Polymers comprising imidazole derivatives and their use in electrochemical cells

Abstract

This invention discloses polymers containing monomer units derived from vinylimidazole derivatives and their uses in electrode materials and / or electrolyte compositions, as well as methods for their preparation. Electrode materials, electrodes, and electrochemical cells comprising said polymers are also described, along with their uses.

Description

[0001] This application is a divisional application of Chinese patent application 201880044781.0, which was filed on July 6, 2018, and is entitled "Polymers comprising imidazole derivatives and their use in electrochemical batteries".

[0002] Related applications

[0003] This application claims priority to U.S. Provisional Application No. 62 / 529,146, filed July 6, 2017, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] The technical field of this invention generally relates to polymers containing monomer units derived from vinylimidazole derivatives, methods for their preparation, and their use in electrochemical cells, such as in composite electrodes and / or in polymer electrolytes. Background Technology

[0005] In the field of rechargeable batteries, polymer binders are commonly used to facilitate adhesion between active material particles and the mechanical adhesion of active materials to current collectors. Conventional polymer binders included in composite electrodes are not electrochemically active and are chemically inert within the range of potentials used. However, they make a significant contribution to the quality and stability of the battery (see Yamamoto, H et al., Lithium-Ion Batteries: Science and Technologies, Springer New York, 2009, 163-179).

[0006] The most commonly used polymer in conventional batteries is polyvinylidene fluoride (PVDF) dissolved in organic solvents such as N-methyl-2-pyrrolidone (NMP). NMP is known to be toxic, have adverse environmental impacts, and possess a very high boiling temperature (202 °C) (Guerfi, A. et al., Journal of Power Sources, 163.2 (2007): 1047-1052; Lux, SF et al., Journal of Electrochemical Society, 157.3 (2010): A320-A325). While PVDF dissolved in NMP is an effective electrochemically inert polymer binder, it has significant drawbacks for industrial applications, such as high production costs and the need for substantial energy for electrode coating after solvent evaporation (Lux, SF et al., ibid.). Furthermore, upon contact with the battery electrolyte, PVDF induces the formation of lithium fluoride, which accelerates the chemical degradation of the binder (see Guerfi, A. et al., ibid.), thereby increasing the battery degradation rate and reducing its lifespan.

[0007] The combined use of carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) is another common example of polymeric coatings used in the field of rechargeable batteries. In this aqueous polymeric binder, SBR contributes to the adhesion between the coating and the current collector, while CMC helps with thickening and dispersion, as well as adhesion between active material particles (Guerfi, A. et al., ibid.). CMC / SBR binders can be used in combination with active materials such as LiFePO4 and LTO (Chou, SL et al., Physical Chemistry Chemical Physics, 16.38 (2014): 20347-20359), but are known to be ineffective with materials such as LCO (Lee, JT et al., Journal of Power Sources 173.2 (2007): 985-989). Similarly, like PVDF / NMP, CMC / SBR binders are electrochemically inactive and do not contribute positively to battery efficiency.

[0008] Polyacrylonitrile (PAN), polyacrylic acid (PAA), and polyethylene (PVA) have been used as polymer binders for composite electrodes (Cai, ZP et al., Journal of Power Sources, 189.1 (2009): 547-551; Gong, L. et al., Electrochemistry Communications, 29 (2013): 45-47; Park, HK et al., Electrochemistry Communications, 13.10 (2011): 1051-1053). However, these polymers typically lack flexibility (high glass transition temperatures), which poses a major obstacle to their application. In fact, these polymer binders are known to form cracks during repeated electrode cycles, leading to a loss of integrity in the composite electrode (Tran, B. et al., Electrochimica Acta 88 (2013): 536-542).

[0009] Generally speaking, apart from some literature using conductive adhesives (see Chen, WM et al., Electrochimica Acta, 56.6 (2011): 2689-2695; and Javier, AE et al., Angewandte Chemie International Edition, 50.42 (2011): 9848-9851), most polymers used as adhesives are reported to be electrochemically inert.

[0010] Conductive polymers incorporating 2-vinyl-4,5-dicyanimidazole monomers are known for their use in photovoltaic cell applications (Densmore, CG, et al., Macromolecules 37.16 (2004): 5900-5910; Shin, RYC, et al., Journal of Organic Chemistry 74.9 (2009): 3293-3298). However, these studies do not describe the use of imidazole derivative polymers as polymer binders in applications such as rechargeable lithium batteries.

[0011] Therefore, there is a need for alternative polymers that do not have one or more of the disadvantages of the polymers mentioned above. For example, polymeric binders offer reduced production and / or usage costs, or introduce monomers that can promote the diffusion of ions within the composite electrode and / or electrolyte in an electrochemical cell. Summary of the Invention

[0012] According to one aspect, the present invention relates to polymers containing monomer units derived from formulas I and II:

[0013] in, R 1 and R 2 Each is independently selected from H, CN, F and optionally fluorinated C. 1-6 alkyl; R 3 Selected from hydrogen atoms and optionally substituted C atoms 1-6 alkyl; R 4 R 6 and R 7 Each is independently selected from hydrogen atoms and optionally substituted C atoms. 1-6 Alkyl; and R 5 Selected from -CO2H, with optional substitution of -CO2C 1-6 Alkyl, -C(O)NH2, optionally substituted -OC 1-6 Alkyl, optionally substituted C6 aryl, optionally substituted C 5-6 Heteroaryl, -CN, -SO3H, -SO2NH2, and optionally substituted -SO3C 1-6 Alkyl; or R 5 With R 7 Together with their adjacent carbon atoms, they form 5- or 6-membered heterocycles; Or a salt of the polymer.

[0014] In one embodiment, a polymer containing monomer units derived from formula I is provided:

[0015] Formula I

[0016] in, R 1 and R 2 Each is independently selected from H, CN, F and optionally fluorinated C. 1-6 Alkyl; and R 3 Selected from hydrogen atoms and optionally substituted C atoms 1-6 alkyl; Or a salt of the polymer.

[0017] In another embodiment, a polymer is provided for use in elements of an electrochemical cell, in electrode materials, in electrolyte compositions, and / or in separators. The polymer is a homopolymer containing monomer units derived from formula I, or a copolymer containing monomer units derived from formulas I and II.

[0018] In another embodiment, an electrode material is provided comprising the polymer and an electrochemically active material. The polymer is a homopolymer of monomer units derived from Formula I, or a copolymer of monomer units derived from Formulas I and II.

[0019] In another embodiment, an electrolyte is provided comprising a homopolymer containing monomer units derived from formula I, or a copolymer containing monomer units derived from formulas I and II.

[0020] In another embodiment, an electrolyte is provided comprising a separator and an electrolyte composition, wherein the separator comprises a homopolymer containing monomer units derived from formula I, or a copolymer containing monomer units derived from formulas I and II.

[0021] In another embodiment, an electrochemical cell is provided comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode, the positive electrode, and the electrolyte comprises a homopolymer containing monomer units derived from Formula I, or a copolymer containing monomer units derived from Formulas I and II.

[0022] In another embodiment, an electrochemical battery is provided, comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode and the positive electrode comprises an electrode material comprising a homopolymer containing monomer units derived from formula I, or a copolymer containing monomer units derived from formulas I and II, and comprises an electrochemically active material.

[0023] In another embodiment, an electrochemical cell is provided, comprising a negative electrode, a positive electrode, and an electrolyte, wherein the electrolyte comprises a homopolymer containing monomer units derived from Formula I, or a copolymer containing monomer units derived from Formulas I and II.

[0024] Other features and advantages of this technology can be better understood by reading the following description and figures. Attached Figure Description

[0025] Figure 1 The electrochemical impedance spectroscopy (EIS) spectra recorded using LFP / Li cells are shown. The square lines were recorded using an LFP / Li cell containing cathode material C3 (i.e., containing P(AA-copoly-2-vinyl-4,5-dicyanimidazolium)), and the diamond lines were recorded using a reference LFP / Li cell containing cathode material C1 and using PVdF binder.

[0026] Figure 2Electrochemical impedance spectroscopy (EIS) spectra recorded using LTO / Li half-cells are shown. Discontinuous lines were recorded using an LTO / Li half-cell containing anolyte A3 (i.e., containing P(AA-copoly-2-vinyl-4,5-dicyanimidazolium)), while complete lines were recorded using a reference LTO / Li half-cell containing anolyte A4 and a CMC / SBR binder.

[0027] Figure 3 The electrochemical impedance spectroscopy (EIS) of LFP / LTO cells recorded at 50% charge is shown. The square lines represent the reference cell (cell 1), and the star lines represent the cell containing P (AA-copoly-2-vinyl-4,5-dicyanimidazole) (cell 3).

[0028] Figure 4 The electrochemical impedance spectroscopy (EIS) of LFP / LTO cells recorded at -30°C and 50% charge is shown. The triangle line represents the reference cell (cell 1), and the circle line represents the cell containing P(AA-copoly-2-vinyl-4,5-dicyanimidazolium) (cell 3).

[0029] Figure 5 The graphs show the charge (a) and discharge (b) load characteristics of the LFP / Li cells. Capacity retention after charge-discharge cycles was recorded at 25°C and evaluated at different charge and discharge rates (1C, 2C, and 4C). Results for a reference LFP / Li cell containing cathode material C3 and a reference LFP / Li cell containing cathode material C1 are shown.

[0030] Figure 6 The graphs show the charge (a) and discharge (b) load characteristics of the LFP / LTO batteries. Capacity retention was recorded at 25°C and evaluated at different charge and discharge rates (1C, 2C, 4C, and 10C). Results for reference battery 4 (see Table 3), battery 5 (see Table 3), and battery 6 (see Table 3) are shown.

[0031] Figure 7 The graphs show the charge (a) and discharge (b) load characteristics of the LFP / LTO batteries. Capacity retention was recorded at 25°C and evaluated at different charge and discharge rates (1C, 2C, 4C, and 10C). Reference battery 1 (see Table 3) and battery 3 are shown. (See Table 3) and the results of heating battery 3 at 45°C.

[0032] Figure 8 The graphs show the charge (a) and discharge (b) load characteristics of the LFP / LTO batteries. Capacity retention was recorded at -15°C and evaluated at different charge and discharge rates (1C, 2C, and 4C). Reference battery 1 (see Table 3) and battery 3 are shown. (See Table 3) and the results of heating battery 3 at 45°C.

[0033] Figure 9 The graphs show the charge (a) and discharge (b) load characteristics of the LFP / LTO batteries. Capacity retention was recorded at 25°C and evaluated at different charge and discharge rates (1C, 2C, and 4C). Results for reference battery 1 (see Table 3) and battery 7 (see Table 3) are shown.

[0034] Figure 10 The Fourier transform infrared (FTIR) spectrum of the copolymer of 2-vinyl-4,5-dicyanimidazole and acrylic acid is shown. This analysis was performed at 25 °C.

[0035] Figure 11 The FTIR spectrum of the copolymer of 2-vinyl-4,5-dicyanimidazolium and acrylic acid is shown. This analysis was performed after the polymer was heated at 45°C (see Example 5(d)). Detailed Implementation

[0036] The following detailed description and examples are illustrative and should not be construed as further limiting the scope of the invention.

[0037] All technical and scientific terms and expressions used herein have the same meaning as commonly understood by those skilled in the art. Definitions of some of the terms and expressions used are also provided below.

[0038] For clarity, the phrase "monomer unit derived from..." and its equivalents herein refer to a polymer repeating unit, which is obtained after polymerization of a polymerizable monomer. For example, a monomer unit derived from vinyl is equivalent to a polymeric form of ethylene.

[0039] The chemical structures described herein are drawn according to conventional standards. Furthermore, if an atom, such as a carbon atom, appears to have an incomplete valence, it is assumed that this valence is satisfied by one or more hydrogen atoms, even if it is not explicitly shown in the structural formula.

[0040] The term "alkyl" as used herein refers to a saturated hydrocarbon group having 1-16 carbon atoms, including straight-chain or branched alkyl groups. Examples of alkyl groups include, but are not limited to: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, tert-butyl, sec-butyl, isobutyl, etc. When the alkyl group is located between two functional groups, the term alkylene also includes alkylene compounds, such as methylene, ethylene, propylene, etc. The term "C1-C" n "alkyl" means an alkyl group having 1 to "n" carbon atoms as indicated.

[0041] As used herein, the term "alkoxy" refers to an alkyl group in which an oxygen atom is attached. Representative alkoxy groups include those having 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, tert-butoxy, and so on. Examples of alkoxy groups include methoxy, ethoxy, isopropoxy, propoxy, butoxy, pentoxy, glycidyloxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, chloromethoxy, dichloromethoxy, trichloromethoxy, and so on. The term alkoxy includes both unsubstituted and substituted alkoxy groups.

[0042] The term "cycloalkyl" and its equivalents refer to a group comprising a saturated or partially unsaturated (non-aromatic) carbocyclic ring in a monocyclic or polycyclic system, including spirocyclic (sharing an atom) or fused (sharing at least one bond) carbocyclic systems having 3-15 ring members. Examples of cycloalkyl groups include, but are not limited to: cyclopropyl, cyclobutyl, cyclopentyl, cyclopenten-1-yl, cyclopenten-2-yl, cyclopenten-3-yl, cyclohexyl, cyclohexen-1-yl, cyclohexen-2-yl, cyclohexen-3-yl, cycloheptyl, bicyclo[4,3,0]nonyl, norbornyl, etc. The term cycloalkyl includes both unsubstituted and substituted cycloalkyl groups. n "Cycloalkyl" refers to a cycloalkyl group having 3 to "n" carbon atoms in its ring structure.

[0043] The term "heterocyclic alkyl" and its equivalents refer to groups comprising saturated or partially unsaturated (non-aromatic) carbocyclic rings in monocyclic or polycyclic systems, including spirocyclic (sharing an atom) or fused (sharing at least one bond) carbocyclic systems having 3-15 ring members, wherein one or more (up to 6) of the ring members are substituted or unsubstituted heteroatoms (e.g., N, O, S, P) or groups containing such heteroatoms (e.g., NH, NR). x (R xHeterocyclic alkyl groups are alkyl, acyl, aryl, heteroaryl, or cycloalkyl groups (e.g., PO2, SO, SO2, etc.). They can be attached to a carbon atom or, if possible, to a heteroatom (e.g., via a nitrogen atom). Examples of heterocyclic alkyl groups include, but are not limited to: pyrrolidinyl, tetrahydrofuranyl, tetrahydrodithienyl, tetrahydropyranyl, tetrahydrothiaranyl, piperidinyl, morpholinyl, thiomorpholinyl, thiazepinyl, piperazine, azaheptanyl, oxacyclobutane, thioheptanyl, high-piperidinyl, oxacycloheptyl, thioheptanyl, oxazepinyl, diazonyl, thiazepinyl ), 1,2,3,6-tetrahydropyridinyl, 2-pyrrolinyl, 3-pyrrolinyl, 2H-pyranyl, 4H-pyranyl, dioxane, 1,3-dioxolane, pyrazolinyl, dithiane, dithiopentane, dihydropyranyl, dihydrothiophene, dihydrofuranyl, pyrazolyl, imidazolidinyl, imidazolinyl, 3-azabicyclo[3,1,0]hexyl, 3-azabicyclo[4,1,0]heptyl, quinazinyl, sugars, etc. The term heterocyclic alkyl includes unsubstituted heterocyclic alkyl and substituted heterocyclic alkyl.

[0044] The term "aryl" indicates the presence of 4n+2 aryl groups in a conjugated monocyclic or polycyclic system (fused or unfused). (pi) An aromatic group with electrons, where n is an integer from 1 to 3, and the system has 6 to 14 ring atoms. Polycyclic cyclic systems include at least one aromatic ring. Aryl groups can be directly linked or linked via C1-C3 alkyl groups (also called arylalkyl or aralkyl groups). Examples of aryl groups include, but are not limited to: phenyl, benzyl, phenethyl, 1-phenylethyl, tolyl, naphthyl, biphenyl, terphenyl, indene, benzocyclooctenyl, benzocycloheptenyl, augenyl, acenaphthel, fluorenyl, phenanthryl, anthracene, etc. The term aryl includes both unsubstituted and substituted aryl groups. The term "C6-C" is used in conjunction with the meaning of the cyclic group. n "Aryl" indicates an aryl group having 6 to "n" carbon atoms in its ring structure.

[0045] The term "heteroaryl" refers to the presence of 4n+2 aryl groups in a conjugated monocyclic or polycyclic system (fused or unfused). (pi) An aromatic group with electrons, where n is an integer from 1 to 3, and the system has 5 to 15 ring atoms and includes 1 to 6 substituted or unsubstituted heteroatoms (e.g., N, O, S) or groups containing such heteroatoms (e.g., NH, NR). x (R xIt can be alkyl, acyl, aryl, heteroaryl, or cycloalkyl (SO, etc.). Polycyclic systems include at least one heteroaryl ring. Heteroaryl groups can be directly linked or linked via C1-C3 alkyl groups (also called heteroarylalkyl or heteroarylalkyl). Heteroaryl groups can be linked to carbon atoms or, if possible, to heteroatoms (e.g., via nitrogen atoms).

[0046] The term "substituted" when used in conjunction with any of the foregoing terms refers to a group that is substituted at one or more positions by a suitable substituent. Examples of substituents include, but are not limited to: cyano, halogen (e.g., F, Cl, Br), hydroxyl, primary, secondary, or tertiary amines, amides, nitro, diazo, trifluoromethyl, lower alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, lower alkoxy, aryloxy, benzyloxy, benzyl, carboxylic acid esters, alkoxycarbonyl, sulfonyl, sulfonate esters, sulfonamides, silanes, siloxanes, thiocarboxylic acid esters, phosphonates, hypophosphonates, oxy groups, etc. Any of the foregoing substituents may be further substituted, for example, when the group contains an alkyl, alkoxy, aryl, or other group.

[0047] This technology relates to polymers containing monomer units derived from vinylimidazole derivatives. These polymers are used, for example, in electrochemical cells as binders in electrode materials or as part of electrolyte compositions.

[0048] This technology also proposes polymers that can be used as polymer binders in composite electrodes to improve their ionic conductivity. These polymers incorporate structural portions with an affinity for ions, particularly alkali metal or alkaline earth metal ions, such as lithium ions. Using such polymer binders can reduce electrode resistance, for example at low temperatures, and / or increase battery capacity. For example, introducing vinylimidazolium derivative monomers, such as 2-vinyl-4,5-dicyanimidazolium, into the polymer can significantly reduce electrode resistance during electrochemical reactions, thereby improving battery capacity retention. The solubility of the polymers of the present invention, particularly their salt forms, can also reduce the need for the use of toxic solvents.

[0049] The use of imidazole derivative polymers, or copolymers of acrylic acid or its derivatives with imidazole derivatives (e.g., vinyl dicyanimidazole), in electrode material binders is also suggested herein, for example as a co-binder for a compatible polymer such as polyacrylic acid. Such polymers or copolymers may also be part of an electrolyte composition, such as a solid or gel polymer electrolyte.

[0050] According to the first aspect, the polymer contains monomer units derived from a vinylimidazolium derivative of formula I:

[0051] Formula I

[0052] in, R 1 and R 2 Each is independently selected from H, CN, F and optional fluorinated C. 1-6 Alkyl; and R 3 Selected from hydrogen atoms and optionally substituted C atoms 1-6 alkyl; Or their salts.

[0053] In equation I, R 1 and R 2 Each can be independently selected from CN and optionally fluorinated C. 1-6 Alkyl group. In one example, R 1 and R 2 At least one of them is CN, or both are CN. In Equation I, R 3 It can be a hydrogen atom, a methyl group, or a trifluoromethyl group. For example, R 3 It is a hydrogen atom.

[0054] According to one example, the polymer comprises 10-90 mol%, or 10-60 mol%, or 15-40 mol% of monomer units derived from a vinylimidazolium derivative of formula I, including an upper limit and a lower limit for each.

[0055] When the polymer is a copolymer, the copolymer may also contain monomer units derived from formula II:

[0056] Formula II

[0057] in, R 4 R 6 and R 7 Each is independently selected from hydrogen atoms and optionally substituted C atoms. 1-6 Alkyl; and R 5 Selected from -CO2H, with optional substitution of -CO2C 1-6 Alkyl, -C(O)NH2, optionally substituted -OC 1-6 Alkyl, optionally substituted C6 aryl, optionally substituted C 5-6 Heteroaryl, -CN, -SO3H, -SO2NH2, and optionally substituted -SO3C 1-6 Alkyl; or R 5 With R 7 Together with their adjacent carbon atoms, they form 5- or 6-membered heterocycles; Or its salt.

[0058] In one instance, R4 R 6 and R 7 At least one of them is H. In another example, R 4 R 6 and R 7 The two in are H, or each R 4 R 6 and R 7 It is H. In one instance, R 4 It is H. In another example, R 4 C is an optional substitute 1-6 Alkyl groups, such as methyl groups. In other examples, R... 5 It is -CO2H, or R 5 It is an optional substitute for -CO2C 1-6 Alkyl groups, such as -CO2 (glycidyl) groups, or R 5 It is an optional replacement -OC 1-6 Alkyl groups, such as -O (glycidyl) or -O-butyl. Other examples include alternative forms, where R... 5 With R 7 Together with their adjacent carbon atoms, they form 5-membered heterocycles, such as maleic anhydride or maleamide groups.

[0059] Non-limiting examples of salts for the polymer include alkali metal salts and alkaline earth metal salts. For example, salts compatible with other components in an electrochemical cell, such as lithium salts, sodium salts, potassium salts, magnesium salts, etc., can be used. The number-average molecular weight of the polymer can be from 2,000 to 50,000 g / mol, or from 3,000 to 10,000 g / mol.

[0060] For example, the polymers of the present invention can be represented as homopolymers of formula III or salts thereof:

[0061] Formula III

[0062] in, R 1 R 2 and R 3 As defined above; L 1 and L 2 Independently selected from H, alkyl, polymerization initiator residues, and linking groups between two or more polymer chains; and n 1 It is an integer, chosen such that the number-average molecular weight is, for example, 2000 to 50,000 g / mol, or 3000 to 10,000 g / mol, or a salt thereof.

[0063] Examples of linking groups include, but are not limited to, alkyl, alkoxy, and aryl groups, each of which may be further substituted. In one example, L 1 and L 2 It is independently a straight-chain or branched alkyl group, which optionally contains two or more functional groups containing heteroatoms selected from oxygen, nitrogen and sulfur (e.g., including ethers, esters, carboxylate amides, urethanes, ureas, carbonates, their sulfur-containing equivalents, etc.), each connected in a linear, star-shaped or comb-shaped configuration in the polymer chain.

[0064] The polymers of the present invention may also be copolymers, such as random copolymers, block copolymers, star-shaped, branched or hyperbranched copolymers (e.g., including comb-shaped, dendritic, etc.). When the polymer is a copolymer, the copolymer contains at least 10 mol% of monomer units derived from formula I vinylimidazole, or about 10 mol% to about 50 mol%, for example about 20 mol% to about 40 mol%, or about 30 mol%.

[0065] For example, the polymers of the present invention can be represented as random or block copolymers of formula IV, or salts thereof:

[0066] Formula IV

[0067] Where R 1 R 2 R 3 R 4 R 5 R 6 R 7 L 1 and L 2 As defined in this article, n 2 and n 3 This is an integer representing the number of individual monomer units within the polymer, chosen such that the number-average molecular weight is, for example, 2000 to 50,000 g / mol, or about 3000 to about 10,000 g / mol, or a salt thereof. For example, the ratio n 2 :n 3 It can be in the range of 9:1 to 1:1, or 4:1 to 3:2, or about 7:3.

[0068] For example, the polymers of the present invention may be represented as random or block copolymers of formula V, or their salts:

[0069] Formula V

[0070] Where R 1 R 2 R 3 R 4 R5 R 6 R 7 L 1 L 2 n 2 and n 3 As defined in this article; L 3 Selected from linear or branched alkyl groups, and linking groups between polymer chains, such as crosslinkable or crosslinkable monomers; and n 4 and n 5 Each is an integer selected from 1 to 4; Or its salt.

[0071] For example, ratio (n 2 xn 4 ) : (n 3 xn 5 The ratio can be in the range of 9:1 to 1:1, or 4:1 to 3:2, or approximately 7:3. In another example, n 4 + n 5 = 3 or 4.

[0072] In one instance, L 3 Selected from branched alkyl or functionalized branched alkyl, such as pentaerythritol tetra(alkyl ester) derivatives, and other similar compounds.

[0073] The copolymers of the present invention can have different microstructures, such as block copolymers, statistical random copolymers, star copolymers, hyperbranched copolymers, graft copolymers, etc. In some cases, the copolymer may comprise polymers of formula III or IV, and also comprise monomer units containing two or more polymerizable functional groups (e.g., double bonds or other groups), for example having a star or comb-like structure. The copolymer may also further comprise crosslinkable monomer units.

[0074] The polymerization of monomers can be carried out through any known process and initiation method, such as free radical polymerization. When the polymer is a homopolymer, it can be prepared by polymerization as shown in reaction formula 1: Reaction 1

[0075] Where R 1 R 2 L 1 L 2 and n 1This is as defined herein, or a salt of this polymer. The initiator can be any suitable polymerization initiator, such as peroxides (e.g., hydrogen peroxide, benzoyl peroxide, dicumyl peroxide), azo compounds (e.g., azobisisobutyronitrile (AIBN)), persulfates (e.g., potassium persulfate). Polymerization can also be initiated by photolysis, heat treatment, and any other suitable method. For example, polymerization can be initiated by ionizing radiation, electrolysis, etc.

[0076] Synthesis of polymers containing only monomer units derived from formula I, wherein R 1 and R 2 It is CN, and can be carried out in a similar manner to that described in Johnson, DM, et al., Macromolecules 33.23 (2000): 8597-1999.

[0077] Random copolymers can be synthesized via free radical polymerization, as shown in reaction formula 2: Reaction 2

[0078] Where R 1 R 2 R 3 R 4 R 5 R 6 R 7 L 1 L 2 n 2 and n 3 It is as defined herein, or a salt thereof. The initiator is as defined above.

[0079] When the copolymer is a block copolymer, its synthesis can be carried out by reversible addition-chain transfer polymerization (or RAFT). An example of a RAFT reagent is S,S-dibenzyl trithiocarbonate, as shown in reaction 3, particularly for acrylic acid. Other known RAFT reagents can also be used.

[0080] Reaction 3

[0081] The polymer can also be prepared and used as its metal salt form as described above, for example as a lithium salt, and dissolved in water, or as an alkaline (neutral) form dissolved in NMP, MeCN, DMF or DMSO, for application onto a carrier.

[0082] Block and star copolymer structures can be obtained through controlled radical polymerization, including RAFT polymerization, oxynitride-regulated radical polymerization, and atom transfer radical polymerization.

[0083] Reaction 4 shows an example of a star copolymerization method. This example involves first polymerizing acrylic acid with a star-shaped RAFT reagent, namely pentaerythritol tetrakis[2-(dodecylthiocarbonylthio)-2-methylpropionate]. The individual wavy lines represent polymer chains as defined herein; for clarity, only one such polymer chain is shown here.

[0084] Reaction 4

[0085] This invention also relates to electrode materials comprising polymers and electrochemically active materials as defined herein, such as in particle form. The electrochemically active material can be used in either the negative or positive electrode. Non-limiting examples of electrochemically active materials include titanates and lithium titanates (e.g., TiO2, Li2TiO3, Li4Ti5O3). 12 H2Ti5O 11 The active materials can be lithium metal phosphates and metal phosphates (e.g., LiM'PO4 and M'PO4, where M' is Fe, Ni, Mn, Co, or a combination thereof), vanadium oxides (e.g., LiV3O8, V2O5, LiV2O5, etc.), and other lithium and metal oxides such as LiMn2O4, LiM''O2 (M'' is Mn, Co, Ni, or a combination thereof), Li(NiM''')O2 (M''' is Mn, Co, Al, Fe, Cr, Ti, Zr, etc., or a combination thereof), or any combination of the above materials when compatible. For example, the active material is selected from lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium titanate (LTO), graphite, and lithium nickel manganese cobalt oxide (NMC). Other electrochemical active materials may also include carbon sources, such as graphite. The particles can be freshly made or from commercially available sources, in the form of microparticles or nanoparticles, and may also include coatings, such as carbon coatings.

[0086] Electrode materials may also optionally include additional components such as conductive materials, salts, inorganic particles, glass or ceramic particles, etc. Examples of conductive materials include carbon black, Ketjen™ black, acetylene black, graphite, graphene, carbon fibers, nanofibers (e.g., VGCF) or nanotubes, or combinations thereof.

[0087] Electrodes incorporating the electrode materials of this invention can be manufactured as follows: An electrode composition comprising an electrochemically active material, a polymer as defined herein, and optional additional elements, including conductive agents, etc., is prepared. The preparation of the electrode material can be carried out by dry mixing or wet mixing (e.g., in the presence of a solvent), for example by mechanical melting, planetary mixers, etc. This composition is then applied to a carrier (e.g., a current collector), for example by spreader application, by casting, coating, dip coating, extrusion, calendering, and other methods known in the art. In the case of wet mixing, the electrode material is then dried to remove any trace amounts of solvent used during the mixing step. Drying may include an initial heating step at atmospheric pressure, followed by a drying step under vacuum.

[0088] When used in electrode binders, the concentration of the polymer described herein (the first polymer) can be up to 10% by weight or up to 5% by weight based on the total weight of the electrode material, with a concentration of 0.1-5% by weight, 0.4-3% by weight, 0.5-2% by weight, or 1-2% by weight. The binder composition may also contain a second polymer, such as polymers selected from monomers based on glycidyl groups, acrylic or methacrylic acid, vinyl alkyl ethers, thiols, etc. For example, the second polymer is a polymer containing monomer units based on Formula II compounds, which does not contain monomer units derived from Formula I vinylimidazole, such as a homopolymer of monomer units based on Formula II compounds. In one example, the second polymer is a polyacrylic acid or polymethacrylic acid polymer, preferably polyacrylic acid. In other examples, the second polymer is selected from fluoropolymers (e.g., PVdF, PTFE, etc.), water-soluble adhesives (e.g., SBR (styrene-butadiene rubber), NBR (butadiene-acrylonitrile rubber), HNBR (hydrogenated NBR), CHR (epicochlorohydrin rubber), ACM (acrylate rubber)), cellulose-based adhesives (e.g., carboxyalkyl cellulose, hydroxyalkyl cellulose, and combinations thereof), or any combination of two or more of these substances. For example, carboxyalkyl cellulose can be carboxymethyl cellulose (CMC) or carboxyethyl cellulose. Other examples of the second polymer include ion-conducting polymer adhesives, such as block copolymers consisting of at least one lithium-ion solvated segment and at least one crosslinkable segment (e.g., PEO-based polymers containing methyl methacrylate units). The weight ratio between the first polymer (as defined herein) and the second polymer can range from 1:9 to 7:3, or from 1:4 to 3:2, or from about 1:3 to about 1:1, or from about 1:2 to about 1:1.

[0089] The second polymer can be used, for example, to modulate one or more properties of the electrode material, such as the adhesion of the electrode material to adjacent elements of the battery, such as current collectors and / or polymer electrolytes. A combination of the two polymers can provide a balance between adhesion and flexibility.

[0090] The polymer can also be used in compositions for coating particles of the electrochemically active material described herein, i.e., coating compositions that serve as the shell in a core-shell structure. The shell composition may contain the polymer as defined herein at concentrations, for example, 5-100% by weight, or 10-50% by weight, or 25-75% by weight, or 50-100% by weight, or 5-25% by weight, or 40-75% by weight. Such a shell composition may also contain additional components as described for the binder compositions above. When the polymer of the present invention is used as the shell composition, the electrode compositions herein may also contain a binder, with or without the polymer as defined herein.

[0091] The polymers of this invention can also be used in electrolyte compositions, for example, in gel or solid polymer electrolytes. For example, the concentration of the polymers of this invention in the electrolyte composition can be up to 50% by weight, up to 10% by weight, or up to 5% by weight, with concentrations of 0.1-5% by weight, 0.4-3% by weight, 0.5-2% by weight, or 1-2% by weight. For example, the electrolyte composition may also contain a second polymer. Examples of second electrolyte polymers include those described above for binder compositions. For example, the second polymer electrolyte can be a PEO-based polymer, PVdF, CMC, or PVA (polyvinyl acetate). Other examples of polymers that can be used as a second polymer in the electrolyte composition are, for example, polyethylene glycol-based polymers, such as polyethylene glycol methacrylate or methacrylate, etc. Various additives can also be included in the polymer electrolyte composition to improve its performance, including salts compatible with other components or inorganic materials of the electrochemical battery.

[0092] This invention also relates to electrochemical cells and battery packs comprising them, wherein at least one element of the electrochemical cell comprises the polymer of this invention. Such an element may be an electrode material, an electrolyte composition, or a counter electrode material. In one example, the electrode comprises an electrode material as defined herein. In another example, the electrolyte comprises an electrolyte composition as defined herein. In yet another example, the electrode comprises an electrode material as defined herein, and the electrolyte comprises an electrolyte composition as defined herein. In yet another example, the electrode and counter electrode each independently comprise an electrode material as defined herein. In yet another example, the electrode and counter electrode each independently comprise an electrode material as defined herein, and the electrolyte comprises an electrolyte composition as defined herein. For example, the battery is a lithium or lithium-ion battery, such as a rechargeable battery. In other examples, the battery is a sodium or potassium battery.

[0093] When one of the electrode materials or the counter electrode materials contains a polymer as defined herein, the electrolyte can be a liquid, gel, or solid electrolyte compatible with the electrochemically active materials of the electrode and counter electrode. For example, when the electrolyte is a liquid electrolyte containing a salt dissolved in an electrolyte solvent, the electrolyte may also contain a separator. The electrolyte can also be a solid or gel solution of a salt in a polar solvated polymer. Examples of electrolyte salts include lithium salts such as LiTFSI, LiPF6, LiDCTA, LiBETI, LiFSI, LiBF4, LiBOB, and combinations thereof. Examples of solid polar solvated polymers include linear, branched, and / or crosslinked polyether polymers, such as those based on polyethylene oxide (PEO), polypropylene oxide (PPO), or mixtures thereof, optionally also containing crosslinkable units.

[0094] Other additives can be present in the electrolyte composition, such as glass particles, ceramics, such as nanoceramics (e.g., Al2O3, TiO2, SiO2, and other similar compounds). These additives can be incorporated into the polymer electrolyte matrix to improve its mechanical properties, thereby limiting the formation of dendrites of salts (Li, Na, etc.) during charging.

[0095] Furthermore, the electrochemically active material of the counter electrode can be selected from any known material, including the aforementioned electrochemically active materials (selected for redox compatibility with the electrode active material) and alkali metal films, such as lithium metal films or alloys thereof. As contemplated, when the counter electrode material consists of a film of metallic material, it may not contain the polymer of the present invention.

[0096] In one example, the electrode electrochemically active material comprises lithium metal phosphate or metal phosphate (e.g., LiFePO4, LiMnPO4, LiMnFePO4, etc.), and the electrode electrochemically active material comprises titanate or lithium titanate (e.g., Li4Ti5O4). 12 In another example, the electrode electrochemical active material comprises lithium metal phosphate or metal phosphate, and the counter electrode electrochemical active material comprises a lithium metal film.

[0097] According to another aspect, the present invention discloses the use of electrochemical batteries as defined herein in electric or hybrid vehicles, or in ubiquitous information technology devices. For example, contemplated applications include portable devices such as mobile phones, cameras, tablets, or mobile computers, electric or hybrid vehicles, or in the storage of renewable energy.

[0098] Example

[0099] The following non-limiting embodiments are illustrative implementations and should not be construed as further limiting the scope of the invention. These embodiments can be better understood with reference to the accompanying drawings.

[0100] Example 1: Homopolymer

[0101] (a) Homopolymerization of 2-vinyl-4,5-dicyanimidazole: This example illustrates the homopolymerization of 2-vinyl-4,5-dicyanimidazole. To perform this polymerization, 1.5 g of the vinylimidazole derivative and 50 mL of acetonitrile or dioxane were added to a round-bottom flask, and the solution was bubbled with nitrogen for 30 minutes to remove oxygen. Then, 58 mg of AIBN was added, and the solution was heated to 70°C under nitrogen for at least 12 hours. The polymer was then purified by precipitation in a 10-fold volume mixture of hexane and diethyl ether (2:1) or toluene, separated, and vacuum dried for 12 hours.

[0102] The standard yield obtained using the process described in Example 1(a) is approximately 95%.

[0103] (b) Homopolymerization of lithium-ionized 2-vinyl-4,5-dicyanimidazole: This example illustrates the homopolymerization of lithium-ionized 2-vinyl-4,5-dicyanimidazole. To perform this polymerization, 1.5 g of the vinylimidazole derivative, 0.4 g of lithium hydroxide, and 20 mL of softened water were added to a round-bottom flask. The solution was stirred at room temperature for 1 hour, then bubbled with nitrogen for 30 minutes to remove oxygen. Then, 36 mg of potassium persulfate (KPS) was added, and the solution was heated to 90°C under nitrogen for at least 24 hours. The polymer was then purified by precipitation in 10 times its volume of acetonitrile, separated, and vacuum dried for 12 hours.

[0104] Example 2: Copolymerization

[0105] (a) Random copolymerization of 2-vinyl-4,5-dicyanimidazole and acrylic acid: This example illustrates the copolymerization of 2-vinyl-4,5-dicyanimidazole and acrylic acid. To perform this copolymerization, 0.40 g of the vinylimidazole derivative, 0.50 g of acrylic acid, and 15 mL of acetonitrile or dioxane were added to a round-bottom flask. This solution was bubbled with nitrogen for 30 minutes to remove oxygen. Then, 12 mg of AIBN was added, and the solution was heated to 70°C under nitrogen for at least 12 hours. The polymer was then purified by precipitation in a mixture of 10 times its volume of hexane and diethyl ether (2:1) or toluene, separated, and vacuum dried for 12 hours.

[0106] The standard yield obtained using the process described in Example 2(a) is approximately 50-60%.

[0107] (b) Random copolymerization of lithium-ionized 2-vinyl-4,5-dicyanimidazole and acrylic acid: This example illustrates the random copolymerization of lithium-ionized 2-vinyl-4,5-dicyanimidazole and acrylic acid. To perform this copolymerization, 0.40 g of the vinylimidazole derivative, 0.26 g of lithium hydroxide monohydrate, and 50 mL of softened water were added to a round-bottom flask. The solution was stirred at room temperature for 1 hour to dissolve the imidazole derivative in the water. Once dissolved, 0.50 g of acrylic acid was added to the round-bottom flask, and the resulting solution was bubbled with nitrogen for 30 minutes to remove oxygen. Then, 25 mg of KPS was added, and the solution was heated to 80°C under nitrogen for at least 48 hours. The polymer obtained from this process was then purified by precipitation in 10 times its volume of acetonitrile and vacuum dried for 12 hours.

[0108] The standard yield obtained using the process described in Example 2(b) is approximately 74%.

[0109] (c) Block copolymerization of 2-vinyl-4,5-dicyanimidazole and acrylic acid: This process comprises two steps, the first of which involves block copolymerization of polyacrylic acid via RAFT polymerization. For this copolymerization, 3.09 g of acrylic acid, 0.102 g of S,S-dibenzyl trithiocarbonate (RAFT CTA), and 15 mL of dioxane are added to a round-bottom flask. This solution is stirred at room temperature and bubbled under nitrogen for 30 minutes to remove oxygen. Then, 31.8 mg of AIBN is added, and the solution is heated to 80°C under nitrogen for at least 6 hours. The polymer is then purified by precipitation in 10 times its volume of hexane or toluene and dried under vacuum for 12 hours.

[0110] The second step involves forming a second block containing a vinylimidazole monomer unit. In this step, 1.0 g of the previous polymer (PAA-RAFT), 2.0 g of the imidazole derivative, and 50 ml of dioxane are added to a round-bottom flask. This solution is stirred at room temperature and bubbled under nitrogen for 30 minutes to remove oxygen. Then, 47 mg of AIBN is added to the reaction mixture, and the solution is heated to 90 °C under nitrogen for at least 24 hours. The polymer is then purified by precipitation in a mixture of 10 times its volume of hexane and diethyl ether (2:1) and dried under vacuum for 12 hours.

[0111] The standard yield obtained using the process described in Example 2(c) is approximately 82%.

[0112] Example 3: Star copolymerization of block copolymers of 2-vinyl-4,5-dicyanimidazole and acrylic acid

[0113] This method is a two-step process, the first step of which describes the block copolymerization of polyacrylic acid via RAFT polymerization. For this copolymerization, 3.09 g of acrylic acid, 0.104 g of the four-arm RAFT reagent pentaerythritol tetrakis[2-(dodecylthiocarbonylthio)-2-methylpropionate] (DDMAT RAFT), and 15 mL of dioxane were added to a round-bottom flask. This solution was stirred at room temperature and bubbled under nitrogen for 30 minutes to remove oxygen. Then, 31.8 mg of the initiator AIBN was added, and the solution was heated to 80 °C under nitrogen for at least 6 hours. The polymer was then purified by precipitation in 10 times its volume of hexane or toluene and dried under vacuum at 80 °C for 12 hours. The polymer was stored at 4 °C.

[0114] The second step of Example 3 describes the formation of a second block containing vinylimidazole. This preparation involved adding 1.0 g of the previous polymer (PAA-RAFT), 2.0 g of the imidazole derivative, and 50 ml of dioxane to a round-bottom flask. The solution was stirred at room temperature and bubbled with nitrogen for 30 minutes to remove oxygen. Then, 47 mg of the initiator AIBN was added to the flask, and the solution was heated to 90°C under nitrogen for at least 24 hours. The polymer was then purified by precipitation in a mixture of 10 times its volume of hexane and diethyl ether (2:1) and dried under vacuum at 60°C for 12 hours.

[0115] Example 4: Manufacturing a Battery

[0116] (a) Cathode

[0117] Examples of cathodes (C3, C4, and C6) and reference cathodes (C1, C2, and C5) containing the polymers described herein, manufactured according to the weight ratios shown in Table 1.

[0118] Table 1. Weight concentration of cathode material

[0119] a.EAM: Electrochemically active material, LFP: LiFePO4

[0120] b. PAA: 450,000 g / mol

[0121] This material was prepared by mixing electrochemically active materials, carbon, and polymers in a solvent to obtain a slurry using a planetary centrifugal degassing mixer from Thinky Corporation. NMP was used as the solvent in preparing the materials for cathodes C1, C3, and C5, while water was used as the solvent for cathodes C2, C4, and C6. In the preparation of cathode C3, PAA and polymer 1 were used as solutions in NMP at concentrations of 11% and 10%, respectively. Similarly, in the preparation of cathode C4, PAA and polymer 1 were used as aqueous solutions at concentrations of 10% and 6.5%, respectively. The resulting slurry was then cast onto an aluminum current collector using a doctor blade and dried.

[0122] (b) Anode

[0123] Examples of anodes (A2) and reference anodes (A1) for comparison, containing polymers as defined herein, manufactured according to the weight ratios shown in Table 2.

[0124] Table 2. Weight concentration of anode materials

[0125] a.EAM: Electrochemically active material, LTO: Li4Ti5O 12

[0126] The anode material is prepared by mixing electrochemically active materials, carbon, and polymers in water to obtain a slurry using a planetary centrifugal degassing mixer from Thinky Corporation. In the preparation of anode A2 material, polymer 1 is used as a solution in water at a concentration of 6.5%. The resulting slurry is then cast onto an aluminum current collector using a scraper method and dried.

[0127] (c) Battery

[0128] All batteries are assembled using standard 2032-sized button cell casings (i.e., 20 mm in diameter and 3.2 mm in height), with 16 μm polyethylene separators impregnated in a 1 mol / kg LiPF6 solution in PC / DMC / EMC (4:3:3) as the liquid electrolyte.

[0129] Table 3. Structure of LFP / LTO batteries

[0130] A battery or half-cell containing cathode material C3, cathode material C1 (comparison), anode material A3 or anode material A4 (comparison), and a lithium metal counter electrode is also assembled as described in this embodiment.

[0131] Example 5: Electrochemical Performance

[0132] Prior to the electrochemical experiments, the LFP / LTO, LFP / Li, and LTO / Li half-cells were subjected to two charge-discharge cycles at 0.2 C and 25 °C.

[0133] In this embodiment, xC is the current at which the battery reaches full charge / discharge capacity in 1 / x hours. For example, 1C, 2C, 4C, and 10C each represent the current at full capacity during charging or discharging in 1 hour, 30 minutes, 15 minutes, and 6 minutes, respectively.

[0134] For LFP / Li batteries, charging is performed in constant current-constant voltage (CC-CV) mode with a voltage of 3.9V, a current of 0.2C, and a cutoff current of 0.03 mA. Discharging is performed in constant current (CC) mode with a cutoff voltage of 2.0V and a current of 0.2C.

[0135] For LTO / Li half-cells, charging is performed in CC-CV mode with a voltage of 1.0 V, a current of 0.2 C, and a cutoff current of 0.03 mA. Discharging is performed in CC mode with a cutoff voltage of 2.7 V and a current of 0.2 C.

[0136] For LFP / LTO batteries, charging is performed in CC-CV mode with a voltage of 2.4 V, a current of 0.2 C, and a cutoff current of 0.03 mA. Discharging is performed in CC mode with a cutoff voltage of 0.5 V and a current of 0.2 C.

[0137] Loading test of P(AA-copoly-2-vinyl-4,5-dicyanimidazolium)

[0138] The effect of PAA-2-vinyl-4,5-dicyanimidazol on power performance was determined by load tests.

[0139] The LFP / Li battery was assembled as described in Example 4, comprising either cathode C3 or cathode C1 (comparison). It was then charged and discharged at 0.2 C, 1.0 C, 4.0 C, and 10.0 C. Subsequently, the battery underwent a full charge and discharge cycle at 0.2 C.

[0140] The LFP / LTO battery was assembled as described in Example 4, and then charged and discharged at 0.2 C, 1.0 C, 4.0 C, and 10.0 C. Subsequently, the battery was fully charged and discharged again at 0.2 C.

[0141] To conduct the charge load test, the LFP / LTO and LFP / Li batteries were fully discharged at 0.2 C, then charged at 1 C, and then charged again at 0.2 C. These batteries were then discharged at 0.2 C and charged at 2 C.

[0142] To conduct discharge load tests, the LFP / LTO and LFP / Li batteries were fully charged at 0.2 C, then discharged at 1 C, and then discharged again at 0.2 C. These batteries were then charged at 0.2 C and discharged at 2 C.

[0143] Calculate the capacity retention percentage using the following formula: Capacity retention (%) = [(Capacity at xC) / (Capacity at 0.2C)] x 100 (1) For LFP / Li batteries, the capacity in the CC region is used to calculate the charge load characteristics. A second charge is then performed in CC-CV mode with a voltage of 2.4V, a current of xC, and a cutoff current of 0.03 mA. Discharge is then performed in CC mode with a cutoff voltage of 0.5V and a current of xC.

[0144] For LFP / LTO batteries, the capacity in the CC region is used to calculate the charge load characteristics. A second charge is then performed in CC-CV mode with a voltage of 2.4V, a current of xC, and a cutoff current of 0.03 mA. Discharge is then performed in CC mode with a cutoff voltage of 0.5V and a current of xC.

[0145] a) Impedance

[0146] LFP / Li batteries

[0147] Electrochemical impedance spectroscopy (EIS) was performed on an LFP / Li cell. Figure 1 This shows the impedance spectrum recorded using this system at 25°C. For example... Figure 1 As shown, compared with a reference LFP / Li cell containing cathode material C1 using PVDF as a binder, the LFP / Li cell containing cathode material C3 manufactured according to the process described in Example 4 exhibits a smaller resistance at 25°C.

[0148] LTO / Li half-cell

[0149] EIS testing was also performed on the LTO / Li half-cell. Figure 2 This shows the impedance spectrum recorded using this system at 25°C. For example... Figure 2As shown, the LTO / Li half-cell containing anode material A3 manufactured according to the process described in Example 4 exhibits lower resistance compared to a reference LTO / Li half-cell containing anode material A4 using CMC / SBR binder.

[0150] LFP / LTO batteries

[0151] like Figure 3 As shown, compared to the LFP (battery 1) using PVDF as a binder, the battery 3 manufactured according to the process described in Example 4 exhibits a lower resistance at 25°C. Regarding the resistance at the end of the reference half-cycle, it is 4.5 Ohm for battery 1 and 1.0 Ohm for battery 3. EIS testing was performed using the aforementioned LFP / LTO button cell at 50% charge, with a frequency range of 1 MHz to 10 mHz and an AC amplitude of 10 mV.

[0152] Table 4 Impedance

[0153] b) Impedance at low temperature

[0154] The positive effects of the 2-vinyl-4,5-dicyanimidazolium monomer in the polymer were also observed at low temperatures. Figure 4 The Nyquist plot is shown at -30°C. The resistance at the end of the reference half-cycle is 19 Ohms for battery 1 and 11 Ohms for battery 3. EIS was performed using the aforementioned LFP / LTO coin cells at 50% charge, with a frequency range of 1MHz to 10mHz and an AC amplitude of 10mV.

[0155] c) Capacity retention of LFP / Li batteries after charge-discharge cycles

[0156] The effect of PAA-2-vinyl-4,5-dicyanimidazolium on the power performance of LFP / Li batteries was determined by load tests. Figure 5 The graphs show the charge (a) and discharge (b) load characteristics of an LFP / Li cell containing cathode material C3 (i.e., containing P(AA-copoly-2-vinyl-4,5-dicyanimidazolium)) and a reference LFP / Li cell containing cathode material C1 using PVDF as a binder. Capacity retention after charge-discharge cycles was recorded at 25°C and evaluated at different charge and discharge rates (1C, 2C, and 4C). Figure 5 As shown, the presence of PAA-2-vinyl-4,5-dicyanimidazolium in LFP / Li batteries has a significant impact on capacity retention, and this impact is even greater at high charge and discharge rates.

[0157] d) Capacity retention of LFP / LTO batteries after charge-discharge cycles at different temperatures

[0158] At 25°C and under high charge and discharge rates (4C and 10C), 2-vinyl-4,5-dicyanimidazole (Vinazene) also significantly affects capacity retention, as shown in... Figure 6 (a) and (b) show the LFP / LTO coin cells (cell 4 compared to cells 5 and 6).

[0159] After heating the battery at 45°C, the effect of 2-vinyl-4,5-dicyanimidazole on capacity retention became even greater, as shown in... Figure 7 (a) and (b) show the LFP / LTO button cell (comparison of cell 1 and cell 3 after heating at 45°C).

[0160] Figure 8 The effect of 2-vinyl-4,5-dicyanimidazole on capacity retention is shown for LFP / LTO coin cells when the cells are charged (a) and discharged (b) at a low temperature of -15°C (cell 1 vs. cell 3 and cell 3 after being heated at 45°C). While not as in... Figure 6 and 7 While not as significant as in the meantime, differences in capacity retention at high charge and discharge rates (4C) can still be observed at low temperatures.

[0161] When used in anode materials, the effect of 2-vinyl-4,5-dicyanimidazole on capacity retention is also significant at high charge and discharge rates (4C and 10C) at 25°C, such as in... Figure 9 (a) and (b) show the LFP / LTO coin cells (cell 1 compared to cell 7). This is also more pronounced when discharging.

[0162] e) Effect of temperature on H-bonding

[0163] The polymer was stirred with a 1-equivalent lithium salt solution at 25°C for 1 hour, and then dried. Fourier transform infrared spectroscopy (FTIR) analysis was performed; the spectrum is shown below. Figure 10 As shown.

[0164] The polymer was stirred with a 1-equivalent lithium salt solution at 45°C for 1 hour, and then dried. FTIR analysis was performed, and the spectrum is shown below. Figure 11 As shown. Figure 11 Spectra and Figure 10 The spectra are clearly different. The hydrogen bond peak is significantly weaker, indicating lithium ion coordination. Furthermore, Figure 11 It also shows a comparison Figure 10 Less NH bending.

[0165] Many changes may be made to any of the above embodiments without departing from the scope of the invention. The entire contents of any documents, patents, or technical files mentioned herein are incorporated herein by reference.

Claims

1. An element of an electrochemical cell comprising a polymer containing monomer units derived from formulas I and II: in, R 1 and R 2 Each is independently selected from H, CN, F and optionally fluorinated C. 1-6 Alkyl group, wherein R 1 and R 2 At least one of them is CN; R 3 Selected from hydrogen atoms and optionally substituted C atoms 1-6 alkyl; R 4 R 6 and R 7 Each is independently selected from hydrogen atoms and optionally substituted C atoms. 1-6 Alkyl; and R 5 Selected from -CO2H, with optional substitution of -CO2C 1-6 Alkyl, -C(O)NH2, optionally substituted -OC 1-6 Alkyl, optionally substituted C6 aryl, optionally substituted C 5-6 Heteroaryl, -CN, -SO3H, -SO2NH2, and optionally substituted -SO3C 1-6 Alkyl; or R 5 With R 7 Together with their adjacent carbon atoms, they form 5- or 6-membered heterocycles; Or a salt of the polymer.

2. The element of the electrochemical cell of claim 1, wherein R 1 It is CN, and R 2 It is an optional fluorinated C 1-6 alkyl.

3. The element of the electrochemical cell of claim 1, wherein R 2 It is CN, and R 1 It is an optional fluorinated C 1-6 alkyl.

4. The element of the electrochemical cell of claim 1, wherein R 1 and R 2 They are all CN.

5. An element of the electrochemical cell according to any one of claims 1-4, wherein R 3 It's H.

6. An element of the electrochemical cell according to any one of claims 1-4, wherein R 3 C is an optional substitute 1-6 alkyl.

7. The polymer of claim 6, wherein R 3 It is a methyl group.

8. An element of an electrochemical cell according to any one of claims 1-4, wherein R 4 R 6 and R 7 At least one of them is H.

9. The element of the electrochemical cell of claim 8, wherein R 4 It's H.

10. The element of the electrochemical cell of claim 8, wherein R 4 R 6 and R 7 The two in it are H.

11. The element of the electrochemical cell of claim 8, wherein R 4 R 6 and R 7 It's H.

12. An element of an electrochemical cell according to any one of claims 1-4, wherein R 4 C is an optional substitute 1-6 alkyl.

13. The element of the electrochemical cell of claim 12, wherein R 4 It is a methyl group.

14. An element of an electrochemical cell according to any one of claims 1-4, wherein R 5 It is CO2H.

15. An element of an electrochemical cell according to any one of claims 1-4, wherein R 5 It is an optional substitute for -CO2C 1-6 alkyl.

16. The element of the electrochemical cell of claim 15, wherein R 5 It is a -CO2 (glycidyl) group.

17. An element of an electrochemical cell according to any one of claims 1-4, wherein R 5 It is an optional replacement -OC 1-6 alkyl.

18. The element of the electrochemical cell of claim 17, wherein R 5 It is -O (glycidyl group).

19. The element of the electrochemical cell of claim 17, wherein R 5 It is -O-butyl.

20. An element of an electrochemical cell according to any one of claims 1-4, wherein R 5 With R 7 Together with their adjacent carbon atoms, they form 5-membered heterocycles.

21. The element of the electrochemical cell of claim 20, wherein R 5 With R 7 Together with their adjacent carbon atoms, they form maleic anhydride groups.

22. The element of the electrochemical cell of claim 20, wherein R 5 With R 7 Together with their adjacent carbon atoms, they form maleamide groups.

23. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer comprises 10-90 mol% of monomer units derived from a vinylimidazolium derivative of formula I, including an upper limit and a lower limit for each.

24. An element of the electrochemical cell of claim 23, wherein the polymer comprises 10-60 mol% of monomer units derived from a vinylimidazolium derivative of formula I, including an upper limit and a lower limit for each.

25. An element of the electrochemical cell of claim 23, wherein the polymer comprises 15-40 mol% of monomer units derived from a vinylimidazolium derivative of formula I, including an upper limit and a lower limit for each.

26. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer is a random or block copolymer of formula IV: in, R 1 To R 7 It is as defined in any one of claims 1-4; L 1 and L 2 Independently selected from H, alkyl, polymerization initiator residues, and linking groups between two or more polymer chains; and n 2 and n 3 n is an integer representing the number of individual monomer units within the polymer, and n is chosen as the number of monomer units. 2 and n 3 So that the number-average molecular weight is about 2,000 to about 50,000 g / mol, or about 3,000 to about 10,000 g / mol; and the ratio n 2 :n 3 It falls within the range of 9:1 to 1:1; Or a salt of the polymer.

27. The element of the electrochemical cell of claim 26, wherein the ratio n 2 :n 3 It falls within the range of 4:1 to 3:

2.

28. The element of the electrochemical cell of claim 26, wherein the ratio n 2 :n 3 It is John 7:

3.

29. An element of an electrochemical cell according to any one of claims 1-4, wherein said polymer is a random or block copolymer of formula V: in, R 1 To R 7 It is as defined in any one of claims 1-4; L 1 and L 2 Independently selected from H, alkyl, polymerization initiator residues, and linking groups between two or more polymer chains; n 2 and n 3 n is an integer representing the number of individual monomer units within the polymer, and n is chosen as the number of monomer units. 2 and n 3 So that the number-average molecular weight is about 2,000 to about 50,000 g / mol, or about 3,000 to about 10,000 g / mol; and the ratio n 2 :n 3 It falls within the range of 9:1 to 1:1; n 4 and n 5 Each option is selected from 1 to 4, where n is selected. 2 n 3 n 4 and n 5 So that the number-average molecular weight is about 2,000 to about 50,000 g / mol, or about 3,000 to about 10,000 g / mol, and the ratio (n) 2 xn 4 ):(n 3 xn 5 () is in the range of 9:1 to 1:1; and L 3 It is selected from linear or branched alkyl groups and linking groups between polymer chains, such as crosslinkable monomers or crosslinked monomers; Or a salt of the polymer.

30. The element of the electrochemical cell of claim 29, wherein the ratio (n) 2 xn 4 ):(n 3 xn 5 The ratio is in the range of 4:1 to 3:

2.

31. The element of the electrochemical cell of claim 29, wherein the ratio (n) 2 xn 4 ):(n 3 xn 5 The total is approximately 7:

3.

32. The element of the electrochemical cell of claim 29, wherein n 4 + n 5 = 3 or 4.

33. The element of the electrochemical cell of claim 29, wherein L 3 It is selected from branched alkyl groups, functionalized branched alkyl groups, and other similar compounds.

34. The element of the electrochemical cell of claim 33, wherein L 3 It is a pentaerythritol tetra(alkyl ester) derivative.

35. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer is a random copolymer.

36. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer is a block copolymer.

37. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer is a branched or hyperbranched copolymer, including comb copolymers and dendritic copolymers.

38. An element of an electrochemical cell according to any one of claims 1-4, wherein the polymer is a star copolymer.

39. The element of the electrochemical cell of claim 38, wherein the linear chains of the star copolymer are uniform in length and structure.

40. The element of the electrochemical cell of claim 38, wherein the linear chains of the star copolymer are non-uniform in length and structure.

41. The element of the electrochemical cell of claim 38, wherein the linear chain of the star copolymer is a block copolymer.

42. The element of the electrochemical cell of claim 38, wherein in the random copolymer, the linear chain of the star copolymer is a random copolymer.

43. An element of an electrochemical cell comprising a polymer containing monomer units derived from Formula I: Formula I in, R 1 and R 2 Each is independently selected from H, CN, F and optionally fluorinated C. 1-6 Alkyl group, wherein R 1 and R 2 At least one of them is CN; and R 3 Selected from hydrogen atoms and optionally substituted C atoms 1-6 alkyl; Or a salt of the polymer.

44. The element of the electrochemical cell of claim 43, wherein R 1 It is CN, and R 2 It is an optional fluorinated C 1-6 alkyl.

45. The element of the electrochemical cell of claim 43, wherein R 2 It is CN, and R 1 It is an optional fluorinated C 1-6 alkyl.

46. ​​The element of the electrochemical cell of claim 43, wherein R 1 and R 2 They are all CN.

47. An element of an electrochemical cell according to any one of claims 43-46, wherein R 3 It's H.

48. An element of an electrochemical cell according to any one of claims 43-46, wherein R 3 C is an optional substitute 1-6 alkyl.

49. The element of the electrochemical cell of claim 48, wherein R 3 It is a methyl group.

50. An element of an electrochemical cell according to any one of claims 43-46, wherein said polymer is a homopolymer of formula III: in, R 1 R 2 and R 3 It is as defined in any one of claims 43-46; L 1 and L 2 Independently selected from H, alkyl, polymerization initiator residues, and linking groups between two or more polymer chains; and n 1 The number is an integer, chosen such that the number-average molecular weight is about 2,000 to about 50,000 g / mol, or 3,000 to 10,000 g / mol; Or a salt of the polymer.

51. An element of the electrochemical cell of claim 50, wherein the connecting base L 1 and L 2 It is selected from alkyl, alkoxy and aryl groups, each of which can be further substituted.

52. An element of the electrochemical cell of claim 50, wherein the connecting base L 1 and L 2 It's a linear chain.

53. An element of the electrochemical cell of claim 50, wherein the connecting base L 1 and L 2 It is branched.

54. The element of the electrochemical cell of claim 50, wherein the connecting base is L 1 and L 2 A functional group, which optionally comprises two or more functional groups containing heteroatoms selected from oxygen, nitrogen, and sulfur.

55. The polymer of claim 54, wherein the functional group comprises ethers, esters, carboxylic amides, urethanes, ureas, carbonates and their sulfur-containing equivalents, each connected in a linear, star-shaped or comb-shaped configuration in the polymer chain.

56. An element of an electrochemical cell according to any one of claims 1-4, wherein the salt of said polymer comprises an alkali metal salt and an alkaline earth metal salt.

57. An element of the electrochemical battery of claim 56, wherein the salt of said polymer is a lithium salt.

58. An element of the electrochemical cell of claim 56, wherein the salt of said polymer is a sodium salt.

59. The element of the electrochemical cell of claim 56, wherein the salt of said polymer is a potassium salt.

60. An element of the electrochemical cell of claim 56, wherein the salt of said polymer is a magnesium salt.

61. An element of an electrochemical cell according to any one of claims 1-4, which is used in an electrode material, in an electrolyte composition and / or in a separator.

62. An electrode material, wherein the electrode material is an element of an electrochemical cell as defined in any one of claims 1-61, and comprises an electrochemically active material.

63. The electrode material of claim 62, wherein the polymer is a binder.

64. The electrode material of claim 63, wherein the concentration of the polymer binder is at most 10% by weight or at most 5% by weight, or 0.1-5% by weight, or 0.4-3% by weight, 0.5-2% by weight or 1-2% by weight, based on the total weight of the electrode material.

65. The electrode material of claim 63 or 64, wherein the adhesive further comprises a second polymer selected from: polymers based on glycidyl groups, acrylic or methacrylic acid, vinyl alkyl ethers, thiol-containing monomers, fluoropolymers, water-soluble adhesives, styrene-butadiene rubber, butadiene-acrylonitrile rubber, hydrogenated butadiene-acrylonitrile rubber, epichlorohydrin rubber, acrylate rubber, cellulose-based adhesives, ion-conducting polymer adhesives, and any combination of two or more of these materials.

66. The electrode material of claim 63 or 64, wherein the second polymer is polyacrylic acid.

67. The electrode material of claim 63 or 64, wherein the second polymer is polyvinylidene fluoride.

68. The electrode material of claim 63 or 64, wherein the second polymer is carboxymethyl cellulose.

69. The electrode material of claim 63 or 64, wherein the second polymer is styrene-butadiene rubber.

70. The electrode material of claim 63 or 64, wherein the second polymer is a block copolymer consisting of at least one lithium-ion solvable segment and at least one crosslinkable segment.

71. The electrode material of claim 70, wherein the second polymer is a PEO-based polymer comprising methyl methacrylate units.

72. The electrode material of claim 62, wherein the electrode material comprises particles having a core-shell structure, and wherein the core comprises a coating composition containing the polymer, and the core comprises an electrochemically active material.

73. The electrode material of claim 72, wherein the shell composition comprises the polymer at a concentration of 5-100% by weight, or the concentration of the polymer is 10-50% by weight, or 25-75% by weight, or 50-100% by weight, or 5-25% by weight, or 40-75% by weight.

74. The electrode material of claim 72 or 73, wherein the electrode material further comprises an adhesive.

75. The electrode material of claim 62, wherein the electrode is a positive electrode.

76. The electrode material of claim 62, wherein the electrode is a negative electrode.

77. An electrolyte, wherein the electrolyte is an element of an electrochemical cell as defined in any one of claims 1-61.

78. The electrolyte of claim 77, wherein the electrolyte is a solid polymer electrolyte (SPE).

79. The electrolyte of claim 77, wherein the electrolyte is a gel electrolyte composition.

80. The electrolyte of any one of claims 77-79, wherein the concentration of the polymer in the electrolyte composition may be up to 50%, up to 10% by weight, or up to 5% by weight, or the concentration is 0.1-5% by weight, or 0.4-3% by weight, or 0.5-1.5% by weight.

81. The electrolyte of any one of claims 77-79, wherein the electrolyte composition further comprises a second polymer.

82. The electrolyte of claim 81, wherein the second polymer is selected from PEO-based polymers, polyvinylidene fluoride, carboxymethyl cellulose, polyvinyl acetate, and polyethylene glycol-based polymers.

83. An electrolyte comprising a separator and an electrolyte composition, wherein the electrolyte is an element of an electrochemical cell as defined in any one of claims 1-61.

84. The electrolyte of any one of claims 77-79, further comprising a lithium salt.

85. An electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode, the positive electrode, and the electrolyte comprises an element of an electrochemical cell as defined in any one of claims 1-61.

86. An electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein at least one of the negative electrode and the positive electrode comprises an electrode material as defined in any one of claims 62-76.

87. An electrochemical battery comprising a negative electrode, a positive electrode, and an electrolyte, wherein the electrolyte is as defined in any one of claims 77-83.

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