High-performance solid electrolyte and battery based on polysiloxane si-tripodal ligand polymer and manufacturing method of high-performance solid electrolyte and battery

Abstract

Polymer electrolyte, in a first embodiment, a salt (SiPE) in a polymer electrolyte comprising a polysiloxane Si-tripodal ligand polymer, lithium bis (trifluoromethanesulfonyl) imide, and lithium tetrafluoroborate. In a second embodiment, a polymer (PiSE) in a salt electrolyte comprising a polysiloxane Si-tripodal ligand polymer, polyvinylidene fluoride, and lithium bis (trifluoromethanesulfonyl) imide. The polymer electrolyte may be formed as a self-supporting film. Various embodiments of the polymer electrolyte may be formed as a composite cathode, and may also be formed as a polymer electrolyte separator. A rechargeable battery cell includes a composite cathode as a positive electrode, a negative electrode, and a polymer electrolyte separator separating the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the polymer electrolyte separator are entirely solid.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 341,417, filed on May 12, 2022, which is incorporated herein by reference in its entirety. Background Art

[0003] The present disclosure relates to the field of electrochemical cells including electrolyte materials, electrodes, and other components used in electrochemical cells.

[0004] Solid-state lithium-ion batteries ("solid-state batteries") use solid electrolytes, as opposed to liquid electrolytes. Solid-state batteries may also use a combination of solid electrolytes with liquid electrolytes or other non-solid components. Solid-state batteries typically have a higher energy density than comparable lithium-ion batteries constructed with liquid electrolytes. Solid-state batteries are also inherently safer than lithium-ion batteries utilizing liquid electrolytes because solid electrolytes are not as flammable as liquid electrolytes. Polymers are highly suitable for making solid electrolytes due to their low flammability, processability, flexibility, structural stability, thermal stability, and wide electrochemical stability window. The present disclosure relates to polymer electrolytes and lithium-ion rechargeable battery cells having components based on polymer electrolytes.

[0005] Conventional polymer electrolytes utilize a polymer called polyethylene oxide (PEO) as a polymer host. PEO may be a polymer host for solid polymer electrolytes because it is economical, can be easily made into membranes, and has strong solvation properties for various lithiated salts. However, due to the semi-crystalline structure of the original PEO, polymer electrolytes based on PEO exhibit low ionic conductivity (10 -8 S / cm to 10 -6 S / cm), which is impractical for lithium-ion batteries.

[0006] In order to achieve the required ionic conductivity level, the operating temperature of the PEO-based polymer electrolyte must be increased to a temperature higher than the melting point of PEO (> 65 ° C), so that the semi-crystalline region becomes amorphous. This operating temperature requirement limits the practical application of the battery. Higher operating temperatures also create other problems because higher temperatures result in softer polymer films, which may increase the possibility of short circuits. Efforts to reduce the semi-crystalline regions of PEO at room temperature by adding plasticizers, solvents and other additives tend to produce films with poor mechanical strength and / or safety, and are not suitable for large-scale manufacturing. Polymer electrolytes prepared using other polymers such as polyacrylonitrile (PAN) and polyvinyl pyrrolidone (PVP) also have poor ionic conductivity.

[0007] The subject matter claimed herein is not limited to implementations that solve any disadvantages or operate only in environments such as those described above. Rather, this background is merely provided to illustrate an example technology in which some implementations described herein may be practiced. Summary of the invention

[0008] In one aspect of the present disclosure, a polymer electrolyte is provided, which includes a polysiloxane Si-tripod polymer ("PEST"), lithium bis(trifluoromethanesulfonyl)imide ("LiTFSI"), and lithium tetrafluoroborate ("LiBF4"). According to various embodiments, the polymer electrolyte can be composed of 70 wt% to 90 wt% PEST. According to other embodiments, the polymer electrolyte can also be composed of 8.0 wt% to 29.75 wt% LiTFSI. In still other embodiments, the polymer electrolyte is composed of 0.25 wt% to 2.0 wt% LiBF4. The ionic conductivity of the polymer electrolyte at a temperature greater than or equal to 25°C is 1×10 -5 S / cm or more. PEST, LiTFSI and LiBF4 can be formed into self-supporting films.

[0009] In another aspect of the present disclosure, a polymer electrolyte is provided, comprising a polysiloxane Si-tripod ligand polymer ("PEST"), polyvinylidene fluoride ("PVDF"), and lithium bis(trifluoromethanesulfonyl)imide ("LiTFSI"). In some embodiments, the PVDF is PVDF(534K). In still other embodiments, the PVDF is PVDF(700K). In still another embodiment, the PVDF is PVDF(HSV900). In embodiments where the PVDF is PVDF(534K), when the ratio of PVDF534K to LiTFSI is 50:50, the PEST concentration of the polymer electrolyte may be 5 wt % to 30 wt %; when the ratio is 40:60, the PEST concentration of the polymer electrolyte may be 5 wt % to 20 wt %; and when the ratio is 35:65, the PEST concentration of the polymer electrolyte may be 5 wt % to 10 wt %. In an embodiment where the PVDF is PVDF (700K), when the ratio of PVDF (700K) to LiTFSI is 50:50, the PEST concentration of the polymer electrolyte may be 5 wt % to 30 wt %; when the ratio is 40:60, the PEST concentration of the polymer electrolyte may be 5 wt % to 30 wt %; when the ratio is 35:65, the PEST concentration of the polymer electrolyte may be 5 wt % to 20 wt %. In an embodiment where the PVDF is PVDF (HSV900), when the ratio of PVDF (HSV900) to LiTFSI is 50:50, the PEST concentration of the polymer electrolyte may be 5 wt % to 30 wt %; when the ratio is 40:60, the PEST concentration of the polymer electrolyte may be 5 wt % to 25 wt %; when the ratio is 35:65, the PEST concentration of the polymer electrolyte may be 5 wt % to 20 wt %. The ionic conductivity of the polymer electrolyte at a temperature greater than or equal to 25° C. is 1×10 -5 S / cm or more. PEST, PVDF and LiTFSI can be formed into self-supporting films.

[0010] Another aspect of the present disclosure relates to a method of making a polymer electrolyte according to an embodiment of the present disclosure. PEST is dissolved in a first organic solvent. LiTFSI is dissolved in a second organic solvent. LiBF4 is also dissolved in the second organic solvent. The second organic solvent containing LiTFSI and LiBF4 is added to the first organic solvent containing PEST to obtain a mixture, and the mixture is heated and mixed until it is homogeneous.

[0011] Yet another aspect of the present disclosure relates to a method of making a polymer electrolyte according to another embodiment of the present disclosure. PEST is dissolved in a first organic solvent. LiTFSI is dissolved in a second organic solvent. PVDF is added to the second organic solvent containing LiTFSI. The second organic solvent containing PVDF and LiTFSI is then added to the first organic solvent containing PEST to obtain a mixture, which is heated and mixed until it is homogeneous.

[0012] Another aspect of the present disclosure provides a composite cathode comprising various embodiments of a polymer electrolyte as described above mixed with a cathode active material, carbon black and a polyvinylidene fluoride binder and formed as a cathode film on a current collector. In this aspect of the present disclosure, the polymer electrolyte acts as a cathode electrolyte in the composite cathode. In one embodiment, the cathode active material can be lithium iron phosphate. In other embodiments, lithium nickel manganese cobalt oxide (NMC) in which more than 50% of the nickel manganese cobalt oxide is nickel.

[0013] Another aspect of the present disclosure provides for manufacturing a composite cathode. A polymer electrolyte according to various embodiments as described above is prepared. The polymer electrolyte is mixed with a cathode active material, a carbonaceous material, and a polyvinylidene fluoride binder that binds the cathode active material, the carbonaceous material, and the polymer electrolyte; the cathode active material, the carbonaceous material, the polyvinylidene fluoride binder, and the polymer electrolyte are then formed into a cathode film; and the cathode film is then formed on a current collector. In some embodiments, the cathode film layer and the current collector are calendered to increase the density of the cathode film layer to 1.7 g / cm 3 .

[0014] One aspect of the present disclosure also provides a method for making a polymer electrolyte separator. A polymer electrolyte according to various embodiments as described above is prepared. The polymer electrolyte is then cast onto a composite cathode made using the above method. The polymer electrolyte separator can also be formed separately and then combined with the composite cathode by dry placement.

[0015] Another aspect of the present disclosure relates to an electrode sub-stack, which includes a composite cathode and a polymer electrolyte separator each having various embodiments of a polymer electrolyte as described above. The electrode sub-stack also includes an anode layer formed on a negative current collector to form an anode. The anode, the polymer electrolyte separator and the composite cathode together form an electrode sub-stack.

[0016] Another aspect of the present disclosure provides a rechargeable battery cell having: a composite cathode including a cathode layer formed on a first current collector, wherein the composite cathode is according to various embodiments of the polymer electrolyte as described above; an anode layer, the anode layer is formed on a second current collector to form a negative electrode, wherein the anode layer is lithium metal; a polymer electrolyte separator according to various embodiments of the polymer electrolyte as described above, the polymer electrolyte separator separating the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the polymer electrolyte separator are solid. In some embodiments, the rechargeable battery cell does not contain any liquid electrolyte.

[0017] These and other aspects are further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure ("Fig.") 1 is a flow chart showing steps for preparing a polymer electrolyte and preparing a composite cathode based on a polymer electrolyte according to one embodiment of the present disclosure.

[0019] Figure 2A is a perspective view showing preparation of a polymer electrolyte mixture according to one embodiment of the present disclosure.

[0020] Figure 2B is a perspective view showing preparation of a slurry mixture to form a composite cathode according to one embodiment of the present disclosure.

[0021] Figure 2C is a perspective view showing solution casting and knife coating of a slurry mixture to form a composite cathode according to one embodiment of the present disclosure.

[0022] Figure 2D is a side view showing solution casting and knife coating of a slurry mixture to form a composite cathode according to one embodiment of the present disclosure.

[0023] Figure 2E Shown is the slurry mixture on a composite cathode after knife coating according to one embodiment of the present disclosure.

[0024] Figure 2F Shown is the calendering of a composite cathode according to one embodiment of the present disclosure.

[0025] Figure 2G is a perspective view showing solution casting of a polymer electrolyte separator using a polymer electrolyte according to one embodiment of the present disclosure.

[0026] Figure 2His a side view showing a knife coating of a solution cast polymer electrolyte separator according to one embodiment of the present disclosure.

[0027] Figure 3A A rechargeable battery cell according to one embodiment of the present disclosure is shown.

[0028] Figure 3B An example of a cross-sectional structure of a rechargeable battery cell according to an embodiment of the present disclosure is shown.

[0029] Figure 3C An example of a perspective view of a rechargeable battery cell according to an embodiment of the present disclosure is shown.

[0030] Figure 4A is a perspective view showing a polymer electrolyte according to one embodiment of the present disclosure.

[0031] Figure 4B is a perspective view showing a polymer electrolyte according to one embodiment of the present disclosure.

[0032] Figure 4C is a perspective view showing a polymer electrolyte according to one embodiment of the present disclosure.

[0033] Figure 4D is a perspective view showing a polymer electrolyte according to one embodiment of the present disclosure.

[0034] Figure 4E is a perspective view showing a polymer electrolyte according to one embodiment of the present disclosure.

[0035] Figure 5 Graph showing linear sweep voltammetry (LSV) measurements of salts in a polymer electrolyte having a PEST concentration of 80 wt %, a LiTFSI concentration of 18 wt %, and a LiBF 4 concentration of 2 wt % according to one embodiment of the present disclosure.

[0036] Figure 6 is a graph showing linear sweep voltammetry (LSV) measurements of salts in a polymer electrolyte wherein the PEST concentration is 80 wt %, the LiTFSI concentration is 19.75 wt %, and the LiBF 4 concentration is 0.25 wt % according to another embodiment of the present disclosure.

[0037] Like reference numerals are used to describe like parts throughout the figures of the drawings. DETAILED DESCRIPTION

[0038] The present disclosure is presented to enable one of ordinary skill in the art to make and use the inventions set forth herein, and to incorporate these inventions into the context of specific applications. Various modifications and various uses in different applications will be apparent to those skilled in the art, and the general principles defined herein may be applied to a wide range of embodiments. Therefore, the present disclosure is not intended to be limited to the embodiments presented, but rather to the widest range consistent with the principles and new features disclosed herein.

[0039] Polymer electrolytes are feasible as cathode electrolytes and polymer electrolyte separators in solid and semi-solid lithium ion rechargeable batteries. For a technically and commercially viable polymer electrolyte, it must show sufficient ionic conductivity. Polysiloxane Si-tripod ligand polymers, lithium salts (e.g., lithium bis(trifluoromethanesulfonyl)imide and / or lithium tetrafluoroborate) and polyvinylidene fluoride formed as polymer electrolytes according to the embodiments of this article exceed the threshold ionic conductivity over a wide temperature range (including at 25°C). In addition, the polymer electrolytes of the present disclosure can be easily manufactured into self-supporting films, thereby further enhancing their technical and commercial feasibility as separators between cathodes and anodes. As self-supporting films, the polymer electrolytes of the present disclosure can be relatively easily manufactured by solution casting and dry placement without applying high pressure to the electrolyte material during the manufacturing process. When manufactured on a large scale, polymer electrolytes that can form self-supporting films have significant advantages in roll-to-roll automated manufacturing processes. The quantitative composition of the polymer electrolyte that delivers the required ionic conductivity while still forming a self-supporting film is determined by testing. The composite cathode and separator were assembled into rechargeable lithium-ion coin cells and tested and measured.

[0040] Ionic conductivity

[0041] Ionic conductivity is a property parameter of polymer electrolytes that describes the movement of ions through the polymer matrix and controls the performance of lithium-ion batteries. Low ionic conductivity levels may lead to poor battery performance. Low ionic conductivity levels indicate high crystallinity within the polymer electrolyte. At room temperature, ionic conductivity values ​​>1×10 -3 S / cm is highly desirable and highly unusual for polymer electrolytes. For reference purposes, conventional carbonate-based liquid electrolytes with standard polypropylene (PP) separators achieve approximately 8×10 -4 S / cm ionic conductivity. At room temperature, it exhibits an ionic conductivity greater than 10 -4 Dry polymer electrolytes with ionic conductivity of 1000 S / cm are considered highly desirable, as exceeding this threshold generally implies successful room temperature operation at acceptable C-rates (≥0.1C). However, this does not necessarily mean that the electrolyte exhibits ionic conductivity below 1×10 -4Polymer electrolytes with ionic conductivity of 0.1 S / cm are obsolete.

[0042] Depending on the polymer electrolyte, slightly applied heat can increase the ionic conductivity to levels suitable for successful operation at higher C-rates. For example, at room temperature, 1 × 10 -5 The polymer electrolyte can exhibit an ionic conductivity greater than 1×10 S / cm at temperatures above 50°C. -4 For applications where a heat source is available or heat is generated as the battery pack and the entire device operate, such as electric vehicles, it is recommended to have an ionic conductivity of less than 10 S / cm. -4 S / cm would be of great commercial interest. Thus, ionic conductivity values ​​at room temperature are greater than 1×10 -5 Dry polymer electrolytes with 200 S / cm are technically and commercially feasible.

[0043] The ionic conductivity in the working examples of the present disclosure described below was tested using electrochemical impedance spectroscopy in a temperature range of 25° C. to 80° C. The frequency range was 100 MHz to 1 MHz, and the AC amplitude was 10 mV. The ionic conductivity (σ) was calculated using the following equation:

[0044] Equation (1):

[0045]

[0046] In equation (1), t is the thickness of the polymer electrolyte, A is the area of ​​the stainless steel electrode, and R is the volume resistance (determined by EIS (electrochemical impedance spectroscopy)).

[0047] A technically and commercially viable polymer electrolyte for a rechargeable battery must not only meet the required ionic conductivity, but it must also form a self-supporting film such as those according to the embodiments of the present disclosure described herein. The self-supporting film has the mechanical properties required to function as a composite cathode or separator in a solid-state battery cell. The self-supporting film is not gel-like. It is also not viscous and it is non-flowable. When standardized forces and pressures are applied, it is flexible but maintains its xy dimensions. As a self-supporting film, it also exists in a form that does not require an additional substrate to provide structural support.

[0048] The self-supporting film can be formed into large membranous sheets that can be manufactured on a large scale in automated equipment and processed into rolls. This brings significant advantages to the manufacture of complete lithium-ion batteries in a roll-to-roll process. The self-supporting film that can be manufactured into large membranous sheets can also be easily cut into suitable sizes and / or shapes for incorporation into rechargeable lithium-ion batteries.

[0049] The self-supporting film can also be incorporated into a rechargeable battery cell along with other components such as the cathode and anode without applying additional pressure or other methods to adhere the film to the substrate. The polymer electrolyte separator, which is a self-supporting film, can be bonded to the cathode layer by dry placement, even though the polymer electrolyte separator can also be bonded by solution casting.

[0050] Comb polymers (particularly polysiloxanes) have excellent properties for forming polymer electrolytes. Polysiloxanes have a low glass transition temperature Tg, which causes increased ionic conductivity. Polysiloxanes are safe because they are inherently non-flammable, non-toxic and non-flammable. In addition, polysiloxanes have high oxidation capacity, which means that polysiloxanes are voltage-stable. This is because polysiloxanes have an inorganic skeleton. Typically, polysiloxanes can exhibit a voltage of more than 5V due to their inorganic skeleton. Polysiloxanes are still highly customizable through grafting. Finally, polysiloxanes are highly stable when used in combination with lithium metal anodes. Polysiloxanes also have some properties that can be further improved. The silicon skeleton of polysiloxanes is insulating, and polysiloxanes also exhibit poor dissolution of lithium cations. The electrochemical properties of polysiloxanes can be greatly improved by grafting.

[0051] Polysiloxane Si-tripod ligand polymers ("PESTs") are formed by modifying polysiloxane polymers by grafting electroactive organic polyether chains. PESTs are viscous gels and, when lithiated and dispersed in organic solvents, experience high ionic conductivity (>10 -4 S / cm). The synthesized PEST has the structure shown in the figure below:

[0052]

[0053] The process used to synthesize PEST is partially shown in the figure below:

[0054]

[0055] In the first example of synthesizing PEST, 5 grams of polymethylhydrogensiloxane (PMHS) were measured in a 50 ml round bottom flask. A magnetic stirring bar was prepared. After placing PMHS under a nitrogen stream, 5 ml of benzene was added via a syringe. The reaction was bubbled with nitrogen for 15 minutes. A vinyl si-tripod ligand was added via a syringe, and the reaction was bubbled with nitrogen for another 30 minutes. 0.001 ml of Karstedt catalyst (2% in xylene) was added. Bubbling was observed. The reaction was further bubbled for 20 minutes, sealed with paraffin film, and placed in an oil bath at 50 ° C for three days. The magnetic stirring bar was removed. Benzene was also removed under reduced pressure. The resulting product was a gel with a light gray color.

[0056] In the second example of synthesizing PEST, 2.5 grams of polymethylhydrogensiloxane (PMHS) and 10.5 ml of vinyl si-tripod ligand were measured in a 25 ml round-bottom flask. A magnetic stirring bar was prepared. The magnetic stirring bar was also equipped with a drying tube to reduce the moisture in the reaction system. 2.5 ml of benzene was added via a syringe. The reaction was bubbled with nitrogen for 15 minutes. Vinyl si-tripod ligand was added via a syringe. 0.001 ml of Karstedt catalyst (2% in xylene) was added, and the mixture was placed in an oil bath at 50 ° C. The reaction was monitored daily with 1H NMR for four days. At 20 hours, there was still resonance from vinyl. On the 2nd day, there was still some vinyl remaining, so another 0.001 mL of Karstedt catalyst was added. On the 3rd day, there was still some vinyl remaining, so 0.246 g of PMHS was added. On the 4th day, all vinyl was removed. Remove the magnetic stirring bar and drying tube. Remove benzene under reduced pressure. The result was a colorless transparent gel.

[0057] A lithium salt or combination of lithium salts is added to PEST to formulate a polymer electrolyte. Different lithium salts can be combined with PEST to achieve the desired ionic conductivity of the polymer electrolyte. LiTFSI and LiBF4 can increase ionic conductivity. LiTFSI and LiBF4 can also be used to produce mechanically stable films.

[0058] Electrochemical stability window (ESW) is another important parameter that determines whether polymer electrolytes can be practically used in Li-ion batteries. The charge and discharge characteristics of the electrode material are within a specific voltage range, and the polymer electrolyte needs to be stable within this voltage range. If not, the polymer electrolyte will undergo side reactions and therefore cannot maintain normal battery operation. The maximum voltage of cathode materials such as lithium iron phosphate ("LFP"), NMC622 and NMC811 is less than 4.3V. Nickel manganese cobalt oxide cathode materials with nickel, manganese and cobalt contents of 60%, 20% and 20%, respectively, are generally referred to as NMC622. Nickel manganese cobalt oxide cathode materials with nickel, manganese and cobalt contents of 80%, 10% and 10%, respectively, are generally referred to as NMC811. However, battery chemistry consisting of a Li metal anode exhibits a higher charge window and may increase to greater than 4.5V. Therefore, a polymer electrolyte that can work from 0V to 5V relative to Li / Li+ would be ideal. Early polymer electrolytes based on PEO could not exceed 4V, thus limiting cathode selection to LFP. ESW stable up to 4.7 V may be acceptable for LFP and NMC cathodes.

[0059] The ESW of the polymer electrolyte was determined using linear sweep voltammetry (LSV) measurement. The ESW was determined by observing the flat region between the two main peaks of the linear sweep voltammetry (LSV) measurement.

[0060] Salt Embodiments in Polymer Electrolytes

[0061] One embodiment of the present disclosure is a salt in polymer electrolyte (SiPE) embodiment. SiPE comprises PEST and a dilithium salt as a polymer host. At least the first lithium salt is a perfluorinated lithium salt including lithium bis(fluorosulfonyl)imide ("LiFSI"), lithium bis(pentafluoroethanesulfonyl)imide ("LiBETI"), and lithium bis(trifluoromethanesulfonyl)imide ("LiTFSI"). The second lithium salt is LiBF4. In a preferred embodiment, the dilithium salt is LiTFSI and LiBF4.

[0062] SiPE is mostly composed of polymer PEST, and a small amount is composed of dilithium salt. Its composition can be expressed as:

[0063] y(PEST)+z(a·LiTFSI+b·LiBF4)

[0064] Y, z, a and b are concentrations in weight percent. Y can be in the range of 70 wt % to 90 wt %, and z can be in the range of 10 wt % to 30 wt %. LiTFSI concentration a can be in the range of 8.0 wt % to 29.75 wt %. LiBF4 concentration b can be in the range of 0.25 wt % to 3.0 wt %. These concentration ranges are determined by testing.

[0065] In SiPE, the amount of PEST, LiTFSI and LiBF4 must be controlled to achieve the desired ionic conductivity while forming a self-supporting film. In general, PEST, LiTFSI and LiBF4 have the following effects on the formation of polymer electrolyte films:

[0066]

[0067] LiBF4 allows the formation of mechanically stable self-supporting films. As explained above, PEST is a viscous gel at room temperature. The addition of LiBF4 allows the gel to form a solid. But too much LiBF4 hinders the formation of a self-supporting film. The BF4- anion in LiBF4 has a small atomic volume. Due to this, it can be trapped in the ethylene oxide chains of the PEST polymer. This causes the resulting polymer electrolyte film to harden. Therefore, excessive LiBF4 may cause the polymer electrolyte film to become extremely brittle, hard and non-flexible.

[0068] Furthermore, LiBF4 is generally not ionically conductive like other fluoride-based lithium salts such as LiTFSI. Therefore, in order to increase sufficient ionic conductivity, LiTFSI is added. The TFSI- anion is stabilized by strong electron-withdrawing groups and lone nitrogen atoms. LiTFSI also dissociates well in low dielectric constant solvents, leading to higher dissociation and increased ionic conductivity. At the same time, the larger anion size reduces the glass transition temperature of the polymer electrolyte and has a negative impact on the formation of solid films. Therefore, excess levels of LiTFSI prevent the formation of self-supporting films.

[0069] Polymer Embodiments in Salt Electrolytes

[0070] A second embodiment of the present disclosure is a polymer in salt electrolyte (PiSE). The PiSE comprises PEST mixed with polyvinylidene fluoride (PVDF) and perfluorinated lithium salts including LiFSI, LiBETI and LiTFSI. In one embodiment, the PVDF is PVDF (534K). In another embodiment, the PVDF is PVDF (700K). In yet another embodiment, the PVDF is PVDF (HSV900).

[0071] PiSE is mostly composed of PVDF and lithium salt mixture and a small amount of PEST. Its composition can be expressed as:

[0072] y(a·PVDF:b·LiTFSI)+z(PEST)

[0073] Here, y and z are concentrations in weight percent, and a:b is a ratio. y is in the range of 70 wt % to 95 wt %, and z is in the range of 5 wt % to 30 wt %. The a:b ratio can vary between 50:50 and 35:65.

[0074] Preparation of polymer electrolyte solution and composite cathode

[0075] Next, we will discuss Figure 1 and FIG. 2A to FIG. 2H An example of preparing a polymer electrolyte and a composite cathode according to an embodiment of the present disclosure is described.

[0076] Figure 11 is a flow chart showing steps for preparing a polymer electrolyte and preparing a composite cathode based on a polymer electrolyte according to one embodiment of the present disclosure. In step 1, a polymer electrolyte mixture is prepared. In step 2, the polymer electrolyte is mixed with a cathode active material and other components to form a slurry. In step 3, the slurry is mixed. In step 4, the slurry solution is cast onto a current collector to form a composite cathode film. In step 5, the solution-cast composite cathode film is calendered.

[0077] Figure 2A is a perspective view showing the preparation of a polymer electrolyte. This corresponds to Figure 1 Step 1. In a first container, the polymer PEST is dissolved in an organic solvent such as acetonitrile, N-methyl-2-pyrrolidone (NMP) or cyclohexanone. The PEST mixture is heated and stirred to promote the dissolution of PEST in the organic solvent.

[0078] In the SiPE embodiment, the first lithium salt LiTFSI and the second lithium salt LiBF4 are dissolved in an organic solvent to form a dilithium salt mixture. The dilithium salt mixture is then added to the PEST mixture. All components are mixed under hot conditions until a uniform mixture is obtained. According to various embodiments of the present disclosure, the concentrations of the added LiTFSI, LiBF4, and PEST are expressed as weight percentages (wt%) of the added LiTFSI, LiBF4, and PEST.

[0079] In the PiSE embodiment, the lithium salt LiTFSI is dissolved in an organic solvent to form a lithium salt mixture. Polyvinylidene fluoride (PVDF) is then added to the lithium salt mixture. The lithium salt and PVDF mixture is then added to the PEST mixture. All components are mixed under hot conditions until a uniform mixture is obtained. According to various embodiments of the present disclosure, the concentrations of the added LiTFSI, PVDF, and PEST are expressed as weight percentages (wt %) of the added LiTFSI, PVDF, and PEST.

[0080] Figure 2B is a perspective view showing preparation of a slurry mixture for forming a polymer electrolyte composite cathode. Figure 2B Corresponds to Figure 1Steps 2 and 3 of the present invention. The cathode active material, carbon black, polyvinylidene fluoride (PVDF) binder and polymer electrolyte mixture are mixed in a container to form a slurry 110. 70% cathode active material, 10% by weight carbon black, 15% by weight polymer electrolyte and 5% by weight PVDF can be used in the slurry mixture. The slurry is transferred to a conditioning mixer (e.g., Thinky ARE-250) and mixed at a certain revolutions per minute (RPM) for several minutes until the mixture is uniform. The polymer electrolyte acts as a cathode electrolyte in the composite cathode.

[0081] Figure 2C is a perspective view showing solution casting and knife coating of the slurry mixture to form a composite cathode. This corresponds to Figure 1 Step 4. The slurry 110 is poured onto a 16 μm thick current collector 120 with an applicator 150. Suitable current collectors include aluminum current collectors, although copper-based current collectors such as copper foil can be used. The organic solvent (NMP in this example) is evaporated until a dense, dry and black film remains. Although the organic solvent can be removed by evaporation, the removal of the solvent is not limited to evaporation. Other methods of removing the solvent include distillation, filtration, extraction, crystallization, centrifugation and adsorption. A scraper 140 is then applied to the poured slurry mixture to flatten the slurry mixture 110 onto the current collector 120, thereby producing a composite cathode film 130 ( Figure 2E ). The scraper 140 should be a wet blade of appropriate thickness. Figure 2D is a diagram showing solution casting and knife coating of a slurry mixture 110 to form a composite cathode film 130 ( Figure 2E ) is a side view of a slurry mixture 110. A scraper 140 is moved across the solution cast slurry mixture 110 to flatten the slurry mixture. Figure 2E is a side view showing the slurry mixture 110 on the current collector 120 after being doctored to form the cathode film 130. The composite cathode film was then heated to 60°C to remove any residual solvent in the slurry mixture.

[0082] Figure 2F The calendering of the composite cathode film is shown. This corresponds to Figure 1 Step 5. The composite cathode film 130 and the current collector 120 are fed through a set of rollers 160. The rollers 160 rotate together in their respective directions as shown by the arrows to introduce the composite cathode film 130 and the current collector 120 and apply a compressive force to calender the cathode film 130 and the current collector 120. The cathode film 130 is calendered to increase its density to 1.7 g / cm 3 .

[0083] Preparation of polymer electrolyte separators

[0084] Next, we will discuss Figure 2G and Figure 2H An example of a polymer electrolyte separator formed using the polymer electrolyte of the present disclosure will be described.

[0085] Figure 2G 1 is a perspective view showing solution casting of a polymer electrolyte separator using a polymer electrolyte according to one embodiment of the present disclosure. The polymer electrolyte mixture 110 solution is cast onto the substrate as described above with reference to FIG. Figure 2F The formed composite cathode film 130 is coated with the mixture 110. One example of an applicator is a dropper, but any device by which a small amount of the mixture 110 can be applied to the composite cathode 100 and then dispersed can be used. Figure 2H 1 is a side view showing the doctor blade coating of a solution-cast polymer electrolyte separator according to one embodiment of the present disclosure. After the mixture 110 is cast onto the formed composite cathode film 130, a doctor blade 140 is used to spread the mixture 110 to form a uniform layer over the entire surface of the composite cathode film 130. The organic solvent in the mixture 110 is evaporated to form a polymer electrolyte layer 170. When formed in this manner, the polymer electrolyte layer 170 is fused with the composite cathode film 130 and is not displaced or separated.

[0086] The solution casting method for casting polymer electrolytes as separators according to the embodiments of the present disclosure described herein has several benefits. First, the electrode-electrolyte interface impedance is very low, such as between the electrode and the polymer electrolyte. This is because the polymer electrolyte is in direct contact with the electrode. This is independent of whether the electrode onto which the polymer electrolyte solution is cast is the cathode or the anode. The polymer electrolyte directly cast onto the cathode can exhibit better electrochemical performance at higher C-rates. Secondly, it is a scalable and cost-effective method for incorporating polymer electrolyte membranes into solid-state batteries. However, the polymer electrolyte separator of the present disclosure can also be cast onto a separate substrate, peeled off, and then dried and placed onto the composite cathode membrane.

[0087] The solution casting of polymer electrolytes as separators is not limited to forming a single polymer electrolyte layer. The solution casting process can be repeated multiple times to form a separator comprising multiple polymer electrolyte separator layers. Depending on the overall cell design, multiple polymer electrolyte layers can be formed to produce separators of 100 μm or larger, thereby improving the performance of the separator function to prevent the separator from being penetrated by dendrites.

[0088] The polymer electrolyte and the polymer electrolyte separator present in the composite cathode that function as the cathode electrolyte have the same ionic conductivity. Although the polymer electrolyte separator is formulated with the same polymer electrolyte embodiment as used in the composite cathode, the polymer electrolyte separator is not limited to the same embodiment and can be formulated with polymer electrolytes of different embodiments in the present disclosure.

[0089] Lithium-ion rechargeable battery

[0090] Next, we will discuss FIG. 3A to FIG. 3C Examples of rechargeable battery cells using a composite cathode and a polymer electrolyte separator according to embodiments of the present disclosure are described.

[0091] Figure 3A A rechargeable battery cell 200 according to an embodiment of the present disclosure is shown. The cell 200 includes a cathode current collector 201, a composite cathode film 202, an anode current collector 204, and an anode active material layer 205. The composite cathode film 202 and the cathode current collector 201 together form a composite cathode 203. The anode active material layer 205 and the anode current collector 204 together form an anode 206. A polymer electrolyte separator 207 separates the composite cathode 203 from the anode 206. In one example, the composite cathode 203 is cut to a size of 50 mm×34 mm, and the anode 206 is cut to a size of 49 mm×33 mm. The composite cathode 203 is intentionally cut so that it is larger than the anode 206 to prevent internal short circuits caused by contact between the cathode and the anode.

[0092] exist Figure 3A In the embodiment, the cathode current collector 201 and the anode current collector 204 also serve as terminals for electrical contact with external parts. For this reason, the cathode current collector 201 and the anode current collector 204 may be arranged to be partially exposed to the outside of the external body 209. Alternatively, the cathode current collector 201 or the anode current collector 204 may be combined with each other by ultrasonic welding, and the lead electrode may be exposed to the outside of the external body 209 instead of the positive current collector 201 and the negative current collector 204.

[0093] In some embodiments, a non-conductive insert is added at each end of the stack of rechargeable battery cells. Figure 3A and Figure 3B The non-conductive insert increases the mechanical rigidity of the stack. A polyolefin film (not shown) may also be tightly wrapped around the stack to ensure that the components of the stack do not move and maintain interfacial contact with each other.

[0094] As the external body 209 of the rechargeable battery cell 200, for example, a laminated film having a multi-layer structure can be used, in which a highly flexible metal film of aluminum, stainless steel, copper, nickel, etc. is arranged above a film formed of a material such as polyethylene, polypropylene, polycarbonate, ionomer or polyamide, and an insulating synthetic resin film of polyamide-based resin, polyester-based resin, etc. is arranged above the metal film serving as the outer surface of the external body.

[0095] Figure 3B 2 shows an example of a cross-sectional structure of a rechargeable battery cell 200. Although for simplicity, Figure 3A An example including only two current collectors is shown, but an actual battery includes a plurality of electrode stacks. Figure 3B The example in 200 includes 16 electrode layers. The rechargeable battery cell 200 has flexibility even though it includes 16 electrode layers. Figure 3B A structure including 8 layers of anode current collector 204 and 8 layers of cathode current collector 201 (ie, 16 layers in total) is shown. Figure 3B A cross section of the lead portion of the negative electrode is shown, and 8 anode current collectors 204 are bonded to each other by ultrasonic welding, but the number of electrode layers is not limited to 16, and may be more than 16 or less than 16. In the case of a large number of electrode layers, the rechargeable battery cell may have a higher capacity. In contrast, in the case of a small number of electrode layers, the rechargeable battery may be thinner and have greater flexibility.

[0096] Figure 3C An example of a perspective view of a rechargeable battery cell 200 is shown. Figure 3C As shown, nickel tab 210 is welded to composite cathode 203, and nickel tab 211 is also welded to anode 206. The welded portions and inner / outer tab portions may be covered with Kapton tape (not shown) to prevent short circuits.

[0097] Summary of Examples 1-1 to 1-32 (Variant #1 SiPE)

[0098] In the following Examples 1-1 to 1-32, a series of polymer electrolyte compositions having different amounts of PEST, LiTFSI, and LiBF4 were formulated into polymer electrolyte composite cathodes and polymer electrolyte separators and tested according to various embodiments of the present disclosure.

[0099] Examples 1-1 and 1-2

[0100] In Examples 1-1 and 1-2, a polymer electrolyte is prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. In a first container, PEST is dissolved in an organic solvent, NMP. The PEST mixture is heated and stirred to promote the dissolution of PEST in the organic solvent. The first lithium salt LiTFSI and the second lithium salt LiBF4 are dissolved in an organic solvent to form a double lithium salt mixture. The double lithium salt mixture is then added to the PEST mixture. The PEST, LiTFSI and LiBF4 mixture is then mixed under hot conditions until all components are evenly distributed. In Example 1-1, the PEST concentration in the example is 90.0% by weight, the LiTFSI concentration is 9.9% by weight, and the LiBF4 concentration is 0.1% by weight. In Example 1-2, the PEST concentration in the example is 90.0% by weight, the LiTFSI concentration is 9.875% by weight, and the LiBF4 concentration is 0.125% by weight.

[0101] In both Examples 1-1 and 1-2, attempts were made to form a composite cathode according to the method of preparing a polymer electrolyte composite cathode of the present disclosure. An attempt was also made to form a polymer electrolyte separator layer using the method of preparing a solid polymer electrolyte separator of the present disclosure.

[0102] In both Examples 1-1 and 1-2, the polymer electrolyte failed to form a mechanically stable composite cathode and a mechanically stable polymer electrolyte separator film. The formed film was sticky, difficult to peel, and easily tore, similar to Figure 4B The ionic conductivity of the film cannot be measured.

[0103] Examples 1-3

[0104] In Examples 1-3, a polymer electrolyte was prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. In a first container, PEST was dissolved in an organic solvent, NMP. The PEST mixture was heated and stirred to promote the dissolution of PEST in the organic solvent. A first lithium salt, LiTFSI, and a second lithium salt, LiBF4, were dissolved in an organic solvent to form a double lithium salt mixture. The double lithium salt mixture was then added to the PEST mixture. The PEST, LiTFSI, and LiBF4 mixture was then mixed under hot conditions until all components were evenly distributed. The PEST concentration in the example was 90 wt %, the LiTFSI concentration was 9.75 wt %, and the LiBF4 concentration was 0.25 wt %.

[0105] A slurry mixture is prepared according to the method for preparing a slurry mixture for a polymer electrolyte composite cathode of the present disclosure. A cathode active material, carbon black, and a polyvinylidene fluoride binder are mixed with a polymer electrolyte mixture to form a slurry mixture. The slurry is cast onto an aluminum current collector. The organic solvent NMP is evaporated until a dense, dry, and black film is left. A scraper is then used to flatten the cast slurry mixture onto the current collector to form a cathode film. The cathode film is successfully formed. The cathode film is then calendered to form a composite cathode.

[0106] The method of preparing a solid polymer electrolyte separator using a polymer electrolyte of the present disclosure is used to prepare a polymer electrolyte separator layer. The polymer electrolyte mixture is poured through a dropper solution. After the polymer electrolyte solution is poured, a film applicator such as a doctor blade is used to spread the mixture to form a layer. The organic solvent in the polymer electrolyte mixture is removed by evaporation over time. A layer having a similar Figure 4D Characteristics of free-standing thin films in polymer electrolyte separator membranes.

[0107] The ionic conductivity of the polymer electrolyte separator membrane was measured at 25° C., 50° C., and 80° C. The polymer electrolyte separator exhibited the following ionic conductivity: 0.0846×10 -3 S / cm, at 50°C: 0.205×10 -3 S / cm, and 0.388×10 -3 S / cm.

[0108] Examples 1-4

[0109] In Examples 1-4, polymer electrolytes were prepared using the method of the present disclosure for preparing polymer electrolyte mixtures. The PEST concentration in the examples was 90 wt %, the LiTFSI concentration was 9.5 wt %, and the LiBF4 concentration was 0.5 wt %. Composite cathodes and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. Cathode films were successfully formed and calendered to form composite cathodes. Polymer electrolyte separator films were also successfully formed, similar to Figure 4D The polymer electrolyte separator exhibited the following ionic conductivity: 0.123×10 -3 S / cm, at 50°C: 0.268×10 -3 S / cm, and 0.512×10 -3 S / cm.

[0110] Examples 1-5

[0111] In Examples 1-5, polymer electrolytes were prepared using the method of the present disclosure for preparing polymer electrolyte mixtures. The PEST concentration in the examples was 90 wt %, the LiTFSI concentration was 9.0 wt %, and the LiBF4 concentration was 1.0 wt %. Composite cathodes and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. Cathode films were successfully formed and calendered to form composite cathodes. Polymer electrolyte separator films were also successfully formed, similar to Figure 4D The polymer electrolyte separator exhibited the following ionic conductivity: 0.0379×10 -3 S / cm, at 50°C: 0.0848×10 -3 S / cm, and 0.139×10 -3 S / cm.

[0112] Examples 1-6

[0113] In Examples 1-6, polymer electrolytes were prepared using the method of the present disclosure for preparing polymer electrolyte mixtures. The PEST concentration in the examples was 90 wt %, the LiTFSI concentration was 8.0 wt %, and the LiBF4 concentration was 2.0 wt %. Composite cathodes and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. Cathode films were successfully formed and calendered to form composite cathodes. Polymer electrolyte separator films were also successfully formed, similar to Figure 4D The polymer electrolyte separator exhibited the following ionic conductivity: 0.424×10 -3 S / cm, 0.100×10 at 50°C -3 S / cm, and 0.209×10 -3 S / cm.

[0114] Examples 1-7, 1-8 and 1-9

[0115] In Examples 1-7, 1-8 and 1-9, a polymer electrolyte is prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. In a first container, PEST is dissolved in an organic solvent, NMP. The PEST mixture is heated and stirred to promote the dissolution of PEST in the organic solvent. The first lithium salt LiTFSI and the second lithium salt LiBF4 are dissolved in an organic solvent to form a double lithium salt mixture. The double lithium salt mixture is then added to the PEST mixture. The PEST, LiTFSI and LiBF4 mixture are then mixed under hot conditions until all components are evenly distributed. In Example 1-7, the PEST concentration in the example is 90.0% by weight, the LiTFSI concentration is 7.0% by weight, and the LiBF4 concentration is 3.0% by weight. In Example 1-8, the PEST concentration in the example is 90.0% by weight, the LiTFSI concentration is 5.0% by weight, and the LiBF4 concentration is 5.0% by weight. In Examples 1-9, the PEST concentration in the examples was 90.0 wt %, the LiTFSI concentration was 1.0 wt %, and the LiBF 4 concentration was 9.0 wt %.

[0116] In all three examples, attempts were made to form a composite cathode according to the method of making a polymer electrolyte composite cathode of the present disclosure.An attempt was also made to form a polymer electrolyte separator layer using the method of making a solid polymer electrolyte separator of the present disclosure.

[0117] In all three examples, the polymer electrolyte failed to form a mechanically stable composite cathode and a mechanically stable polymer electrolyte separator film. The formed film was brittle, hard and inflexible, similar to Figure 4A The ionic conductivity of the film cannot be measured.

[0118] Examples 1-10 and 1-11

[0119] Compared with Examples 1-1 to 1-9, starting from Example 1-10, followed by Example 1-11, the concentration of PEST was reduced to 80 wt %. The polymer electrolyte was prepared using the same method as in Examples 1-1 to 1-9. In Example 1-10, the PEST concentration in the example was 80.0 wt %, the LiTFSI concentration was 19.9 wt %, and the LiBF4 concentration was 0.1 wt %. In Example 1-11, the PEST concentration in the example was 80.0 wt %, the LiTFSI concentration was 19.875 wt %, and the LiBF4 concentration was 0.125 wt %.

[0120] In two examples, attempts were made to form a composite cathode according to the method of making a polymer electrolyte composite cathode of the present disclosure.An attempt was also made to form a polymer electrolyte separator layer using the method of making a solid polymer electrolyte separator of the present disclosure.

[0121] In both examples, the polymer electrolytes failed to form mechanically stable composite cathodes and mechanically stable polymer electrolyte separator films. The films formed were sticky, difficult to peel, and easily tore, similar to Figure 4B The ionic conductivity of the film cannot be measured.

[0122] Examples 1-12 to 1-15

[0123] In Examples 1-12 to 1-15, the concentration of PEST was 80 wt %. The polymer electrolyte was prepared using the same method as Examples 1-1 to 1-9. In Example 1-12, the LiBF4 concentration was increased from 0.125 wt % in Example 1-11 to 0.25 wt %, while the LiTFSI concentration was reduced to 19.75 wt %. Then, in Examples 1-13, 1-14 and 1-15, the LiBF4 concentration was further increased to 0.5 wt %, 1.0 wt % and 2.0 wt %, respectively, while in Examples 1-13, 1-14 and 1-15, the LiTFSI concentration was reduced to 19.5 wt %, 19.0 wt % and 18.0 wt %, respectively. In all four examples, the composite cathode and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. In all four examples, cathode films were successfully formed and calendered to form composite cathodes. In all four examples, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In all four examples, the polymer electrolyte separator membranes exhibited a thermal conductivity higher than 1.0×10 -5 S / cm threshold ionic conductivity.

[0124] Examples 1-16 and 1-17

[0125] In Examples 1-16 and 1-17, the concentration of PEST was also reduced to 80 wt % compared to Examples 1-7 and 1-8, but with the same concentration of LiBF4 of 3 wt % and 5 wt %, respectively. And like Examples 1-7 and 1-8, attempts were made to form a composite cathode and polymer electrolyte separator. The polymer electrolyte failed to form a mechanically stable composite cathode and mechanically stable polymer electrolyte separator film. The film formed was brittle, hard and non-flexible, similar to Figure 4A The ionic conductivity of the film cannot be measured.

[0126] Examples 1-19

[0127] Example 1-19 is a repeat test with a LiBF4 concentration of 0.125 wt % like Examples 1-2 and 1-11, but in which PEST is reduced to a concentration of 70 wt %, and LiTFSI is correspondingly increased to 29.875 wt %. Similar to Examples 1-2 and 1-11, the polymer electrolyte failed to form a mechanically stable composite cathode and a mechanically stable polymer electrolyte separator film. The film formed was sticky, difficult to peel, and easily tore, similar to Figure 4B The ionic conductivity of the film cannot be measured.

[0128] Examples 1-20 to 1-23

[0129] In Examples 1-20 to 1-23, the concentration of PEST was reduced to 70 wt % compared to Examples 1-3 to 1-6 and Examples 1-12 to 1-15 at 90 wt % and 80 wt % levels, respectively. The polymer electrolyte was prepared using the same method. The LiBF4 concentration was set to the same amount as the comparative examples in Examples 1-3 to 1-6 and Examples 1-12 to 1-15, and the LiTFSI concentration was adjusted accordingly at each level to maintain the total weight % of the dilithium salt. In all four examples, the composite cathode and polymer electrolyte separator layer were prepared using the preparation method of the present disclosure. In all four examples, the cathode film was successfully formed and calendered to form the composite cathode. In all four examples, the polymer electrolyte separator film was also successfully formed, similar to Figure 4D In all four examples, the films showed a relative humidity higher than 1.0×10 -5 S / cm threshold ionic conductivity.

[0130] Examples 1-24

[0131] In Examples 1-24, the concentration of PEST was set to 70 wt %. The concentration of LiBF4 was set to 3.0 wt %, and the concentration of LiTFSI was set to 27.0 wt %. Composite cathode and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. The cathode film was successfully formed and calendered to form a composite cathode. A polymer electrolyte separator film was also successfully formed, similar to Figure 4D At the measurement temperatures of 25℃, 50℃ and 80℃, the films showed a -5 S / cm threshold ionic conductivity.

[0132] Examples 1-25

[0133] In Examples 1-25, the PEST concentration was reduced to 70.0 wt%. The LiBF4 concentration was set to 4.0 wt%, and the LiTFSI concentration was set to 26.0 wt%. An attempt was made to form a composite cathode and polymer electrolyte separator. The polymer electrolyte failed to form a mechanically stable composite cathode and mechanically stable polymer electrolyte separator film. The film formed was brittle, hard and non-flexible, similar to Figure 4A The ionic conductivity of the film cannot be measured.

[0134] Examples 1-26

[0135] In Example 1-26, the PEST concentration was reduced to 70.0 wt % compared to Example 1-8 at the 90 wt % level and Example 1-17 at the 80 wt % level. However, the LiBF4 concentration was the same at 5 wt %. The LiTFSI concentration was adjusted accordingly at the 90 wt % and 80 wt % levels to maintain the total wt % of the dilithium salt. Like Example 1-8 and Example 1-17, attempts were made to form a composite cathode and polymer electrolyte separator. The polymer electrolyte failed to form a mechanically stable composite cathode and mechanically stable polymer electrolyte separator film. The film formed was brittle, hard and non-flexible, similar to Figure 4A The ionic conductivity of the film cannot be measured.

[0136] Examples 1-27 to 1-32

[0137] In Examples 1-27 to 1-32, the LiBF4 concentration levels of Examples 1-19 to 1-23 and 1-25 were repeated, but the PEST concentration was reduced to 60.0 wt %. The LiTFSI concentration was increased accordingly. In all Examples, attempts were made to form a composite cathode and polymer electrolyte separator. The polymer electrolyte failed to form a mechanically stable composite cathode and mechanically stable polymer electrolyte separator film. The film that was formed was dimensionally unstable and wet, similar to Figure 4C The ionic conductivity of the film cannot be measured.

[0138] Table 1: Summary of Working Examples 1-1 to 1-32

[0139]

[0140]

[0141] Through Examples 1-1 and 1-2, it was initially determined that a LiBF4 concentration of at least 0.25 wt% was required to form a self-supporting film. When the LiBF4 concentration is below 0.25 wt%, the SiPE polymer electrolyte will cause the film to be sticky, difficult to peel and easy to tear. This is because when the LiBF4 is too low, there is too much LiTFSI. The larger anion size of LiTFSI reduces the glass transition temperature of the SiPE polymer electrolyte and is not conducive to promoting the formation of a solid film. Examples 1-10 and 1-11 at 80 wt% PEST levels and Example 1-19 at 70 wt% PEST levels further determined that the minimum LiBF4 concentration is 0.25 wt%.

[0142] Examples 1-6 and 1-15 show that LiBF4 cannot exceed 2.0 wt% at 90 wt% and 80 wt% PEST, respectively. Example 1-24 shows that LiBF4 cannot exceed 3.0 wt%. Above 2 wt% LiBF4 at 90 wt% and 80 wt% PEST, and above 3 wt% LiBF4 at 70 wt% PEST, will not form a self-supporting film, and the film formed will be brittle, hard and non-flexible, similar to Figure 4A film shown.

[0143] Examples 1-1 to 1-9 show that the concentration of PEST cannot exceed 90 wt%. This is because a concentration of at least 10 wt% must be retained for the dilithium salts LiTFSI and LiBF4, both of which need to satisfy 1.0×10 - 5 S / cm. Compared with Examples 1-12 to 1-15 and Examples 1-20 to 1-23 at 80 wt % and 70 wt % PEST levels, respectively, Examples 1-3 to 1-6 with the lowest level of LiTFSI exhibited a threshold level of ionic conductivity of only just meeting 1.0×10 -5 S / cm at 25°C. Therefore, Examples 1-3 to 1-6 determined that the lithium salt concentration cannot be lower than 10 wt%, below which the threshold ionic conductivity cannot be met. Therefore, the maximum PEST concentration is 90 wt%.

[0144] Examples 1-27 to 1-32 show that the PEST concentration cannot be less than 70 wt%. The main function of PEST is to provide a matrix for dissociating the lithium salt, and secondly to assist the transport of lithium ions through the active oxirane group side chains. However, when the PEST concentration drops below a certain level, the polymer becomes wet and mechanically fails and cannot dissociate the lithium salt. Examples 1-27 to 1-32 determine that at 60 wt% PEST and lower, no self-supporting film is formed under any combination of LiTFSI and LiBF4. Therefore, the minimum concentration of PEST is 70 wt%.

[0145] Summary of PVDF (534K) of Examples 2-1 to 2-21

[0146] In the following Examples 2-1 to 2-21, a series of polymer electrolyte compositions having different amounts of PVDF (534K), LiTFSI, and PEST were formulated into polymer electrolyte composite cathodes and polymer electrolyte separators and tested according to various embodiments of the present disclosure.

[0147] Examples 2-1 to 2-7

[0148] In Examples 2-1 to 2-7, a polymer electrolyte is prepared according to a method for preparing a PiSE electrolyte with PVDF (534K) according to the present disclosure. In the PiSE electrolyte, the a:b ratio is maintained at a 50:50 ratio, where a is PVDF (534K) and b is LiTFSI. In the embodiment, the parts of y and z are changed, where y is PVDF (534K) and LiTFSI and z is PEST. In Example 2-1, y is 95 wt %, and z is 5 wt %. In Example 2-2, y is reduced to 90 wt %, and z is increased to 10 wt %. In Example 2-3, y is reduced to 85 wt %, and z is increased to 15 wt %. In Example 2-4, y is reduced to 80 wt %, and z is increased to 20 wt %. In Example 2-5, y is reduced to 75 wt %, and z is increased to 25 wt %. In Example 2-6, y is reduced to 70 wt %, and z is increased to 30 wt %. In Example 2-7, y was decreased to 65 wt %, and z was increased to 35 wt %.

[0149] Composite cathode and polymer electrolyte separator layers were prepared using the preparation method of the present disclosure. In Examples 2-1 to 2-6, cathode films were successfully formed and calendered to form composite cathodes. In Examples 2-1 to 2-6, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 2-7, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivities of the films in Examples 2-1 to 2-6 at 25°C, 50°C, and 80°C were measured and reported in Table 2. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0150] Examples 2-8 to 2-13

[0151] In Examples 2-8 to 2-13, like the previous examples in the Example 2 series, the polymer electrolytes were prepared according to the method of preparing PiSE electrolytes with PVDF (534K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 40:60 ratio, where a was PVDF (534K) and b was LiTFSI. In the examples, the portions of y and z were changed, where y was PVDF (534K) and LiTFSI and z was PEST. In Example 2-8, like Example 2-1, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until in Example 2-13, y was 70 wt% and z was 30 wt%.

[0152] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 2-8 to 2-11, cathode films were successfully formed and calendered to form composite cathodes. In Examples 2-8 to 2-11, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 2-12 and 2-13, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivity of the films in Examples 2-8 to 2-11 at 25°C, 50°C, and 80°C was measured and reported in Table 2. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0153] Examples 2-14 to 2-17

[0154] In Examples 2-14 to 2-17, like the previous examples in the Example 2 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (534K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 35:65 ratio, where a was PVDF (534K) and b was LiTFSI. In the examples, the portions of y and z were changed, where y was PVDF (534K) and LiTFSI and z was PEST. In Example 2-14, like Examples 2-1 and 2-8, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until y was 80 wt% and z was 20 wt% in Example 2-17.

[0155] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 2-14 and 2-15, cathode films were successfully formed and calendered to form composite cathodes. In Examples 2-14 and 2-15, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 2-16 and 2-17, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivity of the films in Examples 2-14 and 2-15 at 25°C, 50°C, and 80°C was measured and reported in Table 2. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0156] Examples 2-18 to 2-21

[0157] In Examples 2-18 to 2-21, like the previous examples in the Example 2 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (534K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 30:70 ratio, where a was PVDF (534K) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (534K) and LiTFSI and z was PEST. In Example 2-14, like Examples 2-1 and 2-8, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until y was 80 wt% and z was 20 wt% in Example 2-17.

[0158] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In all four Examples 2-18 to 2-21, cathode films and polymer electrolyte separators were successfully formed. The formed films were wet, similar to Figure 4E The film in.

[0159] Table 2: Summary of working examples 2-1 to 2-21

[0160]

[0161]

[0162] Through Examples 2-1 to 2-21, the composition of PEST, PVDF (534K) and LiTFSI for forming a self-supporting film was determined. First, the a:b ratio was fixed to 50:50. From this, y and z were first set to 95 wt % and 5 wt %, respectively. Y gradually decreases (which is equivalent to an increase in z PEST), and the resulting polymer electrolyte will not be mechanically stable and wet. After determining the boundary conditions of the a:b ratio (the range in which the mechanical stability of the polymer electrolyte is stable), the a:b ratio will be adjusted to increase the lithium salt (reduce the PVDF content). At higher LiTFSI concentrations (b), the range of the optimal y:z ratio is limited because the polymer electrolyte matrix cannot be dissociated due to the lack of a polymer host. When the a:b formula reaches 30:70, the polymer host content becomes so low that the lithium salt cannot be effectively dissociated, and no matter how the concentration of PEST is, it is impossible to form a self-supporting film.

[0163] In Examples 2-1 to 2-7, the ratio of PVDF (534K) to LiTFSI is 50:50, which is changed to 40:60 in Examples 2-8 to 2-13, 35:65 in Examples 2-14 to 2-17, and 30:70 in Examples 2-18 to 2-21. As the PEST concentration increases, the film will eventually fail to form a self-supporting film because it is too wet. The amount of PEST in the case where a self-supporting film cannot be formed at each PVDF (534K) to LiTFSI ratio is determined. In Example 2-7, for a ratio of 50:50, at a PEST concentration of 35 wt%, a self-supporting film cannot be formed. In Example 2-12, for a ratio of 40:60, at a PEST concentration of 25 wt%, a self-supporting film cannot be formed. In Example 2-16, for a ratio of 35:65, at a PEST concentration of 15 wt%, a self-supporting film cannot be formed. In Examples 2-18 to 2-21, it is impossible to form a self-supporting film at any concentration of PEST, confirming that the ratio of PVDF (534K) to LiTFSI cannot be lower than 35:65.

[0164] Summary of Examples 3-1 to 3-24 PVDF (700K)

[0165] In Examples 3-1 to 3-24 described below, a series of polymer electrolyte compositions having different amounts of PVDF (700K), LiTFSI, and PEST were formulated into polymer electrolyte composite cathodes and polymer electrolyte separators and tested according to various embodiments of the present disclosure.

[0166] Examples 3-1 to 3-7

[0167] In Examples 3-1 to 3-7, polymer electrolytes are prepared according to the method for preparing PiSE electrolytes with PVDF (700K) according to the present disclosure. In the PiSE electrolyte, the a:b ratio is maintained at a 50:50 ratio, where a is PVDF (700K) and b is LiTFSI. The parts of y and z are changed in the embodiment, where y is PVDF (700K) and LiTFSI and z is PEST. In Example 3-1, y is 95 wt % and z is 5 wt %. In Example 3-2, y is reduced to 90 wt % and z is increased to 10 wt %. In Example 3-3, y is reduced to 85 wt % and z is increased to 15 wt %. In Example 3-4, y is reduced to 80 wt % and z is increased to 20 wt %. In Example 3-5, y is reduced to 75 wt % and z is increased to 25 wt %. In Example 3-6, y is reduced to 70 wt % and z is increased to 30 wt %. In Example 3-7, y was reduced to 65 wt % and z was increased to 35 wt %.

[0168] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 3-1 to 3-6, cathode films were successfully formed and calendered to form composite cathodes. In Examples 3-1 to 3-6, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 3-7, the cathode membrane and the polymer electrolyte separator were not successfully formed. The membrane formed was wet, similar to Figure 4E The ionic conductivities of the membranes in Examples 3-1 to 3-6 at 25°C, 50°C, and 80°C were measured and reported in Table 3. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0169] Examples 3-8 to 3-14

[0170] In Examples 3-8 to 3-14, like the previous examples in the Example 3 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (700K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 40:60 ratio, where a was PVDF (700K) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (700K) and LiTFSI and z was PEST. In Example 3-8, like Example 3-1, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until y was 65 wt% and z was 35 wt% in Example 3-14.

[0171] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 3-8 to 3-13, cathode films were successfully formed and calendered to form composite cathodes. In Examples 3-8 to 3-13, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 3-14, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivities of the membranes in Examples 3-8 to 3-13 at 25°C, 50°C, and 80°C were measured and reported in Table 3. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0172] Examples 3-15 to 3-20

[0173] In Examples 3-15 to 3-20, like the previous examples in the Example 3 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (700K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 35:65 ratio, where a was PVDF (700K) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (700K) and LiTFSI and z was PEST. In Example 3-15, like Examples 3-1 and 3-8, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until y was 70 wt% and z was 30 wt% in Example 3-20.

[0174] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 3-15 to 3-18, cathode films were successfully formed and calendered to form composite cathodes. In Examples 3-15 to 3-18, polymer electrolyte separator films were also successfully formed, similar to Figure 4DIn Examples 3-19 and 3-20, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivities of the membranes in Examples 3-15 to 3-18 at 25°C, 50°C, and 80°C were measured and reported in Table 3. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0175] Examples 3-21 to 3-24

[0176] In Examples 3-21 to 3-24, like the previous examples in the Example 3 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (700K) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 30:70 ratio, where a was PVDF (700K) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (534K) and LiTFSI and z was PEST. In Example 3-21, like Examples 3-1, 3-8 and 3-15, y was 95 wt% and z was 5 wt%. These concentrations changed similarly until y was 80 wt% and z was 20 wt% in Example 3-24.

[0177] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In all four Examples 3-21 to 3-24, the cathode film and polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The film in.

[0178] Table 3: Summary of Working Examples 3-1 to 3-24

[0179]

[0180]

[0181] Through Examples 3-1 to 3-24, the compositions of PEST, PVDF (700K) and LiTFSI for forming free-standing thin films were determined.The same general testing procedure used for the 2 series of examples to determine the boundary conditions for using PVDF (534K) for PiSE was repeated.

[0182] In Examples 3-1 to 3-7, the ratio of PVDF (700K) to LiTFSI is 50:50, which is changed to 40:60 in Examples 3-8 to 3-14, 35:65 in Examples 3-15 to 3-20, and 30:70 in Examples 3-21 to 3-24. As the PEST concentration increases, it will eventually fail to form a self-supporting film because the film is too wet. The amount of PEST in the case where a self-supporting film cannot be formed at each PVDF (700K) to LiTFSI ratio is determined. In Example 3-7, for a ratio of 50:50, at a PEST concentration of 35 wt%, a self-supporting film cannot be formed. In Example 3-14, for a ratio of 40:60, at a PEST concentration of 35 wt%, a self-supporting film cannot be formed. In Example 3-19, for a ratio of 35:65, at a PEST concentration of 25 wt%, a self-supporting film cannot be formed. In Examples 3-21 to 3-24, it is impossible to form a self-supporting film at any concentration of PEST, confirming that the ratio of PVDF (700K) to LiTFSI cannot be lower than 35:65.

[0183] Summary of Examples 4-1 to 4-22 PVDF (HSV900)

[0184] In Examples 4-1 to 4-22 described below, a series of polymer electrolyte compositions having different amounts of PVDF (HSV900), LiTFSI, and PEST were formulated into polymer electrolyte composite cathodes and polymer electrolyte separators and tested according to various embodiments of the present disclosure.

[0185] Examples 4-1 to 4-7

[0186] In Examples 4-1 to 4-7, polymer electrolytes were prepared according to the method for preparing PiSE electrolytes with PVDF (HSV900) according to the present disclosure. In the PiSE electrolyte, the a:b ratio was maintained at a ratio of 50:50, where a was PVDF (HSV900) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (HSV900) and LiTFSI and z was PEST. In Example 4-1, y was 95 wt % and z was 5 wt %. In Example 4-2, y was reduced to 90 wt % and z was increased to 10 wt %. In Example 4-3, y was reduced to 85 wt % and z was increased to 15 wt %. In Example 4-4, y was reduced to 80 wt % and z was increased to 20 wt %. In Example 4-5, y was reduced to 75 wt % and z was increased to 25 wt %. In Example 4-6, y was reduced to 70 wt % and z was increased to 30 wt %. In Examples 4-7, y was reduced to 65 wt % and z was increased to 35 wt %.

[0187] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 4-1 to 4-6, cathode films were successfully formed and calendered to form composite cathodes. In Examples 4-1 to 4-6, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Example 4-7, the cathode film and the polymer electrolyte separator were not successfully formed. The ionic conductivity of the membranes in Examples 4-1 to 4-6 at 25°C, 50°C and 80°C was measured and reported in Table 4. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0188] Examples 4-8 to 4-14

[0189] In Examples 4-8 to 4-14, like the previous examples in the Example 4 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (HSV900) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 40:60 ratio, where a was PVDF (HSV900) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (700K) and LiTFSI and z was PEST. In Example 4-8, like Example 4-1, y was 95 wt% and z was 5 wt%. These concentrations were changed similarly until y was 65 wt% and z was 35 wt% in Example 4-14.

[0190] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 4-8 to 4-12, cathode films were successfully formed and calendered to form composite cathodes. In Examples 4-8 to 4-12, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 4-13 and 4-14, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivities of the membranes in Examples 4-8 to 4-12 at 25°C, 50°C, and 80°C were measured and reported in Table 4 below. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0191] Examples 4-15 to 4-20

[0192] In Examples 4-15 to 4-20, as in the previous examples in the Example 4 series, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (HSV900) according to the present disclosure. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 35:65 ratio, where a was PVDF (HSV900) and b was LiTFSI. The portions of y and z were changed in the examples, where y was PVDF (HSV900) and LiTFSI and z was PEST. In Example 4-15, as in Examples 4-1 and 4-8, y was 95 wt % and z was 5 wt %. These concentrations were changed similarly until y was 70 wt % and z was 30 wt % in Example 4-20.

[0193] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 4-15 to 4-18, cathode films were successfully formed and calendered to form composite cathodes. In Examples 4-15 to 4-18, polymer electrolyte separator films were also successfully formed, similar to Figure 4D In Examples 4-19 and 4-20, the cathode membrane and the polymer electrolyte separator were not successfully formed. The formed film was wet, similar to Figure 4E The ionic conductivities of the membranes in Examples 4-15 to 4-18 at 25°C, 50°C, and 80°C were measured and reported in Table 4. All exceeded 1.0×10 -5 The threshold ionic conductivity is S / cm.

[0194] Examples 4-21 to 4-22

[0195] In Examples 4-21 and 4-22, the polymer electrolyte was prepared according to the method of preparing PiSE electrolytes with PVDF (HSV900) according to the present disclosure, as in the previous examples in the Example 4 series. In these examples of PiSE electrolytes, the a:b ratio was maintained at a 30:70 ratio, where a was PVDF (HSV900) and b was LiTFSI. In Example 4-21, y was 95 wt% and z was 5 wt%. In Example 4-22, y was 90 wt% and z was 10 wt%.

[0196] Composite cathode and polymer electrolyte separator layers were prepared using the preparation methods of the present disclosure. In Examples 4-21 and 4-22, the cathode film and polymer electrolyte separator were not successfully formed. The film formed was wet, similar to Figure 4E The envelope in.

[0197] Table 4: Summary of Working Examples 4-1 to 4-22

[0198]

[0199]

[0200] Through Examples 4-1 to 4-22, the compositions of PEST, PVDF (HSV900) and LiTFSI for forming self-supporting films were determined. For PVDF (HSV900), the same general test procedure used for Series 2 and 3 to determine the boundary conditions for PiSE using PVDF (534K) and PVDF (700K) was also repeated.

[0201] In Examples 4-1 to 4-7, the ratio of PVDF (HSV900) to LiTFSI was 50:50, which was changed to 40:60 in Examples 4-8 to 4-14, 35:65 in Examples 4-15 to 4-20, and 30:70 in Examples 4-21 to 4-22. As the PEST concentration increased, the quality of the film eventually failed to form a self-supporting film because it became too wet. The amount of PEST in the case where a self-supporting film could not be formed at each PVDF (HSV900) to LiTFSI ratio was determined. In Example 4-7, for a ratio of 50:50, at a PEST concentration of 35 wt%, a self-supporting film could not be formed. In Example 4-13, for a ratio of 40:60, at a PEST concentration of 30 wt%, a self-supporting film could not be formed. In Example 4-19, for a ratio of 35:65, at a PEST concentration of 25 wt%, a self-supporting film could not be formed. In Examples 4-21 to 4-22, it was impossible to form a self-supporting film at any concentration of PEST, confirming that the ratio of PVDF (HSV900) to LiTFSI could not be lower than 35:65.

[0202] Example 5-1 (LFP and SiPE variant #1)

[0203] In Example 5-1, a SiPE mixture was prepared using the method for preparing a SiPE polymer electrolyte mixture of the present disclosure. PEST was used as a polymer, and LiTFSI and LiBF4 were used as dilithium salts. The concentration of PEST was 80 wt %, the concentration of LiTFSI was 18 wt %, and the concentration of LiBF4 was 2 wt %.

[0204] Slurry and composite cathodes were also prepared according to the method for preparing a slurry mixture of a polymer electrolyte composite cathode of the present disclosure. The cathode active material for the composite cathode is lithium iron phosphate (LFP). A polymer electrolyte mixture was also prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. The polymer electrolyte separator was then dissolved in acetonitrile (AN), and its solution was cast on a previously formed LFP-based composite cathode. AN was evaporated by placing the film in a small pre-combustion chamber in a glove box and causing a slight vacuum. The process was repeated twice to ensure that a dense and uniform film was deposited on the LFP-based composite cathode. Thereafter, a thick Li metal (500 μm) was placed on top and assembled into a coin cell together with the LFP composite cathode having a formed polymer electrolyte layer. The diameter of the LFP composite cathode, polymer electrolyte layer, and lithium metal stack was 16 mm.

[0205] Figure 5 The measured linear sweep voltammetry (LSV) of the polymer electrolyte and its ESW are shown. The flat area between the two main peaks (leftmost and rightmost) indicates a voltage window of 4.8 V as calculated at the point where the tangent lines intersect.

[0206] Example 5-2 (LFP with SiPE variant #1 and dry placement)

[0207] In Example 5-1, the steps for preparing the slurry mixture and the composite cathode are repeated. Like Example 5-1, PEST is used as the polymer, and LiTFSI and LiBF4 are used as dilithium salts. Like Example 5-1, the cathode active material for the composite cathode is lithium iron phosphate (LFP). Like Example 5-1, the polymer electrolyte mixture is also prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. The concentration of PEST is 80% by weight, the concentration of LiTFSI is 19.5% by weight, and the concentration of LiBF4 is 0.5% by weight. Unlike Example 5-1, the polymer electrolyte is then poured into a Teflon evaporating dish and the solvent is evaporated. After evaporation, a polymer electrolyte self-supporting film is formed, peeled from the dish, and formed into a circular disk for coin cells with a diameter of 16 mm. The circular disk is then placed dry on the composite cathode. Then a thick Li metal (500 μm) is placed on top of the circular disk. Finally, the composite cathode, polymer electrolyte separator layer and lithium metal anode layer are assembled into a coin cell. Another identical coin cell is manufactured similarly.

[0208] Figure 6The measured linear sweep voltammetry (LSV) of the polymer electrolyte and its ESW are shown. The flat area between the two main peaks (leftmost and rightmost) indicates that the voltage window is 5.0 V as calculated at the point where the tangent lines intersect.

[0209] Pre-Example 5-3 (LFP and PiSE variant #2)

[0210] In Example 5-3, a PiSE mixture was prepared using the method for preparing a PiSE polymer electrolyte mixture of the present disclosure. PEST was used as a polymer, PVDF (534K) as a PVDF, and LiTFSI as a lithium salt. The ratio of PVDF (534K) to LiTFSI was 35:65. The concentrations of PVDF (534K) and LiTFSI were 90% by weight of the total concentration, and the concentration of PEST was 10% by weight.

[0211] Then, a slurry and a composite cathode are prepared according to the method for preparing a slurry mixture of a polymer electrolyte composite cathode of the present disclosure. Lithium iron phosphate (LFP) is used as the cathode active material for the composite cathode. The polymer electrolyte mixture is also prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. The polymer electrolyte mixture is then dissolved in acetonitrile (AN) and its solution is cast on the first formed LFP-based composite cathode. AN is evaporated by placing the film in a small pre-combustion chamber in a glove box and causing a slight vacuum. Repeat the process twice to ensure that a dense and uniform film is deposited on the LFP-based composite cathode. Thereafter, a thick Li metal (500 μm) is placed on top and assembled into a coin cell together with the LFP composite cathode having a formed polymer electrolyte layer. The diameter of the LFP composite cathode, polymer electrolyte layer and lithium metal stack is 16 mm.

[0212] Preliminary Example 5-4 (LFP and SiPE variant #1 in pouch cells)

[0213] In Example 5-4, a polymer electrolyte mixture was prepared using the method for preparing a SiPE polymer electrolyte mixture of the present disclosure. PEST was used as the polymer, and LiTFSI and LiBF4 were used as dilithium salts. The concentration of PEST was 80 wt %, the concentration of LiTFSI was 18 wt %, and the concentration of LiBF4 was 2 wt %.

[0214] The steps for preparing the slurry mixture and the composite cathode of the present disclosure are carried out. The cathode active material for the composite cathode is lithium iron phosphate (LFP). Like Example 5-1, the polymer electrolyte mixture is also prepared using the method for preparing a polymer electrolyte mixture of the present disclosure. However, unlike Examples 5-1 and 5-2, the composite cathode, the polymer electrolyte separator layer and the lithium metal anode layer are formed into specifications suitable for pouch cells. The polymer electrolyte mixture is poured into a Teflon evaporating dish, and the solvent is evaporated to form a polymer electrolyte layer. The Teflon evaporating dish has a size suitable for forming a quadrilateral, and a 50mm×50mm square polymer electrolyte layer is formed in this embodiment. Composite cathodes and lithium metal anodes each of 50mm×50mm are similarly formed.

[0215] The composite cathode, polymer electrolyte layer and lithium metal anode are assembled into a pouch cell using the method for assembling a pouch cell of the present disclosure. A lead connector (which may be made of nickel) is welded to the composite cathode and polymer electrolyte layer sheets. The lithium metal anode sheet is cut to be the same size as the composite cathode, and the polymer electrolyte layer is layered together to form a unit cell. The unit cell is inserted between two plastic inserts to provide mechanical rigidity. In addition, an insulating material that may be made of polyolefin is wrapped around the entire unit cell and plastic insert assembly. The assembly is then inserted into a heat-sealed foil and sealed to form a lithium-ion battery pouch cell.

[0216] Pre-Example 6 (NMC811 and SiPE variant #1)

[0217] In Example 6, a SiPE polymer electrolyte mixture was also prepared using the method for preparing a SiPE polymer electrolyte mixture of the present disclosure. PEST was used as the polymer, and LiTFSI and LiBF4 were used as dilithium salts. The concentration of PEST was 80 wt %, the concentration of LiTFSI was 18 wt %, and the concentration of LiBF4 was 2 wt %.

[0218] Then, a slurry and a composite cathode were prepared according to the method for preparing a slurry mixture of a polymer electrolyte composite cathode of the present disclosure. The cathode active material for the composite cathode is lithium nickel manganese cobalt oxide (NMC) (wherein the nickel, manganese and cobalt contents are 80%, 10% and 10%, respectively), and is commonly referred to as NMC811. A SiPE polymer electrolyte mixture was also prepared using the method for preparing a SiPE polymer electrolyte mixture of the present disclosure. The SiPE polymer electrolyte mixture was dissolved in acetonitrile (AN), and its solution was cast on the first formed NMC811-based composite cathode. AN was evaporated by placing the film in a small pre-combustion chamber in a glove box and causing a slight vacuum. The process was repeated twice to ensure that a dense and uniform film was deposited on the NMC811 composite cathode. Thereafter, a thick Li metal (500 μm) was placed on top and assembled into a coin cell together with the NMC811 composite cathode having a formed polymer electrolyte layer. The diameter of the NMC811 composite cathode, polymer electrolyte layer and lithium metal stack was 16 mm.

[0219] The polymer electrolyte of the present disclosure includes a polysiloxane Si-tripod ligand polymer, a lithium salt (e.g., lithium bis(trifluoromethanesulfonyl)imide and / or lithium tetrafluoroborate) and polyvinylidene fluoride. The polymer electrolyte of the present disclosure can be formed into a self-supporting film. The polymer electrolyte of the present disclosure is also formulated into two variants. In variant #1 (Salt in polymer electrolyte (SiPE)), different amounts of polysiloxane Si-tripod ligand polymer, lithium bis(trifluoromethanesulfonyl)imide and lithium tetrafluoroborate are used in multiple embodiments of the present disclosure to formulate the polymer electrolyte to provide the desired ionic conductivity while forming a self-supporting film. In variant #2 (Polymer in salt electrolyte (PiSE)), different amounts of polysiloxane Si-tripod ligand polymer, polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide are used in multiple embodiments of the present disclosure to formulate the polymer electrolyte to provide the desired ionic conductivity while forming a self-supporting film. The polyvinylidene fluoride may be PVDF (534K), PVDF (700K) or PVDF (HSV900).

[0220] The polymer electrolytes are technically and commercially feasible as cathode electrolytes in composite cathodes and as polymer electrolyte separators and can be used together or separately as components of solid-state or semisolid rechargeable batteries. The tested polymer electrolytes exhibited a 1.0×10 -5 S / cm or higher ion conductivity.

[0221] In addition, since polymer electrolytes can be easily manufactured into self-supporting films, their technical and commercial feasibility as cathode electrolytes in composite cathodes or as separators between cathodes and anodes is further improved. Composite cathodes using polymer electrolytes as cathode electrolytes can be relatively easily manufactured by directly solution casting the composite cathode onto a current collector or other substrate. As polymer electrolyte separators, polymer electrolyte solutions can also be cast onto composite cathodes or other substrates. Alternatively, polymer electrolyte separators can be formed without direct solution casting onto composite cathodes. It can be cast onto completely different substrates, peeled off, and then dry placed onto composite cathodes. Compared with the conventional manufacturing process of solid electrolytes in solid-state batteries (which requires significant pressure levels to form electrolytes), these manufacturing processes that do not require high pressure are beneficial. Conventional methods also require polymer electrolytes to be integrated into solid electrolyte materials.

[0222] The composite cathode and polymer electrolyte separator can be used together or separately as components of rechargeable lithium-ion coin cells or pouch cells. The composite cathode and separator can also work with different cathode active materials (such as LFP and NMC811). The composite cathode and polymer electrolyte separator can also be applied to rechargeable lithium-ion batteries with lithium metal anodes.

Claims

1. A polymer electrolyte comprising: Polysiloxane Si-tripod ligand polymer; Lithium bis(trifluoromethanesulfonyl)imide; and Lithium tetrafluoroborate, The polysiloxane Si-tripod ligand polymer, the lithium bis(trifluoromethanesulfonyl)imide and the lithium tetrafluoroborate are formed into a self-supporting film. 2 . The polymer electrolyte according to claim 1 , wherein the polymer electrolyte comprises 70 wt % to 90 wt % of the polysiloxane si-tripod ligand polymer. 3 . The polymer electrolyte according to claim 1 , wherein the polymer electrolyte comprises 8.0 wt % to 29.75 wt % of the lithium bis(trifluoromethanesulfonyl)imide. 4 . The polymer electrolyte according to claim 1 , wherein the polymer electrolyte comprises 0.25 wt % to 3.0 wt % of the lithium tetrafluoroborate.

5. The polymer electrolyte according to claim 1, wherein the ionic conductivity of the polymer electrolyte at a temperature greater than or equal to 25° C. is greater than 1×10 -5 S / cm.

6. A polymer electrolyte comprising: Polysiloxane Si-tripod ligand polymer; Polyvinylidene fluoride; Lithium bis(trifluoromethanesulfonyl)imide; and The polysiloxane Si-tripod ligand polymer, the polyvinylidene fluoride lithium, and the bis(trifluoromethanesulfonyl)imide lithium are formed into a self-supporting film. The polymer electrolyte according to claim 6 , wherein the polyvinylidene fluoride is PVDF (534K). 8 . The polymer electrolyte according to claim 7 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 50:50, the polymer electrolyte comprises 5 wt % to 30 wt % of the polysiloxane Si-tripod ligand polymer. 9 . The polymer electrolyte according to claim 7 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 40:60, the polymer electrolyte comprises 5 wt % to 20 wt % of the polysiloxane Si-tripod ligand polymer. 10 . The polymer electrolyte according to claim 7 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 35:65, the polymer electrolyte comprises 5 to 10 wt % of the polysiloxane Si-tripod ligand polymer. The polymer electrolyte according to claim 6 , wherein the polyvinylidene fluoride is PVDF (700K). 12 . The polymer electrolyte according to claim 11 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 50:50, the polymer electrolyte comprises 5 wt % to 30 wt % of the polysiloxane Si-tripod ligand polymer. 13 . The polymer electrolyte according to claim 11 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 40:60, the polymer electrolyte comprises 5 to 30 wt % of the polysiloxane Si-tripod ligand polymer. 14 . The polymer electrolyte according to claim 11 , wherein when the ratio of the polyvinylidene fluoride to the lithium bis(trifluoromethanesulfonyl)imide is 35:65, the polymer electrolyte comprises 5 to 20 wt % of the polysiloxane Si-tripod ligand polymer.

15. The polymer electrolyte according to claim 6, wherein the polyvinylidene fluoride is PVDF (HSV900). 16 . The polymer electrolyte according to claim 15 , wherein when the ratio of polyvinylidene fluoride to lithium bis(trifluoromethanesulfonyl)imide is 50:50, the polymer electrolyte comprises 5 to 30 wt % of the polysiloxane Si-tripod ligand polymer. 17 . The polymer electrolyte according to claim 15 , wherein when the ratio of polyvinylidene fluoride to lithium bis(trifluoromethanesulfonyl)imide is 40:60, the polymer electrolyte comprises 5 to 25 wt % of the polysiloxane Si-tripod ligand polymer. 18 . The polymer electrolyte according to claim 15 , wherein when the ratio of polyvinylidene fluoride to lithium bis(trifluoromethanesulfonyl)imide is 35:65, the polymer electrolyte comprises 5 to 20 wt % of the polysiloxane Si-tripod ligand polymer.

19. The polymer electrolyte according to claim 6, wherein the ionic conductivity of the polymer electrolyte at a temperature greater than or equal to 25°C is greater than 1×10 -5 S / cm.

20. A method for manufacturing the polymer electrolyte according to claim 1, comprising: dissolving a polysiloxane Si-tripod ligand polymer in a first organic solvent; dissolving lithium bis(trifluoromethanesulfonyl)imide in a second organic solvent; dissolving lithium tetrafluoroborate in the second organic solvent; adding the second organic solvent comprising the lithium bis(trifluoromethanesulfonyl)imide and the lithium tetrafluoroborate to the first organic solvent comprising the polysiloxane Si-tripod ligand polymer to form a mixture; and The mixture is heated under hot conditions to obtain a homogeneous mixture.

21. A method for producing the polymer electrolyte according to claim 6, comprising: dissolving a polysiloxane Si-tripod ligand polymer in a first organic solvent; dissolving lithium bis(trifluoromethanesulfonyl)imide in a second organic solvent; adding polyvinylidene fluoride to the second organic solvent containing the lithium bis(trifluoromethanesulfonyl)imide; adding the second organic solvent comprising the polyvinylidene fluoride and the lithium bis(trifluoromethanesulfonyl)imide to the first organic solvent comprising the polysiloxane Si-tripod ligand polymer; and The mixture is heated under hot conditions to obtain a homogeneous mixture.

22. A composite cathode for a rechargeable battery cell, comprising: cathode active material; Carbonaceous materials; The polymer electrolyte according to claim 1; and a polyvinylidene fluoride binder, wherein the polyvinylidene fluoride binder binds the cathode active material, the carbonaceous material and the polymer electrolyte, wherein the cathode active material, the carbonaceous material, the polyvinylidene fluoride binder and the polymer electrolyte form a cathode film; and The cathode film is formed on a current collector.

23. The composite cathode of claim 22, wherein the polymer electrolyte functions as a cathode electrolyte.

24. The composite cathode of claim 22, wherein the cathode active material is lithium iron phosphate.

25. The composite cathode of claim 22 wherein the cathode active material is lithium nickel manganese cobalt oxide (NMC) and greater than 50% of the NMC is nickel.

26. A composite cathode for a rechargeable battery cell, comprising: cathode active material; Carbonaceous materials; The polymer electrolyte according to claim 6; and a polyvinylidene fluoride binder, wherein the polyvinylidene fluoride binder binds the cathode active material, the carbonaceous material and the polymer electrolyte, wherein the cathode active material, the carbonaceous material, the polyvinylidene fluoride binder and the polymer electrolyte form a cathode film; and The cathode film is formed on a current collector.

27. The composite cathode of claim 26, wherein the cathode active material is lithium iron phosphate.

28. The composite cathode of claim 26 wherein the cathode active material is lithium nickel manganese cobalt oxide (NMC) and greater than 50% of the NMC is nickel.

29. A polymer electrolyte separator for a rechargeable battery cell, the polymer electrolyte separator comprising the polymer electrolyte of claim 1, wherein the polymer electrolyte is formed as a solid layer that is adjacent to a cathode layer and an anode layer of the rechargeable battery cell.

30. The polymer electrolyte separator of claim 29, wherein the solid layer is formed by dry placing the solid layer between the cathode layer and the anode layer.

31. A polymer electrolyte separator for a rechargeable battery cell, the polymer electrolyte separator comprising the polymer electrolyte of claim 6, wherein the polymer electrolyte is formed as a solid layer that is adjacent to a cathode layer and an anode layer of the rechargeable battery cell.

32. The polymer electrolyte separator of claim 31, wherein the solid layer is formed by dry placing the solid layer between the cathode layer and the anode layer.

33. A method for making a composite cathode for a rechargeable battery cell, comprising: The polymer electrolyte is prepared according to the method of claim 20; mixing the polymer electrolyte with a cathode active material, a carbonaceous material, and a polyvinylidene fluoride binder to form a slurry mixture; pouring the slurry mixture onto a current collector; spreading the slurry mixture on the current collector; removing the solvent in the slurry mixture to form a cathode film layer; as well as The cathode film layer and the current collector are calendered.

34. The method of claim 33, wherein the cathode film layer and the current collector are calendered to increase the density of the cathode film layer to 1.7 g / cm 3 .

35. A method for making a composite cathode for a rechargeable battery cell, include: The polymer electrolyte is prepared according to the method of claim 21; mixing the polymer electrolyte with a cathode active material, a carbonaceous material, and a polyvinylidene fluoride binder to form a slurry mixture; pouring the slurry mixture onto a current collector; spreading the slurry mixture on the current collector; removing the solvent in the slurry mixture to form a cathode film layer; as well as The cathode film layer and the current collector are calendered.

36. The method of claim 35, wherein the cathode film layer and the current collector are calendered to increase the density of the cathode film layer to 1.7 g / cm 3 .

37. A method for manufacturing an electrode stack, comprising: Prepare the first and second parts of the polymer electrolyte according to the method of claim 20; The composite cathode is formed by: mixing the first portion of the polymer electrolyte with a cathode active material, a carbonaceous material, and a polyvinylidene fluoride binder to form a slurry mixture; pouring the slurry mixture onto a current collector; spreading the slurry mixture on the current collector; removing the solvent in the slurry mixture to form a cathode film layer; as well as Calendering the cathode film layer and the current collector; forming the second portion of the polymer electrolyte as a separator layer on the composite cathode; forming an anode layer on the negative current collector; as well as stacking the anode layer and the negative current collector on the separator layer, and The separator layer is dry placed on the composite cathode.

38. A method of manufacturing an electrode stack, include: Prepare the first and second parts of the polymer electrolyte according to the method of claim 21; The composite cathode is formed by: mixing the first portion of the polymer electrolyte with a cathode active material, a carbonaceous material, and a polyvinylidene fluoride binder to form a slurry mixture; pouring the slurry mixture onto a current collector; spreading the slurry mixture on the current collector; removing the solvent in the slurry mixture to form a cathode film layer; as well as Calendering the cathode film layer and the current collector; forming the second portion of the polymer electrolyte as a separator layer on the composite cathode; forming an anode layer on the negative current collector; as well as stacking the anode layer and the negative current collector on the separator layer, and The separator layer is dry placed on the composite cathode.

39. A rechargeable battery cell comprising: The composite cathode according to claim 22, wherein the composite cathode is formed as a cathode layer on a first current collector to form a positive electrode; an anode layer, the anode layer being formed on the second current collector to form a negative electrode, wherein the anode layer is lithium metal; as well as A polymer electrolyte separator, the polymer electrolyte separator comprising: A polymer electrolyte, comprising: Polysiloxane Si-tripod ligand polymer; Lithium bis(trifluoromethanesulfonyl)imide; and Lithium tetrafluoroborate, The polysiloxane Si-tripod ligand polymer, the lithium bis(trifluoromethanesulfonyl)imide and the lithium tetrafluoroborate are formed into a self-supporting film, wherein the polymer electrolyte separator is adjacent to the cathode layer and the anode layer, The cathode layer, the anode layer and the polymer electrolyte separator are solid.

40. The rechargeable battery cell of claim 39, wherein the rechargeable battery cell does not contain any liquid electrolyte.

41. The rechargeable battery cell of claim 39, wherein the cathode active material in the composite cathode is lithium iron phosphate.

42. The rechargeable battery cell of claim 39, wherein the cathode active material in the composite cathode is lithium nickel manganese cobalt oxide having a nickel content greater than 50% of the cathode active material.

43. A rechargeable battery cell comprising: The composite cathode according to claim 26, wherein the composite cathode is formed as a cathode layer on a first current collector to form a positive electrode; an anode layer, the anode layer being formed on the second current collector to form a negative electrode, wherein the anode layer is lithium metal; as well as A polymer electrolyte separator, the polymer electrolyte separator comprising: A polymer electrolyte, comprising: Polysiloxane Si-tripod ligand polymer; Polyvinylidene fluoride; Lithium bis(trifluoromethanesulfonyl)imide; and The polysiloxane Si-tripod ligand polymer, the polyvinylidene fluoride lithium and the bis(trifluoromethanesulfonyl)imide lithium are formed into a self-supporting film, wherein the polymer electrolyte separator is adjacent to the cathode layer and the anode layer, The cathode layer, the anode layer and the polymer electrolyte separator are solid.

44. The rechargeable battery cell of claim 43, wherein the rechargeable battery cell does not contain any liquid electrolyte.

45. The rechargeable battery cell of claim 43, wherein the cathode active material in the composite cathode is lithium iron phosphate.

46. ​​The rechargeable battery cell of claim 43, wherein the cathode active material in the composite cathode is lithium nickel manganese cobalt oxide having a nickel content greater than 50% of the cathode active material.

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