Electrochemical device having at least one gelled electrode

Abstract

The present invention relates to an electrochemical device, which comprises a) a positive electrode, b) a negative electrode, c) a separator and d) a liquid electrolyte, wherein at least one of the positive electrode and the negative electrode is a gelled electrode, the gelled electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, and wherein the d) liquid electrolyte comprises at least one organic carbonate and / or at least one ionic liquid, and at least one metal salt. The present invention also relates to a method for manufacturing an electrochemical device comprising at least one gelled electrode.

Description

[0001] Cross-reference to related applications

[0002] This application claims the priority of European Patent Application No. 20151214.2 filed on January 10, 2020, the entire content of which is incorporated herein by reference for all purposes. Technical field

[0003] The present invention relates to an electrochemical device comprising a) a positive electrode, b) a negative electrode, c) a separator and d) a liquid electrolyte, wherein at least one of the positive electrode and the negative electrode is a gelled electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, and wherein the d) liquid electrolyte comprises at least one organic carbonate and / or at least one ionic liquid, and at least one metal salt. The present invention also relates to a method for manufacturing an electrochemical device comprising at least one gelled electrode. Background art

[0004] For more than two decades, lithium batteries have maintained a dominant position in the market for rechargeable energy storage devices due to their many advantages including light weight, reasonable energy density, and good cycle life.

[0005] A liquid electrolyte is a substance that produces a conductive solution when dissolved in a polar solvent. The dissolved electrolyte dissociates into cations and anions, which are uniformly dispersed in the solvent. This solution is electrically neutral and is ion-conductive and electrically insulating.

[0006] Basic requirements for a suitable electrolyte for an electrochemical cell unit include high ionic conductivity, (electro)chemical stability, and safety. Conventional electrolytes are liquid and have played an important and dominant role in the field of electrochemical energy storage for decades due to their high ionic conductivity and good interface with electrodes. However, such liquid electrolytes pose safety problems due to their leakage and inherent explosive nature (e.g., combustion of organic solvents, generation of flammable volatile gaseous substances).

[0007] That is, Li-ion batteries have suffered from poor safety and relatively low energy density (relative to the energy density required for high-power applications such as electric vehicles (EVs), hybrid electric vehicles (HEVs), grid energy storage, etc.), and the root cause of such drawbacks is the presence of liquid electrolytes.

[0008] Therefore, safety is a prerequisite for batteries. Several protection mechanisms have been considered as measures to ensure battery safety. External protection relies on electronic devices such as temperature sensors and pressure vents, which ultimately increases the volume / weight of the battery and is unreliable under thermal / pressure abuse conditions. Internal protection schemes focus on using intrinsically safe materials for battery components and are thus considered a more suitable solution for battery safety.

[0009] Subsequently, hybrid organic / inorganic polymer composites with inorganic materials dispersed in organic polymers at the nanoscale or molecular level have attracted extensive scientific, technological, and industrial interest due to their unique properties. The hybridization of organic and inorganic compounds is an improved way to fabricate polymer structures (notably enhancing mechanical properties). In this regard, it is well known that the sol-gel method using metal alkoxides is the most useful and important method for preparing hybrid organic / inorganic polymer composites. In particular, in the presence of a preformed organic polymer (starting from fluoropolymers, especially vinylidene fluoride (VDF) polymers), the hydrolysis and condensation of metal alkoxides can be appropriately controlled to obtain hybrid organic / inorganic polymer composites with improved properties compared to the original organic and inorganic compounds. The polymer as an organic compound can improve the toughness and processability of the inorganic material, which is the metal alkoxide and is usually brittle, where the inorganic network can improve the scratch resistance, mechanical properties, and surface properties of the resulting hybrid organic / inorganic polymer composites.

[0010] In particular, WO 2015 / 169834 (SOLVAY SA and COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES) discloses a fluoropolymer hybrid organic / inorganic composite membrane obtainable by using sol-gel technology, which exhibits enhanced electrolyte retention ability and is suitable for use as a polymer electrolyte membrane in electrochemical devices. WO 2015 / 169835 (SOLVAY SA and COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES) further discloses a composite electrode that shows high adhesion to the metal current collector and high cohesion within the electroactive material while ensuring high ionic conductivity.

[0011] In addition, US 2018 / 0123167 (COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES) proposes a Li-ion battery that includes a positive electrode, a negative electrode, and an electrolyte containing a lithium salt, where all three of the positive electrode, negative electrode, and electrolyte are in the form of a gel.

[0012] Thus, for those skilled in the art, it is not obvious to combine at least one gelled electrode with a liquid electrolyte that requires the presence of a polymeric material as a standard separator to produce an electrochemical device.

[0013] The inventors of the present invention have unexpectedly demonstrated that the combination of at least one gelled electrode with a liquid electrolyte and a standard separator enables the production of a flexible / foldable electrochemical device that exhibits a high capacitance. The method according to the present invention also has the advantage of significantly reducing the time required to fill an assembled electrochemical device with a liquid electrolyte. SUMMARY OF THE INVENTION

[0014] A first object of the present invention is an electrochemical device comprising a) a positive electrode, b) a negative electrode, c) a separator, and d) a liquid electrolyte, wherein at least one of the positive electrode and the negative electrode is a gelled electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, and wherein the d) liquid electrolyte comprises at least one organic carbonate and / or at least one ionic liquid, and at least one metal salt.

[0015] A second object of the present invention is to provide a method for manufacturing an electrochemical device, the method comprising the following steps:

[0016] (I) At least assembling

[0017] a) A positive electrode;

[0018] b) A negative electrode; and

[0019] c) A separator disposed between the positive electrode and the negative electrode,

[0020] wherein at least one electrode is a gelled electrode obtained by the following method

[0021] - Providing an electronically conductive substrate;

[0022] - Providing a gelled electrode-forming composition

[0023] - Applying the gelled electrode-forming composition to the electronically conductive substrate;

[0024] - Optionally, drying the electronically conductive substrate coated with the gelled electrode-forming composition; and

[0025] - Calendering it into a film having a thickness between 80 μm and 900 μm, preferably between 100 μm and 800 μm, and more preferably between 200 μm and 600 μm, and

[0026] (II) Fill the assembled electrochemical device with a liquid medium (II) comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt.

[0027] In one aspect, the gelling electrode-forming composition according to the present invention comprises:

[0028] i) at least one partially fluorinated fluoropolymer, the at least one partially fluorinated fluoropolymer comprising

[0029] - at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer, and

[0030] - at least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group;

[0031] ii) at least one electroactive compound;

[0032] iii) a liquid medium (I);

[0033] iv) optionally, at least one conductive additive; and

[0034] v) optionally, at least one organic solvent (S) different from the liquid medium (I). BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A photograph of the prismatic cell unit of Example 1 is shown.

[0036] Figure 2 Photographs of the anode (a) and cathode (b) of the prismatic cell unit of Example 1 taken out from the assembly and unfolded are shown.

[0037] Figure 3 Photographs of the anode (a) and cathode (b) of the prismatic cell unit of Comparative Example 1 taken out from the assembly and unfolded are shown. DETAILED DESCRIPTION

[0038] Throughout this specification, unless the context otherwise requires, the word "comprise" or "include" or variations such as "comprises", "comprising", "includes", "including" shall be understood to mean including the stated element or method step or group of elements or method steps but not excluding any other element or method step or group of elements or method steps. According to a preferred embodiment, the words "comprise" and "include" and their variations mean "consisting of... only".

[0039] Unless the context clearly indicates otherwise, as used in this specification, the singular forms "a / an" and "the" include plural instances. The term "and / or" includes the meanings of "and", "or" and also includes all other possible combinations of the elements associated with that term.

[0040] The term "between" should be understood to include the limiting values.

[0041] As used herein, "alkyl" includes saturated hydrocarbons having one or more carbon atoms, including straight-chain alkyls such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl; cyclic alkyls (or "cycloalkyls" or "alicyclic" or "carbocyclic" groups), such as cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; branched-chain alkyls such as isopropyl, tert-butyl, sec-butyl and isobutyl; and alkyl-substituted alkyls, such as alkyl-substituted cycloalkyls and cycloalkyl-substituted alkyls.

[0042] As used herein, the term "(Cn-Cm)" with respect to an organic group, where n and m are integers respectively, means that the group can contain from n carbon atoms to m carbon atoms per group.

[0043] Ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It should be understood that this range format is used merely for convenience and brevity and should be interpreted flexibly as including not only the numerical values explicitly recited as the limits of the range, but also all individual numerical values or sub-ranges subsumed within that range, as if each numerical value and sub-range were explicitly recited. For example, a temperature range of about 120 °C to about 150 °C should be understood to include not only the explicitly recited limits of about 120 °C to about 150 °C, but also sub-ranges such as 125 °C to 145 °C, 130 °C to 150 °C, etc., and individual amounts within the specified range, including fractional amounts, such as 122.2 °C, 140.6 °C, and 141.3 °C.

[0044] Unless otherwise specified, in the context of the present invention, the amount of a component in a composition is expressed as the ratio between the weight of the component and the total weight of the composition multiplied by 100 (i.e., weight % or wt%).

[0045] The term "electrochemical device" is herein intended to mean an electrochemical cell unit / component including a positive electrode, a negative electrode, and a liquid electrolyte, wherein a single-layer or multi-layer separator is brought into contact with at least one surface of one of the electrodes. Non-limiting examples of suitable electrochemical devices notably include secondary batteries, especially alkali metal or alkaline earth metal secondary batteries (such as lithium-ion batteries, lead-acid batteries), and capacitors, especially lithium-ion-based capacitors and double-layer capacitors (supercapacitors).

[0046] The components of the electrochemical device according to the present invention are described in detail below. It should be understood that the foregoing general description and the following detailed description are both exemplary and intended to provide further explanation of the claimed invention. Accordingly, various changes and modifications described herein will be apparent to those skilled in the art. In addition, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

[0047] The present invention provides an electrochemical device comprising a) a positive electrode, b) a negative electrode, c) a separator, and d) a liquid electrolyte, wherein at least one of the positive electrode and the negative electrode is a gelled electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, and wherein the d) liquid electrolyte comprises at least one organic carbonate and / or at least one ionic liquid, and at least one metal salt.

[0048] According to the present invention, the combination of at least one of a) the positive electrode and b) the negative electrode in gel form with the liquid electrolyte and a standard separator enables the production of a flexible / foldable electrochemical device with a high-loading electrode having an areal capacity between 1.0 mAh / cm 2 and 9.0 mAh / cm 2 and preferably between 4.0 mAh / cm 2 and 7.0 mAh / cm 2 The gelled electrode exhibits higher flexibility than a conventional electrode and, notably, has a higher loading of electroactive material without damage to the electrode structure.

[0049] Furthermore, considering the manufacturing method, the filling time of the electrochemical device can be significantly reduced once it is assembled with the liquid electrolyte.

[0050] In the present invention, the term "negative electrode" is specifically intended to denote the electrode of an electrochemical cell unit in which oxidation occurs during discharge.

[0051] In the present invention, the term "positive electrode" is specifically intended to denote the electrode of an electrochemical cell unit in which reduction occurs during discharge.

[0052] For the purposes of the present invention, the term "gelled electrode" is defined as follows.

[0053] In an embodiment, at least one of the positive electrode and the negative electrode according to the present invention has a thickness between 80 μm and 900 μm, preferably between 100 μm and 800 μm, and more preferably between 200 μm and 600 μm.

[0054] Thus, the gelled electrodes used in the electrochemical devices of the present invention can have a rather high thickness, which allows for a high loading of the electrodes while maintaining a uniform distribution of the active material, the partially fluorinated fluoropolymer, and the conductive substrate. Consequently, the resulting devices have a high capacity and are capable of delivering high energy.

[0055] In the present invention, the term "filling time" is hereby defined as the time required to inject the liquid medium and ensure its proper distribution within the electrochemical device to fully wet the electrodes and the separator.

[0056] In the present invention, the nature of the electronically conductive substrate depends on whether the electrode provided thereby is a positive electrode or a negative electrode. If the electrode of the present invention is a positive electrode, the electronically conductive substrate typically comprises, preferably consists of, carbon (C) or at least one metal selected from the group consisting of aluminum (Al), nickel (Ni), titanium (Ti), and their alloys, preferably Al. If the electrode of the present invention is a negative electrode, the electronically conductive substrate typically comprises, preferably consists of, carbon (C) or silicon (Si) or at least one metal selected from the group consisting of lithium (Li), sodium (Na), zinc (Zn), magnesium (Mg), copper (Cu), and their alloys, preferably Cu.

[0057] The term "separator" is hereby intended to denote a single-layer or multi-layer polymer or ceramic material / membrane that electrically and physically separates electrodes of opposite polarities in an electrochemical device and is permeable to ions flowing therebetween.

[0058] In the present invention, the separator can be any porous substrate commonly used as a separator in electrochemical devices.

[0059] In one embodiment, the separator is a porous polymer material comprising at least one material selected from the group consisting of polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyphenylene sulfide, polyacetal, polyamide, polycarbonate, polyimide, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyvinylnaphthalene, poly(ethylene oxide), polyacrylonitrile, polyolefins such as polyethylene and polypropylene, or mixtures thereof.

[0060] In a specific embodiment, the separator is a porous polymer material coated with PVDF or inorganic nanoparticles (e.g., SiO 2 , TiO 2 , Al 2 O 3 , ZrO 2 , etc.).

[0061] In the present invention, the term "liquid medium" is intended to denote a medium containing one or more substances that is in a liquid state at 20 °C under atmospheric pressure. In the present invention, the term "liquid medium (I)" is intended to denote the liquid medium contained within the gelled electrode-forming composition.

[0062] In the present invention, the term "liquid medium (II)" is intended to denote the liquid medium added during the filling stage. The liquid medium (II) then exists and is distributed throughout the electrochemical device.

[0063] In the present invention, the term "liquid medium" is intended to correspond to either liquid medium (I) or liquid medium (II).

[0064] In the present invention, the liquid electrode contains a mixture of liquid medium (I) and liquid medium (II).

[0065] In the present invention, liquid medium (I) and liquid medium (II) are the same or different.

[0066] In the present invention, liquid medium (I) and liquid medium (II) each contain at least one organic carbonate and / or at least one ionic liquid.

[0067] In the present invention, at least one of liquid medium (I) and liquid medium (II) additionally contains at least one metal salt.

[0068] In one embodiment, a separator and a liquid medium (II) containing at least one organic carbonate and / or at least one ionic liquid are placed between a) the positive electrode and b) the negative electrode.

[0069] In the present invention, the choice of organic carbonate or ionic liquid is not particularly limited, provided that it is suitable for dissolving the metal salt.

[0070] In one embodiment, the metal salt is selected from the group consisting of:

[0071] (a) MeI, Me(PF 6 ) n , Me(BF 4 ) n , Me(ClO 4 ) n , Me(bis(oxalato)borate)n (“Me(BOB) n ”), MeCF 3 SO 3 , Me[N(SO 2 F) 2 n , Me[N(CF 3 SO 2 ) 2 n ​​, Me[N(C 2 F 5 SO 2 ) 2 n , Me[N(CF 3 SO 2 )(R F SO 2 )] n (wherein R F is C 2 F 5 , C 4 F 9 or CF 3 OCF 2 CF 2 ), Me(AsF 6 ) n , Me[C(CF 3 SO 2 ) 3 n , Me 2 S n , where Me is a metal, preferably a transition metal, an alkali metal or an alkaline earth metal, more preferably Me is Li, Na, K or Cs, even more preferably Me is Li, and n is the valence of the metal, typically n is 1 or 2;

[0072] (b)

[0073] wherein R’ F is selected from the group consisting of: F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 2 F 5 , C 3 H 4 F 3 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F​​5 , C 5 F 11 , C 3 F 5 OCF 3 , C 2 F 4 OCF 3 , C 2 H 2 F 2 OCF 3 and CF 2 OCF 3 ; and

[0074] (c) their combinations.

[0075] In one embodiment, the organic carbonate is a partially or fully fluorinated carbonate compound. The organic carbonate compound according to the present invention can be a cyclic carbonate or an acyclic carbonate.

[0076] Non-limiting examples of the organic carbonate compound notably include ethylene carbonate (1,3-dioxolan-2-one), propylene carbonate, vinylene carbonate (1,3-dioxolene-2-one), 4-methylene-1,3-dioxolan-2-one, 4,5-dimethylene-1,3-dioxolan-2-one, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dipropyl carbonate, methyl propyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, propyl butyl carbonate, dibutyl carbonate, di-tert-butyl carbonate, and butylene carbonate.

[0077] The fluorinated carbonate compound can be monofluorinated or polyfluorinated. Suitable examples of the fluorinated carbonate compound include, but are not limited to, monofluorinated ethylene carbonate (4-fluoro-1,3-dioxolan-2-one) and difluorinated ethylene carbonate, monofluorinated and difluorinated propylene carbonate, monofluorinated and difluorinated butylene carbonate, 3,3,3-trifluoropropylene carbonate, fluorinated dimethyl carbonate, fluorinated diethyl carbonate, fluorinated methyl ethyl carbonate, fluorinated dipropyl carbonate, fluorinated dibutyl carbonate, fluorinated methyl propyl carbonate, and fluorinated ethyl propyl carbonate.

[0078] In a preferred embodiment, the selected organic carbonate is a mixture of ethylene carbonate and propylene carbonate.

[0079] In another preferred embodiment, the selected organic carbonate is a mixture of ethylene carbonate, propylene carbonate, and vinylene carbonate.

[0080] In another embodiment, in addition to the organic carbonate, the liquid medium further comprises at least one sulfone compound. The sulfone compound according to the present invention can be a cyclic sulfone or an acyclic sulfone.

[0081] Non-limiting examples of sulfone compounds notably include tetramethylene sulfone (sulfolane), butadiene sulfone / sulfolene, pentamethylene sulfone, hexamethylene sulfone, thiazolidine 1,1-dioxide, thiomorpholine 1,1-dioxide, dimethyl sulfone, diethyl sulfone, ethyl methyl sulfone, and mixtures thereof.

[0082] In a preferred embodiment, the liquid medium comprises a mixture of ethylene carbonate, propylene carbonate, vinylene carbonate, and sulfolane.

[0083] In a preferred embodiment, the liquid medium (II) is a mixture of organic carbonate compounds that can best wet the separator. In a more preferred embodiment, the mixture of organic carbonate compounds includes cyclic carbonates and / or acyclic carbonates. Non-limiting examples of organic carbonate compounds notably include ethylene carbonate (1,3-dioxolan-2-one), propylene carbonate, vinylene carbonate (1,3-dioxolene-2-one), 4-methyl-1,3-dioxolan-2-one, 4,5-dimethyl-1,3-dioxolan-2-one, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methyl propyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, propyl butyl carbonate, dibutyl carbonate, di-tert-butyl carbonate, and butylene carbonate.

[0084] As used herein, the term "ionic liquid" refers to a compound comprising a positively charged cation and a negatively charged anion, which is liquid at a temperature of 100 °C or lower at atmospheric pressure. While ordinary liquids such as water are mainly composed of electrically neutral molecules, ionic liquids are mainly composed of ions and short-lived ion pairs. As used herein, the term "ionic liquid" refers to a compound without a solvent.

[0085] As used herein, the term "cationic atom" refers to at least one non-metal atom with a positive charge.

[0086] As used herein, the term "onium cation" refers to a positively charged ion, at least a part of the charge of which is located on at least one non-metal atom such as O, N, S, or P.

[0087] In the present invention, the ionic liquid has the general formula A n- Q l+ (n / l) , wherein,

[0088] -A n- represents an anion;

[0089] -Q l+ (n / l) represents a cation;

[0090] -n and l are independently selected between 1 and 5 and represent the anions A n- and the cations Q l+ (n / l) charge, respectively.

[0091] One or more cations can be independently selected from metal cations and organic cations. One or more cations can be monovalent cations or polyvalent cations.

[0092] As metal cations, mention may preferably be made of alkali metal cations, alkaline earth metal cations and cations of d-block elements.

[0093] In the present invention, Q l+ (n / l) can represent an onium cation. An onium cation is a cation formed by an element of Group VB or VIB (as defined by the old European IUPAC system of the Periodic Table of the Elements) with three or four hydrocarbon chains. Group VB includes N, P, As, Sb and Bi atoms. Group VIB includes O, S, Se, Te and Po atoms. The onium cation can in particular be a cation formed by an atom selected from the group consisting of N, P, O and S (more preferably N and P) with three or four hydrocarbon chains.

[0094] The onium cation Q l+ (n / l) can be selected from:

[0095] - heterocyclic onium cations; in particular those selected from the group consisting of:

[0096]

[0097] - unsaturated cyclic onium cations; in particular those selected from the group consisting of:

[0098]

[0099] - saturated cyclic onium cations; in particular those selected from the group consisting of:

[0100]

[0101] and

[0102] - acyclic onium cations; in particular those having the general formula + L-R’ s wherein L represents an atom selected from the group consisting of N, P, O and S, more preferably N and P, s represents the number of R’ groups selected from 2, 3 or 4 according to the valence of the element L, and each R’ independently represents a hydrogen atom or C 1 to C 8alkyl, and at L + The bond between R’ can be a single bond or a double bond.

[0103] In the above formula, each “R” symbol independently represents a hydrogen atom or an organic group. Preferably, in the above formula, each “R” symbol can independently represent a hydrogen atom, or a saturated or unsaturated, straight-chain, branched-chain or cyclic C 1 to C 18 hydrocarbyl group which is optionally substituted one or more times by a halogen atom, an amino group, an imino group, an amido group, an ether group, an ester group, a hydroxyl group, a carboxyl group, a carbamoyl group, a cyano group, a sulfone group or a sulfite group.

[0104] The cation Q l+ (n / l) can more particularly be selected from the cations of ammonium, phosphonium, pyridinium, pyrrolidinium, pyrazolinium, imidazolium, arsonium, quaternary phosphonium and quaternary ammonium.

[0105] The quaternary phosphonium cation or quaternary ammonium cation can more preferably be selected from a tetraalkylammonium cation or a tetraalkylphosphonium cation, a trialkylbenzylammonium cation or a trialkylbenzylphosphonium cation or a tetraarylammonium cation or a tetraarylphosphonium cation, wherein the alkyl group (identical or different) represents a straight-chain or branched-chain alkyl chain having from 4 to 12 carbon atoms, preferably from 4 to 6 carbon atoms, and wherein the aryl group (identical or different) represents a phenyl group or a naphthyl group.

[0106] In a particular embodiment, Q l+ (n / l) represents a quaternary phosphonium cation or a quaternary ammonium cation.

[0107] In a preferred embodiment, Q l+ (n / l) represents a quaternary phosphonium cation. Non-limiting examples of quaternary phosphonium cations include trihexyl(tetradecyl)phosphonium and tetraalkylphosphonium cations, in particular tetrabutylphosphonium (PBu 4 ) cation.

[0108] In another embodiment, Q l+ (n / l) represents an imidazolium cation. Non-limiting examples of imidazolium cations include 1,3-dimethylimidazolium, 1-(4-sulfobutyl)-3-methylimidazolium, 1-allyl-3H-imidazolium, 1-butyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-octyl-3-methylimidazolium.

[0109] In another embodiment, Q l+ (n / l)represents a quaternary ammonium cation, which is particularly selected from the group consisting of: tetraethylammonium, tetrapropylammonium, tetrabutylammonium, trimethylbenzylammonium, methyltributylammonium, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium, N,N-dimethyl-N-ethyl-N-(3-methoxypropyl)ammonium, N,N-dimethyl-N-ethyl-N-benzylammonium, N,N-dimethyl-N-ethyl-N-phenethylammonium, N-tributyl-N-methylammonium, N-trimethyl-N-butylammonium, N-trimethyl-N-hexylammonium, N-trimethyl-N-propylammonium, and Aliquat 336 (a mixture of methyltri(C 8 to C 10 alkyl)ammonium compounds).

[0110] In one embodiment, Q l+ (n / l) represents a piperidinium cation, in particular N-butyl-N-methylpiperidinium, N-propyl-N-methylpiperidinium.

[0111] In another embodiment, Q l+ (n / l) represents a pyridinium cation, in particular N-methylpyridinium.

[0112] In a more preferred embodiment, Q l+ (n / l) represents a pyrrolidinium cation. Among specific pyrrolidinium cations, the following may be mentioned: C 1-12 alkyl-C 1-12 alkyl-pyrrolidinium, and more preferably C 1-4 alkyl-C 1-4 alkyl-pyrrolidinium. Examples of pyrrolidinium cations include, but are not limited to, N,N-dimethylpyrrolidinium, N-ethyl-N-methylpyrrolidinium, N-isopropyl-N-methylpyrrolidinium, N-methyl-N-propylpyrrolidinium, N-butyl-N-methylpyrrolidinium, N-octyl-N-methylpyrrolidinium, N-benzyl-N-methylpyrrolidinium, N-cyclohexylmethyl-N-methylpyrrolidinium, N-[(2-hydroxy)ethyl]-N-methylpyrrolidinium. More preferred are N-methyl-N-propylpyrrolidinium (PYR13) and N-butyl-N-methylpyrrolidinium (PYR14).

[0113] Non-limiting examples of the anions of the ionic liquid include iodide, bromide, chloride, hydrogensulfate, dicyanamide ion, acetate, diethylphosphate, methylphosphonate, fluoride anions (such as hexafluorophosphate (PF 6 - )) and tetrafluoroborate (BF 4 - ))), and oxaloborate having the following formula:

[0114]

[0115] In one embodiment, A n- is a fluorinated anion. Among the fluorinated anions that can be used in the present invention, the fluorinated sulfonylimide anion can be particularly advantageous. The organic anion can be particularly selected from anions having the following general formula:

[0116] (E a -SO 2 )N - R

[0117] wherein:

[0118] -E a represents a fluorine atom or preferably a group having from 1 to 10 carbon atoms, the group being selected from fluoroalkyl, perfluoroalkyl and fluoroalkenyl, and

[0119] -R represents a substituent.

[0120] Preferably, E a can represent F or CF 3 .

[0121] According to the first embodiment, R represents a hydrogen atom.

[0122] According to the second embodiment, R represents a straight-chain or branched-chain, cyclic or acyclic hydrocarbon-based group preferably having from 1 to 10 carbon atoms, the group optionally having one or more degrees of unsaturation, and the group optionally being substituted one or more times with a halogen atom, a nitrile functional group; or an alkyl group optionally substituted one or more times with a halogen atom. In addition, R can represent a nitrile group -CN.

[0123] According to the third embodiment, R represents a sulfonate group. In particular, R can represent the group -SO 2 -E a , E a being as defined above. In this case, the fluorinated anion can be symmetric, i.e., such that the two E a groups of the anion are the same, or asymmetric, i.e., such that the two E a groups of the anion are different.

[0124] In addition, R can represent the group -SO 2-R’, where R’ represents a linear or branched, cyclic or acyclic hydrocarbon-based group preferably having from 1 to 10 carbon atoms, which group is optionally provided with one or more degrees of unsaturation and which group is optionally substituted one or more times by a halogen atom, a nitrile functional group; or an alkyl group optionally substituted one or more times by a halogen atom. In particular, R’ may comprise a vinyl or allyl group. Additionally, R may represent the group -SO 2 -N-R’, where R’ is as defined above or alternatively R’ represents a sulfonate functional group -SO 3 .

[0125] The hydrocarbon-based cyclic group may preferably refer to a cycloalkyl or aryl group. “Cycloalkyl” refers to a monocyclic hydrocarbon chain having 3 to 8 carbon atoms. Preferred examples of cycloalkyl are cyclopentyl and cyclohexyl. “Aryl” refers to a monocyclic or polycyclic aromatic hydrocarbon group having 6 to 20 carbon atoms. Preferred examples of aryl are phenyl and naphthyl. When the group is a polycyclic group, the rings may be fused or linked by a σ (sigma) bond.

[0126] According to the fourth embodiment, R represents a carbonyl group. R may in particular be represented by the formula -CO-R’, where R’ is as defined above.

[0127] The organic anions that can be used in the present invention may advantageously be selected from the group consisting of: CF 3 SO 2 N - SO 2 CF 3 (bis(trifluoromethanesulfonyl)imide anion, usually denoted as TFSI), FSO 2 N - SO 2 F (bis(fluorosulfonyl)imide anion, usually denoted as FSI), CF 3 SO 2 N - SO 2 F and CF 3 SO 2 N - SO 2 N - SO 2 CF 3 .

[0128] In a preferred embodiment, the ionic liquid contains:

[0129] - a positively charged cation selected from the group consisting of imidazolium ions, pyridinium ions, pyrrolidinium ions and piperidinium ions, optionally containing one or more C 1 -C 30 alkyl groups, and

[0130] - A negatively charged anion selected from the group consisting of: halide ions, fluorinated anions, and borate anions.

[0131] C 1 -C 30 Non-limiting examples of alkyl groups notably include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, 2,2-dimethyl-propyl, hexyl, 2,3-dimethyl-2-butyl, heptyl, 2,2-dimethyl-3-pentyl, 2-methyl-2-hexyl, octyl, 4-methyl-3-heptyl, nonyl, decyl, undecyl, and dodecyl.

[0132] In one embodiment, the gelled electrode comprises an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, the gelled electrode-forming composition comprising:

[0133] i) At least one partially fluorinated fluoropolymer comprising

[0134] - At least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer, and

[0135] - At least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group;

[0136] ii) At least one electroactive compound;

[0137] iii) A liquid medium (I) comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt;

[0138] iv) Optionally, at least one conductive additive; and

[0139] v) Optionally, at least one organic solvent (S) different from the liquid medium (I).

[0140] For the purposes of the present invention, the term "electroactive compound" is intended to mean a compound that is capable of binding or inserting alkali metal or alkaline earth metal ions into its structure and substantially releasing alkali metal or alkaline earth metal ions during the charging and discharging phases of an electrochemical device. The electroactive compound preferably is capable of binding or inserting and releasing lithium ions.

[0141] The nature of the electroactive compound depends on whether the electrode provided thereby is a positive electrode or a negative electrode.

[0142] In the case of forming a positive electrode for a Li-ion secondary battery, the electroactive compound is not particularly limited. The electroactive compound may include those having the formula LiMQ 2Composite metal chalcogenides, where M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr, and V, and Q is a chalcogen element such as O or S. Among these, it is preferable to use those having the formula LiMO 2 Based lithium composite metal oxides, where M is as defined above. Preferred examples thereof may include LiCoO 2 , LiNiO 2 , LiNi x Co 1-x O 2 (0 < x < 1) and spinel-structured LiMn 2 O 4 . Another preferred example thereof may include metal oxides based on lithium-nickel-manganese-cobalt having the formula LiNi x Mn y Co z O 2 (x + y + z = 1, referred to as NMC), such as LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 , LiNi 0.6 Mn 0.2 Co 0.2 O 2 , and metal oxides based on lithium-nickel-cobalt-aluminum having the formula LiNi x Co y Al z O 2 (x + y + z = 1, referred to as NCA), such as LiNi 0.8 Co 0.15 Al 0.05 O 2 .

[0143] As an alternative, still in the case of forming the positive electrode for a Li-ion secondary battery, the electroactive compound may include electroactive materials based on lithiated or partially lithiated transition metal oxyanions having the formula M 1 M 2 (JO 4 ) f E 1-f , where M 1 is lithium, which may be partially replaced by another alkali metal that occupies less than 20% of M 1 metal; M 2 is a transition metal selected from Fe, Mn, Ni, or a mixture thereof at an oxidation level of +2, which may be partially replaced by one or more additional metals that are at an oxidation level between +1 and +5 and occupy M 2Less than 35% of metal, including 0; JO 4 is any oxygen anion, where J is P, S, V, Si, Nb, Mo or a combination thereof; E is a fluoride anion, a hydroxide anion or a chloride anion; f is JO 4 The mole fraction of the oxygen anion, generally included between 0.75 and 1.

[0144] M as defined above 1 M 2 (JO 4 ) f E 1-f The electroactive material is preferably phosphate-based and may have an ordered or modified olivine structure.

[0145] More preferably, the electroactive compound has the formula Li 3-x M’ y M” 2-y (JO 4 ) 3 , where 0 ≤ x ≤ 3, 0 ≤ y ≤ 2; M' and M” are the same or different metals, at least one of which is a transition metal; JO 4 is preferably PO 4 , which may be partially replaced by another oxygen anion, where J is either S, V, Si, Nb, Mo or a combination thereof. Even more preferably, the electroactive compound is a phosphate-based electroactive material having the formula Li(Fe x Mn 1-x )PO 4 , where 0 ≤ x ≤ 1, where x is preferably 1 (i.e., lithium iron phosphate having the formula LiFePO 4 ).

[0146] In the case of forming the negative electrode for a lithium secondary battery, the electroactive compound may preferably comprise:

[0147] - Graphite carbon capable of embedding lithium, typically present in the form of lithium-bearing powder, flakes, fibers, or spheres (e.g., mesophase carbon microbeads);

[0148] - Lithium metal;

[0149] - Lithium alloy compositions, notably including those described in US 6203944 (3M Innovative Properties Co.);

[0150] - Lithium titanate, generally having the formula Li 4 Ti 5 O 12It is shown that these compounds are generally considered to be "zero-strain" insertion materials, which have a low level of physical expansion when absorbing mobile ions (i.e., Li + ).

[0151] - Lithium-silicon alloys, commonly known as lithium silicides with a high Li / Si ratio, especially lithium silicide having the formula Li 4.4 Si;

[0152] - Composite materials based on carbonaceous materials having silicon and / or silicon oxide, notably graphite carbon / silicon and graphite / silicon oxide, wherein the graphite carbon is composed of one or several carbons capable of inserting lithium;

[0153] - Lithium-germanium alloys, including a crystalline phase having the formula Li 4.4 Ge.

[0154] In a preferred embodiment, the electroactive compound for the positive electrode is LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 , LiNi 0.6 Mn 0.2 Co 0.2 O 2 or LiNi 0.8 Co 0.15 Al 0.05 O 2 .

[0155] In another preferred embodiment, the electroactive compound for the negative electrode is graphite carbon or graphite carbon / silicon.

[0156] In one embodiment, at least one electroactive compound according to the present invention is loaded onto the electronically conductive substrate to have a surface capacity between 1.0 mAh / cm 2 and 9.0 mAh / cm 2 , preferably between 4.0 mAh / cm 2 and 7.0 mAh / cm 2 .

[0157] In a preferred embodiment, the electrochemical device according to the present invention includes a gelled positive electrode and lithium metal as the negative electrode.

[0158] In another preferred embodiment, the electrochemical device according to the present invention includes a gelled positive electrode and a gelled negative electrode.

[0159] For the purposes of the present invention, the term "partially fluorinated fluoropolymer" is intended to denote a polymer comprising at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer and at least one second repeating unit derived from at least one hydrogenated monomer, wherein at least one of the ethylenically unsaturated fluorinated monomer and the hydrogenated monomer comprises at least one hydrogen atom.

[0160] The term "fluorinated monomer" is herein intended to denote an ethylenically unsaturated monomer comprising at least one fluorine atom.

[0161] The term "hydrogenated monomer" is herein intended to denote an ethylenically unsaturated monomer comprising at least one hydrogen atom and no fluorine atoms.

[0162] The term "at least one fluorinated monomer" is to be understood to mean that the partially fluorinated fluoropolymer may comprise repeating units derived from one or more than one fluorinated monomer. In the present invention, the expression "fluorinated monomer" is to be understood, for the purposes of the present invention, to be both plural and singular in form, i.e. they denote one or more than one fluorinated monomer as defined above.

[0163] The term "at least one hydrogenated monomer" is to be understood to mean that the polymer may comprise repeating units derived from one or more than one hydrogenated monomer. In the present invention, the expression "hydrogenated monomer" is to be understood, for the purposes of the present invention, to be both plural and singular in form, i.e. they denote one or more than one hydrogenated monomer as defined above.

[0164] Partially fluorinated fluoropolymers typically comprise at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer, at least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group, and optionally a third repeating unit derived from at least one fluorinated monomer different from the first repeating unit.

[0165] Partially fluorinated fluoropolymers can typically be obtained by polymerizing: at least one fluorinated monomer, at least one hydrogenated monomer comprising at least one carboxyl group, and optionally at least one fluorinated monomer different from the fluorinated monomer.

[0166] If the fluorinated monomer comprises at least one hydrogen atom, it is designated as a hydrogen-containing fluorinated monomer.

[0167] If the fluorinated monomer contains no hydrogen atoms, it is designated as a per(halo)fluorinated monomer.

[0168] The fluorinated monomer may further comprise one or more other halogen atoms (Cl, Br, I).

[0169] Non-limiting examples of suitable fluorinated monomers notably include the following:

[0170] -C2 -C 8 Perfluoroolefins, such as tetrafluoroethylene and hexafluoropropylene;

[0171] -C 2 -C 8 Hydrogenated fluoroolefins, such as vinylidene fluoride, vinyl fluoride, 1,2-difluoroethylene and trifluoroethylene;

[0172] - Perfluoroalkyl vinyls having the formula CH 2 =CH-R f0 wherein R f0 is C 1 -C 6 perfluoroalkyl;

[0173] - Chloro - and / or bromo - and / or iodo - C 2 -C 6 fluoroolefins, such as chlorotrifluoroethylene;

[0174] - (Per)fluoroalkyl vinyl ethers having the formula CF 2 =CFOR f1 wherein R f1 is C 1 -C 6 fluoroalkyl or perfluoroalkyl, for example CF 3 、C 2 F 5 、C 3 F 7 ;

[0175] -CF 2 =CFOX 0 (Per)fluoro - oxyalkyl vinyl ethers, wherein X 0 is C 1 -C 12 alkyl, C 1 -C 12 oxyalkyl or C 1 -C 12 (per)fluorooxyalkyl having one or more ether groups, such as perfluoro - 2 - propoxy - propyl;

[0176] - (Per)fluoroalkyl vinyl ethers having the formula CF 2 =CFOCF 2 OR f2 wherein R f2 is C 1 -C 6 fluoroalkyl or perfluoroalkyl, for example CF 3 、C 2 F 5 、C 3 F 7 ,or C having one or more ether groups1 -C 6 (per)fluorooxyalkyl group such as -C 2 F 5 -O-CF 3 ;

[0177] - a functional (per)fluoro-oxyalkyl vinyl ether having the formula CF 2 =CFOY 0 wherein Y 0 is C 1 -C 12 alkyl or (per)fluoroalkyl, C 1 -C 12 oxyalkyl or C having one or more ether groups 1 -C 12 (per)fluorooxyalkyl group, and Y 0 contains a carboxylic acid or sulfonic acid group in the form of its acid, acyl halide or salt; and

[0178] - fluorometa-dioxolene, preferably perfluorometa-dioxolene.

[0179] If the fluorinated monomer is a hydrogen-containing fluorinated monomer such as vinylidene fluoride, trifluoroethylene or fluoroethylene, the partially fluorinated fluoropolymer is a partially fluorinated fluoropolymer comprising repeating units derived from: at least one hydrogen-containing fluorinated monomer, at least one hydrogenated monomer comprising at least one carboxyl group, and optionally at least one fluorinated monomer different from the hydrogen-containing fluorinated monomer.

[0180] If the fluorinated monomer is a fully (halo)fluorinated monomer such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene or perfluoroalkyl vinyl ether, the partially fluorinated fluoropolymer is a partially fluorinated fluoropolymer comprising repeating units derived from: at least one fully (halo)fluorinated monomer, at least one hydrogenated monomer comprising at least one carboxyl group, and optionally at least one fluorinated monomer different from the fully (halo)fluorinated monomer.

[0181] The partially fluorinated fluoropolymer can be amorphous or semi-crystalline.

[0182] The term "amorphous" is intended herein to mean a polymer having a heat of fusion of less than 5 J / g, preferably less than 3 J / g, more preferably less than 2 J / g as measured according to ASTM D3418-08.

[0183] The term "semi-crystalline" is intended herein to mean a polymer having a heat of fusion of from 10 to 90 J / g, preferably from 30 to 60 J / g, more preferably from 35 to 55 J / g as measured according to ASTM D3418-08.

[0184] The partially fluorinated fluoropolymer is preferably semi-crystalline.

[0185] The partially fluorinated fluoropolymer contains at least one second repeating unit derived from at least one hydrogenated monomer containing at least one carboxyl group, preferably at least 0.01 mol%, more preferably at least 0.05 mol%, and even more preferably at least 0.1 mol%.

[0186] The partially fluorinated fluoropolymer contains at least one second repeating unit derived from at least one hydrogenated monomer containing at least one carboxyl group, preferably at most 20 mol%, more preferably at most 15 mol%, even more preferably at most 10 mol%, and most preferably at most 3 mol%.

[0187] The determination of the average molar percentage of at least one second repeating unit derived from at least one hydrogenated monomer containing at least one carboxyl group in the partially fluorinated fluoropolymer can be carried out by any suitable method. The acid-base titration method or the NMR method may be notably mentioned.

[0188] The partially fluorinated fluoropolymer is preferably a partially fluorinated fluoropolymer containing repeating units derived from vinylidene fluoride (VDF), at least one hydrogenated monomer containing at least one carboxyl group, and optionally at least one fluorinated monomer different from VDF.

[0189] In a preferred embodiment, the partially fluorinated fluoropolymer preferably contains repeating units derived from:

[0190] - vinylidene fluoride (VDF) in an amount of at least 60 mol%, preferably at least 75 mol%, and more preferably at least 85 mol%,

[0191] - at least one hydrogenated monomer containing at least one carboxyl group in an amount of from 0.01 mol% to 20 mol%, preferably from 0.05 mol% to 15 mol%, and more preferably from 0.1 mol% to 10 mol%, and

[0192] - optionally, at least one fluorinated monomer in an amount of from 0.1 mol% to 15 mol%, preferably from 0.1 mol% to 12 mol%, and more preferably from 0.1 mol% to 10 mol%, the at least one fluorinated monomer being selected from vinyl fluoride, chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), trifluoroethylene, and perfluoromethyl vinyl ether (PMVE).

[0193] In another preferred embodiment, based on the total weight of the liquid medium (I) in the gelation electrode-forming composition of the present invention, the amount of the partially fluorinated fluoropolymer is from 3.0 to 50.0 wt%, preferably from 5.0 to 40 wt%, and more preferably from 7.0 to 35.0 wt%.

[0194] In one embodiment, the intrinsic viscosity of the partially fluorinated fluoropolymer is less than 0.70 l / g, preferably less than 0.60 l / g, and more preferably less than 0.50 l / g.

[0195] In another embodiment, the intrinsic viscosity of the partially fluorinated fluoropolymer is greater than 0.15 l / g, preferably greater than 0.20 l / g, and more preferably greater than 0.25 l / g.

[0196] In the present invention, the intrinsic viscosity is measured at 25 °C using an Ubbelohde viscometer, based on the falling time of a solution obtained by dissolving the polymer in N,N-dimethylformamide at a concentration of about 0.2 g / dl, using the following equation at 25 °C.

[0197]

[0198] where c is the polymer concentration [g / l], η r is the relative viscosity, i.e., the ratio between the falling time of the sample solution and the falling time of the solvent, η sp is the specific viscosity, i.e., η r -1, and Γ is the experimental factor, which corresponds to 3 for the polymer.

[0199] The hydrogenated monomer containing at least one carboxyl group is preferably selected from the group consisting of (meth)acrylic monomers having the formula (I):

[0200]

[0201] where R 1 , R 2 and R 3 are each the same or different from one another and independently are a hydrogen atom or a C 1 -C 3 hydrocarbyl group.

[0202] Non-limiting examples of the hydrogenated monomer containing at least one carboxyl group notably include acrylic acid and methacrylic acid.

[0203] The partially fluorinated fluoropolymer is advantageously a linear polymer in a linear sequence comprising: a first repeating unit derived from at least one fluorinated monomer, a second repeating unit derived from at least one hydrogenated monomer containing at least one carboxyl group, and optionally a third repeating unit derived from at least one fluorinated monomer different from the first repeating unit.

[0204] Thus, the partially fluorinated fluoropolymer is typically distinguishable from a graft polymer.

[0205] The partially fluorinated fluoropolymer is advantageously a random polymer comprising a linear sequence of randomly distributed repeating units, i.e., a first repeating unit derived from at least one fluorinated monomer, a second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group, and optionally a third repeating unit derived from at least one fluorinated monomer different from the first repeating unit.

[0206] The expression "randomly distributed repeating units" is intended to represent the percentage ratio between the average number of sequences (%) of at least one hydrogenated monomer (the sequences being included between two repeating units derived from at least one fluorinated monomer) and the total average number (%) of repeating units derived from at least one hydrogenated monomer.

[0207] When each of the repeating units derived from at least one hydrogenated monomer is separate, i.e., the repeating units derived from the hydrogenated monomer are included between two repeating units of at least one fluorinated monomer, the average number of sequences of at least one hydrogenated monomer is equal to the total average number of repeating units derived from at least one hydrogenated monomer, such that the fraction of randomly distributed repeating units derived from at least one functional hydrogenated monomer is 100%: this value corresponds to a complete random distribution of the repeating units derived from at least one hydrogenated monomer. Thus, the greater the number of separate repeating units derived from at least one hydrogenated monomer relative to the total number of repeating units derived from at least one functional hydrogenated monomer, the higher the percentage fraction value of the randomly distributed repeating units derived from at least one hydrogenated monomer will be.

[0208] Thus, the partially fluorinated fluoropolymer is typically distinguishable from a block polymer.

[0209] In the present invention, the term "conductive additive" is intended to denote a material for ensuring that the electrode has good charge and discharge performance. Non-limiting examples of suitable conductive additives include carbon black, acetylene black, carbon fiber, carbon nanotubes, and Ketjen black. Suitable conductive carbon includes acetylene black. A commercially available carbon black is Super available from Alfa Aesar Depending on the characteristics of the conductive additive, the conductive additive is preferably present in an amount of 1 to 10 wt% based on the total weight of the electrode-forming composition. The conductive additive is more preferably present in an average amount of 5 wt% or less based on the total weight of the electrode-forming composition.

[0210] In one embodiment, the electrode-forming composition of the present invention comprises at least one conductive agent, preferably carbon black.

[0211] In the present invention, the choice of the organic solvent (S) is not particularly limited, provided that it is suitable for dissolving the partially fluorinated fluoropolymer of the present invention.

[0212] The organic solvent (S) is typically selected from the group consisting of:

[0213] - alcohols, such as methanol, ethanol, and diacetone alcohol;

[0214] - ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and isophorone;

[0215] - linear or cyclic esters, such as isopropyl acetate, n-butyl acetate, methyl acetoacetate, dimethyl phthalate, and γ-butyrolactone;

[0216] - linear or cyclic amides, such as N,N-diethylacetamide, N,N-dimethylacetamide, dimethylformamide, and N-methyl-2-pyrrolidone, and

[0217] - dimethyl sulfoxide.

[0218] The second object of the present invention is a method for manufacturing an electrochemical device, the method comprising the steps of:

[0219] (I) at least assembling

[0220] a) a positive electrode;

[0221] b) a negative electrode; and

[0222] c) a separator disposed between the positive electrode and the negative electrode,

[0223] wherein at least one electrode is a gel electrode obtained by the following method

[0224] - providing an electronically conductive substrate;

[0225] - providing a gel electrode forming composition;

[0226] - applying the gel electrode forming composition to the electronically conductive substrate;

[0227] - optionally, drying the electronically conductive substrate coated with the gel electrode forming composition; and

[0228] - calendering it into a film having a thickness between 80 μm and 900 μm, preferably between 100 μm and 800 μm, and more preferably between 200 μm and 600 μm.

[0229] (II) filling the assembled electrochemical device with a liquid medium (II) comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt.

[0230] In the present invention, the optional step of drying the electronically conductive substrate coated with the gel electrode forming composition is intended to evaporate the organic solvent (S).

[0231] In one embodiment, the gelation electrode-forming composition of the present invention comprises

[0232] i) at least one partially fluorinated fluoropolymer, the at least one partially fluorinated fluoropolymer comprising

[0233] - at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer,

[0234] - at least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group, and

[0235] - optionally, at least one third repeating unit derived from at least one fluorinated monomer different from the first repeating unit;

[0236] ii) at least one electroactive material;

[0237] iii) a liquid medium (I), the liquid medium comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt, and

[0238] iv) optionally, at least one conductive additive.

[0239] v) optionally, at least one organic solvent (S) different from the liquid medium (I).

[0240] In one embodiment, at least one first repeating unit is derived from vinylidene fluoride (VDF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), trifluoroethylene, and combinations thereof, and is preferably derived from VDF.

[0241] In a preferred embodiment, at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer is VDF.

[0242] In one embodiment, the step of applying the electrode-forming composition to an electronically conductive substrate is carried out by any suitable procedure such as casting, printing, roll coating, extrusion, and co-laminating.

[0243] In a specific embodiment, the step of applying the electrode-forming composition to an electronically conductive substrate is carried out at a temperature between 5 °C and 100 °C, preferably between 10 °C and 80 °C, and more preferably between 15 °C and 70 °C.

[0244] Another object of the present invention is to provide an electrochemical device, which comprises:

[0245] - a gelation positive electrode, the gelation positive electrode comprising an electronically conductive substrate and at least one layer of the gelation electrode-forming composition of the present invention directly adhered to the electronically conductive substrate;

[0246] - Negative electrode;

[0247] - A porous polymer material as a separator disposed between the positive electrode and the negative electrode, the porous polymer material being selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polyvinyl chloride, and combinations thereof, and

[0248] - A liquid electrolyte, which is a mixture of liquid medium (I) and liquid medium (II),

[0249] wherein the liquid medium (I) and the liquid medium (II) are the same or different; wherein the liquid medium (I) and the liquid medium (II) each contain at least one organic carbonate and / or at least one ionic liquid, and wherein at least one of the liquid medium (I) and the liquid medium (II) further contains at least one metal salt.

[0250] If the disclosure content of any patent, patent application, and publication incorporated by reference into this application conflicts with the description of this application to the extent that it may cause the terms to be unclear, then this description shall prevail.

[0251] The present invention will now be described with reference to the following examples, which are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0252] Experimental section

[0253] Raw materials

[0254] Polymer (FF-A): A VDF-AA (0.9 mol%)-HFP (2.4 mol%) polymer having a viscosity of 0.30 l / g in DMF at 25 °C.

[0255] Polymer (FF-B): A VDF-AA (0.9 mol%) polymer having a viscosity of 0.30 l / g in DMF at 25 °C.

[0256] Liquid medium - A (II): LP10: 1M LiPF 6 EC:PC:DMC (1:1:3), 2% VC; (where EC is ethylene carbonate, PC is propylene carbonate, DMC is dimethyl carbonate and VC is vinylene carbonate).

[0257] Liquid medium - B (I): 1M LiPF in EC:PC (1:1) + 2% VC 6 .

[0258] Graphite - A: 75% graphite SMG-N-HE1 (Hitachi Chemical Co., Ltd.) / 25% SFG 6.

[0259] Graphite - B: 75% graphite SMG - N - HE2 (Hitachi Chemical Co., Ltd.) / 25% SFG6.

[0260] Carbon black: C - SUPER C65 and Carbon fiber (CF).

[0261] Active material: NMC 622.

[0262] Example 1: Preparation of a prismatic battery cell:

[0263] Anode composition and preparation:

[0264] A solution of polymer (FF - A) in MEK (methyl ethyl ketone) was prepared at 38 °C and then brought to 19 °C. Then, graphite - B was added to the thus - obtained solution at a weight ratio of 95 / 5 (graphite - B / polymer (FF - A)). Then, liquid medium - B(I) was added to the solution. The weight ratio [m 电解质 / (m 电解质 +m 聚合物(FF-A) )]×100 is 80%.

[0265] Then the solution mixture was spread onto a copper current collector foil with a constant thickness using a machine roll - to - roll. The thickness was controlled by the distance between the knife and the metal current collector. Then the solvent was evaporated from the mixture at 60 °C to provide the electrode. The final thickness of the anode electrode was 242 microns. The electrode was calendered, and finally 5.51 mAh / cm 2 and a porosity of 35.7% were obtained.

[0266] Cathode composition and preparation:

[0267] A solution of polymer (FF - A) in acetone was prepared at 19 °C. Then carbon black and the active material were added to the solution at the following weight ratios: NMC 622 93 wt%; C65 2 wt%, VGCF 1 wt% and polymer (FF - A) 4 wt%. Then, liquid medium - B(I) was added to the solution. The weight ratio [m 电解质 / (m 电解质 +m 聚合物(FF-A) )]×100 is 75.2%.

[0268] Then, a solution mixture is spread onto a metallic current collector (aluminum foil) with a constant thickness using a roll-to-roll machine. The thickness is controlled by the distance between the knife and the metallic current collector. Then, the solvent is evaporated from the mixture to provide the electrode. The final thickness of the anode electrode is 248 micrometers. The electrode is calendered and finally obtains 5.0 mAh / cm 2 and 33.2% porosity.

[0269] Manufacture of a prismatic cell of a Li-ion battery:

[0270] According to the present invention, a separator is placed between the cathode and the anode 2320. Then, once the prismatic cell is assembled, a liquid medium - A(II) (2.16 ml) is introduced into the prismatic cell to fill the pores of the separator and the electrodes that have not been filled with the liquid medium - B(I). The electrolyte already in the electrodes plus this amount of the liquid medium - B(I) accounts for a total excess of 107% of the total porosity of the electrochemical core of the cell (electrodes plus separator).

[0271] The prismatic cell of Example 1 is shown in Figure 1 the figure.

[0272] The discharge capacity values of 4 prismatic cells according to the present invention at different discharge rates are shown in Table 1. It is obvious that they all work properly and they are reproducible as equivalent cells. All have the same performance.

[0273] Table 1:

[0274]

[0275]

[0276] The electrodes of the prismatic cell according to the present invention have a very high degree of flexibility. In Figure 2 (a) and (b), the electrodes (anode and cathode respectively) of the prismatic cell taken out and unfolded from the prismatic cell are shown. No signs of damage are observed.

[0277] Comparative Example 1: Preparation of a Standard Prismatic Battery Cell

[0278] Anode composition and preparation:

[0279] A solution of polymer (FF-B) in NMP (N-methyl-2-pyrrolidone) was prepared at room temperature with stirring. Then, graphite-A was added to the solution thus obtained at a weight ratio of 95 / 5 (graphite-A / polymer (FF-B)). Then, the solution mixture was spread onto a metal current collector (copper foil) with a constant thickness using a roll-to-roll machine. The thickness was controlled by the distance between the knife and the metal current collector. Thus, the wet electrode was dried to obtain a final thickness of 258 μm for the anode electrode. The electrode was calendered to finally obtain 5.90 mAh / cm 2 and a porosity of 35%.

[0280] Cathode composition and preparation:

[0281] A solution of polymer (FF-B) in NMP was prepared at room temperature with stirring. Then, carbon black and active materials were added to the solution at the following weight ratios: NMC 622 93 wt%; C65 2 wt%, VGCF 1 wt% and polymer (FF-B) 4 wt%.

[0282] Then, the solution mixture was spread onto a metal current collector (aluminum foil) with a constant thickness using a roll-to-roll machine. The thickness was controlled by the distance between the knife and the metal current collector. Thus, the wet electrode was dried to obtain a final thickness of 219 μm for the anode electrode. The electrode was calendered to finally obtain 4.77 mAh / cm 2 and a porosity of 28.5%.

[0283] Manufacture of prismatic battery cells for Li-ion batteries:

[0284] A separator was placed between the cathode and the anode 2320. Then, once the prismatic battery cell was assembled, liquid medium-A (II) was introduced into the prismatic battery cell, which had an excess of approximately 25% over the total porosity present in the battery cell (i.e., the sum of the porosities of the separator and the two electrodes (about 2.36 ml)).

[0285] The discharge capacity values of 6 prismatic battery cells at different discharge rates are shown in Table 2. It is obvious that not all of them work properly, and in any case, they are not reproducible as equivalent battery cells. All have different performances.

[0286] Table 2

[0287]

[0288]

[0289] The standard electrode of the prismatic battery cell of Comparative Example 1 showed a lack of flexibility. At Figure 3In (a) and (b), the electrodes (anode and cathode, respectively) of a prismatic battery cell removed from and unfolded from the prismatic battery cell are shown. It can be clearly seen that when inside the battery cell, corresponding to the regions where the electrodes are bent, a considerable amount of damage has occurred.

[0290] Comparative Example 2

[0291] In this example, the procedure of Comparative Example 1 was repeated, but an excess of electrolyte of approximately 100% (instead of 25%) was added. As shown in Table 3, there was no change in the results and lack of reproducibility.

[0292] Table 3

[0293]

Claims

1. An electrochemical device, comprising a) a positive electrode, b) a negative electrode, c) a separator, and d) a liquid electrolyte, wherein at least one of the positive electrode and the negative electrode is a gelled electrode, the gelled electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition directly adhered to the electronically conductive substrate, and wherein the d) liquid electrolyte comprises at least one organic carbonate and / or at least one ionic liquid, and at least one metal salt; and wherein, the gelled electrode-forming composition comprises i) at least one partially fluorinated fluoropolymer, the at least one partially fluorinated fluoropolymer comprising - at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer, and - at least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group; ii) at least one electroactive compound; iii) a liquid medium I; iv) optionally, at least one conductive additive; and v) optionally, at least one organic solvent different from the liquid medium I, wherein the liquid medium I comprises at least one organic carbonate and / or at least one ionic liquid.

2. The electrochemical device according to claim 1, wherein, the c) separator and a liquid medium II comprising at least one organic carbonate and / or at least one ionic liquid are placed between the a) positive electrode and the b) negative electrode, and wherein the d) liquid electrolyte is a mixture of the liquid medium I and the liquid medium II.

3. The electrochemical device according to claim 2, wherein, the liquid medium I and the liquid medium II are the same or different, and at least one of the liquid medium I and the liquid medium II further comprises at least one metal salt.

4. The electrochemical device according to any one of claims 1 to 3, wherein, at least one of the positive electrode and the negative electrode has a thickness between 80 µm and 900 µm.

5. The electrochemical device according to claim 4, wherein, at least one of the positive electrode and the negative electrode has a thickness between 100 µm and 800 µm.

6. The electrochemical device according to claim 5, wherein, at least one of the positive electrode and the negative electrode has a thickness between 200 µm and 600 µm.

7. The electrochemical device according to any one of claims 1 to 3, wherein, the c) separator is a porous polymeric material.

8. The electrochemical device according to any one of claims 1 to 3, wherein, the at least one first repeating unit is derived from vinylidene fluoride, chlorotrifluoroethylene, hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, and combinations thereof.

9. The electrochemical device according to claim 8, wherein, the at least one first repeating unit is derived from vinylidene fluoride.

10. The electrochemical device according to any one of claims 1 to 3, wherein, the at least one second repeating unit is selected from the group consisting of (meth)acrylic monomers having formula (I): wherein R 1 , R 2 and R 3 each of which is the same as or different from one another, independently is a hydrogen atom or a C 1 -C 3 hydrocarbyl group.

11. The electrochemical device according to any one of claims 1 to 3, wherein, The (i) partially fluorinated fluoropolymer additionally comprises a third repeating unit derived from at least one fluorinated monomer that is different from the first repeating unit.

12. The electrochemical device according to any one of claims 1 to 3, wherein, Loading the ii) at least one electroactive compound onto the electronically conductive substrate to have areal capacity between 1.0 mAh / cm 2 and 9.0 mAh / cm 2 2.

13. The electrochemical device according to claim 12, wherein, Loading the ii) at least one electroactive compound onto the electronically conductive substrate to have areal capacity between 4.0 mAh / cm 2 and 7.0 mAh / cm 2 2.

14. The electrochemical device according to any one of claims 1 to 3, wherein, the metal salt is selected from the group consisting of: a) MeI, Me(PF 6 ) n 、Me(BF 4 ) n 、Me(ClO 4 ) n 、Me( bis(oxalato)borate) n 、MeCF 3 SO 3 、Me[N(SO 2 F) 2 ) n 、Me[N(CF 3 SO 2 ) 2 ) n 、Me[N(C 2 F 5 SO 2 ) 2 ) n 、Me(AsF 6 ) n 、Me[C(CF 3 SO 2 ) 3 ) n、 Me 2 S n 、Me[N(CF 3 SO 2 )(R F SO 2 )] n , where R F is C 2 F 5 , C 4 F 9 or CF 3 OCF 2 CF 2 , where Me is a metal and n is the valence of said metal; b) wherein R' F is selected from the group consisting of: F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 2 F 5 , C 3 H 4 F 3 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 3 F 5 OCF 3 , C 2 F 4 OCF 3 , C 2 H 2 F 2 OCF 3 and CF 2 OCF 3 ; and c) combinations thereof.

15. The electrochemical device according to claim 14, wherein, in group a), Me is a transition metal, an alkali metal or an alkaline earth metal.

16. The electrochemical device according to claim 15, wherein, in group a), Me is Li, Na, K or Cs.

17. The electrochemical device according to claim 16, wherein, in group a), Me is Li.

18. The electrochemical device according to claim 14, wherein, in group a), n is 1 or 2.

19. A method for manufacturing an electrochemical device, the method comprises the following steps: (I) at least assembling a positive electrode; a negative electrode; and a separator disposed between the positive electrode and the negative electrode, wherein at least one electrode is a gelled electrode obtained by the following method - providing an electronically conductive substrate; - providing a gelled electrode forming composition; - applying the gelled electrode forming composition to the electronically conductive substrate; - optionally, drying the electronically conductive substrate coated with the gelled electrode forming composition; and - calendering it into a film having a thickness between 80 µm and 900 µm, and (II) filling the assembled electrochemical device with a liquid medium II comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt; and wherein the gelled electrode forming composition comprises i) at least one partially fluorinated fluoropolymer, the at least one partially fluorinated fluoropolymer comprising - at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer, - at least one second repeating unit derived from at least one hydrogenated monomer comprising at least one carboxyl group, and - optionally, a third repeating unit derived from at least one fluorinated monomer that is different from the first repeating unit; ii) at least one electroactive material; iii) a liquid medium I, the liquid medium comprising at least one organic carbonate and / or at least one ionic liquid and optionally at least one metal salt; iv) optionally, at least one conductive additive; and v) optionally, at least one organic solvent different from the liquid medium I.

20. The method according to claim 19, wherein, the film has a thickness between 100 µm and 800 µm.

21. The method according to claim 20, wherein, the film has a thickness between 200 µm and 600 µm.

22. The method according to claim 19, wherein, the at least one first repeating unit derived from at least one ethylenically unsaturated fluorinated monomer is VDF.

23. An electrochemical device, which comprises - A gelled positive electrode, the gelled positive electrode comprising an electronically conductive substrate and at least one layer of a gelled electrode-forming composition as defined in any one of claims 1 to 18 directly adhered to the electronically conductive substrate; - A negative electrode; - A porous polymer material as a separator disposed between the positive electrode and the negative electrode, the porous polymer material selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polyvinyl chloride, and combinations thereof, and - A liquid electrolyte, the liquid electrolyte being a mixture of a liquid medium I and a liquid medium II, wherein the liquid medium I and the liquid medium II are the same or different; wherein the liquid medium I and the liquid medium II each contain at least one organic carbonate and / or at least one ionic liquid, and wherein at least one of the liquid medium I and the liquid medium II additionally contains at least one metal salt.

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