Solid-state polymer electrolyte used in production of all-solid-state alkali ion batteries

Abstract

Systems and methods for synthesizing solid state polymer electrolytes and / or using solid state polymer electrolytes in the production of all-solid-state alkali-ion batteries are provided.

Description

[0001] Claiming priority

[0002] This patent application references and claims priority and benefit to U.S. Provisional Patent Application No. 62 / 952,189, filed December 20, 2019, and U.S. Patent Application No. 16 / 739,732, filed January 10, 2020. The entire applications are incorporated herein by reference. Technical Field

[0003] This disclosure relates to aspects of energy generation and storage. More specifically, certain embodiments of this disclosure relate to methods and systems for synthesizing solid polymer electrolytes for use in the production of all-solid-state alkaline ion batteries. Background Technology

[0004] Conventional battery technologies can have various problems. In this regard, conventional systems and methods (if available) used for designing and fabricating battery anodes can be expensive, cumbersome, and / or inefficient; for example, they may be complex and / or time-consuming to implement and may limit battery life.

[0005] Other limitations and disadvantages of conventional and traditional methods will become apparent to those skilled in the art by comparing such a system with some aspects of this disclosure as set forth with reference to the accompanying drawings in the remainder of this application. Summary of the Invention

[0006] Systems and methods for synthesizing solid polymer electrolytes for use in the production of all-solid-state alkaline ion batteries are provided, generally as shown in at least one figure and / or as described with respect to at least one figure, as set forth more fully in the claims.

[0007] These and other advantages, aspects and novel features of this disclosure, as well as details of the embodiments shown therein, will be more fully understood from the following description and accompanying drawings. Attached Figure Description

[0008] Figure 1 This is a diagram of a battery having a silicon-dominant anode, according to an exemplary embodiment of this disclosure.

[0009] Figure 2 An exemplary silicon-dominant anode is illustrated in an exemplary embodiment according to this disclosure.

[0010] Figure 3 This is a flowchart of a method for directly coating an electrode according to an exemplary embodiment of the present disclosure.

[0011] Figure 4 This is a flowchart of an alternative method for transferring laminated electrodes according to an exemplary embodiment of the present disclosure.

[0012] Figure 5 An exemplary battery structure based on an exemplary solid-state electrolyte is illustrated according to an exemplary embodiment of the present disclosure.

[0013] Figure 6 This is a graph illustrating the attenuated total reflectance (ATR) / Fourier transform infrared (FTIR) spectrum of an exemplary solid electrolyte according to an exemplary embodiment of the present disclosure.

[0014] Figure 7 This is a Nyquist plot illustrating an exemplary embodiment of a battery based on an exemplary solid-state electrolyte according to the present disclosure.

[0015] Figure 8 This is a diagram illustrating the voltage distribution of a battery based on an exemplary solid-state electrolyte according to an exemplary embodiment of the present disclosure.

[0016] Figure 9 This is a graph illustrating the cyclic voltammetry response of an exemplary solid electrolyte according to an exemplary embodiment of the present disclosure.

[0017] Figure 10 This is a graph illustrating the cyclic voltammetry response of another exemplary solid electrolyte according to an exemplary embodiment of the present disclosure.

[0018] Figure 11 This is a graph illustrating the cyclic voltammetry response of another exemplary solid electrolyte according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0019] Figure 1 This is a diagram of a cell with a silicon-dominant anode according to an exemplary embodiment of this disclosure. Reference Figure 1 A battery 100 is shown, comprising a separator 103 sandwiched between an anode 101 and a cathode 105, and current collectors 107A and 107B. A load 109 coupled to the battery 100 is also shown, illustrating the situation when the battery 100 is in a discharge mode. In this disclosure, the term "battery" can be used to refer to a single electrochemical cell, multiple electrochemical cells formed as modules, and / or multiple modules formed as components.

[0020] The development of portable electronic devices and the electrification of transportation have driven the demand for high-performance electrochemical energy storage. Compared to other rechargeable battery chemicals, small-scale (<100 Wh) to large-scale (>10 kWh) devices primarily use lithium-ion batteries due to their high performance.

[0021] Anode 101 and cathode 105, together with current collectors 107A and 107B, may include electrodes, which may be contained within an electrolyte material or in a plate or membrane that houses the electrolyte material. The plate may provide a physical barrier for containing the electrolyte and conductive contact with an external structure. In other embodiments, the anode / cathode plates are immersed in the electrolyte, while a housing provides electrolyte containment. Anode 101 and cathode 105 are electrically coupled to current collectors 107A and 107B, which contain metal or other conductive material to provide electrical contact with the electrodes and physical support for the active material during electrode formation.

[0022] Figure 1 The configuration shown illustrates a battery 100 in a discharge mode, while in a charging configuration, a charger can be used instead of load 107 to reverse the process. In one type of battery, separator 103 is typically a membrane material made of, for example, an electrically insulating polymer, which prevents electrons from flowing from anode 101 to cathode 105, or vice versa, while being porous enough to allow ions to pass through separator 103. Typically, separator 103, cathode 105, and anode 101 materials are formed as sheets, films, or foils coated with active materials, respectively. Sheets of cathode, separator, and anode are sequentially stacked or rolled such that separator 103 separates cathode 105 from anode 101 to form battery 100. In some embodiments, separator 103 is a sheet and is typically manufactured using winding and stacking methods. In these methods, anode, cathode, and current collector (e.g., electrodes) may comprise membranes.

[0023] In an exemplary embodiment, battery 100 may comprise a solid, liquid, or gel electrolyte. Separator 103 is preferably insoluble in typical battery electrolytes, and may comprise, for example, compositions containing dissolved lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate monohydrate (LiAsF6), lithium perchlorate (LiClO4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium difluoro(oxalate)borate (LiDFOB), lithium bis(oxalate)borate (LiBOB), lithium trifluoromethanesulfonate (LiCF3SO3), lithium tetrafluorooxalate phosphate (LTFOP), lithium difluorophosphate (LiPO2F2), and pentafluorophosphate. Lithium trifluoroborate (LiFAB), lithium 2-trifluoromethyl-4,5-dicyanimidazolium lithium (LiTDI), lithium bis(2-fluoromalonic acid alkyl)borate (LiBFMB), lithium 4-pyridyltrimethylborate (LPTB), lithium 2-fluorophenol trimethylborate (LFPTB), lithium catechol dimethylborate (LiCDMB), etc., are used in the following forms: ethylene carbonate (EC), fluoroethylene carbonate (FEC), difluoroethylene carbonate (DiFEC), trifluoropropylene carbonate (TFPC), ethylene carbonate (VC), propylene carbonate (PC), dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), etc.

[0024] The separator 103 can be wetted or soaked with a liquid or gel electrolyte. Furthermore, in an exemplary embodiment, the separator 103 does not melt at temperatures below about 100°C to 120°C and exhibits sufficient mechanical properties for battery applications. During operation, the battery can undergo expansion and contraction of the anode and / or cathode. In an exemplary embodiment, the separator 103 can expand and contract by at least about 5% to 10% without failure and can also be flexible.

[0025] The separator 103 can be porous enough that ions can pass through it once wetted with, for example, a liquid or gel electrolyte. Alternatively (or additionally), the separator can absorb electrolytes by gelation or other methods, even without significant porosity. The porosity of the separator 103 is generally not so high that it allows electrons to be transferred between the anode 101 and the cathode 105.

[0026] Anode 101 and cathode 105 include electrodes for battery 100, providing electrical connection to means for transferring charge in charging and discharging states. For example, anode 101 may comprise silicon, carbon, or a combination of these materials. Typical anode electrodes comprise carbon materials and include current collectors such as copper sheets. Carbon is commonly used because it has excellent electrochemical properties and is also conductive. Anodes currently used in rechargeable lithium-ion batteries typically have a specific capacity of about 200 mAh / g. Graphite, the active material used in most lithium-ion battery anodes, has a theoretical energy density of 372 mAh / g. In contrast, silicon has a high theoretical capacity of 4200 mAh / g at high temperatures and 3579 mAh / g at room temperature. To increase the volumetric and gravimetric energy densities of lithium-ion batteries, silicon can be used as the active material for the cathode or anode. Silicon anodes can be formed from, for example, silicon composites having more than 50% silicon.

[0027] In this exemplary embodiment, anode 101 and cathode 105 store ions, such as lithium, for charge separation. In this example, the electrolyte carries positively charged lithium ions from anode 101 to cathode 105 in discharge mode, for example as... Figure 1 As shown, and conversely, in charging mode, current flows through separator 103. The movement of lithium ions generates free electrons in anode 101, which creates a charge at positive current collector 107B. Current then flows from said current collector through load 109 to negative current collector 107A. Separator 103 blocks the flow of electrons within battery 100, allows the flow of lithium ions, and prevents direct contact between electrodes.

[0028] When the battery 100 discharges and provides current, lithium ions are released from the anode 101 and reach the cathode 105 via the separator 103, thereby generating an electron flow from one side to the other via the connected load 109. When the battery is charged, the opposite occurs, in which lithium ions are released by the cathode 105 and received by the anode 101.

[0029] The materials selected for the anode 101 and cathode 105 are important for the potential reliability and energy density of the battery 100. Current lithium-ion batteries need improvements in energy, power, cost, and safety to compete, for example, with internal combustion engine (ICE) technology and allow for the widespread adoption of electric vehicles (EVs). With the development of high-capacity, high-voltage cathodes, high-capacity anodes, and functional, non-flammable electrolytes with high voltage stability and interfacial compatibility with the electrodes, lithium-ion batteries with high energy density, high power density, and improved safety have been achieved. Furthermore, using materials with low toxicity as battery materials is beneficial for reducing process costs and promoting consumer safety.

[0030] While the performance of electrochemical electrodes depends on many factors, it largely depends on the robustness of the electrical contacts between electrode particles and between the current collector and electrode particles. The conductivity of silicon anode electrodes can be controlled by incorporating conductive additives with different morphological properties. Carbon black (Super-P), vapor-grown carbon fiber (VGCF), graphite, graphene, and / or mixtures thereof have previously been individually incorporated into anode electrodes, resulting in improved anode performance. The synergistic interaction between the two carbon materials can promote electrical contact during the large volume changes of the silicon anode during charging and discharging.

[0031] Existing lithium-ion batteries typically use graphite-dominant anodes as the lithium intercalation material. However, silicon-dominant anodes offer improvements compared to graphite-dominant lithium-ion batteries. Silicon exhibits high gravimetric capacity (3579 mAh / g vs. 372 mAh / g for graphite) and volumetric capacity (2194 mAh / L vs. 890 mAh / L for graphite). Furthermore, silicon-based anodes show advantages over Li / Li... + It exhibits a lithiation / delithiation voltage plateau in the range of approximately 0.3 V to 0.4 V, which maintains its open-circuit potential and prevents undesirable Li precipitation and dendrite formation. While silicon displays excellent electrochemical activity, achieving stable cycle lifetime for silicon-based anodes is challenging due to the large volume changes during lithiation and delithiation. The silicon region may lose electrical contact with the anode because the large volume changes, combined with its low conductivity, separate the silicon from the surrounding material in the anode.

[0032] Furthermore, large silicon volume changes exacerbate the formation of the solid electrolyte interphase (SEI), which can further lead to electrical insulation and thus capacity loss. During charge-discharge cycling, the expansion and contraction of silicon particles cause particle fragmentation, increasing their specific surface area. As the silicon surface area changes and increases between cycles, the SEI repeatedly disintegrates and reassembles. Therefore, the SEI continuously accumulates around the fragmented silicon regions during cycling, forming a thick electronic and ionic insulating layer. This accumulated SEI increases electrode impedance and reduces electrode electrochemical reactivity, which is detrimental to cycle life.

[0033] In various embodiments according to this disclosure, solid-state electrolytes optimized for alkaline-ion (e.g., lithium-ion) batteries and used to enhance the performance of such batteries can be used. In this regard, with the continued advancement of electrification, the demand for energy-dense yet safe batteries for energy storage and power is constantly increasing. Pushing the limits of energy density in lithium-ion batteries may be hampered by performance limitations and / or may lead to safety issues. Current alkaline-ion batteries (e.g., lithium-ion batteries) may contain liquid electrolytes (e.g., organic liquid electrolytes). However, the use of such liquid electrolytes may have several disadvantages. For example, many safety issues may arise from the use of organic liquid electrolytes in lithium-ion batteries. In this respect, liquid electrolytes may pose safety hazards, for example, due to volatilization, flammability, and leakage. Furthermore, during battery use, some metal oxide electrodes (e.g., high-nickel NCA or NCM cathodes) may degrade due to chemical reactions with the liquid electrolyte, which may cause processes involving the dissolution, migration, and binding of transition metal ions on the cathode, potentially leading to battery failure. Due to these risks, and the need to increase battery energy density, safer or more optimized alternatives to organic liquid electrolytes in batteries may be desirable.

[0034] Many safety risks and / or performance limitations can be mitigated by replacing the organic liquid electrolytes commonly used in batteries with safer alternatives that offer improved performance, such as solid-state electrolytes. Solid-state electrolytes can be non-flammable and non-volatile, thus being safer than their liquid counterparts while also increasing the battery's energy density. Another benefit of using such solid-state electrolytes is that their reduced reactivity with the cathode can help prevent cathode degradation. However, not all solid-state electrolytes are suitable. For example, the use of inorganic solid-solid electrolytes can have some drawbacks, as these electrolytes may suffer from problems including poor mechanical properties and low elastic modulus. However, organic-based solid-state electrolytes (such as polymers) can be better alternatives, for example, due to their greater flexibility, improved conductivity, and better contact or adhesion to electrode active materials.

[0035] However, despite the benefits of solid-state batteries, their use can be hampered by numerous problems and / or challenges. For example, manufacturing solid-state batteries may require lengthy processes that may include, for instance, mixing solid components at various stages of manufacturing to obtain uniform electrodes and separators, thereby providing acceptable capacity and energy density. Furthermore, even with such time-consuming manufacturing processes, the resulting battery components (anode, cathode, electrolyte / ion-conducting separator) may suffer from a lack of uniformity and insufficient contact between all components due to the solid nature of the materials. Therefore, solid-state batteries may perform poorly compared to typical liquid electrolyte-based batteries. Thus, challenges such as low electrolyte conductivity, high manufacturing costs, and poor performance may commercially limit the production of solid-state batteries.

[0036] Embodiments according to this disclosure overcome and mitigate many challenges and problems that may hinder the use of solid-state batteries. In particular, in various exemplary embodiments, the challenges of manufacturing solid-state batteries can be addressed by providing solid electrolytes with regulated melting points (e.g., <100°C), high mechanical strength, and high electrical conductivity. These combined properties can facilitate the manufacture of solid-state batteries capable of operating at room temperature. For example, the regulated melting point of the solid (e.g., polymer) electrolyte according to this disclosure can allow the production of otherwise unprocessable all-solid-state batteries, such as silicon anode batteries, which can exhibit extremely high volume expansion (e.g., 400%) during lithiation. However, while various embodiments have been described with respect to batteries having silicon-based anodes, this disclosure is not limited to silicon anode batteries.

[0037] Beyond addressing manufacturing challenges, using polymer electrolytes as components in alkaline-ion batteries (e.g., lithium-ion batteries with a Si-dominated anode) can also resolve some safety and performance issues associated with liquid electrolytes and / or other solid-state electrolytes. For example, due to the composition of polymer composites and the corresponding synergistic effects between different components, all-solid-state electrolytes based on polymer blends and composites can exhibit acceptable Li-ion conductivity, good electrochemical stability over a wide voltage window, enhanced thermal stability and mechanical properties, and reduced flammability. Furthermore, such solid-state electrolytes allow the battery to operate at room temperature. Therefore, using such solid-state electrolytes can improve the lifespan and safety of lithium-ion (or alkaline-ion in general) batteries.

[0038] In some implementations, solid-state electrolytes can be injected into the battery structure in a manner similar to that used for liquid electrolytes. For example, molten polymers can be simply injected into the battery in liquid (molten) form, similar to how liquid electrolytes are currently injected into most lithium-ion batteries. The molten polymer electrolyte can wet standard porous electrodes and, most commonly, separators. The molten polymer cools at room temperature and becomes solid.

[0039] The following will be for specific reference. Figures 5 to 11 Exemplary implementations and their performance using solid electrolytes according to this disclosure are described in more detail.

[0040] Figure 2 An exemplary silicon-dominant anode is illustrated according to an exemplary embodiment of this disclosure. Reference Figure 2 The diagram illustrates a current collector 201, an optional binder 203, and an active material 205. However, it should be noted that the binder 203 may be present or absent depending on the type of anode manufacturing process used, as the binder is not necessarily present in a direct coating process in which the active material is formed directly on the current collector.

[0041] In an exemplary embodiment, the active material 205 comprises silicon particles in a binder material and a solvent. The active material 205 is pyrolyzed to transform the binder into glassy carbon, which provides a structural framework around the silicon particles and also provides conductivity. An optional adhesive 203 can be used to attach the active material to the current collector 201. The current collector 201 may comprise a metal film, such as copper, nickel, or titanium, but other conductive foils may be used depending on the required tensile strength.

[0042] Figure 2 Lithium particles grafted onto and lithium-modified active material 205 are also illustrated. For example... Figure 2 As shown, current collector 201 has a thickness t, which can vary depending on the specific implementation. In this regard, a thicker foil can be used in some implementations, while a thinner foil can be used in others. For example, for copper, the thickness of an exemplary thicker foil can be greater than 6 μm, such as 10 μm or 20 μm, while the thickness of a thinner foil can be less than 6 μm.

[0043] In an exemplary embodiment, when an adhesive is used, adhesive 203 comprises a polymer such as polyimide (PI) or polyamide-imide (PAI), which provides adhesive strength between the active material membrane 205 and the current collector 201, while also providing electrical contact with the current collector 201. Other adhesives may be used, depending on the required strength, as long as they can provide adhesive strength with sufficient conductivity after processing.

[0044] Figure 3This is a flowchart of a method for directly coating an electrode according to an exemplary embodiment of this disclosure. The method includes physically mixing an active material, a conductive additive, and a binder together, and directly coating it onto a current collector. This exemplary method includes a direct coating method in which an anode slurry is directly coated onto a copper foil using an adhesive, such as PVDF, CMC, SBR, sodium alginate, PAI, poly(acrylic acid) (PAA), PI, LA133, polyvinyl alcohol (PVA), polyethylene glycol (PEG), Nafion solutions, recently reported conductive polymer adhesives, and mixtures and combinations thereof. Another exemplary method includes forming an active material on a substrate and then transferring it to a current collector, as per [the previous section on...]. Figure 4 As stated above.

[0045] In step 301, the original electrode active material can be mixed using a binder / resin (e.g., PI, PAI), a solvent, and conductive carbon (e.g., Super-P, graphene, VGCF, graphite, or other types of hard / soft carbon, etc.) or combinations thereof. For example, graphene / VGCF (1:1 by weight) can be dispersed in NMP under ultrasonic treatment for, for example, 1 hour, followed by the addition of Super P (1:1:1 with VGCF and graphene) and further ultrasonic treatment for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, for, a period of, for, for, a period of, for, for, a ball mill. Silicon powder with the desired particle size can then be dispersed in polyamic acid resin (15% solids in N-methylpyrrolidone (NMP)) at, for, for, for, a specified time, for, for, for, for, for, a ball mill. A conjugated carbon / NMP slurry can then be added and dispersed for, for, for, another predetermined time, at, for, for, for, for, for, for, for, for, for, to achieve a slurry viscosity of 2000 to 4000 cP and a total solids content of approximately 30%. The particle size and mixing time can be varied to configure the density and / or roughness of the active material.

[0046] In step 303, the slurry can be prepared at, for example, 3 to 4 mg / cm³. 2 The coating is applied to the foil, which can be dried in step 305 to produce a residual solvent content of less than 15%. In step 307, an optional calendering process can be used, in which a series of hard rollers can be used to trim the film / substrate into a smoother and denser sheet of material.

[0047] In step 309, the active material can be pyrolyzed by heating to 500 to 800°C, causing the carbon precursor to be partially or completely converted into glassy carbon. When the anode is heated to 400°C or higher, the pyrolysis step can produce an anode active material with a silicon content greater than or equal to 50% by weight. Pyrolysis can be carried out in a rolling process or after stamping in step 311. If carried out in a rolling process, stamping is performed after the pyrolysis process. The stamped electrodes can then be sandwiched together with a separator and cathode along with an electrolyte to form a battery.

[0048] In step 313, the battery may undergo a formation process that includes initial charging and discharging steps to lithium-ionize the anode, where some residual lithium remains.

[0049] In various embodiments according to this disclosure, a solid-state electrolyte optimized for alkaline-ion (e.g., lithium-ion) batteries and used to enhance the performance of such batteries can be used. Thus, adjustments can be made... Figure 3 The direct coating method described herein addresses the use of such electrolytes. For example, heat treatment of the solid composition can be added to and / or incorporated into this method.

[0050] Figure 4 This is a flowchart of an alternative method for transferring laminated electrodes according to an exemplary embodiment of this disclosure. While previous methods for manufacturing composite anodes employed a direct coating process, this method physically mixes active materials, conductive additives, and binders together and combines them with a peeling and lamination process.

[0051] This method is in Figure 4 The flowchart shows that it begins at step 401, where the active material can be mixed with a binder / resin (e.g., polyimide (PI) or polyamide-imide (PAI)), solvent, other additives, and optional conductive carbon (e.g., Super-P, graphene, VGCF, graphite, or other types of hard / soft carbon, etc.) or a combination thereof. Figure 4The method described herein involves dispersing graphene / VGCF (1:1 by weight) in NMP under ultrasonic treatment for, for example, 45 to 75 minutes, followed by the addition of Super P (1:1:1 with VGCF and graphene) and further ultrasonic treatment for, for example, 1 hour. Silicon powder with the desired particle size can then be dispersed in polyamic acid resin (10 to 20% solids in N-methylpyrrolidone (NMP)) in a ball mill at, for example, 800 to 1200 rpm for a specified time. A conjugated carbon / NMP slurry can then be added and dispersed at, for example, 1800 to 2200 rpm for, for, for, another predetermined time, to achieve a slurry viscosity of 2000 to 4000 cP and a total solids content of approximately 30%. The particle size and mixing time can be varied to configure the density and / or roughness of the active material.

[0052] In step 403, the slurry can be coated onto a polymer substrate, such as polyethylene terephthalate (PET), polypropylene (PP), or Mylar. The slurry can be applied at a concentration of 3 to 4 mg / cm³. 2 A loading amount (with 15% solvent content) is coated onto a PET / PP / Mylar film, and then dried in step 405 to remove a portion of the solvent. An optional calendering process can be used, in which a series of hard rollers are used to trim the film / substrate into a smooth and dense sheet of material.

[0053] In step 407, the green film can then be removed from the PET, where the active material can be peeled off from the polymer substrate. This peeling process is optional for polypropylene (PP) substrates, as PP can leave approximately 2% carbon residue upon pyrolysis. Following peeling, a curing and pyrolysis step 409 can be performed, where the film can be cut into sheets and vacuum dried using a two-stage method (100 to 140°C for 15 hours, followed by 200 to 240°C for 5 hours). The dried film can be heat-treated at 1000 to 1300°C to convert the polymer matrix into carbon. The pyrolysis step, by heating the anode to 400°C or higher, can produce an anode active material with a silicon content greater than or equal to 50% by weight.

[0054] In step 411, the pyrolyzed material can be flat-pressed or roll-pressed onto the collector, wherein a nominal loading of 0.35 to 0.75 mg / cm³ can be used. 2A polyamide-imide (applied as a 5 to 7 wt% varnish in NMP and vacuum dried at 100 to 140°C for 10 to 20 hours) is coated onto copper foil. In a flatbed lamination process, a heated hydraulic press (30 to 70 seconds, 250 to 350°C, and 3000 to 5000 psi) is used to laminate the silicon-carbon composite film onto the coated copper, thereby forming the final silicon composite electrode. In another embodiment, the pyrolyzed material can be roll-laminated onto the current collector.

[0055] In step 413, the electrodes can then be sandwiched together with the electrolyte using a separator and a cathode to form a battery. The battery can undergo a formation process that includes initial charging and discharging steps to lithium-ionize the anode, leaving some residual lithium.

[0056] In various embodiments according to this disclosure, a solid-state electrolyte optimized for alkaline-ion (e.g., lithium-ion) batteries and used to enhance the performance of such batteries can be used. Thus, adjustments can be made... Figure 4 The transfer lamination-based method described herein addresses the use of such electrolytes. For example, heat treatment of the solid composition can be added to and / or incorporated into this method.

[0057] Figure 5 An exemplary battery structure based on an exemplary solid-state electrolyte is illustrated according to an exemplary embodiment of the present disclosure. Figure 5 The image shows a battery structure 500 that includes a solid (polymer) electrolyte.

[0058] like Figure 5 As shown, the battery structure 500 includes an anode current collector 501, an anode 503, a polymer electrolyte 505, a cathode 507, and a cathode current collector 509. The battery structure 500 (and its components) may be similar to the battery 100 (and its similarly named components), as described above. Figure 1 In this regard, the anode current collector 501 may include a copper (Cu) based foil or sheet, the anode 503 may be a silicon-dominant anode, the cathode 507 may include a nickel-based cathode (e.g., a nickel-cobalt-aluminum oxide (NCA) based cathode), and the cathode current collector 509 may include an aluminum (Al) based foil or sheet. However, the battery structure 500 is combined and configured to use a polymer electrolyte instead of a liquid electrolyte.

[0059] As mentioned above, replacing the liquid electrolyte (or inorganic solid electrolyte) in lithium-ion batteries with an all-solid-state polymer electrolyte may be advantageous because such polymer electrolytes can overcome many problems and controversies that may arise from organic liquid electrolytes (e.g., leakage of organic solvents, flammability, etc.) and inorganic solid electrolytes (e.g., poor mechanical properties, low elastic modulus, high material, production, and processing costs, etc.). In this respect, in an ideal solvent-free polymer electrolyte, the lithium salt is dissolved and solvated by the polymer chains.

[0060] The polymer electrolyte used can be selected based on predetermined performance criteria. For example, the general requirements for solid polymer electrolytes can be: (i) high ionic conductivity, (ii) sufficient thermal and electrochemical stability, and (iii) excellent mechanical properties and dimensional stability. However, because polymers crystallize at room temperature, solvent-free polymer electrolytes rarely exhibit sufficiently high lithium conductivity at room temperature, which severely hinders the transport of Li ions.

[0061] In some cases, quasi-solid polymer or polymer gel electrolytes can be used (e.g., manufactured by immersing a certain amount of liquid electrolyte in a polymer solid membrane). For example, polyethylene oxide (PEO) is particularly suitable for solid polymer electrolytes, for instance, due to its ability to dissolve Li salts and its high ionic conductivity at high temperatures. However, PEO has relatively low mechanical strength, especially at elevated temperatures, which may limit battery performance.

[0062] An effective strategy for achieving a balance of desirable properties, including ionic conductivity, mechanical strength, thermal stability, and electrochemical window, in solid-state electrolytes for high performance is the use of polymer blends. This involves adaptively setting the constituent components and their ratios to optimize performance when using polymer mixtures. In this regard, direct blending of different types of polymers is convenient, efficient, low-cost, and easy to implement compared to other methods. Furthermore, the crystallinity of PEO can be reduced, for example, through hydrogen bonding between blended polymers, which can improve the ionic conductivity of the solid electrolyte. Polymer blends can also strengthen the PEO phase, further improving mechanical strength and dimensional thermal stability. Therefore, blending can be an effective method for improving the ionic conductivity and mechanical strength of PEO-based films.

[0063] The combination of solid-state electrolytes with lithium metal electrodes can be particularly advantageous because solid-state electrolytes can help prevent or potentially eliminate lithium dendrite growth problems that can occur in batteries using lithium metal foil as electrodes. While oxides and sulfides are generally considered better at preventing lithium dendrite growth than polymer electrolytes and other solid-state electrolytes, other high-energy-density electrodes (such as silicon, germanium, or other alloys) can also be used in batteries containing solid-state electrolytes. For example, polymer electrolytes are advantageous due to cost and manufacturing advantages when lithium deposition is not a concern.

[0064] In various exemplary embodiments, quaternary solid-state polymer electrolytes can be used. In this regard, exemplary quaternary solid-state polymer electrolytes can be manufactured using a mixture of polyethylene glycol (PEG) (a polyether compound), PEO (a long-chain, higher molecular weight form of PEG), a salt (e.g., a lithium salt, such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), a hydrophilic salt with the chemical formula LiC2F6NO4S2), and a thermal initiator (particularly a thermal initiator soluble in common organic solvents (e.g., azobisisobutyronitrile (AIBN)), which provides covalent bonds between the polymer (PEG and PEO) and the solvent, especially polar aprotic solvents with high chemical and thermal stability, such as ethylene glycol dimethyl ether (e.g., tetraethylene glycol dimethyl ether (TEGDME)). Heat treatment of such a quaternary composition results in the formation of an all-solid-state polymer that is flexible and mechanically stable.

[0065] For example, refer to Figure 5 The battery structure 500 shown may include, and / or be based on, a quaternary solid polymer composition, which can then be heat-treated to become a solid electrolyte within the battery (e.g., used as a separator). At this point, the polymer electrolyte may be in liquid form (e.g., at temperatures >70°C) prior to curing. Then, during manufacturing... Figure 5 The Si-anode-based battery shown uses a liquid polymer solution.

[0066] In various embodiments, the proportions of the various components in the solid-state quaternary composition can be adaptively selected and / or varied, for example, based on testing and experimentation, to achieve optimal performance. In this regard, various performance (including safety) criteria can be considered, thus allowing different compositions to be used for different batteries and / or different applications.

[0067] Figure 6 This is a graph illustrating the attenuated total reflectance (ATR) / Fourier transform infrared (FTIR) spectrum of an exemplary solid electrolyte according to an exemplary embodiment of the present disclosure. Figure 6Figure 601 illustrates the results of attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectral analysis of an exemplary polymer (e.g., a polymer having a PEG:PEO:LiTFSI:TEGDME:AIBN composition) according to this disclosure. Transmission spectroscopy can be used to determine the material properties of the polymer. For example, the positions of transmission peaks and valleys can indicate a specific composition.

[0068] Figure 7 This is a Nyquist plot illustrating an exemplary embodiment of a battery based on an exemplary solid-state electrolyte according to the present disclosure. Figure 7 Figure 701 shows the impedance analysis results of a solid-state battery implemented according to the present disclosure, for example, a battery including a solid electrolyte, such as a battery similar to... Figure 5 The battery 500 includes a Si-dominated anode, an NCA cathode, a common separator (e.g., a Celgard separator), and a solid electrolyte (e.g., using a PEG:PEO:LiTFSI:TEGDME:AIBN composition).

[0069] For example, impedance analysis can be based on electrochemical impedance spectroscopy (EIS) performed on a battery to study impedance at room temperature. Figure 7 The Nyquist plot illustrates the results of the impedance analysis. The plot shows that the battery exhibits good impedance performance and low resistance, indicating rapid migration of lithium ions throughout the anode, separator, and cathode.

[0070] Figure 8 This is a diagram illustrating the voltage distribution of a battery based on an exemplary solid-state electrolyte according to an exemplary embodiment of the present disclosure. Figure 8 Figures 801 and 803 illustrate the initial cycle voltage distribution of a solid-state battery implemented according to the present disclosure, for example, a battery including a solid electrolyte, such as a battery similar to... Figure 5 The battery 500 includes a Si-dominated anode, an NCA cathode, a common separator (e.g., a Celgard separator), and a solid electrolyte (e.g., using a PEG:PEO:LiTFSI:TEGDME:AIBN composition). The battery can, for example, be relative to Li... + / Li 0 Cycling was performed at 20°C with a C-rate of C / 50 between 4.2 V and 2.2 V. The expected battery capacity (803) is approximately 6.0 mAh. Figure 8 As shown, the use of a solid electrolyte allows the silicon anode cell to operate at room temperature with a first-cycle coulombic efficiency of >50% (801).

[0071] Figures 9 to 11Cyclic voltammetric responses of three different solid electrolytes with different compositions are shown, illustrating how the composition of the solid electrolyte can affect the stability of the battery's electrochemical voltage window.

[0072] Figure 9 Figure 901 illustrates the cyclic voltammetric response of an exemplary solid electrolyte according to an exemplary embodiment of the present disclosure. Figure 9 The diagram shown illustrates the cyclic volt-ampere response (current versus voltage) of an exemplary battery comprising a solid electrolyte formed using a composition of PEG:PEO:LiTFSI:TEGDME:AIBN in a ratio of 10.3:25.77:20.62:36.1:7.21, i.e., PEG is 10.3%, PEO is 25.77%, LiTFSI is 20.62%, TEGDME is 36.1%, and AIBN is 7.21%.

[0073] Figure 10 This is a graph illustrating the cyclic voltammetry response of another exemplary solid electrolyte according to an exemplary embodiment of the present disclosure. Figure 10 Figure 1001 illustrates the cyclic volt-ampere response (current versus voltage) of an exemplary battery comprising a solid electrolyte formed using a composition of PEG:PEO:LiTFSI:TEGDME:AIBN in a ratio of 10.53:26.32:21.05:36.84:5.26, i.e., PEG is 10.53%, PEO is 26.32%, LiTFSI is 21.05%, TEGDME is 36.84%, and AIBN is 5.26%.

[0074] Figure 11 This is a graph illustrating the cyclic voltammetry response of another exemplary solid electrolyte according to an exemplary embodiment of the present disclosure. Figure 11 Figure 1101 illustrates the cyclic volt-ampere response (current versus voltage) of an exemplary battery comprising a solid electrolyte formed using a composition of PEG:PEO:LiTFSI:TEGDME:AIBN in a ratio of 10.2:25.52:20.40:35.71:8.17, i.e., PEG is 10.2%, PEO is 25.52%, LiTFSI is 20.40%, TEGDME is 35.71%, and AIBN is 8.17%.

[0075] Therefore, in all three samples that underwent cyclic voltammetry testing, such as Figures 9 to 11In these studies, the ratio of PEG:PEO:LiTFSI:TEGDME in the composition (i.e., the relative proportions of these components to each other) remained constant, with only the amount of AIBN varying. The changes in the cyclic voltammetric responses shown in these figures suggest that AIBN may play a crucial role in the electrochemical stability of the solid polymer electrolyte, as increasing the proportion of AIBN in the composition increases the voltage at which oxidation occurs.

[0076] Therefore, the use of polymer blend-based composite all-solid-state electrolytes according to this disclosure, particularly in alkaline ion batteries (e.g., lithium-ion batteries, such as those with a Si-dominated anode), offers various advantages. For example, these all-solid-state electrolytes (and the batteries using them) are less prone to combustion, leakage, or corrosion compared to purely organic liquid electrolytes (and thus batteries). Additionally, high fracture energy and elastic modulus, along with excellent compatibility with the electrodes of these all-solid-state electrolytes, can be superior to purely inorganic electrolytes. Furthermore, polymer blend-based composite all-solid-state electrolytes can be chemically and mechanically more stable with electrodes (e.g., Si or graphite anodes and high-voltage Ni-rich (e.g., NCM or NCA) cathodes) and provide the function or role of a separator in the battery.

[0077] Other advantageous functional properties may include high thermal stability during charging and discharging, a wide electrochemical stability window for irreversible reactions, good compatibility with electrodes, enhanced Li mobility number, and high total Li. + Ionic conductivity. This can help address various safety concerns that may arise from using other electrolytes, and also offers several other significant advantages, such as higher energy storage capacity, ease of manufacture, and low cost. Another advantage of using the polymer blend-based composite all-solid-state electrolyte according to this disclosure is the ability to inject the electrolyte as a liquid, which allows for the continued use of existing equipment, designs, and manufacturing facilities, thereby enabling cost savings and rapid adoption.

[0078] Regarding its use in lithium-ion batteries, the quaternary solid polymer electrolyte according to this disclosure can provide benefits such as: increased safety (due to the absence of flammable liquid), increased energy density (which can be made possible by using a thin electrolyte / separator layer), increased thermal stability, minimized electrolyte degradation and consumption, reduced impedance (compared to typical solid electrolytes), reduced outgassing, high electrochemical stability over a wide voltage window, good mechanical strength and stability to accommodate electrode expansion and contraction, ease of fabrication into films of desired shapes and the ability to form good electrode / electrolyte contacts, inexpensive manufacturing and reuse of existing stationary equipment, etc.

[0079] An exemplary solid polymer electrolyte according to this disclosure may comprise a first polyether compound having a corresponding melting point (e.g., <100°C) and a corresponding molecular weight (e.g., <10,000 MW); a second polyether compound having a corresponding melting point (<100°C) and a corresponding molecular weight (e.g., >100,000 MW) higher than that of the first polyether compound; at least one lithium salt comprising a lithium cation and a basic anion; at least one glycol ether; and at least one thermal initiator. The solid polymer electrolyte may include a high-modulus oxide for reinforcing the solid polymer electrolyte. The high-modulus oxide may include one or more of Al₂O₃, Sb₂O₃, GeO₂, SiO₂, etc. The solid polymer electrolyte may include glass microfibers and / or an electrically insulating framework for reinforcing the solid polymer electrolyte.

[0080] The thermal initiator may include azobisisobutyronitrile (AIBN). The thermal initiator concentration may be >5% by weight; or, the thermal initiator concentration may be greater than 7% by weight; or, the thermal initiator concentration may be greater than 8% by weight. The first polyether compound may include polyethylene glycol (PEG). The second polyether compound may include polyethylene oxide (PEG). The lithium salt may include one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium hexafluorophosphate (LiPF6), and / or mixtures and combinations thereof. In some embodiments, the solid polymer electrolyte may contain two or more different lithium salts used as lithium sources (e.g., in the polymer electrolyte separator). The glycol ether may include one or more of monoethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and mixtures and combinations thereof. The glycol ether may include tetraethylene glycol dimethyl ether (TEGDME). The amount of the first polyether compound may be less than 15% of the solid polymer electrolyte. The amount of the second polyether compound can be 10% to 35% of the solid polymer electrolyte. The amount of lithium salt can be less than 25% of the solid polymer electrolyte. The amount of glycol ether can be less than 40% of the solid polymer electrolyte. The amount of thermal initiator can be less than 10% of the solid polymer electrolyte.

[0081] Exemplary electrochemical cells according to this disclosure may include a nonmetallic or metallic anode as the negative electrode, a cathode as the positive electrode, and a solid polymer electrolyte (e.g., as described above). The solid polymer electrolyte may be embedded and added to the positive electrode. The solid polymer electrolyte may be embedded and added to the negative electrode. The solid polymer electrolyte may be added to the battery in molten form. The anode may include a silicon-dominant (e.g., >50%) anode. In some embodiments, during the normal operating temperatures of the electrochemical cell (e.g., 0 to 35°C, 0 to 45°C, 0 to 55°C, or 0 to 60°C), the substantially liquid (e.g., molten) electrolyte may remain in substantially solid or gel form. In some embodiments, the electrochemical cell may be initially configured similarly to a normal electrochemical cell, i.e., having a liquid electrolyte including a standard separator, and then a solid polymer electrolyte may be added in molten form and then solidified. The electrochemical cell may incorporate designs in which lithium deposition is generally not a concern, such as graphite with metal oxides, silicon with metal oxides, or silicon-graphite composites with metal oxides.

[0082] As used herein, “and / or” means any one or more items in a list connected by “and / or”. As an example, “x and / or y” means any element in the three-element set {(x), (y), (x, y)}. In other words, “x and / or y” means “one or both of x and y”. As another example, “x, y and / or z” means any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and / or z” means “one or more of x, y and z”. As used herein, the term “exemplary” means used as a non-limiting instance, example, or illustration. As used herein, the terms “for example” and “eg” introduce a list of one or more non-limiting instances, examples, or illustrations.

[0083] As used herein, a device is “configured” to perform a function when it includes the hardware and code necessary to perform that function, if required, regardless of whether the performance of that function is disabled or not enabled (e.g., through user-configurable settings, factory tidiness, etc.).

[0084] Other embodiments of the invention may provide a non-transitory computer-readable medium and / or storage medium having stored thereon machine code and / or a computer program having at least one code segment executable by a machine and / or a computer, thereby enabling the machine and / or computer to perform the methods described herein.

[0085] Therefore, the invention can be implemented in hardware, software, or a combination of hardware and software according to various embodiments. The invention can be implemented centrally in at least one computing system, or distributed among several interconnected computing systems in a distributed manner. Any type of computing system or other device suitable for performing the methods described herein is appropriate. A typical combination of hardware and software can be a general-purpose computing system having programs or other code that, when loaded and executed, control the computing system to perform the methods described herein. Another typical implementation may include an application-specific integrated circuit (ASIC) or chip.

[0086] Various embodiments of the invention can also be embedded in a computer program product comprising all the features of the methods described herein and capable of implementing those methods when loaded into a computer system. As used herein, a computer program means any expression of a set of instructions in any language, code, or symbol intended to cause a system with information processing capabilities to perform a particular function directly or subsequently: a) be translated into another language, code, or symbol; or b) be reproduced in a different material form.

[0087] Although the invention has been described with reference to certain embodiments, those skilled in the art will understand that various changes and substitutions can be made without departing from the scope of the invention. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of the invention without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the specific embodiments disclosed, but rather to include all embodiments falling within the scope of the appended claims.

Claims

1. A solid polymer electrolyte, wherein the solid polymer electrolyte comprises: A first polyether compound having a corresponding first melting temperature; A second polyether compound having a corresponding second melting temperature, wherein the second melting temperature is higher than the first melting temperature; Lithium salts containing lithium cations and basic anions; and Diol ethers; as well as Thermal initiator, Wherein the second melting temperature is less than 100°C, and The thermal initiator includes azobisisobutyronitrile (AIBN) and the amount of the thermal initiator is greater than 8% by weight and less than 10% by weight of the solid polymer electrolyte.

2. The solid polymer electrolyte of claim 1, wherein the first polyether compound comprises polyethylene glycol (PEG).

3. The solid polymer electrolyte of claim 1, wherein the second polyether compound comprises polyethylene oxide (PEO).

4. The solid polymer electrolyte of claim 1, comprising a high-modulus oxide for enhancing the solid polymer electrolyte.

5. The solid polymer electrolyte of claim 4, wherein the high modulus oxide comprises one or more of Al2O3, Sb2O3, GeO2 and SiO2.

6. The solid polymer electrolyte of claim 1, comprising glass microfibers and / or an electrically insulating framework for reinforcing the solid polymer electrolyte.

7. The solid polymer electrolyte of claim 1, wherein the lithium salt comprises one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium hexafluorophosphate (LiPF6).

8. The solid polymer electrolyte of claim 1, wherein two or more lithium salts are used as lithium sources.

9. The solid polymer electrolyte of claim 1, wherein the glycol ether comprises one or more of monoethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

10. The solid polymer electrolyte of claim 1, wherein the glycol ether comprises tetraethylene glycol dimethyl ether (TEGDME).

11. The solid polymer electrolyte of claim 1, wherein the amount of the first polyether compound is less than 15% by weight of the solid polymer electrolyte.

12. The solid polymer electrolyte of claim 1, wherein the amount of the second polyether compound is from 10% to 35% by weight of the solid polymer electrolyte.

13. The solid polymer electrolyte of claim 1, wherein the amount of the lithium salt is less than 25% by weight of the solid polymer electrolyte.

14. The solid polymer electrolyte of claim 1, wherein the amount of the glycol ether is less than 40% by weight of the solid polymer electrolyte.

15. An electrochemical cell, said electrochemical cell comprising: Solid polymer electrolytes; A non-metallic or metallic anode configured as the negative electrode; as well as Cathode configured as positive electrode: The solid polymer electrolyte comprises: A first polyether compound having a corresponding first melting temperature; A second polyether compound having a corresponding second melting temperature, wherein the second melting temperature is higher than the first melting temperature; Lithium salts containing lithium cations and basic anions; and Diol ethers; and Thermal initiator, Wherein the second melting temperature is less than 100°C, and The thermal initiator includes azobisisobutyronitrile (AIBN) and the amount of the thermal initiator is greater than 8% by weight and less than 10% by weight of the solid polymer electrolyte.

16. The electrochemical battery of claim 15, wherein the solid polymer electrolyte is embedded and added to the positive electrode.

17. The electrochemical battery of claim 15, wherein the solid polymer electrolyte is embedded and added to the negative electrode.

18. The electrochemical cell of claim 15, wherein the solid polymer electrolyte is configured to be added to the electrochemical cell in a molten form.

19. The electrochemical cell of claim 18, wherein the solid polymer electrolyte is configured to be substantially solid or gel-like during the normal operating temperature of the electrochemical cell after being added to the electrochemical cell in a molten form.

20. The electrochemical cell of claim 18, wherein the electrochemical cell initially comprises a separator and a liquid electrolyte, and wherein the solid polymer electrolyte is then added in molten form and then solidified.

21. The electrochemical cell of claim 15, wherein the anode comprises a silicon-dominant anode.

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