical device comprising the organic-inorganic composite solid polymer electrolyte according to any one of claims 1 to 8 and 10 to 15. preparing a crosslinkable precursor including an inorganic lithium ion conductor, a polyfunctional acrylic monomer containing a urethane group, and a polyfunctional block copolymer, and a precursor mixture including a lithium salt; and
applying and curing the precursor mixture in the form of a film;
In claim 1, wherein the polyfunctional block copolymer comprises a diblock copolymer or a triblock copolymer comprising an acrylate group at both ends, and a polyethylene oxide repeating unit and a polypropylene oxide repeating unit. A method for producing an organic-inorganic composite solid polymer electrolyte according to the present invention. 19. The method of claim 18,
The urethane group-containing polyfunctional acrylic monomer is a method for producing an organic-inorganic composite solid polymer electrolyte comprising diurethane dimethacrylate, diurethane diacrylate, or a combination thereof. 19. The method of claim 18,
The urethane group-containing polyfunctional acrylic monomer is a method for producing an organic-inorganic composite solid polymer electrolyte comprising diurethane dimethacrylate represented by the following Chemical Formula 1:
[Formula 1]

In the above formula, each R is independently a hydrogen atom or a C1-C3 alkyl group. delete 19. The method of claim 18,
The polyfunctional block copolymer is a method for producing an organic-inorganic composite solid polymer electrolyte comprising a polymer represented by the following Chemical Formula 2:
[Formula 2]

In the above formula, x, y, and z are each independently an integer of 1 to 50. 19. The method of claim 18,
The method for producing an organic-inorganic composite solid polymer electrolyte wherein the curing is performed using UV, heat or high energy radiation.

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