Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/665—Composites
  • H01M4/666—Composites in the form of mixed materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/665—Composites
  • H01M4/667—Composites in the form of layers, e.g. coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/70—Carriers or collectors characterised by shape or form
  • H01M4/80—Porous plates, e.g. sintered carriers
  • H01M4/806—Nonwoven fibrous fabric containing only fibres
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/027—Negative electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/028—Positive electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the technical field generally concerns self-supporting electrodes, their methods of manufacture and their use in electrochemical cells, for example in lithium-ion batteries.
• BLIs lithium-ion batteries
• microfibrillated cellulose and highly refined cellulose fibers dispersed in water can be used effectively as a binder for the manufacture of self-supporting negative electrodes with very good electrochemical and mechanical performances (see Jabbour, L. et al., Journal of Materials Chemistry 20: 35 (2010): 7344-7347 and Jabbour, L. et al, Journal of Materials Chemistry 22.7 (2012): 3227-3233).
• chemical, enzymatic, and acid hydrolysis treatments are required in order to obtain fibers having a diameter of between 5 and 250 nm, thus increasing the costs and preparation time of self-supporting films (see Jabbour, L. et al. al., Cellulose 20.4 (2013): 1523-1545).
• an aluminum current collector is at least 40% of the total mass of an iron phosphate lithium electrode (LiFePCL or LFP) with a load of about 6 mg / cm 2 of active material. Replacing the aluminum current collector mass with light current collectors comprising carbon and / or carbon fibers results in a more conductive film and better performance.
• the inactive metal current collector sheets not only increase the overall weight of the cell, but may also be affected by corrosion problems (see Zhang, SS et al., Journal of Power Sources 109.2 (2002): 458). -464).
• Organic electrodes could, for example, reduce battery manufacturing costs because organic materials can be prepared from natural products or biomass (see Chen, H. et al., ChemSusChem: Chemistry & Sustainability Energy & Materials 1.4 ( 2008): 348-355).
• batteries containing organic materials can be more environmentally friendly and fully recyclable. Therefore, there is a need for self-supporting electrodes excluding one or more of the disadvantages encountered with conventional electrodes. There is also a need for more simple and efficient freestanding electrode fabrication methods.
• the present technology relates to a self-supporting electrode comprising:
• a first electron conducting material serving as a current collector, the surface of said first electronically conductive material being grafted with at least one aryl group of Formula I:
• FG is a hydrophilic functional group
• n is a natural integer in the range of 1 to 5, preferably n is in the range of 1 to 3, preferably n is 1 or 2, or more preferably n is 1;
• a binder comprising cellulose fibers
• the self-supporting electrode consists of a solid film having first and second surfaces
• the concentration of the first electronically conductive material increases from the second surface to the first surface of the solid film
• the concentration of the electrochemically active material increases from the first surface to the second surface of the solid film.
• the self-supporting electrode as defined herein further comprises a second electronically conductive material, the concentration of said second electronically conductive material increasing from the first surface to the second surface of the solid film.
• the first electronically conductive material comprises carbon fibers.
• carbon fibers are carbon fibers formed in the gas phase (VGCFs).
• the cellulose fibers are unmodified cellulose fibers.
• the average length of the cellulose fibers is between 5 nm and 5 mm, or between 250 nm and 3 mm, or between 500 nm and 3 mm, or between 1 ⁇ m and 3 mm, or between 100 ⁇ m and 3 mm. , or between 250 pm and 3 mm, or between 500 pm and 3 mm, or between 750 pm and 2.5 mm, or between 1 mm and 2.5 mm.
• the electrochemically active material is in the form of particles coated with a carbon layer in a core-shell configuration.
• said carbon layer may be grafted with at least one aryl group of Formula I.
• the electrochemically active material is selected from metal oxide particles, lithiated metal oxide particles, metal phosphate particles, lithiated metal phosphate particles, carbon and organic active materials.
• the metal is a transition metal selected from titanium (Ti), iron (Fe), manganese (Mn), vanadium (V), nickel (Ni), cobalt (Co) and a combination at least two of these.
• the self-supporting electrode is a positive electrode.
• the electrochemically active material comprises lithiated iron phosphate particles (LiFePO 4 or LFP) or comprises pyromellitic dianhydride (PMDA), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) or perylene dianhydride. -3,4,9,10-tetracarboxylic acid (PTCDA).
• the self-supporting electrode is a negative electrode.
• the electrochemically active material comprises particles of lithium titanate (Li 4 Ti 5 O 12, also called LTO) or a carbon-based material.
• the carbon-based material is graphene or graphite.
• the second electronically conductive material is selected from carbon black, acetylene black, graphite, graphene, carbon fibers, carbon nanofibers, carbon nanotubes and a combination of at least two of these.
• the second electronically conductive material is selected from acetylene black (such as Denka black MC ), carbon fibers, carbon nanotubes, and combinations thereof.
• the second electronically conductive material comprises carbon fibers, a combination of carbon fibers and acetylene black (such as Denka Black MC ), or a combination of carbon fibers and carbon nanotubes.
• carbon fibers are carbon fibers formed in the gas phase (VGCFs). The carbon fibers may be present in the combination at a concentration of at least 50% by weight.
• the second electronically conductive material is further grafted with at least one aryl group of Formula I.
• the hydrophilic functional group is a carboxylic acid or sulfonic acid group.
• the aryl group of Formula I is p-benzoic acid or p-benzenesulfonic acid.
• the present technology relates to a method for manufacturing a self-supporting electrode as defined herein, the method comprising the following steps:
• step (e) filtering the second aqueous dispersion on the film obtained in step (c) to produce a self-supporting electrode on the filter membrane;
• the film obtained in step (c) comprises a rich side of first electronically conductive material and a rich fiber fiber side, the rich side of first electronically conductive material facing the filter membrane.
• the electrochemically active material is in the form of particles coated with a carbon layer and the method further comprises a grafting step of at least one aryl group of Formula I on said carbon layer before the step (d).
• the method as defined herein further comprises a step of calendering the self-supporting electrode.
• the calendering step is carried out at a temperature between room temperature and about 80 ° C.
• the present process further comprises a step of preparing a separator by filtering an aqueous mixture comprising cellulose fibers directly onto the self-supporting electrode obtained in step (e), prior to step (f).
• the method as defined herein further comprises a step of grafting at least one aryl group of Formula I onto the second electronically conductive material before step (d).
• the grafting steps of the process include:
• step (ii) reacting the aryl diazonium ion generated in step (i) with the first or second electronically conductive material, or with the carbon layer on the electrochemically active material.
• the diazotization agent is present in a range of values from 0.01 to 0.04 equivalents to carbon, or about 0.03 equivalents to carbon.
• the diazotising agent is present in an amount in the range of 1 to 4 molar equivalents relative to the aniline of Formula II, or about 3 molar equivalents relative to aniline of Formula II.
• the diazotising agent is a nitrite salt or an alkyl nitrite, such as sodium nitrite (NaNC 2) or tert-butyl nitrite (t-BuONO).
• the aryl diazonium ion is generated in situ so that steps (i) and (ii) are performed simultaneously.
• the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein at least one of the negative and positive electrodes is a self-supporting electrode as defined herein.
• the negative electrode and the positive electrode are both self-supporting electrodes.
• the present electrochemical cell further comprises a separator.
• the separator is a polypropylene separator (PP), a polypropylene-polyethylene-polypropylene separator (PP / PE / PP) or a cellulosic separator.
• the separator is a cellulosic separator.
• the cellulosic separator is produced by filtration of an aqueous mixture comprising cellulose fibers directly onto the surface rich in electrochemically active material of the self-supporting electrode.
• the electrolyte is a liquid electrolyte comprising a lithium salt in a solvent.
• the electrolyte is a gel electrolyte comprising a lithium salt in a solvent and optionally a solvating polymer.
• the electrolyte is a solid polymer electrolyte comprising a lithium salt in a solvating polymer.
• the present technology relates to a battery comprising at least one electrochemical cell as defined herein.
• the battery is a lithium or lithium-ion battery, a sodium or sodium-ion battery, and a magnesium or magnesium ion battery.
• the battery is a lithium-ion battery.
• Figure 1 schematically illustrates the process for preparing flexible self-supporting electrodes according to one embodiment.
• Figure 2 shows photographs of a film described in Example 1 (d) showing in (A) a rich side of electronically conductive material; (B) a side rich in cellulose fibers; and (C) flexibility and thin film thickness.
• Figure 3 shows photographs of a self-supporting electrode described in Example 1 (d) showing in (A) a rich side of electronically conductive material; (B) the electrochemically active material filling the pores of the rich cellulose fiber side; (C) the film remains intact and strong even after cutting a small electrode; and (D) a self-supporting electrode-separator film as described in Example 1 (e).
• Figure 4 shows the results of cyclic voltammetry of a paper electrode (dashed line) and a bare electrode (or reference) as described in Example 3 (solid line).
• Figure 5 shows the cyclic voltammograms of a self-supporting electrode recorded with a self-supporting electrode with integrated paper separator as described in Example 1 (e) (dashed line) and a self-supporting electrode as described in Example 1 ( d) using a Celgard TM separator (solid line).
• Figure 6 shows the results (A) of cyclic voltammetry; and (B) capacity versus number of cycles at charge and discharge regimes between C / 10 and 5C, obtained with three self-supporting electrodes respectively containing unmodified VGCFs, VGCFs-COOH, and VGCFS-SO 3 H. Solid and empty symbols are used in (B) to represent the results in load and discharge, respectively.
• Figure 7 shows photographs of (A) the self-supporting LFP electrode comprising unmodified VGCFs, and (B) the self-supporting LFP electrode comprising VGCFs-COOH.
• Figure 8 presents the capacity results versus number of cycles at charge / discharge regimes between C / 10 and 5C recorded with (A) a combination of VGCFs-COOH and Denka-COOFI or a combination of VGCFS- SO 3 FI and Denka-SOsH; and (B) a combination of VGCFs-COOFI and NTCs-COOFI or a combination of VGCFS-SO 3 FI and NTCS-SO 3 FI. Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 9 shows the results (A) of cyclic voltammetry; and (B) capacity versus number of cycles at charge and discharge regimes between C / 10 and 5C, obtained with two LFP electrodes comprising a mixture of carbons VGCFs-COOFI and NTCs-COOFI, one calendered at a temperature of 25 ° C and the other at 50 ° C.
• the solid and empty symbols are used in (B) to represent the results in charge and discharge, respectively.
• Figure 10 shows capacity results versus number of cycles at load and discharge regimes between C / 10 and 5C, for LFP electrodes made with the modified LFP-COOFI material and calendered at 25 ° C and 25 ° C. 80 ° C. Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 11 presents the results (A) of cyclic voltammetry; and (B) capacity versus number of cycles at charge and discharge regimes between C / 10 and 5C, obtained with four electrodes comprising different amounts of LTO and VGCFS-SO 3 H. The solid and empty symbols are used in (B) to represent the results in charge and discharge, respectively.
• Figure 12 shows the results (A) of cyclic voltammetry; and (B) capacitance versus number of cycles at charge and discharge regimes between C / 10 and 5C, obtained with three different LTO electrodes including VGCFs-COOFI, a mixture of VGCFs-COOFI and NTCs- COOFI, or a mixture of VGCFs-COOFI and Denka-COOFI.
• FIG. 13 shows the specific capacitance results over 300 cycles at a C / 2 constant charge / discharge current of between 1, 2 and 2.5 V vs Li / Li + recorded with two LTO electrodes, one containing VGCFs-COOH, the other containing a mixture of VGCFs-COOH and NTCs-COOH.
• Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 15 shows capacity results versus number of cycles at charging and discharging regimes between C / 24 and 5C, for LFP / LTO batteries manufactured with different amounts of LFP and LTO and with ratios by weight LFP / LTO of 1 or about 0.85.
• Kodoshi TM paper separators were used for all electrodes. Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 16 shows the specific capacity results over 200 cycles at a constant charge / discharge current of C / 2 between 1.0 and 2.5 V vs. LTO, where stability is compared for (A) LFP / LTO batteries identical except for the use of Celgard TM (square) and Kodoshi TM paper (circles) separators; and (B) batteries LFP / LTO using Kodoshi MC paper separators and different amounts of LFP and LFP with a ratio LTO / LTO by weight of 1 or about 0.85. Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 17 shows the results of specific capacity over 1000 cycles at a constant charging / discharging current of 2C between 1.0 and 2.5 V vs. LTO for LFP / LTO batteries by varying the amount of LFP and LTO with a LFP / LTO ratio by weight of 1 and Kodoshi TM paper separators. Solid and empty symbols are used to represent the load and discharge results, respectively.
• Figure 18 shows the results (A) of cyclic voltammetry at a scan rate of 0.03 mV / s; and (B) discharge capacity and coulombic efficiency as a function of the number of cycles at regimes between C / 24 and 5C, obtained with three self-supporting organic electrodes containing a mixture of VGCFS-SO3H, NTCS-SO3FI and various amounts of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• Figure 19 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles at a constant charge / discharge current of C / 10 between 1.5 and 3.5 V vs Li / Li + , obtained with two self-supporting organic electrodes containing (A) VGCFs-SO 3 H and PTCDA; and (B) a mixture of VGCFS-SO 3 H, NTCS-SO 3 FI and PTCDA. Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• the insertions in (A) and (B) represent the discharge capacity results at different C levels performed prior to the long cycling experiment.
• Figure 20 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles at a constant charge / discharge current of C / 10 between 1.5 and 3.5.
• V vs Li / Li + obtained with two freestanding PTCDA electrodes containing VGCFS-SO3FI (squares), and a mixture of VGCFS-SO3FI and NTCS-SO3FI (circles), respectively. Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• Figure 21 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles at a constant charge / discharge current of C / 10 between 1.5 and 3.5 V vs. Li / Li + , obtained with three self-supporting PTCDA electrodes containing a mixture of VGCFs-SO3H and NTCS-SO3H, and different amounts of PTCDA. Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• Figure 22 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles at a constant charge / discharge current of C / 10 between 0 and 1.5 V vs Li / Li + , obtained with two electrodes.
• graphite one containing VGCFS-SO3FI (squares), the other containing a mixture of VGCFS-SO3FI and NTCS-SO3FI (circles). Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• Figure 23 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles at a constant charge / discharge current of C / 10 between 0 and 1.5.
• V vs Li / Li + obtained with (A) two VGCFS-SO3FI containing electrodes and 30 mg or 40 mg of graphite, and (B) three VGCFS-SO3FI containing electrodes and 30 mg, 40 mg, or 50 mg of graphite SOsFI.
• Solid and empty symbols are used to represent coulombic efficiency (%) and discharge capacity, respectively.
• Figure 24 shows (A) the first charge and discharge obtained at a constant current of C / 24 between 2 and 4 V vs graphite for an LFP / graphite battery using Kodoshi TM paper separators and an anode excess capacity; and (B) the corresponding long cycling experiment performed at a 1C regime.
• the solid and empty symbols are used in (B) to represent the results in charge and discharge, respectively.
• FIG. 25 shows the first discharge results (A) obtained at a constant current of C / 24 of open circuit potential (OCP) at 1.5 V vs. Li / Li + for three different PTCDA / lithium metal batteries comprising different quantities PTCDA; and (B) chronoamperometry performed directly after the first discharge for these three batteries with a potential set at 1.5 V vs Li / Li + for 3 h.
• OCP open circuit potential
• Figure 26 shows the first charge and discharge (A) results obtained at a constant C / 24 current between 1.5 and 3.5 V vs graphite for two prelithied PTCDA / graphite batteries using Kodoshi TM paper separators and an anode excess in capacitance. ; and (B) a corresponding long cycling experiment performed on the same batteries at a C / 10 rate after 5C formation.
• the solid and empty symbols are used in (B) to represent the results in charge and discharge, respectively.
• self-supporting electrode refers to an electrode without a metal current collector.
• organic semiconductor refers to pi-bonded molecules or polymers comprising carbon atoms and hydrogen atoms.
• the molecule or polymer may further comprise heteroatoms (such as N, S and O).
• aryl refers to substituted or unsubstituted aromatic rings, the contributing atoms being able to form a ring or a plurality of fused rings.
• Representative aryl groups include groups having from 6 to 14 ring members.
• aryl may include phenyl, naphthyl, etc.
• the aromatic ring may be substituted at one or more ring positions with, for example, a carboxyl (-COOH) or sulfonic acid (-SO 3 H) group, an amine group, and the like.
• hydrophilic functional group refers to functional groups attracted to water molecules.
• the hydrophilic functional groups can generally be charged and / or capable of forming hydrogen bridges.
• Non-limiting examples of hydrophilic functional groups include hydroxyl, carboxylic acid, sulfonic acid, phosphonic acid, amine, amide and the like. The term further includes salts of these groups, if any.
• the present application describes self-supporting electrodes, for example, flexible self-supporting electrodes.
• the present application also describes a water-based filtration process inspired by the paper industry for the manufacture of self-supporting electrodes.
• the present application also describes the use of these self-supporting electrodes in electrochemical cells.
• the present application describes the use of self-supporting electrodes in lithium-ion batteries (BLIs).
• the present self-supporting electrodes and their method of manufacture exclude one or more of the following: a current collector (eg, aluminum or copper current collector), an expensive binder, or a harmful solvent (eg, N-methyl) -2-pyrrolidone (NMP)).
• NMP harmful solvent
• the self-supporting electrodes obtained by the present process can also be recyclable.
• the process of the present application uses unmodified cellulose as a binder for the self-supporting electrodes.
• Unmodified cellulose is an abundant, natural and inexpensive polymer.
• the process of the present application is relatively simple, fast, and easily adaptable to industrial production.
• the present process may use only water as the solvent.
• the present process may also involve the preparation of soluble (dispersible) carbons in water which can accelerate the preparation and / or facilitate the dispersion of the electrode materials in the water.
• soluble (dispersible) carbons in water can accelerate the preparation and / or facilitate the dispersion of the electrode materials in the water.
• an improvement in the distribution of these modified carbons in the electrode may allow the improvement of the electrochemical performances.
• LFP low-density polystyrene
• PTCDA perylene-3,4,9,10-tetracarboxylic dianhydride
• LTO electrodes having good mechanical strengths
• the self-supporting electrodes of the present application remain substantially intact (in their original state), even after the punching of the self-supporting electrodes, after the cycling and / or even after the opening of the electrochemical cells.
• the electrochemical performances of the present positive and / or negative self-supporting electrodes tested are at least similar to those commonly reported for LFP and / or LTO electrodes extended on metal current collectors (for example, aluminum or aluminum current collector). copper) following a traditional manufacturing process. Electrochemical cells generally maintain good stability and a substantially high specific capacity, even during long-term cycling.
• the present technology therefore relates to a self-supporting electrode comprising:
• a first electronically conductive material serving as a current collector, the surface of said first electronically conductive material being grafted with at least one aryl group of Formula I:
• FG is a hydrophilic functional group
• n is a natural integer in the range of 1 to 5, preferably n is in the range of 1 to 3, preferably n is 1 or 2, or more preferably n is 1;
• a binder comprising cellulose fibers
• the self-supporting electrode consists of a solid film having first and second surfaces
• the concentration of the first electronically conductive material increases from the second surface to the first surface of the solid film
• the concentration of the electrochemically active material, and optionally the second electronically conductive material increases from the first surface to the second surface of the solid film.
• the first surface mainly comprises the first electronically conductive material.
• the first electronically conductive material may comprise carbon fibers, such as gas phase carbon fibers (VGCFs).
• hydrophilic functional groups include hydroxyl, carboxylic acid, sulfonic acid, phosphonic acid, amine, amide and the like.
• the hydrophilic functional group is a carboxylic acid or sulphonic acid functional group.
• Preferred examples of the aryl group of Formula I are p-benzoic acid or p-benzenesulfonic acid.
• the binder comprises cellulose fibers, in particular unmodified cellulose fibers.
• unmodified cellulose fibers do not contain aluminum cations.
• conventional cellulose fibers are often modified with hydrated aluminum sulfate as an adjuvant, thereby neutralizing the negative charge present on the cellulose fibers by aluminum cations.
• the cellulose fibers of the present application are not modified with hydrated aluminum sulphate, since this compound may possibly react inside the batteries, for example, during cycling.
• the average length of the cellulose fibers is between 5 nm and 5 mm, or between 250 nm and 3 mm, or between 500 nm and 3 mm, or between 1 ⁇ m and 3 mm, or between 100 ⁇ m and 3 ⁇ m. mm, or between 250 pm and 3 mm, or between 500 pm and 3 mm, or between 750 pm and 2.5 mm, or between 1 mm and 2.5 mm.
• the second surface of the present self-supporting electrode mainly comprises the electrochemically active material and, optionally, the second electronically conductive material.
• the electrochemically active material may be in the form of particles.
• the electrochemically active material may be in the form of particles coated with a carbon layer in a core-shell configuration.
• the carbon layer may also be optionally grafted with at least one aryl group of Formula I.
• Non-limiting examples of electrochemically active material include materials such as metal phosphate, lithiated metal phosphate, metal oxide, and lithiated metal oxide, for example, the metal is a transition metal selected from Ti, Fe, Mn, V, Ni, Co and their combinations.
• the electrochemically active material comprises a lithiated metal phosphate or not (e.g., LiM'PC> 4 and M'P0 4 where M 'is Fe, Ni, Mn, Co or a combination thereof), an oxide of vanadium (for example, LiV 3 Os, V 2 O 5 , UV 2 O 5 , etc.), other lithiated metal oxides such as LiMn 2 0 4 , LiM "C> 2 (M" being Mn, Co, Ni or a combination thereof), Li (NiM "') 0 2 (where M" is Mn, Co, Al, Fe, Cr, Ti, Zr and the like, or a combination thereof), a lithium titanate or titanate (eg, T1O 2 , Li 2 TiC 3 , LLT 1 5 O 12 , H 2 T1 5 O 11 , H 2 TLO 9 or a combination thereof), or a combination of two or more of the above materials when compatible.
• a lithium titanate or titanate eg, T1O
• the electrochemically active material may, for example, include particles of lithium metal phosphate (such as LiFePO 4 , also called LFP).
• the electrochemically active material may, for example, comprise particles of lithium titanate (such as LLTisO 3, also called LTO).
• the electrochemically active material may be a carbon-based material such as graphene or graphite.
• the electrochemically active material may also be an organic active material such as an electrode material comprising an active material of polymer or polyaromatic type.
• the organic active material may be an organic semiconductor.
• Non-limiting examples of organic active material include dianhydride-based polymers such as pyromellitic dianhydride (PMDA), naphthalene-1, 4,5,8-tetracarboxylic dianhydride (NTCDA) and 3,4,9-perylene dianhydride. , 10-tetracarboxylic acid (PTCDA).
• PMDA pyromellitic dianhydride
• NTCDA naphthalene-1, 4,5,8-tetracarboxylic dianhydride
• PTCDA 10-tetracarboxylic acid
• the organic active material based on dianhydride is PTCDA.
• the PTCDA can, for example, be chosen for its low cost or for its theoretical capacity of 273 mAh / g.
• the dianhydride-based polymer can be of Formula III (a), II (b) or III (c):
• the electrochemical performance (capacitance and coulombic efficiency) obtained with self-supporting positive electrodes including PTCDA are significantly improved over those commonly reported for positive PTCDA electrodes and for lower electrochemically active material charges (see Sharma , P. et al., The Journal of Physical Chemistry Letters 4.19 (2013): 3192-3197).
• the organic active material may comprise a quinone derivative, such as an anthraquinone.
• the second electronically conductive material is optionally grafted with at least one aryl group of Formula I.
• second electronically conductive material include carbon black (such as Ketjen TM carbon), acetylene black (such as Shawinigan carbon and Denka TM carbon), graphite, graphene, carbon fiber, and carbon fiber. carbon (such as carbon nanofibers or VGCFs), and carbon nanotubes (NTCs), or a combination of at least two thereof.
• the second electronically conductive material may comprise at least one of the materials selected from acetylene black (such as Denka MC ), carbon fiber (VGCFs), carbon nanotubes, and combinations thereof.
• the second electronically conductive material comprises VGCFs, a combination of VGCFs and Denka MC TM or a combination of VGCFs and NTCs.
• the VGCFs are present in combination with another electronically conductive material (for example NTCs or Denka MC )
• the VGCFs are present in the combination at a concentration of 50% by weight or more.
• the present technology relates to a method for producing self-supporting electrodes, the method comprising the following steps:
• step (b) dispersing the first modified electronically conductive material obtained in step (a) in an aqueous mixture comprising cellulose fibers to obtain a first aqueous dispersion;
• step (e) filtering the second aqueous dispersion on the film obtained in step (c) to produce a self-supporting electrode on the filter membrane;
• the grafting of an aryl group on a carbon layer present on the surface of the electrochemically active material can be carried out as illustrated in Scheme 2:
• the method further comprises a step of grafting at least one aryl group of Formula I onto the second electronically conductive material before step (d).
• the grafting of an aryl group of Formula I onto the electronically conductive material can be carried out as illustrated in Scheme 1.
• the grafting steps of the process comprise:
• step (ii) reacting the aryl diazonium ions generated in step (i) with a carbon layer on the surface of the electrochemically active material, or with the first or second electronically conductive material.
• the aryl diazonium ion is generated in situ, that is to say that step (i) is carried out in the presence of the carbon layer of the electrochemically active material or alternatively of the first or second electronically conductive material of step (ii).
• the diazonium ion reacts, as and when it is formed, with the carbon of the carbon layer or, alternatively, of the first or second electronically conductive material.
• the aryl diazonium ion may also be generated before the addition of the electrochemically active material, or the first or second electronically conductive material.
• the diazonium ion can be generated before it is added to the electrochemically active material or to the first or second electronically conductive material.
• the amount of diazotization agent used may be in the range of 1 to 4 molar equivalents, preferably about 3 molar equivalents, based on aniline. In one example, the amount of diazotization agent used may be in the range of 0.01 to 0.04 equivalents to carbon.
• the diazotising agent is a nitrite salt or an alkyl nitrite.
• the diazotizing agent may be a nitrite salt, for example, sodium nitrite (NaNC 2).
• the diazotizing agent may be an alkyl nitrite, for example, tert-butyl nitrite (f-BuONO).
• the grafting step when the grafting step is performed on the first or second electronically conductive material, it may be carried out in an acidic aqueous medium.
• the aqueous acidic medium may be an aqueous solution of sulfuric acid (H2SO4).
• H2SO4 sulfuric acid
• the grafting step when the grafting step is performed on the carbon layer on the surface of the electrochemically active material, it may be carried out in an aprotic polar solvent such as acetonitrile.
• the film obtained in step (c) comprises a rich side of first electronically conductive material and a rich fiber fiber side, the rich side of first electronically conductive material facing the filter membrane.
• the method further comprises a step of drying the film obtained in step (c).
• the electrochemically active material is in the form of particles coated with a carbon layer and the method also comprises a grafting step of at least one aryl group of Formula I on said carbon layer before the step (d).
• the method further comprises a step of calendering the self-supporting electrode.
• the calendering step can be carried out at a temperature between room temperature and about 80 ° C, for example, in the range of about 25 ° C to about 80 ° C.
• the calendering step can be carried out at room temperature.
• the calendering step can be carried out at a temperature in the range of about 50 ° C to about 80 ° C.
• the method further comprises a step of producing a separator by filtration of an aqueous mixture comprising cellulose fibers directly on the self-supporting electrode produced in step (e), the production step a separator then being generally performed before step (f).
• the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein at least one of the negative and positive electrodes is a self-supporting electrode as defined herein.
• the negative electrode and the positive electrode are both self-supporting electrodes as defined herein.
• the electrochemical cell further comprises a separator.
• separators may comprise polyethylene (PE), polypropylene (PP), cellulose, polytetrafluoroethylene (PTFE), poly (fluoride vinylidene) (PVdF), or polypropylene-polyethylene-polypropylene (PP / PE / PP).
• the separator is a separator made of PP or PP / PE / PP (for example, a separator developed by Celgard MC ) or a cellulose separator (for example, a separator prepared according to the present method or a separator paper sold by Nippon Kodoshi Corporation).
• the separator is a cellulosic separator produced by filtering an aqueous mixture comprising cellulose fibers directly onto the rich electrochemically active material side of the self-supporting electrode.
• the electrolyte is usually chosen for its compatibility with the different elements of the electrochemical cell. Any type of electrolyte is envisioned, for example, liquid, gel or solid electrolytes.
• the electrolyte may be a liquid electrolyte comprising a lithium salt in a solvent.
• the electrolyte may be a gel electrolyte comprising a lithium salt in a solvent and / or a solvating polymer.
• the electrolyte may be a solid polymer electrolyte comprising a lithium salt in a solvating polymer.
• Non-limiting examples of lithium salts may include lithium hexafluorophosphate (LiPF 6 ), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium bis (fluorosulfonyl) imide (LiFSI), 2-trifluoromethyl-4 Lithium 5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), bis
• Lithium tetrafluoroborate LiBF 4 ), lithium bis (oxalato) borate (LiBOB), lithium nitrate (L1NO 3 ), lithium chloride (LiCl), bromide of lithium (LiBr), lithium fluoride (LiF), lithium perchlorate (UCIO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium trifluoromethanesulfonate (USO 3 CF 3 ) (LiTf), fluoroalkylphosphate of lithium lithium Li [PF 3 (CF 2 CF 3 ) 3 ] (LiFAP), lithium tetrakis (trifluoroacetoxy) borate Li [B (OCOCF 3 ) 4 ] (LiTFAB), bis [1,2-benzenediolato (2-) -0.0 '] lithium borate Li [B (C 6 C> 2 ) 2 ] (LBBB) and combinations thereof.
• the lithium salt is lithium
• the solvent is a non-aqueous solvent.
• non-aqueous solvents may include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC); acyclic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl and ethyl carbonate (EMC), and dipropyl carbonate (DPC); lactones such as g-butyrolactone (g-BL) and ⁇ -valerolactone (g-VL); acyclic ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), trimethoxymethane, and ethoxymethoxyethane (EME); cyclic ethers such as 2-methyltetrahydrofuran, 1,3-dioxolane, and derivatives thereof; amides such as formamide, acetamide,
• the present technology relates to a battery comprising at least one electrochemical cell as defined herein.
• the battery is a lithium-ion battery.
• the present technology relates to fully organic batteries comprising, for example, a self-supporting organic positive electrode and a self-supporting organic negative electrode.
• the fully organic battery comprises a self-supporting positive electrode comprising PTCDA and a self-supporting negative electrode comprising graphite.
• Fully organic (non-transition metal) batteries including a positive self-supporting electrode with PTCDA and a self-supporting negative electrode with graphite were prepared and electrochemically tested. These fully organic batteries (PTCDA / graphite) include organic redox molecules and biodegradable components. The present technology thus demonstrates the concept of inexpensive and biodegradable batteries. According to a sixth aspect, the present technology relates to the recycling of self-supporting electrodes as defined here using an essentially ecological process. A battery based on recycled materials is also considered here. EXAMPLES
• Sodra TM black R pulp fibers comprise unmodified cellulose fibers having a length in the range of 2.05 to 2.25 mm.
• VGCFs vapor-phase carbon fibers
• CNTs carbon nanotubes
• Denka MC Denka MC
• graphite graphite
• carbon is used in the procedure below to refer to one or other of these materials. 5 g of carbon were dispersed in 200 ml of an aqueous solution of sulfuric acid (H 2 SO 4 )
• the mixture was vacuum filtered using a Buchner type fitting and a nylon filter with a pore size of 0.22 ⁇ m.
• the modified particle powder thus obtained was then washed successively with N, N-dimethylformamide (DMF) and acetone. Finally, the modified C-LFP particle powder was dried under vacuum at 100 ° C for at least one day before use.
• DMF N, N-dimethylformamide
• the self-supporting electrodes were prepared as illustrated in FIG. 1.
• a volume of the aqueous mixture comprising cellulose fibers as described in Example 1 (a) corresponding to about 30 mg of cellulose fibers was added in a beaker.
• 10 mg of unmodified VGCF carbon fibers, or VGCFS-SO 3 H or VGCFs-COOH, as described in Example 1 (b) were then added to the beaker and dispersed in the aqueous mixture comprising cellulose fibers to obtain a first aqueous dispersion.
• the first aqueous dispersion was then stirred using an ultrasonic rod.
• VGCFS-SO 3 H and VGCFs-COOH-grafted VGCFs powders were instantly solubilized in the aqueous mixture while the commercial unmodified VGCFs carbon fibers took at least 10 minutes to solubilize.
• the first The aqueous dispersion was filtered using a Buchner type fitting and a nylon filter membrane having pore size of 0.22 ⁇ m and a flexible film was obtained (see FIG. )).
• the electron-conductive material-rich side of the resulting film can serve as a current collector.
• the other side of the resulting film is a rich cellulose fiber side (see Figure 2 (B)).
• the rich side of electronically conductive material faces the filter membrane during filtration of the mixture.
• the resulting film was then dried for 10 minutes.
• a second modified or unmodified electronic conductive material (VGCFs, Denka MC , and modified or unmodified NTCs, or combinations thereof) were then added to the aqueous dispersion.
• VGCFs grafted hydrophilic carbons and LiFePC> 4 particles coated with hydrophilic grafted carbons were more readily and rapidly dispersed in water.
• the aqueous dispersion was then stirred, poured directly onto the previously prepared film in the Buchner assembly and filtered to obtain a self-supporting electrode on the filter membrane.
• the self-supporting electrode was then peeled off from the filter membrane.
• the self-supporting electrode was then calendered at room temperature, at 50 ° C or at 80 ° C.
• FIG. 3 shows an LFP electrode as prepared in this example.
• Figure 3 (A) shows the rich side of electronically conductive material that remains bright whereas
• Figure 3 (B) shows the electrochemically active material (LFP) filling the pores of the fiber-rich side of cellulose (opposite the rich VGCFs side). ).
• Figure 3 (C) shows that the film remained intact and strong even after punching a small electrode.
• a paper separator can be prepared directly on the self-supporting electrode.
• a volume of an aqueous mixture comprising cellulose fibers prepared according to Example 1 (a) and corresponding to about 30 mg of cellulose fibers is filtered directly on the rich side of electrochemically active material of the self-supporting electrode before the take-off step of the self-supporting electrode of the filter membrane.
• Fig. 3 (D) shows a film comprising a self-supporting electrode and a separator as herein defined comprising a rich VGCFs side serving as a current collector, an integrated LFP electrode and a paper separator.
• the films as described in Example 1 (d) had a thickness of about 100 ⁇ m.
• the calendering of freestanding films has reduced their thickness.
• an average decrease of 20 and 30% in thickness was observed when the self-supporting electrodes were calendered at a temperature of 50 and 80 ° C, respectively.
• the films were flexible, foldable, rollable and durable as shown in Figure 2.
• FIG. 3 (C) shows that punching an electrode in the self-supporting electrode film has not substantially affected the integrity.
• the electron-conductive material-rich side (FIG. 2 (A)) obtained during the first manufacturing step remained substantially unchanged after the filtration step of the mixture containing the electrochemically active material.
• the pores of the cellulose fiber-rich side were filled with the electrochemically active material and the second electronically conductive material during the second filtration step.
• the self-supporting electrode obtained consists of a solid film based on cellulose having two surfaces.
• One of the two surfaces mainly comprises the first electronically conductive material and the other surface mainly comprises the electrochemically active material and the second electronically conductive material.
• Example 1 (d) The method described in Example 1 (d) is very interesting because the metal current collectors are replaced by carbon serving as a current collector.
• the weight of the metal current collectors may, for example, be replaced by more cellulose or carbon fibers or both, to obtain a stronger film with a carbon content greater than that of a carbon fiber. extended film on a metal current collector.
• the electrochemically active material for example, LFP
• the binder and the electronically conductive material representing about 6% by weight
• the inactive aluminum foil represents 41% by weight of the total weight of the electrode.
• Example 1 (d) Another advantage of the process described in Example 1 (d) is that the amount of electrochemically active material can be fully known since it is weighed before being added to the beaker and filtered (see Figure 1). Therefore, depending on the configuration of the battery or the cathode / anode materials used, the amount of active material in mg / cm 2 in the self-supporting film can be relatively easily adapted.
• LR2032 button cell batteries with two electrodes were assembled with metallic lithium as a counter-electrode and as a reference electrode and a Celgard TM -3501 separator or a Kodoshi TM paper separator impregnated with a liquid electrolyte comprising LiPF 6 to 1 M in a mixture EC: DEC (3: 7 by volume).
• the potential was swept from the open circuit potential (OCP) to 4.2 V, followed by a reverse scan of 4.2 V at 2.0 V vs Li / Li + .
• the potential was swept from open circuit potential (OCP) to 4.0 V, followed by reverse sweep from 4.0 V to 2.0 V vs Li / Li + .
• the potential was swept from the open circuit potential (OCP) at 1.5 V followed by an inverted sweep from 1.5 V to 3.5 V vs Li / Li + .
• OCP open circuit potential
• the potential was swept from the open circuit potential (OCP) at 1.2 V followed by an inverted sweep of 1.2 V at 2.5 V vs Li / Li + .
• the charge and discharge cycles were performed in galvanostatic mode at different current densities between 2.0 and 4.0 V, between 1.5 to 3.5 V, between 0 to 1.5 V and between 1, 2 at 2.5 V vs Li / Li + respectively for LFP, PTCDA, graphite and LTO electrodes. Five cycles were recorded for each cycling rate ranging from C / 10 to 5C and the experiment was automatically started with two training cycles at C / 24.
• LFP / LTO electrochemical cells with LFP / LTO weight ratios ranging from 1 to about 0.85 were also tested between 1.0 and 2.5 V vs. LTO at different cycling rates of C / 24. at 5C. Long-term cycling tests at C / 10, C / 2, C and 2C cycling rates were also performed at different cycling rates for PTCDA / Li, graphite / Li, LTO / Li, LFP / electrochemical cells. LTO, LFP / LTO, as well as LFP / graphite and PTCDA / graphite batteries directly after two training cycles at C / 24.
• Pretrithiation of PTCDA cathodes was performed in button cells using negative lithium electrodes by discharging at C / 24 from the open circuit potential (OCP) up to 1.5 V vs. Li / Li + followed by a chronoamperometry experiment at a constant potential of 1.5 V with a duration of 3 hours.
• OCP open circuit potential
• the button cells were disassembled and the prelithied positive PTCDA electrodes were recovered for assembly with negative graphite electrodes.
• Electrochemical properties of the reference electrode stainless steel wedge alone
• the paper electrode made of cellulose fibers
• FIG. 3 (D) The integrated paper separators as described in Example 1 (e) deposited directly on the electrode film as shown in FIG. 3 (D) were also characterized by cyclic voltammetry in order to verify the influence of the separators in FIG. paper on electrochemical properties.
• Figure 5 shows the cyclic voltammograms obtained for a freestanding LFP electrode including an integrated paper separator (discontinuous line) compared to a freestanding LFP electrode with a Celgard TM separator (solid line).
• the cyclic voltammograms obtained showed that the integrated paper separator did not substantially negatively affect the electrochemical properties of the self-supporting LFP electrode, the polarizations (DE) of the two electrodes being similar.
• Figure 6 (A) shows the cyclic voltammetry results
• Figure 6 (B) shows the specific capacitance results recorded with three self-supporting LFP electrodes having the same charge of electrochemically active material and obtained by the same method.
• three different carbons were used, namely unmodified VGCFs (solid line), VGCFs-COOH (dashed line) and VGCFS-SO3H (dashed line).
• the cyclic voltammograms were similar.
• the specific capabilities shown in Figure 6 (B) show a substantial improvement in the electrochemical performance of self-supporting electrodes including modified carbon, which is particularly apparent at the cycling rates of 2C and 5C.
• the discharge capacities of the three freestanding LFP electrodes were similar and approximately 155 mAh.g 1 .
• the discharge capacity remained at about 140 mAh.g -1 for the two electrodes of LFP freestanding comprising modified VGCFs, while a capacity of about 120 mAh.g - 1 was obtained using unmodified VGCFs.
• This capacity corresponds to the discharge capacity obtained at a rate of 5C for the two modified self-supporting LFP electrodes.
• Improved electrochemical performance can be attributed to the hydrophilic nature of the substituents that would allow the carbon to better fill the porosity created by the cellulose fibers.
• Figure 7 shows photographs in (A) of the self-supporting LFP electrode comprising unmodified VGCF, and (B) of the self-supporting LFP electrode comprising VGCF-COOH.
• Figure 7 (B) shows that the cellulose fibers were visible on the surface of the electrode, giving a stronger film with the electrochemically active material and the second electronically conductive material trapped in the cellulose fibers.
• the initial discharge capacity was recovered when unmodified VGCFs and VGCFs-COOH were used, respectively.
• Figure 8 compares the specific capacity of self-supporting electrodes comprising different mixtures of modified carbons.
• Figure 8 (A) shows the results for a combination of VGCFs-COOH and Denka-COOH (squares) and the results for a combination of VGCFS-SO3H and Denka-SChH (triangles).
• Figure 8 (B) shows the results of a combination of VGCFs-COOH and NTCs-COOH (squares) and the results of a combination of VGCFS-SO3H and NTCS-SO3H (circles).
• Figure 9 (A) shows the cyclic voltammetry results and Figure 9 (B) the capacitance versus cycle number results of the same calendered electrode at a temperature of 25 ° C and a temperature of 50 ° C.
• Figure 9 (A) shows excellent reproducibility for the two freestanding LFP electrodes calendered at different temperatures.
• the thickness of the self-supporting electrode decreases with increasing calender temperature.
• a thickness of about 100 .mu.m was generally obtained at a calendering temperature of 25.degree. C.
• a thickness of about 80 .mu.m and about 70 .mu.m was obtained respectively with calendering temperatures of 50.degree. ° C and 80 ° C.
• the nature of the electronically conductive material does not seem to have a significant effect on the thickness after calendering, which seems to be rather influenced mainly by the amount of cellulose fibers used. vi.
• LTO LLTisO 3
• SEI solid-electrolyte interphase
• the LTO is referred to as a material having zero stress since it remains stable during the insertion and de-insertion of lithium ions (see Zaghib, K. et al., Journal of Power Sources, 248, (2014): 1050-1057). Similar to LFP, LTO is a relatively inexpensive material and therefore an ideal candidate for low cost BLIs.
• Capacities of approximately 120, 105 and 95 mAh.g -1 were obtained at a cycling speed of 5C respectively for LTO electrodes obtained with a combination of VGCFs-COOH and NTCs-COOH (circles), the control comprising VGCFs-COOH alone (squares) and a combination of VGCFs-COOH and Denka MC carbon -COOH (triangles). Similar results were obtained when the -aryl-COOH groups were replaced by -aryl-SOsH (not shown in Figure 12). As with the LFP electrode cycling result shown in Figure 8, the addition of Denka TM carbon decreased the electrochemical performance of the LTO electrodes.
• FIG. 13 shows the capacity retention over 300 charge and discharge cycles for two different LTO electrodes, one comprising VGCFs-COOH alone and the other comprising a combination of VGCFs-COOH and NTCs-COOH. Near 100% of the initial discharge capacity at C / 2 was retained after the 300th cycle. Thus, capacities of approximately 157 and 150 mAh.g 1 were obtained for several hundred cycles at C / 2 when the electrode respectively comprised a combination of VGCFs-COOH and NTCs-COOH (circles) and VGCFs-COOH. alone (squares). x. Preparation of complete BLIs including LFP and LTO electrodes
• Figure 14 shows the specific capacity of two LFP / LTO batteries with the same amount of electrochemically active material for both electrodes but with a different separator.
• the discharge capacities obtained were higher when a Kodoshi TM paper separator (circles) was used instead of a conventional Celgard TM separator (squares).
• An increase of 10 mAh.g -1 was thus obtained for the battery entirely made of paper for each cycling speed varying from C / 24 to 2C in comparison with the cell assembled with a Celgard TM separator.
• 100 and 15 mAh.g -1 were obtained at 5C respectively for the battery using the Celgard TM separator and the paper separator.
• the improved electrochemical performance achieved with a paper separator could reduce the price of energy storage devices by replacing the Celgard TM separator with a paper separator.
• g 1 (star) were obtained when the films comprising 50 mg of LFP and LTO and 60 mg of LFP and LTO were respectively used. The same behavior was observed at 5C since mAh.g 115 1, 105 1 and 95 mAh.g mAh.g 1 were obtained respectively for the electrode films containing 40, 50 and 60 mg of electrochemically active material. xiii. Effect of the separator on long-term cycling experiments on complete BLIs including freestanding LFP and LTO electrodes
• Figure 16 (A) shows the retention capacity retention over 200 charge and discharge cycles for the same battery composition, but assembled with Celgard TM (square) and Kodoshi TM (circle) separators. As shown in Figure 16 (A), using a Kodoshi TM paper separator has increased specific capabilities. About 140 and about 130 mAh.g 1 were obtained for the first cycle at C / 2, respectively, when a paper separator and a Celgard TM separator were used. After 200 cycles, about 92% of the initial discharge capacity was recovered.
• Figure 16 (A) shows that the paper separator did not significantly improve capacity retention although the specific capacities remained higher. In both cases, a gradual loss of capacity during cycling was observed, which can be attributed to the LFP. Similar observations have been reported for electrodes made with submicron LFP plates (see Yang, XF et al., ChemSusChem, (2014) 7 (6), 1618-1622) and with reduced-size LFP particles cycled to 1C (Lux, SF et al., Journal of the Electrochemical Society (2010) 157.3, A320-A325). xiv. Long-Term Cycling Experiments on Complete BLIs Including Free-Standing LFP and LTO Electrodes and Kodoshi TM Paper Separators
• FIG 18 shows results of cyclic voltammetry and specific capacitance for self-supporting PTCDA electrodes with metallic lithium as counter-electrode and reference electrode.
• Figure 18 (A) the cyclic voltammetry results revealed that an increase in the mass of PTCDA in the self-supporting electrode causes an increase in polarization although the intensity of the oxidation-reduction peak increases slightly over time. the voltamogram. This behavior was confirmed by the specific capacity results as a function of the number of cycles (see Figure 18 (B)).
• Figure 19 shows the discharge capacity and coulombic efficiency results as a function of the number of cycles over 100 charge and discharge cycles for the same self-supporting PTCDA electrode composition, with the exception of the composition of the second material electronic conductor.
• Figure 19 (A) shows the results for a PTCDA electrode self-supporting comprising VGCFs-COOH as the second electronically conductive material and Fig. 19 (B) for the same self-supporting PTCDA electrode composition but comprising a mixture of VGCFS-SO3FI with a small amount of NTCS-SO3FI.
• modified NTCs significantly increased the specific surface area of the negative composite electrode and thus led to further degradation of the electrolyte and degradation of the lithium metal negative electrode.
• the higher electronic conductivity of the self-supporting film comprising modified CNTs provides better stability during cycling and allows to deliver an additional 75 mAh.g 1 compared to an electrode without modified NTCs. A progressive loss of capacity during cycling was observed for both electrodes, the latter being greater for the negative composite electrode without NTCs.
• Figure 23 (A) shows long cycling experiments for two graphite electrodes with different charges (30 and 40 mg of active material).
• the decrease in capacity may be related to the strength of the self-supporting film.
• the resistance of the film may be proportional to the amount of graphite used in the manufacture of said self-supporting film.
• the initial discharge capacity at C / 10 was about 380 mAh.g 1, which is substantially close to the theoretical capacity of graphite.
• the loss of capacity during the cycle was also less pronounced for free-standing electrodes comprising 30 mg of graphite than for self-supporting electrodes comprising 40 mg of graphite.
• Figure 23 (B) shows the cycling of three electrodes prepared with aryl-SOsH modified graphite.
• the discharge capacity for Similar loads of active material were significantly higher for the self-supporting graphite electrodes modified with SO 3 H groups than for the unmodified graphite self-supporting electrodes.
• a discharge capacity of 335 and 405 mAh.g 1 were obtained for the first discharge at C / 10 respectively for a self-supporting electrode comprising 40 mg of graphite and for a self-supporting electrode comprising 40 mg of graphite-SO 3 H.
• Increasing the active ingredient load up to 50 mg has improved cyclability and specific capacity.
• the -SO3H groups attached to the carbon surface increase the total capacity of the battery. These groups may, for example, contribute to the storage of lithium and the increase of the ionic conductivity. As shown in Figure 23, the coulombic efficiency was slightly lower in the first cycle at C / 24 when the modified graphite was used. xx /. Electrochemical properties of complete BLIs including self-supporting LF P and graphite electrodes
• Fully organic (no transition metal) PTC DA / graphite BLIs including self-supporting PTCDA and graphite electrodes, were prepared and electrochemically tested.
• Fully organic PTCDA / graphite BLIs including organic redox molecules and biodegradable components. These fully organic PTCDA / graphite BLIs demonstrate the concept of inexpensive and biodegradable batteries.
• FIG. 25 (A) shows the first discharge up to 1.5 V vs Li / Li + for three PTCDA / Li batteries comprising 50 and 60 mg of electrochemically active material for the cathode.
• the potential was maintained at 1.5 V for 3 hours (see Figure 25 (B)).
• the button cells were then disassembled and the prelithied self-supporting PTCDA electrodes were recovered for assembly with self-supporting graphite electrodes.
• Figure 26 shows the results of the first charge and discharge obtained at a constant current of C / 24 recorded between 1, 5 and 3.5 V vs graphite for two BLIs PTCDA pre-ligated / graphite. Due to the formation of an SEI on the negative graphite electrode, the specific capacity of the first charge was greater than the theoretical capacity of 137 mAh.g 1 for the PTCDA and reached approximately 160 mAh.g 1 . When the BLI was unloaded, a small amount of lithium was possibly irreversibly consumed by the graphite and capacities of only 104 and 108 mAh.g -1 were obtained respectively for the positive electrodes including 50 mg PTCDA and 60 mg of PTCDA.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Inorganic Chemistry (AREA)
• Composite Materials (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Secondary Cells (AREA)
• Cell Electrode Carriers And Collectors (AREA)
• Cell Separators (AREA)

Priority Applications (7)

Applications Claiming Priority (4)

Related Child Applications (2)

Publications (1)

Family

ID=68541094

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (8)

Citations (3)

Family Cites Families (11)

• 2019
  • 2019-05-15 CN CN201980032211.4A patent/CN112219299B/zh active Active
  • 2019-05-15 US US17/048,717 patent/US11811068B2/en active Active
  • 2019-05-15 EP EP19802496.0A patent/EP3794661B1/fr active Active
  • 2019-05-15 WO PCT/CA2019/050657 patent/WO2019218067A1/fr not_active Ceased
  • 2019-05-15 KR KR1020207034427A patent/KR20210006925A/ko not_active Ceased
  • 2019-05-15 JP JP2020563789A patent/JP7431175B2/ja active Active
• 2023
  • 2023-10-20 US US18/491,279 patent/US12603299B2/en active Active

Patent Citations (3)

Non-Patent Citations (21)

Also Published As

Similar Documents

Legal Events