Electrodes using radiation curable polymers and / or dispersion additives and methods of manufacture - Patents.com

Abstract

Electrode films utilizing cathode or anode active materials, such as carbon monofluoride (CFx) or MnO2 as the cathode active material, and / or including surfactants, are described. The electrode films can utilize binders including acrylated polyurethane resins, hydroxy-modified acrylated polyurethane resins, acrylate-methacrylate monomer blends, monoacrylates of monoethoxylated phenols, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefins, polyalkylenes, polyethers, styrene-butadiene, copolymers of polysiloxanes, polysiloxanes, branched polyethers, polyvinyl ethers, copolymers thereof, and combinations thereof. The electrode films can further include additives. The electrode films can be electron beam cured.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] All applications in which a foreign or domestic priority claim is identified in an Application Data Sheet or PCT application filed along with this application, including U.S. Provisional Application No. 63 / 267,521, filed February 3, 2022, are incorporated by reference herein under 37 CFR 1.57 and Rules 4.18 and 20.6.

[0002] The present invention relates to energy storage devices, and in particular to compositions for energy storage device electrodes and methods for making energy storage device electrodes. [Background technology]

[0003] Various types of energy storage devices, including, for example, capacitors, batteries, capacitor-battery hybrids, and / or fuel cells, can be used to power electronic devices. Energy storage devices, such as conventional or solid-state lithium ion capacitors or batteries, having electrodes prepared using the improved electrode formulations and / or manufacturing processes can promote improved electrical performance. Lithium ion capacitors or batteries having electrodes prepared using the improved electrode formulations and / or manufacturing processes can exhibit improved cycle performance, reduced equivalent series resistance (ESR) values, increased power density performance, and / or increased energy density performance. The improved electrode formulations and / or manufacturing processes can also promote lower cost energy storage device manufacturing. Summary of the Invention

[0004] For purposes of summarizing the disclosure and the advantages achieved over the prior art, certain objectives and advantages of the disclosure are described herein. Not all such objectives or advantages may be achieved in any particular embodiment. Thus, for example, one skilled in the art will recognize that the invention may be embodied or implemented to achieve or optimize one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or suggested herein.

[0005] In one aspect, a cathode electrode film is described that includes a cathode active material comprising a material selected from the group consisting of carbon monofluoride, manganese dioxide, and combinations thereof, and a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymers of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof.

[0006] In some embodiments, the polyolefin is selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and combinations thereof.

[0007] In some embodiments, a cathode electrode is described that includes a current collector and a cathode electrode film disposed on the current collector. In some embodiments, the cathode electrode further includes a carbon coating disposed between the current collector and the cathode electrode film.

[0008] In some embodiments, an energy storage device is described that includes a cathode electrode, an anode electrode, and a housing, where the cathode and anode electrodes are disposed within the housing.

[0009] In some embodiments, a method of manufacturing a cathode electrode is described, the method including combining a cathode active material, a binder, and a solvent to form a slurry, and casting the slurry onto a current collector to form the cathode electrode. In some embodiments, the method further includes exposing the cathode electrode to an electron beam.

[0010] In one aspect, an electrode film is described that includes an active material and a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymers of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof.

[0011] In some embodiments, the active material is an anode active material.

[0012] In one aspect, an electrode film is described that includes an active material and a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymers of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof, and a surfactant.

[0013] In some embodiments, the active material is a cathode active material. In some embodiments, the cathode active material is selected from the group consisting of carbon monofluoride, manganese dioxide, lithium iron phosphate (LFP), lithium cobalt oxide (LCO), nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), lithium titanate (LTO), lithium manganese iron phosphate (LMFP), and combinations thereof. In some embodiments, the electrode film comprises about 85-95% by weight of the active material.

[0014] In some embodiments, the surfactant is selected from the group consisting of non-ionic surfactants, polymeric surfactants, and combinations thereof. In some embodiments, the surfactant comprises a molecular weight of up to about 50,000 g / mol. In some embodiments, the surfactant is selected from the group consisting of polyethylene glycol derivatives, polyvinylpyrrolidone, poly(ethyleneimine), poly(acrylic acid), and combinations thereof. In some embodiments, the electrode membrane comprises about 0.01-0.5 wt % of the surfactant.

[0015] In some embodiments, the electrode film further comprises a conductive additive. In some embodiments, the electrode film comprises about 1-10 wt % of the conductive additive. In some embodiments, the electrode film comprises about 3-15 wt % of a binder.

[0016] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will become readily apparent to those of ordinary skill in the art from the following detailed description of the preferred embodiments, with reference to the accompanying drawings, and the invention is not limited to any particular preferred embodiment(s) disclosed. [Brief description of the drawings]

[0017] These and other features, aspects, and advantages of the present disclosure will be described with reference to the drawings of specific embodiments that are intended to describe particular embodiments and are not intended to limit the invention.

[0018] [Figure 1] 1 illustrates an assembly structure of a coin cell according to some embodiments.

[0019] [Diagram 2] 1 shows FTIR spectra of resin samples exposed to various amounts of electron beam, according to some embodiments.

[0020] [Diagram 3] 13 shows the results of LSV measurements of prepared cells according to some embodiments.

[0021] [Figure 4A] 1 shows galvanostatic discharge data for cells according to some embodiments as a plot of voltage as a function of specific capacity.

[0022] [Figure 4B] 1 shows galvanostatic discharge data for cells according to some embodiments as a plot of voltage as a function of specific capacity.

[0023] [Figure 4C] 1 shows galvanostatic discharge data for cells according to some embodiments as a plot of voltage as a function of specific capacity.

[0024] [Figure 4D] 1 shows galvanostatic discharge data for cells according to some embodiments as a plot of voltage as a function of specific capacity.

[0025] [Diagram 5] 1 shows the specific capacity of cells as a function of discharge current, according to some embodiments.

[0026] [Figure 6A] 1 illustrates performance metrics for a cell at different weight loadings, according to some embodiments.

[0027] [Figure 6B] 1 illustrates performance metrics for a cell at different weight loadings, according to some embodiments.

[0028] [Figure 7A] 13 illustrates a comparison of pulse performance according to some embodiments.

[0029] [Figure 7B] 13 illustrates a comparison of pulse performance according to some embodiments.

[0030] [Figure 8] 13 illustrates a comparison of pulse performance according to some embodiments.

[0031] [Figure 9] 1 illustrates the specific capacity of an energy storage device, according to some embodiments.

[0032] [Figure 10A-B] FIG. 10A shows galvanostatic discharge data for a MnO 2 cell with an EB-cured binder according to some embodiments as a plot of voltage as a function of specific capacity.

[0033] FIG. 10B shows galvanostatic discharge data for a MnO2 cell with a PVDF cured binder as a plot of voltage as a function of specific capacity according to some embodiments.

[0034] Although specific embodiments and examples are described below, those skilled in the art will recognize that the invention extends beyond the specifically disclosed embodiments and / or uses, and obvious modifications and equivalents thereof. Accordingly, it is intended that the scope of the invention disclosed herein should not be limited by any specific embodiments described below.

[0035] Cathode electrode films utilizing carbon monofluoride (CFx) and other active materials, as well as electrode films utilizing surfactants, are described. The electrodes can utilize binders including, for example, acrylated polyurethane resins, acrylate-methacrylate monomer blends, monoacrylates of monoethoxylated phenols, polyvinylidene fluoride (PVDF), and combinations thereof. The electrodes can be e-beam cured. Such electrode architectures, such as homogeneous, heterogeneous, single-layer, and / or multi-layer electrodes (e.g., heterogeneous multi-layer thin film electrodes), can be flexible and / or bendable and utilized in energy storage devices used in the Internet of Things (IOT) and wearable space. For example, some devices require sufficient Bluetooth Pulse performance, such as the requirements of the Nordic nRF52832 BLE module, and it is important that the power supply voltage never falls below about 1.8V or about 2.0V during sleep and transmission modes, otherwise the BLE connection between the sensor and the reader will be disconnected.

[0036] The energy storage device including the cathode electrode described herein can be a primary or rechargeable energy storage device in various forms. For example, FIG. 1 shows the assembly structure of a lithium-CFx coin cell. The cell in FIG. 1 shows a CFx cathode placed opposite a lithium anode and separated by a separator (e.g., shown as a polypropylene separator), with a bottom gasket placed below the CFx cathode, and a spacer, a cone spring, and a top gasket placed sequentially above the lithium anode. The cell may be filled with an electrolyte before assembly and sealing. In some embodiments, the energy storage device is a battery, a capacitor, or a combination thereof. In some embodiments, the energy storage device is a solid energy storage device, such that the energy storage device includes a solid electrolyte placed between the cathode and the anode. In some embodiments, the solid electrolyte is in a semi-solid (e.g., gel) or solid form.

[0037] The energy storage device may include a first electrode including a first current collector in contact with a first electrode film (e.g., a cathode electrode having a cathode electrode film) and a second electrode including a second current collector in contact with a second electrode film (e.g., an anode electrode having an anode electrode film). The first current collector and the second current collector can facilitate electrical coupling between the corresponding electrode film and an external circuit (not shown). For example, the current collector can include materials including metallic materials such as aluminum, nickel, copper, rhenium, niobium, tantalum, and precious metals such as silver, gold, platinum, palladium, rhodium, osmium, iridium, and alloys and combinations thereof. For example, the current collector can include, for example, aluminum foil or copper foil. The electrode includes at least one electrode film disposed on or over a surface of the current collector. In some embodiments, the electrode may be a multi-layer electrode and may include two or more electrode films, such as a first electrode film and a second electrode film, disposed on the same or different sides of a current collector. In some embodiments, the multi-layer electrode is non-uniform such that the properties, loading, thickness, and / or composition of the first electrode film differs from the properties, loading, thickness, and / or composition of the second electrode film of the electrode.

[0038] The electrode film may comprise a cathode active material or an anode active material. In some embodiments, the electrode film comprises about, at least, or at least about 60%, 65%, 70%, 75%, 80%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% by weight of active material, or any range of values ​​therebetween.

[0039] The cathode active material can include, for example, carbon monofluoride (CFx), a metal oxide, a metal sulfide, or a lithium metal oxide. The lithium metal oxide can be, for example, lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), lithium titanate (LTO), and / or lithium nickel cobalt aluminum oxide (NCA). In some embodiments, the cathode active material can be, for example, a layered transition metal oxide (e.g., LiCoO2 (LCO), Li(NiMnCo)O2 (NMC), and / or LiNi 0.8 Co 0.15 Al 0.05 O2(NCA)), spinel-type manganese oxides (e.g., LiMn2O4(LMO), and / or LiMn 1.5 Ni 0.5 O4 (LMNO)), olivine (e.g., LiFePO4), chalcogenides (LiTiS2), tavorite (LiFeSO4F), silicon, silicon oxide (SiOx), aluminum, tin, tin oxide (SnOx), manganese oxide (MnOx) (e.g., manganese dioxide "MnO2"), molybdenum oxide (MoO2), molybdenum disulfide (MoS2), nickel oxide (NiOx), or copper oxide (CuOx).

[0040] The anode active material can include, for example, an intercalation material (e.g., carbon, graphite (natural, synthetic, or blend), hard or amorphous carbon, and / or graphene), an alloy / dealloy material (e.g., silicon, silicon oxide, tin, and / or tin oxide), a metal element, a metal alloy or compound (e.g., Si-Al, and / or Si-Sn), and / or a conversion material (e.g., manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The anode active materials can be used alone or mixed together to form a multiphase material (e.g., Si-C, Sn-C, SiOx-C, SnOx-C, Si-Sn, Si-SiOx, Sn-SnOx, Si-SiOx-C, Sn-SnOx-C, Si-Sn-C, SiOx-SnOx-C, Si-SiOx-Sn, Sn-SiOx-SnOx).

[0041] The electrode film can include a binder. In some embodiments, the electrode film includes about, at least, or at least about 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or 25% by weight of binder(s), or any value range therebetween. In some embodiments, the binder is a polymerizable binder. In some embodiments, the polymerizable binder is electron beam ("e-beam" or "EB") polymerizable. The binder can include acrylated polyurethane resins (e.g., Ucecoat 7689, Ucecoat 7510, and Ucecoat 7690 (i.e., polyurethane acrylate, acrylate ester, and / or acrylate monomer dispersion in water)), hydroxy-modified acrylated polyurethane resins (e.g., hydroxy-modified Ucecoat 7690), acrylate-methacrylate monomer blends (e.g., Ebecryl 109), monoacrylates of monoethoxylated phenols (e.g., Ebecryl 114), trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefins, polyalkylenes, polyethers, styrene-butadiene, copolymers of polysiloxanes, polysiloxanes, branched polyethers, polyvinyl ethers, copolymers thereof, and combinations thereof. The binder can include cellulose, e.g., carboxymethyl cellulose (CMC). In some embodiments, the polyolefin may include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and / or combinations thereof.For example, the binder can include polyvinylene chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-co-alkylmethylsiloxane, copolymers thereof, and / or mixtures thereof. In some embodiments, the binder can include acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, polyvinylidene fluoride (PVDF), and combinations thereof. In some embodiments, the binder can include acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, and combinations thereof.

[0042] In some embodiments, the electrode film can include one or more metal, metal oxide, and / or carbon material additives. In some embodiments, the carbon material additive can be a conductive additive (e.g., Super-P C65) and / or a high aspect ratio additive. The carbon material can be selected from, for example, graphitic materials, graphite, graphene-containing materials, hard carbon, soft carbon, carbon nanotubes, carbon nanofibers, porous carbon, conductive carbon, or combinations thereof. In some embodiments, the graphitic material can be a surface-treated material. In some embodiments, the porous carbon can include activated carbon. In some embodiments, the porous carbon can include hierarchically structured carbon. In some embodiments, the porous carbon can include structured carbon nanotubes, structured carbon nanowires, and / or structured carbon nanosheets. In some embodiments, the porous carbon can include graphene sheets. In some embodiments, the porous carbon can include surface-treated carbon. In some embodiments, the metal or metal oxide additive includes an element selected from tin, titanium, iron, zirconium, or combinations thereof. In some embodiments, the metal oxide additive comprises an acidified metal oxide (e.g., TENIX®). In some embodiments, the electrode film comprises about, at most, or at most about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by weight of the additive, or any value range therebetween.

[0043] In some embodiments, the electrode film may include a surfactant. In some embodiments, the surfactant is selected from a hydrocarbon surfactant, a fluorosurfactant, a silicon surfactant, a polyoxypropylene surfactant, and combinations thereof. In some embodiments, the surfactant is selected from an amphiphilic surfactant, a cationic surfactant, an anionic surfactant, a nonionic surfactant, a polymeric surfactant, a biosurfactant, and combinations thereof. In some embodiments, the surfactant includes a polyethylene glycol derivative (e.g., Triton X-100* (Sigma, molecular weight 695 g / mol)), polyvinylpyrrolidone (PVP), cationic poly(ethyleneimine) (PEI, Sigma Aldrich, molecular weight 10,000 g / mol), and anionic poly(acrylic acid) (PAA, Sigma Aldrich, molecular weight 15,000 g / mol). In some embodiments, the surfactant provides properties such as emulsification, dispersion, and solubilization for lowering surface tension and energy, casting and / or drying of the electrode film. In some embodiments, the surfactant includes a structure directing agent, a carbon source, a porogen agent, and a stabilizer. In some embodiments, the surfactant comprises a molecular weight of about, at most, or at most about 300 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 1,000 g / mol, 2,000 g / mol, 5,000 g / mol, 10,000 g / mol, 15,000 g / mol, 20,000 g / mol, 30,000 g / mol, 40,000 g / mol, 50,000 g / mol, 60,000 g / mol, or 80,000 g / mol, or any range of values ​​therebetween.In some embodiments, the electrode film comprises about, at most, or at most about 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by weight of a surfactant, or any value range therebetween. ※Triton X-100 [ka]

[0044] The energy storage device can include any number of different types of electrolytes. For example, in some embodiments, the device can include a lithium ion battery electrolyte, which can include a lithium source, such as a lithium salt, and a solvent, such as an organic solvent. In some embodiments, the device can further include an additive, such as a solid electrolyte interface (SEI) forming additive, an electrode wetting additive, or a separator wetting additive. In some embodiments, the lithium salt can be lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiB F4 ), lithium perchlorate (LiClO4), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2), lithium trifluoromethanesulfonate (LiSO3CF3), lithium bis(pentafluoroethanesulfonyl)imide (C4F 10LiNOS2), lithium bis(fluorosulfonyl)imide (F2LiNO4S2), lithium bis(oxalato)borate (LiB(C2O4)2), lithium difluoro(oxalato)borate (LiBF2(C2O4), lithium difluorophosphate (F2LiO2P), lithium oxalyl difluoroborate, lithium trifluorochloroborate (LiBF3Cl), lithium hexafluoroarsenate (LiAsF6), combinations thereof, and / or the like. In some embodiments, the lithium ion electrolyte solvent may include one or more ethers, and / or esters. For example, the lithium ion electrolyte solvent can include ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), vinyl carbonate (VC), propylene carbonate (PC), combinations thereof, and / or the like. For example, the electrolyte can include LiPF6, ethylene carbonate, propylene carbonate, and diethyl carbonate. In some embodiments, the device can include a solid electrolyte. In some embodiments, the solid electrolyte also functions as a separator.

[0045] The electrodes described herein can be prepared by a variety of processes. As an example, in some embodiments, an electrode film mixture (e.g., including active materials, binders, and optionally additives) is combined with a solvent to form an electrode film slurry. In some embodiments, the solvent is an aqueous solvent, an organic solvent, or a combination thereof. As another example, in some embodiments, an electrode film mixture (e.g., including active materials, binders, and optionally additives) is combined to form an electrode film in a solvent-free dry electrode manufacturing process. In some embodiments, the electrode film mixture further includes a surfactant and / or an additive (e.g., a conductive additive). In some embodiments, the solvent includes water, N-methylpyrrolidone (NMP), other organic solvents, or a combination thereof. The electrode film slurry can then be cast onto a substrate to form a cast electrode film. In some embodiments, the casting of the electrode film slurry can be performed using a doctor blade, spray coating, comma bar, slot die, aerosol, gravure, screen printing, imprinting, spin coating, electrospinning, and combinations thereof. The as-cast electrode film can then be dried and / or cured to form the electrode film. In some embodiments, the as-cast electrode film, or electrode film, is calendered (e.g., a roll-to-roll process). In a solvent-free dry electrode manufacturing process, the electrode film can be formed using dry materials, such as in a calendering process. In some embodiments, the dry electrode film, or the substrate onto which the electrode film slurry is cast, is the current collector, and thus an electrode is formed once the electrode film is deposited, dried, and / or cured.

[0046] Drying can be performed by heating the as-cast electrode film to evaporate the solvent. Curing can be performed to polymerize the binder to form a binder matrix within the electrode film. In some embodiments, curing is performed by an energy source, such as, for example, photons and / or electrons. In some embodiments, curing is performed by an electron beam ("e-beam", or "EB"). In some embodiments, curing is performed with an EB having about, at least, or at least about 50 kV, 100 kV, 150 kV, 200 kV, 250 kV, 300 kV, or any range of values ​​therebetween. In some embodiments, curing is performed with an EB having about, at least, or at least about 15 kGy, 20 kGy, 25 kGy, 30 kGy, 40 kGy, 50 kGy, 60 kGy, 70 kGy, 80 kGy, or 100 kGy, or any range of values ​​therebetween. EXAMPLES

[0047] Exemplary embodiments of the present disclosure, including processes, materials, and / or resulting products, are described in the following examples.

[0048] Example 1 - EB formulation Battery electrode slurries were made using active materials (e.g., carbon monofluoride (CFx), or MnO2), conductive additives (e.g., Super-P C65), radiation curable binders (e.g., Ucecoat 7690 ("UC7690", or "UC90")) as the primary polymer binder, cellulosic polymers (e.g., aqueous carboxymethylcellulose (CMC), and Na-CMC, or cellulosic polymers such as methylcellulose) as the secondary binder, and in some cases surfactants were used for wetting. Different surfactants used included non-ionic Triton X-100 with a molecular weight of 695 g / mol, cationic poly(ethyleneimine) (PEI) with a molecular weight of 10,000 g / mol, and anionic poly(acrylic acid) (PAA) with a molecular weight of 15,000 g / mol. The slurries were made by sequentially adding each of the ingredients to water and dispersing them using various dispersing techniques, including a Flacktek SpeedMixer, a Thinky Mixer, and / or a planetary mixer. Table 1 summarizes the weight percent solids of each of the formulations. [Table 1]

[0049] Once well dispersed, the slurry was then used to fabricate battery electrodes by casting onto an aluminum substrate using a doctor blade. After deposition, the resulting electrode film was air-dried for 15-20 minutes to remove water from the electrode film, followed by placing it under a forced air dryer held at 120°C for 10-15 minutes. The electrodes were then calendered at 80°C until a porosity of 40% was achieved for each. Once the electrodes were dry, select ones were cured using electron beam (EB) at various high voltages (140kV-200kV) and doses (20kGy-100kGy) under an inert nitrogen atmosphere, while the rest were left uncured. Each cured electrode was cured such that a dose of 20kGy was achieved throughout the entire depth of the film. Table 2A shows examples of typical electrode loadings for EB formulations F1, F2, and F3. [Table 2A]

[0050] The use of UC7690 as the radiation polymer binder in the slurry mix produced good rheological qualities. Additionally, the surfactants added to each formulation improved the dispersion of the hydrophobic CFx, without which successful dispersion did not occur.

[0051] Example 2 - PVDF formulation Battery electrode slurries were made using carbon monofluoride (CFx) as the active material, Super-P C65 (conductive carbon black powder) as the conductive additive, and polyvinylidene fluoride (PVDF) in N-methylpyrrolidone (NMP) as the polymer binder. The slurries did not contain surfactants. The slurries were made by sequentially adding each of the components to an NMP solution and dispersing them using various dispersing techniques, including a Flacktek SpeedMixer, a Thinky Mixer, and / or a planetary mixer. Once sufficiently dispersed, the slurries were then used to make battery electrodes by techniques including doctor blades, spray coating, comma bars, and / or slot dies to deposit the slurry material onto a substrate by a roll-to-roll process. Substrates used during deposition included aluminum foil, and carbon-coated aluminum foil, with a concentration of 20-30 mg / cm. 2 Various solids weight loadings between 100 and 2000g were achieved. After deposition, the resulting electrode films were dried using a convection drying process to remove the volatile NMP solvent therefrom. After the solvent was removed from the electrodes, the solvent was recovered through a solvent recovery process. The electrodes were first dried in a convection oven at 80° C. for 10 minutes, calendered to 40% porosity at 80° C., and subsequently vacuum dried at 100° C. for 12 hours. Table 2B shows examples of typical electrode loadings for EB formulations F7 and F8. [Table 2B]

[0052] Example 3 - EB curing When acrylate-based polyurethane resins are exposed to an electron beam, these resins undergo free radical-induced polymerization reactions resulting in crosslinking of adjacent acrylate groups. The relative degree of crosslinking in exposed samples of acrylate polyurethane resins can be discerned by Fourier transform infrared (FTIR) spectroscopy. -1 The intensity of the characteristic absorption peak of the C=C bond in each of the nearby acrylate groups corresponds to the concentration of unreacted arylate groups after exposure. FTIR spectra of cured and uncured samples of Ucecoat 7689 were collected using a VERTEX 70v spectrometer at the Nanoscale Characterization Facility at Indiana University. Each sample was prepared by depositing pure Ucecoat 7689 resin onto a glass substrate and casting it across the surface using a doctor blade. The resin was then dried and then placed in the electron beam emitter chamber for exposure. To reduce the presence of oxygen that may inhibit crosslinking, the chamber was purged with 99.99% pure nitrogen gas before turning on the emitter, and the gas flow was maintained throughout the exposure of each sample. The samples were exposed to a range of high voltages and doses, from 100 to 200 kV and 30 to 60 kGy, respectively. An uncured sample was also prepared as a reference for the FTIR measurements. The FTIR spectra obtained for each of the different samples are shown in Figure 2. Each measurement was taken on a Vertex 70v spectrometer using a 4 cm -1 The final curves were determined by averaging over 32 separate scans collected in transmission mode at a resolution of 100 Å. A clear trend of decreasing peak intensity with increasing EB voltage and dose compared to the uncured sample is clearly observed, indicating crosslinking of more acrylate groups.

[0053] Example 4 - Linear Sweep Voltammetry To investigate any differences in electrochemistry that may exist between cells containing PVDF binder and EB-curable polymer, linear sweep voltammetry (LSV) measurements were performed on each type of coin cell. During cell discharge in the Li-CFx system, lithium ions flow from the anode, through the electrolyte and separator, to the CFx cathode, and electrons simultaneously travel through the external circuit to reduce the cathode. The overall cell discharge reaction can be summarized by the following: CFx+xLi→C+xLiF The half reactions at the anode and cathode are: Anode: xLi+xS→xLi + S+xe - Cathode: CF x +xLi + S+xe - →C+xLiF+xS In the formula, S is the number of Li atoms in the ion flow. +represents the electrolyte solvent molecules coordinated with. LSV allows the voltage window of interest to be swept at a fixed scan rate (potential change per unit time) and the oxidation and reduction reactions to be observed as a change in current within the scan range. Linear sweep voltammetry (LSV) profiles were collected in a voltage window from the open circuit potential (about 3.25 V for each cell) to 1 V at a scan rate of 0.1 mV / s. Figure 3 shows the results of LSV measurements of PVDF cells in EB cured and uncured forms compared to those containing a polymer electrode made using the F2 formulation. Multiple cells of each type were tested and representative curves were extracted for each. A clear reduction peak near 1.85 V is observed for the PVDF system. The cells containing the cured and uncured EB polymer electrodes show a reduction peak occurring at a slightly lower reduction potential, with the uncured sample shifted to about 1.8 V and the cured at about 1.75 V. The area of ​​the reduction peak for the PVDF sample was larger than that of the EB sample, indicating an increased amount of active material participating in the redox reaction. This was a result of a slightly higher weight loading of the PVDF electrode compared to the EB electrode. Figure 3 shows no obvious false peaks, indicating that undesired side reactions are visible during the measurements. Thus, these measurements show that the EB polymer, whether cured or uncured, is electrochemically inactive over the potential window of interest for discharging Li-CFx cells.

[0054] Example 6 - Discharge performance To evaluate the discharge performance of the EB Li-CFx cells, galvanostatic discharge data was collected on a Neware CT-4008T battery analyzer at various weight loadings and currents. 2 , 26.0 mg / cm 2 , and 53.0 mg / cm 2Cells made using formulation F1 with surfactant Triton X-100, with a weight loading of 26.0 mg / cm were discharged at constant currents of 250 μA, 500 μA, and 1 mA, respectively. The cells were discharged from their open circuit potential (approximately 3.25 V) to a cutoff voltage of 2.0 V. Prior to cell assembly, all EB CFx electrodes used to make the cells were cured such that a dose of 20 kGy was achieved throughout the entire depth of the film. The surfactant-free PVDF cells were also discharged at a constant current of 26.0 mg / cm. 2 The PVDF cells were assembled with CFx electrodes at a weight loading of 12.5 mg / cm and discharged at the same constant current values ​​as the EB cells. Figures 4A-4D show the galvanostatic discharge data for the EB and PVDF cells as plots of voltage as a function of specific capacity, with Figure 4A showing a specific capacitance of 12.5 mg / cm. 2 FIG. 4B shows the discharge data for the EB electrode with a load of 26.0 mg / cm 2 FIG. 4C shows the discharge data for the EB electrode with a load of 53.0 mg / cm 2 FIG. 4D shows the discharge data for the EB electrode with a load of 26.0 mg / cm 2 Figure 1 shows discharge data for a loaded PVDF electrode. Each curve is an average discharge curve across multiple tested cells discharged at the same weight load and current value. All cells show a voltage delay at the beginning of discharge.

[0055] The EB cells with surfactants exhibit an initial delayed voltage drop of about 0.5 V compared to a voltage drop of about 0.25 V for the PVDF cells without surfactants, implying that the electronic conductivity of the EB cathode is lower than that of its PVDF counterpart during the initial discharge phase. All cell types exhibit a voltage plateau above 2.5 V when discharged at 250 uA, with a monotonic decrease in the observed plateau at larger discharge currents. This monotonic decrease in voltage with increasing discharge current is due to the presence of solvated Li. + The higher the discharge rate, the greater the potential difference between the Li ions. + A greater bond strength is induced between the cathode and the electrolyte solvent, making it more difficult to form the lithium-fluorine (Li-F) couple within the cathode. 2) compared to the lower weight loading samples, small differences in the shape of the voltage plateaus are observed, but the 12.5 and 26.0 mg / cm 2 The curves for show a similar shape regardless of the binder system used. The PVDF cell without surfactant achieves a specific capacity of 800 mAh / g at 250 μA, while the EB cell with surfactant achieves a higher value of 880 mAh / g when discharged at the same current value. Furthermore, the EB cell with surfactant showed approximately 15% increase in energy density and improved current compared to the PVDF cell without surfactant at the same weight loading.

[0056] FIG. 5 shows the specific capacity of these cells as a function of discharge current, where each point is determined by extracting the specific capacity at the voltage cutoff of the galvanostatic discharge curve, where all tested EB cells had a specific capacity of 26.0 mg / cm, regardless of weight loading. 2 It is clear that the PVDF-based cellulose esters exhibit higher relative specific capacitance values ​​compared to their PVDF counterparts.

[0057] Theoretical specific discharge capacity of CFx (Q th ) can be written as a function of x (the ratio of F to C) as follows:

number

[0058] Figures 6A and 6B are Ragone plots providing an overview of the performance metrics of EB and PVDF cells as a function of their specific capacity at different discharge currents. Figures 6A and 6B show the relationship between energy density (Wh / kg) and power density (W / kg) for different cell types. Energy density (E) and power density (P) are determined from the discharge curves using the following two equations:

number

[0059] FIG. 6A shows the performance metrics of the EB cell at different weight loadings. The points shown represent the average of multiple discharge curves, with values ​​extracted at different cell voltage cutoffs. The error bars for each point indicate the standard deviation away from the mean of all cells considered in both the horizontal and vertical directions. As expected for cells with thicker electrodes, a trend towards decreasing power density is observed for cells with increasing weight loadings. FIG. 6B shows the performance metrics of the EB cell at 26.0 mg / cm 2 Figure 1 shows a comparison of EB and PVDF cells at the same weight loading of 10 ...

[0060] Example 8 - Discharge performance Discharge testing set a cutoff voltage condition of 1.8V and tested all coin cells from each type of EB formulation and PVDF cell. The cells were cycled through a sequence of constant current "rest" discharge steps at 20uA for 5 minute intervals, followed by a 6ms pulse "event" at 7.6mA. This sequence was repeated for a total time frame of 200 hours, at which point each cell was discharged to its final capacity at 300uA.

[0061] FIG. 7A shows a comparison of pulse performance after 12 hours of discharge at 20 uA between a cured EB cell of Formulation F1 with surfactant and a PVDF cell without surfactant, each cast on an aluminum foil substrate. During testing, a voltage delay was observed for all cell types during the initial cell discharge. This voltage delay is directly reflected in the pulse test where the cell immediately begins pulsing, with some cured EB cells with surfactant showing a substantial voltage drop from the OCV to less than 0 V during the initial discharge. The effect of this voltage delay was also reflected in the PVDF electrode without surfactant coated on an aluminum substrate, with a voltage drop from the OCV to less than 1.0 V, as seen in FIG. 7B. It was found that this voltage drop could be reduced if the cell was first discharged for 12 hours prior to the pulse test.

[0062] After the initial discharge, the PVDF without the surfactant cell maintains a voltage above 2 V throughout the remainder of the experiment, with a relatively constant pulse voltage drop of approximately 0.5 V. In comparison, the EB with the surfactant cell exhibits significant voltage delay after the 12 hour treatment period, with a monotonically decreasing pulse voltage drop starting at values ​​above 1.5 V after the pulse begins. This increased voltage delay for the EB with the surfactant cell reflects issues with electronic conductivity, and the rate capabilities of the CFx chemistry.

[0063] By repeatedly testing different curing conditions of EBs with surfactant formulations, voltage delay and rate performance were improved. Surprisingly, it was found that EBs with surfactant cells containing uncured CFx cathodes showed improved pulse performance compared to those cured cells. Each EB with surfactant cell type (i.e., F1, F2, F3, F4, and F5) showed improved pulse performance and voltage delay when the internal CFx cathode was left uncured, with the F2 formulation showing the best performance. Figure 7B shows a comparison between an uncured EB with a surfactant cell made using F2 and PVDF without a surfactant cell, both cast on an aluminum substrate. This cell shows much improved performance over the cured F1 cell shown in Figure 7A, with no apparent voltage delay and the voltage being maintained above 2V throughout the entire test period.

[0064] Furthermore, Figure 7B shows that early in the pulsing sequence (large panel), it becomes apparent that each cell type performs similarly, with a voltage drop of about 0.5 V when tested over the course of 10 hours, and over a larger time frame within the test (figure inset), the voltage drop for uncured EB with surfactant remains relatively constant, while the voltage drop for PVDF without surfactant decreases, dropping below a minimum threshold of about 1.5 V during discharge. This indicates that the pulsing performance of Li-CFx batteries can be enhanced by using an EB binder as the polymer of choice, rather than PVDF, even when that polymer has not undergone an electron beam curing process.

[0065] Example 9 - Carbon-coated Al FIG. 8 shows the results of pulsing performance of coin cells with electrodes containing PVDF binder and cast on either bare aluminum or carbon-coated aluminum substrates. In FIG. 8 (large panel) with tests up to 10 hours, it can be seen that early in the pulsing sequence, each cell type performs similarly, with a voltage drop of about 0.5 V when tested for 10 hours. However, a longer time frame within the 180 hour long-term test (inset) reveals that the voltage drop of the cell made with carbon-coated aluminum foil is improved, with the voltage never dropping below 2.0 V during more than 150 hours of pulsing, while the voltage drop of the aluminum foil is reduced, dropping 1.5 V below the minimum threshold of about 1.8 V. This indicates that the carbon-coated aluminum foil can enhance the electronic conductivity of the substrate during operation of the resulting CFx battery cell.

[0066] Example 10 - NMC electrode A formulation was prepared with NMC532 as the active material, containing NMC / C65 / UC7690 / CMC / Solsperse 39000 (polymeric dispersant, Lubrizol) 87 / 5 / 7 / 0.5 / 0.5 by weight percent solids, with a solids to water ratio of 69:31. The cathode slurry was coated and subsequently subjected to different curing conditions, such as uncured, 140 kV, and 200 kV e-beam curing (30 kGy). These electrodes were then assembled into rechargeable half-cells and cycled at different rates (C / 10 and C / 5). Figure 9 shows the specific capacity of the e-beam cured and thermally cured batteries over 10 cycles. This study showed that the e-beam cured batteries had only 20% lower performance compared to the thermally cured batteries, but this was highly dependent on the e-beam conditions. Thus, the results show that the e-beam manufacturing process can be adopted for rechargeable batteries.

[0067] Example 11 - MnO2 cell discharge performance To evaluate the discharge performance of EB Li-MnO2 batteries, galvanostatic discharge data was collected for batteries fabricated using Formulation F6. Figures 10A and 10B show the galvanostatic discharge data for EB Li-MnO2 cells with EB radiation cured binder or PVDF binder, respectively, as plots of voltage as a function of specific capacity. Figures 10A and 10B show that radiation cured polymers with MnO2 as the active material can produce batteries with similar performance to PVDF-based batteries while retaining the manufacturing advantages of radiation cured batteries.

[0068] Although specific embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. In addition, various omissions, substitutions, and modifications of the systems and methods may be made without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the present disclosure.

[0069] It should be understood that features, materials, properties, or groups described in connection with a particular aspect, embodiment, or example are applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, unless incompatible therewith. All of the features disclosed in this specification (including the accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any of the foregoing embodiments. Protection extends to any novel, or any novel combination of features disclosed in this specification (including the accompanying claims, abstract, and drawings), or any novel, or any novel combination of steps of any method or process so disclosed.

[0070] Moreover, certain features that are described in this disclosure in the context of separate embodiments can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single embodiment can also be implemented separately in multiple implementations or in any suitable subcombination. Furthermore, although features may be described above as acting in a particular combination, one or more features from a claimed combination can, in some cases, be deleted from the combination, and the combination can be claimed as a subcombination or a variation of the subcombination.

[0071] Furthermore, although operations may be shown in the figures or described herein in a particular order, such operations need not be performed in the particular order shown, or in sequential order, or all operations need not be performed to achieve desirable results. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Furthermore, operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the embodiment, certain steps of the steps described above may be omitted and other steps may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. It should also be understood that the separation of various system components in the above implementations should not be understood to require such separation in all implementations, and that the described components and systems may generally be integrated together in a single product or packaged into multiple products. For example, any of the components of the energy storage systems described herein may be provided separately or may be integrated (e.g., packaged or attached together) to form an energy storage system.

[0072] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not all such objects or advantages may be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will recognize that the invention may be embodied or implemented to achieve one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0073] Conditional language such as "can," "could," "might," or "may," unless otherwise specified or understood otherwise within the context in which it is used, is generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not. Thus, such conditional language does not generally imply that the features, elements, and / or steps are in any way required by one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included in or performed in any particular embodiment, with or without user input or prompting.

[0074] Conjunctions such as the phrase "at least one of X, Y, and Z," unless otherwise noted, are understood in the context in which they are generally used to convey that an item, term, etc. can be either X, Y, or Z. Thus, such conjunctions are generally not intended to imply that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0075] As used herein, language of degree, such as "approximately," "about," "generally," and "substantially," refers to a value, amount, or characteristic that is close to a stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" can refer to amounts that are less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the stated amount, depending on the desired function or result.

[0076] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere herein, but may be defined by the claims, as presented in this section or elsewhere herein, or as presented in the future. The language of the claims should be interpreted broadly based on the language used in the claims, and not limited to the examples described herein or during prosecution of the application, which examples should be interpreted as non-exclusive.

[0077] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the apparatus and methods disclosed herein.

Claims

1. a cathode active material comprising a material selected from the group consisting of carbon monofluoride, manganese dioxide, and combinations thereof; a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymer of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof; a cathode electrode film comprising:

2. 2. The cathode electrode membrane of claim 1, wherein the polyolefin is selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and combinations thereof.

3. A cathode electrode comprising: a current collector; and the cathode electrode film of claim 1 disposed on the current collector.

4. 4. The cathode electrode of claim 3, further comprising a carbon coating disposed between the current collector and the cathode electrode film.

5. An energy storage device comprising: the cathode electrode of claim 3; an anode electrode; and a housing, wherein the cathode and anode electrodes are disposed within the housing.

6. 4. The method of manufacturing the cathode electrode of claim 3, comprising: combining the cathode active material, a binder, and a solvent to form a slurry; and casting the slurry onto the current collector to form the cathode electrode.

7. The method of claim 6 further comprising exposing the cathode electrode to an electron beam.

8. An active material; a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymer of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof; an electrode film comprising:

9. 9. The electrode of claim 8, wherein the active material is an anode active material.

10. An active material; a binder selected from the group consisting of acrylated polyurethane resin, hydroxy-modified acrylated polyurethane resin, acrylate-methacrylate monomer blend, monoacrylate of monoethoxylated phenol, cellulose, trimethylolpropane ethoxy triacrylate (TMPEOTA), polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymer of polysiloxane, polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and combinations thereof, and a surfactant; an electrode film comprising:

11. The electrode film of claim 10 , wherein the active material is a cathode active material.

12. 12. The electrode film of claim 11, wherein the cathode active material is selected from the group consisting of carbon monofluoride, manganese dioxide, lithium iron phosphate (LFP), lithium cobalt oxide (LCO), nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), lithium titanate (LTO), lithium manganese iron phosphate (LMFP), and combinations thereof.

13. The electrode film according to any one of claims 10 to 12, wherein the electrode film comprises 85 to 95 wt% of an active material.

14. The electrode film according to any one of claims 10 to 12, wherein the surfactant is selected from the group consisting of nonionic surfactants, polymeric surfactants, and combinations thereof.

15. The electrode film according to any one of claims 10 to 12, wherein the surfactant comprises a molecular weight of at most 50,000 g / mol.

16. 13. The electrode film according to any one of claims 10 to 12, wherein the surfactant is selected from the group consisting of polyethylene glycol derivatives, polyvinylpyrrolidone, poly(ethyleneimine), poly(acrylic acid), and combinations thereof.

17. The electrode film according to any one of claims 10 to 12, wherein the electrode film contains 0.01 to 0.5 wt% of a surfactant.

18. The electrode film according to any one of claims 10 to 12, further comprising a conductive additive.

19. The electrode film according to claim 18, wherein the electrode film comprises 1 to 10 wt % of a conductive additive.

20. The electrode film according to any one of claims 10 to 12, wherein the electrode film comprises 3 to 15 wt% of a binder.

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