Solid-state electrolyte composite comprising a solid-state polymer electrolyte, electrochemical device, and preparation method thereof

Abstract

The present invention relates to a solid-state electrolyte composite that includes a solid-state polymer electrolyte, a dissolved alkali metal salt and / or a dispersed alkali super ionic conductor, and optionally reinforcement additives. In other embodiments, the solid-state electrolyte composite includes a reinforcement interlayer. The solid-state polymer electrolyte comprises a polycarbonate crosslinked with cross-linkable moieties, selected from at least one from the group consisting of an acrylate group or a carbonate group. This composite is particularly suited for use in electrochemical devices, including half-electrode cells, full-electrode cells, all solid-state batteries, and supercapacitors, providing mechanical stability, better safety, and fast charge features. The invention further extends to an electrochemical device featuring this solid-state polymer composite and a method for preparing the solid-state electrolyte composite by mixing monomer precursors with a polymerization initiator, followed by polymerization and contacting the mixture with at least one electrode.

Description

SOLID-STATE ELECTROLYTE COMPOSITE COMPRISING A SOLID-STATE POLYMER ELECTROLYTE, ELECTROCHEMICAL DEVICE, AND PREPARATION METHOD THEREOFTechnical Domain

[0001] The present invention relates to the field of electrochemical energy storage and conversion devices, specifically to solid-state electrolyte composites suitable for use in such devices. The invention encompasses a solid-state polymer electrolyte composite that comprises a polycarbonate crosslinked with cross-linkable moieties, selected from at least one from the group consisting of an acrylate group or a carbonate group; and wherein the polymer electrolyte matrix comprises at least one from the group consisting of a dissolved alkali metal salt and / or a dispersed alkali super ionic conductor. Optionally, the composite also contains at least one additive to enhance structural, flame-retardancy, ionic conductive, or thermal properties. The electrolyte composite is particularly suitable for various types of electrochemical devices including half-electrode cells, full-electrode cells, all solid-state batteries, and supercapacitors, providing mechanical stability, better safety, and fast charge features. The invention further extends to methods of preparing such solid-state electrolyte composite, including steps for mixing monomer precursors with crosslinking agents and polymerization initiators, followed by in situ polymerization in contact with at least one electrode.Prior Art

[0002] The mobility landscape is undergoing profound transformations to meet the ambitious goals of the Paris Climate Change Agreement, in which Europe committed to achieve climate neutrality by 2050. Central to this revolution is the electrification of this sector, and the emergence of electrical vehicles (EVs). In this context, breakthroughs in cutting-edge technologies and innovative advanced materials have been boosted for shaping the future of mobile battery energy storage systems (BESS).

[0003] Traditional ion batteries utilize flammable liquid electrolytes composed of carbonate solvents, dissociable salts, and additives. This combination presents significant safety risks when the temperature exceeds 45 °C, compromising their thermal stability which is a critical factor for reliable operations.

[0004] A solid electrolyte is a material that should exhibit ionic conductivity similar to liquid counterparts but exists in a solid state, enabling it to conduct ions without the need for a liquid medium. Solid electrolytes are crucial components in various electrochemical devices, such as batteries and fuel cells, providing enhanced safety and thermal stability compared to traditional liquid electrolytes, and restricting the formation of parasitic reactions (e.g., dendrites formation). Particularly, solid polymer electrolytes are a group of solid electrolytes that show both fair mechanical strength and flexibility, as well as easy processing scalability.

[0005] There are two types of polymer electrolytes: solid polymer electrolytes (SPEs) and gel polymer electrolytes (GPEs). SPEs are less flammable and maintain stability at higher temperatures, significantly improving battery safety and lifespan, preventing issues like dendrite growth, while providing enhanced structural integrity.

[0006] In contrast, GPEs often contain flammable liquid components or expensive ionic liquids, posing safety risks akin to traditional liquid electrolytes or resulting in higher costs. They also exhibit lower thermal stability when compared to SPEs, potentially compromising battery performance and operational safety at elevated temperatures.

[0007] Despite SPEs facing challenges, including lower ionic conductivity at room temperature (10-8to 10-6S.cm-1) and a narrow potential range (< 4V), their advantages in safety and structural integrity establish them as the preferred choice for the next-generation battery technologies. This shift to all-solid-state polymer electrolytes marks a crucial advancement in enhancing the safety and efficiency of Battery Energy Storage Systems.Problems of the Prior Art

[0008] Up to date, significant efforts in addressing the ionic conductivity and electrochemical stability window of solid polymer electrolytes have been made. However, current advancements have not resulted in a substantial improvement. This remains the recognized limitations of solid polymer electrolytes that are highlighted in the scientific and technology communities.

[0009] International patent application WO2020143259A1 describes a polycarbonate-based polymer electrolyte applied in lithium-ion batteries. This electrolyte is prepared using vinyl ethylene carbonate, a conductive lithium salt, a porous support material, and a solvent. This process has limitations regarding the use of solvents, which results in the necessity of developing solvent recovery steps to mitigate environmental impact, although it results in additional costs. Moreover, the obtained solid-state electrolytes provide lower discharge rates of up to 0.1 C.

[0010] Qingjie Zhouet al. disclose a dual-salt gel polymer electrolyte, which is prepared via in situ polymerization of vinyl ethylene carbonate and pentaerythritol tetra acrylate monomers in a poly (vinylidene fluoride-co-hexafluoropropylene) porous structure. The dual-salt gel polymer electrolyte provides a limited C rate cycling with a capacity of 145 mAh / g over 100 cycles, and it does not reach maximum capacity for a cathode material (LiCoO2theoretical capacity = 274 mAh / g). Moreover, this electrolyte provides only 100 cycles with 17% fading capacity, resulting in a limited capacity retention of 83 %.

[0011] Lingfei Tanget al. disclose a polyfluorinated crosslinker to enhance oxidation resistance of solid polymer electrolytes, but scaling up the manufacturing of solid polymer electrolytes involves overcoming numerous technical challenges, particularly related to the high cost of precursors aiming at achieving cost-efficient industrial-scale production. The process disclosed in this prior art document has a further disadvantage, referring to the unavailability of results for long-term cycling superior to 0.5 C. Typical laboratory manufacturing practices often cannot be directly translated to an industrial scale.

[0012] Furthermore, the European Union is actively working to eliminate fluorinated compounds, particularly per- and polyfluoroalkyl substances (PFAS), due to their persistence in the environment and potential health risks.Solution of the Prior Art Problems

[0013] The present invention is directed to a crosslinked polycarbonate-based composite solid polymer electrolyte and its application in electrochemical devices, including half-electrode cells, full-electrode cells, all solid-state batteries, and supercapacitors, wherein the solid-state electrolyte in contact with one-electrode cell, or between a full-cell, or an association of cells that can perform from bellow to above room temperature.

[0014] Preferably, the present invention is directed to a new high-safety polymer-based composite electrolyte, which is characterized by a combination of a cross-linked polymer based on a polyvinyl ethylene carbonate, which is cross-linked by bonding cross-linkable moieties and with the addition of a conductive ion-based salt, namely a dissolved alkali metal salt and / or a dispersed alkali super ionic conductor or a mixture thereof. Preferably, the solid-state electrolyte composite according to the present invention comprises at least one additive, e.g. acting as a reinforcement.

[0015] The solid-state electrolyte composite according to the present invention also delivers consistent energy output and high performance, whether under low-rate discharges, ideal for long-duration applications, or high-rate discharges, suitable for high-power demands.Advantageous Effects of Invention

[0016] The solid-state electrolyte composite according to the present invention provides a way to improve the mechanical stability of the resulting polymer-based electrolytes, leading to better performance and longevity of the electrochemical cells, namely by providing better safety, fair mechanical performance, and fast charge features for the electrochemical cells. Moreover, the solid-state electrolyte composite has improved thermal stability related to higher operational safety and longevity.

[0017] As a further technical effect, the C-rate capacity and the capacity retention of the solid-state electrolyte composite according to the present invention are superior to the results provided by the prior art options known for a person skilled in the art.

[0018] With the purpose of providing an understanding of the principles according to the embodiments of the present invention, reference will be made to the embodiments illustrated in the drawings and to the terminology used to describe them. In any case, it should be understood that there is no intention of limiting the scope of the present invention to the contents of the figures. Any subsequent alterations or modifications of the inventive characteristics illustrated herein, as well as any additional applications of the principles and embodiments of the invention illustrated, which would normally occur to a person skilled in the art having the knowledge of this specification, are considered as being within the scope of the claimed invention.Fig.1

[0019] illustrates a graph showing the discharge capacity of a half-cell at different C rates;Fig.2

[0020] illustrates a graph with the first 150 cycles of a half-cell at 1C rate;Fig.3

[0021] illustrates an embodiment of a cross-sectional diagram of a two-electrode electrochemical cell two-electrode cell;Fig.4

[0022] illustrates an embodiment of three two-electrode cells set as if they were connected in series or parallel;Fig.5

[0023] illustrates an embodiment of a multilayer cell with alternate layers of electrolyte material and electrodes;Fig.6

[0024] illustrates the mechanical performance of the solid-state polymer composite electrolyte;Fig.7

[0025] illustrates the thermal stability of the solid-state polymer composite electrolyte;Fig.8

[0026] illustrates a schematic representation of a reinforcement layer in-between polymer matrix.Description of the Embodiments

[0027] The present invention refers, in a first aspect, to a solid-state electrolyte composite comprising a solid-state polymer electrolyte, a reinforcement material, and optionally at least one additive, wherein the solid-state polymer electrolyte comprises:

[0028] a polycarbonate comprising a polymer backbone crosslinked with cross-linkable moieties; and wherein the cross-linkable moieties are bonded to the polymer backbone and comprise functional groups, which are selected from at least one from the group consisting of an acrylate group or a carbonate group; and wherein

[0029] at least one from the group consisting of a dissolved alkali metal salt or a dispersed alkali super ionic conductor.

[0030] The monomers precursors of the polycarbonate are polymerized in the presence of compounds comprising cross-linkable moieties, wherein the outcomes of the polymerization reactions are the bonding of the cross-linkable moieties to the polymer backbone and the crosslinking of the polymer backbones by said cross-linkable moieties. Furthermore, before polymerization, the alkali metal salt and / or the alkali super ionic conductor is added to the pre-polymer mixture, and after the polymerization, the alkali metal salt is dissolved in the polymer matrix and / or the alkali super ionic conductor is dispersed in the polymer matrix.

[0031] In the preferred embodiments of the present invention, the polycarbonate is the polyvinyl ethylene carbonate.

[0032] In other particularly preferred embodiments, the source of the cross-linkable moiety is at least one compound selected from the group consisting of pentaerythritol tetraacrylate, bisphenol-A-ethoxylate dimethacrylate, N,N′-methylenebis(acrylamide), 2,2-Bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane, trimethylolpropane-ethoxylate triacrylate, polyethylene glycol dimetacrylate, and derivatives thereof.

[0033] Preferably, the dissolved alkali metal salt is at least one from the group consisting of RPF6, RClO4, RTFSI, RBOB, [RC(SO2CF3)3], and RFSI, wherein R is Li or Na.

[0034] Preferably, the dispersed alkali super ionic conductor is at least one from the group consisting of a NASICON-type material or a ferroelectric compound with the formula A3-2xMxClO; wherein A is selected from the group consisting of Li, Na or K; and M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5. More preferably, the alkali super ionic conductor is at least one from the group consisting of Na3Zr2Si2PO12, Na3.4Sc0.4Zr1.6Si2PO12, Na3.3Zr1.7La0.3Si2PO12, Na3.4Zr1.9Zn0.1Si2.2P0.8O12, Na3PS4, Na2.93PS3.93Cl0.06, Na3SbS4, Na3PSe4, Na11Sn2PS12, or Na2.99Ba0.005ClO.

[0035] Preferably, the dispersed alkali super ionic conductor is at least one from the group consisting of a LISICON-type material or a ferroelectric compound with the formula A3-2xMxClO; wherein A is selected from the group consisting of Li, Na or K; and M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5. More preferably, the dispersed alkali super ionic conductor is at least one from the group consisting of Li5Al0.5Ge1.5P3O12, Li1.5Al0.5Ge1.5(PO4)3, Li14Zn(GeO4)4), Li3PO4, Li7P3S11, Li2S-P2S5, Li2.99Ba0.005ClO,Lithium Lanthanum Zirconium Oxide, Lithium Lanthanum Zirconium Tantalum Oxide, Titanium Aluminum Lithium Phosphate, perovskite type Lithium Lanthanum Titanium oxide, and their analogues.

[0036] The dissolved alkali metal salt and / or the dispersed alkali super ionic conductor within the polymer matrix, provide ionic conductivity to the matrix, as well as decreasing the crystallinity of the matrix. These dissolved and / or dispersed conductors are not chemically linked to the polymer matrix.

[0037] In the preferred embodiments according to the invention, the weight of cross-linkable moieties in a pre-polymer mixture comprising cross-linkable moieties is in the range from 2% to 60% by weight of the pre-polymer mixture comprising cross-linkable moieties, considering the total weight of the carbonate and / or acrylate monomer’s precursor mixture as 100%.

[0038] Preferably, the weight of the dissolved alkali metal salt and / or the dispersed alkali super ionic conductor is in the range from 15% to 60% by weight of the solid-state polymer electrolyte.

[0039] In the preferred embodiments, the solid-state polymer composite comprises at least one additive selected, for example, a reinforcement additive, a flame-retardant additive, an ionic conductor additive, or a thermal stabilizer additive.

[0040] The additive can be selected among the group including an inorganic filler, a fiber, a polymer, cellulose, a polymer film, a fabric, or mixtures thereof. As it is understood by a person skilled in the art, an additive may provide more than one functional action. As an example, fillers can also act as flame retardants, and ion conductors, besides improving the thermal stability of the solid-state polymer electrolyte.

[0041] In the preferred embodiments of the solid-state polymer composite, the reinforcement additive comprises at least one from the group consisting of a filler or fiber. The fillers can act as reinforcements at the microscale, and the fibers act as reinforcements at the macroscale. Even preferably, the filler comprises at least one of the group including zinc oxide, magnesium carbonate, clays, or graphene oxide, and the fiber comprises at least one of the group including a glass fiber or a polymer fiber.

[0042] In other preferred embodiments, as illustrated in, a reinforcement interlayer is embedded within or integrated as a separate layer in the electrolyte structure. The reinforcement interlayer provides mechanical strength, flexibility, and stability to prevent cracking or deformation during use, ensuring the electrolyte maintains consistent ionic conductivity. Positioned either throughout the composite or at a specific interface, the reinforcement layer acts as a scaffold to support the electrolyte matrix comprising the polymer matrix, improving its thermal and chemical stability while preserving ion transport pathways.

[0043] The reinforcement interlayer includes one or more of plain weave glass fiber fabric, polytetrafluoroethylene (PTFE) non-woven fabric, or a polymer film. Preferably, the polymer film is based on fluoro-based polymers, a polyacrylonitrile (PAN) film, polyethylene oxide (PEO), cellulose, polyvinyl alcohols (PVA), polyvinyl acetate (PVAc) or a polymer of the polyaryletherketone (PAEK) family.

[0044] In the preferred embodiments of the present invention, the filler is an inorganic filler. Inorganic fillers can be added to the polymer matrix to improve its ionic conductivity, mechanical strength, flame retardancy, or thermal stability.

[0045] The inorganic filler is selected from at least one of the group consisting of a carbon-based nanomaterial, silica, titanium dioxide, alumina, barium titanate or zinc oxide.

[0046] Alternatively; when the solid-state polymer is for a sodium-based ion cell, the inorganic filler is selected from at least one of the group consisting of a NASICON-type material selected from the group consisting of Na3Zr2Si2PO12, Na3.4Sc0.4Zr1.6Si2PO12, Na3.3Zr1.7La0.3Si2PO12, Na3.4Zr1.9Zn0.1Si2.2P0.8O12, a sulfide-type material selected from the group consisting of cubic Na3PS4, Na2.93PS3.93Cl0.06, Na3SbS4, Na3PSe4, Na11Sn2PS12; a ferroelectric compound with the formula Na3-2xMxClO; wherein M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5.

[0047] Alternatively; when the solid-state polymer is for a lithium-based ion cell, the inorganic filler is selected from at least one of the group consisting of a LISICON-type material selected from the group consisting of Li5Al0.5Ge1.5P3O12, Li1.5Al0.5Ge1.5(PO4)3, Li14Zn(GeO4)4); Li3PO4, a sulfide-type material selected from the group consisting of Li7P3S11, Li2S-P2S5, a ferroelectric compound with the formula Li3-2xMxClO; wherein M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5, or a cubic Garnet type material selected from the group consisting of Lithium Lanthanum Zirconium Oxide, Lithium Lanthanum Zirconium Tantalum Oxide, Titanium Aluminum Lithium Phosphate, perovskite type Lithium Lanthanum Titanium Oxide, and their analogues.

[0048] Therefore, the NASICON-type material, the LISICON-type material, and said ferroelectric compound with the formula A3-2xMxClO, wherein A is selected from the group consisting of Li, Na or K; and M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5, can act as a dispersed alkali super ionic conductor, and as a reinforcement.

[0049] The solid-state polymer composite exhibits ionic conductivities of over 1x10-4S / cm from below to above room temperature (from 15 ºC to 40 ºC, e.g. 25 ºC), and a wide electrochemical stability window of up to 4.8V at room temperature. Moreover, it is thermally stable from -65°C to 110 °C, as illustrated byFinally, the solid-state polymer electrolyte shows low interfacial resistance, and good compatibility with both lithium and sodium metal as an anode material, other anode materials, and cathode materials, while showing fair mechanical strength with a storage modulus (E’) higher than 1.44 MPa, at room temperature, as illustrated by(b).

[0050] Graph 6 (a) represents the variation of Loss Modulus (E'') and Storage Modulus (E') as a function of temperature, highlighting the material's viscoelastic properties. While E'' is a measure of the energy dissipated as heat per deformation cycle, E' allows to assess the load-baring capacity of the matrix. Two well-defined relaxation modes can be observed, the first centered at -80°C and the second near -50°C, corresponding to the Brownian motion of the molecular chains at transition from the glassy to the rubbery state, corresponding to the glass transition (Tg) dynamics. Beyond Tg, E' stabilizes at a lower value, indicating a rubbery plateau, while E'' decreases as energy dissipation reduces.

[0051] From the graph, we can estimate the values of the Loss Modulus (E'') and Storage Modulus (E') at 30°C: a) Storage Modulus (E'): Around 100 MPa (as seen on the right y-axis); b) Loss Modulus (E''): Close to 0 MPa (as seen on the left y-axis).

[0052] At this temperature (working temperature of the electrolyte / battery cell), the material is in its rubbery state, where E' stabilizes at a lower value and E'' is minimal, indicating low energy dissipation. This data is essential for understanding temperature-dependent mechanical properties, crucial for applications requiring predictable performance across temperature ranges.

[0053] The crosslinking of moieties within these polymers presents another relevant aspect previously considered in attempts to refine electrolyte properties. Crosslinked polymers can offer improved dimensional stability and potentially better mechanical integrity compared to their non-crosslinked counterparts. Nevertheless, difficulties arise in maintaining high ionic conductivities due to the restricted mobility within highly crosslinked structures.

[0054] The optimal proportioning of cross-linkable moieties and conductive dissolved alkali metal salts or dispersed alkali super ionic conductors within pre-polymer mixtures further compounds development complexity; this requires careful calibration since an imbalance can lead either to reduced ionic performance or compromised mechanical attributes.

[0055] The present invention refers, in a second aspect, to an electrochemical device comprising a solid-state polymer composite according to the first aspect of the invention, wherein the electrochemical device is selected from the group consisting of a half-electrode cell, a full-electrode cell, a solid-state battery, or a supercapacitor, more preferably a lithium or sodium based electrochemical device.

[0056] The half-electrode cell comprises a single electrode, a reference electrode, a counter electrode, and the solid-state polymer composite.

[0057] The supercapacitor comprises a layered configuration with the solid-state polymer composite, as defined in the first aspect of the invention, arranged between two electrodes. Preferably, the electrochemical device comprises a plurality of full-electrode cells, and said full-electrode cells are configured to be connected in series or in parallel.

[0058] In other embodiments, the electrochemical device comprises a plurality of full-electrode cells, and said full-electrode cells are arranged as stacked cells.

[0059] The full-electrode cell or the solid-state battery comprises a positive electrode, a negative electrode, and the solid-state polymer composite.

[0060] For a polymer ion full-electrode cell the positive electrode includes a positive active material, a conductive agent, and a binder. The cathode active material may be selected from one or more of iron phosphate (RFePO4), lithium or sodium nickel manganese cobalt oxide (NMC), carbon, such as non-graphitized carbon and graphitized carbon, lithium or sodium cobalt oxide (RCoO2), and lithium or sodium manganese oxide (RMn2O4), wherein R is Li or Na.

[0061] For a polymer ion full-electrode cell, the negative active material of the negative electrode may be a conventional negative electrode material of a lithium-metal battery, or a material of a lithium-ion battery, and the example is not particularly limited. As a representative example of the negative electrode active material that can be used, it can be selected from lithium or sodium titanate (RTO); niobium titanium oxide (NTO), carbon, such as non-graphitized carbon and graphitized carbon; lithium or sodium metal; a lithium or sodium alloy; a silicon-based alloy; and analogs thereof, wherein R is Li or Na.

[0062] The present invention refers, in a third aspect, to a method of preparing a solid-state electrolyte composite comprising a solid-state polymer electrolyte, as defined in the first aspect of the invention, comprising the following steps:

[0063] a) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties; and

[0064] b) Dissolving an alkali metal salt and / or dispersing an alkali super ionic conductor in the mixture obtained in the previous step; and

[0065] c) adding a polymerization initiator to the mixture obtained in the previous step to carry out the polymerization to obtain the solid-state polymer electrolyte composite.

[0066] The present invention also comprises a method of preparing an electrochemical device, as defined in the second aspect of the invention, comprising a step of contacting the solid-state polymer electrolyte composite, obtained according to the method as defined in the second aspect of the invention, with at least one electrode to obtain the electrochemical device, namely a half-electrode cell.

[0067] Preferably, in steps a), b), or c) of the method according to the third aspect of the invention, at least one additive, for example, a reinforcement additive is added to the respective mixtures. More preferably, at least one additive is added to the homogeneous pre-polymer mixture comprising the respective monomers or the dissociable alkali metal salts and / or an alkali super ionic conductors in steps a) or b). The outcome of the polymerization step is a flexible and all-solid-state polymer having a net structure formed by crosslinked moieties. In this embodiment of the method of preparing a solid-state electrolyte composite, anex-situpolymerization is carried out, and the resulting solid-state electrolyte composite comprising a solid-state polymer electrolyte, a reinforcement additive and optionally at least one further additive, preferably a film of said solid-state electrolyte composite, is used to prepare an electrochemical cell.

[0068] The present invention refers, in a fourth aspect, to a method of preparing a solid-state electrolyte composite comprising a solid-state polymer electrolyte, as defined in the first aspect of the invention, comprising the following steps:

[0069] a) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties; and

[0070] b) Dissolving an alkali metal salt and / or dispersing an alkali super ionic conductor in the mixture obtained in the previous step; and

[0071] c) contacting at least one electrode with the mixture obtained in the previous step in the presence of a polymerization initiator to carry out the polymerization to obtain the solid-state electrolyte composite.

[0072] The solid-state electrolyte composite obtained according to the method, as defined in the fourth aspect of the invention, is an electrochemical device itself, considering the incorporation of at least one electrode in the polymer matrix.

[0073] Preferably, in steps a), b), or c) of the method according to the fourth aspect of the invention, at least one additive, for example, a reinforcement additive is added to the respective mixtures. More preferably, at least one additive is added to the homogeneous pre-polymer mixture comprising the respective monomers or the dissociable alkali metal salts and / or an alkali super ionic conductor in step c) before adding the polymerization initiator to provide anin situpolymerization.

[0074] The reinforcement additives are selected to strengthen the polymeric matrix while ideally not impeding or even promoting ion transport within the electrolyte system.

[0075] It is a preferred feature of the method according to the invention to add the homogeneous pre-polymer mixture directly between two electrodes, to provide in-situ polymerization between a one-electrode cell, or a half-cell or a full-cell. The method of the invention provides, therefore, uniform distribution of the polymer electrolyte, enhances interfacial contact between the electrolyte and the electrodes, and allows the assembly of the cell in a simple one-step, potentially reducing production costs and time.

[0076] The polymerization initiators can be at least one of the group consisting of a catalyst, heat or electromagnetic radiation in the ultra-violet (UV) spectrum. The catalyst is preferably selected from the group consisting of azobisisobutyronitrile (AIBN), dibutyl tin dilaurate, bis(acetylpyruvate) dibutyltin, azobisisoheptanonitrile (ABVN), dimethyl azobisisobutyrate (AIBME), benzoyl peroxide (BPO), platinum water (Pt), benzophenone, 4-methylbenzophenone (MBP), methyl benzoylformate (MBF), and mixtures thereof. The weight of the catalyst is preferably in the range of 0.1 to 5 wt.% based on the total weight of the pre-polymer matrix.Examples

[0077] Hereinafter, the present invention will be further explained through examples.

[0078] Example 1 - Preparation of solid polymer-based composite electrolyte for ion battery.

[0079] According to one embodiment of the present invention, there is provided a method of manufacturing the solid polymer electrolyte compositeex-situ, without the use of solvents, by radical polymerization including the following steps:

[0080] i) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties, an alkali metal salt, and fillers;

[0081] ii) addition of a polymerization initiator and stirring of the mixture;

[0082] iii) application of the mixture obtained in the previous step into a mold containing a reinforcement additive, and applying heat for a temperature into a range of 60º to 120 °C, for 10 to 20 hours, to crosslink the cross-linkable moieties, to obtain a multi-component composite polymer electrolyte having a net structure.

[0083] Example 2 - Preparation of solid polymer electrolyte for ion battery byin situpolymerization.

[0084] According to another embodiment of the present invention, there is provided a method of manufacturing the solid polymer electrolyte, by in-situ polymerization including the following steps:

[0085] i) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties, an alkali metal salt, and fillers;

[0086] ii) addition of a polymerization initiator and stirring of the mixture;

[0087] iii) application of the mixture obtained in the previous step directly between a cathode material and an anode material, and subsequently heating and curing the mixture in a temperature in a range of 60 ºC to 120 °C, for 10 to 20 hours to obtain a multi-component cathode / composite polymer electrolyte / anode.

[0088] The preferred embodiments of the present invention are illustrated by way of further examples below and in Figures 1 to 7.

[0089] In an exemplary embodiment of an electrochemical device according to the present invention, it can be designed to operate efficiently under varying discharge rates, ranging from 0.05 C to 2 C, as depicted in, which illustrates the discharge performance of the device at different C-rates, showcasing its ability to maintain high efficiency of over 150 mAh / g and stability across a wide spectrum of current demands, at room temperature. The electrochemical device of the results inis configured as a half-cell, featuring a cathode material with a theoretical capacity of 156 mAh / g. This configuration allows the device to deliver consistent energy output and high performance, whether under low-rate discharges, ideal for long-duration applications, or high-rate discharges, suitable for high-power demands. The C-rate is defined as the charge / discharge current divided by the nominally rated battery capacity.

[0090] In an exemplary embodiment of an electrochemical device according to the present invention, the superior cycling performance is depicted in, which illustrates that the cell maintains a capacity of over 150 mAh / g over 150 cycles at a 1 C rate, with a coulombic efficiency approaching 100%. The high-capacity retention and near-perfect coulombic efficiency highlight the cell's stability and efficiency, making it particularly suitable for applications requiring long cycle life and reliable performance, such as electric vehicles, portable electronics, and power tools. The results ofwere obtained after evaluating the cycling performance of a lithium-metal half-cell with LiFePO4as cathode material, Li metal as anode, and PVEC80-PETEA20 solid electrolyte with glass fiber as reinforcement material, wherein the solid-state polymer electrolyte comprises 80% (w / w) of polyvinyl ethylene carbonate (PVEC) and 20% (w / w) of pentaerythritol tetraacrylate (PETEA) crosslinker.

[0091] depicts a half or a full-electrode electrochemical cell that comprises a cathode (2) and an anode (1), with a solid-state electrolyte composite (3) according to the invention, interposed in-between. The electrolyte forms a good interface between electrodes, providing good ion transport and reduced interface resistance in the cell. The electrochemical cell can be encapsulated to form a “coin cell” or “pouch cell”. Electrochemical cells can be stacked into batteries.

[0092] In an exemplary embodiment depicted in, the present invention discloses an advanced electrochemical device comprising three half or full-electrode cells. These cells can be configured for either series or parallel connection, allowing for versatile adaptation to specific application requirements. In a series configuration, the cells are connected sequentially, resulting in an increased overall voltage, which is the sum of the individual cell voltages. Alternatively, in a parallel configuration, the cells are connected such that all positive terminals are linked together, and all negative terminals are linked together, thereby maintaining the same voltage as a single cell but enhancing the overall capacity.

[0093] depicts an exemplary embodiment of the present invention relating to a stacked electrochemical device with a configuration designed to enhance voltage output and overall energy density. This stacked device comprises a plurality of individual electrochemical cells arranged in a series connection within a single package. Each cell consists of a positive electrode (5), a solid-state electrolyte composite (3) according to the invention, and a negative electrode (4). Specifically, the positive electrode (5) of one cell is electrically connected to the negative electrode (4) of the adjacent cell, thereby forming a continuous series circuit. The solid-state electrolyte composite (3) within each cell is formulated to facilitate efficient ion transport between the electrodes, ensuring consistent performance and longevity. This series arrangement effectively sums the voltage of each individual cell, resulting in a higher overall output voltage while maintaining a compact form factor.

[0094] As used in this specification, the term “solid-state electrolyte composite” refers to a material used in electrochemical devices that conducts ions but remains in a solid-state.

[0095] As used in this specification, the term "cross-linkable monomer" is a monomer that can form covalent bonds with other monomers to create a three-dimensional network.

[0096] As used in this specification, the term "crosslinking agent" refers to a substance that facilitates the formation of covalent bonds between polymer chains, resulting in a crosslinked polymer network.

[0097] As used in this specification, the term "additive" is a substance added to the solid-state polymer composite to impart specific properties.

[0098] As used in this specification, the term "reinforcement additive" refers to substances added to the polymer electrolyte to enhance its mechanical properties at different scales, namely at microscale or at macroscale.

[0099] As used in this specification, the term "electrochemical device" refers to a device that generates electrical energy through electrochemical reactions. Broadly, this includes devices like half-electrode cells, full-electrode cells, solid state batteries, and supercapacitors.

[0100] As used throughout this description, the expressions “around” and “approximately” refer to a value range of more or less 10% the specified number.

[0101] As used throughout this patent application, the expression "or" is used in the inclusive sense instead of the exclusive sense, unless the exclusive sense is clearly defined in a specific situation. In this context, a sentence of the type "X uses A or B" must be interpreted as including all the pertinent inclusive combinations, for example "X uses A", "X uses B" and "X uses A and B".

[0102] As used throughout this patent application, the indefinite article "one" must be interpreted generally as "one or more", unless the sense of a singular embodiment is clearly defined in a specific situation.

[0103] As presented in this specification, the expressions related to examples must be interpreted with the purpose of illustrating an example and not indicating a preference.

[0104] As used in this specification, the expression "substantially" means that the real value is within the range of values of about 10% the desired value, variable, or related threshold, particularly within about 5% of the desired value, variable, or related threshold or particularly within about 1% of the desired value, variable, or related threshold.

[0105] The subject matter described above is provided as an illustration of the present invention and must not be interpreted so as to limit it. The terminology used with the purpose of describing specific embodiments, according to the present invention, must not be interpreted to limit the invention. As used in the specification, the definite and indefinite articles, in their singular form, aim at the interpretation of also including the plural forms, unless the context of the description indicates, explicitly, the contrary. It will be understood that the expressions “comprise” and “include”, when used in this description, specify the presence of the characteristics, the elements, the components, the steps, and the related operations, however, they do not exclude the possibility of other characteristics, elements, components, steps, and operations also being contemplated.

[0106] All the alterations, providing that they do not modify the essential characteristics of the claims that follow, must be considered as being within the scope of protection of the present invention.List of Reference Indications

[0107] 1. An anode

[0108] 2. A cathode

[0109] 3. A solid-state electrolyte composite according to the invention

[0110] 4. A negative electrode

[0111] 5. A positive electrodeList of Citations

[0112] Patent documents

[0113] International patent application WO2020143259A1, entitled “Preparation and application of polycarbonate-based polymer electrolyte” of Yu Haijun et al., published on 2020-07-16.Non Patent Literature

[0114] Qingjie Zhou, Chuankai Fu, Renlong Li, Xueyan Zhang, Bingxing Xie, Yunzhi Gao, Geping Yin, Pengjian Zuo, Poly (vinyl ethylene carbonate)-based dual-salt gel polymer electrolyte enabling high voltage lithium metal batteries, Chemical Engineering Journal, Volume 437, Part 2, 2022.

[0115] Tang, L., Chen, B., Zhang, Z. et al. Polyfluorinated crosslinker-based solid polymer electrolytes for long-cycling 4.5 V lithium metal batteries. Nat Commun. 14, 2301 (2023).

Claims

A solid state electrolyte composite comprising a solid-state polymer electrolyte,characterizedin that the solid-state polymer electrolyte comprises:a polycarbonate comprising a polymer backbone crosslinked with cross-linkable moieties; and wherein the cross-linkable moieties are bonded to the polymer backbone and comprise functional groups, which are selected from at least one from the group consisting of an acrylate group or a carbonate group; andat least one from the group consisting of a dissolved alkali metal salt or a dispersed alkali super ionic conductor.The solid-state polymer composite, according to the preceding claim, wherein the polycarbonate is polyvinyl ethylene carbonate.The solid state polymer composite, according to any one of the preceding claims, wherein thecross-linkable moiety is at least one from the group consisting of pentaerythritol tetraacrylate, bisphenol-A-ethoxylate dimethacrylate, N,N′-methylenebis(acrylamide), 2,2-Bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane, trimethylolpropane-ethoxylate triacrylate, polyethylene glycol dimetacrylate, and derivatives thereof.The solid-state polymer composite, according to any one of the preceding claims, wherein the dissolved alkali metal salt is at least one from the group consisting of RPF6, RClO4, RTFSI, RBOB, [RC(SO2CF3)3], RFSI, wherein R is Li or Na.The solid-state polymer composite, according to any one of the preceding claims, wherein the dispersed alkali super ionic conductor is at least one from the group consisting of a NASICON-type material, a LISICON-type material or a ferroelectric compound with the formula A3-2xMxClO; wherein A is selected from the group consisting of Li, Na or K; and M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5.The solid-state polymer composite, according to the preceding claim, wherein the dispersed alkali super ionic conductor is at least one from the group consisting of Na3Zr2Si2PO12, Na3.4Sc0.4Zr1.6Si2PO12, Na3.3Zr1.7La0.3Si2PO12, Na3.4Zr1.9Zn0.1Si2.2P0.8O12, Na3PS4, Na2.93PS3.93Cl0.06, Na3SbS4, Na3PSe4, Na11Sn2PS12, or Na2.99Ba0.005ClO; orthe dispersed alkali super ionic conductor is at least one from the group consisting of Li5Al0.5Ge1.5P3O12, Li1.5Al0.5Ge1.5(PO4)3, Li14Zn(GeO4)4), Li2.99Ba0.005ClO, Li3PO4, Li7P3S11, Li2S-P2S5,Lithium Lanthanum Zirconium Oxide, Lithium Lanthanum Zirconium Tantalum Oxide, Titanium Aluminum Lithium Phosphate, perovskite type Lithium Lanthanum Titanium Oxide, and their analogues.The solid-state polymer composite, according to any one of the preceding claims, wherein the weight of cross-linkable moieties in a pre-polymer mixture comprising cross-linkable moieties is in the range from 2% to 60% by weight of the pre-polymer mixture comprising cross-linkable moieties.The solid-state polymer composite, according to any one of the preceding claims, wherein the weight of the dissolved alkali metal salt and / or the dispersed alkali super ionic conductor is in the range from 15% to 60% by weight of the solid-state polymer electrolyte.The solid-state polymer composite, according to any one of the preceding claims, wherein the solid-state polymer composite comprises at least one additive selected from the group consisting of a reinforcement additive, a flame-retardant additive, an ionic conductor additive, or a thermal stabilizer additive.The solid-state polymer composite, according to the preceding claim, wherein the additive is selected from the group consisting of an inorganic filler, a fiber, a polymer, cellulose, a polymer film, or a fabric.The solid-state polymer composite, according to the preceding claim, wherein the inorganic filler is selected from at least one of the group consisting of a carbon-based nanomaterial, silica, titanium dioxide, alumina, barium titanate or zinc oxide; orwhen the solid-state polymer is for a sodium-based ion cell, the inorganic filler is selected from at least one of the group consisting of a NASICON-type material selected from the group consisting of Na3Zr2Si2PO12, Na3.4Sc0.4Zr1.6Si2PO12, Na3.3Zr1.7La0.3Si2PO12, Na3.4Zr1.9Zn0.1Si2.2P0.8O12, a sulfide-type material selected from the group consisting of cubic Na3PS4, Na2.93PS3.93Cl0.06, Na3SbS4, Na3PSe4, Na11Sn2PS12, or a ferroelectric compound with the formula Na3-2xMxClO; wherein M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5; orwhen the solid-state polymer is for a lithium-based ion cell, the inorganic filler is selected from at least one of the group consisting of a LISICON-type material selected from the group consisting of Li5Al0.5Ge1.5P3O12, Li1.5Al0.5Ge1.5(PO4)3, Li14Zn(GeO4)4), Li3PO4, or a sulfide-type material selected from the group consisting of Li7P3S11, Li2S-P2S5, a ferroelectric compound with the formula Li3-2xMxClO; wherein M is selected from the group consisting of Mg, Ca, Sr or Ba; and x is an integer in the range from 0 to 0.5, or a cubic Garnet type material selected from the group consisting of Lithium Lanthanum Zirconium Oxide, Lithium Lanthanum Zirconium Tantalum Oxide, Titanium Aluminum Lithium Phosphate, perovskite type Lithium Lanthanum Titanium Oxide, and their analogues.An electrochemical devicecharacterizedby comprising a solid-state polymer composite as defined in any one of the preceding claims.The electrochemical device, according to the preceding claim, wherein the electrochemical device is selected from the group consisting of a half-electrode cell, a full-electrode cell, a solid-state battery, or a supercapacitor.The electrochemical device, according to claim 13, wherein the half-electrode cell comprises a single electrode, a reference electrode, a counter electrode, and the solid-state polymer composite.The electrochemical device, according to claim 13, wherein the full-electrode cell or the solid-state battery comprises a positive electrode, a negative electrode, and wherein the solid-state polymer composite is disposed between said positive electrode and said negative electrode.The electrochemical device, according to claim 13, wherein the electrochemical device comprises a plurality of full-electrode cells, and said full-electrode cells are configured to be connected in series or in parallel.The electrochemical device, according to any one of claims 13 to 16, wherein the electrochemical device comprises a plurality of full-electrode cells, and said full-electrode cells are arranged as stacked cells.The electrochemical device, according to claim 13, wherein the supercapacitor comprises a layered configuration, and wherein the solid-state polymer composite is arranged between two electrodes.A method of preparing a solid-state electrolyte composite comprising a solid-state polymer electrolyte, as defined in any one of the claims 1 to 11, characterized by comprising the following steps:a) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties; andb) Dissolving an alkali metal salt and / or dispersing an alkali super ionic conductor in the mixture obtained in the previous step; andc) adding a polymerization initiator to the mixture obtained in the previous step to carry out the polymerization to obtain the solid-state polymer electrolyte composite.A method of preparing a solid-state electrolyte composite comprising a solid-state polymer electrolyte, as defined in any of the claims 1 to 11, characterized by comprising the following steps:a) Mixing monomers precursors of the polycarbonate with compounds comprising cross-linkable moieties; andb) Dissolving an alkali metal salt and / or dispersing an alkali super ionic conductor in the mixture obtained in the previous step; andc) contacting at least one electrode with the mixture obtained in the previous step in the presence of a polymerization initiator to carry out the polymerization to obtain the solid-state electrolyte composite.

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