LOW INTERFACIAL RESISTANCE ELECTROLYTE FILM

Abstract

Electrolyte layer (26) for use in an electrochemical cell (20) that circulates lithium ions, the electrolyte layer (26) comprising: a porous film defining a multitude of cavities and comprising a multitude of solid electrolyte particles (30) and a multitude of polymer fibrils (38) connecting the solid electrolyte particles (30); and a gel polymer electrolyte (28) that at least partially fills the multitude of cavities in the porous film, wherein the polymeric fibrils (38) are selected from the group consisting of: polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylene propylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, ethylenetetrafluoroethylene (ETFE) fibrils and combinations thereof, wherein each of the polymeric fibrils (38) has a fiber length of more than or equal to 2 micrometers to less than or equal to 100 micrometers and a molecular weight of more than or equal to 10 5 g / mol to less than or equal to 10 9 g / mol.

Description

INTRODUCTION

[0001] This section contains background information on the present disclosure that does not necessarily belong to the prior art.

[0002] Electrochemical energy storage devices, such as lithium-ion batteries, can be used in a wide variety of products, including automotive products such as start-stop systems (e.g., 12V start-stop systems), battery-assisted systems (µBAS), hybrid electric vehicles (HEVs), and electric vehicles (EVs). Typical lithium-ion batteries contain two electrodes and an electrolyte component and / or a separator. One of the two electrodes can serve as the positive electrode or cathode, and the other as the negative electrode or anode. Lithium-ion batteries may also contain various terminal and packaging materials. Rechargeable lithium-ion batteries function by reversibly transferring lithium ions back and forth between the negative and positive electrodes.For example, lithium ions can move from the positive electrode to the negative electrode when the battery is charged and in the opposite direction when the battery is discharged.

[0003] A separator and / or electrolyte can be placed between the negative and positive electrodes. The electrolyte is suitable for conducting lithium ions between the electrodes and, like the two electrodes, can be in solid, liquid, or a solid-liquid mixture. In solid-state batteries that contain a solid electrolyte layer between solid electrodes, the solid electrolyte physically separates the electrodes, eliminating the need for a separate separator. Solid electrolytes, such as oxide-based solid electrolyte layers, often have a greater thickness (e.g., 600 µm), which reduces the overall energy density of the battery. Such solid electrolytes are also often only suitable for use at low currents (e.g., 0.05 C rate) and relatively high temperatures (e.g., 60 °C).Therefore, it would be desirable to develop electrolyte layers with improved energy densities, conductivities, and mechanical properties.

[0004] Document US 2015 / 0 318 570 A1 discloses a polymer electrolyte comprising: a separator consisting of a first porous nanofiber network with a plurality of nanofibers, and a gel polymer component impregnated in the first porous nanofiber web.

[0005] German patent application DE 10 2021 114 604 A1 discloses a method for producing an electrochemical solid-state cell with one or more solid-state electrodes and a distributed solid-state electrolyte, wherein one or more sulfide solid-state electrolytes, halide-based solid-state electrolytes, or polymer-based solid-state electrolytes could be used as materials for the solid-state electrolyte. Furthermore, it is described that the separator can be a fibrous membrane and consists of, for example, polyimide (Pl) nanofibers.

[0006] Patent US 5,665,265 A discloses a polymer-gel electrolyte system with positive and negative electrodes comprising an electrolytically active species and a polymer support structure, which includes an inert and non-woven first polymer component (a fibrous material) and a gelling second polymer component. SUMMARY

[0007] This section contains a general summary of the revelation and does not constitute a comprehensive revelation of its full scope or all features.

[0008] The present invention is based on the objective of providing an improved electrolyte layer. This objective is achieved by the subject matter of independent claim 1. Advantageous embodiments of the present invention are described in the dependent claims.

[0009] The present disclosure relates to electrolyte layers for electrochemical cells that circulate lithium ions, as well as to methods for their production and use. The electrolyte layers include, for example, oxide-based solid electrolyte layers, including fibrillated polymers and a gel-polymer electrolyte.

[0010] In various aspects, the present disclosure provides an electrolyte layer for use in an electrochemical cell that circulates lithium ions. The electrolyte layer can comprise a porous film defining a plurality of cavities and containing a plurality of solid electrolyte particles and a plurality of polymer fibrils connecting the solid electrolyte particles. The electrolyte layer also comprises a gel-polymer electrolyte that can at least partially fill the plurality of cavities in the porous film.The polymeric fibrils (38) are selected from the group consisting of: polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylene propylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, ethylenetetrafluoroethylene (ET-FE) fibrils and combinations thereof, wherein each of the polymeric fibrils (38) has a fiber length of more than or equal to 2 micrometers to less than or equal to 100 micrometers and a molecular weight of more than or equal to 10. 5 g / mol to less than or equal to 10 9 g / mol.

[0011] In one aspect, the solid electrolyte particles can exhibit an ionic conductivity of more than or equal to 0.1 mS / cm to less than or equal to 20 mS / cm at temperatures greater than or equal to 20 °C to less than or equal to eta 22 °C. The variety of solid electrolyte particles can be selected from the following group: oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles, and combinations thereof.

[0012] In one aspect, the multitude of solid electrolyte particles can include oxide-based solid particles.

[0013] Regarding one aspect, polytetrafluoroethylene (PTFE) fibrils can have a softening point of more than or equal to 260 °C to less than or equal to 327 °C. Fluorinated ethylene propylene (FEP) fibrils can have a softening point of more than or equal to 204 °C to less than or equal to 260 °C. Ethylene tetrafluoroethylene (ETFE) fibrils can have a softening point of more than or equal to 260 °C to less than or equal to 315 °C.

[0014] In one aspect, the gel polymer electrolyte can contain more than or equal to 0.1 wt.% to less than or equal to 50 wt.% of a polymer host and more than or equal to 5 wt.% to less than or equal to 90 wt.% of a liquid electrolyte.

[0015] For one aspect, the polymer host can be selected from the group consisting of: polyethylene oxide (PEO), polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), polymethyl methacrylate (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP) and combinations thereof.

[0016] In one aspect, the porous film can have a porosity of more than or equal to 10 vol% to less than or equal to 50 vol%, and the gel polymer electrolyte can fill more than or equal to 60% to less than or equal to 100% of a total porosity defined by the plurality of cavities of the porous film.

[0017] In one aspect, the porous film can contain more than or equal to 70 wt% to less than or equal to 99 wt% of the plurality of solid electrolyte particles, more than or equal to 0.1 wt% to less than or equal to 10 wt% of the plurality of polymer fibrils, and more than or equal to 0.1 wt% to less than or equal to 20 wt% of the gel polymer electrolyte.

[0018] In one aspect, the electrolyte layer can have an average thickness of more than or equal to 2 micrometers to less than or equal to 100 micrometers.

[0019] Not according to the invention is an electrochemical cell that circulates lithium ions. The electrochemical cell can comprise a first electrode, a second electrode, and an electrolyte layer arranged between the first and second electrodes. The electrolyte layer can contain a plurality of solid electrolyte particles, a plurality of polymer fibrils connecting the solid electrolyte particles, and a gel-polymer electrolyte that at least partially fills the cavities formed between the solid electrolyte particles and the polymer fibrils.

[0020] In one aspect, the multitude of solid electrolyte particles can exhibit an ionic conductivity of more than or equal to approximately 0.1 mS / cm to less than or equal to approximately 20 mS / cm at temperatures greater than or equal to approximately 20 °C to less than or equal to approximately 22 °C. The multitude of solid electrolyte particles can be selected from the following group: oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles, and combinations thereof.

[0021] In one aspect, each of the polymer fibrils can have a fiber length of more than or equal to approximately 2 micrometers to less than or equal to approximately 100 micrometers and a molecular weight of more than or equal to approximately 10 5 g / mol to less than or equal to approximately 10 9g / mol. The polymer fibrils can be selected from the group consisting of: polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylenepropylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, ethylenetetrafluoroethylene (ETFE) fibrils and combinations thereof.

[0022] In one aspect, the gel polymer electrolyte can contain more than or equal to approximately 0.1 wt% to less than or equal to approximately 50 wt% of a polymer host and more than or equal to approximately 5 wt% to less than or equal to approximately 90 wt% of a liquid electrolyte.

[0023] In one aspect, the multitude of solid electrolyte particles and the multitude of polymer fibrils linking these particles can form a porous film defining a multitude of cavities. The porous film can have a porosity ranging from approximately 10% to approximately 50% by volume, and the gel polymer electrolyte can fill approximately 0.1% to approximately 150% of the multitude of cavities within the porous film.

[0024] In one aspect, the electrolyte layer can have a thickness of more than or equal to approximately 2 micrometers to less than or equal to approximately 100 micrometers.

[0025] Not according to the invention is an electrolyte layer for use in an electrochemical cell that circulates lithium ions. The electrolyte layer can comprise a porous film defined by a plurality of oxide-based solid particles and a plurality of polymer fibrils connecting the solid electrolyte particles. The porous film can have a thickness of more than or equal to about 2 micrometers to less than or equal to about 100 micrometers and a porosity of more than or equal to about 10% by volume to less than or equal to about 50% by volume. The electrolyte layer can further comprise a gel-polymer electrolyte that fills more than or equal to about 0.1% to less than or equal to about 150% of the total porosity of the porous film.

[0026] In one aspect, each of the polymer fibrils can have a fiber length of more than or equal to approximately 2 micrometers to less than or equal to approximately 100 micrometers. The polymer fibrils can be selected from the following group: polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylene propylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, ethylenetetrafluoroethylene (ETFE) fibrils, and combinations thereof.

[0027] In one aspect, the gel polymer electrolyte can contain more than or equal to approximately 0.1 wt% to less than or equal to approximately 50 wt% of a polymer host and more than or equal to approximately 5 wt% to less than or equal to approximately 90 wt% of a liquid electrolyte.

[0028] Further areas of application arise from the present description. The description and specific examples in this summary serve only for illustration and are not intended to limit the scope of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described here serve only to illustrate selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. Fig. Figure 1 is a representation of an exemplary electrochemical cell with an electrolyte layer containing a variety of solid electrolyte particles, fibrillated polymers and a gel polymer electrolyte according to various aspects of the present disclosure; Fig. Figure 2 is a flowchart showing an example of a process for forming an electrolyte layer according to various aspects of the present disclosure; Fig. Figure 3A is a graphical representation showing the impedance of an exemplary electrolyte layer according to various aspects of the present disclosure; Fig. Figure 3B is a graphical representation showing the capacity conservation of an exemplary electrolyte layer according to various aspects of the present disclosure; and Fig. 3C is a graphical representation that shows the surface conductivity (Ohm / cm²). 2 ) of an exemplary electrolyte layer according to various aspects of the present disclosure.

[0030] The corresponding reference symbols designate the relevant parts in the different views of the drawings. DETAILED DESCRIPTION

[0031] Examples of implementation will now be described in more detail with reference to the attached drawings.

[0032] Current technology concerns solid-state batteries (SSBs) and methods for their manufacture and use. Solid-state batteries can contain at least one solid component, such as at least one solid electrode, but also, in certain variants, semi-solid or gel, liquid, or gas components. In various cases, solid-state batteries can have a bipolar stack design comprising a plurality of bipolar electrodes, with a first mixture of electroactive solid material particles (and optional solid electrolyte particles) arranged on a first side of a current collector and a second mixture of electroactive solid material particles (and optional solid electrolyte particles) arranged on a second side of a current collector, parallel to the first side. The first mixture can contain cathode material particles as electroactive solid material particles.The second mixture can contain anode material particles as electroactive solid material particles. The solid electrolyte particles can be the same or different in each case.

[0033] In other variants, the solid-state batteries can have a monopolar stack design comprising a plurality of monopolar electrodes, wherein a first mixture of electroactive solid material particles (and optional solid electrolyte particles) is arranged on both a first and a second side of a first current collector, the first and second sides of the first current collector being essentially parallel, and a second mixture of electroactive solid material particles (and optional solid electrolyte particles) is arranged on both a first and a second side of a second current collector, the first and second sides of the second current collector being essentially parallel. The first mixture can contain cathode material particles as electroactive solid material particles. The second mixture can contain anode material particles as electroactive solid material particles.The solid electrolyte particles can be identical or different in any case. In certain variants, solid-state batteries can contain a mixture of bipolar and monopolar stacked configurations.

[0034] Such solid-state batteries can be incorporated into energy storage devices such as rechargeable lithium-ion batteries, which can be used in motor vehicles (e.g., motorcycles, boats, tractors, buses, motorhomes, caravans, and tanks). However, the current technology can also be used in other electrochemical devices, such as (but not limited to) components for aerospace, consumer goods, appliances, buildings (e.g., houses, offices, sheds, and warehouses), office equipment and furniture, as well as machinery for industrial equipment, agricultural equipment, farm machinery, or heavy machinery. In various aspects, the present disclosure provides a rechargeable lithium-ion battery that exhibits high temperature tolerance, improved safety, and superior performance and lifespan.

[0035] An exemplary and schematic representation of an electrochemical solid-state cell unit (also referred to as a “solid-state battery” and / or “battery”) 20, which circulates lithium ions, is shown in Fig. Figure 1 shows the battery 20 comprising a negative electrode (i.e., anode) 22, a positive electrode (i.e., cathode) 24, and an electrolyte layer 26 occupying a space defined between the two or more electrodes 22, 24. The electrolyte layer 26 is a solid or semi-solid separating layer that physically separates the negative electrode 22 from the positive electrode 24. As discussed below, the electrolyte layer 26 may comprise a flexible, porous film defined by a first plurality of solid electrolyte particles 30 and fibrillated polymers 38, as well as a (first) gel polymer electrolyte 28 that at least partially fills cavities or pores and grain boundaries in the porous film.

[0036] A second plurality of solid electrolyte particles 90 can be mixed with negative electroactive solid particles 50 in the negative electrode 22, and a third plurality of solid electrolyte particles 92 can be mixed with positive electroactive solid particles 60 in the positive electrode 24, which together with the first plurality of electrolyte layers 30 can form a continuous electrolyte network. Although not shown, in certain variants a (second) gel-polymer electrolyte can also be included in the negative electrode 22, which at least partially fills the cavities between the negative electroactive solid particles 50 and / or the optional second plurality of solid electrolyte particles 90.Similarly, a (third) gel-polymer electrolyte can be contained in the positive electrode 24, which at least partially fills the cavities between the positive electroactive solid particles 60 and / or the optional third plurality of solid electrolyte particles 92. The second gel-polymer electrolyte can be identical to or different from the third gel-polymer electrolyte. The second gel-polymer electrolyte and / or the third gel-polymer electrolyte can be identical to or different from the first gel-polymer electrolyte.

[0037] A first current collector 32 can be arranged at or near the negative electrode 22. The first current collector 32 can be a metal foil, a metal grid or mesh, or expanded metal containing copper or another suitable electrically conductive material known to those skilled in the art. A second current collector 34 can be arranged at or near the positive electrode 24. The second current collector 34 can consist of a metal foil, a metal grid or mesh, or expanded metal containing aluminum or another suitable electrically conductive material known to those skilled in the art. The first current collector 32 and the second current collector 34 can be identical or different. The first current collector 32 and the second electrode current collector 34 collect free electrons and transport them to and from an external circuit 40.For example, an interruptible external circuit 40 and a load device 42 can connect the negative electrode 22 (via the first current collector 32) and the positive electrode 24 (via the second current collector 34).

[0038] Although not shown, a person skilled in the art will recognize that in certain embodiments the first current collector 32 can be a first bipolar current collector and / or the second current collector 34 can be a second bipolar current collector. The first bipolar current collector 34 and / or the second bipolar current collector 34 can, for example, be plated foils, wherein one side (e.g., the first side or the second side) of the current collector 32, 34 contains a metal (e.g., a first metal) and another side (e.g., the other side of the first side or the second side) of the current collector 32 contains another metal (e.g., a second metal). In certain variants, the plated foils may contain, for example, only aluminium copper (Al-Cu), nickel copper (Ni-Cu), stainless copper (SS-Cu), aluminium nickel (Al-Ni), aluminium stainless steel (Al-SS) and nickel stainless steel (Ni-SS).In certain variants, the first bipolar pantograph 32 and / or the second bipolar pantograph 34 may be pre-coated, for example with graphene or carbon-coated aluminum pantographs.

[0039] Battery 20 can generate an electric current (in Fig. (1 marked by arrows) during discharge by reversible electrochemical reactions that occur when the external circuit 40 is closed (to connect the negative electrode 22 and the positive electrode 24) and when the negative electrode 22 has a lower potential than the positive electrode 24. The chemical potential difference between the negative electrode 22 and the positive electrode 24 drives electrons, generated by a reaction, e.g., the oxidation of intercalated lithium, at the negative electrode 22, through the external circuit 40 to the positive electrode 24. Lithium ions, also generated at the negative electrode 22, are simultaneously transferred through the electrolyte layer 26 to the positive electrode 24.The electrons flow through the external circuit 40 and the lithium ions migrate through the electrolyte layer 26 to the positive electrode 24, where they can be plated, reacted, or stored. The electric current flowing through the external circuit 40 can be used and passed through the load device 42 (in the direction of the arrow) until the lithium in the negative electrode 22 is consumed and the capacity of the battery 20 decreases.

[0040] Battery 20 can be recharged or re-energized at any time by connecting an external power source (e.g., a charger) to it to reverse the electrochemical reactions that occur during battery discharge. The external power source that can be used to recharge battery 20 depends on its size, design, and intended use. Notable examples of such external power sources include an AC-DC converter connected to an AC power supply via a wall socket and a motor vehicle alternator. Connecting the external power source to battery 20 promotes a reaction, such as the non-spontaneous oxidation of intercalated lithium, at the positive electrode 24, generating electrons and lithium ions.The electrons flowing back to the negative electrode 22 through the external circuit 40, and the lithium ions moving back to the negative electrode 22 through the electrolyte layer 26, recombine at the negative electrode 22 and replenish it with lithium, which is then consumed during the next battery discharge cycle. Thus, a complete discharge followed by a complete charge is considered a cycle in which lithium ions move back and forth between the positive electrode 24 and the negative electrode 22.

[0041] Although the illustrated example comprises a single positive electrode 24 and a single negative electrode 22, the person skilled in the art will recognize that the present teaching is applicable to various other configurations, including those with one or more cathodes and one or more anodes, as well as to various current collectors and current collector foils with electroactive particle layers arranged on, beside, or embedded in one or more of their surfaces. Likewise, it should be recognized that the battery 20 may contain a multitude of other components, which, although not shown here, are nevertheless known to the person skilled in the art.The battery 20 may, for example, contain a casing, a seal, terminal caps and other conventional components or materials that may be located inside the battery 20, including between or around the negative electrode 22, the positive electrode 24 and / or the electrolyte layer 26.

[0042] In many configurations, the first current collector 32, the negative electrode 22, the electrolyte layer 26, the positive electrode 24, and the second current collector 34 are each manufactured as relatively thin layers (e.g., with a thickness of a few micrometers to one millimeter or less) and assembled in layers connected in series to provide a suitable package of electrical energy, battery voltage, and power, e.g., to obtain a series-connected elementary cell core (SECC). In various other cases, the battery 20 may further include electrodes 22, 24 connected in parallel to provide a suitable electrical energy, battery voltage, and power, e.g., to obtain a parallel-connected elementary cell core (PECC).

[0043] The size and shape of the battery 20 can vary depending on the application for which it is designed. Battery-powered vehicles and handheld electronic devices are two examples where the battery 20 is most likely to be designed to different specifications regarding size, capacity, voltage, energy, and power output. The battery 20 can also be connected in series or parallel with other similar lithium-ion cells or batteries to produce a higher output voltage, energy, and power when required by the load device 42. The battery 20 can generate an electrical current for the load device 42, which can be connected to the external circuit 40. The load device 42 can be powered wholly or partially by the electrical current flowing through the external circuit 40 as the battery 20 is discharged.The load device 42 can be any number of known electrically powered devices. Some specific examples (not limited to) of power-consuming load devices are an electric motor for a hybrid or all-electric vehicle, a laptop computer, a tablet computer, a mobile phone, and cordless power tools or devices. The load device 42 can also be a power-generating device that charges the battery 20 for the purpose of storing electrical energy.

[0044] With renewed reference to Fig. 1. The electrolyte layer 26 provides electrical isolation between the negative electrode 22 and the positive electrode 24, thus preventing physical contact. The electrolyte layer 26 also offers a path of minimal resistance for the internal flow of lithium ions. In certain variants, the electrolyte layer 26 can be a freestanding membrane. That is, the electrolyte layer 26 can be self-supporting and structurally intact and can be treated as an independent layer (e.g., removed from a substrate) rather than as a coating on another component.

[0045] In various aspects, the electrolyte layer 26 can comprise a porous film defined by a first plurality of solid electrolyte particles 30 and fibrillated polymers 38. For example, the fibrillated polymers 38 can effectively connect or bond the solid electrolyte particles 30 together. The porous film can have a porosity of more than or equal to approximately 10 volume percent to less than or equal to approximately 50 volume percent, and in certain aspects optionally more than or equal to approximately 25 volume percent to less than or equal to approximately 40 volume percent. The electrolyte layer 26 further contains a (first) gel-polymer electrolyte 28, which at least partially fills the pores in the porous film. For example, the gel polymer electrolyte 28 can penetrate cavities and / or grain boundaries between the solid electrolyte particles 30 and help to form favorable ion transfer bridges at the solid interfaces.In certain variants, the gel polymer electrolyte 28 can fill more than or equal to approximately 60% to less than or equal to approximately 100% of the total porosity of the porous film.

[0046] In various aspects, the solid electrolyte particles 30 are selected to exhibit high ionic conductivity. For example, the solid electrolyte particles 30 can have an ionic conductivity of more than or equal to approximately 0.1 mS / cm to less than or equal to approximately 20 mS / cm, and in certain aspects optionally from more than or equal to approximately 0.1 mS / cm to less than or equal to approximately 5 mS / cm, at room temperature (i.e., more than or equal to approximately 20 °C to less than or equal to approximately 22 °C). In certain variants, the solid electrolyte particles 30 can have an average particle diameter of more than or equal to approximately 0.02 µm to less than or equal to approximately 20 µm, optionally more than or equal to approximately 0.1 µm to less than or equal to approximately 10 µm, and in certain aspects optionally more than or equal to approximately 0.1 µm to less than or equal to approximately 1 µm.

[0047] In certain variants, the solid electrolyte particles 30 can, for example, include oxide-based solid particles. These oxide-based solid particles can be garnet-type solid particles (e.g., Li7La3Zr2O). 12 ), solid particles of the perovskite type (e.g. Li 3x La 2 / 3-x TiO3, where 0 < x < 0.167), NASICON-type solid particles (e.g. Li 1,4 Al 0,4 Ti 1,6 (PO 4)3 , Li 1+x Al x Ge 2-x (PO 4)3 (with 0 ≤ x ≤ 2) (LAGP)) and / or LISICON-type solid particles (e.g. Li 2+2x Zn 1-x GeO4, with 0 < x < 1). In other variants, the solid electrolyte particles 30 can, for example, contain metal-doped or aliovalently substituted oxide solid particles. The metal-doped or aliovalently substituted oxide solid particles can be Li7La3Zr2O doped with aluminum (Al) or niobium (Nb). 12 , antimony (Sb)-doped Li7La3Zr2O 12, Li7La3Zr2O substituted with gallium (Ga) 12 , LiSn2P3O substituted with chromium (Cr) and / or vanadium (V) 12 , and / or Li substituted with aluminium (Al) 1+x+y Al x Ti 2-x Si Y P 3-y O 12 (where 0 < x < 2 and 0 < y < 3). In further variants, the solid electrolyte particles 30 can, for example, contain halide-based solid particles. The halide-based solid particles can be Li3YCl6, Li3InCl6, Li3YBr6, Li11, Li2CdC I4 , Li2MgC I4The solid electrolyte particles 30 may include LiCdI4, Li2ZnI4, Li3OCl, and combinations thereof. In other variants, the solid electrolyte particles 30 may, for example, comprise hydride-based solid particles. These hydride-based solid particles may include LiBH4, LiBH4-LiX (with x = Cl, Br, or I), LiNH2, Li2NH, LiBH4-LiNH2, Li3AlH6, and combinations thereof. In yet other variants, the solid electrolyte particles 30 may comprise a combination of oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles, and / or other solid electrolyte particles with low grain boundary resistance.

[0048] The fibrillated polymers 38 form a structural framework for the solid electrolyte particles 30. The fibrillated polymers 38 can, for example, extend between the solid electrolyte particles 30 and, in certain variants, also connect them. In certain variants, the fibrillated polymers 38 can contain polytetrafluoroethylene (PTFE) fibrils. The polytetrafluoroethylene (PTFE) fibrils can have an average length of more than or equal to approximately 2 micrometers (µm) to less than or equal to approximately 100 µm, a softening point of more than or equal to approximately 260 °C to less than or equal to approximately 327 °C, and a molecular weight of more than or equal to approximately 10 5 g / mol to less than or equal to approximately 10 9g / mol. In other variants, the fibrillated polymers can consist of 38 fluorinated ethylene propylene (FEP) fibrils with an average length of more than or equal to approximately 2 µm to less than or equal to approximately 100 µm, a softening point of more than or equal to approximately 204 °C to less than or equal to approximately 260 °C, and a molecular weight of more than or equal to approximately 10 5 g / mol to less than or equal to approximately 10 9 g / mol. In further variants, the fibrillated polymers can comprise 38 perfluoroalkoxyalkane (PFA) fibrils with an average length of more than or equal to approximately 2 µm to less than or equal to approximately 100 µm, a softening point of more than or equal to approximately 260 °C to less than or equal to approximately 315 °C, and a molecular weight of more than or equal to approximately 10 5 g / mol to less than or equal to approximately 10 9g / mol. In other variants, the fibrillated polymers can contain 38 ethylenetetrafluoroethylene (ETFE) fibrils with an average length of more than or equal to approximately 2 µm to less than or equal to approximately 100 µm, a softening point of more than or equal to approximately 120 °C to less than or equal to approximately 265 °C, and a molecular weight of more than or equal to approximately 10 5 g / mol to less than or equal to approximately 10 9g / mol. In further variants, the fibrillated polymers 38 can contain a combination of polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylene propylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, and / or ethylenetetrafluoroethylene (ETFE) fibrils. As discussed in more detail below, the fibrillated polymers 38 can be prepared using a dispersion process in which a precursor material (e.g., polytetrafluoroethylene (PTFE) binder) has an average particle size of more than or equal to about 1 µm to less than or equal to about 2,000 µm, optionally more than or equal to about 1 µm to less than or equal to about 1,000 µm, and, for certain aspects, optionally more than or equal to about 400 µm to less than or equal to about 700 µm.

[0049] The gel polymer electrolyte 28 comprises a polymer host and a liquid electrolyte. For example, the gel polymer electrolyte 28 may contain more than or equal to approximately 0.1 wt% to less than or equal to approximately 50 wt%, and optionally, in certain aspects, more than or equal to approximately 2 wt% to less than or equal to approximately 30 wt% of the polymer host; and more than or equal to approximately 5 wt% to less than or equal to approximately 90 wt%, and optionally, in certain aspects, more than or equal to approximately 50 wt% to less than or equal to approximately 80 wt% of the liquid electrolyte. In certain variants, the polymer host may be selected from the group consisting of: polyethylene oxide (PEO), polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), polymethyl methacrylate (PMMA), carboxymethylcellulose (CMC), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and combinations thereof.

[0050] The liquid electrolyte contains, for example, more than or equal to approximately 5 wt% to less than or equal to approximately 70 wt%, and optionally, in certain aspects, more than or equal to approximately 10 wt% to less than or equal to approximately 50 wt% of a lithium salt, and more than or equal to approximately 30 wt% to less than or equal to approximately 95 wt%, and optionally, in certain aspects, more than or equal to approximately 50 wt% to less than or equal to approximately 90 wt% of a solvent. The lithium salt contains a lithium cation (Li+) and an anion selected from the group consisting of: hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI). - ), Perchlorate, Tetrafluoroborate, Cyclo-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), Bis(trifluoromethanesulfonyl)imide (TFSI), Bis(perfluorethanesulfonyl)imide (BETI), Bis(oxalate)boarate (BOB), Difluoro(oxalato)borate (DFOB), Bis(fluoromalonato)borate (BFMB) and combinations thereof.

[0051] The solvent dissolves the lithium salt to enable good lithium ion conductivity and simultaneously exhibits a low vapor pressure (e.g., less than approximately 10 mmHg at 25 °C) suitable for the cell manufacturing process. In various aspects, the solvent includes, for example, carbonate solvents (such as ethylene carbonate (EC), propylene carbonate (PC), glycerol carbonate, vinylene carbonate, fluoroethylene carbonate, 1,2-butylene carbonate, and the like), lactones (such as γ-butyrolactone (GBL), δ-valerolactone, and the like), nitriles (e.g., succinonitrile, glutaronitrile, adiponitrile, and the like), sulfones (e.g., tetramethylenesulfone, ethyl methylsulfone, vinylsulfone, phenylsulfone, 4-fluorophenylsulfone, benzylsulfone, and the like), ethers (e.g.,Triethylene glycol dimethyl ether (Triglyme, G3), tetraethylene glycol dimethyl ether (Tetraglyme, G4), 1,3-dimethyloxypropane, 1,4-dioxane and the like), phosphates (such as triethyl phosphate, trimethyl phosphate and the like), ionic liquids, including, for example, ionic liquid cations (e.g., 1-ethyl-3-methylimidazolium ([Emim. ]+ ), 1-propyl-1-methylpiperidinium ([PP 13 ]+ ), 1-Butyl-1-methylpiperidinium ([PP 14 ]+ ), 1-Methyl-1-ethylpyrrolidinium ([Pyr 12 ]+ ), 1-propyl-1-methylpyrrolidinium ([Pyr 13 ]+ ), 1-Butyl-1-methylpyrrolidinium ([Pyr 14 ]+ ), and the like) and anions of ionic liquids (e.g. bis(trifluoromethanesulfonyl)imide (TFSI), bis(fluorosulfonylimide (FS) and the like) and combinations thereof.

[0052] The electrolyte layer 26 can be in the form of a layer with an average thickness of more than or equal to about 2 µm to less than or equal to about 100 µm, optionally more than or equal to about 20 µm to less than or equal to about 60 µm, and optionally about 50 µm for certain aspects. The electrolyte layer 26 can contain: more than or equal to about 70 wt.% to less than or equal to about 99 wt.%, and optionally more than or equal to about 80 wt.% to less than or equal to about 90 wt.% of the solid electrolyte particles 30; more than or equal to about 0.1 wt.% to less than or equal to about 10 wt.%, and optionally more than or equal to about 0.1 wt.% to less than or equal to about 3 wt.% of the fibrillated polymers 38; and more than or equal to approximately 0.1 wt.% to less than or equal to approximately 20 wt.% and, in certain aspects, optionally more than or equal to approximately 0.1 wt.%.-% to less than or equal to approximately 15 wt% of the gel polymer electrolyte.

[0053] With renewed reference to Fig. 1. The negative electrode 22 can be formed from a lithium host material that can function as the negative terminal of a lithium-ion battery. In certain variants, the negative electrode 22 can, for example, be defined by a plurality of negative electroactive solid particles 50. In certain cases, as shown, the negative electrode 22 is a composite material comprising a mixture of the negative electroactive solid particles 50 and the second plurality of solid electrolyte particles 90. For example, the negative electrode 22 can contain more than or equal to about 30 wt.% to less than or equal to about 98 wt.% and, in certain aspects, optionally more than or equal to about 50 wt.% to less than or equal to about 95 wt.% of the negative electroactive solid particles 50, and more than or equal to 0 wt.% to less than or equal to about 50 wt.% and, in certain aspects, optionally more than or equal to about 5 wt.%.-% to less than or equal to approximately 20 wt% of the second plurality of solid electrolyte particles 90. In each variant, the negative electrode 22 can be in the form of a layer with an average thickness of more than or equal to approximately 10 µm to less than or equal to approximately 5,000 µm and, in certain aspects, optionally more than or equal to approximately 10 µm to less than or equal to approximately 100 µm.

[0054] The negative electroactive solid particles 50 can be lithium-based, for example, on a lithium alloy or a lithium metal. In other variants, the negative electroactive solid particles 50 can be silicon-based, e.g., on a silicon alloy and / or a silicon-graphite mixture. In still other variants, the negative electrode 22 can be a carbon-containing anode, and the negative electroactive solid particles 50 can comprise one or more negative electroactive materials, e.g., graphite, graphene, hard carbon, soft carbon, and carbon nanotubes (CNTs). In yet other variants, the negative electrode 22 can comprise one or more negative electroactive materials such as lithium titanium oxide (Li₄Ti₅O₆). 12), comprising one or more metal oxides such as TiO2 and / or V2O5 and / or metal sulfides such as FeS. The negatively electroactive solid particles can be selected from the group which includes, for example, lithium, graphite, graphene, hard carbon, soft carbon, carbon nanotubes, silicon, silicon-containing alloys, tin-containing alloys and / or other lithium-accumulating materials.

[0055] The second set of solid electrolyte particles 90 can be the same as or different from the first set of solid electrolyte particles 30. For example, the second set of solid electrolyte particles 90 can include oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles, and / or other solid electrolyte particles with low grain boundary resistance.

[0056] Although not shown, the negative electrode 22 may, in certain variants, further contain one or more conductive additives and / or binders. The negative electroactive solid particles 50 (and / or the second variety of solid electrolyte particles 90) may optionally be mixed with one or more electrically conductive materials (not shown) that provide an electron conduction path, and / or at least one polymeric binder (not shown) that enhances the structural integrity of the negative electrode 22. For example, the negative electrode may contain more than or equal to 0 wt% to less than or equal to about 30 wt% and, in certain aspects, optionally more than or equal to about 2 wt% to less than or equal to about 10 wt% of the one or more electrically conductive additives; and more than or equal to 0 wt% to less than or equal to about 20 wt%.-% and, in certain aspects, optionally more than or equal to approximately 1 wt.% to less than or equal to approximately 10 wt.% of one or more binders.

[0057] The negatively electroactive solid particles 50 (and / or the second set of solid electrolyte particles 90) can optionally be mixed with binders such as sodium carboxymethylcellulose (CMC), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer rubber (EPDM), nitrile butadiene rubber (NBR), styrene-butadiene rubber (SBR), polyethylene glycol (PEO), and / or lithium polyacrylate (LiPAA). Electrically conductive materials can be, for example, carbon-based materials or a conductive polymer. Examples of carbon-based materials include graphite particles, acetylene black (such as KETCHEN™ black or DENKA™ black), carbon nanofibers and nanotubes, graphene (such as graphene oxide), carbon black (such as Super P), and the like.Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like. In certain applications, mixtures of conductive additives and / or binders can also be used.

[0058] The positive electrode 24 can consist of a lithium-based or electroactive material capable of storing and releasing lithium while serving as the positive terminal of the battery 20. In certain variants, the positive electrode 24 can, for example, be formed by a multitude of positive electroactive solid particles 60. In certain cases, as shown, the positive electrode 24 is a composite material comprising a mixture of the positive electroactive solid particles 60 and a third multitude of solid electrolyte particles 92. For example, the positive electrode 24 can contain more than or equal to about 30 wt% to less than or equal to about 98 wt%, and in certain aspects optionally more than or equal to about 50 wt% to less than or equal to about 95 wt%, of the positive electroactive solid particles 60, and more than or equal to 0 wt% to less than or equal to about 50 wt%.-% and, in certain aspects, optionally more than or equal to approximately 5 wt.% to less than or equal to approximately 20 wt.% of the third plurality of solid electrolyte particles 92. In each variant, the positive electrode 24 can be in the form of a layer with an average thickness of more than or equal to approximately 10 µm to less than or equal to approximately 5,000 µm and, in certain aspects, optionally more than or equal to approximately 10 µm to less than or equal to approximately 100 µm.

[0059] In certain variants, the positive electrode 24 can consist of a layered oxide cathode, a spinel cathode, or a polyanion cathode. For example, in a layered oxide cathode (e.g., rock salt layered oxides), the positive electroactive solid particles 60 can comprise one or more positive electroactive materials made of LiCoO2, LiNi, or similar materials. x Mn y Co 1-x-y O2 (with 0 ≤ x ≤ 1 and 0 ≤ y ≤ 1) are selected, LiNi x Mn yAl 1-x-y O2 (with 0 < x ≤ 1 and 0 < y ≤ 1), LiNi x Mn 1-x O2 (with 0 ≤ x ≤ 1) and Li 1+x MO2 (with 0 ≤ x ≤ 1) for lithium-ion solid-state batteries. The spinel cathode can contain one or more positive electroactive materials, such as LiMn2O4 and LiNi. 0,5 Mn 1,5 O4. The polyanion cation can be, for example, a phosphate such as LiFePO4, LiVPO4, LiV2(PO4). 4)3 , Li₂FePO₄F, Li₃Fe₃(PO₄)₄ or Li₃V₂(PO₄)F₃ for lithium-ion batteries and / or a silicate such as LiFeSiO₄ for lithium-ion batteries. The positive electroactive solid particles 60 can comprise one or more positive electroactive materials selected from the group consisting of LiCoO₂, LiNi x Mn y Co 1-x-y O2 (with 0 ≤ x ≤ 1 and 0 ≤ y ≤ 1), LiNi x Mn 1-x O2 (with 0 ≤ x ≤ 1), Li 1+x MO2 (with 0 ≤ x ≤ 1), LiMn2O4, LiNi x Mn 1,5O4, LiFePO4, LiVPO4, LiV2(PO4)3, Li2FePO4F, Li3Fe3(PO4)4, Li3V2(PO4)F3, LiFeSiO4 and combinations thereof. In certain aspects, the positive electroactive solid particles can be coated (e.g., with LiNbO3 and / or Al2O3) and / or the positive electroactive material can be doped (e.g., with aluminum and / or magnesium).

[0060] The third set of solid electrolyte particles 92 can be the same as or different from the first and / or second sets of solid electrolyte particles 30, 90. For example, the third set of solid electrolyte particles 92 can include oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles, and / or other solid electrolyte particles with low grain boundary resistance.

[0061] Although not shown, the positive electrode 24 may, in certain variants, further contain one or more conductive additives and / or binders. The positive electroactive solid particles 60 (and / or the third variety of solid electrolyte particles 92) may optionally be mixed with one or more electrically conductive materials (not shown) that provide an electron conduction path and / or at least one polymeric binder (not shown) that enhances the structural integrity of the positive electrode 24. For example, the positive electrode 24 may contain more than or equal to 0 wt% to less than or equal to about 30 wt% and, in certain aspects, optionally more than or equal to about 2 wt% to less than or equal to about 10 wt% of the one or more electrically conductive additives; and more than or equal to 0 wt% to less than or equal to about 20 wt%.-% and, in certain aspects, optionally more than or equal to approximately 1 wt.% to less than or equal to approximately 10 wt.% of one or more binders.

[0062] The one or more conductive materials that are optionally mixed with the positive electroactive solid particles 60 (and / or the third plurality of solid electrolyte particles 92) can be the same as or different from the one or more conductive materials that are optionally mixed with the negative electroactive solid particles 50 (and / or the second plurality of solid electrolyte particles 90). The one or more binders that are optionally mixed with the positive electroactive solid particles 60 (and / or the third plurality of solid electrolyte particles 92) can be the same as or different from the one or more binders that are optionally mixed with the negative electroactive solid particles 50 (and / or the second plurality of solid electrolyte particles 90).

[0063] In various aspects, the present disclosure provides methods for the production of electrolyte layers comprising a porous film defined by a plurality of solid electrolyte particles and fibrillated polymers, as well as a gel-polymer electrolyte that at least partially fills the pores of the porous film. For example, it illustrates Fig. 2 an example procedure 200 for the formation of an exemplary electrolyte layer, such as that in Fig. 1 Electrolyte layer 26. As shown, the process 200 comprises the forming 210 of a freestanding porous film and the loading 250 of the freestanding porous film with a gel polymer electrolyte. In certain variations, the forming 210 may include the contacting 212 of a plurality of solid electrolyte particles and one or more polymers capable of forming fibers, e.g., fibrillates, in the presence of compressive shear forces. The one or more polymers may, for example, include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), and / or ethylenetetrafluoroethylene (ETFE). The solid electrolyte particles may include oxide-based solid particles, metal-doped or aliovalent-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles and / or other solid electrolyte particles with low grain boundary resistance.

[0064] In certain variants, the contacting process 212 may include the formation of a mixture and the mixing of the mixture to form a powder containing the plurality of solid electrolyte particles and a plurality of polymer fibers that connect or adhere to the solid electrolyte particles. The mixture may further contain a processing solvent such as ethanol, isopropanol, and / or water. For example, the mixture may contain more than or equal to about 50 wt.% to less than or equal to about 80 wt.% of the solid electrolyte particles, more than or equal to about 0.01 wt.% to less than or equal to about 10 wt.% of the fiber-forming polymers, and more than or equal to about 0 wt.% to less than or equal to about 30 wt.% of the processing solvent. The shaping process 210 may further include the preparation of a precursor film 214 (e.g.,The process 200 comprises the forming of a powder-feed forming machine and the calendering 216 of the precursor film to form the freestanding porous film. Although not shown, in certain variations the process 200 may also include one or more drying or heating steps before or after the calendering 216. In any case, the freestanding porous film may have an average thickness of more than or equal to about 2 µm to less than or equal to about 100 µm and a porosity of more than or equal to about 20 volume percent to less than or equal to about 50 volume percent.

[0065] Loading 250 of the freestanding porous film with a gel-polymer electrolyte can include contacting 252 of the freestanding porous film with a gel precursor solution, such that the gel precursor solution penetrates cavities or pores and grain boundaries between the solid electrolyte particles and the polymer fibers. In certain variations, contacting 252 can include immersing the freestanding porous film in a bath containing the gel precursor solution in a roll-to-roll process. The gel precursor solution contains a polymer host, a liquid electrolyte, and an additional solvent. For example, the gel precursor can contain more than or equal to about 2 wt% to less than or equal to about 20 wt% of the polymer host, more than or equal to about 30 wt% to less than or equal to about 70 wt% of the liquid electrolyte, and more than or equal to about 10 wt% to less than or equal to about 50 wt% of the additional solvent.

[0066] As stated above, the polymer host may be selected from the group consisting of: polyethylene oxide (PEO), polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), polymethyl methacrylate (PMMA), carboxymethylcellulose (CMC), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and combinations thereof; and the liquid electrolyte may contain more than or equal to approximately 5 wt% to less than or equal to approximately 70 wt%, and in certain aspects optionally more than or equal to approximately 10 wt% to less than or equal to approximately 50 wt%, of a lithium salt and more than or equal to approximately 30 wt% to less than or equal to approximately 95 wt%, and in certain aspects optionally more than or equal to approximately 50 wt% to less than or equal to approximately 90 wt%, of a first solvent. The additional solvent may be selected from the group consisting of: dimethyl carbonate (DMC), ethyl acetate, acetonitrile, ethyl methyl carbonate, and combinations thereof.The additional solvent has a first evaporation temperature that is lower than the second evaporation temperature of the first solvent.

[0067] Loading the freestanding porous film with a gel-polymer electrolyte can also include removing the additional solvent used to form the electrolyte layer. In certain variations, the additional solvent can be removed by heating. For example, the freestanding porous film containing the gel-polymer electrolyte can be moved through a controlled-temperature oven.

[0068] Certain features of current technology are explained in more detail in the following non-restrictive examples. Example 1

[0069] Exemplary battery cells can be manufactured according to various aspects of the present disclosure.

[0070] An exemplary electrolyte layer 310 may, for example, comprise a porous film defined by a multitude of solid electrolyte particles and fibrillated polymers, as well as a gel-polymer electrolyte that at least partially fills cavities or pores and grain boundaries in the porous film. A comparable solid electrolyte layer 320 may contain the multitude of solid electrolyte particles but omits the fibrillated polymers and the gel-polymer electrolyte.

[0071] Fig. Figure 3A is a graphical representation showing the impedance of the exemplary electrolyte layer 310 compared to the comparable solid electrolyte layer 320, where the x-axis 302 represents the real impedance (ohms) and the y-axis 304 the imaginary impedance (ohms). As shown, the exemplary electrolyte layer 310 has a significantly lower resistance than the comparable solid electrolyte layer 320.

[0072] Fig. Figure 3B is a graphical representation showing the capacity retention at room temperature of the exemplary electrolyte layer 310 compared to the comparable solid-state electrolyte layer 320, where the x-axis 312 represents the number of cycles and the y-axis 314 represents the capacity retention (%). As shown, the exemplary electrolyte layer 310 has good cycle performance at room temperature and a rate of 1C.

[0073] Fig. 3C is a graphical representation that shows the area conductance (Ohm / cm²). 2 Figure 322 shows the performance of an exemplary electrolyte layer 310 at -18 °C compared to the comparable solid electrolyte layer 320, where the x-axis 322 represents the capacity retention (%) and the y-axis 324 represents the voltage (V). As shown, the exemplary electrolyte layer 310 has good low-temperature performance.

[0074] The foregoing description of the embodiments serves only for illustration and description. It makes no claim to completeness or to limit disclosure.

Claims

[1] Electrolyte layer (26) for use in an electrochemical cell (20) which circulates lithium ions, the electrolyte layer (26) comprising: a porous film defining a multitude of cavities and comprising a multitude of solid electrolyte particles (30) and a multitude of polymer fibrils (38) connecting the solid electrolyte particles (30); and a gel polymer electrolyte (28) that at least partially fills the multitude of cavities in the porous film, wherein the polymeric fibrils (38) are selected from the group consisting of: polytetrafluoroethylene (PTFE) fibrils, fluorinated ethylene propylene (FEP) fibrils, perfluoroalkoxyalkane (PFA) fibrils, ethylenetetrafluoroethylene (ETFE) fibrils and combinations thereof, wherein each of the polymeric fibrils (38) has a fiber length of more than or equal to 2 micrometers to less than or equal to 100 micrometers and a molecular weight of more than or equal to 10 5 g / mol to less than or equal to 10 9 g / mol. [2] Electrolyte layer (26) according to claim 1, wherein the solid electrolyte particles (30) have an ionic conductivity of more than or equal to 0.1 mS / cm to less than or equal to 20 mS / cm at more than or equal to 20 °C to less than or equal to 22 °C, wherein the majority of the solid electrolyte particles (30) are selected from the group consisting of: oxide-based solid particles, metal-doped or aliovalently-substituted oxide solid particles, halide-based solid particles, hydride-based solid particles and combinations thereof. [3] Electrolyte layer (26) according to claim 1, wherein the polytetrafluoroethylene (PTFE) fibrils have a softening point of more than or equal to 260 °C to less than or equal to 327 °C, the fluorinated ethylene propylene (FEP) fibrils have a softening point of more than or equal to 204 °C to less than or equal to 260 °C, and The ethylenetetrafluoroethylene (ETFE) fibrils have a softening point of more than or equal to 260 °C to less than or equal to 315 °C. [4] Electrolyte layer (26) according to claim 1, wherein the gel polymer electrolyte (28) comprises: more than or equal to 0.1 wt.% to less than or equal to 50 wt.% of a polymer host; and more than or equal to 5 wt.% to less than or equal to 90 wt.% of a liquid electrolyte. [5] Electrolyte layer (26) according to claim 4, wherein the polymer host is selected from the group consisting of: Polyethylene oxide (PEO), Polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), Polymethyl methacrylate (PMMA), Carboxymethylcellulose (CMC), Polyacrylonitrile (PAN), Polyvinylpyrrolidone (PVP) and combinations thereof. [6] Electrolyte layer according to (26) claim 1, wherein the porous film has a porosity of more than or equal to 10 vol% to less than or equal to 50 vol% and the gel polymer electrolyte (28) fills more than or equal to 60% to less than or equal to 100% of a total porosity defined by the plurality of cavities of the porous film. [7] Electrolyte layer (26) according to claim 1, wherein the porous film comprises more than or equal to 70 wt.% to less than or equal to 99 wt.% of the plurality of solid electrolyte particles (30), more than or equal to 0.1 wt.% to less than or equal to 10 wt.% of the plurality of polymer fibrils (38), and more than or equal to 0.1 wt% to less than or equal to 20 wt% of the gel polymer electrolyte (28). [8] Electrolyte layer (26) according to claim 1, wherein the electrolyte layer (26) has an average thickness of more than or equal to 2 micrometers to less than or equal to 100 micrometers.

Images