Polymeric binders for silicon or silicon-graphite composite electrodes and their use in electrochemical cells

Abstract

To provide a polymer binder for a silicon or silicon-graphite composite electrode and use thereof in an electrochemical cell.SOLUTION: Polymers, polymer binders, hydrogel polymer binders, hydrogel polymer binder compositions comprising the same, electrode materials comprising the same, methods for their production and their use in electrochemical cells, such as silicon-based electrochemical cells, are described. The hydrogel binder may be formed primarily through H-bonding between the water-soluble polymer binder and polyphenols, which may serve as strong interactions or physical crosslinking points, thereby forming 3D complexes.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Related Applications This application claims priority under applicable law to U.S. Provisional Application No. 62 / 728,531, filed September 7, 2018, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] Technical Field The technical field relates generally to polymers, polymer binders, hydrogel polymer binder compositions comprising them, electrode materials comprising them, methods of making them, and their use in electrochemical cells. [Background technology]

[0003] background Silicon is Li 15 Due to its high theoretical specific capacity of approximately 4200 mAh / g upon formation of Si4, it is one of the most promising negative electrode materials for future rechargeable batteries. The capacity is approximately 10 times greater than that of conventional graphite negative electrodes (approximately 372 mAh / g) (see Liu, Y. et al., Accounts of Chemical Research 2017, 50.12, 2895-2905; and Hays, K. A. et al., Journal of Power Sources 2018, 384, 136-144). However, silicon negative electrodes experience severe volume expansion upon lithiation, reaching over 300% of their original volume and causing irreversible failure, pulverization, and / or cracking, resulting in rapid capacity fade and significant cycle life reduction.

[0004] Several approaches have been suggested to overcome the capacity and stability issues associated with using conventional Si-based negative electrodes. For example, silicon monoxide and / or its suboxides (i.e., SiO xThe use of oxygen has been identified as one of the solutions to reduce its volume expansion and enhance cyclability. However, the capacity decreases significantly with increasing oxygen content. Most solutions required the inclusion of silicon by mixing it with carbon materials and / or polymer binders. For example, Si or SiO x Blending Si with graphite or graphene to form Si-graphite or Si-graphene composite electrodes has been proposed as a solution to accommodate volumetric changes while maintaining attractive capacity (Hays, KA et al., supra; Guerfi, A., et al., Journal of Power Sources 2011, 196.13, 5667-5673; and Loveridge, MJ, et al., Scientific Reports 2016, 6, (See 37787).

[0005] Poly(vinyl difluoride) (PVdF) is one of the most commonly used binders in commercial batteries, especially for batteries containing graphite as the negative electrode. However, PVdF is unsuitable for Si-based negative electrodes (see Hays, K.A. et al., supra; Guerfi, A. et al., supra; and Yoo, M. et al., Polymer 2003, 44.15, 4197-4204). Some binders have been used to mitigate volume changes during lithiation; for example, alginate (a polysaccharide derivative of cellulose) (Kovalenko, I. et al., Science 2011, 334. 6052, 75-79), poly(acrylic acid) (PAA) (Hays, K.A. et al., supra; and Komaba, S. et al., The Journal of Physical Chemistry C 2011, 115.27, 13487-13495) and polyimide (PI) (see Guerfi, A. et al., supra) have been given partial success.

[0006] Polymers with polar groups have been found to be useful for enhancing mechanical adhesion and, as a result, preventing electrode degradation (Kierzek, K., Journal of Materials Engineering and Performance 2016, 25.6, 2326-2330; and Ryou, M. H. et al., Advanced materials 2013, 25.11, 1571-1576). For example, PAA can neutralize the Si surface to prevent side reactions. Hydroxyl groups on the Si surface can also be neutralized through covalent bond formation, for example, by esterification reactions (Zhao, H. et al., Nano Letters 2014, 14.11, 6704-6710).

[0007] Another solution is to coat the Si-based material with, for example, a self-healing polymer or hydrogel. For example, using a self-healing polymer coating, cracks and damage can be autonomously repaired. Self-healing polymer binders have been successfully applied to fabricate Si negative electrodes with low loading of active materials (Wang, C. et al., Nature Chemistry 2013, 5, 1042). The reduced loading allows for limited negative electrode volume expansion (approximately 1 mg / cm). 2 ). Stable Si-based negative electrodes have also been obtained by in situ polymerization of conductive hydrogels to form conformal coatings that bond to the Si surface. However, the loading in such materials is still very low (Wu, H. et al., Nature Communications 2013, 4, 1943). Thus, there is a need to improve the capacity and / or stability of silicon-based batteries despite the significant volume expansion upon lithiation of silicon negative electrodes. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Liu, Y.ら, Accounts of chemical research 2017, 50.12, 2895-2905

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Non-licensed literature 9

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[0009] Abstract According to one aspect, the present technology provides compounds of formula I and II: [ka] a polymer comprising monomer units derived from the polymerization of R 1 independently, in each occurrence, —OH and optionally substituted C 1-6 Alkyl-OH or -CO2C 1-6 is selected from OH-containing groups such as alkyl-OH; and R 2 and R 3 each independently at each occurrence represents a hydrogen atom and an optionally substituted C 1-6 alkyl.

[0010] In one embodiment, the polymer is a copolymer of Formula III: [ka] where R 1 , R 2 and R 3 is as defined herein; and n and m are integers selected so that the number average molecular weight is from about 2,000 g / mol to about 250,000 g / mol.

[0011] In another embodiment, a copolymer as defined herein is an alternating copolymer, a random copolymer, or a block copolymer.

[0012] According to another aspect, the present technology relates to an electrode material comprising a polymer as defined herein. In one embodiment, the electrode material further comprises an electrochemically active substance and a binder comprising the polymer.

[0013] According to another aspect, the present technology relates to an electrode material comprising a polymer as defined herein, an electrochemically active substance, optionally a binder, and optionally a polyphenol. In one embodiment, the electrode material comprises the binder, and the binder comprises a polymer as defined herein.

[0014] According to another aspect, the present technology relates to an electrode material comprising an electrochemically active substance, amylopectin, optionally a binder, and optionally a polyphenol. In one embodiment, the electrode material comprises the binder, and the binder comprises amylopectin. In another embodiment, the binder further comprises the polyphenol.

[0015] According to another aspect, the present technology relates to an electrode material comprising an electrochemically active substance and a binder, wherein the binder comprises amylopectin. In one embodiment, the binder further comprises a polyphenol.

[0016] In accordance with another aspect, the present technology relates to an electrode material comprising an electrochemically active substance and a hydrogel binder, the hydrogel binder comprising a water-soluble polymeric binder and a polyphenol.

[0017] In one embodiment, the electrochemically active material is a silicon-based electrochemically active material. For example, the silicon-based electrochemically active material may be silicon, silicon monoxide (SiO), silicon suboxide (SiO x ) and combinations thereof. For example, the silicon-based electrochemically active material is selected from the group consisting of silicon suboxide (SiO x) where x is 0 <x<2であるものである。

[0018] In another embodiment, the silicon-based electrochemically active material further comprises graphite or graphene.

[0019] In another embodiment, the polyphenol is selected from the group consisting of tannin, catechol, and lignin. For example, the polyphenol is a polyphenol polymer. For example, the polyphenol polymer is tannic acid.

[0020] In another embodiment, the water-soluble polymer binder comprises a functional group selected from the group consisting of a carboxyl group, a carbonyl group, an ether group, an amine group, an amide group, and a hydroxyl group. In one example, the water-soluble polymer binder is a homopolymer. Alternatively, the water-soluble polymer binder is a copolymer. For example, the copolymer is an alternating copolymer, a random copolymer, or a block copolymer.

[0021] In another embodiment, the water-soluble polymeric binder comprises a monomer unit of Formula V: [ka] where R 4 is independently, in each occurrence, -COH, -OH, optionally substituted -COC 1-6 Alkyl, optionally substituted C 5-6 Heterocycloalkyl, required -OC substituted accordingly 1-6 Alkyl and optionally substituted -C 1-6 Alkyl-OH or -CO2C 1-6 selected from OH-containing functional groups such as alkyl-OH; R 5 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; R 6represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; and o is an integer selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol, inclusive.

[0022] In another embodiment, the water soluble polymeric binder is selected from the group consisting of poly(vinyl alcohol) (PVOH), poly(acrylic acid) (PAA), poly(vinylpyrrolidone) (PVP), poly(2-hydroxyethyl methacrylate-co-acrylic acid), poly(vinyl alcohol-co-acrylic acid), poly(acrylic acid-co-maleic acid) (PAAMA), polyethylene oxide (PEO), poly(methyl vinyl ether-alt-maleic acid) (PVMEMA), gelatin, and polysaccharides.

[0023] According to another aspect, the present technology relates to a binder composition for use in an electrode material, the composition comprising a polyphenol and a water-soluble polymer.

[0024] In one embodiment, the polyphenol is selected from the group consisting of tannin, catechol, and lignin. For example, the polyphenol is tannic acid.

[0025] In another embodiment, the water-soluble polymer comprises a functional group selected from the group consisting of a carboxyl group, a carbonyl group, an ether group, an amine group, an amide group, and a hydroxyl group. In one example, the water-soluble polymer is a homopolymer. Alternatively, the water-soluble polymer is a copolymer. For example, the copolymer is an alternating copolymer, a random copolymer, or a block copolymer.

[0026] In another embodiment, the water-soluble polymer comprises a monomer unit of formula V: [ka] where R 4 is independently, in each occurrence, -COH, -OH, optionally substituted -COC 1-6 Alkyl, optionally substituted C 5-6 Heterocycloalkyl, optionally substituted -OC 1-6 Alkyl and optionally substituted -CO2C 1-6 alkyl-OH; R 5 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; R 6 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 a selected from Lukil; and o is an integer selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol, inclusive.

[0027] In another embodiment, the water-soluble polymer is selected from the group consisting of poly(vinyl alcohol) (PVOH), poly(acrylic acid) (PAA), poly(vinylpyrrolidone) (PVP), poly(2-hydroxyethyl methacrylate-co-acrylic acid), poly(vinyl alcohol-co-acrylic acid), poly(acrylic acid-co-maleic acid) (PAAMA), polyethylene oxide (PEO), poly(methyl vinyl ether-alt-maleic acid) (PVMEMA), gelatin, and polysaccharides.

[0028] According to another aspect, the present technology relates to an electrode material comprising a binder composition as defined herein and an electrochemically active material.

[0029] According to another aspect, the present technology relates to an electrode material as defined herein on a current collector.

[0030] In one embodiment, the electrode is a negative electrode. Alternatively, the electrode is a positive electrode.

[0031] According to a further aspect, the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode or the positive electrode is as defined herein.

[0032] According to a further aspect, the present technology relates to a battery comprising at least one electrochemical cell as defined herein. [Brief explanation of the drawings]

[0033] [Figure 1] 1 shows three charge-discharge cycles: the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for Cell 1 as described in Example 4 at a temperature of 25° C.

[0034] [Figure 2] 2 shows three charge-discharge cycles: the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for Cell 2 as described in Example 4 at a temperature of 25° C.

[0035] [Figure 3]3 shows three charge-discharge cycles: the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for Cell 3 as described in Example 4 at a temperature of 25° C.

[0036] [Figure 4] FIG. 4 shows a graph of % capacity retention versus cycle number for Cell 1 (open circle line) and Cell 2 (solid circle line) as described in Example 4.

[0037] [Figure 5] 5 shows three charge-discharge cycles: the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for Cell 4 as described in Example 4 at a temperature of 25° C.

[0038] [Figure 6] 6 shows three charge-discharge cycles, the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for Cell 5 as described in Example 4 at a temperature of 25° C.

[0039] [Figure 7] 7 shows four charge-discharge cycles for Cell 6 as described in Example 4. The first cycle was performed at 0.05 C at a temperature of 25° C. (solid line), the second cycle was performed at 0.1 C at a temperature of 25° C. (dashed line), the third cycle was performed at 0.2 C at a temperature of 45° C. (dash-dotted line), and the fourth cycle was performed at 0.2 C at a temperature of 45° C. (dotted line).

[0040] [Figure 8]8 shows four charge-discharge cycles for Cell 7 as described in Example 4. The first cycle was performed at 0.05 C at 25° C. (solid line), the second cycle was performed at 0.1 C at 25° C. (dashed line), the third cycle was performed at 0.2 C at 45° C. (dash-dotted line), and the fourth cycle was performed at 0.2 C at 45° C. (dotted line).

[0041] [Figure 9] 9 shows three charge-discharge cycles, the first at 0.05 C (solid line), the second at 0.05 C (dashed line), and the third at 0.1 C (dotted line) for Cell 8 as described in Example 4 at a temperature of 25° C.

[0042] [Figure 10] 10 shows three charge-discharge cycles for Cell 9 as described in Example 4 at a temperature of 25° C. The first cycle was performed at 0.05 C (solid line), the second cycle was performed at 0.05 C (dashed line), and the third cycle was performed at 0.1 C (dotted line).

[0043] [Figure 11] 11 shows four charge-discharge cycles for cell 10 as described in Example 4. The first cycle was performed at 0.05 C at a temperature of 25° C. (solid line), the second cycle was performed at 0.1 C at a temperature of 25° C. (dashed line), the third cycle was performed at 0.2 C at a temperature of 45° C. (dash-dotted line), and the fourth cycle was performed at 0.2 C at a temperature of 45° C. (dotted line).

[0044] [Figure 12] FIG. 12 shows a graph of % capacity retention versus cycle number for Cell 4 (open triangle line), Cell 5 (closed triangle line), Cell 8 (open circle line), and Cell 9 (closed circle line) as described in Example 4.

[0045] [Figure 13]FIG. 13 shows a graph of capacity (mAh / g) versus cycle number for Cell 4 (open triangle line), Cell 5 (closed triangle line), Cell 8 (open circle line), and Cell 9 (closed circle line) as described in Example 4.

[0046] [Figure 14] FIG. 14 shows a graph of capacity retention (%) versus cycle number for Cell 7 (black triangle line), Cell 4 (white triangle line), Cell 1 (white square line), and Cell 2 (black square line) as described in Example 4.

[0047] [Figure 15] FIG. 15 shows a graph of capacity (mAh / g) versus cycle number for Cell 1 (open square line), Cell 2 (closed square line), Cell 4 (open triangle line), and Cell 7 (closed triangle line) as described in Example 4.

[0048] [Figure 16] FIG. 16 shows a graph of % capacity retention versus cycle number for cell 10 (solid circle line) and cell 6 (solid triangle line) as described in Example 4.

[0049] [Figure 17] 17 shows three charge-discharge cycles for cell 11, where the first cycle was performed at 0.05 C (solid line), the second cycle was performed at 0.05 C (dashed line), and the third cycle was performed at 0.1 C (dotted line) at a temperature of 25° C.

[0050] [Figure 18] 18 shows three charge-discharge cycles for cell 12 at a temperature of 25° C. The first cycle was performed at 0.05 C (solid line), the second cycle was performed at 0.05 C (dashed line), and the third cycle was performed at 0.1 C (dotted line).

[0051] [Figure 19]19 shows three charge-discharge cycles: the first cycle at 0.05 C (solid line), the second cycle at 0.05 C (dashed line), and the third cycle at 0.1 C (dotted line) for cell 13 at a temperature of 25° C.

[0052] [Figure 20] 20 shows three charge-discharge cycles for cell 14 at a temperature of 25° C. The first cycle was performed at 0.05 C (solid line), the second cycle was performed at 0.05 C (dashed line), and the third cycle was performed at 0.1 C (dotted line).

[0053] [Figure 21] Figure 21 shows three charge-discharge cycles for cell 15, where the first cycle was at 0.05 C (solid line), the second cycle was at 0.05 C (dashed line), and the third cycle was at 0.1 C (dotted line) at a temperature of 25°C.

[0054] [Figure 22] 22 shows three charge-discharge cycles for cell 16, where the first cycle was at 0.05 C (solid line), the second cycle was at 0.05 C (dashed line), and the third cycle was at 0.1 C (dotted line) at a temperature of 25° C. DETAILED DESCRIPTION OF THE INVENTION

[0055] Detailed Description The following detailed description and examples are illustrative and should not be construed to further limit the scope of the invention.

[0056] All technical and scientific terms and expressions used herein have the same definitions as those commonly understood by those skilled in the art when they relate to the technology of the present invention. Nevertheless, definitions of some terms and expressions used herein are provided below for the purpose of clarity.

[0057] When the term "approximately" or its equivalent term "about" is used herein, it means approximately or in the region of, and around. When the term "approximately" or "about" is used in connection with a numerical value, it modifies that numerical value; for example, by a ±10% variance of the nominal figure. The term may also account for the probability of rounding of numbers or random error in experimental measurements, for example, due to instrumental limitations.

[0058] For greater clarity, the phrase "monomeric units derived from" and equivalent phrases, as used herein, refer to polymer repeat units that result from a polymerizable monomer after polymerization thereof.

[0059] The chemical structures depicted herein are drawn according to conventional standards, and where an atom (e.g., a carbon atom as written) appears to contain an incomplete valence, it is assumed that the valence is filled by one or more hydrogen atoms, even if not necessarily explicitly written.

[0060] As used herein, the term "alkyl" refers to a saturated hydrocarbon having 1 to 6 carbon atoms, including straight or branched alkyl groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, tertbutyl, secbutyl, isobutyl, and the like. When an alkyl group is positioned between two functional groups, the term alkyl also encompasses alkylene groups such as methylene, ethylene, propylene, and the like. The term "C1-C n "Alkyl" refers to alkyl groups having from 1 to the indicated "n" number of carbon atoms.

[0061] The term "heterocycloalkyl" and equivalent expressions refer to a group containing a saturated or partially unsaturated (non-aromatic) carbocyclic ring in a monocyclic system having 5 to 6 ring members, in which one or more ring members is a substituted or unsubstituted heteroatom (e.g., N, O, S, P) or a group containing such a heteroatom (e.g., NH, NR x (where R x is alkyl, acyl, aryl, heteroaryl or cycloalkyl), PO, SO, SO, etc. Heterocycloalkyl groups may be attached to C or to a heteroatom (e.g., via a nitrogen atom) where this is possible.

[0062] According to a first aspect, the present technology provides compounds of formula I and II: [ka] a polymer comprising monomer units derived from the polymerization of R 1 independently, at each occurrence, represents —OH and OH-containing groups (e.g., optionally substituted C 1-6 Alkyl-OH or -CO2C 1-6 alkyl-OH); and R 2 and R 3 each independently at each occurrence represents a hydrogen atom and an optionally substituted C 1-6 alkyl.

[0063] For example, the polymer may be a copolymer of Formula III: [ka] where R 1 , R 2 and R 3is as defined herein; and n and m are number average molecular weights of from about 2 000 g / mol to about 250 000 g / mol, e.g., from about 10 000 g / mol to about 200 000 g / mol, or about 25 000 g / mol to about 200 000 g / mol, or even about 25 000 g / mol to about 150 000 g / mol, or about 50 000 g / mol to about 150 000 g / mol, or about 75 000 g / mol to about 125 000 g / mol (boundaries is an integer selected to be the number average molecular weight of

[0064] In some embodiments, the copolymer of Formula III can be, for example, an alternating copolymer, a random copolymer, or a block copolymer. For example, the copolymer is a random copolymer or a block copolymer.

[0065] In some embodiments, the monomer unit of Formula I is selected from vinyl alcohol, hydroxyethyl methacrylate (HEMA), and derivatives thereof.

[0066] In some embodiments, the monomer unit of formula II is selected from acrylic acid (AA), methacrylic acid (MA), and / or derivatives thereof.

[0067] According to a variant of the invention, the polymer is a copolymer comprising monomer units derived from vinyl alcohol and from AA. According to another variant of the invention, the copolymer comprises monomer units derived from HEMA and from AA.

[0068] For example, the polymer may have the formula III(a) or III(b): [ka] where m and n are as defined herein.

[0069] Polymerization of the monomers can be achieved by any known procedure and initiation method, for example, by radical polymerization.

[0070] The radical initiator can be any suitable polymerization initiator, such as an azo compound (e.g., azobisisobutyronitrile (AIBN)). Polymerization can be further initiated by photolysis, thermal treatment, and any other suitable means. For example, the initiator is AIBN.

[0071] When the copolymer is a block copolymer, its synthesis can be achieved by reversible addition-fragmentation chain transfer polymerization (or RAFT).

[0072] According to another aspect, the present technology relates to an electrode material comprising a polymer as defined herein. In some embodiments, the electrode material comprises an electrochemically active substance and, optionally, a binder. In some embodiments, the electrode material further comprises a polyphenol. For example, the binder comprises a polymer as defined herein and / or a polyphenol. When the binder is said to comprise the polymer, it is understood that this also includes the possibility that the polymer serves as the binder.

[0073] According to another aspect, the present technology relates to an electrode material comprising an electrochemically active substance and amylopectin. In some embodiments, the electrode material optionally further comprises a binder. In some embodiments, the electrode material further comprises a polyphenol. For example, the binder includes amylopectin and / or polyphenols.

[0074] In accordance with another aspect, the present technology relates to a binder composition comprising a polyphenol and a water-soluble polymer.

[0075] According to another aspect, the technology of the present invention relates to an electrode material comprising an electrochemically active substance and a hydrogel binder, wherein the hydrogel binder comprises a water-soluble polymer binder and polyphenol.

[0076] In some embodiments, the electrochemically active substance is a silicon-based electrochemically active substance. For example, the silicon-based electrochemically active substance may include silicon, or silicon monoxide (SiO), or silicon oxide, or silicon suboxide (SiO x ), or a combination thereof. For example, the silicon-based electrochemically active substance comprises SiO x , where x is 0 < x < 2, or 0.1 < x < 1.9, or 0.1 < x < 1.8, or 0.1 < x < 1.7, or 0.1 < x < 1.6, or 0.1 < x < 1.5, or 0.1 < x < 1.4, or 0.1 < x < 1.3, or 0.1 < x < 1.2, or 0.1 < x < 1.1, or 0.1 < x < 1.0 (including the boundaries). For example, x is 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8. The higher the concentration of oxygen atoms in SiO x , the electrochemically active substance may also reduce its volume expansion during lithiation, but may cause some capacity loss.

[0077] In some embodiments, the electrochemically active substance further comprises a carbon material (e.g., carbon, graphite and graphene). For example, the graphite is natural or artificial graphite, such as artificial graphite used as a negative electrode material (e.g., SCMG TM ). For example, the electrochemically active substance is a silicon-carbon composite, or a silicon-graphite composite or a silicon-graphene composite. In one variation of the purpose, the electrochemically active substance is SiO x graphite composite. In some embodiments, the SiO x graphite composite is SiO xand up to about 100% by weight, or up to about 95% by weight, or up to about 90% by weight, or up to about 75% by weight, about 50% by weight, or between about 5% by weight and about 100% by weight, or between about 5% by weight and about 95% by weight, or between about 5% by weight and about 90% by weight, or between about 5% by weight and about 90% by weight, or between about 5% by weight and about 85% by weight, or between about 5% by weight and about 80% by weight, or between about 5% by weight and about 75% by weight, or between about 5% by weight and about 70% by weight, or about 5 % to about 65% by weight, or between about 5% to about 60% by weight, or between about 5% to about 55% by weight, or between about 5% to about 50% by weight, or between about 5% to about 45% by weight, or between about 5% to about 40% by weight, or between about 5% to about 35% by weight, or between about 5% to about 30% by weight, or between about 5% to about 25% by weight, or between about 5% to about 20% by weight, or between about 5% to about 15% by weight, or between about 5% to about 10% by weight (inclusive) x The same concentrations can also be applied while replacing graphite with another carbon material.

[0078] In some embodiments, the electrochemically active material may further comprise a coating material. For example, the electrochemically active material may comprise a carbon coating. Alternatively, the coating material may also comprise at least one of a polymer as described herein, amylopectin, and a water-soluble polymer as defined herein, and further comprise a polyphenol. Alternatively, the coating material may comprise a hydrogel binder as defined herein.

[0079] In some embodiments, the polyphenol can be a gelling agent for forming a hydrogel. The polyphenol can be a macromolecule or polymer containing a sugar or sugar-like moiety linked to multiple polyphenol groups (e.g., dihydroxyphenyl, trihydroxyphenyl, and their derivatives). For example, the polyphenol can gel the polymer or macromolecule at multiple binding sites through hydrogen bonding, effectively conjugating the polymer chain into a three-dimensional (3D) network.

[0080] The hydrogel binder as described herein is formed primarily through H-bonding between the water-soluble polymer binder and the polyphenols, which act as strong interaction or physical crosslinking points, thereby forming a 3D complex.

[0081] Non-limiting examples of polyphenols include tannin, lignin, catechol, and tannic acid (TA). For example, the polyphenol is a polyphenol polymer. In one variant of interest, the polyphenol polymer is a tannin, such as TA. TA is a natural polyphenol equivalent to 10 gallic acid units surrounding a monosaccharide (glucose) (see Formula IV). For example, the 25 phenolic hydroxyl and 10 ester groups of TA provide multiple binding sites for hydrogen bonding with, for example, various water-soluble polymer binder chains having hydroxyl groups to form a TA-based hydrogel binder. [ka]

[0082] In one embodiment, the water-soluble polymer binder may contain carboxyl, carbonyl, ether, amine, amide, or hydroxyl groups to form hydrogen bonds with polyphenols. Non-limiting examples of water-soluble polymer binders include poly(vinyl alcohol) (PVOH), poly(acrylic acid) (PAA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), poly(vinyl alcohol-co-acrylic acid), poly(methyl vinyl ether-alt-maleic acid) (PVMEMA ... Examples of suitable water-soluble polymer binders include poly(acrylic acid-co-maleic acid) (PAAMA), poly(2-hydroxyethyl methacrylate-co-acrylic acid), polysaccharides, amylopectin, alginate, gelatin, and derivatives thereof. In another embodiment, the water-soluble polymer contains, for example, a labile hydrogen atom on an oxygen or nitrogen atom (e.g., an OH or COH group). For example, the water-soluble polymer binder is PVOH, amylopectin, or PAA.

[0083] For example, the water-soluble polymeric binder may be a polymer of Formula V: [ka] where R 4 is independently, in each occurrence, -COH, -OH, optionally substituted -COC 1-6 Alkyl, optionally substituted C 5-6 Heterocycloalkyl, optionally substituted -OC 1-6 Alkyl and optionally substituted -C 1-6 Alkyl-OH or -CO2C 1-6 selected from OH-containing functional groups such as alkyl-OH; R 5 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; R 6 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6alkyl; and o is an integer selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 250 000 g / mol, or from about 27 000 g / mol to about 250 000 g / mol, inclusive.

[0084] For example, the water-soluble polymeric binder may be a polymer of formula V(a), V(b), or V(c): [ka] Includes.

[0085] In some embodiments, the water-soluble polymer binder is a homopolymer. Alternatively, the water-soluble polymer binder is a copolymer. For example, when the polymer is a copolymer, the copolymer can be, for example, an alternating copolymer, a random copolymer, or a block copolymer. In one variation, the copolymer is a random copolymer. In another variation, the copolymer is a block copolymer.

[0086] Alternatively, the water-soluble polymeric binder has the formula VI(a), VI(b) or VI(c): Polymers of: [ka] where p and q are integers independently selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 250 000 g / mol, or from about 27 000 g / mol to about 250 000 g / mol, inclusive.

[0087] Alternatively, the water-soluble polymeric binder comprises a polysaccharide. For example, the water-soluble polymeric binder may comprise a polymer of Formula VII: [ka] where r is an integer selected to provide a number average molecular weight of from about 2,000 g / mol to about 400,000 g / mol, or from about 2,000 g / mol to about 250,000 g / mol, or from about 25,000 g / mol to about 250,000 g / mol, or from about 27,000 g / mol to about 250,000 g / mol, inclusive. In some examples, the polysaccharide may also further include derivatives thereof, such as carboxymethyl-substituted polysaccharides (e.g., carboxymethylcellulose).

[0088] In some embodiments, the water-soluble polymeric binder has a molecular weight of about 2,000 g / mol to about 400,000 g / mol, or about 2,000 g / mol to about 250,000 g / mol, or about 25,000 g / mol to about 250,000 g / mol, or about 27,000 g / mol to about 300,000 g / mol. It has a number average molecular weight of from 000 g / mol to about 250 000 g / mol (inclusive).

[0089] In some embodiments, the hydrogel binder comprises up to about 10% by weight of polyphenols. For example, the hydrogel binder comprises between about 1% and about 10% by weight, or between about 1% and about 9% by weight, or between about 1% and about 8% by weight, or between about 1% and about 7% by weight, or between about 1% and about 6% by weight, or between 1% and about 5% by weight, or between about 1% and about 4% by weight, or between about 1% and about 3% by weight, or between about 1% and about 2% by weight of polyphenols, based on the total weight of the hydrogel binder (total weight including water that may be removed after electrode formation). For example, the hydrogel binder may comprise between about 1% and about 10% by weight, or between about 1% and about 9% by weight, or between about 1% and about 8% by weight, or between about 1% and about 7% by weight, or between about 1% and about 6% by weight, or between 1% and about 5% by weight, or between about 1% and about 4% by weight, or between about 1% and about 3% by weight, or between about 1% and about 2% by weight of polyphenols. The total weight of the binder contains about 2% by weight of polyphenols.

[0090] In some embodiments, the hydrogel binder comprises between about 1% and about 30% by weight, or between about 5% and about 25% by weight, or between about 10% and about 25% by weight, or between about 10% and about 20% by weight, or between about 15% and about 20% by weight, or between about 15% and about 17% by weight of polyphenol, based on the total weight of polyphenol and polymer. For example, the hydrogel binder comprises a polymer to polyphenol weight ratio of about 10:2.

[0091] In some embodiments, the hydrogel binder comprises up to about 20% by weight of a water-soluble polymer binder. For example, the hydrogel binder comprises between about 1% and about 15% by weight, or between about 5% and about 15% by weight, or between about 7% and about 15% by weight, or between about 8% and about 15% by weight, or between about 9% and about 15% by weight, or between about 9% and about 13% by weight, or between about 9% and about 12% by weight, or between about 9% and about 11% by weight, inclusive, of the total weight of the hydrogel binder (total weight including water that may be removed after electrode formation). For example, the hydrogel binder comprises about 10% by weight of a water-soluble polymer binder.

[0092] In some embodiments, the hydrogel binder comprises water. For example, the hydrogel binder comprises at least about 60% water by weight, prior to the optional drying step. For example, the hydrogel binder comprises between about 60% and about 98% water by weight, or between about 60% and about 98% water by weight, or between about 64% and about 98% water by weight, or between about 70% and about 98% water by weight, or between about 75% and about 98% water by weight, or between about 80% and about 98% water by weight, or between about 80% and about 95% water by weight, or between about 82% and about 95% water by weight, or between about 83% and about 94% water by weight, or between about 84% and about 93% water by weight, or between about 85% and about 92% water by weight, or between about 86% and about 91% water by weight, or between about 87% and about 90% water by weight, inclusive. For example, the hydrogel binder contains about 88% water by weight, prior to the optional drying step.

[0093] In some embodiments, the hydrogel is a biobased hydrogel. For example, the hydrogel binder may exhibit, for example, improved mechanical performance, improved flexibility, improved elasticity, improved stretchability, improved self-healing properties, improved adhesive properties, and / or improved shape memory properties. For example, the hydrogel binder may exhibit improved tensile strength and / or elongation and / or modulus. Furthermore, the hydrogel binder may be readily commercialized because large quantities of the hydrogel binder can be easily prepared given that no complex synthetic procedures are involved. In such biobased hydrogels, the polymer is, for example, amylopectin or gelatin. In one variant of interest, the hydrogel comprises amylopectin.

[0094] In some embodiments, the electrode materials as described herein may further comprise a conductive material. The electrode materials may also optionally include additional components or additives, such as salts, inorganic particles, glass or ceramic particles, and the like.

[0095] Non-limiting examples of conductive materials include carbon black (e.g., Ketjen TM Black), acetylene black (e.g., Shawinigan Black and Denka TM Black), graphite, graphene, carbon fiber, carbon nanofiber (e.g., vapor grown carbon fiber (VGCF)), carbon nanotubes (CNT), and combinations thereof. For example, the conductive material can be Ketjen TM It is a combination of black and VGCF.

[0096] According to another aspect, the present technology relates to an electrode comprising an electrode material as defined herein on a current collector. For example, the electrode is a negative electrode or a positive electrode. In one variation of the object, the electrode is a negative electrode.

[0097] According to a further aspect, the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode or the positive electrode is as defined herein, e.g., the negative electrode is as defined herein.

[0098] In some embodiments, the electrolyte can be a liquid electrolyte comprising a salt in a solvent, or a gel electrolyte comprising a salt in a solvent that may further comprise a solvating polymer, or a solid polymer electrolyte comprising a salt in a solvating polymer. In one variation of the subject, the salt is a lithium salt.

[0099] Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPF), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (LiBF), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNO), lithium chloride (LiCl), lithium brominated fluoride (LiBr), lithium fluoride (LiF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium trifluoromethanesulfonate (LiSOCF) (LiTf), and fluoroalkyl lithium phosphates. Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate [B(CO2)] (LBBB), and combinations thereof. According to one variant of interest, the lithium salt is lithium hexafluorophosphate (LiPF6).

[0100] For example, the solvent is a non-aqueous solvent. Non-limiting examples of non-aqueous solvents include cyclic carbonates (e.g., ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC)); acyclic carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and dipropyl carbonate (DPC)); lactones (e.g., γ-butyrolactone (γ-BL) and γ-valerolactone (γ-VL)); chain ethers (chain ethers) ethers) such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), ethoxymethoxyethane (EME), trimethoxymethane, and ethyl monoglyme; cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane and dioxolane derivatives; and other solvents such as dimethyl sulfoxide, formamide, acetamide, dimethylformamide, acetonitrile, propylnitrile, nitromethane, phosphoric acid triesters, sulfolane, methylsulfolane, propylene carbonate derivatives, and mixtures thereof. According to one variant of interest, the solvent is an alkyl carbonate (acyclic or cyclic) or a mixture of two or more carbonates (e.g., EC / EMC / DEC (4:3:3)).

[0101] In some embodiments, the electrolyte may also include at least one electrolyte additive, for example, to form a stable solid electrolyte interface (SEI) and / or to improve the cyclability of the silicon-based electrochemically active material. The electrolyte additive is fluoroethylene carbonate (FEC).

[0102] In some embodiments, an electrochemical cell as defined herein can have improved electrochemical performance (eg, improved cyclability).

[0103] According to a further aspect, the present technology relates to a battery comprising at least one electrochemical cell as defined herein. For example, the battery is selected from a lithium battery, a lithium-sulfur battery, a lithium-ion battery, a sodium battery, and a magnesium battery. In one variation of the object, the battery is a lithium-ion battery. [Example]

[0104] The following non-limiting examples are illustrative embodiments and should not be construed to further limit the scope of the present invention. These examples are better understood when viewed in conjunction with the accompanying drawings.

[0105] Example 1: Polymer synthesis a) Random copolymerization of AA and HEMA Random copolymers were prepared according to the copolymerization process as illustrated in Scheme 1: [ka] where n and m are as defined herein.

[0106] According to the process of Scheme 1, HEMA was first filtered through basic aluminum oxide (alumina, Al2O3), and AA was distilled under reduced pressure. To carry out this copolymerization, 7.2 g of HEMA, 4.0 g of AA, and 100 mL of N,N-dimethylformamide (DMF) were introduced into a round-bottom flask. Nitrogen was then bubbled through the solution for 30 minutes to remove oxygen. Azobisisobutyronitrile (AIBN, 48 mg) was then added, and the solution was heated to 70 °C under nitrogen for at least 12 hours. The polymer was then purified by precipitation in 10 volumes of toluene or diethyl ether, isolated, and dried under vacuum for 12 hours.

[0107] b) Block copolymerization of AA and HEMA The block copolymers were prepared by a two-step RAFT copolymerization process as illustrated in Scheme 2: [ka] where n and m are as defined herein.

[0108] Formation of PAA blocks The first step involves the polymerization of AA by RAFT polymerization to form a first block containing AA monomer units. In this first step, 10.0 g of AA, 38.5 mg of S,S-dibenzyltrithiocarbonate (RAFT CTA), and 100 mL of dioxane were introduced into a round-bottom flask. The solution was then stirred at room temperature and purged with nitrogen for 30 minutes to remove oxygen. 77.0 mg of AIBN was added, and the solution was heated to a temperature of 85° C. under nitrogen for at least 3 hours.

[0109] The polymer was then purified by precipitation with 10 volumes of toluene and dried under vacuum for 12 hours at 80° C. The typical production yield obtained in the first step of this procedure was about 7.6 g.

[0110] Poly(HEMA) block formation and copolymerization The second step involves the formation of a second block containing a HEMA monomer unit. In this second step, 6.0 g of the previous polymer (PAA-RAFT), 13.0 g of HEMA, and 250 ml of DMF were added to a round-bottom flask. The solution was stirred at room temperature and nitrogen was bubbled through for 30 minutes to remove oxygen. 75 mg of AIBN was then added to the reaction mixture, and the solution was heated to 65° C. under nitrogen for at least 12 hours. The polymer was then purified by precipitation with 10 volumes of diethyl ether and hexane (3:1) and dried under vacuum for 12 hours.

[0111] Example 2: Water-soluble polymer-TA hydrogel binder preparation a) PVOH-TA hydrogel binder preparation This example illustrates the preparation of a hydrogel binder of TA and PVOH. An aqueous binder solution was prepared using 10% by weight Millipore Sigma TM PVOH (MW ∼27 000 g / mol) and 2 wt % TA were prepared by dissolving them in water at a temperature of 60° C. The mixture was then cooled to room temperature, thereby effectively creating strong H-bonds between the TA and PVOH and weaker H-bonds between the PVOH chains, forming a PVOH-TA hydrogel.

[0112] b) Random poly(2-hydroxyethyl methacrylate-co-acrylic acid)-TA hydrogel binder preparation This example illustrates the preparation of a hydrogel binder of TA and the copolymer of Example 1(a). An aqueous binder solution was prepared by dissolving 12 wt. % of the copolymer of Example 1(a) and 4 wt. % of TA in an aqueous ethanol mixture (20 wt. %) at a temperature of 60° C. (The ethanol was added before the addition of TA.) The mixture was then cooled to room temperature, thereby effectively creating strong H-bonds between the TA and the copolymer of Example 1(a) and weaker H-bonds between the copolymer chains of Example 1(a), forming a hydrogel.

[0113] c) Block poly(2-hydroxyethyl methacrylate-co-acrylic acid)-TA hydrogel binder preparation This example illustrates the preparation of a hydrogel binder of TA and the copolymer of Example 1(b). An aqueous binder solution was prepared by dissolving 12 wt. % of the copolymer of Example 1(b) and 4 wt. % of TA in an aqueous ethanol mixture (20 wt. %) at a temperature of 60° C. (The ethanol was added before the addition of TA.) The mixture was cooled to room temperature, thereby effectively creating strong H-bonds between the TA and the copolymer of Example 1(b) and weaker H-bonds between the copolymer chains of Example 1(b), forming a hydrogel.

[0114] d) PAA-TA hydrogel binder preparation This example illustrates the preparation of a hydrogel binder of TA and PAA. An aqueous binder solution was prepared by dissolving 10% by weight of Acros Organics TA and PAA in water at a temperature of 60° C. TM The PAA-TA hydrogel was prepared by dissolving 100% PAA (25 wt % aqueous solution; MW ∼240 000 g / mol) and 5 wt % TA. The mixture was then cooled to room temperature, thereby effectively creating strong H-bonds between TA and PAA and weaker H-bonds between the PAA chains, forming a PAA-TA hydrogel.

[0115] Hydrogel binder compositions containing 10 wt% PAA and 2 wt% TA, and hydrogel binder compositions containing 10 wt% PAA and 1 wt% TA were also prepared using the method described in Example 1(d).

[0116] e) Preparation of PVP-TA hydrogel binder This example illustrates the preparation of a hydrogel of TA and PVP. An aqueous binder solution was prepared using 10% by weight Millipore Sigma TM PVP (MW ∼29 000 g / mol) and 1 wt % TA were prepared by dissolving them in water at a temperature of 60° C. The mixture was then cooled to room temperature, which effectively created strong H-bonds between the TA and PVP and weaker H-bonds between the PVP chains, forming a PVP-TA hydrogel.

[0117] f) Amylopectin-TA hydrogel binder preparation This example illustrates the preparation of a hydrogel binder of TA and amylopectin. An aqueous binder solution was prepared by dissolving 7 wt. % amylopectin and 1 wt. % TA in water at a temperature of 60° C. The mixture was then cooled to room temperature, thereby effectively creating strong H-bonds between the TA and amylopectin and weaker H-bonds between the amylopectin chains, forming an amylopectin-TA hydrogel.

[0118] Example 3: SiO with hydrogel binder x -Graphite electrodes The hydrogel binder prepared according to the procedure in Example 2 was applied to different cells (each with SiO x - graphite electrode and lithium metal counter electrode). x -The graphite used in the graphite electrodes is SCMG from Showa Denko. TM Different SiO x Electrodes with different carbon to graphite ratios were prepared (about 5 wt%, about 10 wt%, about 25 wt%, and about 50 wt%).

[0119] SiO x - The graphite electrode material was heated at 2000 rpm for 30 seconds to form a solid (i.e., SiO x , SCMG TM and conductive material). Then, PVOH-TA aqueous binder solution (from Example 2(a)) was added to the different solid mixtures. The different mixtures were then mixed three times (each time at 2,000 rpm for 1 minute). Water was then added three times to the different mixtures to obtain different slurries with appropriate viscosities. After each water addition, the slurry was mixed at 2,000 rpm for 1 minute. The resulting slurries were then each cast onto a copper current collector using a doctor blade method and dried at a temperature of 80°C for 15 minutes. Table 1. 50 wt% ratio (SiO x :Gr is 50:50) electrode material weight concentration [Table 1] *PVOH-TA aqueous binder solution from Example 2(a) Table 2. 25 wt% ratio (SiO x :Gr is 25:75) electrode material weight concentration [Table 2] *PVOH-TA aqueous binder solution from Example 2(a) Table 3. 10wt% ratio (SiOx :Gr is 10:90) electrode material weight concentration [Table 3] *PVOH-TA aqueous binder solution from Example 2(a) Table 4. 5wt% ratio (SiO x :Gr is 5:95) electrode material weight concentration [Table 4] *PVOH-TA aqueous binder solution from Example 2(a)

[0120] All electrodes have a density of approximately 8.0 to 10.0 mg / cm 2 and about 1.2 to about 1.4 g / cm 3 The electrodes had a volumetric mass density in the range of 0.1 to 1.0 μm.

[0121] For comparison purposes, a reference electrode containing 5 wt% PVdF (MW approximately 9400 g / mol) as a binder in N-methyl-2-pyrrolidone (NMP) was prepared by simply replacing the PVOH-TA aqueous binder solution with PVdF binder at the same weight ratios detailed in Tables 1-4.

[0122] Example 4: Electrochemical properties Tables 5-7 show the weight concentrations of electrochemically active materials E1-E3, the weight concentrations of hydrogel binders B1-B6, and the electrode compositions for each of cells 1-15, respectively, which will be referenced when discussing the electrochemical properties measured in this example. Table 5. Weight concentrations of electrochemically active substances [Table 5] Table 6. Hydrogel binder weight concentrations [Table 6-1] [Table 6-2] Table 7. Electrode material composition for cells 1 to 15 [Table 7]

[0123] All cells were fabricated using standard stainless steel button cell castings, polyethylene-polyethylene terephthalate-polyethylene (PE / PET / PE) based separators impregnated with a 1 M LiPF solution in EC / EMC / DEC (4:3:3) and 5% FEC as the liquid electrolyte, and SiO on copper current collectors. x -Assembled with a graphite electrode and a lithium metal counter electrode.

[0124] a) Electrode material weight concentration for 50% by weight ratio The effect of the choice of water-soluble polymer binder and the presence of polyphenols in the hydrogel binder is shown in Figures 1-4, 17 and 18. For a 50 wt% Si ratio, the predicted capacity is 1036 mAh g -1 It was.

[0125] Figure 1 shows three charge-discharge cycles for Cell 1 (comparison cell). The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C (dotted line), respectively, at a temperature of 25°C. Figure 1 shows a significantly lower capacity than predicted and a significant capacity loss with cycling.

[0126] Figure 2 shows three charge-discharge cycles for Cell 2. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25 °C. Although not as pronounced as in Figure 1, a small capacity loss can also be observed with cycling. Furthermore, the capacity is slightly lower than predicted. These results effectively demonstrate that a hydrogel binder containing amylopectin and TA may be a suitable binder choice for silicon-graphite composite electrodes.

[0127] Figure 3 shows three charge-discharge cycles for Cell 3. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25°C. Although not as pronounced as in Figure 1, a small capacity loss can also be observed with cycling. Furthermore, the capacity is close to the predicted capacity, effectively demonstrating that a hydrogel binder containing PVOH and TA may be a suitable binder choice for silicon-graphite composite electrodes.

[0128] Figure 17 shows three charge-discharge cycles for Cell 11. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C (dotted line), respectively, at a temperature of 25 °C. Cell 11 contains a hydrogel binder as prepared in Example 2(b) containing random poly(2-hydroxyethyl methacrylate-co-acrylic acid) copolymer as prepared in Example 1(a) and TA. Similar to Figures 1-3, capacity loss can also be observed with cycling in Figure 17. However, compared to Cell 1, Cell 11 has a capacity significantly closer to its predicted capacity. These results effectively demonstrate that a hydrogel binder containing random poly(2-hydroxyethyl methacrylate-co-acrylic acid) copolymer and TA may be a suitable binder choice for silicon-graphite composite electrodes.

[0129] FIG. 18 shows three charge-discharge cycles for Cell 12. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25° C. Cell 12 contains a hydrogel binder as prepared in Example 2(c) comprising block poly(2-hydroxyethyl methacrylate-co-acrylic acid) copolymer as prepared in Example 1(b) and TA. Compared to Cell 1, Cell 12 also has a capacity significantly closer to its predicted capacity, effectively demonstrating that a hydrogel binder comprising block poly(2-hydroxyethyl methacrylate-co-acrylic acid) copolymer and TA may also be a suitable binder choice for silicon-graphite composite electrodes.

[0130] Figure 4 is a graph of capacity retention (%) versus cycle number for Cell 1 (open circle line) and Cell 2 (filled circle line). Figure 4 shows a significant loss in capacity retention when cycling with a PVdF binder (Cell 1). A loss in capacity retention can also be observed when cycling with a binder containing amylopectin and TA. However, the loss is less significant in Cell 2 than in Cell 1, effectively demonstrating that amylopectin and TA may be good binder candidates for silicon-graphite composite electrodes.

[0131] b) Electrode material weight concentration for 25% by weight ratio The effect of TA and water-soluble polymer is further shown in Figures 5-8, 19 and 20. For a 25 wt% Si ratio, the predicted capacity is 704 mAh g -1 It was.

[0132] Figure 5 shows three charge-discharge cycles for Cell 4, prepared for comparison purposes without TA. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25°C. Figure 5 shows the predicted The cells exhibit significantly lower capacities than those obtained with the cells and significant capacity loss with cycling.

[0133] The effect of the presence of TA in the binder is shown in Figure 6, which shows three charge-discharge cycles for Cell 5. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25°C. Figure 6 shows a higher capacity than that of Cell 4.

[0134] The effect of TA in the binder is also shown in Figure 7, which shows four charge-discharge cycles for Cell 6. The first cycle (solid line) was performed at 0.05 C at a temperature of 25°C, the second cycle (dashed line) was performed at 0.1 C at a temperature of 25°C, the third cycle (dash-dotted line) was performed at 0.2 C at a temperature of 45°C, and the fourth cycle (dotted line) was performed at 0.2 C at a temperature of 45°C. Figure 7 shows that after the first cycle, capacity loss becomes less pronounced.

[0135] The effect of TA is further illustrated in FIG. 8, which shows four charge-discharge cycles for cell 7. The first cycle (solid line) was performed at 0.05 C at a temperature of 25° C., the second cycle (dashed line) was performed at 0.1 C at a temperature of 25° C., the third cycle (dash-dotted line) was performed at 0.2 C at a temperature of 45° C., and the fourth cycle (dotted line) was performed at 0.2 C at a temperature of 45° C. FIG. 8 shows that capacity loss becomes less pronounced after the first cycle. The effect of temperature is also illustrated.

[0136] Figure 19 shows three charge-discharge cycles for cell 13. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C (dotted line), respectively, at a temperature of 25°C.

[0137] 20 shows three charge-discharge cycles for cell 14. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25° C.

[0138] c) Electrode material weight concentration for a 10% by weight ratio The effect of TA and water-soluble polymer is further shown in Figures 9-11, 21 and 22. For a 10 wt% Si ratio, the predicted capacity is 505 mAh g -1 It was.

[0139] Figure 9 shows three charge-discharge cycles for Cell 8, prepared for comparison purposes without TA. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C, respectively, at a temperature of 25°C. Figure 9 shows significant capacity loss with cycling.

[0140] Figure 10 shows three charge-discharge cycles for Cell 9. The first (solid line), second (dashed line), and third (dotted line) cycles were performed at 0.05 C, 0.05 C, and 0.1 C at a temperature of 25°C. Figure 10 shows no significant capacity loss with cycling. This effectively demonstrates that a binder containing PVOH and TA may be a suitable binder candidate for silicon-graphite composite electrodes.

[0141] Figure 11 shows four charge-discharge cycles for cell 10. The first cycle was performed at 0.05 C (solid line) at a temperature of 25°C, the second cycle was performed at 0.1 C (dashed line) at a temperature of 25°C, the third cycle was performed at 0.2 C (dash-dotted line) at a temperature of 45°C, and the fourth cycle was performed at 0.2 C (dotted line) at a temperature of 45°C. Figure 11 shows that capacity loss becomes less significant after the first cycle. The effect of temperature is also shown.

[0142] Figure 21 shows three charge-discharge cycles for cell 15. The first (solid line), second (dashed line), and third (dotted line) cycles were at 0.05 C, 0.05 C, and 0.1 C at a temperature of 25°C. Compared to cell 13 (Figure 19) and cell 11 (Figure 17), cell 15 has lower capacity. However, cell 15 also has lower capacity as it cycles.

[0143] Figure 22 shows three charge-discharge cycles. The first (solid line), second (dashed line), and third (dotted line) cycles were at 0.05 C, 0.05 C, and 0.1 C at a temperature of 25°C for cell 16. Compared to cells 14 (Figure 20) and 12 (Figure 18), cell 16 has lower capacity. However, cell 16 has improved capacity retention with cycling compared to the other two (i.e., cells 14 and 12).

[0144] d) PVOH capacity retention (%) versus cycle number The effect of TA and electrochemically active material composition on capacity retention is shown in Figure 12, which shows a graph of capacity retention (%) versus cycle number for Cell 4 (open triangle line), Cell 5 (closed triangle line), Cell 8 (open circle line), and Cell 9 (closed circle line). Figure 12 effectively demonstrates that the presence of TA positively impacts capacity retention as cycling occurs. Figure 12 also demonstrates that a lower wt% of Si in the electrochemically active material results in improved capacity retention.

[0145] e) PVOH capacity (mAh / g) versus cycle number The effect of TA and electrochemically active material composition on capacity is shown in Figure 13. Figure 13 shows the capacity (mAh g) versus cycle number for Cell 4 (open triangle line), Cell 5 (closed triangle line), Cell 8 (open circle line), and Cell 9 (closed circle line). -1 ) is shown. Figure 13 effectively demonstrates that the presence of TA in the binder positively impacts capacity.

[0146] f) Amylopectin-TA capacity retention (%) versus number of cycles Figure 14 shows the % capacity retention as a function of cycle number for Cell 7 (black triangle line), Cell 4 (white triangle line), Cell 1 (white square line), and Cell 2 (black square line). As expected, the % capacity retention is dependent on the amount of SiO2 in the electrochemically active material composition. xThe capacitance decreases more sharply as the content (wt%) of TA increases. The presence of TA in the hydrogel binder has a positive effect on the capacitance.

[0147] g) Amylopectin-TA capacity (mAh / g) versus cycle number The measured capacity (mAh / g) as a function of cycle number for Cell 1 (open square line), Cell 2 (closed square line), Cell 4 (open triangle line), and Cell 7 (closed triangle line) is shown in Figure 15. These results show that the presence of TA in the binder positively impacts the capacity. The capacity is a function of the amount of SiO in the composition of the electrochemically active materials. x (wt%) increases, which is expected.

[0148] h) PAA-TA capacity retention (%) versus cycle number Figure 16 shows the % capacity retention versus cycle number for Cell 10 (black circle line) and Cell 6 (black triangle line). As expected, the % capacity retention is dependent on the amount of SiO in the electrochemically active material composition. x The decrease becomes more pronounced as the (wt%) increases.

[0149] Many modifications can be made to any of the embodiments described above without departing from the scope of the present invention. Any references, patents or scientific literature documents mentioned in this application are incorporated herein by reference in their entirety for all purposes. can be. The present invention provides, for example, the following items. (Item 1) Compounds of Formula I and II: [ka] 1. A polymer comprising monomer units derived from the polymerization of R 1 independently, in each occurrence, —OH and optionally substituted C 1-6 Alkyl-OH or -CO2C 1-6is selected from OH-containing groups such as alkyl-OH; and R 2 and R 3 each independently at each occurrence represents a hydrogen atom and an optionally substituted C 1-6 selected from alkyl, polymer. (Item 2) The polymer is a copolymer of Formula III: [ka] where R 1 , R 2 and R 3 is as defined in item 1; and n and m are integers selected so that the number average molecular weight is from about 2,000 g / mol to about 250,000 g / mol; Item 1. The polymer according to item 1. (Item 3) 3. The polymer according to item 2, wherein the number average molecular weight is from about 10 000 g / mol to about 200 000 g / mol, or from about 25 000 g / mol to about 200 000 g / mol, or from about 25 000 g / mol to about 150 000 g / mol, or from about 50 000 g / mol to about 150 000 g / mol, or from about 75 000 g / mol to about 125 000 g / mol, inclusive. (Item 4) 4. The polymer according to any one of items 1 to 3, wherein the polymer is an alternating copolymer, a random copolymer, or a block copolymer. (Item 5) 5. The polymer according to claim 4, wherein the polymer is a random copolymer. (Item 6) 5. The polymer according to item 4, wherein the polymer is a block copolymer. (Item 7) 10. An electrode material comprising a polymer as defined in any one of items 1 to 6, an electrochemically active substance, optionally a binder, and optionally a polyphenol. (Item 8) 8. The electrode material according to item 7, wherein the binder comprises the polymer. (Item 9) Item 9. The electrode material according to item 7 or 8, wherein the binder comprises the polyphenol. (Item 10) An electrode material comprising an electrochemically active substance, amylopectin, optionally a binder and optionally a polyphenol. (Item 11) Item 11. The electrode material according to item 10, wherein the binder comprises amylopectin. (Item 12) Item 12. The electrode material according to item 10 or 11, wherein the binder comprises the polyphenol. (Item 13) 1. An electrode material comprising an electrochemically active substance and a hydrogel binder, wherein the hydrogel binder comprises a water-soluble polymeric binder and a polyphenol. (Item 14) Item 14. The electrode material of item 13, wherein the water-soluble polymer binder comprises a functional group selected from the group consisting of a carboxyl group, a carbonyl group, an ether group, an amine group, an amide group, and a hydroxyl group. (Item 15) 15. The electrode material according to item 13 or 14, wherein the water-soluble polymeric binder is a homopolymer. (Item 16) 16. The electrode material according to any one of items 13 to 15, wherein the water-soluble polymer binder is a copolymer. (Item 17) 17. The electrode material according to item 16, wherein the copolymer is an alternating copolymer, a random copolymer, or a block copolymer. (Item 18) Item 18. The electrode material according to item 17, wherein the copolymer is a random copolymer. (Item 19) Item 18. The electrode material according to item 17, wherein the copolymer is a block copolymer. (Item 20) The water-soluble polymeric binder has a molecular weight of about 2,000 g / mol to about 400,000 g / mol, or about 2,000 g / mol to about 250,000 g / mol, or about 25,000 g / mol. 20. The electrode material according to any one of items 13 to 19, having a number average molecular weight of from about 27 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol (inclusive). (Item 21) The water-soluble polymeric binder comprises a monomer unit of formula V: [ka] where R 4 is independently, in each occurrence, -COH, -OH, optionally substituted -COC 1-6 Alkyl, optionally substituted C 5-6 Heterocycloalkyl, optionally substituted -OC 1-6 Alkyl and optionally substituted -C 1-6 Alkyl-OH or -CO2C 1-6 selected from OH-containing functional groups such as alkyl-OH; R 5 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; R 6 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; and o is an integer selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol, inclusive; 21. The electrode material according to any one of items 13 to 20. (Item 22) 22. The electrode material according to any one of items 13 to 21, wherein the water-soluble polymer binder is selected from the group consisting of poly(vinyl alcohol) (PVOH), poly(acrylic acid) (PAA), poly(vinylpyrrolidone) (PVP), poly(2-hydroxyethyl methacrylate-co-acrylic acid), poly(vinyl alcohol-co-acrylic acid) and poly(acrylic acid-co-maleic acid) (PAAMA). (Item 23) 23. The electrode material according to item 22, wherein the water-soluble polymer binder is poly(vinyl alcohol) (PVOH). (Item 24) 23. The electrode material of item 22, wherein the water-soluble polymer binder is poly(acrylic acid) (PAA). (Item 25) 22. The electrode material according to any one of items 13 to 21, wherein the water-soluble polymer binder is selected from the group consisting of polyethylene oxide (PEO), poly(methyl vinyl ether-alt-maleic acid) (PVMEMA), gelatin and polysaccharides. (Item 26) 26. The electrode material according to item 25, wherein the polysaccharide is selected from the group consisting of amylopectin and alginate. (Item 27) 26. The electrode material according to item 25, wherein the water-soluble polymer binder is amylopectin. (Item 28) 28. The electrode material according to any one of items 13 to 27, wherein the hydrogel binder contains 1 wt % to 5 wt % of the polyphenol. (Item 29) Item 29. The electrode material according to item 28, wherein the hydrogel binder contains 1% by weight to 3% by weight of the polyphenol. (Item 30) 30. The electrode material according to any one of items 7 to 29, wherein the electrochemically active material is a silicon-based electrochemically active material. (Item 31) The silicon-based electrochemically active material may be silicon, silicon monoxide (SiO), silicon suboxide (SiO xThe electrode material according to item 30, selected from the group consisting of and combinations thereof. (Item 32) The silicon-based electrochemically active material is silicon suboxide (SiO x ) and The electrode material according to item 30 or 31, where x is 0 < x < 2. (Item 33) The electrode material according to any one of items 30 to 32, where the silicon-based electrochemically active material further contains graphite or graphene. (Item 34) The electrode material according to item 33, where the graphite is artificial graphite (e.g., SCMG). (Item 35) The electrode material according to item 33 or 34, where the silicon to graphite ratio is up to 50:50 wt%. (Item 36) The electrode material according to item 33 or 34, where the silicon to graphite ratio is 5:95 wt% to 95:5 wt%. (Item 37) The electrode material according to any one of items 7 to 36, where the electrode material further contains a conductive material. (Item 38) The electrode material according to item 37, where the conductive material is selected from the group consisting of carbon black, acetylene black, graphite, graphene, carbon fiber, carbon nanofiber, carbon nanotube, and combinations thereof. (Item 39) The electrode material according to item 37 or 38, where the conductive material is a combination of carbon fiber and carbon black. (Item 40) The electrode material according to item 38 or 39, where the carbon fiber is vapor-grown carbon fiber (VGCF). (Item 41) The electrode material according to any one of items 38 to 40, where the carbon black is Ketjen TM black. (Item 42) 42. The electrode material according to any one of items 7 to 41, wherein the polyphenol is selected from the group consisting of tannin, catechol, and lignin. (Item 43) 43. The electrode material according to any one of items 7 to 42, wherein the polyphenol is a polyphenol polymer. (Item 44) Item 44. The electrode material according to item 43, wherein the polyphenol polymer is tannic acid. (Item 45) 1. A binder composition for use in an electrode material, the composition comprising a polyphenol and a water-soluble polymer. (Item 46) Item 46. The binder composition of item 45, wherein the polyphenol is selected from the group consisting of tannin, catechol, and lignin. (Item 47) 47. The binder composition of claim 46, wherein the polyphenol is tannic acid. (Item 48) 48. The binder composition according to any one of items 45 to 47, wherein the water-soluble polymer comprises a functional group selected from the group consisting of a carboxyl group, a carbonyl group, an ether group, an amine group, an amide group, and a hydroxyl group. (Item 49) 49. The binder composition according to any one of items 45 to 48, wherein the water-soluble polymer is a homopolymer. (Item 50) 49. The binder composition according to any one of items 45 to 48, wherein the water-soluble polymer is a copolymer. (Item 51) 51. The binder composition of claim 50, wherein the copolymer is an alternating copolymer, a random copolymer, or a block copolymer. (Item 52) 52. The binder composition of claim 51, wherein the copolymer is a random copolymer. (Item 53) 52. The binder composition of claim 51, wherein the copolymer is a block copolymer. (Item 54) The water-soluble polymer comprises a monomer unit of formula V: [ka] where R 4 is independently, in each occurrence, -COH, -OH, optionally substituted -COC 1-6 Alkyl, optionally substituted C 5-6 Heterocycloalkyl, optionally substituted -OC 1-6 Alkyl and optionally substituted -CO2C 1-6 alkyl-OH; R 5 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; R 6 represents, independently at each occurrence, a hydrogen atom and an optionally substituted C 1-6 alkyl; and o is an integer selected such that the number average molecular weight is from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol, inclusive; 54. The binder composition according to any one of items 45 to 53. (Item 55) 55. The binder composition of claim 54, wherein the water-soluble polymer is selected from the group consisting of poly(vinyl alcohol) (PVOH), poly(acrylic acid) (PAA), poly(vinylpyrrolidone) (PVP), poly(2-hydroxyethyl methacrylate-co-acrylic acid), poly(vinyl alcohol-co-acrylic acid), and poly(acrylic acid-co-maleic acid) (PAAMA). (Item 56) 54. The binder composition of any one of items 45 to 53, wherein the water-soluble polymer is selected from the group consisting of polyethylene oxide (PEO), poly(methyl vinyl ether-alt-maleic acid) (PVMEMA), gelatin and polysaccharides. (Item 57) 57. The binder composition of claim 56, wherein the polysaccharide is selected from the group consisting of amylopectin and alginate. (Item 58) 58. The binder composition according to any one of items 45 to 57, wherein the binder is a hydrogel binder. (Item 59) 59. The binder composition according to any one of items 45 to 58, wherein the binder composition comprises 1 wt % to 5 wt % of the polyphenol. (Item 60) Item 60. The binder composition according to item 59, wherein the binder composition comprises 1% to 3% by weight of the polyphenol. (Item 61) 61. The binder composition according to any one of items 45 to 60, wherein the water-soluble polymer has a number average molecular weight of from about 2 000 g / mol to about 400 000 g / mol, or from about 2 000 g / mol to about 250 000 g / mol, or from about 25 000 g / mol to about 240 000 g / mol, or from about 27 000 g / mol to about 240 000 g / mol (inclusive). (Item 62) 62. An electrode material comprising the binder composition according to any one of items 45 to 61 and an electrochemically active substance. (Item 63) 10. An electrode comprising an electrode material as defined in any one of items 7 to 44 and 62 on a current collector. (Item 64) Item 64. The electrode according to item 63, wherein the electrode is a negative electrode. (Item 65) Item 64. The electrode according to item 63, wherein the electrode is a positive electrode. (Item 66) 66. An electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein at least one of the negative electrode or the positive electrode is as defined in any one of items 63 to 65. (Item 67) 65. An electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the negative electrode is as defined in item 64. (Item 68) 68. The electrochemical cell of either item 66 or item 67, wherein the electrolyte comprises a solvent and a lithium salt. (Item 69) A battery comprising at least one electrochemical cell as defined in any one of items 66 to 68. (Item 70) 70. The battery of claim 69, wherein the battery is a lithium ion battery.

Claims

[Claim 1] The invention described in the specification.

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