Solid electrolytes and electrodes for solid-state batteries, and methods for manufacturing the same.

Abstract

The technologies of this disclosure generally relate to the field of power storage devices, and more specifically to solid electrolytes, electrodes, solid batteries, and methods for manufacturing them. The solid electrolytes of this disclosure include a porous composite network obtained by the reaction of an alkoxide compound with a polymer precursor compound; wherein the alkoxide compound is selected from the group consisting of silica alkoxide, alumina alkoxide, zirconium alkoxide, and mixtures thereof; wherein the polymer precursor compound includes two terminal functional groups, the at least one of which is selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof; wherein the polymer precursor compound includes polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF); wherein the porous composite network is functionalized with an electrolyte containing an ion-conducting compound in which a metal salt is dissolved; and wherein the porous composite network includes clay mineral particles, preferably clay mineral nanoparticles.

Description

[Technical Field]

[0001] Field of Invention The technologies disclosed herein generally relate to the field of power storage devices, and more specifically to solid electrolytes, electrodes, solid batteries, and methods for manufacturing them. [Background technology]

[0002] background Electrochemical energy storage devices are widely used in transportation applications ranging from automotive to aviation, and from marine to space. However, conventional liquid electrolytes are flammable and volatile, posing a fire hazard in case of leakage. Therefore, the development of solid-state batteries containing solid electrolytes is becoming increasingly important, especially given the growing demands for higher energy and safety. To pursue solid electrolytes with desirable properties, several types of materials, including organic and inorganic materials such as ceramics, polymers, and gel electrolytes, have been investigated.

[0003] Polymer-based sol-gel chemistry is a crucial technique for incorporating highly crosslinked inorganic networks into organic polymer matrices. The advantages of sol-gel reactions in polymer technology include easy production, low-cost chemicals, their versatility, preparation under mild conditions (i.e., low temperature and air), the possibility of coating substrates of any size and over-large area, and inexpensive and well-known application techniques. In this method, hydrolysis and polycondensation reactions occur of alkoxysilane monomers containing polymerizable organic moieties covalently bonded to silicon, followed by polymerization reactions of the organic moieties, forming connectivity between the organic phase and the inorganic network.

[0004] Efforts are being made to utilize silica electrolytes in lithium batteries. For example, European Patent No. EP3706226 describes the use of a nanocomposite made of mesoporous silica having an ionic liquid electrolyte filler as a solid electrolyte for lithium batteries. However, because pure inorganic glass networks lack flexibility, the brittle silica network cannot withstand the stresses generated during the coating process, which can lead to cracking of the coating film. For this reason, there are limitations to using mesoporous silica as an electrolyte in battery systems.

[0005] Nevertheless, the use of various additives has been proposed to improve the ionic conductance of silica electrolytes. For example, European Patent No. EP3780163 describes the formation of a polymer polarization layer adsorbed on the inner surface of the pores of a porous silica matrix. Although improvements in ionic conductance have been reported, the mechanical brittleness of the silica matrix cannot be addressed even with the inclusion of such additives.

[0006] In fact, stress cracking significantly limits the range of applications for which sol-gel processes can be used, making it impossible to produce large monolithic glasses and thick self-standing films. Thus, obtaining crack-free films of several micrometers (e.g., in the range of >20 μm and <150 μm on the top of an electrode) without adding extra film to provide mechanical strength is extremely difficult based on a pure silica matrix.

[0007] US 2013 / 0209893 A1 relates to nanoparticle organic hybrid materials (NOHMs), methods for producing NOHMs, and compositions containing NOHMs. Each NOHM comprises a silica core and an organic polymer corona or arm attached to an inorganic nanoparticle core.

[0008] KR 20150061538 A relates to a support prepared from a resin composition containing a polymer formed by branching a block copolymer comprising a polypropylene oxide block and a polyethylene oxide block; an electrolyte membrane comprising the support and an ion-conducting electrolyte supported on the support; a method for manufacturing the electrolyte membrane; and a battery and an ultra-high-capacity capacitor comprising the electrolyte membrane.

[0009] Velez John Fredy et al. developed silica-polyethylene glycol PEG containing bis(trifluoromethane)sulfonimide lithium salt (LiTFSI) or lithium trifluoromethanesulfonate (LiOTf) synthesized by a sol-gel process. (200,400) This relates to organic-inorganic hybrid solid electrolytes based on the following.

[0010] WO 2018 / 071322 A1 relates to a composite material comprising a ceramic portion, a metal oxide portion, and a coupling agent portion, wherein the coupling agent is covalently bonded to the metal oxide; and to a method for manufacturing the composite material.

[0011] None of these publications adequately address the aforementioned limitations of current battery technology. Therefore, these limitations need to be corrected by providing solid electrolytes with improved mechanical properties, without reducing the ion conductance of the solid electrolyte, and advantageously with further improvements; this is necessary for the development of commercially relevant solid batteries. [Overview of the project]

[0012] Summary of the Invention The technology of this disclosure relates generally to the field of power storage devices, and more specifically to solid electrolytes comprising a porous network doped with an ion-conductive compound. The porous network may comprise silica and a functionalized polymer, thereby forming multiple chains that are covalently grafted within the silica network to form a porous composite network.

[0013] The composite porous networks disclosed herein can be produced, for example, by mixing one or more alkoxide compounds, preferably silica precursors, with one or more functionalized polymer precursors using a sol-gel process. In-situ formation of the composite porous network can improve the flexibility and integrity of the solid electrolyte. Specifically, the composite network can reduce stress cracking during the curing process and enable coating of larger size and / or extremely large surface area substrates.

[0014] The possibility of using polymer additives was considered, for example, in European Patent No. EP3780163, to form a surface layer, but they were unable to improve the mechanical properties of the solid electrolyte. More specifically, the polymer chains of the additives adsorb to the surface of porous silica and do not covalently adhere to the silica network, so polymer aggregates are formed and the polymer is unevenly dispersed in the silica matrix. As a result, the polymer cannot improve the flexibility of the electrolyte and cannot prevent the occurrence of cracks in the coating film.

[0015] This is in contrast to the composite porous network disclosed herein, in which polymer chains form an integral part of the network network. Therefore, as will be discussed later, this can contribute to improvements in the mechanical properties (e.g., improved resilience and flexibility), ionic properties (e.g., improved ionic conductivity through optimized lithium ion transport pathways), and / or thermal properties (e.g., reduced thermal degradation) of the solid electrolyte. Indeed, the presence of integrated polymer chains can lead to strong dissociation of lithium salts, thereby improving the ionic conductivity of the solid electrolyte, which is particularly suitable for the manufacture of high-energy solid-state batteries. Silane-terminated groups provide further mechanical compliance and structural integrity under compression processes, strengthening the electrolyte backbone.

[0016] Also, in certain embodiments, the solid electrolyte may include clay mineral particles that can improve the lithium ion conductivity and lithium ion transference number for the electrolyte. The provision of clay mineral nanoparticles such as halloysite nanotubes (HNTs) provides additional advantages for obtaining a homogenous dispersion in, for example, a (coating / coating) layer formed on an electrode active material. Without wishing to be bound by theory, it has been found that the opposite surface charges on halloysite separate the lithium salt into lithium cations, which are adsorbed onto the negatively charged silica surface outside the HNTs, and the anions of the lithium salt are expected to be adsorbed onto the positively charged aluminol surface inside the HNTs. Thus, by adding HNTs, the electrochemical and thermal stability can be further improved. Also, HNTs can improve the mechanical strength of the solid electrolyte.

[0017] The following presents an overview of various aspects of the technology of the present disclosure, followed by a more detailed description of specific embodiments. This overview is intended to assist the reader in more quickly understanding the technical concepts, but is not intended to identify the most important or essential features, nor is it intended to limit the scope of the present disclosure, which is limited only by the claims.

[0018] Aspects of the present disclosure relate to a solid electrolyte for an electrochemical energy storage device comprising a porous composite network comprising silica and silane-terminated polymers; whereby said silica and polymers are covalently grafted within said network; wherein said network is functionalized with an electrolyte comprising an ion-conductive compound in which a metal salt is dissolved.

[0019] A further aspect of the present disclosure relates to a solid electrolyte for an electrochemical energy storage device comprising a porous composite network obtained by the reaction of an alkoxide compound and a polymer precursor compound; Among these, the alkoxide compound is selected from the group consisting of silica alkoxide, alumina alkoxide, zirconium alkoxide, and mixtures thereof; Among these, the polymer precursor compound comprises at least one terminal functional group selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof; Among these, the polymer precursor compound includes polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF); Within this, the porous composite network is functionalized with an electrolyte containing an ion-conducting compound in which a metal salt is dissolved; and Within this porous composite network, clay mineral particles, preferably clay mineral nanoparticles, are included.

[0020] In some embodiments, the porous composite network includes natural clay mineral particles, preferably natural clay mineral nanoparticles.

[0021] In some embodiments, the polymer precursor compound comprises at least two terminal functional groups, the at least one of which is selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof.

[0022] In some embodiments, the clay mineral particles are elongated nanoparticles, preferably including nanowires, nanofibers, nanotubes, and / or nanorods.

[0023] In some embodiments, the clay mineral particles include nanostructures having a tubular shape with a negatively charged exterior and a positively charged interior.

[0024] In some embodiments, the clay mineral particles include nanostructures having a tubular shape with a hollow interior.

[0025] In some embodiments, the clay mineral particles are selected from the group consisting of palygorskite, attapulgite, kaolin, smectite, illite, chlorite, sepiolite, vermiculite, and mixtures thereof; preferably palygorskite, kaolin, and / or attapulgite.

[0026] In some embodiments, the silica alkoxide is selected from the group consisting of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), triethyl vinyl orthosilicate (VTEOS), or substitutions thereof, and / or combinations thereof.

[0027] In one embodiment, the alumina alkoxide is selected from the group consisting of aluminum triethoxide, aluminum trimethoxide, aluminum triisopropoxide, or substituted derivatives thereof, and / or combinations thereof.

[0028] In one embodiment, the zirconium alkoxide is selected from the group consisting of zirconium tetraethoxide, zirconium tetramethoxide, zirconium tetraisopropoxide, or substituted derivatives thereof, and / or combinations thereof.

[0029] In preferred embodiments, the porous composite network is an inorganic-organic hybrid network, and preferably comprises a copolymer of an alkoxide compound and a polymer precursor compound.

[0030] In some embodiments, the polymer comprises polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF).

[0031] In some embodiments, the polymer comprises a mono- and / or bi-terminal reactive functional group, preferably the polymer precursor compound comprising one and / or two reactive end functional groups.

[0032] In some embodiments, the polymer contains alkoxysilanes and / or alkoxyaluminums as terminal reactive functional groups.

[0033] In some embodiments, the solid electrolyte comprises halloysite nanotubes (HNTs); preferably aluminosilicate (Al2Si2O5(OH)4) nanoclay.

[0034] In some embodiments, the clay mineral particles include halloysite nanotubes (HNTs) containing aluminosilicate (Al2Si2O5(OH)4).

[0035] In some embodiments, the amount of clay mineral particles or nanoparticles is at least 0.1% by weight to at most 10% by weight, preferably at least 0.5% by weight to at most 10% by weight, and more preferably at least 1.0% by weight to at most 10% by weight, relative to the total weight of the solid electrolyte.

[0036] In some embodiments, the amount of HNT is at least 0.1% to at most 10% by weight, preferably at least 0.5% to at most 10% by weight, and more preferably at least 1.0% to at most 10% by weight, relative to the total weight of the solid electrolyte.

[0037] Another aspect of this disclosure relates to an electrode comprising a solid electrolyte and an electrode active material according to any of the above aspects.

[0038] In some embodiments, the solid electrolyte forms a coating layer on the electrode active material. Advantageously, the solid electrolyte forms a thin coating layer on the electrode active material.

[0039] In some embodiments, the coating layer has a thickness of less than about 200 μm (below), more preferably less than about 100 μm, and even more preferably less than about 60 μm, both after drying and before compression.

[0040] In some embodiments, the coating layer is a crack-free, uniform and / or homogeneous coating layer. Advantageously, clay mineral particles are uniformly and / or homogeneously dispersed in the coating layer.

[0041] Another aspect of this disclosure relates to an electrochemical energy storage device comprising a positive electrode, a negative electrode, and a solid electrolyte by any of the above aspects.

[0042] In some embodiments, the solid electrolyte forms an overfill on top of the positive and / or negative electrodes.

[0043] In some embodiments, the solid electrolyte forms an overfill only on top of the positive electrode.

[0044] Another aspect of this disclosure is: The process involves mixing a silica precursor, a silane-terminated polymer compound, an ion-conducting compound, a metal salt, and an organic solvent to form a liquid mixture; • A step of gelling a liquid mixture to form a gel mixture; and • A process of drying and / or aging the gel mixture to form a solid electrolyte. The present invention relates to a method for producing a solid electrolyte, comprising at least [a certain element].

[0045] Further aspects of this disclosure are: The process involves mixing an alkoxide compound, a polymer precursor compound containing PEG and / or PTHF, an ion-conducting compound, a metal salt, clay mineral particles, and a solvent to form a liquid mixture; • A step of gelling a liquid mixture to form a gel mixture; and • A process of drying and / or aging the gel mixture to form a solid electrolyte. The present invention relates to solid electrolytes, including, and preferably to methods for producing solid electrolytes as disclosed herein.

[0046] In some embodiments, the polymer compound comprises polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF).

[0047] In some embodiments, the mixing of a silica precursor and a silane-terminated polymer precursor involves covalently bonding the polymer compound to the silica precursor so that a porous composite network is formed, thereby covalently grafting the silica and silane-terminated polymer within the network.

[0048] In some embodiments, the polymer compound is given by the following formula:

[0049] [ka]

[0050] (In the formula, TG is a reactive terminal functional group, preferably alkoxysilane and / or alkoxyalumina, R is an alkyl group, and n is in the range of 6 to 1300, preferably 6 to 100, more preferably 6 to 9.) According to this, it contains a mono-terminal reactive functional group.

[0051] In some embodiments, the polymer precursor compound is given by the following formula:

[0052] [ka]

[0053] (In the formula, TG is a reactive terminal functional group selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof; R is an alkyl group; and n is in the range of 6 to 1300, preferably 6 to 100, more preferably 6 to 9.) Accordingly, it contains one reactive terminal functional group and one non-reactive terminal functional group.

[0054] In some embodiments, the polymer compound is given by the following formula:

[0055] [ka]

[0056] (In the formula, TG is a reactive terminal functional group, preferably alkoxysilane and / or alkoxyalumina, R is an alkyl group, and n is in the range of 6 to 13000, more preferably 6 to 1000, and even more preferably 6 to 150.) Accordingly, it contains a bi-terminal reactive functional group.

[0057] In some embodiments, the polymer precursor compound is given by the following formula:

[0058] [ka]

[0059] (wherein TG is a reactive terminal functional group selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof; R is an alkyl group; and n is in the range of 6 to 13000, more preferably 6 to 1000, and even more preferably 6 to 150.) Accordingly, it contains two reactive terminal functional groups.

[0060] In some embodiments, the polymer compound comprises a combination of two or more polymer compounds; in which at least one polymer comprises a reactive single-termined functional group, and at least one polymer comprises reactive double-termined functional groups.

[0061] In some embodiments, the methods disclosed herein include combinations of two or more polymer compounds; in which at least one polymer preferably comprises one reactive terminal functional group and one non-reactive terminal functional group according to any of the above embodiments, and at least one polymer preferably comprises two reactive terminal functional groups according to any of the above embodiments.

[0062] In some embodiments, the amount of the polymer compound is at least 3% by weight and at most 15% by weight relative to the total weight of the solid electrolyte.

[0063] Several embodiments In some embodiments, the silica precursor includes silicon alkoxide; preferably tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), triethyl vinyl orthosilicate (VTEOS), or substituted derivatives thereof, and / or combinations thereof.

[0064] In some embodiments, the liquid mixture contains halloysite nanotubes (HNTs), preferably from aluminosilicate (Al2Si2O5(OH)4) nanoclay.

[0065] In some embodiments, the amount of HNT is at least 0.5% by weight and at most 10% by weight relative to the total weight of the solid electrolyte. [Brief explanation of the drawing]

[0066] Description of the drawing The following description of the drawings relates to specific embodiments of the Disclosure and is illustrative in nature, and is not intended to limit the teaching or application of the Disclosure.

[0067] Throughout the drawings and their descriptions, the following abbreviations are used: silane-terminated polyethylene glycol (SPEG); halloysite nanotube (HNT); tetraethoxysilane (TEOS); 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI); lithium bis(trifluoromethane)sulfonimide (TFSI); lithium nickel manganese cobalt oxide (NMC) cathode; lithium iron phosphate (LFP); electrochemical impedance spectroscopy (EIS); thermogravimetric analysis (TGA); scanning electron microscope (SEM).

[0068] [Figure 1] Figure 1 shows a graphic representation of in situ formation of a composite network containing silica and silane-terminated PEG chains. [Figure 2] Figure 2 shows a graphical representation of in-situ formation of a composite network containing silica, silane-terminated PEG chains, and HNTs. [Figure 3] Figure 3 shows a dry electrolyte membrane prepared by drop casting of pure silica electrolyte. [Figure 4] Figure 4 shows a dry electrolyte membrane prepared by drop casting of a composite electrolyte containing 5% by weight of SPEG. [Figure 5] Figure 5 shows a dry electrolyte membrane prepared by drop casting of a composite electrolyte containing 10% by weight of SPEG. [Figure 6] Figure 6 shows a self-supporting membrane of a dry electrolyte prepared by drop casting of a composite electrolyte containing 5.0 wt% SPEG. [Figure 7] Figure 7 shows a self-supporting membrane of a dry electrolyte prepared by drop casting of a composite electrolyte containing 10 wt% SPEG and 0.5 wt% HNT. [Figure 8] Figure 8 shows a 200 μm thick dry electrolyte membrane after folding, prepared by drop casting of a composite electrolyte containing 7 wt% SPEG + 1 wt% HNT onto the top of a porous composite cathode. [Figure 9] Figure 9 shows an SEM image of a 14 μm thick dry electrolyte film prepared by blade coating with pure silica electrolyte. [Figure 10] Figure 10 shows an SEM image of a 78 μm thick dry electrolyte membrane prepared by blade coating with a composite electrolyte containing 3 wt% SPEG. [Figure 11] Figure 11 shows an SEM image of a 96 μm thick dry electrolyte membrane prepared by blade coating with a composite electrolyte containing 10 wt% SPEG and 3 wt% HNT. [Figure 12] Figure 12 shows the ionic conductivity (mS / cm) of electrolyte membranes prepared by drop casting of pure silica electrolyte, a composite electrolyte containing 5.0 wt% SPEG, a composite electrolyte containing 0.5 wt% HNT, a composite electrolyte containing 7.0 wt% SPEG and 1.0 wt% HNT, and a composite electrolyte containing 10.0 wt% SPEG and 0.8 wt% HNT. [Figure 13] Figure 13 shows the measured ionic conductivity (mS / cm) of electrolyte membranes prepared by drop casting of a pure silica electrolyte, a composite electrolyte containing 10.0 wt% SPEG, and a composite electrolyte containing 10.0 wt% SPEG and 0.8 wt% HNT. [Figure 14]Figure 14 shows the ionic conductivity (mS / cm) of electrolyte membranes prepared by drop casting of pure silica electrolyte and a composite electrolyte containing 3.0 wt% SPEG and 3.0 wt% HNT as a function of different compression pressures (thickness %). [Figure 15] Figure 15 shows the electrolyte membrane after 40% compression, prepared by drop casting of pure silica electrolyte. [Figure 16] Figure 16 shows the electrolyte membrane after 40% compression, prepared by drop casting of a composite electrolyte membrane containing 3 wt% SPEG and 3.0 wt% HNT. [Figure 17] Figure 17 shows the thermal degradation of electrolyte membranes prepared by drop casting of pure silica electrolyte, pure HNT, and a composite electrolyte containing 3.0 wt% HNT over a temperature range of 0–600°C. [Figure 18] Figure 18 shows the thermal degradation of electrolyte membranes prepared by drop casting of pure silica electrolyte, pure HNT, pure SPEG, a composite electrolyte containing 5.0 wt% SPEG, and a composite electrolyte containing 5.0 wt% SPEG and 0.5 wt% HNT, over a temperature range of 0 to 600°C. [Figure 19] Figure 19 shows the charge / discharge voltage curves of a full cell battery fabricated based on a stack of Li / 5.0 wt% SPEG and 1.0 wt% HNT composite electrolyte / LiFePO4 for the 1st, 2nd, and 100th cycles. [Figure 20] Figure 20 shows the long-term cycle performance of the battery shown in Figure 19 at room temperature. [Modes for carrying out the invention]

[0069] Detailed explanation The following detailed description explains the underlying technology of this disclosure by its different aspects. It will be readily apparent that the aspects of this disclosure generally described herein and shown in the drawings can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are expressly intended and constitute part of this disclosure. This description is intended to help the reader more easily understand the technical concepts, but is not intended to limit the scope of this disclosure, which is limited solely by the claims.

[0070] Throughout this specification, any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of this disclosure. Therefore, the occurrences of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification do not necessarily all refer to the same embodiment.

[0071] As used herein, the terms “comprising,” “comprises,” and “comprised of” are synonymous with “including,” “includes,” or “containing,” and are comprehensive or open, not excluding any additionally mentioned members, elements, or process steps of a method. When referring to any enumerated member, element, or process step, the terms “comprising,” “comprises,” and “comprised of” also include embodiments that “consist of” such enumerated member, element, or process step. The singular forms “a,” “an,” and “the” include both singular and plural referents unless the context explicitly indicates otherwise.

[0072] In this specification, "connected" or "coupled" refers to an object that reflects a functional relationship between the objects described; that is, the term indicates that the objects described must be connected in order to perform a specified function, which may include direct or indirect connections, either physical or non-physical, as appropriate to the context in which the term is used.

[0073] As used herein, the term “substantially” refers to the complete or near-complete range or degree of an action, characteristic, nature, state, structure, item, or result. For example, something “substantially” enclosed means that it is either completely enclosed or nearly completely enclosed. The exact degree of deviation from absolute completeness that is permissible may sometimes depend on the specific context. However, generally speaking, proximity to completion is such that the same overall result as if absolute and comprehensive completion were attained. The use of “substantially” is equally applicable when used in a negative connotation referring to the complete or near-complete absence of an action, characteristic, nature, state, structure, item, or result.

[0074] Where used herein, the term “about” is used to provide flexibility to the endpoint of a number or range by specifying, depending on the particular context, that a given value may be “a little above” or “a little below” the aforementioned value or endpoint. Unless otherwise noted, the use of the term “about” in reference to a particular number or range of numbers should be understood as providing support for the term or range of such numbers without the term “about.” For example, the reference to “about 30” should be interpreted as providing support not only for values ​​a little above and a little below 30, but also for the actual number 30.

[0075] References to numerical ranges by endpoint include not only the endpoint mentioned but also all numbers and fractions contained within each range. Furthermore, in the description and claims, terms such as first, second, third, etc., are used to distinguish similar elements and are not necessarily used to describe a sequential or chronological order unless explicitly stated. The terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that the embodiments of the disclosure described herein may operate in an order other than that described herein.

[0076] In this specification, we may refer to devices, structures, systems, or methods that provide “improved” performance (e.g., increased or decreased results, depending on the context). Unless otherwise specified, such “improvement” should be understood as a measure of the benefit obtained based on comparison with prior art devices, structures, systems, or methods. Furthermore, it should be understood that the degree of improved performance may differ among the disclosed embodiments, and that no equality or consistency in the quantity, degree, or realization of improved performance is assumed to be universally applicable.

[0077] The following outlines various aspects of the technology of this disclosure, followed by a more detailed description of specific embodiments. This outline is intended to help the reader more quickly understand the technical concepts, but it is not intended to identify its most important or essential features, nor is it intended to limit the scope of this disclosure, which is limited only by the claims. When describing specific embodiments, the accompanying drawings are referenced, but these drawings are provided solely to aid in understanding the embodiments described.

[0078] This description describes a technique for producing a solid electrolyte suitable for the manufacture of (solid) batteries. More specifically, a solid electrolyte comprising a porous network doped with an ion-conducting compound is disclosed. The porous network may comprise silica and a functionalized polymer, the polymer forming multiple chains that are covalently grafted into the silica network to form a porous composite network.

[0079] In one embodiment, the porous network may include aluminum and a functionalized polymer, the polymer forming a plurality of chains that are covalently grafted into the aluminum network to form a porous composite network.

[0080] In one embodiment, the porous network may include zirconium and a functionalized polymer, the polymer forming a plurality of chains that are covalently grafted within the zirconium network so as to form a porous composite network.

[0081] The terms “matrix” and “network” are used interchangeably herein and refer to a three-dimensional crosslinked polymer structure in which polymer chains are covalently bonded together. Preferably, the functionalized polymers are silane-terminated polyethers, e.g., polyethylene glycol (PEG) and polytetrahydrofuran (PTHF). As used herein, silane-terminated polymers refer to polymers terminating with a silyl group. The polymer may advantageously contain reactive 1-terminus and / or bi-terminus functional groups, e.g., alkoxysilane groups.

[0082] In some embodiments, the functionalized polymers are alkoxyaluminum-terminated polyethers, such as polyethylene glycol (PEG) and polytetrahydrofuran (PTHF). As used herein, alkoxyaluminum-terminated polymers refer to polymers terminating with an alkoxyaluminum group. The polymers may advantageously contain reactive functional groups at one and / or both ends, such as alkoxyaluminum groups.

[0083] In some embodiments, the functionalized polymers are alkoxyzirconium-terminated polyethers, such as polyethylene glycol (PEG) and polytetrahydrofuran (PTHF). As used herein, alkoxyzirconium-terminated polymers refer to polymers terminating with an alkoxyzirconium group. The polymers may advantageously contain reactive functional groups at one and / or both ends, such as alkoxyzirconium groups.

[0084] In aspects of the present disclosure, a solid electrolyte for an electrochemical energy storage device comprises a porous composite network obtained by the reaction of an alkoxide compound with a polymer precursor compound; wherein the alkoxide is selected from the group consisting of silica alkoxide, alumina alkoxide, zirconium alkoxide, and mixtures thereof; wherein the polymer precursor compound comprises two terminal functional groups selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof; wherein the polymer precursor compound comprises polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF); wherein the porous composite network is functionalized with an electrolyte comprising an ion-conducting compound in which a metal salt is dissolved; and preferably, wherein the porous composite network comprises clay mineral particles, preferably clay mineral nanoparticles.

[0085] Those skilled in the art will understand that the composition of the polymer precursor compound is adapted to match the alkoxide compound for initiating polymerization. Specifically, the polymer precursor compound may contain at least an alkoxysilane as a terminal functional group if the alkoxide compound contains a silica alkoxide, at least an alkoxyaluminum if the alkoxide compound contains an alumina alkoxide, and / or at least an alkoxyzirconium if the metal contains a zirconia alkoxide.

[0086] To form an in-situ porous silica network covalently grafted with functionalized polymer chains, the porous composite network disclosed herein can be produced, for example, by a sol-gel process described later, through the reaction of an alkoxide compound with a polymer precursor compound, preferably a silica precursor with a polymer precursor containing a reactive silane-terminated functional group.

[0087] As used herein, the term "in-situ" indicates that a porous network is an inorganic-organic hybrid network containing inorganic and organic segments within the backbone and / or side chains of a crosslinked polymer structure. Thus, functionalized polymer chains can be incorporated into (i.e., covalently bonded to) the polymer backbone and / or side chains. In-situ formation of composite porous networks can improve the flexibility of solid electrolytes. Specifically, the presence of functionalized polymer chains grafted within silica allows the composite network to reorganize and fill the solvent space upon solvent evaporation, forming a crack-free, uniform electrolyte film. This enables coating of substrates of any size and extremely large area.

[0088] In certain embodiments, the porous composite network is an inorganic-organic hybrid network, preferably comprising a copolymer of an alkoxide compound and a polymer precursor compound.

[0089] As used herein, the term "copolymer" refers to a polymer formed by the polymerization of at least two different monomers or macromers. Copolymers can be linear or non-linear (i.e., branched) depending on the number of reactive functional groups present in each monomer. Typically, monomers with two functional groups primarily produce linear copolymers, while monomers with more than two functional groups primarily produce branched copolymers. When the polymer chains of a branched copolymer covalently bond (across gel points), a three-dimensional crosslinking network is typically formed.

[0090] It should be understood that the monomers disclosed herein (i.e., alkoxide compounds and polymer precursor compounds) typically contain more than two reactive functionalities, enabling the formation of branched copolymer structures.

[0091] In some embodiments, the porous composite network may include branched copolymers, particularly graft copolymers, in which the main chain mainly consists of (inorganic) silica, and the side chains mainly consist of functionalized (organic) polymer chains.

[0092] The formed polymer chains are part of a functionalized compound that can be included in the electrolyte system as a second silica precursor (i.e., monomer). As a result, once the composite network is formed, the polymer chains are directly grafted into the porous silica, which can improve the flexibility of the material, help control its rheological properties, and reduce the hardness of the highly packed silica system, thus enabling the formation of a crack-free, uniform electrolyte membrane, as will be discussed later. Furthermore, the composite network acts as a reinforcing agent, providing the polymer with greater mechanical compliance and structural integrity under compression processes, thermal distortion temperatures, plateau modulus, and low thermal expansion coefficients, resulting from volume changes that occur during cycling (for example, when lithium is used as the anode).

[0093] In this way, a combination of functionalized polymer and inorganic composite network is obtained, which provides flexibility and reduces the brittleness inherent in pure inorganic glass. This combination helps prevent stress cracking during the curing process and allows coating of substrates with extremely large surface areas. In comparison, with silica particles as described in the above references, any additional polymer is grafted only onto the surface of the composite network, and therefore essentially forms a "coating" inside the pores of the composite network.

[0094] This has the advantage that the present invention enables the introduction of graft polymer structures to both the surface and bulk of porous composite networks, resulting in a more homogeneous distribution of inorganic segments (e.g., providing strength) and organic segments (e.g., providing flexibility and optimizing lithium ion transport pathways) across and within the porous structure.

[0095] Furthermore, the presence of functionalized polymer chains can lead to strong dissociation of the dissolved metal salt, and the strong interaction between the oxygen atoms of the polymer and the ions allows the ions to diffuse within the porous silica. As a result, the coordination between the oxygen atoms and lithium ions is further relaxed, thereby promoting ion transport through the complex network. This can improve the ionic conductivity of the solid electrolyte, making it suitable for the manufacture of high-energy solid-state batteries, as will be discussed later.

[0096] As used herein, the term “solid” refers to a system that is solid as a whole at room temperature. The inclusion of a partial liquid is not excluded. For example, a gel is considered a “solid.” Therefore, “solid electrolyte” as disclosed herein refers to an electrolyte that is solid at room temperature, suitable for the manufacture of solid-state batteries. Alternatively, or in combination, an electrolyte may be referred to as a “composite electrolyte,” more specifically a combination of composite networks and functionalized polymers, based on a combination of constituent materials.

[0097] In a preferred embodiment, the composite network includes porous silica. The porous silica can be, for example, mesoporous silica. The porous silica can have a porosity in the range of 25% to 90%. The porous silica can have a plurality of interconnected pores. The plurality of pores can also be referred to as continuous pores. Incidentally, the plurality of pores can include isolated pores. The porous composite network is functionalized with an electrolyte as described below, which may at least partially fill the interior of the plurality of pores or may completely fill the interior of the plurality of pores. The diameter of each pore of the porous silica is, for example, in the range of 2 nm to 100 nm.

[0098] As used herein, the term "alkoxide" may refer to a metal alkoxide (e.g., alumina alkoxide or zirconium alkoxide) and / or a metalloid alkoxide (e.g., silica alkoxide). As described herein, an alkoxide can be represented by the following formula (I) or (II):

[0099]

Chemical formula

[0100] (wherein Z is selected from the group consisting of silicon or zirconium; R 1 , R 2 , R 3 , and R 4 are each independently selected from the group consisting of alkyl or alkoxy, preferably at least three of R 1 , R 2 , R 3 , and R 4 are alkoxy.);

[0101]

Chemical formula

[0102] (wherein Z is selected from the group consisting of silicon or zirconium; R 5 , R 6 and R 7 It is an alkoxy.

[0103] As described herein, it should be noted that alkoxy groups are reactive functional groups that can participate in the formation of porous composite networks. Alkyl groups typically do not participate in network formation, resulting in unreacted dangling chain ends within the polymer structure.

[0104] In preferred embodiments, the silica alkoxide is selected from the group consisting of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), triethyl vinyl orthosilicate (VTEOS), or substituted derivatives thereof, and / or combinations thereof.

[0105] In preferred embodiments, the alumina alkoxide is selected from the group consisting of aluminum triethoxide, aluminum trimethoxide, aluminum triisopropoxide, or substituted derivatives thereof, and / or combinations thereof.

[0106] In a preferred embodiment, the zirconium alkoxide is selected from the group consisting of zirconium tetraethoxide, zirconium tetramethoxide, zirconium tetraisopropoxide, or substituted derivatives thereof.

[0107] As used herein, the terms “functional end group,” “reactive end group,” and “terminal reactive group” refer to substituents or sites located at the ends of macromolecules or oligomer molecules (e.g., polymer precursor compounds). Such substituents or sites can participate in further polymerization or other reactions. Therefore, a polymer functionalized with at least one reactive group is suitable for reaction with a given compound having at least one complementary reactive functional group.

[0108] Preferably, in this disclosure, silica alkoxide reacts with a polymer precursor compound containing two alkoxysilane-terminated groups; alumina alkoxide reacts with a polymer precursor compound containing two alkoxyaluminum-terminated groups; and zirconium alkoxide reacts with a polymer precursor compound containing two alkoxyzirconium-terminated groups.

[0109] In certain embodiments, the polymer precursor compound comprises one and / or two reactive terminal functional groups.

[0110] In embodiments, the solid electrolyte may include a porous composite network comprising silica and silane-terminated polyethylene glycol (PEG), thereby covalently grafted within the network such that the PEG chains are covalently grafted into the silica. PEG is advantageous for solid electrolytes because it has ethylene oxide groups and high ionic conductivity. Preferably, the PEG includes reactive functional groups at one and / or both ends, for example, an alkoxysilane as the reactive terminal functional group.

[0111] In embodiments, the solid electrolyte may include a porous composite network comprising silica and polytetrahydrofuran (PTHF), wherein the silica and PTHF are covalently grafted within the network such that the PTHF chains are covalently grafted within the silica. PTHF is advantageous for solid electrolytes because it has ethylene oxide groups and high ionic conductivity. Preferably, the PTHF contains reactive functional groups at one and / or both ends, for example, an alkoxysilane as the reactive end functional group.

[0112] In some embodiments, the amount of silane-terminated polymer, preferably PEG and / or PTHF, is at least 1% to at most 15% by weight relative to the total weight of the solid electrolyte. The amounts described are optimal for improving the flexibility of the solid electrolyte having the silane-terminated polymer.

[0113] In some embodiments, the solid electrolyte may include a porous composite network comprising silica, PEG, and PTHF, thereby covalently grafting the PEG and PTHF chains into the silica.

[0114] Figure 1 shows an exemplary graphic representation of the in-situ formation of a composite network containing silica and PEG chains. In particular, according to a preferred embodiment of the electrolyte, a silica scaffold is shown that is linked to PEG chains containing alkoxysilane as a reactive terminal functional group. As described above, the shown embodiment forms a solid electrolyte with improved flexibility and resistance to cracking.

[0115] In one embodiment, the amount of the polymer precursor compound in the solid electrolyte described herein is at least 3% to at most 15% by weight relative to the total weight of the electrolyte. It has been found that this can provide an optimal balance between the flexibility and integrity of the solid electrolyte.

[0116] As mentioned above, solid electrolytes can be manufactured using ionic liquids as the electrolyte. As used herein, “ionic liquid” refers to a low-melting-point salt that is liquid at room temperature and contains cations and anions dissolved in a solvent, and can be used as an electrolyte for energy storage applications depending on the exact anion / cation combination.

[0117] As will be discussed later, to improve ionic conductivity, one or more ionic conductive compounds such as ionic liquids, as well as alternatives such as sulfolane, N-methylacetamide, and tetraethylene glycol dimethyl ether, can be added to the (sol-gel) precursor solution. Low-flammability liquid additives exhibit high dielectric constants, and the strong interaction between the strong electronegativity of the liquid additive and the ions leads to strong dissociation of the metal salt, thus giving the solid electrolyte high ionic conductivity.

[0118] Variations of ion-conducting compounds, such as ionic liquids, are known in the art. For example, as further shown in Figure 1, the solid electrolyte may contain 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI) according to a preferred embodiment of the electrolyte. The use of EMIFSI allows the solid electrolyte to have improved cycling characteristics, rate characteristics, and low-temperature characteristics. Nevertheless, other combinations of conductive compounds and metal salts may be considered, as described below.

[0119] In some embodiments, the metal salt is Li + na + Mg + Ca + , Al+ This may include, and / or combinations thereof. Preferably, the metal salt is Li, which is the industry standard for the manufacture of high-energy solid-state batteries. + and / or Na + It also includes several different metal salts, for example, Li + and / or Na + It can be used.

[0120] In some embodiments, the amount of dissolved metal salt may be at least 10% to at most 20% by weight relative to the total weight of the solid electrolyte. Preferably, the amount of dissolved Li salt in the solid electrolyte may be at least 10% to at most 20% by weight relative to the total weight of the solid electrolyte. The amounts described are advantageous for producing solid-state batteries with improved ion conductivity.

[0121] In some embodiments, the amount of dissolved metal salt concentration may be at least 1 mol / l to at most 2 mol / l. Preferably, the amount of dissolved LiTFSI may be at least 1 mol / l to at most 2 mol / l. Preferably, in embodiments, the amount of dissolved Li salt concentration may be at least 1 mol / l to at most 2 mol / l. Preferably, the amount of dissolved LiTFSI may be at least 1 mol / l to at most 2 mol / l. The amounts described are advantageous for manufacturing solid-state batteries with improved ion conductivity.

[0122] Alternatively, or in combination, lithium salts may contain one or more other cations, such as lithium bis(trifluoromethanesulfonyl)imide (LiFSI), lithium bis(trifluoromethane)sulfonimide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNO3), any substitutions known in the art, and / or combinations thereof. Nevertheless, LiTFSI is preferred because it is more chemically stable in organic solvents. Furthermore, multiple different metal salts, such as LiFSI and LiTFSI, can also be used.

[0123] In some embodiments, the ion-conducting compound may include at least one of the following: ionic liquids including 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI), PrMPyrrTf2N, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIOtf), BMATFSI, EMIB(CN)4, EMITFA, EMIFAP, EMIPF6, EMIBF4, BMPYRFSI, and / or combinations thereof; sulfolane, N-methylacetamide, tetraethylene glycol dimethyl ether, a mixture of 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME), and / or combinations thereof.

[0124] In some embodiments, the amount of ion-conducting compound in the solid electrolyte may be at least 1% by weight and at most 50% by weight relative to the total weight of the solid electrolyte. In some embodiments, the molar ratio of the ionic liquid to the composite network silica is at least 0.5 and at most 3 (ionic liquid to silica). The amounts described are advantageous for the manufacture of solid batteries with improved ion conductivity.

[0125] Preferably, the solid electrolyte according to this disclosure comprises clay mineral particles. As used herein, clay minerals refer to naturally occurring minerals that are abundant in the Earth's crust. They belong to the phyllosilicate group (i.e., hydrated aluminum phyllosilicate) and are characterized by layered and crystalline structures. It has been found that clay minerals with small particle sizes, preferably nanoparticles having a size in the range of 1.0 to 100.0 nm, result in high compatibility between the porous composite network and the clay mineral particles.

[0126] Those skilled in the art will understand that the origin of the clay mineral particles does not play a significant role in the function of the present invention. Therefore, the clay mineral particles may be natural clay mineral particles or synthetic clay minerals produced in an industrial environment through various known processes. Nevertheless, the use of natural clay mineral particles, such as natural halloysite nanotubes (HNTs), may offer advantages in terms of cost-effectiveness and environmental impact in production.

[0127] In preferred embodiments, the clay mineral particles are clay mineral nanoparticles or clay mineral nanostructures. The use of nanoparticles may allow for improved dispersion in liquid or gel mixtures when producing solid electrolytes using any of the methods described herein. This is particularly important when producing thin layers, as any heterogeneity can affect the ionic conductivity of the solid electrolyte by interfering with lithium ion transport pathways. Therefore, the overall ionic properties of the solid electrolyte can be further improved by producing a solid electrolyte with homogeneously dispersed clay mineral nanoparticles. It may be understood that mixtures of clay mineral particles and clay mineral nanoparticles may also be considered.

[0128] In preferred embodiments, the clay mineral particles are clay mineral nanoparticles or clay mineral nanostructures. The use of nanoparticles may allow for improved dispersion in liquid or gel mixtures when producing solid electrolytes using any of the methods described herein. This is particularly relevant when producing thin layers, as any heterogeneity can disrupt favorable lithium ion transport pathways within the solid electrolyte layer. Therefore, the overall ionic properties of the solid electrolyte can be further improved by producing a solid electrolyte with homogeneously dispersed clay mineral nanoparticles. It may be understood that mixtures of clay mineral particles and clay mineral nanoparticles may also be considered.

[0129] In a preferred embodiment, the clay mineral particles are nanoparticles having a fibrous or tubular structure. This has the advantage that the nanoparticles simultaneously reinforce the porous composite network and provide a large surface area for interaction with the ionic liquid, which can result in increased mechanical strength and ionic conductivity of the solid electrolyte.

[0130] In one embodiment, the clay mineral particles include (nano)structures having an elongated shape, such as a fibrous or needle-like structure. This elongated shape can improve absorbency and binding by increasing the surface area available for interaction. Alternatively, the clay mineral particles may include individual nanoparticles aligned in an elongated structure. Preferably, the elongated shape may include nanowires, nanofibers, nanotubes, and / or nanorods.

[0131] In some embodiments, the clay mineral particles include a (nano)structure comprising rolled or tubular layers, which advantageously have a hollow central core or lumen. The external and internal surfaces of the clay mineral particles can be functionalized or modified to enhance compatibility with certain materials, as described in later embodiments.

[0132] In one embodiment, the clay mineral particles include (nano)structures having a tubular shape with a negatively charged exterior and a positively charged interior. While not wishing to be constrained by theory, it has been found that the negatively charged exterior of the clay mineral particles can interact with metal salts contained in ionic liquids. As a result, the clay mineral particles can assist in the dissociation of metal salts, improving the ionic conductivity of the solid electrolyte. Thus, by adding clay mineral particles to a solid electrolyte, the electrochemical and thermal stability can be improved.

[0133] In one embodiment, the clay mineral particles include a (nano)structure having a (nano)tubular shape with a hollow interior. Advantageously, the (nano)tubular shape consists of a plurality of rolled layers, each of which may contain at least two different materials. For example, the tubular shape of the clay mineral may consist of rolled alumina and silica layers, which may be alternating or continuous.

[0134] In one embodiment, the clay mineral particles are selected from the group consisting of palygorskite, attapulgite, kaolin, smectite, illite, chlorite, sepiolite, vermiculite, and mixtures thereof; preferably palygorskite, kaolin, and / or attapulgite.

[0135] In preferred embodiments, the amount of clay mineral particles or nanoparticles is at least 0.1% to at most 10% by weight relative to the total weight of the solid electrolyte, preferably at least 0.5% to at most 10% by weight, and more preferably at least 1.0% to at most 10% by weight relative to the total weight of the solid electrolyte. It has been observed that amounts greater than 10% by weight can lead to the formation of aggregates, which can adversely affect the homogeneous dispersion of the clay mineral particles. Nevertheless, the use of dispersants can be considered to address this problem, and it may be possible to use higher percentages of clay mineral particles, exceeding 10% by weight.

[0136] In some embodiments, the solid electrolyte may include halloysite nanotubes (HNTs). As used herein, halloysite nanotubes refer to tubular 3D nanostructures having oppositely charged surfaces, more specifically, a negatively charged outer surface, e.g., a silica surface, and a positively charged inner surface, e.g., an aluminol surface. In preferred embodiments, the HNTs include aluminosilicate (Al2Si2O5(OH)4).

[0137] In a preferred embodiment, the amount of HNT is at least 0.1% to at most 10% by weight, preferably at least 0.5% to at most 10% by weight, and more preferably at least 1.0% to at most 10% by weight, relative to the total weight of the solid electrolyte. It has been observed that amounts greater than 10% by weight can lead to the formation of aggregates, which can adversely affect the homogeneous dispersion of HNT. Nevertheless, the use of dispersants can be considered to address this problem, and it may be possible to use higher wt% HNTs than 10% by weight.

[0138] When free lithium salts dissolve in the graft polymer chains of a hybrid electrolyte, the mobile anions of the lithium salts move freely to the counter electrode, creating a concentration gradient in the electrolyte. This reduces the lithium ion transport rate, increases polarization, increases internal impedance, and decreases power capability. By introducing HNTs into the solid electrolyte, the counter anions of the lithium salts can be immobilized, and the lithium ion transport rate (t Li+ This can increase the concentration gradient while simultaneously reducing polarization due to the concentration gradient, thereby leading to homogeneous lithium deposition and dissolution.

[0139] Conversely, the charged HNT surface separates lithium salts into lithium cations absorbed by the negatively charged outer silica surface, while anions can be accommodated on the positively charged inner aluminol surface. Therefore, the regular three-dimensional structure for free lithium-ion transport shortens the travel distance of free lithium ions, reduces ion coupling, and provides a fast freeway for lithium-ion transport. Thus, the ionic conductivity and lithium-ion transport rate of the electrolyte are improved. Additional advantages provided by the HNTs in the composite electrolyte of this invention may include enhanced mechanical strength, a high electrochemical stability window, and thermal stability that prevents creep under pressure. Thus, HNTs can offer the potential for sustainable high-energy storage at low cost.

[0140] Figure 2 shows an exemplary graphic representation of in-situ formation of a composite network containing PEG chains and HNTs within porous silica. In particular, the EO units on the PEG chains grafted within the porous composite network have abundant lone pairs of electrons that interact with Li ions on the outer HNT surface as the polymer becomes organized and conforms to the HNTs. Lewis acid-base interactions between the HNTs, Li-TFSI, and PEG effectively order the ions into three-dimensional channels. As mentioned above, these interactions can significantly shorten the travel distance of free Li ions.

[0141] In some embodiments, the amount of HNTs in the solid electrolyte may be at least 0.1% by weight and at most 10% by weight relative to the total weight of the solid electrolyte. The amounts described are optimal for the combination of the rigidity of the solid electrolyte and the amount of HNTs.

[0142] In some embodiments, the amount of HNTs in the solid electrolyte may be at least 0.1% to at most 10% by weight relative to the total weight of the solid electrolyte, and the amount of silane-terminated polymer, preferably PEG and / or PTHF, may be at least 1% to at most 15% by weight. The amounts described are optimal for the combination of the rigidity of HNTs and the flexibility of the silane-terminated polymer.

[0143] Another aspect of this disclosure is, The process involves mixing a silica precursor, a silane-terminated polymer precursor containing polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF), an ion-conducting compound, a metal salt, and a solvent to form a liquid mixture; • A step of gelling a liquid mixture to form a gel mixture; and • A process of drying and / or aging the gel mixture to form a solid electrolyte. This invention relates to a method for producing solid electrolytes, including those mentioned above.

[0144] In another aspect, a method for producing a solid electrolyte, preferably a solid electrolyte as disclosed herein, is: The process involves mixing an alkoxide compound, a polymer precursor compound containing PEG and / or PTHF, an ion-conducting compound, a metal salt, clay mineral particles, and a solvent to form a liquid mixture. • A step of gelling a liquid mixture to form a gel mixture; and • A process of drying and / or aging the gel mixture to form a solid electrolyte. Includes.

[0145] As described above, solid electrolytes can be produced by reacting an alkoxide compound, preferably a silica precursor, with a polymer by a sol-gel process in any of the above embodiments to form porous silica in situ, in which functionalized polyether chains are covalently grafted. It is understood that any of the above embodiments of a solid electrolyte constitute an embodiment of a method for producing a solid electrolyte, and vice versa.

[0146] The “sol-gel process” as referred to herein involves the conversion of a reactive precursor compound into a colloidal suspension (sol), which acts as a precursor for an aggregated network (gel). In particular, the sol-gel process disclosed herein is a wet crosslinking technique, which can be initiated by hydrolysis and / or alcohol decomposition of a silicon precursor in the presence of an organic solvent, which may optionally be included, for example, as a second solvent. The colloidal suspension according to this disclosure may include a branched copolymer, in particular a graft copolymer, in which the main chain mainly comprises (inorganic) silica, and in which the side chains mainly comprise functionalized (organic) polymer chains.

[0147] Accordingly, in certain embodiments, the liquid mixture used to prepare the solid electrolyte composition disclosed herein further comprises a solvent. Preferably, the solvent contains a sufficient amount of water to modify the reactivity of at least a portion of the silicon precursor by hydrolyzing at least a portion of the silicon precursor. The solvent can assist in the mixing and dispersion of the silicon precursor, the ionic liquid electrolyte (ILE), and the organosilicon compound. Furthermore, the solvent can alter the viscosity of the gel mixture, thereby facilitating the handling and processing of the gel mixture for forming the solid electrolyte composition. Preferably, the solvent comprises an aqueous solvent.

[0148] Hydrolysis and / or alcohol decomposition products contained in the liquid mixture can condense and crosslink to form dispersed particles in the liquid mixture. Further condensation or curing can form a three-dimensional network or gel mixture. The wet gel can then be dried or aged to form a preferably solvent-free dry organic-inorganic network. Embedding an ionic liquid electrolyte into the three-dimensional organic-inorganic network yields a solid electrolyte.

[0149] In some embodiments, the mixing of a silica precursor and a silane-terminated polymer precursor involves covalently bonding the polymer compound to the silica precursor so that a porous composite network is formed, thereby covalently grafting the silica and silane-terminated polymer within the network.

[0150] In some embodiments, the mixing of an alumina precursor and an alkoxyaluminum-terminated polymer precursor involves covalently bonding the polymer compound to the alumina precursor so as to form a porous composite network, thereby covalently grafting the alumina and alkoxyaluminum-terminated polymers within the network.

[0151] In some embodiments, the mixing of a zirconium precursor and an alkoxyzirconium-terminated polymer precursor involves covalently bonding the polymer compound to the zirconium precursor so that a porous composite network is formed, thereby covalently grafting the zirconium and alkoxyzirconium-terminated polymers into the network.

[0152] In some embodiments, the polymer precursor compound is given by the following formula:

[0153] [ka]

[0154] (In the formula, TG is a reactive terminal functional group selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof; R is an alkyl group; and n is in the range of 6 to 1300, more preferably 6 to 500, more preferably 6 to 100, even more preferably 6 to 50, and even more preferably 6 to 9. Accordingly, it contains one reactive terminal functional group and one non-reactive terminal functional group.

[0155] In some embodiments, the polymer compound is given by the following formula:

[0156] [ka]

[0157] (In the formula, TG is a reactive terminal functional group, R is an alkyl group, and n is in the range of 6 to 1300, more preferably 6 to 500, more preferably 6 to 100, even more preferably 6 to 50, and even more preferably 6 to 9.) Accordingly, it may contain a reactive functional group at one end.

[0158] In some embodiments, the polymer precursor compound is given by the following formula:

[0159] [ka]

[0160] (In the formula, TG is a reactive terminal functional group selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof; ·R is an alkyl group, and n is in the range of 6 to 13000, preferably 6 to 10000, more preferably 6 to 5000, even more preferably 6 to 1000, even more preferably 6 to 500, and even more preferably 6 to 150. Accordingly, it contains two reactive terminal functional groups.

[0161] In some embodiments, the polymer compound is given by the following formula:

[0162] [ka]

[0163] (In the formula, TG is a reactive terminal functional group, R is an alkyl group, and n is in the range of 6 to 13000, preferably 6 to 10000, more preferably 6 to 5000, even more preferably 6 to 1000, even more preferably 6 to 500, and even more preferably 6 to 150.) Accordingly, it may contain functional groups at both ends of the reactive structure.

[0164] In some embodiments, the polymer compound may comprise a combination of two or more polymer compounds containing functional groups at different reactive terminal ends. For example, the polymer compound may comprise two or more polymer compounds containing functional groups at one terminal end with a different reactiveity. Alternatively, or in combination, the polymer compound may comprise two or more polymer compounds containing functional groups at both terminal ends with different reactiveities.

[0165] In some embodiments, the polymer compound may include a combination of two or more polymer compounds, where at least one polymer includes a reactive single-ended functional group according to, for example, any of the embodiments described above, and at least one polymer includes reactive double-ended functional groups according to, for example, any of the embodiments described above.

[0166] In some embodiments, the methods disclosed herein include combinations of two or more polymer compounds; in which at least one polymer preferably comprises one reactive terminal functional group and one non-reactive terminal functional group according to any of the above embodiments, and at least one polymer preferably comprises two reactive terminal functional groups according to any of the above embodiments.

[0167] In some embodiments, the amount of polymer compound, preferably PEG and / or PTHF, in the liquid mixture is at least 1% by weight and at most 15% by weight relative to the total weight of the solid electrolyte.

[0168] In some embodiments, the silica precursor may include silicon alkoxides, preferably tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), triethyl vinyl orthosilicate (VTEOS), or their substituted derivatives, and / or combinations thereof. It can be understood that, in principle, any silicon alkoxide can be considered as a silica precursor in the mixture. Substitution of ethoxy / methoxy groups in the silicon alkoxide leads to changes in the morphology / propriety of the resulting silica, and thus the properties of the composite network can be adjusted to some extent. Those skilled in the art will understand how this selection can be made.

[0169] In some embodiments, the amount of silica precursor in the liquid mixture may be at least 10% to at most 25% by weight relative to the total weight of the solid electrolyte. The amounts described are advantageous for the production of solid batteries with good structural properties.

[0170] In certain embodiments, the silica precursor may be omitted from the mixture. The solid electrolyte can be prepared based on a combination of silane-terminated polymers, i.e., silicon alkoxide-free precursor compounds such as TEOS, VTEOS, or TMOS.

[0171] In some embodiments, the ion-conducting compounds may include ionic liquids comprising EMIFSI, EMITFSI, PrMPyrrTf2N, EMIOtf, BMATFSI, EMIB(CN)4, EMITFA, EMIFAP, EMIPF6, EMIBF4, BMPYRFSI and / or combinations thereof, sulfolanes, N-methylacetamide, tetraethylene glycol dimethyl ether, mixtures of 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME), and / or combinations thereof.

[0172] In some embodiments, the amount of the ion-conducting compound in the liquid mixture may be at least 1% by weight and at most 50% by weight relative to the total weight of the solid electrolyte. The amounts described are advantageous for the production of solid-state batteries with improved ion conductivity.

[0173] In some embodiments, the metal salt is Li + na + Mg + Ca + , Al + , and / or at least one combination thereof. Preferably the metal salt is Li, which is the industry standard for the manufacture of high-energy solid-state batteries. + and / or Na + Includes.

[0174] In some embodiments, the amount of dissolved metal salt in the liquid mixture may be at least 1 mol / l to at most 2 mol / l. Preferably, the amount of dissolved LiTFSI may be at least 1 mol / l to at most 2 mol / l. Preferably, in embodiments, the amount of dissolved Li salt may be at least 1 mol / l to at most 2 mol / l. Preferably, the amount of dissolved LiTFSI may be at least 1 mol / l to at most 2 mol / l. The amounts described are advantageous for manufacturing solid-state batteries with improved ion conductivity.

[0175] Returning to the gelation method, a liquid mixture can be formed by placing all the precursor compounds and additives in a container and mixing them with a solvent at a low temperature. The solvent can be any organic solvent suitable for dissolving the precursor compounds and additives. For example, the solvent may be an organic solvent containing water and / or alcohol, such as isopropanol, ethanol, 1-methoxy-2-propanol, etc. Advantageously, the liquid mixture is stirred, for example, using a magnetic stirrer, until all components are completely dissolved.

[0176] Subsequently, a gel mixture can be formed by the gelation of the liquid mixture. Gelation can be achieved by storage in a storage room. For example, a container containing the liquid mixture can be sealed and stored at room temperature (25°C, ambient temperature) for several days, during which time the liquid mixture will transform into a wet gel mixture.

[0177] The time required for gelation can be controlled by the amount of water added, the amount of organic solvent added, and the storage temperature. In some embodiments, gelation can be carried out at temperatures of at most 70°C to at least 30°C, preferably at most 60°C to at least 40°C, more preferably at most 55°C to at least 45°C, and even more preferably at about 50°C. The temperatures described can reduce the time required for gelation to occur, but lower temperatures can also be considered.

[0178] After gelation, a solid electrolyte can be formed by drying the wet gel mixture. Drying can be carried out by classical drying and / or aging processes. For example, the gel mixture can be dried using a vacuum dryer under conditions of a pressure of 0.1 to 200 Pa and a temperature of 15 to 100°C (ambient temperature). Optionally, a pre-drying process can be performed before the vacuum drying process to suppress bumping and bubble formation during vacuum drying. In the pre-drying process, the gel mixture is heated using a hot plate, for example, in a local exhaust system, under conditions of atmospheric pressure and a temperature of 15 to 90°C (surface temperature of the hot plate). Most of the water and organic solvents contained in the gel mixture can be evaporated by the pre-drying process.

[0179] During gelation, the solid electrolyte can be impregnated into the pores of the electrode layer. The liquid mixture may partially gel before impregnation of the electrode layer. When heated at low temperatures, the liquid mixture slightly gels, and then the pre-gelated mixture is blade-coated onto the electrode layer, resulting in the formation of a gel mixture within the pores of the active electrode.

[0180] Another aspect of this disclosure relates to an electrode comprising an electrode active material and a solid electrolyte according to any of the embodiments described above. In this way, a composite electrode can be obtained. Preferably, the solid electrolyte may cover and / or coat the surface of the electrode active material as a coating layer, as described later.

[0181] For example, electrode active material can be manufactured by applying a slurry containing active material particles, a binder, and conductive agent particles onto a current collector. The slurry can be applied using coating techniques known in the art, such as drop casting, blade coating, slot die coating, or spray coating. The slurry can then be dried to obtain the electrode active material on top of the current collector.

[0182] Subsequently, the electrode active material can be impregnated, for example, by coating it with a solid electrolyte precursor solution and / or a pregelled electrolyte solution. In this way, a composite electrode containing a composite electrolyte can be obtained with or without overfill. Impregnation with the solid electrolyte precursor and / or pregelled electrolyte solution can be carried out using coating techniques known in the art, such as drop casting, blade coating, slot die coating, spray coating, etc. The amount of solid electrolyte precursor and / or pregelled electrolyte solution can be adjusted, for example, to form or not form an overfill on the top of the composite electrode. Those skilled in the art will understand that exemplary embodiments can be adapted based on the relevant assembly process strategy.

[0183] Furthermore, due to the improved properties of the solid electrolytes disclosed herein, it can be understood that there is potential to adapt the manufacturing process to produce self-supporting membranes, which was previously difficult with other types of solid electrolytes, such as pure porous silica. Nevertheless, solid electrolytes can also be manufactured using classical manufacturing techniques as described above, allowing for greater adaptability based on the relevant assembly process strategy.

[0184] As described above, the solid electrolyte of this disclosure can exhibit improved ionic conductivity, and therefore, electrodes containing the solid electrolyte can also exhibit improved ionic conductivity. Similarly, the electrode may have improved mechanical properties due to the improved flexibility of the solid electrolyte. It is understood that any of the above embodiments of the solid electrolyte constitutes an embodiment of the electrode.

[0185] The improved structural properties can be particularly advantageous in electrode manufacturing by reducing the likelihood of the material becoming brittle and breaking. In particular, it becomes possible to bend and roll electrodes impregnated with a solid electrolyte and / or covered with an overfill of a solid electrolyte. Thus, the size of the electrodes can be increased by coating them on larger size and extremely large surface areas of substrates.

[0186] The terms “covering” or “coating” are used to refer to a point or position in which the electrode active material comes into contact with the solid electrolyte and forms a layer that covers and / or coats the electrode active material, more specifically on one or more of its surfaces, according to any of the embodiments described above. Advantageously, the layer completely covers at least one surface of the electrode active material.

[0187] In some embodiments, the solid electrolyte may be a uniform coating layer on the electrode active material. As used herein with respect to the composite layer, “uniform” means that the layer does not contain segregated regions of amorphous and / or crystalline content that can be readily identified using the analytical techniques described herein.

[0188] In some embodiments, the solid electrolyte may be a homogeneous coating layer on the electrode active material. The term "homogeneous" as used herein for a composite layer means that, according to any of the embodiments described herein, the components of the layer, more specifically silica and polymer compounds, are homogeneously mixed, and that the layer and / or its surface does not contain any areas where the components can be readily identified using the analytical techniques described herein.

[0189] In some embodiments, the coating layer may have a dry thickness before compression of less than about 200 μm, preferably less than about 150 μm, more preferably less than about 100 μm, and even more preferably less than about 60 μm, for example, 50 μm, 40 μm, or 30 μm.

[0190] In some embodiments, the thickness of the coating layer, preferably as an overfill solid electrolyte, may be between 0 μm and 1000 μm, preferably between 0 μm and 300 μm, more preferably between 0 μm and 100 μm, and even more preferably between 0 μm and 30 μm. The thickness of the coating layer can affect the ionic properties of the battery, and those skilled in the art will understand that the thicknesses of the exemplary embodiments described herein may be adapted based on the relevant assembly process strategy.

[0191] As used herein, a “thick” film refers to an electrolyte film having a layer thickness greater than approximately 50 μm after drying, and a “thin” film refers to an electrolyte film having a layer thickness less than approximately 50 μm after drying. Advantageously, the thickness of the solid electrolyte after compression is manufactured to be as thin as possible while maintaining the mechanical function (crack-free) of separating the positive and negative electrodes from each other, so as to achieve maximum Wh / L at the device and stack levels. Nevertheless, it should be understood that the composite electrolytes disclosed herein have the advantage, as described above, of enabling the manufacture of thick / thin films of various thicknesses and diameters, enabling the manufacture of large and / or thick self-supporting films, or yielding crack-free films of several μm (e.g., in the range of >20 μm and <150 μm on the top of the electrodes).

[0192] Alternatively, or in combination with any of the embodiments described above, the solid electrolyte may be a self-supporting membrane. Preferably, the solid electrolyte is a homogeneous / uniform self-supporting membrane. The improved mechanical properties of the solid electrolyte make it possible to cast a membrane onto the electrodes, preferably between two opposing electrodes. The self-supporting membrane can be manufactured by depositing it on a substrate that is removed after the solid electrolyte has solidified.

[0193] In some embodiments, the electrode active material used in the electrode may be the positive electrode active material. Examples of positive electrode active materials may include lithium-containing transition metal oxides, vanadium oxide, chromium oxide, and lithium-containing transition metal sulfides. Examples of lithium-containing transition metal oxides are LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNiCoMnO2 (referred to as the NMC family, having various compositions NMXxyz, where x, y, and z refer to the relative amounts of Ni, Mn, and Co present in the cathode active material; for example, NMC111 has Ni 33.33%; Mn 33.3% and Co This corresponds to a material consisting of 3.33% (or NMC532, NMC622, NMC721, NMC811, NMC90.50.5, and other NMC compositions, or combinations thereof), LiNiCoO2, LiCoMnO2, LiNiMnO2, LiNiCoMnO4, LiMnNiO4, LiMnCoO4, LiNiCoAlO2, LiNiPO4, LiCoPO4, LiMnPO4, LiFePO4, LiMnFePO4, Li2NiSiO4, Li2CoSiO4, Li2MnSiO4, Li2FeSiO4, LiNiBO3, LiCoBO3, LiMnBO3, and LiFeBO3. Examples of lithium-containing transition metal sulfides include LiTiS2, Li2TiS3, and Li3NbS4. One or more positive electrode active materials selected from these positive electrode active materials can be used.

[0194] In some embodiments, the electrode active material used in the electrode may be the negative electrode active material. Examples of negative electrode active materials may include metals, metalloids, oxides, nitrides, and carbon. Examples of metals and metalloids include lithium, silicon, amorphous silicon, aluminum, silver, tin, antimony, and alloys thereof. An example of an oxide is Li4Ti5O 12 Li2SrTi6O 14These may include TiO2, Nb2O5, SnO2, Ta2O5, WO2, WO3, Fe2O3, CoO, MoO2, SiO2, SnBPO6, and mixtures thereof. Examples of nitrides may include LiCoN, Li3FeN2, Li7MnN4, and mixtures thereof. Examples of carbon include graphite, graphene, hard carbon, carbon nanotubes, and mixtures thereof. One negative electrode active material selected from these negative electrode active materials, or two or more negative electrode active materials, can be used.

[0195] In some embodiments, the electrodes may include a binder. The binder can fix the particles of the electrode active material together. When the particles of the electrode active material are fixed together, the generation of gaps due to the expansion and contraction of the electrode active material particles is suppressed. This suppresses a decrease in the discharge capacity of the battery containing the electrodes. The binder may include, for example, carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), and the like.

[0196] Another aspect of this disclosure is, • A process of providing an electrode active material; and • A step of forming a coating layer containing a solid electrolyte on an electrode active material according to any of the above embodiments. This relates to a method for manufacturing electrodes, including the invention of an electrode.

[0197] In some embodiments, electrode active material can be produced by applying a slurry containing active material particles, a binder, and conductive particles onto a current collector, and drying the slurry to obtain electrode active material on top of the current collector. Preferably, the slurry is applied using drop casting, blade coating, slot die coating, and / or spray coating.

[0198] In some embodiments, the electrode active material can be impregnated with a solid electrolyte by coating it with a solid electrolyte precursor solution and / or a pregelled electrolyte solution and then drying the impregnated electrode active material. Preferably, impregnation is applied using drop casting, blade coating, slot die coating, and / or spray coating. Advantageously, the amount of solid electrolyte precursor and / or pregelled electrolyte solution is adapted based on the relevant assembly process strategy so as not to form an overfill on top of the composite electrode.

[0199] In some embodiments, the method may include the steps of: producing a self-supporting membrane containing a solid electrolyte according to any of the above embodiments; and arranging the self-supporting membrane on an electrode active material. Preferably, the self-supporting membrane can be produced by depositing a solid electrolyte precursor solution and / or a pre-gelled electrolyte solution onto a substrate, and removing the substrate after the precursor solution has solidified.

[0200] Another aspect of this disclosure relates to electrochemical energy storage devices, such as batteries or cells, comprising a positive electrode, a negative electrode, and a solid electrolyte, according to any of the embodiments described above. It is understood that electrochemical energy storage devices may include various combinations of electrodes, for example, multiple negative and positive electrodes advantageously stacked on top of each other. Techniques for manufacturing power storage devices from solid electrolytes are known in the art.

[0201] As used herein, “electrochemical energy storage device” means a device that generates electrical energy from a chemical reaction or can use electrical energy to induce a chemical reaction. The technologies of this disclosure can be considered general-purpose technologies in that they can be readily adapted to a wide variety of different electrochemical energy storage devices, including solid-state electrochemistry, which can be implemented in a wide variety of battery applications, such as, but not limited to, automotive, aerospace, marine, and space.

[0202] In some embodiments, the electrochemical energy storage device may include a solid electrolyte as a self-supporting membrane located on at least one electrode, preferably between two opposing electrodes.

[0203] As described above, the solid electrolytes of this disclosure can exhibit improved ionic conductivity; therefore, a power storage device including an electrode having the solid electrolyte can also exhibit improved ionic conductivity. Similarly, the power storage device may have improved mechanical properties due to the improved flexibility of the solid electrolyte contained in the electrode. It is understood that any of the above embodiments of the solid electrolyte constitute an embodiment of a power storage device. [Examples]

[0204] Examples Examples of an implementation of the technology described herein are shown below. The examples are intended to help readers more easily understand the technical concepts, but are not intended to identify their most important or essential features, nor are they intended to limit the scope of this disclosure.

[0205] Throughout the examples, the following abbreviations are used: silane-terminated polyethylene glycol (SPEG); halloysite nanotube (HNT); tetraethoxysilane (TEOS); 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI); lithium bis(trifluoromethanesulfonyl)imide (LiTFSI); lithium nickel manganese cobalt oxide (NMC) cathode; lithium iron phosphate (LFP); thermogravimetric analysis (TGA); scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS).

[0206] Example 1: Mechanical performance To demonstrate the improved mechanical properties of the composite electrolytes disclosed herein, a number of solid electrolyte membranes are manufactured using drop casting of electrolyte solutions prepared by a sol-gel process based on the following process parameters: • Gelation of liquid mixtures at 50°C; • Drop casting of electrolyte solution into the cap of a coin cell battery; Drying of the gel mixture under vacuum at 60°C.

[0207] For the liquid mixture, TEOS is used as the silicon precursor and SPEG as the silane-terminated polymer precursor to produce a composite porous silica network. The relative concentrations of each electrolyte membrane are shown below. HNTs are used as clay mineral particles to be included in the composite porous silica network.

[0208] In the first part of this embodiment, three different electrolyte membranes are prepared, each containing a pure silica electrolyte (reference), a composite electrolyte containing 5.0 wt% SPEG, and a composite electrolyte containing 10.0 wt% SPEG. The wt% of SPEG is calculated in comparison to the total weight of the solid electrolyte. The quality of the electrolyte membranes was visually inspected for the presence of stress cracks.

[0209] Figure 3 shows the results for a pure silica electrolyte film. The solid electrolyte exhibits brittle mechanical behavior, and stress cracks are observed throughout the coating film.

[0210] Figure 4 shows the results for a composite electrolyte membrane containing 5% by weight of SPEG. It can be seen that the composite electrolyte can form a uniform membrane with improved mechanical properties and no cracks.

[0211] Figure 5 shows the results for a composite electrolyte membrane containing 10% by weight of SPEG. It can be seen that the composite electrolyte can form a uniform membrane with improved mechanical properties and no cracks.

[0212] To further demonstrate the applicability of the electrolyte solution as a self-supporting membrane, two self-supporting membranes were prepared using drop casting of the composite electrolyte solution prepared by the sol-gel process described above: one composite electrolyte membrane containing 5.0 wt% SPEG, and another composite electrolyte membrane containing 10.0 wt% SPEG and 0.5 wt% HNT.

[0213] Figure 6 shows the results for a composite electrolyte membrane containing 5.0 wt% SPEG. It can be seen that the composite electrolyte can form a stable, self-supporting membrane without cracks.

[0214] Figure 7 shows the results for a self-supporting composite electrolyte membrane containing 10 wt% SPEG and 0.5 wt% HNT. It can be seen that the composite electrolyte can form a uniform membrane without cracks.

[0215] To further demonstrate the resilience of the solid composite electrolyte when incorporated into and on top of a porous composite electrode, another membrane is prepared using drop casting of a composite electrolyte solution containing 7 wt% SPEG + 1 wt% HNT. The thickness of the dry composite electrolyte membrane (dry overfill) on top of the porous composite cathode containing the NMC cathode active material is 200 μm. The resilience of the electrolyte membrane is manually inspected by bending tests.

[0216] Figure 8 shows the results of drop-casting a composite electrolyte membrane onto the top of a porous composite cathode. The 200 μm thick membrane remained intact after bending, demonstrating high mechanical stability.

[0217] To further understand the applicability of electrolyte solutions as dry electrolyte membranes, two electrolyte membranes were prepared by blade coating a pure silica electrolyte and a composite electrolyte containing 3 wt% SPEG onto the top of an NMC cathode. The wt% of SPEG was calculated in comparison to the total weight of the solid electrolyte. The uniformity of the membrane was examined by SEM.

[0218] Figure 9 is an SEM image of the overfill portion of a 14 μm thin film of pure silica electrolyte, with a crack-free area selected for the image. It can be seen that this thin film lacks uniformity, and increasing the film thickness and / or size may lead to crack formation. This is the thickest pure silica electrolyte film that could be formed without cracking.

[0219] Figure 10 shows an SEM image of the overfill portion of a 78 μm thick film of a composite electrolyte containing 3 wt% SPEG. Compared to the film in Figure 6, it can be seen that the uniformity of the film has improved despite its greater thickness. Therefore, using silane PEG containing silica as a composite electrolyte may enable the formation of uniform thin / thick self-supporting films without crack formation.

[0220] Figure 11 shows an SEM image of the overfill portion of a 96 μm thick composite electrolyte membrane containing 10 wt% SPEG and 3 wt% HNT. It can be seen that a uniform, crack-free membrane has formed even thicker.

[0221] The above results demonstrate that it is possible to form thick films (e.g., 78–96 μm) using a composite electrolyte. Such large thicknesses cannot be achieved using a pure silica electrolyte solution, where the maximum measured thickness is 14 μm.

[0222] Example 2: Ionic Conductivity Performance To demonstrate the improved properties of the composite electrolytes disclosed herein, a number of electrolyte membranes are prepared using drop casting of electrolyte solutions prepared by the sol-gel process described in Example 1.

[0223] In the first part of this embodiment, five different electrolyte membranes are prepared, each containing a pure silica electrolyte (reference), a composite electrolyte containing 5.0 wt% SPEG, a composite electrolyte containing 0.5 wt% HNT, a composite electrolyte containing 7.0 wt% SPEG and 1.0 wt% HNT, and a composite electrolyte containing 10.0 wt% SPEG and 0.8 wt% HNT. The wt% of SPEG and / or HNT is calculated in comparison to the total weight of the solid electrolyte.

[0224] The ionic conductivity of the electrolyte membrane is evaluated using EIS without applying pressure. Each electrolyte membrane is sandwiched between stainless steel (SS) disks (d=1.5cm) to form a symmetric [SS / electrolyte / SS] cell.

[0225] Figure 12 shows the ionic conductivity (mS / cm) of each electrolyte membrane. Specifically, the pure silica electrolyte was measured to have an ionic conductivity of 0.8 mS / cm, the composite electrolyte containing 5.0 wt% SPEG was 1.3 mS / cm, the composite electrolyte containing 0.5 wt% HNT was 1.53 mS / cm, the composite electrolyte containing 7.0 wt% SPEG and 1.0 wt% HNT was 1.5 mS / cm, and the composite electrolyte containing 10.0 wt% SPEG and 0.8 wt% HNT was 1.7 mS / cm.

[0226] From these results, it can be seen that composite electrolytes containing different amounts of SPEG and HNT exhibit higher ionic conductivity compared to pure silica electrolytes. This improvement in ionic conductivity can be attributed to the addition of SPEG and / or HNT to the solid electrolyte.

[0227] To further demonstrate the improvement in ionic conductivity, three additional solutions are prepared: a pure silica electrolyte (reference), a composite electrolyte containing 10.0 wt% SPEG, and a composite electrolyte containing 10.0 wt% SPEG and 0.8 wt% HNT. The wt% of SPEG and / or HNT is calculated in comparison to the total weight of the solid electrolyte. The ionic conductivity of the electrolyte membrane is measured by EIS using the above parameters without applying pressure.

[0228] Figure 13 shows the ionic conductivity (mS / cm) of each electrolyte membrane. Specifically, the pure silica electrolyte was measured to have an ionic conductivity of 0.8 mS / cm, the composite electrolyte containing 10.0 wt.% was 0.62 mS / cm, and the composite electrolyte containing 10.0 wt.% SPEG and 0.8 wt.% HNT was 1.7 mS / cm.

[0229] The above results demonstrate the observed role of HNTs in improving the ionic conductivity of the composite electrolyte. However, it should be noted that the composite electrolyte containing 10 wt% SPEG has relatively less Li salt in the solution than the composite electrolyte containing 5 wt% SPEG. Therefore, its ionic conductivity can be expected to be relatively low.

[0230] To further demonstrate the applicability of the electrolyte solution as a dry electrolyte membrane under pressure, two additional solutions were prepared: a pure silica electrolyte (reference) and a composite electrolyte containing 3 wt% SPEG and 3.0 wt% HNT. The ionic conductivity of the electrolyte membrane was measured using EIS with the above parameters and varying degrees of applied compression pressure.

[0231] Figure 14 shows the ionic conductivity (mS / cm) of the electrolyte membrane as a function of different compression pressures (thickness %). Specifically, for the pure silica electrolyte, an ionic conductivity of 0.8 mS / cm was measured without pressure (thickness 100%), 1.56 mS / cm was measured with moderate pressure (thickness 80%), and 2.39 mS / cm was measured with high pressure (thickness 60%). Furthermore, for the composite electrolyte containing 3.0 wt% SPEG and 3.0 wt% HNT, an ionic conductivity of 1.51 mS / cm was measured without pressure (thickness 100%), 2.54 mS / cm was measured with moderate pressure (thickness 80%), and 3.80 mS / cm was measured with high pressure (thickness 60%).

[0232] From these results, it can be seen that the composite electrolyte exhibits higher ionic conductivity compared to the pure silica electrolyte across all measured pressure ranges.

[0233] Furthermore, an attempt was made to test the electrolyte membrane shown in Figure 14 under ultra-high pressure (40% thickness). However, this caused cracks in the pure silica electrolyte. The quality of the electrolyte membrane after 40% compression was inspected visually, as detailed below.

[0234] Figure 15 shows the results for a pure silica electrolyte membrane after 40% compression. It can be seen that the solid electrolyte is destroyed by the propagation of stress cracks throughout the electrolyte membrane.

[0235] Figure 16 shows the results after 40% compression of a composite electrolyte membrane containing 3 wt% SPEG and 3.0 wt% HNT. The composite electrolyte remains intact even after 40% compression, demonstrating the high mechanical stability of the composite electrolyte membrane.

[0236] Example 3: Thermal Performance To demonstrate the improved thermal properties of the composite electrolytes described herein, a number of electrolyte membranes are prepared using drop casting of electrolyte solutions prepared by the sol-gel process described in Example 1.

[0237] In the first part of this embodiment, three different solutions are prepared, each containing a pure silica electrolyte (reference), pure HNTs (reference), and a composite electrolyte containing 3.0 wt% HNTs. The wt% of HNTs is calculated in comparison to the total weight of the solid electrolyte. Thermal degradation of the membrane is measured using TGA. The TGA profile, including a heating rate of 5°C / min up to 600°C, is performed under nitrogen gas.

[0238] Figure 17 shows the thermal degradation of the electrolyte membrane in the temperature range of 0–600°C. Below 123°C, the curves for the three electrolyte membranes overlap, and the weight loss is approximately 2%. This may be due to water loss. The main degradation of the electrolyte between approximately 123 and 450°C corresponds to the decomposition of the ionic liquid and LiTFSI. The residual values ​​of the pure silica electrolyte and the composite electrolyte are 72% and 84% respectively at 300°C, and this 12% difference is due to the thermal stability of HNTs.

[0239] The results above indicate that HNTs are stable up to approximately 400°C with only a 2% weight loss. Furthermore, the 87% retention above 600°C may be due to Al2O3 and SiO2 nanoparticles. Thus, the addition of HNTs further enhances the thermal stability of the composite electrolyte.

[0240] In the second part of this example, two additional solutions are prepared: a composite electrolyte containing 5.0 wt% SPEG and a composite electrolyte containing 5.0 wt% SPEG and 0.5 wt% HNT. The wt% of SPEG and / or HNT is calculated relative to the total weight of the solid electrolyte. Also, the thermal profiles of pure silica electrolyte, pure SPEG, and pure HNT are included for reference. The thermal degradation of the electrolyte membrane is measured using TGA with the same profile.

[0241] Figure 18 shows the thermal degradation of the electrolyte membrane in the temperature range of 50 - 600 °C. Below 134 °C, the curves of the five electrolyte membranes overlap, and the weight loss is about 2%. This could be due to the loss of water. The main degradation of the electrolyte from about 134 - 450 °C corresponds to the decomposition of SPEG, ionic liquid, and LiTFSI. The main thermal degradation of the pure silica electrolyte, the composite electrolyte containing 5% SPEG, and the composite electrolyte containing 5% SPEG + 0.5% HNT starts at 134 °C, 148 °C, and 159 °C respectively, and the differences of 14 °C and 25 °C are due to the thermal stability of SPEG and HNT.

[0242] It can be seen that SPEG and HNT are stable up to about 195 °C and about 400 °C respectively, with weight losses of only 3% and 2% respectively. Thus, with the addition of SPEG and HNT, the composite electrolyte further exhibits strong thermal stability.

[0243] Example 4: Electrochemical performance To demonstrate the improved electrochemical performance of the composite electrolyte disclosed herein, a full cell battery based on a stack of Li metal (200 μm), a self - standing film (730 μm) of a composite electrolyte containing 5.0 wt% SPEG and 1.0 wt% HNT, and LiFePO4 is fabricated. The wt% of HNT is calculated relative to the total weight of the solid electrolyte. The solid electrolyte is prepared using drop casting of the electrolyte solution prepared by the sol - gel process described in Example 1. The charge / discharge test of the Li / composite electrolyte / LiFePO4 battery is carried out at 0.1 °C and 2.5 - 3.8 V using a NEWARE battery test system.

[0244] Figure 19 shows the 1st, 2nd, and 100 (100) current rates at a room temperature of 0.1C. th The charge / discharge voltage curves of the battery over 100 cycles are shown. Typical discharge and charge plateaus are observed, suggesting good stability of LiFePO4 during the cycles. Initial discharge and charge capacities are 127 mAh / g and 120 mAh / g at cycles 1 and 100, respectively.

[0245] In the first cycle, the initial cycle potential plateau is 3.5V during the charging process and 3.34V during the discharging process, showing small polarization with a voltage difference of only 160mV between charging and discharging. The voltage difference increases slightly after 100 cycles, suggesting that the composite electrolyte provides mobile Li ions, as well as a stable interface between the electrolyte and the electrode.

[0246] Figure 20 shows the long-term cycle performance of the battery at room temperature. A Li metal / LiFePO4 full battery containing a composite electrolyte operates efficiently over long-term cycles (100 cycles) at room temperature and 0.1C.

[0247] The battery, still in the cycle, exhibits a stable discharge capacity of 120 mAh / g after 100 discharge / charge cycles, retaining 95% of its initial discharge capacity, and achieving near 100% efficiency in each cycle.

Claims

1. A solid electrolyte for an electrochemical energy storage device comprising a porous composite network obtained by the reaction of an alkoxide compound and a polymer precursor compound; Among these, the alkoxide compound is selected from the group consisting of silica alkoxide, alumina alkoxide, zirconium alkoxide, and mixtures thereof; Among these, the polymer precursor compound contains two terminal functional groups, and at least one of these terminal functional groups is selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof; Among these, the polymer precursor compound comprises polyethylene glycol (PEG) and / or polytetrahydrofuran (PTHF); Within this, the porous composite network is functionalized with an electrolyte containing an ion-conducting compound in which a metal salt is dissolved; and, Within this, the porous composite network contains a solid electrolyte with clay mineral particles.

2. The solid electrolyte according to claim 1, wherein the clay mineral particles preferably include nanoparticles having an elongated shape, such as nanowires, nanofibers, nanowires, nanotubes, and / or nanorods.

3. The solid electrolyte according to any one of the claims, comprising clay mineral particles having a tubular or nanotubular shape with a negatively charged exterior and a positively charged hollow interior.

4. The solid electrolyte according to any one of the claims, comprising clay mineral particles, a structure having a tubular or nanotubular shape including a plurality of roll-shaped layers, wherein at least two of the roll-shaped layers include different materials.

5. The solid electrolyte according to any one of the claims, wherein the clay mineral particles are selected from the group consisting of palygorskite, attapulgite, kaolin, smectite, illite, chlorite, sepiolite, vermiculite, and mixtures thereof; preferably palygorskite, kaolin, and / or attapulgite.

6. Clay mineral particles, aluminosilicate (Al ２ Si ２ O ５ (OH) ４ A solid electrolyte according to any one of the claims, comprising halloysite nanotubes (HNTs) containing ).

7. The solid electrolyte according to any one of the claims, wherein the amount of clay mineral particles is at least 0.1% by weight to at most 10% by weight, preferably at least 0.5% by weight to at most 10% by weight, relative to the total weight of the solid electrolyte.

8. The solid electrolyte according to any one of the claims, wherein the silica alkoxide is selected from the group consisting of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), triethyl vinyl orthosilicate (VTEOS), or substituted products thereof, and / or combinations thereof.

9. The solid electrolyte according to any one of the claims, wherein the alumina alkoxide is selected from the group consisting of aluminum triethoxide, aluminum trimethoxide, aluminum triisopropoxide, or substituted products thereof, and / or combinations thereof.

10. The solid electrolyte according to any one of the claims, wherein the zirconium alkoxide is selected from the group consisting of zirconium tetraethoxide, zirconium tetramethoxide, zirconium tetraisopropoxide, or substituted products thereof, and / or combinations thereof.

11. The solid electrolyte according to any one of the claims, wherein the porous composite network is an inorganic-organic hybrid network, and preferably comprises a copolymer of an alkoxide compound and a polymer precursor compound.

12. The solid electrolyte according to any one of the claims, wherein the polymer precursor compound comprises one and / or two reactive terminal functional groups.

13. The solid electrolyte according to any one of the claims, wherein the amount of the polymer precursor compound is at least 3% by weight and at most 15% by weight relative to the total weight of the electrolyte.

14. An electrode comprising a solid electrolyte and an electrode active material according to any one of the above claims.

15. The solid electrolyte forms a coating and / or layer on the electrode active material; Preferably, the electrode according to claim 14, wherein the coating layer is a uniform and / or homogeneous coating layer having a preferred thickness after drying and before compression of less than about 200 μm, more preferably less than about 150 μm, even more preferably less than about 100 μm, and even more preferably less than about 60 μm.

16. The solid electrolyte comprises a positive electrode, a negative electrode, and any one of claims 1 to 13; Preferably, an electrochemical energy storage device wherein a solid electrolyte forms a coating and / or layer on at least the positive electrode.

17. - A step of mixing an alkoxide compound selected from the group consisting of silica alkoxide, alumina alkoxide, zirconium alkoxide, and mixtures thereof, a polymer precursor compound containing PEG and / or PTHF (wherein the polymer precursor compound contains two terminal functional groups, at least one of which is selected from the group consisting of alkoxysilane, alkoxyaluminum, alkoxyzirconium, and combinations thereof), an ion-conducting compound, a metal salt, clay mineral particles, and a solvent to form a liquid mixture; - A step of gelling a liquid mixture to form a gel mixture; and - A process of drying and / or aging the gel mixture to form a solid electrolyte. A method for producing a solid electrolyte, preferably the solid electrolyte described in any one of claims 1 to 13.

18. The method according to claim 17, wherein the clay mineral particles preferably include nanoparticles having an elongated shape, such as nanowires, nanofibers, nanowires, nanotubes, and / or nanorods.

19. The method according to any one of claims 17 or 18, comprising a structure having a tubular or nanotubular shape with a negatively charged exterior and a positively charged hollow interior, wherein the clay mineral particles are included.

20. The method according to any one of claims 17 to 19, comprising a structure having a tubular or nanotubular shape including a plurality of roll-like layers, wherein at least two of the layers include different materials.

21. The method according to any one of claims 17 to 20, wherein the clay mineral particles are palygorskite, attapulgite, kaolin, smectite, illite, chlorite, sepiolite, vermiculite, and mixtures thereof; preferably selected from the group consisting of palygorskite, kaolin and / or attapulgite.

22. Clay mineral particles, aluminosilicate (Al ２ Si ２ O ５ (OH) ４ The method according to any one of claims 17 to 21, comprising halloysite nanotubes (HNTs) containing ).

23. The polymer precursor compound is given by the following formula: 【Chemistry 1】 (In the formula, TG is a reactive terminal functional group selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof. R is an alkyl group, and (n is in the range of 6 to 1300, preferably 6 to 100, and more preferably 6 to 9.) The method according to any one of claims 17 to 22, comprising one reactive terminal functional group and one non-reactive terminal functional group.

24. The polymer precursor compound is given by the following formula: 【Chemistry 2】 (In the formula, TG is a reactive terminal functional group selected from the group consisting of alkoxysilanes, alkoxyaluminums, alkoxyzirconiums, and combinations thereof; R is an alkyl group, and (n is in the range of 6 to 13000.) The method according to any one of claims 17 to 23, comprising two reactive terminal functional groups.

25. The method according to any one of claims 17 to 24, comprising a combination of two or more polymer compounds; wherein at least one polymer comprises one reactive terminal functional group and one non-reactive terminal functional group, preferably the polymer according to claim 23, and at least one polymer comprises two reactive terminal functional groups, preferably the polymer according to claim 24.

Images