Title of invention: solid electrolyte membrane and all-solid battery including the same
Technical field
[One]
This application claims priority based on Korean Patent Application No. 10-2018-0069240 filed on June 15, 2018 and Korean Patent Application No. 10-2018-0167864 filed on December 21, 2018. The present invention relates to a solid electrolyte membrane for an all-solid battery and a battery including the same. In addition, the present invention relates to an all-solid-state battery containing lithium metal as a negative electrode active material.
[2]
Background
[3]
A lithium ion battery using a liquid electrolyte has a structure in which a negative electrode and a positive electrode are partitioned by a separator, so if the separator is damaged by deformation or external impact, a short circuit may occur, which may lead to a risk of overheating or explosion. Therefore, it can be said that the development of a solid electrolyte that can secure safety in the field of lithium ion secondary batteries is a very important task.
[4]
A lithium secondary battery using a solid electrolyte has advantages in that the safety of the battery is increased, leakage of an electrolyte solution can be prevented, so that the reliability of the battery is improved, and it is easy to manufacture a thin-type battery. In addition, since lithium metal can be used as a negative electrode, energy density can be improved. Accordingly, it is expected to be applied to a high-capacity secondary battery for an electric vehicle as well as a small secondary battery, thus attracting attention as a next generation battery.
[5]
As the solid electrolyte, a polymer material of an ion conductive material or an inorganic material of oxide or sulfide having ion conductive properties may be used, and a hybrid material in which a polymer material and an inorganic material are mixed has also been proposed.
[6]
On the other hand, when lithium metal is used as the negative electrode active material, there is a problem that lithium dendrites grow from the surface of the negative electrode, and when the grown lithium dendrites contact the positive electrode, a short circuit of the battery is caused. 1 is a schematic diagram of such a conventional all-solid-state battery. In the all-solid-state battery, the solid electrolyte membrane serves as an electrical insulator for the positive and negative electrodes instead of the separator. However, when a polymer material is used as the solid electrolyte, the solid electrolyte membrane may be damaged by the growth of lithium dendrites. 1 shows a conventional all-solid battery using a solid electrolyte, and schematically shows a mechanism for generating a short circuit according to the growth of a lithium dendrite 14a. In the all-solid-state battery of FIG. 1, a positive electrode active material layer 12 is formed on a surface of a current collector 11, and the positive electrode active material layer is stacked via a negative electrode 14 and a solid electrolyte layer 13. In such an all-solid-state battery, lithium dendrites 14a may grow in a vertical direction at the negative electrode depending on the use of the battery, and the solid electrolyte layer 13 may be damaged by lithium dendrites. (short circuit) may occur. In addition, the inorganic solid electrolyte is generally formed in a layered structure by integrating particulate ion-conducting inorganic materials, and contains a large number of pores due to interstitial volumes between particles. Accordingly, lithium dendrites may grow into the space provided by the pores, and a short circuit may occur when the lithium dendrites grown through the pores come into contact with the positive electrode. Accordingly, there is a need to develop an electrolyte membrane for an all-solid battery capable of inhibiting the growth of lithium dendrites.
[7]
Detailed description of the invention
Technical challenge
[8]
An object of the present invention is to provide a solid electrolyte membrane for an all-solid battery in which the growth of lithium dendrites is suppressed in order to solve the above-described problems. In addition, another object of the present invention is to provide an all-solid-state battery containing lithium metal as a negative electrode active material. Other objects and advantages of the present invention will be understood by the following description. On the other hand, it will be readily appreciated that the objects and advantages of the present invention can be realized by means or methods described in the claims, and combinations thereof.
[9]
Means of solving the task
[10]
The present invention relates to a solid electrolyte membrane for an all-solid battery to solve the above technical problem. The first aspect of the present invention relates to the electrolyte membrane, wherein the electrolyte membrane has an ionic conductivity of 1x10 -7 S/cm or more, and the solid electrolyte membrane is an inhibitory layer comprising a dendrite growth inhibitory material (a). Including one or more, wherein the dendrite growth inhibiting material (a) is derived from any one of (a1) metal(s) having a lower ionization tendency than lithium and (a2) alloy(s) of two or more of the metals It is contained in the suppression layer in the form of at least one of salts and ions thereof.
[11]
In a second aspect of the present invention, in the first aspect, the suppression layer is patterned including a plurality of pattern units including a suppression material, and the pattern units are regularly or irregularly distributed in the suppression layer.
[12]
In a third aspect of the present invention, in the second aspect, the inhibition layer comprises a dendrite growth inhibiting material (a) and a polymer copolymer in which the inhibiting material is chemically bonded, and self-assembly of the polymer copolymer ( Self-assembly) has a fine pattern derived from, the polymer copolymer contains a functional group capable of chemical bonding with the inhibitory substance, and the inhibitory substance is bonded to the polymer copolymer through the functional group.
[13]
In a fourth aspect of the present invention, in at least one of the second and third aspects, the suppression layer has a shape in which micelles are aligned according to a hexagonal dense structure by self-assembly of the polymer copolymer.
[14]
In a fifth aspect of the present invention, in at least one of the second to fourth aspects, the functional group includes at least one of ether and amine.
[15]
The sixth aspect of the present invention is a polystyrene-block-poly(2-vinylpyridine) copolymer, polystyrene-block-poly(4-vinylpyridine) copolymer, polystyrene-block-poly(2-vinylpyridine) copolymer, polystyrene-block-poly(2-vinylpyridine) copolymer, poly It contains at least one selected from (1,4-isoprene)-block-polystyrene-block-poly(2-vinylpyridine) copolymer and polystyrene-block-poly(ethylene oxide) copolymer.
[16]
The seventh aspect of the present invention is in at least one of the first to sixth aspects, wherein the metal is K, Sr, Ca, Na, Mg, Be, Al, Mn, Zn, Cr(+3), Fe, It includes at least one selected from the group consisting of Cd, Co, Ni, Sn, Pb, Cu, Hg, Ag, Pd, Ir, Pt(+2), Au, and Pt(+4).
[17]
In an eighth aspect of the present invention, according to at least one of the first to seventh aspects, the inhibitory material includes at least one selected from the group consisting of Au and Pt.
[18]
The ninth aspect of the present invention is according to at least one of the first to eighth aspects, wherein the metal salt is chloride, iodide, cyanide, boride, sulfide. ), hydrate, phosphite, and chloride hydrate.
[19]
The tenth aspect of the present invention is according to at least one of the first to ninth aspects, wherein the solid electrolyte membrane includes two or more solid electrolyte layers and one or more suppression layers, and the suppression layer is disposed between the solid electrolyte layers. will be.
[20]
In an eleventh aspect of the present invention, in the tenth aspect, the solid electrolyte membrane includes a first solid electrolyte layer, a suppression layer, and a second solid electrolyte layer sequentially stacked.
[21]
A twelfth aspect of the present invention is in at least one of the tenth and eleventh aspects, wherein at least one of the two or more solid electrolyte layers contains an inhibitory material, and the content of the inhibitory material in each solid electrolyte layer (% by weight) Silver is lower than the content (% by weight) of the inhibitory substance contained in the suppression layer.
[22]
In a thirteenth aspect of the present invention, according to at least one of the first to twelfth aspects, the solid electrolyte membrane comprises an ion conductive solid electrolyte material, and the ion conductive solid electrolyte material is a polymer solid electrolyte, an inorganic solid electrolyte, or It includes a mixture of both.
[23]
In a fourteenth aspect of the present invention, in the thirteenth aspect, the polymer solid electrolyte includes a polymer resin and a solvated lithium salt.
[24]
The fifteenth aspect of the present invention relates to an electrochemical device, wherein the electrochemical device is an all-solid-state battery comprising a negative electrode, a positive electrode, and a solid electrolyte membrane interposed between the negative electrode and the positive electrode, and the negative electrode includes lithium metal, The solid electrolyte membrane is according to at least one of the first to fourteenth aspects.
[25]
A sixteenth aspect of the present invention is the fifteenth aspect, wherein the solid electrolyte membrane is a first solid electrolyte layer, a suppression layer, and a second solid electrolyte layer are sequentially stacked, and the first solid electrolyte layer is an inhibitory material (a ), and the inhibitory material is derived from any one of (a1) metal(s) having a lower ionization tendency than lithium and (a2) alloy(s) of two or more of the metals.
[26]
Effects of the Invention
[27]
The solid electrolyte membrane for an all-solid battery according to the present invention has an effect of suppressing the growth of lithium dendrites by ionizing lithium precipitated as a metal, since the solid electrolyte membrane for an all-solid-state battery is provided with a suppression layer containing an inhibitory material that suppresses the growth of lithium dendrites. Therefore, in the case of using lithium metal as a negative electrode in the all-solid battery including the solid electrolyte membrane, there is an effect of delaying and/or suppressing the growth of lithium dendrites, thereby effectively preventing an electrical short due to the growth of the dendrites. In addition, the suppression layer may have a fine pattern such as formed by self-assembly of a polymer material, so that it effectively suppresses the growth of lithium dendrites and does not lower ionic conductivity.
[28]
Brief description of the drawing
[29]
The drawings appended to the present specification illustrate preferred embodiments of the present invention, and serve to better understand the technical spirit of the present invention together with the content of the present invention, so the present invention is limited to the matters described in such drawings. Is not interpreted. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in the present specification may be exaggerated to emphasize a clearer description.
[30]
1 is a schematic diagram of a problem in which a short circuit is caused by growth of lithium dendrites from a negative electrode in a conventional all-solid battery.
[31]
2 schematically shows a solid electrolyte membrane according to an embodiment of the present invention.
[32]
3 is a schematic diagram of an all-solid-state battery according to an embodiment of the present invention, and schematically shows a reaction in which the growth of lithium dendrite is inhibited in a growth inhibitory material included in the all-solid electrolyte membrane.
[33]
4 is a schematic diagram of a solid electrolyte membrane including a patterned suppression layer.
[34]
5 shows an AFM image of the suppression layer prepared in Example 5.
[35]
6 and 7 are schematic cross-sectional views of a solid electrolyte membrane according to an embodiment of the present invention.
[36]
Mode for carrying out the invention
[37]
Hereinafter, embodiments of the present invention will be described in detail. Prior to this, terms or words used in the specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention. Therefore, the configuration described in the embodiments described in the present specification is only the most preferred embodiment of the present invention, and does not represent all the technical spirit of the present invention, and various equivalents and equivalents that can replace them at the time of the present application It should be understood that there may be variations.
[38]
In the entire specification of the present application, when a certain part "includes" a certain constituent element, it means that other constituent elements may be further included rather than excluding other constituent elements unless otherwise stated.
[39]
[40]
In addition, the terms "about" and "substantially" used throughout the specification of the present application are used as a meaning at or close to the numerical value when a manufacturing and material tolerance specific to the stated meaning is presented to aid understanding of the present application. In order to prevent unreasonable use by unscrupulous infringers of the stated disclosures, either exact or absolute figures are used.
[41]
[42]
In the entire specification of the present application, the description of "A and/or B" means "A or B or both".
[43]
[44]
Certain terms used in the detailed description that follow are for convenience and are not limiting. The words'right','left','top' and'bottom' indicate directions in the drawings to which reference is made. The words'inwardly' and'outwardly' refer to a direction towards or away from the geometric center of the specified device, system and members, respectively. 'Forward','rear','upward','downward' and related words and phrases represent positions and orientations in the drawings to which reference is made and should not be limited. These terms include the words listed above, their derivatives and words of similar meaning.
[45]
[46]
The present invention relates to an electrolyte membrane for a secondary battery and a secondary battery including the electrolyte membrane. In the present invention, the secondary battery may be a lithium ion secondary battery. In one embodiment of the present invention, the secondary battery is an all-solid battery using a solid electrolyte as an electrolyte, and the battery may include lithium metal as a negative active material.
[47]
[48]
2 is a schematic view of a solid electrolyte membrane according to an embodiment of the present invention, and a solid electrolyte membrane formed by sequentially stacking a second solid electrolyte layer 131, a suppression layer 132, and a first solid electrolyte layer 133 It is a schematic diagram of (130). The configuration of the present invention will be described in more detail with reference to FIG. 2.
[49]
[50]
(1) solid electrolyte membrane
[51]
The solid electrolyte membrane according to the present invention includes a suppression layer, and the solid electrolyte membrane may be applied as an ion conductive electrolyte to an all-solid battery that does not use a liquid electrolyte, for example. In one embodiment of the present invention, the solid electrolyte membrane may include two or more solid electrolyte layers, and a suppression layer may be interposed between each solid electrolyte layer. In the present invention, each of the solid electrolyte layers includes an ion conductive solid electrolyte material, and the suppression layer includes a dendrite growth inhibiting material.
[52]
In the present invention, the solid electrolyte membrane includes a suppression layer, electrically insulates the anode and the cathode, and provides an ion conduction path between the anode and the cathode, and has an ionic conductivity of 1x10 -7 S/ in the range of 25°C to 150°C. cm or more, preferably 1x10 -5 S/cm or more.
[53]
[54]
In one embodiment of the present invention, the solid electrolyte membrane may have a thickness in the range of 5 μm to 500 μm. The solid electrolyte membrane may be, for example, 10 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 100 μm or more, 200 μm or more, or 300 μm or more in terms of physical strength and shape stability. Meanwhile, in terms of ion conductivity, it may be 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 70 μm or less, or 50 μm or less. For a specific example, the thickness of the solid electrolyte membrane may be 30 μm to 100 μm or 30 μm to 50 μm.
[55]
[56]
The ion conductive solid electrolyte material may include one or more of a polymer solid electrolyte and an inorganic solid electrolyte.
[57]
In one embodiment of the present invention, the polymer solid electrolyte includes a polymer resin and a lithium salt, and is a solid polymer electrolyte in the form of a mixture of a solvated lithium salt and a polymer resin, or contains an organic solvent and a lithium salt. It may be a polymer gel electrolyte in which an organic electrolyte is contained in a polymer resin.
[58]
[59]
In one embodiment of the present invention, the solid polymer electrolyte is a polymer resin, for example, a polyether polymer, a polycarbonate polymer, an acrylate polymer, a polysiloxane polymer, a phosphazene polymer, a polyethylene derivative, an alkylene. Oxide derivatives, phosphoric acid ester polymers, poly agitation lysine (agitation lysine), polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and a mixture of two or more selected from the group consisting of a polymer containing an ionic dissociation group It may include, but is not limited thereto.
[60]
[61]
In a specific embodiment of the present invention, the solid polymer electrolyte is a polymer resin in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (pdms) and/or phosphazene is copolymerized with a comonomer in a PEO (polyethylene oxide) main chain. It may include one or a mixture of two or more selected from the group consisting of a branched copolymer, a comb-like polymer, and a crosslinked polymer resin.
[62]
[63]
In addition, in a specific embodiment of the present invention, the polymer gel electrolyte includes an organic electrolytic solution containing a lithium salt and a polymer resin, and the organic electrolytic solution may include 60 to 400 parts by weight based on the weight of the polymer resin. The polymer resin applied to the gel electrolyte is not limited to a specific component, but for example, PVC (Polyvinyl chloride), PMMA (Poly (methyl methacrylate)), polyacrylonitrile (PAN), polyvinyl fluoride It may be one or a mixture of two or more selected from the group consisting of leadene (PVdF) and polyvinylidene fluoride-hexafluoropropylene (poly(vinylidene fluoride-hexafluoropropylene: PVdF-HFP)), but is not limited thereto.
[64]
[65]
In the electrolyte of the present invention, the above lithium salt is Li as an ionizable lithium salt + X - can be represented by. In this lithium salt anion (X) is not particularly limited, F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , PF 6 - , ( CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , (SF 5 ) 3 C - , (CF 3 SO 2 ) 3 C - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 -, SCN - , (CF 3 CF 2 SO 2 ) 2 N - and the like can be given.
[66]
[67]
Meanwhile, in a specific embodiment of the present invention, the polymer solid electrolyte may further include an additional polymer gel electrolyte. The polymer gel electrolyte has excellent ionic conductivity (or 10 -4 s/m or more), has binding properties, provides a function as an electrolyte, and provides a binding force between an electrode active material and an electrode layer and a current collector. The function of the electrode binder resin to be provided can be provided.
[68]
[69]
Meanwhile, in the present invention, when a polymer material is used as an electrolyte material for the solid electrolyte layer, the solid electrolyte membrane may further include a crosslinking agent and/or an initiator when preparing the solid electrolyte layer. The crosslinking agent and/or initiator may initiate a crosslinking reaction or a polymerization reaction depending on heat, light and/or temperature conditions, and are not limited to a special component as long as it can induce crosslinking and/or polymerization of a polymer material. In one embodiment of the present invention, an organic peroxide, an organometallic reagent such as silver alkylation, an azo compound, etc. may be used as the crosslinking agent and/or initiator, but is not limited thereto.
[70]
Meanwhile, in the present invention, the inorganic solid electrolyte may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or both.
[71]
[72]
In a specific embodiment of the present invention, the sulfide-based solid electrolyte includes a sulfur atom among the electrolyte components, and is not particularly limited to specific components, and is crystalline solid electrolyte, amorphous solid electrolyte (glassy solid electrolyte), glass ceramic It may contain one or more of the solid electrolytes. Specific examples of the sulfide-based solid electrolyte include LPS-type sulfide containing sulfur and phosphorus, Li 4 - x Ge 1 - x P x S 4 (x is 0.1 to 2, specifically x is 3/4, 2/3 ), Li 10 ± 1 MP 2 X 12 (M=Ge, Si, Sn, Al, X=S, Se), Li 3.833 Sn 0.833 As 0.166 S 4 , Li 4 SnS 4, Li 3 . 25 Ge 0 .25 P 0. 75 S 4 , Li 2 S-P 2 S 5 , B 2 S 3 -Li 2 S, xLi 2 S-(100-x)P 2 S 5 (x is 70 to 80), Li 2 S-SiS 2 -Li 3 N, Li 2 S-P 2 S 5 -LiI, Li 2 S-SiS 2 -LiI, Li 2 S-B 2 S 3 -LiI, and the like, but are not limited thereto.
[73]
[74]
In a specific exemplary embodiment of the present invention, the oxide-based solid electrolyte, for example, Li 3x La 2 / 3x TiO 3 LLT system of perop Sky imide structure, such as, Li 14 Zn (GeO 4 ) 4 , such as LISICON, Li 1 . 3 Al 0 . 3 Ti 1 . 7 LATP system like (PO 4 ) 3 , (Li 1 + x Ge 2 - x Al x (PO 4 ) 3), such as LAGP-based, LiPON-based phosphate-based, and the like may be appropriately selected and used, but is not particularly limited thereto.
[75]
[76]
(2) suppression layer
[77]
The solid electrolyte membrane according to the present invention includes a suppression layer, and the suppression layer includes a lithium dendrite growth suppression material (see FIG. 2). In the suppression layer, the suppression material may be distributed evenly or in a non-uniform distribution throughout the suppression layer. In the present specification, the dendrite growth inhibitory substance may be abbreviated as an inhibitory substance.
[78]
In one embodiment of the present invention, the suppression layer may have a patterned form in a manner in which pattern units including the suppression material are regularly or irregularly arranged in the suppression layer. The pattern unit is that the suppression material is contained in a high concentration in the suppression layer, for example, a portion containing the suppression material in a concentration of 50% by weight or more, 60% by weight or more, or 70% by weight or more in 100% by weight of one pattern unit Means. The pattern unit may include only an inhibitory material or, if necessary, a mixture of an inhibitory material and a solid electrolyte material. Meanwhile, the uncoated portion that may exist between the pattern units may be filled with a solid electrolyte layer stacked on the upper and lower portions of the suppression layer (see FIG. 6) or filled with a separate solid electrolyte material (see FIG. 4). In one embodiment of the present invention, the pattern units are not limited to a special shape. Their planar shape may be linear or may be a circular or rectangular closed curve. In the case of a linear pattern, they can be formed so that they are parallel or intersected with each other. For example, the pattern unit may have a planar shape of a stripe or dot. 4 is a schematic diagram of a cross-section of a solid electrolyte membrane 330 according to an embodiment of the present invention, and shows an embodiment in which a plurality of pattern elements 332a are included in the suppression layer 332. In one embodiment of the present invention, the solid electrolyte layer is preferably less than 80%, less than 70%, less than 60% or less than 50% of the area covered with the suppression layer relative to 100 area% of its surface. When the suppression layer is formed in a manner that excessively covers the surface of the solid electrolyte layer, the ionic conduction path is rather blocked by the suppression layer, so that the ionic conductivity characteristics of the solid electrolyte membrane may be deteriorated. When the covering area of ​​the suppression layer satisfies the above range, the lithium dendrite growth suppression effect is high, and the lithium ion conductivity decrease due to the formation of the suppression layer may be prevented. However, the above-described shapes of the suppression layer and the solid electrolyte membrane are exemplary and may be applied without particular limitation as long as the structural features of the present invention can be implemented.
[79]
In the present invention, the thickness of the suppression layer may vary depending on the manufacturing method, and may be, for example, greater than 0 and less than or equal to 100 μm. As described above, when patterned by a mixture with a solid electrolyte material or the like, it may have a range of 1 μm to 100 μm, and may be formed to be 70 μm or less, 50 μm or less, or 30 μm or less within the above range. .
[80]
In one embodiment of the present invention, the inhibitory layer may be formed by adding an inhibitory substance to an appropriate solvent to prepare an inhibitory substance solution and then coating it on the surface of the solid electrolyte layer. When the suppression layer is introduced in this way, the thickness of the suppression layer can be made very thin, for example at the nanometer scale level. In addition, according to an embodiment of the present invention, the suppression layer may be coated with the solution so as to have a shape of a stripe or dot. Since it is buried by the electrolyte layer, it is possible to minimize the occurrence of separation between the upper and lower solid electrolyte layers or increase in interfacial resistance due to this. 6 is a schematic diagram showing a state in which the uncoated portion of the suppression layer 332 is filled by being filled by the first solid electrolyte layer 332 and the second solid electrolyte layer 331. When the suppression layer is formed by applying the suppression material solution as described above, the thickness of the suppression layer may be 700 nm or less, 500 or less, 300 nm or less, 100 nm or less, or 50 nm or less.
[81]
In a specific embodiment of the present invention, in addition to the method of forming a suppression layer by directly applying an inhibitory substance solution, etc. on the surface of the solid electrolyte layer, the suppression layer is patterned and formed on a separate release sheet, and then the patterned suppression layer A method of transferring the material to the solid electrolyte layer, or a method of patterning the solid electrolyte layer using lithography may be applied. Meanwhile, when a pattern is applied to the suppression layer, the suppression material may be further exposed through O 2 plasma, UV-ozone, or etching after performing the patterning process .
[82]
[83]
In addition, in a specific embodiment of the present invention, it can be achieved by applying a method of self-assembly of the polymer copolymer, and through this, very fine pattern units (micelle micelles, etc.) at the level of nanometers are uniform. It can be arranged in the suppression layer by distribution. The suppression layer formed by self-assembly of the polymer copolymer includes an inhibitory substance and a polymer copolymer, and the inhibitory substance is chemically bonded to the polymer copolymer. In the present specification, "chemically bonded" means that the inhibitory material is bonded to the polymer copolymer in a chemical manner such as ionic bonds, covalent bonds, and coordination bonds. Meanwhile, in the present specification, the dendrite growth inhibitory substance may be abbreviated and referred to as an inhibitory substance. When the suppression layer is formed by self-assembly of the polymer copolymer as described above, the thickness of the suppression layer may be 1 μm or less, 700 nm or less, 500 or less, 300 nm or less, 100 nm or less, or 50 nm or less.
[84]
[85]
In the present invention, the inhibitory substance has a lower ionization tendency than that of lithium. The inhibitory material is less reactive than lithium, that is, has a low ionization tendency. For this reason, it is possible to prevent lithium ions from being reduced and precipitated as lithium metal by the suppression material, and further, there is an effect of reducing the amount of dendrites by oxidizing the precipitated lithium to lithium ions again.
[86]
[87]
In the present invention, the inhibitory material (a) is a1) metal(s) having a lower ionization tendency than lithium; And a2) alloy(s) of two or more of metals having a lower ionization tendency than lithium; It is derived from at least any one of, and is a mixture containing at least one of salts and ions thereof, and the mixture is distributed in the suppression layer. That is, the suppression layer includes at least one of the salt of the metal, the salt of the alloy, the ions of the metal, and the ions of the alloy.
[88]
In one embodiment of the present invention, the a1) metal is K, Sr, Ca, Na, Mg, Be, Al, Mn, Zn, Cr(+3), Fe, Cd, Co, Ni, Sn, Pb, It may be one or more selected from the group consisting of Cu, Hg, Ag, Pd, Ir, Pt(+2), Au, and Pt(+4). In addition, the a2) alloy is an alloy of two or more selected among the metal components. In one embodiment of the present invention, the metal salt is, for example, chloride, iodide, cyanide, boride, sulfide, hydroxide, phosphite. ), it may be one or more of chloride hydrate. However, any form capable of reacting with the lithium metal to oxidize the lithium metal in the form of ions is not limited, and is not limited to the above form. On the other hand, in one embodiment of the present invention, the lower the ionization tendency of the inhibitory material, the higher the lithium dendrite growth inhibitory effect. Accordingly, the inhibitory material may include at least one of Au and Pt. In one embodiment of the present invention, when Au is used as the inhibitory material, HAuCl 4 · 3H 2 O in the form of a salt thereof may be added during the production of the inhibitory layer, and when Pt is used as the inhibitory substance, its H 2 PtCl 6 in the form of a salt H 2 O can be added in the production of the suppression layer.
[89]
[90]
On the other hand, in the patterning of the inhibitory material due to self-assembly of the polymer copolymer according to an embodiment of the present invention, the polymer copolymer is one containing a functional group capable of chemical bonding with the inhibitor, that is, , The inhibitory substance is bonded to the polymer copolymer through the functional group. In one embodiment of the present invention, the functional group includes oxygen or nitrogen, and includes a functional group capable of bonding with a metal salt such as ether and amine, and at least one selected from among the functional groups. I can. These functional groups are bonded by an attractive force between the (-) charge of oxygen or nitrogen and the (+) charge of metal ions in the metal salt.
[91]
[92]
Such polymer copolymers include polystyrene-block-poly (2-vinylpyridine) copolymer, polystyrene-block-poly(4-vinylpyridine) copolymer, and poly(1,4-isoprene)-block-polystyrene-block-poly(2-vinylpyridine) There are copolymers and polystyrene-block-poly(ethylene oxide) copolymers, but are not limited to special types as long as they contain the above-described functional groups and can form nanoscale fine patterns by self-assembly.
[93]
[94]
In a specific embodiment of the present invention, the suppression layer may exhibit a shape in which micelles formed by a self-assembled block copolymer are aligned according to a hexagonal dense structure. For example, when polystyrene-block-poly4vinyl pyridine is used as a block copolymer, micelles mainly containing polyvinylpyridine blocks (PVP) are arranged according to a certain rule in a matrix mainly containing polystyrene blocks (PS) by self-assembly. The suppression material bonded to the PVP block can secure a high level of uniform dispersion over the entire suppression layer according to the arrangement of these micelles. The micelle may consist of a core portion and a shell portion surrounding the surface of the core, and the inhibitory material is bonded to the core portion and/or the shell portion. 5 shows an AFM image of the suppression layer prepared in Example 5, and it can be seen that micelles are arranged and arranged in a hexagonal dense structure on the surface of the solid electrolyte layer.
[95]
[96]
7 is a schematic diagram of a cross section of a suppression layer formed by a self-assembled block copolymer and a solid electrolyte membrane including the same. Referring to this, the solid electrolyte membrane 430 has a suppression layer 432 interposed between the first solid electrolyte layer 433 and the second solid electrolyte layer 431. According to this, the micelle 432a, in particular, the core portion of the micelles is relatively thick, but the thickness between the micelles and the micelles is relatively thin. Alternatively, a matrix may not be formed between the micelles and the micelles according to process conditions, for example, depending on the speed of spin coating and the concentration of the micelle solution. Therefore, even if the suppression layer is disposed in a form that covers most of the surface of the solid electrolyte layer, lithium ions can permeate through the matrix, so that the ionic conductivity of the solid electrolyte layer can be properly maintained. There is no. In one embodiment of the present invention, the thickness of the suppression layer may be adjusted through O 2 plasma or UV-ozone treatment. In this way, ion conduction is possible, and at the same time, lithium dendrite growth is suppressed by an inhibitory material bound to the core of the micelle.
[97]
[98]
In a specific embodiment of the present invention, the size of the micelles may be 20nm to 300nm, the interval between micelles may be 10nm to 500nm.
[99]
[100]
As described above, since the electrolyte membrane according to the present invention contains an inhibitory material for inhibiting lithium growth, when applied to an all-solid battery including lithium metal as a negative electrode active material, short circuit due to lithium dendrite growth can be effectively suppressed.
[101]
[102]
(3) Structure of solid electrolyte membrane
[103]
In one embodiment of the present invention, the solid electrolyte membrane includes a suppression layer including an inhibitory material. In one embodiment of the present invention, the solid electrolyte membrane may include two or more solid electrolyte layers and one or more suppression layers, and the suppression layer may be disposed between the solid electrolyte layers. For example, the solid electrolyte membrane may have a layered structure in which a first solid electrolyte layer, a suppression layer, and a second solid electrolyte layer are sequentially stacked (see FIG. 2). Alternatively, the solid electrolyte membrane may include first, second and third solid electrolyte layers, a first suppression layer between the first and second solid electrolyte layers, and a first suppression layer between the second and third solid electrolyte layers. 2 suppression layers may be disposed. Each of the suppression layers is independent of each other in terms of shape or material, and one suppression layer may be the same as or different from the other. In addition, each of the solid electrolyte layers is independent of each other in terms of shape or material, and one solid electrolyte layer may be the same as or different from the other.
[104]
[105]
In the present invention, the solid electrolyte membrane may exhibit an ionic conductivity of 1x10 -7 S/cm or more, preferably 1x10 -5 S/cm or more, in a state in which the suppression layer is included .
[106]
[107]
The suppression layer is one in which the suppression material is contained in a higher concentration than other layers (for example, a solid electrolyte layer). For example, the suppression layer may contain a suppression material in the range of 10% by weight to 90% by weight relative to 100% by weight of the suppression layer. The content of the inhibitory substance may be 30% by weight or more, 50% by weight or more, 70% by weight or more, 80% by weight or more within the above range, and together or independently, the content is 80% by weight or less, 70% by weight or less, or 60 It may be less than or equal to weight. The concentration of the suppression material in the suppression layer may be adjusted to an appropriate range in consideration of the dendrite suppression effect, the ionic conductivity of the solid electrolyte membrane, and the manufacturing cost of the battery due to the use of a noble metal as the suppression material. On the other hand, in one embodiment of the present invention, 50% by weight or more of 100% by weight of the total suppression material included in the solid electrolyte membrane may be included in the suppression layer.
[108]
[109]
In one embodiment of the present invention, the suppression layer may further include at least one of a binder resin and an ion conductive solid electrolyte material in addition to the suppression material. The binder resin may be used without particular limitation as long as it is an electrochemically stable component having properties that aid in bonding between suppression substances and bonding between the suppression layer and other solid electrolyte layers. Non-limiting examples of such binder resins include acrylic polymers, polyvinylidene fluoride polymers, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, recycled cellulose, polyvinylpyrroly. Don, tetrafluoroethylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, and various copolymers.
[110]
In the present invention, the thickness of the suppression layer, the concentration of the suppression layer increase suppression material, the area in which the suppression layer covers the solid electrolyte layer, etc. can be appropriately adjusted in consideration of the ionic conductivity of the solid electrolyte membrane. That is, the suppression layer included in the solid electrolyte membrane is the thickness of the suppression layer, the concentration of the suppression material, and the suppression layer so that the solid electrolyte membrane can exhibit ionic conductivity of 1x10 -7 S/cm or more, preferably 1x10 -5 S/cm The covering area of ​​the solid electrolyte layer by can be adjusted to have an appropriate range.
[111]
[112]
In one embodiment of the present invention, the suppression layer may be formed by the following method. In one embodiment of the present invention, the suppression layer may be formed by applying an inhibitory substance solution mixed with a solvent and drying the inhibitory substance solution on the surface of the first solid electrolyte layer. In this case, the suppression layer may be obtained in a state coated with a very thin thickness on one surface of the first solid electrolyte layer. In this case, since only the suppression material is included in the coated suppression layer, the thickness of the suppression layer may be very thin at a nanometer scale of less than 1 µm. In another embodiment, if the suppression layer is formed in the form of a composite of the suppression material and the solid electrolyte material and/or the binder resin, it may be formed thicker than the suppression layer formed only of the suppression material.
[113]
In addition, the first and second solid electrolyte layers include an ion conductive solid electrolyte material, and may further include an inhibitory material, a binder resin, or both, if necessary. In the first and second solid electrolyte layers, the inhibitory material may be dispersed in a uniform distribution. In addition, the inhibitory material may be included in a ratio of 0% to 50% by weight of 100% by weight of the solid electrolyte layer. The content of the inhibitory material in the solid electrolyte layer may be 40% by weight or less, 30% by weight or less, 20% by weight, or 10% by weight or less within the above range.
[114]
[115]
For the suppression layer and the suppression material and the ion conductive solid electrolyte material included in the first and second solid electrolyte layers, the above description may be referred to.
[116]
[117]
Meanwhile, in a specific embodiment of the present invention, the composition of the ion conductive solid electrolyte included in the first and second solid electrolyte layers may be the same or different from each other. For example, the first layer may include an oxide-based solid electrolyte material, and the second layer may include a sulfide-based solid electrolyte material.
[118]
[119]
In one embodiment, the solid electrolyte membrane may be formed by forming a suppression layer on the surface of the first solid electrolyte layer and then forming a second solid electrolyte layer on the surface of the suppression layer. If two or more suppression layers are included, a method of forming a third solid electrolyte layer on the surface of the second solid electrolyte layer after forming the suppression layer on the surface of the second solid electrolyte layer may be prepared. In one embodiment of the present invention, in the case of manufacturing a solid electrolyte membrane including a more suppression layer or a solid electrolyte layer, a method of forming the suppression layer and the solid electrolyte layer may be repeatedly performed.
[120]
In one embodiment of the present invention, when the suppression layer is patterned, the suppression layer may be formed as a pattern layer having a convex pattern on the surface of the first solid electrolyte layer. Thereafter, a slurry for a second solid electrolyte layer may be applied to the surface of the suppression layer so that the uncoated part (the part where the suppression layer is not formed) between the patterns is buried with the second solid electrolyte. For example, suppression layer pattern elements including an suppression material are formed on the surface of the first solid electrolyte layer. Thereafter, the surface is coated with a second solid electrolyte layer to form a solid electrolyte membrane. In one embodiment of the present invention, the second solid electrolyte layer may be formed from a flowable slurry. Accordingly, the slurry is applied to the surface of the first solid electrolyte layer on which the suppression layer pattern elements are formed to fill the uncoated area between the pattern elements, and the empty space spaced apart between the suppression layer/first solid electrolyte layer/second solid electrolyte layer Can be prevented from forming.
[121]
Alternatively, the suppression layer may be formed by forming a concave pattern having a predetermined thickness from the surface of the first solid electrolyte layer and then embedding the suppression material in the concave pattern (inlay method). Thereafter, a solid electrolyte membrane may be obtained by covering the surface of the suppression layer with a second solid electrolyte layer.
[122]
[123]
In addition, in one embodiment of the present invention, the suppression layer may be patterned by a method of self-assembly of a polymer copolymer. Any method of manufacturing the suppression layer by self-assembly may be applied as long as it has a structure in which micelles are formed to be regularly or irregularly aligned in the suppression layer. For example, a suitable polymer copolymer capable of self-assembly is added to a solvent to prepare a polymer solution, and an inhibitory substance is added to the polymer solution to prepare a mixture for forming an inhibitory substance. The polymer solution and mixture may be subjected to a stirring process to uniformly disperse the added components in the solvent. In particular, by stirring the mixture, chemical bonding between the inhibitory substance and the polymer copolymer may be promoted. Next, the prepared mixture is applied to the surface of the prepared solid electrolyte layer and dried to induce self-assembly. For the application, for example, a spin coating method may be used. At this time, the coating speed may be controlled in the range of about 1,000 rpm to 5,000 rpm. On the other hand, in the present invention, the solvent may contain at least one selected from toluene, tetrahydrofuran, ethylene, acetone, chloroform, and dimethylformamide (DMF), for example, the side of the arrangement of micelles having a hexagonal dense structure In the solvent may contain toluene.
[124]
[125]
(3) All solid battery
[126]
The present invention provides an all-solid-state battery including the solid electrolyte membrane. In one embodiment of the present invention, the all-solid-state battery includes a negative electrode, a positive electrode, and a solid electrolyte membrane interposed between the negative electrode and the positive electrode, wherein the solid electrolyte membrane has the above-described characteristics.
[127]
3 is a schematic diagram of an all-solid-state battery 200 according to an embodiment of the present invention. In the all-solid-state battery, a positive electrode active material layer 220 is formed on a surface of a positive electrode current collector 210, and a negative electrode 240 is stacked with a positive electrode through a solid electrolyte membrane 230. In the solid electrolyte membrane 230, a first solid electrolyte layer 233, a suppression layer 232, and a second solid electrolyte layer 231 are sequentially stacked. In the negative electrode, lithium dendrites 241 may grow in a vertical direction, but growth may be suppressed by the suppression layer 232.
[128]
Meanwhile, in an embodiment of the present invention, in the all-solid-state battery, the first solid electrolyte layer of the electrolyte membrane contains a suppression material having a lower concentration than the suppression layer, and the first solid electrolyte layer is disposed to face the negative electrode. Can be. In an all-solid-state battery having such a structure, the first solid electrolyte layer has a higher concentration of the inhibitor than the second solid electrolyte layer, or the thickness of the first solid electrolyte layer is formed thicker than the thickness of the second solid electrolyte layer. It can have features of both.
[129]
[130]
In addition, in one embodiment of the present invention, an element such as a separate protective layer may be further added to the surface of the solid electrolyte membrane facing the negative electrode. In particular, a passivation film using an inorganic solid electrolyte, an inorganic material such as LiF or Li 2 O, or an organic material such as PEO may be disposed for the purpose of suppressing the reaction caused by direct contact with the Li metal .
[131]
[132]
In the present invention, the negative electrode may include a current collector and a negative electrode active material layer formed on the surface of the current collector, and the negative electrode active material layer includes at least one element belonging to an alkali metal, an alkaline earth metal, a group 3B, and a transition metal. can do. In a specific embodiment of the present invention, the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) or francium (Fr) as non-limiting examples of the alkali metal At least one or more metals selected from are exemplified, and preferably lithium is included. In a specific embodiment of the present invention, the negative electrode may be laminated by bonding a negative electrode current collector and a lithium metal thin film having a predetermined thickness by compression bonding.
[133]
[134]
In the present invention, the positive electrode includes a current collector and a positive electrode active material layer formed on at least one side of the current collector, and the upper electrode active material layer includes a positive electrode active material, a solid electrolyte, and a conductive material. In addition, in a specific embodiment of the present invention, the positive active material layer may further include a binder material. The addition of the binder material may increase the bonding strength between the positive electrode active material layer and the current collector and/or the solid electrolyte membrane, and independently or in addition to this, it is helpful to improve the bonding strength between constituents included in the positive electrode active material.
[135]
[136]
The positive electrode active material may be used without limitation as long as it can be used as a positive electrode active material for a lithium ion secondary battery. For example, the positive electrode active material may include a layered compound such as lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as the formula Li 1 + x Mn 2 - x O 4 (wherein x is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , and LiMnO 2 ; Lithium copper oxide (Li 2 CuO 2 );LiV 3 O 8 ,LiFe 3 O 4 ,V 2Vanadium oxides such as O 5 and Cu 2 V 2 O 7 ; Formula LiNi 1 - x M x O 2 (here, M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, including one or more of the above elements, x = 0.01 ~ 0.3 is represented by) Lithium nickel oxide, for example LiN 0.8 C 0.1 M 0.1 O 2 ; Chemical formula LiMn 2 - x M x O 2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) Or Li 2 Mn 3 MO A lithium manganese composite oxide represented by 8 (here, M = Fe, Co, Ni, Cu, or Zn); A lithium manganese composite oxide having a spinel structure represented by LiNi x Mn 2 - x O 4 ; LiMn 2 O 4 in which part of Li in the formula is substituted with alkaline earth metal ions ; disulfide compounds; Fe 2 (MoO 4 ) 3 and the like. However, it is not limited only to these.
[137]
[138]
The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; Carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fibers or metal fibers such as VGCF (Vapor grown carbon fiber); Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; It may include one or a mixture of two or more selected from conductive materials such as polyphenylene derivatives.
[139]
[140]
The binder material is not particularly limited as long as it is a component that aids in bonding of an active material and a conductive material and bonding to a current collector. Roxypropylcellulose, recycled cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various aerials Coalescence, etc. are mentioned. The binder resin may be included in a range of 1 to 30% by weight, or 1 to 10% by weight, based on 100% by weight of the electrode layer.
[141]
[142]
In one embodiment of the present invention, the negative electrode and/or the positive electrode may further include various additives for the purpose of supplementing or improving physicochemical properties. The additive is not particularly limited, but may include one or more additives such as an oxidation-stabilizing additive, a reduction-stabilizing additive, a flame retardant, a heat stabilizer, and an antifogging agent.
[143]
[144]
In addition, the current collector is generally made to have a thickness of 3 μm to 500 μm. Such a current collector is not particularly limited as long as it has high conductivity without causing chemical changes to the battery, for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel. Surface-treated carbon, nickel, titanium, silver, etc. may be used on the surface. Among them, it can be appropriately selected and used according to the polarity of the anode or the cathode.
[145]
[146]
In addition, the present invention provides a battery module including the secondary battery as a unit cell, a battery pack including the battery module, and a device including the battery pack as a power source.
[147]
[148]
In this case, a specific example of the device may include a power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EV), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf cart; Power storage systems, etc., but are not limited thereto.
[149]
[150]
(4) Method for producing a solid electrolyte membrane
[151]
Next, a method of manufacturing a solid electrolyte membrane having the above-described characteristics will be described. The manufacturing method described below is one of various methods that can be employed in manufacturing the solid electrolyte membrane according to the present invention, but is not limited thereto. First, a first solid electrolyte layer is prepared. The electrolyte layer may follow the method of manufacturing the solid electrolyte layer according to an embodiment of the present invention, and is not limited to a specific method. For example, when the electrolyte layer is a polymer electrolyte, a solid electrolyte layer may be prepared in the following manner. A polymer solution is prepared by dissolving a polymer resin in a suitable solvent such as acetonitrile, and lithium salt is added thereto to prepare a slurry for forming an electrolyte layer. The slurry may be heated to an appropriate temperature for dissolution of the polymer resin and lithium salt, and may be stirred for several to several tens of hours. In addition, the polymer solution may further include an initiator and a curing agent. The initiator and the curing agent may be added to the polymer solution together, or an additive solution including an initiator and a curing agent may be separately prepared and added to the slurry. In a specific embodiment of the present invention, the initiator may be included in the range of about 10 parts by weight to 20 parts by weight relative to the polymer resin used, and the curing agent may be included in the range of about 0.2 parts by weight to 3 parts by weight compared to the polymer resin used. I can. Then, the prepared slurry is applied to a release film and dried. In this way, a first solid electrolyte layer can be obtained. The release film may be removed in a final step after removing the release film and using the first solid electrolyte layer or forming a solid electrolyte membrane having all the elements.
[152]
[153]
Next, a suppression layer is formed on the surface of the first solid electrolyte layer. The suppression layer may be prepared in the form of a metal salt solution. For example, a hydrated metal salt may be prepared by dissolving it in ethanol or the like, and then coated on the surface of the solid electrolyte layer, dried, and coated on the surface of the solid electrolyte layer to prepare an integrated state. The application may be performed according to a conventional application method such as spin coating or dip coating, and is not limited to a specific method.
[154]
Thereafter, a second solid electrolyte layer is formed on the surface of the suppression layer. The second solid electrolyte layer is prepared in an integrated form with the suppression layer by preparing a slurry for forming a second solid electrolyte layer, like the first solid electrolyte layer, and then applying it to the surface of the suppression layer and drying it. Like formation, after coating on the surface of a separate release film, the release film may be removed and bonded to the surface of the suppression layer by a method of calendering or lamination.
[155]
In the present invention, the solvent used in each step is not limited to a specific one, and an appropriate one may be selected and used in consideration of the materials used. For example, organic solvents such as NMP (N-methyl pyrrolidone), DMF (dimethyl formamide), tetrahydrofuran, dimethoxyethane, nitromethane, acetone, pyridine, ethanol, acetonitrile, dimethyl acetamide, or water, etc. There are, and these solvents may be used alone or in combination of two or more.
[156]
Meanwhile, in a specific embodiment of the present invention, a suppression layer is further formed on the surface of the second solid electrolyte layer, and a third solid electrolyte layer is disposed on the surface of the suppression layer, so that at least two suppression layers are included. It is possible to provide a solid electrolyte membrane in the form of.
[157]
[158]
In the above manufacturing method, it has been described that each solid electrolyte layer includes a polymer solid electrolyte, but the present invention is not limited thereto, and each solid electrolyte layer may contain an inorganic solid electrolyte by replacing or with the polymer solid electrolyte as an electrolyte material. I can.
[159]
[160]
Hereinafter, the present invention will be described in more detail through examples, but the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.
[161]
[162]
[Example]
[163]
1. Preparation of solid electrolyte membrane
[164]
Example 1
[165]
(1) Preparation of the first solid electrolyte layer
[166]
A 4 wt% polymer solution was prepared by dissolving polyethylene oxide (PEO, Mw=4,000,000 g/mol) in acetonitrile (AN) solvent. At this time, LiTFSI was put together as a lithium salt so that [EO]/[Li+]=18/1 (molar ratio). The polymer solution was stirred overnight at 70° C. so that PEO and lithium salt were sufficiently dissolved. Next, an additive solution including an initiator and a curing agent was prepared. PEGDA (Mw=575) is used as the curing agent, and benzoyl peroxide (BPO) is used as the initiator. And acetonitrile was used as a solvent. The additive solution was stirred for about 1 hour so that the added components were well mixed. Thereafter, the additive solution was added to the polymer solution, and the two solutions were sufficiently mixed. The mixed solution was applied and coated on a release film using a doctor blade. The coating gap was 800 μm, and the coating speed was 20 mm/min. The release film coated with the solution was moved to a glass plate to maintain the level well, dried overnight at room temperature, and vacuum dried at 100° C. for 12 hours. In this way, a first solid electrolyte layer was obtained. The thickness of the obtained first solid electrolyte layer was about 50 µm.
[167]
[168]
(2) Preparation of suppression layer
[169]
HAuCl 4 · 3H 2 O was dissolved in ethanol at a concentration of 2 wt% to prepare a metal salt solution. 20 µl of the metal salt solution was coated on the first solid electrolyte layer obtained in the previous step by spin coating at a speed of 2,000 rpm.
[170]
[171]
(3) Preparation of the second solid electrolyte layer
[172]
A second solid electrolyte layer was prepared in the same manner as in the preparation of the first solid electrolyte layer.
[173]
[174]
(4) Preparation of multi-layered solid electrolyte membrane
[175]
The first solid electrolyte film and the second solid electrolyte film coated with the suppression layer were stacked and stacked, and the interval between the rolls was adjusted to 100 μm, and calendering was performed at 60°C. At this time, the suppression layer was disposed between the first and second solid electrolyte films. In this way, a solid electrolyte membrane in which a first solid electrolyte membrane, a suppression layer, and a second solid electrolyte membrane were sequentially stacked was obtained. The thickness of the obtained solid electrolyte membrane was about 100 μm. It was found that the suppression layer of the solid electrolyte membrane was formed very thin enough that it did not affect the total thickness of the solid electrolyte membrane.
[176]
[177]
Example 2
[178]
A solid electrolyte membrane was prepared in the same manner as in Example 1, except that the concentration of HAuCl 4 ·3H 2 O was set to 5 wt% when preparing the solid electrolyte layer .
[179]
[180]
Example 3
[181]
A solid electrolyte membrane having a structure stacked in the order of a first solid electrolyte layer, a suppression layer, a second solid electrolyte layer, a suppression layer, and a third solid electrolyte layer was prepared. The solid electrolyte membrane of Example 3 had a structure in which the suppression layer and the third solid electrolyte layer were further added to the electrolyte layer of Example 1, and only the stacked structure was different, and the method of manufacturing each layer was the same as that of Example 1.
[182]
[183]
Example 4
[184]
A solid electrolyte membrane was prepared in the same manner as in Example 1, except that H 2 PtCl 6 ·H 2 O was used as a material for the suppression layer when the solid electrolyte membrane was prepared.
[185]
[186]
Example 5
[187]
(1) Preparation of the first solid electrolyte layer
[188]
A 4 wt% polymer solution was prepared by dissolving polyethylene oxide (PEO, Mw=4,000,000 g/mol) in a solvent acetonitrile (AN). At this time, LiTFSI was put together as a lithium salt so that [EO]/[Li+]=18/1 (molar ratio). The polymer solution was stirred overnight at 70° C. so that PEO and lithium salt were sufficiently dissolved. Next, an additive solution including an initiator and a curing agent was prepared. PEGDA (Mw=575) is used as the curing agent, and benzoyl peroxide (BPO) is used as the initiator. And acetonitrile was used as a solvent. The additive solution was stirred for about 1 hour so that the added components were well mixed. Thereafter, the additive solution was added to the polymer solution, and the two solutions were sufficiently mixed. The mixed solution was applied and coated on a release film using a doctor blade. The coating gap was 800 μm, and the coating speed was 20 mm/min. The release film coated with the solution was moved to a glass plate to maintain the level well, dried overnight at room temperature, and vacuum dried at 100° C. for 12 hours. In this way, a first solid electrolyte layer was obtained. The thickness of the obtained first solid electrolyte layer was about 50 µm.
[189]
[190]
(2) Preparation of suppression layer
[191]
Polystyrene-block-poly4vinyl pyridine (S4VP, PS Mn 41.5kg/mol, P4VP Mn 17.5kg/mol) was stirred in toluene at a concentration of 0.5wt% at room temperature for one day. In this solution, HAuCl 4 · 3H 2 O was added at a concentration of 2 wt% compared to P4VP and stirred for 6 hours to allow Au ions to bind in the S4VP micelles. The solution was spin-coated on the obtained first solid electrolyte layer at a speed of 3,000 rpm to pattern S4VP micelles of a single layer through self-assembly. 5 shows an AFM image of the obtained inhibitory layer. The bright part is the micelle part, and the dark part shows the first solid electrolyte layer part. At this time, the size of the micelles was 40 nm, and the interval between micelles was about 70 nm.
[192]
[193]
(3) Preparation of the second solid electrolyte layer
[194]
A second solid electrolyte layer was prepared in the same manner as in the preparation of the first solid electrolyte layer.
[195]
[196]
(4) Preparation of multi-layered solid electrolyte membrane
[197]
The first solid electrolyte film coated with the suppression layer and the second solid electrolyte film were stacked and stacked, and the interval between the rolls was adjusted to 100 μm, and calendering was performed at 60°C. At this time, the suppression layer was disposed between the first and second solid electrolyte films. In this way, a solid electrolyte membrane in which a first solid electrolyte membrane, a suppression layer, and a second solid electrolyte membrane were sequentially stacked was obtained. The thickness of the obtained solid electrolyte membrane was about 100 μm. It was found that the suppression layer of the solid electrolyte membrane was formed very thin enough that it did not affect the total thickness of the solid electrolyte membrane.
[198]
[199]
Example 6
[200]
When preparing a solid electrolyte membrane, a solid electrolyte membrane was prepared in the same manner as in Example 5, except that the concentration of HAuCl 4 in the suppression layer was 5 wt% compared to S4VP.
[201]
[202]
Example 7
[203]
A solid electrolyte membrane was prepared in the same manner as in Example 5, except that polystyrene-block-poly2vynil pyridine (S2VP, PS Mn 133 kg/mol, P2VP Mn 132 kg/mol) was used as the block copolymer of the suppression layer when preparing the solid electrolyte membrane. .
[204]
[205]
Comparative Example 1
[206]
A solid electrolyte membrane was prepared in the same manner as in Example 1, except that the suppression layer was not inserted during the manufacture of the solid electrolyte membrane.
[207]
[208]
Comparative Example 2
[209]
When preparing the solid electrolyte layer, the procedure was performed in the same manner as in Comparative Example 1, except that a total of three solid electrolyte layers were stacked without an inhibitory layer.
[210]
[211]
2. Manufacture of battery
[212]
For the positive electrode slurry produced electrode active material is NCM811 (LiNi 0 . 8 Co 0 . 1 Mn 0 . 1 O 2 ), conductive material VGCF (Vapor grown carbon fiber) and the high-molecular solid solid electrolyte (PEO + LiTFSI, 18: 1 mol Ratio) was mixed at a weight ratio of 80:3:17, added to acetonitrile, and stirred to prepare an electrode slurry. An aluminum current collector having a thickness of 20 μm was prepared. The slurry was applied to the current collector using a doctor blade, and the resultant was vacuum-dried at 120° C. for 4 hours. The rolling process was carried out using a roll press to obtain an electrode having an electrode loading of 2 mAh/cm 2, an electrode layer thickness of 48 μm, and a porosity of 22%. Next, the electrode prepared above was prepared by punching into a circular shape of 1.4875 cm 2 . 1.7671 cm 2The lithium metal thin film cut into a circle of was prepared as a counter electrode. Between the two electrodes, the solid electrolyte membranes obtained in Examples 1 to 7, Comparative Examples 1 to 2 were placed, respectively, to prepare a coin-type half-cell.
[213]
[214]
3. Evaluation experiment
[215]
(1) Evaluation of the ion conductivity of the solid electrolyte layer
[216]
The solid electrolyte membranes prepared in Examples 1 to 7 and Comparative Examples 1 to 2 were cut into a circle of 1.7671 cm 2 . It was placed between two sheets of stainless steel (SUS) to fabricate a coin cell. Electrochemical impedance was measured under conditions of amplitude 10mV and scan range 500Khz to 20MHz at 60°C using an analysis device (VMP3, Bio logic science instrument), and ionic conductivity was calculated based on this.
[217]
[218]
(2) Evaluation of initial discharge capacity and life characteristics
[219]
The batteries prepared in Examples 1 to 7 and Comparative Examples 1 to 2 were charged and discharged at 0.05C at 60°C to evaluate the initial discharge capacity and discharge.
[220]
Charging condition: CC(constant current)/CV(constant voltage), (4.15V, 0.005C current cut-off)
[221]
Discharge condition: CC (constant current) condition 3V, (0.05C)
[222]
On the other hand, the time point of occurrence of the short circuit was determined as the time point of abnormal behavior (unstable voltage change) of the voltage during charging during life evaluation by charging and discharging at 0.1C.
[223]
[224]
[Table 1]
Ion conductivity (S/cm, 60℃) Discharge capacity (mAh/g, 4.15V) Short circuit occurrence time (cycle)
Example 1 1x10 -4 159 18
Example 2 9x10 -5 155 20
Example 3 9x10 -5 142 23
Example 4 1x10 -4 156 16
Example 5 8x10-5 151 17
Example 6 8x10-5 150 20
Example 7 8x10-5 142 14
Comparative Example 1 1x10 -4 156 5
Comparative Example 2 9x10 -5 145 8
[225]
[226]
As can be seen in Table 1, the batteries including the solid electrolyte membranes of Examples 1 to 7 of the present invention were found to have higher ionic conductivity and discharge capacity than the batteries of Comparative Example, and the time of occurrence of a short circuit was also delayed. That is, it was found that lithium dendrites were converted back to lithium ions through a chemical reaction with metal ions, which are inhibitors, to improve lifespan characteristics. At this time, the amount of metal ions or the uniformity of the coating layer are important. In the case of Examples 5 to 7 of the present invention, metal ions arranged in nanoscale through self-assembly of the block copolymer exhibited more effective lifespan characteristics improvement. 5 is an AFM picture of the surface of the suppression layer prepared in Example 5, and it was confirmed that micelles containing metal ions formed a certain pattern on the first solid electrolyte layer.
[227]
[228]
[Explanation of code]
[229]
10 all-solid-state battery, 11 current collector, 12 positive electrode, 13 solid electrolyte membrane, 14 negative electrode (lithium metal), 14a dendrite
[230]
130 solid electrolyte membrane, 131 second solid electrolyte layer, 132 suppression layer, 133 first solid electrolyte layer
[231]
200 all-solid-state battery, 210 current collector, 220 positive electrode, 231 second solid electrolyte layer, 232 suppression layer, 233 first solid electrolyte layer, 240 negative electrode (lithium metal), 241 dendrite
[232]
330 solid electrolyte membrane, 331 solid electrolyte layer, 332 suppression layer
[233]
430 solid electrolyte membrane, 431 second solid electrolyte layer, 433 first solid electrolyte layer, 432 suppression layer, 432a micelle
Claims
[Claim 1]
As for a solid electrolyte membrane for an all-solid battery, the solid electrolyte membrane has an ionic conductivity of 1x10 -7 S/cm or more, and the solid electrolyte membrane includes at least one suppression layer comprising a dendrite growth suppression material (a), the The dendrite growth inhibiting material (a) is derived from any one of (a1) a metal(s) having a lower ionization tendency than lithium and (a2) an alloy(s) of two or more of the above metals, and salts thereof and The solid electrolyte membrane, which is contained in the suppression layer in the form of at least one of ions of.
[Claim 2]
The solid electrolyte membrane according to claim 1, wherein the suppression layer is patterned by including a plurality of pattern units including a suppression material, and the pattern units are regularly or irregularly distributed in the suppression layer.
[Claim 3]
The micropattern of claim 2, wherein the suppression layer comprises a dendrite growth suppression material (a) and a polymer copolymer in which the suppression material is chemically bonded, and is derived from self-assembly of the polymer copolymer. And the polymeric copolymer comprises a functional group capable of chemical bonding with the inhibitory material, and the inhibitory material is bonded to the polymeric copolymer through the functional group.
[Claim 4]
The solid electrolyte membrane according to claim 3, wherein the suppression layer has a shape in which micelles are aligned according to a hexagonal dense structure by self-assembly of the polymer copolymer.
[Claim 5]
The solid electrolyte membrane according to claim 3, wherein the functional group is at least one of ether and amine.
[Claim 6]
The method of claim 3, wherein the polymer copolymer is polystyrene-blockpooly(2-vinylpyridine) copolymer, polystyrene-block-poly(4-vinylpyridine) copolymer, poly(1,4-isoprene)-blockpolystyrene-block-poly(2- A solid electrolyte membrane containing at least one selected from vinylpyridine) copolymer and polystyrene-block-poly(ethylene oxide) copolymer
[Claim 7]
The method of claim 1 or 2, wherein the metal is K, Sr, Ca, Na, Mg, Be, Al, Mn, Zn, Cr(+3), Fe, Cd, Co, Ni, Sn, Pb, Cu , Hg, Ag, Pd, Ir, Pt(+2), Au and Pt(+4) which contains one or more selected from the group consisting of, a solid electrolyte membrane.
[Claim 8]
The solid electrolyte membrane according to claim 1 or 2, wherein the inhibitory material comprises at least one selected from the group consisting of Au and Pt.
[Claim 9]
The method of claim 1 or 2, wherein the metal salt is chloride, iodide, cyanide, boride, sulfide, hydroxide, phosphite. ) And one or more of chloride hydrate, a solid electrolyte membrane.
[Claim 10]
The solid electrolyte membrane according to claim 1 or 2, wherein the solid electrolyte membrane includes at least two solid electrolyte layers and at least one suppression layer, and the suppression layer is disposed between the solid electrolyte layers.
[Claim 11]
The solid electrolyte membrane according to claim 10, wherein the solid electrolyte membrane includes a first solid electrolyte layer, a suppression layer, and a second solid electrolyte layer sequentially stacked.
[Claim 12]
The method of claim 10, wherein at least one of the two or more solid electrolyte layers contains an inhibitory material, and the content (wt%) of the inhibitory substance in each solid electrolyte layer is greater than the content (wt%) of the inhibitory substance included in the suppression layer. A solid electrolyte membrane that is low.
[Claim 13]
The solid according to claim 1 or 2, wherein the solid electrolyte membrane comprises an ion conductive solid electrolyte material, and the ion conductive solid electrolyte material comprises a polymer solid electrolyte, an inorganic solid electrolyte, or a mixture of both. Electrolyte membrane.
[Claim 14]
The solid electrolyte membrane according to claim 13, wherein the polymer solid electrolyte comprises a polymer resin and a solvated lithium salt.
[Claim 15]
An all-solid-state battery comprising a negative electrode, a positive electrode, and a solid electrolyte membrane interposed between the negative electrode and the positive electrode, wherein the negative electrode contains lithium metal, and the solid electrolyte membrane is according to claim 1 or 2, electrochemical device.
[Claim 16]
The method of claim 15, wherein the solid electrolyte membrane is a first solid electrolyte layer, a suppression layer, and a second solid electrolyte layer are sequentially stacked, the first solid electrolyte layer comprises a suppression material (a), the suppression material An electrochemical device that is derived from any one of (a1) metal(s) having a lower ionization tendency than lithium and (a2) alloy(s) of two or more of the metals.