Supramolecular Binders

Abstract

The present disclosure provides water-based binders that address the challenges associated with simple linear polymer binders. In some embodiments, the binders contain Lewis acid and Lewis base moieties that chemically interact. Different species, such as two different types of polymers, or a linear polymer and particles (e.g., made of different polymers), can be used. The first species may have only Lewis acid moieties therein (e.g., on it), and the second species may have only Lewis base moieties therein (e.g., on it). In some embodiments, a linear polymer containing Lewis base moieties (e.g., in its backbone) and polymer particles containing Lewis acid moieties are used to form a supramolecular binder in which the Lewis acid and Lewis base moieties chemically interact.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 434,006, filed December 20, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to binders, in some embodiments, for electrochemically active materials for electrodes for use in electrochemical cells. [Background technology]

[0003] Lithium-based batteries generally utilize electrodes that are a combination of electrochemically active material, conductive carbon, and binder. Generally, the binder and conductive carbon content is minimized to achieve the highest possible energy and / or power density for the battery. This typically balances the mechanical properties of the cathode (e.g., adhesion, bending radius, cohesion) with energy density. If the cathode particles in the film have a high surface area, more binder may be required due to the binder's affinity for the particle surface.

[0004] Binders used in lithium-ion batteries are typically linear polymers that are soluble in aqueous or organic solvents. Aqueous solvents are generally preferred due to their low toxicity, low environmental impact, low cost, and lack of the need for expensive solvent recovery systems. Linear polymers are generally less suitable for applications requiring high mechanical strength than cross-linked polymers. This is because linear polymers generally have lower cohesive forces between polymer chains. Furthermore, high-strength linear polymers generally do not dissolve in aqueous solutions.

[0005] Furthermore, cathode mixes used in lithium-sulfur batteries are characterized by high amounts of high-surface-area conductive carbon, which makes it difficult to optimize the binder content. For example, the high surface area of ​​the cathode solids typically requires a relatively high mass fraction of binder to achieve good mechanical properties, which leads to surface blockage, a reduction in overall surface area per unit volume, and a decrease in energy density. Because charge transfer occurs from the surface of the conductive cathode component to the electrochemically active sulfur, a reduction in surface area can result in a decrease in capacity and rate. Summary of the Invention [Means for solving the problem]

[0006] The present disclosure provides a binder system that addresses the challenges associated with simple linear polymer binders. The binder may have high strength while being processable in aqueous media. To achieve these goals, among others, the binders disclosed herein utilize chemical interactions between Lewis acid and Lewis base moieties. Different species, such as two different types of polymers, or a linear polymer and particles (e.g., made of different polymers) may be used. The first species may have only Lewis acid moieties therein (e.g., on it), and the second species may have only Lewis base moieties therein (e.g., on it). In some embodiments, a linear polymer containing Lewis base moieties (e.g., in its backbone) and polymer particles containing Lewis acid moieties are used to form a supramolecular binder resulting from the interaction of the Lewis acid moieties and the Lewis base moieties. Thus, in some embodiments, the binder defines (e.g., forms) a supramolecular polymer network in the composition formed by the interacting Lewis acid and Lewis base moieties. In some embodiments, cationic and anionic polymers are used to form binders with chemically interacting Lewis acid and Lewis base sites. The binders disclosed herein have been incorporated into positive electrode compositions for lithium-sulfur batteries and have shown unexpectedly significant improvements in cycle life, cell impedance growth, and / or energy density.

[0007] Chemical interactions between Lewis acid sites and Lewis base sites (e.g., on different species) can act like non-covalent crosslinks, thereby providing the benefits typically associated with chemical crosslinking without the need to form covalent crosslinks. Thus, the manufacture of electrode compositions can be simplified by using the binders disclosed herein. Covalent crosslinks typically require additional processing steps, such as photoinitiation or high-temperature heat treatment, to form the crosslinks. In some embodiments, the binders disclosed herein may be formed during slurry-based deposition of the electrode composition without the need for any additional crosslinking steps. In some embodiments, a first species containing Lewis acid sites or Lewis base sites and soluble in a solvent (e.g., water) is provided along with a second species containing Lewis base sites or Lewis acid sites (respectively) and insoluble in the solvent. This provides the option of providing an insoluble species as part of the positive electrode solid, which in turn provides a valuable level of flexibility in the manufacturing process of the positive electrode. Differences in solubility can inhibit premature interactions between the first and second species, which could otherwise lead to premature precipitation of an insoluble product with inhomogeneous or poor binding properties. The present disclosure recognizes that certain commonly used and available polymer salts, such as poly(diallyldimethylammonium chloride) (PDADMA-Cl), are actually water-soluble and, therefore, may result in such premature precipitation when used. By forming PDADMA with other counterions (or by using metathesis to replace chloride with alternative anions), the solubility of the PDADMA polymer can be adjusted, specifically to provide a water-insoluble PDADMA polymer. Such a water-insoluble PDADMA polymer can then be combined with a water-soluble polymer (e.g., an anionic polymer) during cathode processing to form an effective cathode binder. This approach of manipulating or altering the identity of the counterion can be applied to other commonly used and available polymer salts to alter their solubility (e.g., by substituting an anion to render the polymer salt water-insoluble).

[0008] The present disclosure further recognizes that batteries based on positive electrode active materials (e.g., sulfur) may offer higher performance when alternative (e.g., more polar) electrolyte solvents are used. However, many of these solvents cannot be used with positive electrodes that use conventional binders because they dissolve typical positive electrode binders, leading to physical destruction of the positive electrode film. For example, amide-based solvents such as n-methylpyrrolidone dissolve polyvinylidene fluoride (PVdF). Therefore, while it may be desirable to use amides as components of sulfur electrolytes to improve energy or power output, they cannot be substituted unless more resilient binders are developed. Certain binders disclosed herein are insoluble in amide-based solvents, allowing the use of such solvents in battery electrolytes with positive electrodes containing such binders. Generally, the binders disclosed herein allow for a wider selection of electrolytes than conventional binders.

[0009] In some aspects, the present disclosure is directed to electrode (e.g., positive electrode) compositions for (e.g., lithium-sulfur) batteries. The compositions may include an electrochemically active material and a binder. The binder may include chemically interacting Lewis acid and Lewis base sites.

[0010] In some embodiments, the binder comprises two different species, each containing either Lewis acid or Lewis base sites. In some embodiments, one of the two different species is a polymer (e.g., an ionomer) and the other of the two different species is a particle (e.g., a nanoparticle). In some embodiments, the particle is a silica particle, a metal oxide particle, a carbon particle, a metal sulfide particle, or a metal fluoride particle. In some embodiments, the particle is porous (e.g., mesoporous). In some embodiments, the two different species are different polymers (e.g., two ionomers). In some embodiments, one of the two different species is a cationic polymer and the other of the two different species is an anionic polymer.

[0011] In some embodiments, the binder in the composition forms a network of nodes, where the nodes are sites of chemical interaction between Lewis acid sites and Lewis base sites. In some embodiments, the binder comprises two different species, one of which contains Lewis acid sites and the other of which contains Lewis base sites.

[0012] In some embodiments, such binders are derived from a first species that contains either Lewis acid or Lewis base sites and is soluble in aqueous solvents, and a second species that is insoluble in aqueous solution and contains complementary Lewis basic or Lewis acidic sites, respectively (e.g., where the water-insoluble species is a particle (e.g., nanoparticle)). In some embodiments, the first (water-soluble) species contains Lewis acid sites, and the second (insoluble) species contains Lewis base sites. In certain such embodiments, the binder is introduced into the composition as an aqueous slurry containing a dissolved first (water-soluble) species and a second (water-insoluble) species that is a suspended solid (e.g., particle). In some embodiments, the soluble (first) species contains Lewis base sites, and the suspended solid (second) species contains Lewis acid sites (e.g., where the binder is introduced into the composition as a slurry containing a water-soluble Lewis base species and a water-insoluble Lewis acid species that is a particle). In some embodiments, the soluble (first) species comprises Lewis acid sites and the suspended solid (second) species comprises Lewis basic sites (e.g., where the binder is introduced into the composition as a slurry comprising water-soluble Lewis acid species and particulate water-insoluble Lewis basic species). In some embodiments, the binder is formed upon mixing of the water-soluble and water-insoluble species. In certain embodiments, the binder is formed upon full or partial drying of a slurry comprising a water-soluble Lewis acidic or basic species and a complementary water-insoluble Lewis acidic or basic species.

[0013] In some embodiments, a first species contains either Lewis acidic or Lewis basic moieties and is soluble in aqueous solvents, while a different second species contains the other of Lewis acidic and Lewis basic moieties and is insoluble in aqueous solutions (e.g., where the water-insoluble species is a particle (e.g., nanoparticle)). In some embodiments, the first species contains Lewis acidic moieties and is water-insoluble, and the second species contains Lewis basic moieties and is water-soluble (e.g., where the binder is introduced to the composition as a slurry containing a water-soluble second species and a water-insoluble first species that is a particle). In some embodiments, the binder contains a water-soluble portion and a water-insoluble portion that chemically interact with each other.

[0014] In some embodiments, the binder comprises particles containing only Lewis acid sites or only Lewis base sites. In some embodiments, the binder comprises a linear polymer containing only Lewis acid sites or only Lewis base sites. In some embodiments, the binder comprises one or more polymers having Lewis acid sites and / or Lewis base sites incorporated into the polymer backbone(s) in the form of functional groups. In some embodiments, the binder defines (e.g., forms) a supramolecular polymer network in the composition. In some embodiments, the binder comprises neutral species (e.g., containing boron, nitrogen, or phosphorus centers) containing Lewis acid sites or Lewis base sites.

[0015] In some embodiments, the binder comprises species that decorate the surface of the electrochemically active material, hi some embodiments, the electrochemically active material comprises particles and the binder comprises species that decorate the particles.

[0016] In some embodiments, the electrochemically active material comprises one or more elements selected from the group consisting of sulfur (e.g., sulfur in the form of an S8 cyclic eight-atom molecule), selenium, lithium sulfide (e.g., LiS and / or LiS), chalcogenides (e.g., metal sulfides), organosulfur, and alloys or mixtures of any two or more thereof.

[0017] In some embodiments, the composition includes an electronically conductive material (e.g., conductive carbon). In some embodiments, the binder includes a species that decorates the surface of the electronically conductive material. In some embodiments, particles include an electronically conductive material and the binder includes a species that decorates the particles (e.g., a Lewis acidic or Lewis basic species or functional group). In some embodiments, the electronically conductive material is a conductive carbon powder (e.g., carbon black, Super P®, C-NERGY™ Super C65, Ensaco® black, Ketjenblack®, acetylene black, synthetic graphite such as Timrex® SFG-6, Timrex® SFG-15, Timrex® SFG-44, Timrex® KS-6, Timrex® KS-15, Timrex® KS-44, natural flake graphite, graphene, carbon nanotubes, fullerenes, hard carbon, and / or mesocarbon microbeads).

[0018] In some embodiments, the provided binder comprises a member selected from the group of cationic polymers. In certain embodiments, the cationic polymer is a polymer containing ammonium groups (e.g., tetraalkylammonium groups). In certain embodiments, the cationic polymer is a polymer containing cationic heterocyclic groups (e.g., pyridinium, imidazolium, pyrrolidinium, etc.). In certain embodiments, the polymer comprises a poly(diallyldimethylammonium), poly(3-vinylimidazolium), or poly(pyridiniumphenylene) composition. The cationic polymer further comprises an anion to balance the positive charge. In certain embodiments, the cationic polymer is provided as a defined salt comprising one or more anions such as carboxylate, sulfonate, halide ion, anionic imide-type anion, phosphate, sulfate, sulfite, sulfide, borate, thiosulfate, thionate, thiocarboxylate, dithiocarbamate, nitrate, nitrite, xanthate, thiocarboxylate, dithiocarboxylate, carbonate, monothiocarbonate, dithiocarbonate, trithiocarbonate, fluorophosphate, thiophosphate, etc. In certain embodiments, such polymers are provided as defined salts with anions selected from trifluoroacetate, trifluoromethanesulfonate, 2-trifluoromethyl-4,5-dicyanoimidazole, bis(trifluoromethane)sulfonimide ("TFSI"), bisfluorosulfonamide ("FSI"), hexafluorophosphate, iodide, nitrate, acetate, and tetrafluoroborate. In certain embodiments, the cationic polymer is provided as a TFSI salt. In certain embodiments, the cationic polymer is provided as an FSI salt. In certain embodiments, the cationic polymer is provided as a PF6 salt. - In certain embodiments, the cationic polymer is BF4 -In certain embodiments, the cationic polymer is provided as an iodide salt. In certain embodiments, the anion associated with the provided cationic polymer may comprise a polyanionic species. Such polyanionic species may satisfy the multiple positive charges in the provided cationic polymer, or may be, for example, a metal ion (e.g., Li + ) or another organic cation. For example, the counterion in the provided cationic polymers may be LiCO3 - It could be.

[0019] In certain embodiments, the provided binder comprises a member selected from the group consisting of anionic polymers. In certain embodiments, such anionic polymers contain anionic functional groups (or functional groups that can be deprotonated to anionic groups), such as carboxylate, sulfonate, phosphate, borate, thionate, thiocarboxylate, carbamate, thiocarbamate, dithiocarbamate, xanthate, thiocarboxylate, dithiocarboxylate, carbonate, monothiocarbonate, dithiocarbonate, trithiocarbonate, fluorophosphate, thiophosphate, and borate, as well as derivatives, mixtures, and copolymers thereof. In certain embodiments, such polymers include polyacrylate, polymethacrylate, polystyrene sulfonate, modified polystyrene carboxylate, and carboxymethyl cellulose. In certain embodiments, the anionic polymer is provided as a defined salt with a cation. Suitable cations include H +, metal ions, and "onium" cations containing one or more nitrogen, sulfur, and / or phosphorus atoms. In certain embodiments, anionic polymers are provided as salts with metal cations. In certain embodiments, anionic polymers are provided as salts with alkaline earth metal cations (e.g., lithium, sodium, potassium, rubidium, or cesium). In certain embodiments, anionic polymers are provided as lithium salts. In certain embodiments, anionic polymers are provided as sodium salts. In certain embodiments, anionic polymers are provided as salts with alkali metals or transition metals. In certain embodiments, anionic polymers are provided as salts with organic cations, such as ammonium salts, phosphonium salts, or phosphazenium salts. In certain embodiments, such polymers are provided in protonated form.

[0020] In some embodiments, provided lithium-sulfur batteries include a positive electrode comprising an electrode composition disclosed herein (e.g., where the electrode composition is disposed as a coating on a current collector).

[0021] In some aspects, the present disclosure is directed to methods for making a composition (e.g., an electrode composition disclosed herein). The method may include combining components of a binder in a slurry (e.g., with an electrochemically active material). The components may include species that are soluble in the slurry and species that are insoluble in the slurry. The method may include chemically interacting the soluble and insoluble species to form a binder (e.g., one that binds the electrochemically active material).

[0022] In some embodiments, the soluble species comprises Lewis base sites or Lewis acid sites, and the insoluble species comprises Lewis acid sites or Lewis base sites, respectively. In some embodiments, chemically interacting comprises interacting Lewis acid sites with Lewis base sites. In some embodiments, the soluble species comprises Lewis base sites and the insoluble species comprises Lewis acid sites.

[0023] In some embodiments, the slurry is a water-based slurry. In some embodiments, the insoluble species is a particle or a linear polymer. In some embodiments, the soluble species is a polymer (e.g., a linear polymer).

[0024] In some embodiments, the method includes forming an insoluble species prior to combining, where forming the insoluble species includes performing metathesis (e.g., anion metathesis) with the precursor material (e.g., resulting in precipitation of the product (e.g., the insoluble species)). In some embodiments, the precursor material includes one or more materials including one or more first anions selected from the group consisting of trifluoroacetate, trifluoromethanesulfonate, 2-trifluoromethyl-4,5-dicyanoimidazole, bis(trifluoromethane)sulfonimide ("TFSI"), bisfluorosulfonamide ("FSI"), hexafluorophosphate, iodide, nitrate, acetate, and tetrafluoroborate. In certain embodiments, the one or more anions are selected to minimize their mass fraction in the product, thus achieving a higher mass content of cationic polymer units. In some embodiments, the metathesis is performed in water, and the insoluble species is insoluble in water. In some embodiments, the metathesis is carried out in a non-aqueous solvent and the insoluble species is insoluble in water.

[0025] In some embodiments, forming the insoluble species includes performing a second metathesis (e.g., anionic metathesis) (e.g., on the product obtained from the first metathesis) in a non-aqueous solvent (e.g., acetonitrile). In some embodiments, the second metathesis is performed using one or more materials including one or more second anions. In some embodiments, the one or more second anions are selected from the group consisting of tetrafluoroborate, hexafluorophosphate, iodide, nitrate, and bis(fluoro)sulfonamide. In some embodiments, the one or more first anions are different from the one or more second anions. In some embodiments, the one or more second anions are lighter than the one or more first anions. In some embodiments, the one or more first anions are TFSI and the one or more second anions are tetrafluoroborate. In some embodiments, the one or more first anions are TFSI and the one or more second anions are iodide. In some embodiments, the one or more first anions are TFSI and the one or more second anions are nitrate. In some embodiments, the one or more first anions are FSI and the one or more second anions are tetrafluoroborate. In some embodiments, the one or more first anions are FSI and the one or more second anions are tetrafluoroborate. In some embodiments, the one or more first anions are FSI and the one or more second anions are nitrate. In some embodiments, the method includes dissolving the resulting metathesis product (e.g., precipitate) in a non-aqueous solvent used to perform the second metathesis.

[0026] In some embodiments, the method includes decorating the electrochemically active material with an insoluble species prior to bonding. In some embodiments, the method includes forming an insoluble species, where forming the insoluble species includes performing metathesis in the presence of an electrochemically active material (e.g., particles of an electrochemically active material), and the decoration occurs during metathesis. In some embodiments, the metathesis is performed in water, and the electrochemically active material is water-insoluble (e.g., a carbon-sulfur active material). In some embodiments, the method includes forming an insoluble species, where forming the insoluble species includes performing a first metathesis followed by a second metathesis, where the subsequent second metathesis, but not the first metathesis, is performed in the presence of an electrochemically active material (e.g., particles of an electrochemically active material), and the decoration occurs during the second metathesis. In some embodiments, the electrochemically active material is soluble in a solvent used for the first metathesis and insoluble in a solvent used for the second metathesis. In some embodiments, the electrochemically active material is water-soluble. In some embodiments, the electrochemically active material comprises a metal sulfide.

[0027] In some embodiments, the method includes decorating the electronically conductive material (e.g., conductive carbon) with an insoluble species prior to bonding. In some embodiments, the method includes forming the insoluble species, where forming the insoluble species includes performing metathesis in the presence of an electrochemically active material (e.g., particles of an electrochemically active material), and the decoration occurs during metathesis. In some embodiments, the metathesis is performed in water, and the electronically conductive material is water-insoluble.

[0028] In some embodiments, the chemical interaction occurs at room temperature and / or in the ambient atmosphere. In some embodiments, the chemical interaction occurs spontaneously upon combining the components.

[0029] In some aspects, the present disclosure is directed to a method for preparing a species for use in a binder. The method may include performing metathesis to replace a counterion of the species such that the solubility of the species in a solvent changes from soluble to insoluble, or from insoluble to soluble. In some embodiments, the species changes from soluble to insoluble in the solvent. In some embodiments, the method includes performing metathesis in the presence of a material (e.g., particles of a material) such that the species decorates the material. In some embodiments, the method includes performing metathesis in the presence of a material (e.g., particles of a material) such that the species decorates the surface of the material. In some embodiments, the material is an electrochemically active material or an electronically conductive material.

[0030] In some aspects, the present disclosure is directed to a composite material comprising a material and a binder, wherein the binder comprises Lewis acid moieties and Lewis base moieties that chemically interact. In some embodiments, the composition comprises particles comprising the material, and the binder binds the particles together. In some embodiments, the composition is a film (e.g., a self-supporting film) (e.g., a coating on a substrate).

[0031] Any two or more of the features described herein, including this Abstract, may be combined to form embodiments of the present disclosure, whether or not they are specifically and explicitly described in this specification as separate combinations.

[0032] The present teachings described herein will be more fully understood from the following description of various exemplary embodiments when read in conjunction with the accompanying drawings. It should be understood that each of the drawings described below is for illustrative purposes only and is not intended to limit the scope of the present teachings in any way. The foregoing and other objects, aspects, features, and advantages of the present disclosure will become more apparent and may be better understood by reference to the following description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0033] [Figure 1A] 1 shows a schematic diagram of a supramolecular conjugate according to an exemplary embodiment of the present disclosure.

[0034] [Figure 1B] FIG. 1 shows a schematic diagram of a supramolecular binder comprising particle species according to an exemplary embodiment of the present disclosure.

[0035] [Figure 1C] FIG. 1 shows a schematic diagram of a supramolecular binder comprising particle species according to an exemplary embodiment of the present disclosure.

[0036] [Figure 1D] FIG. 1 shows a schematic diagram of a supramolecular binder comprising polymer species decorating particles of electrochemically active material, according to an exemplary embodiment of the present disclosure.

[0037] [Figure 1E] FIG. 1 shows a schematic diagram of a supramolecular binder comprising particle species decorating particles of electrochemically active material, according to an exemplary embodiment of the present disclosure.

[0038] [Figure 2A] 1 shows a flowchart of a method for forming a binder (e.g., forming an electrode including a binder) according to an exemplary embodiment of the present disclosure. [Figure 2B] 1 shows a flowchart of a method for forming a binder (e.g., forming an electrode including a binder) according to an exemplary embodiment of the present disclosure.

[0039] [Figure 3A] 1 shows a cross-sectional view of an electrochemical cell according to an exemplary embodiment of the present disclosure.

[0040] [Figure 3B] 1 shows a cross-sectional view of an electrochemical cell according to an exemplary embodiment of the present disclosure.

[0041] [Figure 4] FIG. 1 illustrates a perspective view of a cylindrical battery according to an exemplary embodiment of the present disclosure.

[0042] [Figure 5] 10 shows a plot of experimental rate ladder results for a cathode constructed using a binder according to an exemplary embodiment of the present disclosure.

[0043] [Figure 6] 1 shows a bar graph illustrating the number of cycles to 80% of the initial capacity for batteries constructed with the provided supramolecular binders versus batteries constructed with non-supramolecular binders. DETAILED DESCRIPTION OF THE INVENTION

[0044] Schematic drawings are not necessarily drawn to scale.

[0045] Disclosed herein are, inter alia, binders for use in electrochemical cells and methods of forming the binders. The binders may be used in electrode compositions of electrochemical cells, such as positive electrodes. For example, the binders may bind together a solid mixture of materials containing electrochemically active species (e.g., present in particulate form) into a structurally stable electrode film. The provided binders may include Lewis acid sites and Lewis base sites that chemically interact. The use of Lewis acid sites and Lewis base sites that chemically interact can eliminate the need for physical crosslinks (i.e., crosslinks having covalent bonds). In certain embodiments, the Lewis acid sites and Lewis base sites are present on different species (e.g., on different polymers or particles). A chemical interaction (e.g., ionic interaction) between the Lewis acid sites and the Lewis base sites may form to form the binder (e.g., during the formation of the electrode composition). Thus, the binder may include a network of nodes where the Lewis acid sites and the Lewis base sites chemically interact (e.g., ionically interact). In certain embodiments, the different species may have different solubilities in a solvent, e.g., one may be soluble and the other insoluble. The difference in solubility may delay the interaction between the Lewis acid and Lewis base sites and suppress premature precipitation of the supramolecular species. In some embodiments, provided binders define (e.g., form) a supramolecular network in the electrode composition. Such binders allow for the use of reduced amounts of binder (e.g., as measured by wt% binder in the electrode, surface area, vol% binder, or other indicators). In some embodiments, the bend radius test of electrodes prepared with binders disclosed herein may be improved over comparable electrodes prepared with conventional linear polymer binders. By providing a stronger binder that allows for the use of lower amounts without compromising cohesion, surface coverage of the electrode components held together by the binder, such as electrochemically active materials such as sulfur or metal sulfides, or electronically conductive materials such as conductive carbon, may be reduced.In some embodiments, reduced surface coverage of conductive carbon particles can be beneficial for higher performance batteries. Such reduced surface coverage may be achieved, for example, when one species in a provided binder is a particle. In some embodiments, the binder does not contain covalent crosslinks. In some embodiments, the binder may contribute to the ionic conductivity of the electrode.

[0046] Lewis acid sites and Lewis base sites are locations such as functional groups of species that act or can act as Lewis acids or Lewis bases, respectively. For example, a polymer may have Lewis acid sites or Lewis base sites incorporated into its polymer backbone (e.g., repeating units). Lewis acid sites in a polymer may be one or more functional groups that act as Lewis acids, or moieties formed from one or more functional groups. Lewis base sites in a polymer may be one or more functional groups that act as Lewis bases, or moieties formed from one or more functional groups. A first species may have only Lewis acid sites, and a different second species may have only Lewis base sites. The first species and the second species may both be polymers.

[0047] Generally, not all Lewis acid sites of a first species interact with all Lewis base sites of a second species. For example, if functional groups contained in, or sites formed from, repeat units of a polymer define Lewis acid sites or Lewis base sites, not all repeat units will chemically interact with the corresponding Lewis base sites or Lewis acid sites, respectively, on the second species. For example, given the coiled nature of linear polymers, this will clearly not be the case in all embodiments. In some embodiments, species containing Lewis acid sites or Lewis base sites are neutral. In some embodiments, species containing Lewis acid sites or Lewis base sites are ionic (e.g., ionic polymers or ionomers). As is well known in the art, under certain conditions, not all repeat units in an ionomer may be ionized. Thus, an ionomer may have only Lewis acid sites or Lewis base sites at ionized sites. When the Lewis acid sites or Lewis base sites of an ionomer are ionized, they can interact (e.g., via ionic interactions) with the Lewis base sites or Lewis acid sites of a different species, respectively.

[0048] The species containing Lewis acid or Lewis base sites can be, for example, a polymer or a particle. (A "particle" species can refer to a particulate material containing multiple particles (e.g., nanoparticles). Similarly, a "polymer" species can refer to a material or composition containing multiple individual polymer chains (e.g., linear chains).) The particle can be a polymer particle, formed, for example, by precipitating a polymer from a solution. In some embodiments, the particle is a silica particle, a metal oxide particle, a metal chalcogenide particle, a carbon particle, a metal fluoride particle, a metal sulfide particle, or a composite particle containing multiple types of materials. In some embodiments, any combination of silica particles, metal oxide particles, metal chalcogenide particles, carbon particles, metal fluoride particles, or composite particles can also be used in the binder. In some embodiments, the particle has a functionalized surface that provides Lewis acid or Lewis base sites. The particle can be porous, for example, mesoporous. Porous particles may facilitate increased chemical interaction between Lewis acid sites and Lewis base sites in the binder, for example, due to increased surface area, which exposes additional site(s). The particles may be nanoparticles. In some embodiments, the polymer species is a linear polymer. Different species of polymer (e.g., linear polymer) may be used in the binder. For example, two different ionomers may be used, such as a cationic polymer and an anionic polymer. In some embodiments, particles (e.g., polymeric particles or inorganic particles) containing Lewis acid sites or Lewis base sites are used in combination with a polymer (e.g., linear polymer) containing Lewis base sites or Lewis acid sites, respectively, to form a binder in which the Lewis acid sites and Lewis base sites chemically interact.

[0049] In some embodiments, provided binders include or result from interactions between a first species that contains either Lewis acid or Lewis base sites and is soluble in a solvent, such as water (or, alternatively, a non-aqueous solvent), and a different second species that contains Lewis base or Lewis acid sites, respectively, and may be insoluble in the solvent. In some embodiments, the water-insoluble species is a particle (e.g., a nanoparticle). In some embodiments, the particle is an inorganic, non-polymeric species, such as silica, metal oxide, metal chalcogenide, carbon, composite, or metal fluoride particles, and is therefore insoluble in the solvent. In some embodiments, provided binders include a water-soluble portion (e.g., a first species) and a water-insoluble portion (e.g., a different second species) that chemically interact. In certain embodiments, provided binders are an interacting network formed by two such species after the solvent in which the first species is soluble has been partially or completely removed.

[0050] The species containing Lewis acidic or Lewis basic sites (e.g., groups) can be polymers. Non-limiting examples of polymers containing Lewis acidic and Lewis basic sites are described in Progress in Polymer Science Vol. 111, December 2020, 101313 (doi.org / 10.1016 / j.progpolymsci.2020.101313), the entire contents of which are incorporated herein by reference.

[0051] The species containing Lewis acid sites may be a polymer, such as a cationic polymer. The cationic polymer may be provided in the slurry as a salt and then form a chemical interaction with a Lewis base site in another species, such as an anionic polymer (e.g., originally provided as a salt). The species containing Lewis acid sites (e.g., a polymer) may be insoluble in a solvent such as water. In some embodiments, the species containing Lewis acid sites is soluble in a solvent. The species containing Lewis acid sites may be particles, such as particles of a cationic polymer, or particles containing or coated with a cationic polymer, may be used in the binder. In certain embodiments, the cationic polymer is a polymer containing ammonium groups (e.g., tetraalkylammonium groups). In certain embodiments, the cationic polymer is a polymer containing cationic heterocyclic groups (e.g., pyridinium, imidazolium, pyrrolidinium, etc.). Examples of suitable polymers containing Lewis acid moieties include poly(diallyldimethylammonium), poly(3-vinylimidazolium), poly(pyridinium phenylene) compositions, and polymers containing one or more members selected from the group consisting of pyridinium, imidazolium, piperidinium, phosphonium, and pyrrolidinium (e.g., in the form of a salt). In certain embodiments, the cationic polymer contains anions to balance its positive charge. In certain embodiments, the cationic polymer is provided as a defined salt containing one or more anions, such as carboxylate, sulfonate, halide ion, anionic imide-type anion, phosphate, sulfate, sulfite, sulfide, borate, thiosulfate, thionate, thiocarboxylate, dithiocarbamate, nitrate, nitrite, xanthate, thiocarboxylate, dithiocarboxylate, carbonate, monothiocarbonate, dithiocarbonate, trithiocarbonate, fluorophosphate, thiophosphate, etc.In certain embodiments, such polymers are provided as defined salts with anions selected from trifluoroacetate, trifluoromethanesulfonate, 2-trifluoromethyl-4,5-dicyanoimidazole, bis(trifluoromethane)sulfonimide ("TFSI"), bisfluorosulfonamide ("FSI"), hexafluorophosphate, iodide, nitrate, acetate, and tetrafluoroborate. In certain embodiments, the cationic polymer is provided as a TFSI salt. In certain embodiments, the cationic polymer is provided as an FSI salt. In certain embodiments, the cationic polymer is PF6. - In certain embodiments, the cationic polymer is BF4 - In certain embodiments, the cationic polymer is provided as an iodide salt. In certain embodiments, the anion associated with the provided cationic polymer may comprise a polyanionic species. Such polyanionic species may satisfy the multiple positive charges in the provided cationic polymer, or may be, for example, a metal ion (e.g., Li + ) or another organic cation. For example, the counterion in the provided cationic polymers may be LiCO3 - It could be.

[0052] The species containing Lewis basic sites may be a polymer, for example, an anionic polymer. The anionic polymer may be provided in the slurry as a salt and then form a chemical interaction with Lewis acid sites in another species, such as a cationic polymer (e.g., originally provided as a salt, such as a halide salt, carboxylate salt, TFSI salt, or FSI salt). The species containing Lewis basic sites (e.g., a polymer) may be soluble in a solvent, such as water. In some embodiments, the species containing Lewis basic sites is insoluble in a solvent. The species containing Lewis basic sites may be particles, for example, particles containing anionic polymers (e.g., polymers containing one or more functional groups selected from carboxylate, sulfonate, phosphate, borate, thionate, thiocarboxylate, carbamate, thiocarbamate, dithiocarbamate, xanthate, thiocarboxylate, dithiocarboxylate, carbonate, monothiocarbonate, dithiocarbonate, trithiocarbonate, fluorophosphate, thiophosphate, and borate [or functional groups that can be deprotonated to these anionic groups], as well as derivatives, mixtures, and copolymers thereof, and combinations of any two or more thereof) may be used in the binder. In certain embodiments, such anionic polymers are linear polymers. In certain embodiments, such polymers include polyacrylate, polymethacrylate, polystyrene sulfonate, modified polystyrene carboxylate, and carboxymethyl cellulose. In certain embodiments, the anionic polymers are provided as defined salts with cations. Suitable cations include H +, metal ions, and "onium" cations containing one or more nitrogen, sulfur, and / or phosphorus atoms. In certain embodiments, anionic polymers are provided as salts with metal cations. In certain embodiments, anionic polymers are provided as salts with alkaline earth metal cations (e.g., lithium, sodium, potassium, rubidium, or cesium). In certain embodiments, anionic polymers are provided as lithium salts. In certain embodiments, anionic polymers are provided as sodium salts. In certain embodiments, anionic polymers are provided as salts with alkali metals or transition metals. In certain embodiments, anionic polymers are provided as salts with organic cations, such as ammonium salts, phosphonium salts, or phosphazenium salts. In certain embodiments, such polymers are provided in protonated form.

[0053] The provided binders may include neutral species containing Lewis acid or Lewis basic sites. The Lewis acid or Lewis basic sites may chemically interact (e.g., non-ionic interactions) with Lewis basic or Lewis acid sites, respectively, on another species in the binder. For example, in some embodiments, the Lewis acid-containing species (e.g., Lewis acidic polymer species) may include boron centers, and the Lewis basic species may interact with those boron centers in the binder. In some embodiments, the Lewis base-containing species (e.g., Lewis basic polymer species) may include neutral nitrogen or phosphorus centers, and the Lewis acidic species may interact with those centers in the binder.

[0054] Species containing Lewis acid sites or Lewis base sites may decorate the surface of an electrochemically active material. The electrochemically active material may be in the form of particles. Particles containing electrochemically active materials may be, for example, nanoparticles, microparticles, or a combination thereof. Particles containing electrochemically active materials may alternatively or additionally be microporous, mesoporous, nanoporous, or any combination thereof. Particles containing electrochemically active materials may include (e.g., are) flake-shaped, rod-shaped, tubular, ellipsoidal (e.g., spherical) particles, core-shell particles, or a combination thereof, and may be composites of two or more materials, one or more of which may contain Lewis acid sites or base sites. In some embodiments, species containing Lewis acid sites decorate the surface of an electrochemically active material, such as the surface of a particle of an electrochemically active material. Species insoluble in a solvent, such as water, may decorate the surface of an electrochemically active material, such as the surface of a particle of an electrochemically active material. The polymeric species may decorate the surface of an electrochemically active material, such as the surface of particles of the electrochemically active material. The particle species may decorate the surface of an electrochemically active material, such as the surface of particles of the electrochemically active material. In some embodiments, an insoluble species (e.g., a polymer or particle) decorates a particle comprising an electrochemically active material. In some embodiments, a species comprising Lewis acid sites or Lewis base sites, e.g., a species comprising Lewis acid sites, decorates a particle comprising an electrochemically active material. Thus, a species that is soluble and / or comprises Lewis acid sites or Lewis base sites, e.g., Lewis base sites, may form a binder with an insoluble and / or species that does not comprise Lewis base sites or Lewis acid sites, e.g., Lewis acid sites, that decorates the surface of an electrochemically active material (e.g., decorates the surface of particles of an electrochemically active material), respectively. In some embodiments, the surface of an electrochemically active material may be decorated during a metathesis reaction, as further described below.

[0055] Species containing Lewis acid or Lewis base sites may decorate the surface of an electronically conductive material, such as conductive carbon. Such electronically conductive materials may be in the form of particles. Particles containing electronically conductive materials may be, for example, nanoparticles, microparticles, or a combination thereof. Particles containing electronically conductive materials may alternatively or additionally be microporous, mesoporous, nanoporous, or any combination thereof. Particles containing electronically conductive materials may include (e.g., are) flake-shaped, rod-shaped, tubular, ellipsoidal (e.g., spherical) particles, core-shell particles, or a combination thereof. In some embodiments, species containing Lewis acid sites decorate the surface of an electronically conductive material, such as the surface of a particle of an electronically conductive material. In certain embodiments, such Lewis acid or Lewis base sites may be covalently bonded to the material itself when decorating the particle. For example, carbon (graphite, carbon black, graphene, or carbon nanotubes) may be functionalized with anionic or cationic functional groups that act as Lewis acids or Lewis salts that interact with complementary species to form nodes in the provided binder. A species that is insoluble in a solvent, such as water, may decorate the surface of an electronically conductive material, such as the surface of a particle of the electronically conductive material. A species that is a polymer may decorate the surface of an electronically conductive material, such as the surface of a particle of the electronically conductive material. A species that is a particle may decorate the surface of an electronically conductive material, such as the surface of a particle of the electronically conductive material. In some embodiments, an insoluble species (e.g., a polymer or a particle) decorates a particle comprising an electronically conductive material. In some embodiments, a species containing Lewis acid or Lewis base sites, such as a species containing Lewis acid sites, decorates a particle comprising an electronically conductive material. Thus, species that are soluble and / or that include Lewis acid sites or Lewis base sites, e.g., Lewis base sites, may form binders with species that are insoluble and / or that do not include Lewis base sites or Lewis acid sites, respectively, e.g., species that do not include Lewis acid sites and that decorate the surface of the electronically conductive material (e.g., decorate the surface of particles of the electronically conductive material) (e.g., decorate particles of the electronically conductive material).In some embodiments, as further described below, the surface of the electronically conducting material may be decorated during the metathesis reaction, hi some embodiments, the species decorate both the surface of the electrochemically active material and the surface of the electronically conducting material.

[0056] In some embodiments, the binder particle species at least partially (e.g., entirely) encompasses (e.g., surrounds) one or more particles of a material, such as an electrochemically active material or an electronically conductive material. In some embodiments, at least one particle of the binder particle species encompasses different particle species, such as a mixture of electrochemically active material particles and electronically conductive material particles. Such particle species may be, for example, polymer particles. For example, particles of poly(diallyldimethylammonium)bis(trifluoromethanesulfonyl)imide (PDADMA-TFSI) (a species having Lewis acid sites) have been observed to at least partially encompass many carbon particles. In some embodiments, the electrochemically active material particles and / or the electronically conductive material particles may protrude from the particles of the binder particle species. For example, such particles may be distributed on the surface (e.g., the outer surface, or, if porous, the inner surface) of the particles of the binder particle species. In some embodiments, the electrochemically active material particles and / or the electronically conductive material particles may alternatively or additionally be contained within the particles of the binder particle species. Such electrochemically active and / or electronically conductive material particles may still function as intended if the material of the particles of the particle species in the binder is suitable (e.g., ionically permeable and / or ionically conductive and / or electronically conductive). This may be particularly true for polymer particles having Lewis acid or Lewis base sites.

[0057] In certain embodiments, the binders provided comprise a combination selected from the non-limiting examples in Table 1. [Table 1]

[0058] FIG. 1A shows an example of a binder 100 formed from a first linear polymer species 102 and a second linear polymer species 104. The linear polymer species 102 has a number of representative Lewis base sites, labeled 108. The linear polymer species 104 has a representative Lewis acid site, labeled 106. The Lewis base sites 108 and the Lewis acid sites 106 chemically interact, as indicated by arrow 110. If a particular Lewis acid site and a particular Lewis base site are too far apart, there will be no significant interaction between them. The binder 100 may hold together particles of electrochemically active material. For simplicity, the electrochemically active material is not shown in FIG. 1A. In a full-scale drawing, particles of such electrochemically active material would generally be much larger than the individual polymer chains depicted. Also, FIG. 1A does not show any electronically conductive material, such as conductive carbon, if present. Furthermore, while only two linear polymer chains are shown for illustrative purposes, those skilled in the art will recognize that each chain can generally interact with one or more other chains to define a supramolecular network. Figure 1B shows a binder 100 similar to Figure 1A, except that species 102 is a linear polymer and species 104 is a polymer particle. Also shown in Figure 1B are representative Lewis acid moieties 106 and Lewis base moieties 108 that are not chemically interacting. Figure 1C shows a binder 100 similar to Figure 1B, except that the particles are non-polymeric particles, such as silica particles, metal oxide particles, or metal fluoride particles. Figure 1D shows an example in which species 104 is a polymer (e.g., a water-insoluble polymer) decorating the surface of particle 112, which may include an electrochemically active or electronically conductive material. Figure 1E shows an example in which species 104 is a particle (e.g., a water-insoluble particle) decorating the surface of particle 112, which may include an electrochemically active or electronically conductive material. 1D-1E, for simplicity, only one particle is shown, although many such particles are typically present. In some embodiments, some particles 112 comprise an electrochemically active material and some particles 112 comprise an electronically conductive material.

[0059] Electrode preparation Various known methods are available for fabricating electrodes for use in lithium batteries (e.g., lithium-sulfur batteries) using electrode compositions. In some embodiments, a slurry-based method is used, such as a slurry of a binder and an electrochemically active material (e.g., sulfur or a sulfur-containing material (e.g., particulate material) (e.g., engineered nanoparticles containing an electroactive sulfur composition)). In some embodiments, an electronically conductive material, such as conductive carbon, is also included in the slurry. In some embodiments, the binder is formed in the slurry from two or more species present or incorporated in the slurry. These slurries are typically in the form of viscous liquids formulated to facilitate downstream film-forming (e.g., coating) operations. Thorough mixing of the slurry can affect the quality of film formation and the effectiveness of drying operations, which can affect the performance and physical strength of the electrode. Suitable mixing equipment includes ball mills, magnetic stirrers, ultrasonicators, planetary mixers, high-speed mixers, homogenizers, universal mixers, static mixers, and the like. The liquid used to make the slurry can be one that homogeneously disperses the electrochemically active material, binder, and any conductive material and additive(s) present, and that evaporates easily. Suitable slurry liquids include, for example, N-methylpyrrolidone, acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, water, isopropyl alcohol, dimethylpyrrolidone, γ-butyrolactone, and the like. In some embodiments, the slurry is an aqueous slurry.

[0060] In some embodiments, the binder is formed by combining binder components together in a slurry. The components may include species that are soluble in the solvent of the slurry and species that are insoluble in the solvent. The formation of the binder may occur through chemical interaction between the soluble and insoluble species. Such chemical interaction may occur readily under ambient conditions (e.g., in the ambient atmosphere and / or at or near room temperature). Such chemical interaction may occur spontaneously upon combining. The soluble species may contain Lewis base sites or Lewis acid sites, and the insoluble species may contain Lewis acid sites or Lewis base sites, respectively, which may then chemically interact with each other. The slurry may be an aqueous slurry. In some embodiments, the soluble species is a polymer, such as a linear polymer. In some embodiments, the insoluble species is a particle or a polymer.

[0061] Commonly available precursor materials may not be suitable for forming supramolecular binders. Therefore, one or more metathesis reactions may be performed to replace the counterions of one or more polymeric species to make them suitable for use in forming supramolecular binders. In some embodiments, this involves replacing the counterions to change the solubility of the polymer salt in a solvent, e.g., from soluble to insoluble (e.g., in water).

[0062] In some embodiments, two metathesis reactions are performed to form a species for use in a binder. For example, in that case, substitution with a desired counterion preferably involves or requires one or more substitutions, and each substitution preferably occurs in a different solvent. Examples 1 and 2 below illustrate such examples. Multiple metathesis reactions may be performed to successively decrease the mass fraction of the counterion in the species and / or to achieve a desired solubility of the species in a particular solvent, such as water or an organic solvent like acetonitrile. In some embodiments, it is desirable to minimize the mass of the counterion of the species to enable the production of more binder for a given input mass. Thus, in some embodiments, multiple metathesis reactions are performed in which subsequent counterions (e.g., anions) are lighter than the initially substituted counterions from the preceding metathesis. For example, as in Examples 1 and 2, the first metathesis may substitute Cl counterions for TFSI to alter solubility, and a subsequent metathesis may substitute BF4 for TFSI (e.g., which may also alter solubility).

[0063] In some embodiments, prior to any combining, the electrochemically active material and / or the electronically conductive material (e.g., its surface(s)) is decorated with an insoluble species (e.g., a polymer or particulate species). In that way, a supramolecular network linking the electrochemically active material and / or the electronically conductive material may be formed upon combining the decorated material with a soluble species that chemically interacts with the insoluble species, e.g., through Lewis acid and base interactions between the species. The decoration may occur during metathesis performed to form the insoluble species. The metathesis may occur spontaneously.

[0064] When more than one metathesis is used, the electrochemically active material and / or the electronically conductive material may be added only during a subsequent metathesis, rather than during the first metathesis. Some electrochemically active materials are soluble in certain solvents. Therefore, if the first metathesis uses a solvent in which the material is soluble, it may not be feasible to decorate the material during the first metathesis. However, if the second metathesis uses a solvent in which the material is insoluble, decoration can be performed during the second metathesis. For example, some metal sulfide materials are soluble in water but insoluble in organic solvents such as acetonitrile. Therefore, such specific metal sulfide materials may be decorated during the second metathesis, which is preferably performed in an organic solvent. Electrochemically active carbon-sulfur materials may be insoluble in water and therefore do not require a second metathesis for decoration. Nevertheless, a second metathesis may be performed, for example, to reduce the weight of the counterion.

[0065] 2A-2B illustrate an embodiment of a method 200 for forming a binder. With particular reference first to FIG. 2A, optional step 202 involves performing metathesis to form insoluble species. Optional step 204 involves decorating the surface of the electrochemically active material with insoluble species (e.g., salts of a cationic polymer) (e.g., formed in optional step 202). Such decoration may occur during the metathesis reaction. In step 206, the insoluble species, electrochemically active material, and soluble species (e.g., salts of an anionic polymer) are combined in a slurry. In step 208, a binder is formed having the electrochemically active species dispersed throughout. Formation may occur spontaneously (e.g., upon addition of soluble species to a mixture of the electrochemically active material and insoluble species, or upon addition of the electrochemically active material and insoluble species to a solution of the soluble species). In optional step 210, an electrode film comprising the binder and electrochemically active material is coated, for example, onto a current collector.

[0066] FIG. 2B illustrates an embodiment of method 200 using pre-decoration. In the embodiment of method 200 according to FIG. 2B, insoluble species (e.g., insoluble particulate species) are pre-decorated onto the electrochemically active material. In step 206, the insoluble species, the electrochemically active material, and the soluble species are combined in a slurry. In step 208, a binder is formed having the electrochemically active species dispersed throughout. Formation may occur spontaneously (e.g., upon addition of the soluble species to a mixture of the electrochemically active material and the insoluble species, or upon addition of the electrochemically active material and the insoluble species to a solution of the soluble species). In optional step 210, an electrode film comprising the binder and the electrochemically active material is coated, for example, onto a current collector.

[0067] In some embodiments, the prepared composition is coated onto a current collector and dried to form an electrode. Specifically, the slurry is used to coat a conductor (e.g., a current collector) by uniformly spreading the slurry over the conductor and then, in certain embodiments, by roll pressing (e.g., calendaring) and / or heating to form an electrode. Generally, the matrix of electrochemically active material and, if present, the conductive material are bound and held onto the conductor by a binder. In certain embodiments, carbon particles, carbon nanofibers, or carbon nanotubes are dispersed in the matrix to improve electrical conductivity. Examples of conductive carbon include powders such as carbon black, Super P®, C-NERGY™ Super C65, Ensaco® black, and Ketjenblack®, acetylene black, synthetic graphite such as Timrex® SFG-6, Timrex® SFG-15, Timrex® SFG-44, Timrex® KS-6, Timrex® KS-15, and Timrex® KS-44, natural exfoliated graphite, carbon nanotubes, fullerenes, hard carbon, and / or mesocarbon microbeads. Alternatively or additionally, in certain embodiments, lithium ions (e.g., provided in the form of a salt) are dispersed in the matrix to improve lithium ion conductivity.

[0068] In certain embodiments, the current collector is selected from the group consisting of aluminum foil, copper foil, nickel foil, stainless steel foil, titanium foil, zirconium foil, molybdenum foil, nickel foam, copper foam, carbon paper, carbon, fiber sheet, polymer substrate coated with a conductive metal, and / or combinations thereof. Meshes of these metals may also be used for the current collector. Alternatively or additionally, a 3D structured current collector may be used.

[0069] Electrochemical cell containing a binder In some embodiments, the binders disclosed herein are used with (e.g., in) one or more electrodes of an electrochemical cell, such as a positive electrode, a negative electrode, or both a positive electrode and a negative electrode. The binder may hold together electrochemically active materials (e.g., particles including (e.g., consisting of) an electrochemically active material). In some embodiments, the binder also serves (e.g., also serves) to bind conductive carbon, if present, in the composition. The electrochemical cell may be a battery, such as a secondary battery. The positive electrode included in the battery may be a conversion positive electrode including an electrochemically active conversion material, such as in a lithium-sulfur battery or a sodium-sulfur battery. In some embodiments, the lithium-sulfur battery of the present disclosure includes a lithium negative electrode, a sulfur-based positive electrode, and an electrolyte that enables (e.g., lithium) ion transport between the negative electrode and the positive electrode. In certain embodiments, the battery includes an outer casing (e.g., a hard or soft casing) that surrounds the negative electrode, the positive electrode, the separator, and the electrolyte. In certain embodiments, the battery case includes a conductive negative end cover or tab in electrical communication with the negative electrode and a conductive positive end cover or tab in electrical communication with the positive electrode to facilitate charging and discharging via an external circuit. Various battery configurations may be used, such as, for example, cylindrical, coin, or pouch batteries. Figures 3A-B show exemplary electrochemical cells comprising the binders disclosed herein (e.g., used with one or more electrodes, such as the negative or positive electrode, or both).

[0070] FIG. 3A shows a cross-section of an electrochemical cell 300 according to an exemplary embodiment of the present disclosure. The electrochemical cell 300 includes a negative electrode 302, a positive electrode 304, a separator 306 interposed between the negative electrode 302 and the positive electrode 304, a container 510, and a fluid electrolyte 512 in contact with the negative electrode 302 and the positive electrode 304, respectively. Such a cell may optionally include additional electrode and separator layers 302a, 302b, 304a, 304b, 306a, and 306b. FIG. 3B is another perspective cross-sectional view of a representative cell stack, showing the negative electrode 302, the positive electrode 304, and the separator 306 interposed between the negative electrode 302 and the positive electrode 304. FIG. 3B also shows the layers including the electrode 304. Specifically, the layers include a current collector 304-1, a positive electrode layer 304-2 including a lithium-intercalated electrochemically active material, and a positive electrode layer 304-3 including a converted electrochemically active material. As shown, the lithium-intercalated electrochemically active material 304-2 is interposed between the current collector 304-1 and the positive electrode layer 304-3.

[0071] The negative electrode 302 (sometimes referred to herein as the anode) comprises a negative electrode electrochemically active material capable of accepting cations. Non-limiting examples of negative electrode electrochemically active materials for lithium-based electrochemical cells include Li metal, Si, Sn, Bi, In, and / or Li alloys such as Al alloys, Li4Ti5O 12 , hard carbon, graphitic carbon, metal chalcogenides, and / or amorphous carbon. According to some embodiments of the present disclosure, most (e.g., greater than 90 wt %) of the negative electrode electrochemically active material may initially be contained in the discharged positive electrode 304 (sometimes referred to herein as the cathode) when the electrochemical cell 300 is first fabricated, and thus the electrode electrochemically active material forms part of the first electrode 302 during the initial charging of the electrochemical cell 300.

[0072] Techniques for depositing electrochemically active materials on portions of the negative electrode 302 are described in U.S. Patent Publication No. 2016 / 0172660, and similarly U.S. Patent Publication No. 2016 / 0172661, the contents of each of which are incorporated herein by reference to the extent such content is not inconsistent with the present disclosure.

[0073] The negative electrode 302 and the positive electrode 304 may further include one or more electronically conductive additives, as described herein. According to some embodiments of the present disclosure, the negative electrode 302 and / or the positive electrode 304 further include one or more polymer binders, as described below.

[0074] 4 shows an example of a battery according to various embodiments described below. While a cylindrical battery is shown here for illustrative purposes, other types of configurations, including prismatic or pouch (laminated) batteries, may be used as desired. The exemplary Li battery 400 includes an anode 402, a cathode 404, a separator 406 interposed between the anode 402 and the cathode 404, an electrolyte (not shown) that impregnates the separator 406, a battery case 405, and a sealing member 408 that seals the battery case 405. It will be understood that the exemplary battery 400 may simultaneously embody multiple aspects of the present disclosure in various designs.

[0075] The present disclosure provides, in particular, secondary batteries comprising electrodes (e.g., positive electrodes) made using the compositions described herein, including, for example, the binders disclosed herein. Such secondary batteries include, for example, lithium-based batteries, such as lithium-ion batteries and lithium-sulfur batteries, as well as other batteries, such as sodium-sulfur batteries. In certain embodiments, such batteries comprise a lithium-containing negative electrode composition bound to a positive electrode composition provided by a lithium-conducting electrolyte. In some embodiments, such batteries also comprise additional components, such as a separator between the negative and positive electrodes, negative and positive current collectors, terminals capable of connecting the battery to an external load, and an outer packaging such as a flexible pouch or rigid metal container. In some embodiments, a lithium-sulfur battery comprises a sulfur-containing positive electrode comprising a binder disclosed herein, a lithium-containing negative electrode, and an electrolyte that ionically bonds the negative and positive electrodes. In some embodiments, the binders disclosed herein are used in electrodes included in electrochemical cells that are not batteries, such as fuel cells. Furthermore, the battery need not be a secondary cell. In some embodiments, the binder is included in an electrode of a primary cell.

[0076] negative electrode In certain embodiments, an electrochemical cell includes a negative electrode. For example, a lithium battery (e.g., a lithium-sulfur battery) may include a lithium negative electrode. In some embodiments, any lithium negative electrode suitable for use in a lithium-sulfur battery may be used. In certain embodiments, the negative electrode of a lithium-sulfur battery includes a negative electrochemically active material selected from a material in which lithium insertion occurs reversibly, a material that reacts with lithium ions to form a lithium-containing compound, metallic lithium, a lithium alloy, and combinations thereof. In certain embodiments, the negative electrode includes metallic lithium. In certain embodiments, the lithium-containing negative electrode composition includes a carbon-based compound. In certain embodiments, the carbon-based compound is selected from the group consisting of crystalline carbon, amorphous carbon, graphite, and mixtures thereof. In certain embodiments, the material that reacts with lithium ions to form a lithium-containing compound is selected from the group consisting of tin oxide (SnO), titanium nitrate, and silicon. In certain embodiments, the lithium alloy includes an alloy of lithium with another alkali metal (e.g., sodium, potassium, rubidium, or cesium). In certain embodiments, the lithium alloy includes an alloy of lithium with a transition metal. In certain embodiments, the lithium alloy comprises an alloy of lithium with a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, Sn, and combinations thereof. In certain embodiments, the lithium alloy comprises an alloy of lithium with indium. In certain embodiments, the negative electrode comprises a lithium-silicon alloy. Examples of suitable lithium-silicon alloys include Li 15 Si4, Li 12 Si7, Li7Si3, Li 13 Si4 and Li 21 Si5 / Li 22 Examples of suitable lithium metal or lithium alloys include Si5. In certain embodiments, the lithium metal or lithium alloy is present as a composite with another material. In certain embodiments, such compositions include materials such as graphite, graphene, metal sulfides or oxides, or conductive polymers.

[0077] The negative electrode may be protected from redox shuttle reactions and dangerous runaway reactions by any methodology reported in the art, for example, by forming a protective layer on the surface of the negative electrode by chemical passivation or polymerization. For example, in certain embodiments, the negative electrode comprises an inorganic protective layer, an organic protective layer, or a mixture thereof, on the surface of lithium metal. In certain embodiments, the inorganic protective layer is selected from the group consisting of C, Ag, Sb, Mg, Al, Bi, Sn, Pb, Cd, Si, In, Ga, Li7La3Zr2O 12 (LLZO, Garnet), Li 1+x Al x Ge 2-x (PO4)3(LAGP), LiPON, Li 1+x Al x The organic protective layer may comprise Ti2(PO4)3(LATP), lithium silicate, lithium borate, lithium phosphate, lithium phosphide nitride, lithium silicon sulfide, lithium boron sulfide, lithium aluminum sulfide, lithium phosphate sulfide, lithium fluoride, or a combination thereof. In certain embodiments, the organic protective layer comprises a conductive monomer, oligomer, or polymer selected from poly(p-phenylene), polyacetylene, poly(p-phenylene vinylene), polyaniline, polypyrrole, polythiophene, poly(2,5-ethylene vinylene), acetylene, poly(perinaphthalene), polyacene, and poly(naphthalene-2,6-di-yl), or a combination thereof.

[0078] Furthermore, in certain embodiments, during charging and discharging of a lithium-sulfur battery, inert sulfur material generated from the electroactive sulfur material of the positive electrode is deposited on the surface of the negative electrode. As used herein, the term "inert sulfur" refers to sulfur that has become inactive as a result of repeated electrochemical and chemical reactions, such that it cannot participate in the electrochemical reactions of the positive electrode. In certain embodiments, the inert sulfur on the surface of the negative electrode acts as a protective layer for such an electrode. In certain embodiments, the inert sulfur is lithium sulfide.

[0079] Negative-electrode-free (e.g., no-anode) configurations are also contemplated. In negative-electrode-free configurations, a current collector is provided in place of a negative electrode, and electrochemically active species, such as lithium in a lithium-sulfur battery, are deposited on the surface of the current collector during the first electrochemical cycle (or the first few electrochemical cycles). Such lithium may come from the electrolyte and / or one or more additives within the electrochemical cell. The surface of the current collector then serves as a lithium source during further electrochemical cycles.

[0080] It is further contemplated that the present disclosure may be adapted for use in sodium-sulfur batteries. Such sodium-sulfur batteries include sodium-based negative electrodes and are encompassed within the scope of the present disclosure.

[0081] positive electrode In certain embodiments, an electrochemical cell includes a positive electrode. The positive electrode generally includes an electrochemically active material and a binder. In some embodiments, the positive electrode further includes an electronically conductive material, such as conductive carbon. Certain compositions disclosed herein may be applied to a current collector to form the positive electrode of an electrochemical cell, such as a battery. In some embodiments, the positive electrode is "carbon-free" (relatively carbon-free, e.g., having a carbon content of not more than 10 wt.%, a carbon content of not more than 5 wt.%, a carbon content of not more than 4 wt.%, a carbon content of not more than 3 wt.%, a carbon content of not more than 2 wt.%, a carbon content of not more than 1 wt.%, or a carbon content of not more than 0.5 wt.%). In some embodiments, the positive electrode includes conductive carbon. The positive electrode may include one or more additives. For example, in certain embodiments, provided positive electrode compositions may include 3D-structured graphene (e.g., as described in U.S. Pat. No. 11,299,397). In certain embodiments, the provided compositions have satisfactory electrical conductivity to provide a positive electrode with a low resistance path for electrons to access such a fabricated positive electrode. In various embodiments, other additives are included in the compositions to modify or otherwise enhance a positive electrode fabricated according to the principles described herein. Other positive electrode components include, for example, current collectors, connection tabs, etc.

[0082] In certain embodiments, the positive electrode (electrode) composition includes a non-carbon-based electrochemically active material (e.g., an intercalation material) and / or a sulfur-based electrochemically active material. The sulfur-based electrochemically active material may include sulfur in the form of an S8 cyclic molecule, sulfur in the form of lithium sulfide (e.g., Li2S2 and / or Li2S), or sulfur in the form of an electroactive organosulfur compound or an electroactive sulfur-containing polymer, or a combination thereof. In certain embodiments, the electrochemically active material is an intercalation material structured to intercalate lithium ions. In certain embodiments, the electrochemically active material has a voltage range that overlaps the discharge voltage range of S8→Li2S (conversion of sulfur to lithium sulfide), e.g., Li / Li + about 1.8V to about 2.6V for Li / Li +It operates at approximately 2.0V to 2.4V.

[0083] In certain embodiments, the electrochemically active material includes a combination of a sulfur-based electroactive material (e.g., elemental sulfur, LiS, an organosulfur compound, or a polymer) and one or more metal sulfides. In certain embodiments, the one or more metal sulfides include one or more of TiS, LiTiS (LTS), MoS, MoS, VS, TaS, NbSe, or a mixture of any two or more thereof. In certain embodiments, the electrochemically active material includes a combination of sulfur and TiS. In certain embodiments, the electrochemically active material includes a combination of lithium sulfide and TiS. In certain embodiments, the electrochemically active material includes a combination of sulfur and VS. In certain embodiments, the electrochemically active material includes a combination of lithium sulfide and VS. In certain embodiments, the electrochemically active material includes a combination of sulfur and MoS. In certain embodiments, the electrochemically active material includes a combination of lithium sulfide and Mo. In certain embodiments, when the electrochemically active material comprises a mixture of sulfur and a metal sulfide, the mixture has a sulfur:metal sulfide ratio of between about 1:5 and about 10:1. In certain embodiments, when the electrochemically active material comprises a mixture of sulfur and a metal sulfide, the mixture has a sulfur:metal sulfide ratio in the range of 1:5 to 10:1, e.g., about 1:5, about 1:2, about 1:1, about 2:1, about 3:1, about 5:1, or about 10:1.

[0084] In certain embodiments, the electrochemically active material includes one or more chalcogenides. In certain embodiments, the chalcogenide has at least one chalcogen anion (oxygen, sulfur, selenium, tellurium, or polonium anion) and at least one electropositive element. In certain embodiments, the one or more chalcogenides may be sulfide-based, selenium-based, or tellurium-based. In certain embodiments, the one or more chalcogenides include a metal sulfide. In certain embodiments, the one or more chalcogenides include one or more of TiS3, LiTiS2 (LTS), MoS2, Mo6S8, VS2, TaS2, and NbSe3. In certain embodiments, the one or more chalcogenides include a transition metal oxide and / or a polyanionic compound. In certain embodiments, the one or more chalcogenides include a metal monochalcogenide having a formula MX, where M is a transition metal and X is S, Se, or Te. In certain embodiments, the one or more chalcogenides comprise at least one transition metal dichalcogenide (TMD) of formula MX2, where M is a transition metal (e.g., Ti, V, Co, Ni, Zr, Nb, Mo, V, Tc, Rh, Pd, Hf, Ta, W, Re, Ir, or Pt) and X is S, Se, or Te. ... lithiated material having a layered crystal structure (e.g., TiS2, CoO2, NiO2, MnO2, Ni 0.33 Mn 0.33 Co 0.33 O2, Ni 0.8 Co 0.15 Al 0.05 In certain embodiments, the one or more chalcogenides include lithiated derivatives of materials having a layered crystal structure (e.g., LiTiS2, LiCoO2, LiNiO2, LiMnO2, LiNiO3), materials having a spinel crystal structure (e.g., Mn2O4 or Co2O4), materials having an olivine crystal structure (e.g., FePO4, MnPO4, or CoPO4), and / or materials having a tavorite crystal structure (e.g., FeSO4F or VPO4F). In certain embodiments, the one or more chalcogenides include lithiated derivatives of materials having a layered crystal structure (e.g., LiTiS2, LiCoO2, LiNiO2, LiMnO2, LiNi 0.33 Mn 0.33 Co 0.33 O2, LiNi 0.8 Co 0.15 Al0.05 Lithium derivatives of materials having a spinel crystal structure (e.g., LiMnO2, or Li2MnO3), lithiated derivatives of materials having a spinel crystal structure (e.g., LiMn2O4 or LiCo2O4), lithiated derivatives of materials having an olivine crystal structure (e.g., LiFePO4, LiMnPO4, or LiCoPO4), and / or lithiated derivatives of materials having a tavorite crystal structure (e.g., LiFeSO4F or LiVPO4F).

[0085] In certain embodiments, the one or more non-carbon, non-sulfur based electrochemically active materials are characterized by having high electronic conductivity. For example, the non-carbon, non-sulfur based electrochemically active material(s) may have a conductivity of about 10 -3 mS / cm 2 Super, about 0.01mS / cm 2 Super, about 0.05mS / cm 2 Super, about 0.1mS / cm 2 Super, about 0.5mS / cm 2 Greater than or about 1 mS / cm 2 It may have a conductivity of greater than 1000kJ / cm.

[0086] In certain embodiments, the positive electrode composition includes a conductive material and a binder. In certain embodiments, the conductive material includes a conductive material that facilitates electron movement within the composition. For example, in certain embodiments, the conductive material is selected from the group consisting of carbon-based materials, graphite-based materials, conductive polymers, metals, semiconductors, metal oxides, metal sulfides, and combinations thereof, with non-carbon-based materials being preferred.

[0087] In certain embodiments, the positive electrode further comprises a coating layer, for example, in certain embodiments, the coating layer comprises a polymer, an organic material, an inorganic material, or a mixture thereof that is not an integral part of the porous composite material or the current collector.

[0088] In certain embodiments, the positive electrode comprises one or more of the following features: (a) a "stack" of multifunctional materials (e.g., particles with gradient structures that balance ion and electron transport for, e.g., improved power capability, energy density, and lifetime; bifunctional positive electrode additives that simultaneously store Li and conduct electrons, replacing expensive and space-consuming carbon; binding molecules that spatially confine the energy-storing electrochemical reaction, thereby extending lifetime; electrolyte components that improve the base efficiency of the electrolyte and enhance energy density; and / or higher (b) dense electrode layers; (c) dense tertiary structures; (d) porosity control; (e) core-shell structures; (f) cross-linked polymer shells; (g) self-doped polymer shells; (h) ion-conducting binders; (i) bilayer hybrid cathodes; (j) polysulfide-trapping polymers; (k) high-surface-area three-dimensional structures (e.g., to retain, e.g., intercalate, both carbon and lithium); and (l) three-dimensional structures in which carbon is replaced by metal disulfides (e.g., and the battery includes a polymer electrolyte for sulfur).

[0089] isolation material In certain embodiments, an electrochemical cell (e.g., a lithium-sulfur battery) includes a separator that physically separates the negative electrode and positive electrode. In certain embodiments, the separator is a material that is substantially or completely impermeable to the electrolyte. In certain embodiments, the separator is impermeable to polysulfide ions dissolved in the electrolyte. In certain embodiments, the separator is entirely impermeable to the electrolyte such that the passage of electrolyte-soluble sulfides is blocked. In some embodiments, a degree of ionic conductivity across the separator is provided, for example, through interstices in such separator. In certain such embodiments, the separator as a whole, as a result of its impermeability, inhibits or limits the passage of electrolyte-soluble sulfides between the negative and positive electrode portions of the battery. In certain embodiments, the impermeable material separator is configured to allow lithium ion transport between the negative and positive electrodes of the battery during charging and discharging of the battery. In some such embodiments, the separator does not completely isolate the negative and positive electrodes from each other. One or more electrolyte-permeable channels that bypass or penetrate the impermeable surfaces of the separator should be provided to allow sufficient lithium ion flux between the anode and cathode portions of the battery. In some embodiments, when the separator itself is completely impermeable, the channels are provided through an annulus between the periphery of the separator and the wall of the battery case.

[0090] Those skilled in the art will appreciate that the optimum separator dimensions should balance the conflicting requirements of allowing sufficient lithium ion flux while providing maximum impedance to polysulfide migration. Apart from this, the shape and orientation of the separator are not particularly limited and will depend in part on the battery configuration. For example, the separator may be substantially circular for coin-type batteries or substantially rectangular for pouch-type batteries. As described herein, the separator surface may be void-free, with lithium ion flux occurring only around the edges of the impermeable sheet. However, certain embodiments are contemplated in which some or all of the required lithium ion flux is provided through the voids in the separator. In some embodiments, the separator is substantially flat. However, this does not exclude that curved or other non-planar configurations may be used.

[0091] The separator can be of any suitable thickness. To maximize the energy density of the battery, it is generally preferred that the separator be as thin and lightweight as possible. However, the separator should be thick enough to provide sufficient mechanical robustness and ensure adequate impermeability. In certain embodiments, the separator has a thickness of about 1 micron to about 200 microns, preferably about 5 microns to about 100 microns, and more preferably about 10 microns to about 30 microns.

[0092] electrolyte In certain embodiments, the lithium-sulfur battery includes an electrolyte comprising an electrolyte salt, such as lithium bis(trifluoromethanesulfonyl)imide, lithium triflate, lithium perchlorate, LiPF, lithium bis(fluoro)sulfonylimide (LiFSI), lithium iodide, lithium nitrate, LiBF, tetraalkylammonium salts (e.g., tetrabutylammonium tetrafluoroborate, TBABF), and salts that are liquid at room temperature (e.g., imidazolium salts, such as 1-ethyl-3-methylimidazolium bis-(perfluoroethylsulfonyl)imide, EMIBeti).

[0093] In certain embodiments, the electrolyte includes one or more alkali metal salts. In certain embodiments, such salts include lithium salts, such as LiCF3SO3, LiClO4, LiNO3, LiPF6, LiFSI, LiI, LiBF4, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), or combinations thereof. In certain embodiments, the electrolyte includes an ionic liquid, such as 1-ethyl-3-methylimidazolium-TFSI, N-butyl-N-methylpiperidinium-TFSI, N-methyl-n-butylpyrrolidinium-TFSI, N-methyl-N-propylpiperidinium-TFSI, 1-ethyl-3-methylimidazolium-FSI, N-butyl-N-methylpiperidinium-FSI, N-methyl-n-butylpyrrolidinium-FSI, N-methyl-N-propylpiperidinium-TFSI, or combinations thereof. In certain embodiments, the electrolyte comprises a superionic conductor, such as a sulfide, a selenide, an oxide, a phosphide, and a phosphate, such as phosphorus pentasulfide, or a combination thereof.

[0094] In certain embodiments, the electrolyte is a liquid. For example, in certain embodiments, the electrolyte comprises an organic solvent. In certain embodiments, the electrolyte comprises only one organic solvent. In some embodiments, the electrolyte comprises a mixture of two or more organic solvents. In certain embodiments, the mixture of organic solvents comprises organic solvents from at least two groups selected from weakly polar solvents, strongly polar solvents, and lithium-protective solvents.

[0095] As used herein, the term "weakly polar solvent" is defined as a solvent capable of dissolving elemental sulfur and having a dielectric constant of less than 15. In some embodiments, the weakly polar solvent is selected from aryl compounds, bicyclic ethers, and acyclic carbonate compounds. Non-limiting examples of weakly polar solvents include xylene, dimethoxyethane, 2-methyltetrahydrofuran, diethyl carbonate, dimethyl carbonate, toluene, dimethyl ether, diethyl ether, diglyme, tetraglyme, and the like. As used herein, the term "strongly polar solvent" is defined as a solvent capable of dissolving lithium polysulfide and having a dielectric constant of 15 or greater. In some embodiments, the strong polar solvent is selected from bicyclic carbonate compounds, sulfoxide compounds, lactone compounds, ketone compounds, ester compounds, sulfate ester compounds, and sulfite ester compounds. Non-limiting examples of strong polar solvents include hexamethylphosphoric triamide, γ-butyrolactone, acetonitrile, ethylene carbonate, propylene carbonate, N-methylpyrrolidone, 3-methyl-2-oxazolidone, dimethylformamide, sulfolane, dimethylacetamide, dimethyl sulfoxide, dimethyl sulfate, ethylene glycol diacetate, dimethyl sulfite, ethylene glycol sulfite, etc. As used herein, the term "lithium protecting solvent" is defined as a solvent that forms a good protective layer on the lithium surface, i.e., a stable solid-electrolyte interface (SEI) layer, and exhibits a cycling efficiency of at least 50%. In some embodiments, the lithium protecting solvent is selected from saturated ether compounds, unsaturated ether compounds, and heterocyclic compounds containing one or more heteroatoms selected from the group consisting of N, O, and / or S. Non-limiting examples of lithium protecting solvents include tetrahydrofuran, 1,3-dioxolane, 3,5-dimethylisoxazole, 2,5-dimethylfuran, furan, 2-methylfuran, 1,4-oxacyclohexane, 4-methyldioxolane, and the like.

[0096] In certain embodiments, the electrolyte is a liquid (e.g., an organic solvent). In some embodiments, the liquid is selected from the group consisting of organic carbonates, ethers, sulfones, water, alcohols, fluorocarbons, or any combination thereof. In certain embodiments, the electrolyte comprises an ether solvent.

[0097] In certain embodiments, the organic solvent comprises an ether. In certain embodiments, the organic solvent is selected from the group consisting of 1,3-dioxolane, dimethoxyethane, diglyme, triglyme, γ-butyrolactone, γ-valerolactone, and combinations thereof. In certain embodiments, the organic solvent comprises a mixture of 1,3-dioxolane and dimethoxyethane. In certain embodiments, the organic solvent comprises a 1:1 v / v mixture of 1,3-dioxolane and dimethoxyethane. In certain embodiments, the organic solvent is selected from the group consisting of diglyme, triglyme, γ-butyrolactone, γ-valerolactone, and combinations thereof. In certain embodiments, the electrolyte comprises sulfolane, sulfolene, dimethyl sulfone, or methyl ethyl sulfone. In some embodiments, the electrolyte comprises ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, or methyl ethyl carbonate.

[0098] In certain embodiments, the electrolyte comprises a liquid (e.g., an organic solvent). In some embodiments, the liquid is selected from the group consisting of organic carbonates, ethers, sulfones, water, alcohols, fluorocarbons, or any combination thereof. In certain embodiments, the electrolyte comprises an ether solvent. In certain embodiments, the electrolyte comprises a liquid selected from the group consisting of sulfolane, sulfolene, dimethyl sulfone, and methyl ethyl sulfone. In certain embodiments, the electrolyte comprises a liquid selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0099] In certain embodiments, the electrolyte is solid. In certain embodiments, the solid electrolyte comprises a polymer. In certain embodiments, the solid electrolyte comprises a glass, a ceramic, an inorganic composite, or a combination thereof. In certain embodiments, the solid electrolyte comprises a polymer composite with a glass, a ceramic, an inorganic composite, or a combination thereof. In certain embodiments, such solid electrolytes include one or more liquid components as plasticizers or to form a "gel electrolyte."

[0100] Other uses The preceding description has focused on the use of binders in the context of electrodes for electrochemical cells. However, the use of binders disclosed herein is not so limited. For example, binders may be used to bind other particulate or non-particulate materials together. Similar embodiments to those explicitly described above are also contemplated in which the electrochemically active material is instead some other, otherwise equivalent material. In some embodiments, binders disclosed herein are used in composite materials to bind materials together. The materials may be particulate, e.g., having the form of flakes, rods, tubes, or spherical particles. The materials may be nanoparticles. The composite material may be a film. The film may be self-supporting or a coating on a substrate. [Example]

[0101] In order that this application may be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes and are not to be construed as limiting in any manner.

[0102] Example 1: Preparation of PDADMA-TFSI polymer This example describes the synthesis of a species that can be used as a binder. In this case, the species is a water-insoluble cationic polymer in the salt form. First, 30 g of a 20 wt% aqueous solution of poly(diallyldimethylammonium chloride) (PDADMAC) (molecular weight 400-500 K (g / mol)) was diluted with 150 mL of deionized water in a beaker and stirred until homogeneous. In a separate beaker, 12.82 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) was dissolved in 20 mL of deionized water and poured into the polymer solution over approximately 5 minutes while stirring at 800 rpm with a magnetic stir bar. A white precipitate immediately formed, accompanied by an increase in the viscosity of the mixture, indicating metathesis of the chloride with TFSI. After addition, the beaker was covered with aluminum foil to prevent scattering and evaporation, and the mixture was stirred at 500 rpm at room temperature overnight. The mixture was then filtered through a filter flask and filter paper on a ceramic filter, washing with 1 L of deionized water. The white product was further dried by drawing air over it until loose particles formed, and then dried overnight at 65°C and then at 115°C overnight. Finally, 13 g of an off-white solid PDADMA-TFSI product was obtained.

[0103] Example 2: Preparation of sulfur-metal sulfide (SMS) / PDADMA-BF4 polymer composite This example describes the synthesis of a species that can be used as a binder. The polymer particle species in this case is a water-insoluble, acetonitrile-insoluble cationic polymer in the form of a salt. First, 1.193 g of poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMA-TFSI) polymer was dissolved in 50 mL of anhydrous acetonitrile in a 500 mL polypropylene centrifuge tube in a humidity-controlled dry chamber. Next, 9.375 g of a black solid sulfur-titanium disulfide (SMS) physical mixture (weight ratio: S:TiS2 = 70:30) was added in small increments, followed by an additional 50 mL of anhydrous acetonitrile. The centrifuge tube was sealed and mixed ultrasonically for 10 minutes, followed by 10 minutes of stirring with a magnetic stir bar. In a separate beaker, 2.5 g of lithium tetrafluoroborate (LiBF4) was dissolved in 20 mL of anhydrous acetonitrile, and half of the resulting solution was added dropwise to the mixture in the centrifuge tube (containing the polymer-SMS). The reaction mixture was sonicated for 10 minutes and then stirred for 10 minutes. The remaining LiBF4 solution was added and mixed in the same manner, and the reaction vessel was sealed and stirred overnight at room temperature. The mixture was centrifuged at 8000 rpm for 20 minutes, and the clear supernatant was decanted and discarded. 100 mL of anhydrous acetonitrile was then added to the remaining black solid, sonicated and mixed for 10 minutes, and then stirred for 10 minutes. The centrifugation was repeated, and the clear supernatant was decanted and discarded. The black solid product was dried in a vacuum oven at 65°C overnight. Finally, 6 g of PDADMA-BF4 product was obtained. Without wishing to be bound by any particular theory, the black appearance of the product suggests that SMS was dispersed in the PDADMA-BF4 product, and that PDADMA-BF4 decorated the SMS.

[0104] Example 3: Preparation of carbon-sulfur-based electroactive material / PDADMAT composite This example describes the synthesis and testing of a positive electrode using a binder. Following procedures substantially similar to those described in Examples 1 and 2, a carbon-sulfur-based electrochemically active material decorated with PDADMAT was constructed by suspending the active material in water and precipitating the PDADMAT. A positive electrode was then formed from a water-alcohol slurry containing the PDADMAT-decorated active material and tested. The capacity of the resulting positive electrode was tested using a "rate ladder" procedure, and the results are plotted in Figure 5. Example 4: Preparation of a positive electrode using a "supramolecular" binder Example 4a: Preparation of sulfur metal sulfide cathode using supramolecular binder (sulfur metal sulfide x PDADMA-TFSI / sodium polyacrylate) A mixture of 1-propanol, an aqueous solution containing sodium polyacrylate (PAA-Na), and conductive carbon was mixed in a FlackTek SpeedMixer™ to form a slurry. Acetonitrile and a powder containing 70 wt% sulfur and 30 wt% TiS2 were added at intervals until the desired mass fraction of electroactive material was present. A predetermined mass fraction of polydiallyldimethylammonium bis(trifluoromethanesulfonyl)imide powder was then added along with additional acetonitrile. The slurry was thoroughly mixed and cast onto a carbon-coated aluminum foil to form a positive electrode film. The positive electrode was dried under ambient conditions for 2 hours and then placed in a vacuum oven at 60 °C overnight. The final total solids loading of the resulting positive electrode film was 8.3-9.3 mg / cm. 2 It was. Example 4b: Preparation of carbon-sulfur composite cathode using supramolecular binder (CMD, PDADMA-TFSI / sodium polyacrylate) A mixture of 1-propanol, aqueous PAA-Na solution, and conductive carbon was mixed in a FlackTek SpeedMixer™ to form a slurry. Acetonitrile and a powder containing 80% sulfur and 20% carbon were added at intervals. A measured amount of polydiallyldimethylammonium bis(trifluoromethanesulfonyl)imide powder was then added along with additional acetonitrile to achieve the desired mass fraction. After thorough mixing, the slurry was cast onto a carbon-coated aluminum foil using a doctor blade and allowed to dry at ambient conditions for 2 hours before being placed in a vacuum oven at 60°C overnight. The final total solids loading of the completed cathode film was 8.2-9.2 mg / cm. 2 It was. The weight percent of the Lewis acid and Lewis base components in the cathode films prepared according to the above procedure was varied to evaluate the effect of different ratios of the two components. Representative compositions evaluated are listed in the legend to Figure 6. Example 5: Preparation of positive electrodes using comparative prior art binders Example 5a: Preparation of sulfur metal sulfide positive electrode using PAA binder (sulfur metal sulfide sodium polyacrylate) A mixture of ethanol, aqueous PAA-Na solution, and conductive carbon was mixed in a FlackTek SpeedMixer™ to form a slurry. Ethanol and powder containing 70 wt. % sulfur and 30 wt. % TiS2 were added at intervals. The slurry was cast onto a carbon-coated aluminum foil to form a positive electrode film. The positive electrode was dried at ambient conditions for 2 hours and then placed in a vacuum oven at 60 °C overnight. The final total solids loading of the completed positive electrode film was 7.0-7.8 mg / cm. 2 It was. Example 5b: Preparation of sulfur-carbon cathode using PAA binder (CMD, sodium polyacrylate) A mixture of ethanol, aqueous PAA-Na solution, and conductive carbon was mixed in a FlackTek SpeedMixer™ to form a slurry. Ethanol and a powder containing 80% sulfur and 20% carbon were added at intervals. The slurry was cast onto a carbon-coated aluminum foil using a doctor blade. The cathode was dried under ambient conditions for 2 hours and then placed in a vacuum oven at 60°C overnight. The final total solids loading of the resulting cathode film was 6.5-7.3 mg / cm. 2 It was. Example 6: Fabrication and testing of coin-cell batteries using cathodes formulated with supramolecular and non-supramolecular binders Coin Cell Preparation: Cutouts of the dried cathode films described in Examples 4a, 4b, 5a, and 5b were assembled into coin cells using Celgard™ separators and lithium metal anodes. Each cell contained sufficient electrolyte to provide an E / S ratio of 4 μL / mg-S. Each cell was provided with a conventional Li-FSI-based electrolyte (0.8 M LiFSI, 0.3 M LiNO3 in DOL / DME). Five cells containing each cathode composition were cycled using a Maccor battery test system according to the following protocol: the cells were cycled five times at a rate of 100 mA / g for one cycle, 200 mA / g for two cycles, and 333 mA / g for two cycles, and then the cells were equilibrated and prepared for cycle life testing. After the initial equilibration procedure, a cycle life test was conducted involving 20 loops. Each loop included one charge / discharge cycle at 100 mA / g, followed by 19 charge / discharge cycles at 333 mA / g. Cycle life testing of coin cell batteries: The cycle life of the batteries was evaluated by measuring the number of cycles completed before the measured discharge capacity dropped to 80% of the battery's initial capacity. As shown in Figure 6, the batteries using the supramolecular binder (solid bars) have a longer cycle life than the comparison battery using only NaPAA (hatched bars). This trend is consistent for both conventional carbon-sulfur cathodes (carbon melt-diffusion or CMD) and hybrid sulfur-metal sulfide cathodes (SMS).

[0105] The systems, devices, methods, and processes of the present disclosure are intended to encompass variations and adaptations developed using information from the embodiments described herein. Adaptations and / or modifications of the systems, devices, methods, and processes described herein may be performed by those skilled in the relevant art.

[0106] Throughout this specification, when articles, devices, and systems are described as having, including, or comprising particular components, or when processes and methods are described as having, including, or comprising particular steps, it is further contemplated that there are articles, devices, and systems according to certain embodiments of the disclosure that consist essentially of, or consist of, the recited components, and that there are processes and methods according to certain embodiments of the disclosure that consist essentially of, or consist of, the recited processing steps.

[0107] It should be understood that the order of steps or the order in which certain actions are performed is immaterial, provided that operability is not lost. Additionally, two or more steps or actions may be performed simultaneously. As will be understood by those skilled in the art, the terms "over," "under," "above," "below," "beneath," and "on" are relative terms and may be interchangeable with respect to different orientations of layers, elements, and substrates included in the present disclosure. For example, a first layer on a second layer, in some embodiments, refers to a first layer that is directly on and in contact with the second layer. In other embodiments, a first layer on a second layer may include another layer therebetween.

[0108] Headings are provided for the convenience of the reader and are not intended to be limiting with respect to the claimed subject matter.

[0109] Specific embodiments of the present disclosure have been described above. However, it is expressly noted that the present disclosure is not limited to these embodiments; rather, additions and modifications to those explicitly described in the present disclosure are also intended to be within the scope of the present disclosure. Furthermore, it should be understood that the features of the various embodiments described in the present disclosure are not mutually exclusive and may exist in various combinations and permutations without departing from the spirit and scope of the present disclosure, even if such combinations or permutations are not explicitly stated. Although the present disclosure has been described in detail with particular reference to specific embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the claimed invention.

Claims

1. 1. An electrode (e.g., positive electrode) composition for a (e.g., lithium-sulfur) battery, the composition comprising an electrochemically active material and a binder, the binder comprising chemically interacting Lewis acid and Lewis base sites.

2. 10. The electrode composition of claim 1, wherein the binder comprises two different species, each of which contains either the Lewis acid site or the Lewis base site.

3. 3. The electrode composition of claim 2, wherein one of the two different species is a polymer (e.g., an ionomer) and the other of the two different species is a particle (e.g., a nanoparticle).

4. The electrode composition of claim 3 , wherein the particles are silica particles, metal oxide particles, or metal fluoride particles.

5. 5. The electrode composition of claim 3 or claim 4, wherein the particles are porous (e.g., mesoporous).

6. The electrode composition of claim 2 , wherein the two different species are different polymers (e.g., two ionomers).

7. 7. The electrode composition of claim 6, wherein one of the two different species is a cationic polymer and the other of the two different species is an anionic polymer.

8. 10. An electrode composition according to any one of the preceding claims, wherein the binder in the composition forms a network of nodes where the Lewis acid sites and the Lewis base sites chemically interact.

9. 9. The electrode composition of claim 8, wherein the binder comprises two different species, one of which contains the Lewis acid sites and the other of which contains the Lewis base sites.

10. 10. The electrode composition of any one of the preceding claims, wherein a first species comprises either the Lewis acidic site or the Lewis basic site and is soluble in an aqueous solvent, and a different second species comprises the other of the Lewis acidic site and the Lewis basic site and is insoluble in an aqueous solution (e.g., the water-insoluble species is a particle (e.g., a nanoparticle)).

11. 11. The electrode composition of claim 10, wherein the first species comprises the Lewis acid site and is water-insoluble, and the second species comprises the Lewis base site and is water-soluble (e.g., the binder is introduced to the composition as a slurry comprising the water-soluble second species and the water-insoluble first species in particulate form).

12. 10. An electrode composition according to any one of the preceding claims, wherein the binder comprises a water-soluble portion and a water-insoluble portion that chemically interact with each other.

13. 10. An electrode composition according to any one of the preceding claims, wherein the binder comprises particles containing only the Lewis acid sites or only the Lewis base sites.

14. 10. An electrode composition according to any one of the preceding claims, wherein the binder comprises a linear polymer containing only the Lewis acid sites or only the Lewis base sites.

15. 10. An electrode composition according to any one of the preceding claims, wherein the binder comprises one or more polymers into whose / their polymer backbones the Lewis acidic and / or Lewis basic moieties are incorporated in the form of functional groups.

16. The electrode composition of claim 15 , wherein the binder defines (e.g., forms) a supramolecular polymer network in the composition.

17. 10. The electrode composition of claim 1, wherein the binder comprises a neutral species (e.g., comprising a boron center) that comprises the Lewis acid or Lewis base site.

18. 10. The electrode composition of any one of the preceding claims, wherein the binder comprises species that decorate the surface of the electrochemically active material.

19. 10. An electrode composition according to any one of the preceding claims, wherein particles comprise the electrochemically active material and the binder comprises species that decorate the particles.

20. The electrochemically active material may be sulfur (e.g., S ８ sulfur in the form of a cyclic eight-atom molecule), lithium sulfide (e.g., Li ２ S ２ and / or Li ２ 10. The electrode composition of any one of the preceding claims, comprising one or more members selected from the group consisting of: sulfur compounds, chalcogenides (e.g., metal sulfides), and organosulfur compounds.

21. 10. An electrode composition according to any one of the preceding claims, comprising an electronically conductive material (e.g. conductive carbon).

22. 22. The electrode composition of claim 21, wherein the binder comprises a species that decorates the surface of the electronically conductive material.

23. 23. The electrode composition of claim 21 or claim 22, wherein particles comprise the electronically conductive material and the binder comprises species that decorate the particles.

24. 24. The electrode composition according to claim 21, wherein the electronically conductive material is a conductive carbon that is a conductive carbon powder (e.g., carbon black, Super P (registered trademark), C-NERGY™ Super C65, Ensaco (registered trademark) black, Ketjenblack (registered trademark), acetylene black, synthetic graphite such as Timrex (registered trademark) SFG-6, Timrex (registered trademark) SFG-15, Timrex (registered trademark) SFG-44, Timrex (registered trademark) KS-6, Timrex (registered trademark) KS-15, Timrex (registered trademark) KS-44, natural exfoliated graphite, graphene, carbon nanotubes, fullerene, hard carbon, and / or mesocarbon microbeads).

25. 10. The electrode composition of any one of the preceding claims, wherein the binder comprises a first component selected from the group consisting of cationic polymers and a second component selected from anionic polymers.

26. 26. The electrode composition of claim 25, wherein the first component comprises a polymer containing an ammonium group or a cationic heterocyclic group, or the first component comprises ammonium, pyridinium, or imidazolium, or the first component comprises poly(diallyldimethylammonium), poly(3-vinylimidazolium).

27. 27. The electrode composition of claim 26, wherein the first component further comprises an anion selected from carboxylate, FSI, TFSI, BF4-, iodide, nitrate, or hexafluorophosphate, or wherein the first component further comprises an anion selected from FSI and TFSI.

28. 26. The electrode composition of claim 25, wherein the second component is from the group of anionic polymers comprising functional groups selected from carboxylate, sulfonate, phosphate, borate, thiosulfate, thionate, thiocarboxylate, dithiocarbamate, carbamate, thiocarbamate, xanthate, thiocarboxylate, dithiocarboxylate, carbonate, monothiocarbonate, dithiocarbonate, trithiocarbonate, hexafluorophosphate, thiophosphate, and borate.

29. 10. A lithium-sulfur battery comprising a positive electrode comprising the electrode composition of any one of the preceding claims (e.g., the electrode composition disposed as a coating on a current collector).

30. 1. A method for producing a composition (e.g., an electrode composition (e.g., as defined in any one of claims 1 to 28)), the method comprising: combining components of a binder (e.g., with an electrochemically active material) in a slurry, wherein the components include species that are soluble in the slurry and species that are insoluble in the slurry; and chemically interacting the soluble species with the insoluble species to form the binder (e.g., to bind the electrochemically active material).

31. 31. The method of claim 30, wherein the soluble species comprises Lewis base sites or Lewis acid sites and the insoluble species comprises Lewis acid sites or Lewis base sites, respectively, and wherein chemically interacting comprises interacting the Lewis acid sites with the Lewis base sites.

32. 32. The method of claim 31 , wherein the soluble species comprises the Lewis basic site and the insoluble species comprises the Lewis acid site.

33. The method of any one of claims 30 to 32, wherein the slurry is an aqueous slurry.

34. The method of any one of claims 30 to 33, wherein the insoluble species is a particle or a linear polymer.

35. 35. The method of any one of claims 30 to 34, wherein the soluble species is a polymer (e.g., a linear polymer).

36. 36. The method of any one of claims 30-35, comprising forming the insoluble species prior to the combining, wherein forming the insoluble species comprises performing metathesis (e.g., anionic metathesis) with a precursor material (e.g., resulting in a precipitated product (e.g., the insoluble species)).

37. 37. The method of claim 36, wherein the precursor material comprises one or more materials comprising one or more first anions selected from the group consisting of trifluoroacetate, trifluoromethanesulfonate, 2-trifluoromethyl-4,5-dicyanoimidazole, bis(trifluoromethane)sulfonimide ("TFSI"), and tetrafluoroborate (e.g., where the one or more anions are selected to minimize their mass fraction in the product, thus achieving a higher mass content of cationic polymeric units).

38. 38. The method of claim 36 or claim 37, wherein the metathesis is carried out in water and the insoluble species is insoluble in water.

39. 38. The method of claim 36 or claim 37, wherein the metathesis is carried out in a non-aqueous solvent and the insoluble species is insoluble in water.

40. 40. The method of any one of claims 36 to 39, wherein forming the insoluble species comprises performing a second metathesis (e.g., anionic metathesis) (e.g., on the product obtained from the first metathesis) in a non-aqueous solvent (e.g., acetonitrile).

41. 41. The method of claim 40, wherein the second metathesis is carried out with one or more materials comprising one or more second anions.

42. 42. The method of claim 41, wherein the one or more second anions are selected from the group consisting of tetrafluoroborate and bis(fluoro)sulfonamide.

43. 43. The method of claim 41 or claim 42, wherein the first one or more anions are different from the one or more second anions.

44. 44. The method of any one of claims 41 to 43, wherein the one or more second anions are lighter than the one or more first anions.

45. 45. The method of any one of claims 41 to 44, wherein the one or more first anions are TFSI and the one or more second anions are tetrafluoroborate.

46. 46. ​​The method of any one of claims 40 to 45, comprising dissolving the resulting product (e.g., precipitate) of the metathesis in the non-aqueous solvent used to carry out the second metathesis.

47. 47. The method of any one of claims 30 to 46, comprising decorating an electrochemically active material with the insoluble species prior to said combining.

48. 48. The method of claim 47, comprising forming the insoluble species, wherein forming the insoluble species comprises performing metathesis in the presence of the electrochemically active material (e.g., particles of an electrochemically active material), and wherein the decoration occurs during the metathesis.

49. 49. The method of claim 48, wherein the metathesis is performed in water and the electrochemically active material is water insoluble (e.g., a carbon-sulfur active material).

50. 48. The method of claim 47, comprising forming the insoluble species, wherein forming the insoluble species comprises performing a first metathesis and a subsequent second metathesis, wherein the subsequent second metathesis, but not the first metathesis, is performed in the presence of the electrochemically active material (e.g., particles of an electrochemically active material), and wherein the decoration occurs during the metathesis.

51. 51. The method of claim 50, wherein the electrochemically active material is soluble in a solvent used in the first metathesis and insoluble in a solvent used in the second metathesis.

52. 52. The method of claim 51 , wherein the electrochemically active material is water soluble.

53. 53. The method of any one of claims 50 to 52, wherein the electrochemically active material comprises a metal sulfide.

54. 54. A method according to any one of claims 30 to 53, comprising decorating an electronically conductive material (e.g. conductive carbon) with the insoluble species prior to said combining.

55. 55. The method of claim 54, comprising forming the insoluble species, wherein forming the insoluble species comprises performing metathesis in the presence of the electrochemically active material (e.g., particles of an electrochemically active material), and wherein the decoration occurs during the metathesis.

56. 56. The method of claim 55, wherein the metathesis is carried out in water and the electronically conductive material is water-insoluble.

57. 57. The method of any one of claims 30 to 56, wherein the chemical interaction occurs at room temperature and / or in air.

58. 58. The method of any one of claims 30 to 57, wherein the chemical interaction occurs spontaneously when the components are combined.

59. 1. A method for preparing a species for use in a binder, the method comprising performing metathesis to replace a counterion in the species such that the solubility of the species in a solvent changes from soluble to insoluble or from insoluble to soluble.

60. 60. The method of claim 59, wherein the species changes from being soluble in the solvent to being insoluble in the solvent.

61. 61. The method of claim 59 or claim 60, comprising carrying out the metathesis in the presence of a material (e.g., particles of a material) such that the species decorate the material.

62. 59. The method of any one of claims 56 to 58, comprising carrying out the metathesis in the presence of a material (e.g., particles of a material) such that the seeds decorate the surface of the material.

63. 63. The method of any one of claims 59 to 62, wherein the material is an electrochemically active material or an electronically conductive material.

64. A composite material comprising a material and a binder, the binder comprising chemically interacting Lewis acid and Lewis base moieties.

65. 65. The composition of claim 64, wherein the binder comprises particles comprising the material that holds the particles together.

66. 66. The composition of claim 64 or claim 65, wherein the composition is a film (e.g., a self-supporting film) (e.g., a coating on a substrate).

67. 6. The electrode composition according to claim 3 or claim 5, wherein the particles are metal sulfide particles or carbon particles.

68. 59. The method of any one of claims 30 to 58, wherein the soluble species comprises Lewis basic sites and the insoluble species comprises Lewis acid sites.

69. 69. The method of claim 68, wherein the insoluble species is a solid (e.g., particulate) species.

70. 29. The electrode of any one of claims 1 to 28, wherein the binder is introduced into the electrode composition from a slurry comprising the water-soluble species comprising Lewis acid sites and water-insoluble species comprising Lewis base sites.

71. 71. The electrode of claim 70, wherein the water-insoluble species is a particle.

72. 70. The method of any one of claims 30-58, 68 and 69, wherein the binder is formed upon mixing of a water-soluble species with a complementary water-insoluble species (e.g., upon mixing of a first species containing Lewis acid sites with a second species containing Lewis base sites).

73. 70. The method of any one of claims 30-58, 68 and 69, wherein the binder is formed upon full or partial drying of a slurry comprising water-soluble species and complementary water-insoluble species (e.g., a first species comprising Lewis acid sites and a second species comprising Lewis base sites).

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