WO2019005411A1 - Électrode pour une source d'énergie électrochimique et source d'énergie électrochimique comprenant ladite électrode - Google Patents

Électrode pour une source d'énergie électrochimique et source d'énergie électrochimique comprenant ladite électrode Download PDF

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WO2019005411A1
WO2019005411A1 PCT/US2018/035280 US2018035280W WO2019005411A1 WO 2019005411 A1 WO2019005411 A1 WO 2019005411A1 US 2018035280 W US2018035280 W US 2018035280W WO 2019005411 A1 WO2019005411 A1 WO 2019005411A1
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electrode
electrically conductive
electrode active
active material
polymer
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PCT/US2018/035280
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English (en)
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Semyon Kogan
Benjamin Joseph YURKOVICH
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Powermers Inc.
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    • H—ELECTRICITY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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    • 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
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    • 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
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    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
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    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
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    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
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    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
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    • 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
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    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • 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 present invention relates to electrochemical power sources and can be used to produce various electrochemical energy storage devices, more specifically, electrochemical capacitors, lithium primary batteries and lithium-ion batteries with high specific energy and high energy density.
  • Electrochemical power sources provide a very important link between the primary source of electrical energy and its actual use. They store energy in various forms that can be converted to electrical energy and transferred to an external electric circuit for further use when needed. EPSs find application in multiple sectors including transportation, electronics, aerospace, biomedical, and others. As a critical enabling technology for a variety of industry sectors, the performance of EPSs needs to be constantly improved to meet growing industry demands. Main performance parameters of an EPS include high energy and power density, long cycle life, safety, reliability, and environmental compatibility.
  • electrochemical capacitors are based on the electric double layer mechanism or Faradaic mechanism for energy storage.
  • Lithium-ion batteries a typical example of secondary batteries, rely on the lithium ions intercalation/deintercalation mechanism.
  • An electrode is a key component of any electrochemical energy power source, and its properties greatly affect the performance of an EPS.
  • the gravimetric energy density and volumetric energy density of an EPS depend on the gravimetric and volumetric capacities of the electrode, respectively.
  • the power density of an EPS depends on the rate at which the electrode can be charged and discharged.
  • the cycle life depends of the EPS depends on the chemical and electrochemical stability of all electrode components during charge and discharge.
  • the electrode active material is the main component of the electrode that participates in electrochemical reactions at the electrode. Electrode active materials are usually manufactured in the form of micron-size particles. For certain materials, these particles are formed by smaller size primary particles. The efficiency of electrode active material functioning largely depends on the availability of all particles, including primary particles, to participate in the electrochemical reactions at the electrode.
  • An example of an electrode active material for use in electrochemical capacitors is activated carbon.
  • Examples of electrode active materials for use in secondary batteries, in particular lithium-ion batteries include lithium insertion materials such as graphite, lithium transition metal oxides and phosphates, for example, lithium iron phosphate.
  • Electrode active material particles don't possess high electric conductivity whereas the electrode for an EPS needs to be highly conductive to be able to charge and discharge maximum achievable capacity at high rates.
  • a conductive additive is introduced into the electrode composition.
  • the conductive additive is usually introduced in the form of particles that electrically connect particles of active materials to each other and to the substrate (a current collector), which ensures a continuous flow of electrons through the electrode and participation of active material particles in the electrochemical reactions at the electrode.
  • the conventional conductive additive is generally formed of a material with high electrical conductivity, for example, carbonaceous materials such as, for example, carbon black.
  • electrode active material and a conductive additive need to be coated onto a certain substrate, which often also serves as a current collector.
  • substrate include aluminum foil, carbon-coated aluminum foil, copper foil, copper mesh, stainless steel mesh.
  • electrode active material particles as well as particles of a conductive additive usually don't have good adhesion to each other and to the substrate they require a binder to form a mechanically stable layer on the surface of the substrate.
  • Conventional binders used to make electrodes for EPSs are usually chemically and electrochemically inert polymers that have good adhesion to an electrode support and to the particles of the electrode active material and the conductive additive.
  • conventional binders include polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polyisobutene etc.
  • the electrode active layer comprising active material particles, a binder, and a conductive additive should have a sufficiently porous structure to allow for a continuous and free flow of electrolyte ions through the electrode. All active material particles should be in contact with electrolyte of an EPS to effectively participate in electrochemical reactions at the electrode.
  • each particle of the electrode active material should be electronically and ionically connected to the electrode substrate, which often serves a current collector, and to the electrolyte of the EPS, respectively.
  • a said conventional binder nor a said conventional conductive additive participates in the reversible electrochemical reactions at the electrode so they don't contribute to the EPS electrode capacity. For that reason, they are often called deadweight materials. As the total amount of deadweight materials often reaches and even exceeds 10 % of the electrode active layer weight (and volume), the electrode specific capacity (both per unit weight and unit volume) is reduced rather dramatically as compared to the theoretical limits for a particular electrode active material; -
  • the said binder usually doesn't possess conductive properties whereas the said conductive additive usually doesn't possess binding properties, which requires the addition of both types of materials to the electrode active layer in amounts sufficient for proper electrode functioning.
  • the relative amount of electrode active material needs to be reduced, which results in the reduction of the electrode specific capacity;
  • Particles of a conventional binder and a conventional conductive additive tend to aggregate and are unevenly distributed inside the electrode active layer, which hinders electron and ion transport within the electrode.
  • particles of a conductive additive can be too large to penetrate into the aggregates of primary particles of an active material and form an effective electric contact with them. As a result, some particles of active material become isolated from the continuous electron and electrolyte flow within the electrode and do not participate in electrochemical reactions thus reducing the electrode specific capacity;
  • a conductive additive is usually used in the form of particles, which limits the surface area of a mechanical contact between the active material particle and the particle of the conductive additive and adds a contact resistance to the electrode impedance thus diminishing electrical conductivity of the electrode active layer, which results in the reduced charge and discharge rates if the conductive additive is introduced in the insufficient amount;
  • lithium-ion batteries comprising high voltage material-based cathodes (cathodes comprising such active materials is for example lithium nickel manganese cobalt oxide (NMC) or lithium nickel cobalt aluminum oxide (NCA))
  • NMC lithium nickel manganese cobalt oxide
  • NCA lithium nickel cobalt aluminum oxide
  • the above features of conventional EPSs' electrodes limit the ability of known EPSs to meet the industry demand. Therefore, there is still a great need for improved EPSs, especially in terms of high specific energy and energy density.
  • the present invention addresses the problem of creating electrodes for EPSs with improved performance, in particular, higher gravimetric and volumetric capacity, which in turn, would allow creating an EPS having improved specific energy (and energy density).
  • the present invention provides an electrode for an electrochemical power source, said electrode comprising an electrode active layer coated onto an electrically conductive substrate, wherein the said electrode active layer comprises particles of electrode active material bound to each other and to the electrically conductive substrate by an electrically conductive polymer, which comprises monomer units of at least a tetradentate N 2 0 2 Schiff base transition metal complex.
  • polymer refers to a material comprising two or more repetitive monomer units. Also, the term “polymer” refers to the entire polymer or any fraction of the polymer.
  • the said electrically conductive polymer provides the following advantages:
  • the said polymer possesses binding properties with respect to electrode components so it can effectively bind particles of electrode active material to each other and to the electrode substrate. In other words, it can replace most or preferably all of a conventional binder in the electrode while providing mechanical stability of the electrode; - The said polymer also has sufficiently high electrical conductivity so when it binds particles of electrode active material to each other and to the electrode substrate it also creates efficient pathways for the electron transport. In other words, it can replace most or preferably all of a conventional conductive additive in the electrode while providing sufficient rate capability of the electrode;
  • the said polymer is an electrochemically active material so it participates in the reversible electrochemical reactions at the electrode, i.e. reversibly stores charge.
  • the electrode the gravimetric capacity is increased as compared to conventional electrodes;
  • the thickness of the electrode active layer at least remains the same.
  • said electrically conductive polymer is an electrochemically active material, which participates in the electrochemical reactions at the electrode and reversibly stores additional charge, the electrode volumetric capacity is increased as compared to conventional electrodes;
  • the said polymer performs both conductive and binding functions, in certain types of electrodes it can be used in a lower amount as compared to the total amount of a conductive additive and a binder in a conventional electrode.
  • the relative amount of electrode active material in the electrode active layer can be increased as compared to conventional electrodes, which also results in the increase in the electrode specific capacity;
  • the said polymer is a three-dimensional (3D) network, which possesses high electronic conductivity and is ideally permeable for an electrolyte of an EPS.
  • the polymer is evenly distributed inside the electrode active layer and also assists in achieving a uniform distribution of electrode active material particles inside the electrode active layer.
  • Polymer chains are small enough to penetrate into the aggregates of primary particles of an electrode active material and form an effective electric contact with them. As a result, nearly all particles of electrode active material become involved in a continuous electron and electrolyte flow within the electrode and participate in electrochemical reactions thus increasing the electrode specific capacity;
  • the said polymer forms a more efficient electric contact with electrode active material particles as the polymer essentially grows on the surface of those particles.
  • the electrical conductivity of the electrode active layer is improved, which results in the improved rate capability of the electrode;
  • the said polymer is electrochemically, chemically and thermally stable, which ensures chemical, electrochemical, and thermal stability of the electrode comprising such a polymer and high cycle life of the electrode and an EPS.
  • the electrically conductive substrate serves as a carrier for an electrode active layer and provides electrical connection between the electrode active layer and other electrically conductive components of an EPS.
  • an electrically conductive substrate include foils made of aluminum, nickel, and combinations thereof.
  • Non-limiting examples of an electrically conductive substrate also include foils made of copper, gold, a copper alloy, or a combination thereof. Said foils can be further coated with carbon to decrease interfacial resistance at the electrode active layer/electrically conductive substrate interface.
  • Non-limiting examples of an electrically conductive substrate also include meshes made of stainless steel, aluminum, nickel, and combinations thereof.
  • Non-limiting examples of an electrically conductive substrate also include meshes made of copper, gold, a copper alloy, or a combination thereof.
  • Non-limiting examples of an electrically conductive substrate also include carbonaceous materials and metal-coated carbonaceous materials.
  • a person of ordinary skill in the art would understand that the choice of material for an electrically conductive substrate should be based on the composition and application requirements for the electrode and the EPS according to the present invention (for example, on the chemical composition of the electrode active material, whether the electrode is used as a cathode or the anode, etc.).
  • the electrode active material is the material that can reversibly store electric charge, preferably by participating in electrochemical reactions at the electrode.
  • the electrode active material may include any conventional electrode active materials currently used in electrodes for electrochemical power sources.
  • an electrode active material may include metal oxides, activated carbon, carbon fiber cloth, petroleum coke, graphite, other carbonaceous materials, and a mixture thereof.
  • an electrode active material may include a compound capable of reversible intercalation and deintercalation of lithium, for example, lithium manganese-based oxides, lithium cobalt-based oxides, lithium nickel cobalt manganese-based oxides, lithium nickel cobalt aluminium-based oxides, and olivine-type lithium iron phosphates or a mixture thereof.
  • the electrode active material is not limited thereto and any electrode active material used in the related art may be used.
  • Electrode active material particles may optionally be coated with a conductive surface layer to improve electronic and/or ionic conductivity of pristine material, which ultimately leads to an improved performance of the electrode active materials at high rates.
  • a conductive surface layer may include carbon black, graphitic carbon, polyaniline, polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene), poly(3,4- ethylenedioxythiophene)-poly(styrenesulfonate), and mixtures thereof.
  • the material for said conductive surface layer is not limited thereto and any conductive material known in the art may be used for a conductive surface layer if it will lead to an improvement in the electronic and/or ionic conductivity of pristine electrode active material.
  • Electrode active material particles may optionally be coated with a protective surface layer to suppress side reactions on the surface of active material particles, which ultimately leads to an enhanced electrochemical performance of these electrode active materials and/or longer cycle life of electrodes comprising these materials.
  • a protective surface layer may include aluminum oxide, aluminum fluoride, ammonium fluoride, silicon oxide, magnesium oxide, zinc oxide, lithium carbonate, and mixtures thereof.
  • a person of ordinary skill in the art would understand that the material for said protective surface layer is not limited thereto and any material known in the art may be used for a protective surface layer if it will lead to an enhanced electrochemical performance of pristine electrode active materials and/or longer cycle life of electrodes comprising these materials.
  • the electrically conductive polymer comprising monomer units of at least a tetradentate N 2 0 2 Schiff base transition metal complex preferably functions as an electrically conductive binder capable of reversibly storing charge by participating in electrochemical reactions at the electrode.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may include a compound of [M(R,R'-Salen)] type represented by the following structural formula:
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • Salen is a residue of bis(salicylaldehyde)ethylenediamine in the Schiff base;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may include a compound of [M(R,R comptural formula:
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • Saltmen is a residue of bis(salicylaldehyde)tetramethylethylenediamine in the Schiff base;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may include a compound of [M(R,R'-Salphen)] type represented by the following structural formula:
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • Salphen is a residue of bis(salicylaldehyde)-o-phenylenediamine in the Schiff base;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • R substituents in the Schiff bases of said compounds of [M(R,R'-Salen)]-, [M(R,R'-Saltmen)]-, [M(R,R'-Salphen)]-type are not limited thereto, and any functional groups that would enable desired functionality for the monomers (and the polymer comprising said monomers) and not prevent said monomers from polymerization may be used as R substituents.
  • said electrically conductive polymer may comprise monomer units of the same chemical structure and/or composition.
  • such electrically conductive polymer is a homopolymer.
  • said electrically conductive polymer may also comprise monomer units of a thiophene, 3-alkylthiophenes, 3,4-dialkylthiophenes, 3,4-ethylenedioxythiophene (EDOT) and combinations thereof.
  • EDOT 3,4-ethylenedioxythiophene
  • Such thiophene-type monomer units included in the polymer composition help improve the electrical conductivity of the polymer, which results in the increase in the rate capability of the electrode and improvement in the specific power and power density of an EPS containing said cathode.
  • said electrically conductive polymer may comprise monomer units of different chemical structure and/or composition.
  • said electrically conductive polymer comprising monomer units of different chemical structure and/or composition is a copolymer.
  • said electrically conductive polymer comprising monomer units of different chemical structure and/or composition is a mixture of polymers (homopolymers and/or copolymers).
  • said electrically conductive polymer may also comprise monomer units of ethylene oxide.
  • the presence of such repetitive monomer units in the polymer composition makes the polymer able to intrinsically conduct ions, in particular, lithium ions in lithium-ion containing electrolytes used, for example, in lithium-ion batteries.
  • the polymer becomes not only electronically but also ionically conductive, and able to improve not only electron flow but also the flow of ions through the electrode, which results in the increased rate capability of the electrode and improvement in the specific power and power density of an EPS containing said cathode.
  • the electrically conductive polymer according to various embodiments of the present invention may be obtained from corresponding monomers using, for example, oxidative polymerization methods.
  • oxidative polymerization methods include oxidative electrochemical polymerization and oxidative chemical polymerization.
  • Oxidative electrochemical polymerization may be accomplished, for example, by polarizing an electrically conductive substrate (electrode) in the electrolyte containing monomers at least until the electrode potential reaches the polymerization potential. At that, the amount of the synthesized polymer depends on the amount of time the electrode is polarized at the polymerization potential.
  • the electrode can be polarized using techniques known to those skilled in the art.
  • Non-limiting examples of such techniques include cyclic voltammetry, galvanostatic charge, constant potential polarization, pulse potential polarization, etc.
  • Oxidative chemical polymerization may be accomplished, for example, by adding an oxidative agent strong enough to cause monomer oxidation to a monomer-containing mixture.
  • Non-limiting examples of such an oxidative agent include salts comprising a Fe +3 , NO + , or Ag + cation and a BF 4 " or PF 6 " anion.
  • Non-limiting examples of such an oxidative agent also include salts comprising an NH 4 + , K + or Na + cation and a persulfate anion or a chlorate anion.
  • the polymerization methods are not limited thereto and any polymerization methods that would produce an electrically conductive polymer comprising monomer units of at least a tetradentate N 2 0 2 Schiff base transition metal complex may be used.
  • Said electrically conductive polymer may be synthesized prior to, at the same time, or after the electrode active material is coated onto the electrically conductive substrate to form an active layer of the electrode according to various embodiments of the present invention.
  • the electrode may be manufactured so that the electrode active layer comprises an electrically conductive polymer in a neutral (non-charged) form.
  • the electrode active layer comprises an electrically conductive polymer in a neutral (non-charged) form.
  • the polymer is electrochemically oxidized during charging of the cathode.
  • the positive charge formed on the polymer is compensated by anions of the electrolyte of the EPS containing said cathode.
  • the polymer is reversibly converted back into the neutral form upon discharging the cathode, which is accompanied by the release of charge- compensating anions.
  • When such polymer is used as a component of the anode active layer it is electrochemically reduced during charging of the anode.
  • the negative charge formed on the polymer is compensated by cations of the electrolyte of the EPS containing said anode.
  • the polymer is reversibly converted back into the neutral form upon discharging the anode.
  • the electrode may be manufactured so that the electrode active layer comprises an electrically conductive polymer in a charged form, wherein the charge on the polymer is stabilized by counterions.
  • the electrode active layer comprises an electrically conductive polymer in a charged form, wherein the charge on the polymer is stabilized by counterions.
  • a positively charged polymer stabilized by anions is a component of the cathode active layer it facilitates the electrochemical oxidation of the cathode active material during first charge of the cathode.
  • the polymer is converted into a neutral form upon discharging of the cathode, which is accompanied by the release of charge-compensating anions into the electrolyte.
  • a negatively charged polymer stabilized by cations When a negatively charged polymer stabilized by cations is used as a component of the anode active layer it facilitates the electrochemical reduction of the anode active material during first charge of the anode.
  • the polymer is converted into a neutral form upon discharging of the anode, which is accompanied by the release of charge-compensating cations into the electrolyte.
  • the aforementioned cations and anions should preferably comprise cations and anions of the electrolyte of the electrochemical power source containing the electrode comprising such polymer.
  • Using said polymer in an oxidized or a reduced form as an electrode component has an advantage of preventing possible issues of electrolyte depletion of ions during electrochemical charge-discharge of the electrode.
  • the electrode may be manufactured so that the electrode active layer comprises an electrically conductive polymer in a self-doped form.
  • the electrode active layer comprises an electrically conductive polymer in a self-doped form.
  • the electrode active layer may comprise electrode active material particles and an electrically conductive polymer in a neutral, an oxidized, a reduced, or a self-doped form, wherein said electrode active material particles and an electrically conductive polymer preferably have overlapping ranges of potentials for their electrochemical activity.
  • the charging and discharging potentials for the cathode active material should preferably be within the range of potentials for the polymer reversible oxidation whereas the charging and discharging potentials for the anode active material should preferably be within the range of potentials for the polymer reversible reduction. Otherwise, the electrical conductivity of the polymer may be too low to provide sufficient electrical conductivity between particles of electrode active material and between said particles and the electrode substrate.
  • the electrode may be manufactured so that the electrode active layer comprises an electrically conductive polymer in an oxidized form stabilized by non-mobile anions.
  • the electrode may be manufactured so that the electrode active layer comprises an electrically conductive polymer in a reduced form stabilized by non-mobile cations.
  • Such pre-doping of the polymer with non-mobile anions or cations increases its electrical conductivity, which allows to improve electrical contact between particles of electrode active material and between said particles and the electrode substrate, which results in higher rate capability of the electrode.
  • the polymer is initially in the oxidized or reduced form it cannot participate in the electrochemical reactions at the electrode. As a result, such polymer serves only as a binder and a conductive additive and does not contribute to the electrode capacity.
  • the electrically conductive polymer forms a coating on the surface of an electrode active material particle, in addition to connecting electrode active material particles to each other and to an electrically conductive substrate.
  • a coating increases the electrical contact surface area between particles, which results in the improved electrical conductivity of the electrode active layer and, hence, an improved rate capability of the electrode.
  • the electrode according to the present invention may optionally further comprise an additional binder and/or an additional conductive additive.
  • the additional binder helps improve mechanical stability of the electrode active layer and the adhesion of the electrode active layer to the electrically conductive substrate, thereby improving the mechanical stability of the electrode according to the present invention.
  • the additional binder include polyvinylidene fluoride (difluoride) (PVDF), polytetrafluoroethylene (PTFE), polyisobutene, styrene-butadiene rubber (SBR), carboxymethyl cellulose, polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, and hydroxypropyl cellulose or a mixture thereof.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • SBR styrene-butadiene rubber
  • carboxymethyl cellulose polyacrylic acid
  • polyvinyl alcohol polyvinyl pyrrolidone
  • hydroxypropyl cellulose or a mixture thereof hydroxypropyl cellulose or a mixture thereof.
  • the binder is
  • the additional conductive additive helps improve electrical conductivity of the electrode active layer, thereby improving conductivity and rate capability of the electrode according to the present invention.
  • the auxiliary conductive additive include carbon black, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon nanotubes, carbon fibers, metal powders and metal fibers.
  • the conductive agent is not limited thereto and any conductive agent known in the art may be used.
  • the electrode for an electrochemical power source according to the present invention may be manufactured via conventional methods known to those skilled in the art.
  • the electrically conductive polymer may be coated onto the electrically conductive substrate before, at the same time, or after the electrode active material is coated onto the electrically conductive substrate to form an active layer of the electrode according to various embodiments of the present invention.
  • an active layer of a conventional electrode for an electrochemical power source is essentially comprised of an electrode active material, a non-conductive binder and a non-adhesive conducting additive
  • the electrode according to the present invention can be manufactured merely by using an electrode active material and an electrically conductive polymer.
  • the manufacturing process for the electrode can be more simple and cost-effective by virtue of a simpler electrode design versus a conventional electrode for an EPS.
  • the present invention also provides an electrochemical power source comprising at least two electrodes, wherein at least one electrode is the electrode as disclosed above.
  • An electrochemical power source is any electrochemical device that store energy, which can be converted to an electrical energy, in particular, by means of electrochemical reactions at the electrodes.
  • Non-limiting examples of an electrochemical power source include primary batteries, secondary batteries, electrochemical capacitors, fuel cells, or the like.
  • an electrochemical power source also includes at least a separator and an electrolyte, and the choice of an electrolyte and a separator for an electrochemical power source should be based on the type of and application requirements to an EPS.
  • the electrochemical power source according to the present invention may be obtained by using conventional methods known to those skilled in the art.
  • the aforementioned EPS may be obtained by providing at least a cathode and an anode, wherein either of or both electrodes are manufactured according to the embodiments of the present invention, and also providing a separator, an electrolyte and a casing.
  • the separator may be placed between the cathode and the anode so that to completely prevent any electrical contact between them.
  • the resulting electrode "sandwich” may be placed into a casing, which is then filled with an electrolyte.
  • Fig. 1 schematically illustrates the design of a conventional electrode for use as a lithium-ion battery cathode (prior art);
  • Fig. 3 shows an SEM image of an active layer of a conventional electrode for use as a lithium-ion battery cathode (prior art);
  • FIG. 4 schematically illustrates the design of an electrode for use as a lithium-ion battery cathode according to present invention
  • Fig. 5 illustrates the structure of an active layer of an electrode for use as a lithium-ion battery cathode according to present invention
  • Fig. 6 shows an SEM image of an active layer of an electrode for use as a lithium-ion battery cathode according to present invention
  • Fig. 7 demonstrates charge-discharge curves of power sources according to Example 1 of the present invention.
  • Fig. 8 demonstrates charge-discharge curves of power sources according to Example 2 of the present invention.
  • Fig. 9 demonstrates charge-discharge curves of power sources according to Example 3 of the present invention.
  • the electrode active layer comprises lithium iron phosphate, LiFeP0 4 (LFP) as an electrode active material and an electrically conductive polymer comprising monomer units of at least a tetradentate N 2 0 2 Schiff base transition metal complex.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may be a compound of [M(R,R'-Salen)] type represented by the following structural formula:
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may be a compound of [M(R,R'-Saltmen)] type represented by the following structural formula:
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • Saltmen is a residue of bis(salicylaldehyde)tetramethylethylenediamine in the Schiff base;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • a tetradentate N 2 0 2 Schiff base transition metal complex may be a compound of [M(R,R'-Salphen)] type represented by the following structural
  • M is a transition metal selected from the group consisting of nickel, palladium, platinum, cobalt, copper, iron;
  • Salphen is a residue of bis(salicylaldehyde)-o-phenylenediamine in the Schiff base;
  • R is a substituent in the Schiff base selected from the group consisting of H, CH 3 O-, C 2 H 5 O-, HO-, -NO 2 , and -CH 3 ;
  • R' is a substituent in the Schiff base selected from the group consisting of H, and the halogens.
  • Said electrically conductive polymer may also comprise monomer units of a thiophene, 3-alkylthiophenes, 3,4-dialkylthiophenes, 3,4-ethylenedioxythiophene (EDOT), ethylene oxide or combinations thereof.
  • EDOT 3,4-ethylenedioxythiophene
  • Said electrically conductive polymer may be a homopolymer, a copolymer, or a mixture of polymers.
  • a conventional LFP-based electrode 1 (Fig. 1) comprises an electrode active layer 2 coated onto an electrically conductive substrate 3, wherein the electrode active layer 2 (see Fig. 2) comprises LFP particles 4, carbon black particles 5, and PVDF particles 6.
  • LFP particles 4 are coated with an ultrathin carbon layer 7.
  • carbon black particles 5 may form aggregates 8 so they are not able to provide electric contact to all LFP particles 4, including smaller primary LFP particles forming larger LFP particles.
  • PVDF particles 6 may also form aggregates 9 and hinder ionic transport inside the electrode active layer 2. As a result, the specific capacity of the electrode is reduced.
  • Fig. 3 shows the non-uniform morphology of a conventional LFP-based electrode containing unevenly distributed LFP-particles and large amorphous aggregates of carbon black and PVDF particles.
  • An LFP-based electrode 11 according to the present invention (Fig. 4) comprises an electrode active layer 12 coated onto an electrically conductive substrate 13, wherein the electrode active layer 12 (see Fig. 5) comprises LFP particles 14 bound to each other and to the electrically conductive substrate by an electrically conductive polymer 20 comprising monomer units of at least a tetradentate N 2 0 2 Schiff base transition metal complex. LFP particles 14 are coated with an ultrathin carbon layer 17.
  • the polymer 20 also forms a polymer coating 21 on the surface of a carbon layer 17.
  • the polymer 20, 21 forms a much less resistive electric contact with the LFP particles 14 than the electric contact of carbon particles 5 with LFP particles 4 (see Fig. 2) in a conventional electrode.
  • the polymer 20, 21 forms such efficient electric contact even with small primary particles forming larger LFP particles. That provides a participation of all LFP particles in the reversible electrochemical reactions at the electrode.
  • the electrically conductive substrate 13 can be made, for example, of a conductive carbon-coated aluminum foil (MTI Corporation).
  • the electrode active layer 12 can be coated onto the surface of the electrically conductive substrate 13, for example, by an electrochemical polymerization from a suspension containing LFP particles, at least a tetradentate N 2 0 2 Schiff base transition metal complex and an acetonitrile-based electrolyte.
  • An electrochemical polymerization of a tetradentate N 2 0 2 Schiff base transition metal complex on the surface of an electrically conductive substrate results in the formation of a polymer, which has a 3D structure composed of molecular stacks covalently bound to each other. Each stack is composed of monomer units of said complex bound to each other via donor-acceptor interactions between a metal center of one monomer unit and a ligand of another monomer unit. Said stacks are bound to each other by carbon-carbon bonds between monomer units of adjacent stacks.
  • This 3D-structure is mechanically, chemically, thermally, and electrochemically stable under conditions of a Li-ion battery functioning.
  • the polymer structure is sufficiently porous to be completely permeable for the electrolyte and support high rates of ion transport. The electron transport occurs along stacks as well as between them so the electron transport in the polymer is also essentially three-dimensional.
  • Fig. 6 shows an SEM image of an active layer of an electrode according to present invention This SEM image is taken at the same magnification as the SEM image shown in Fig. 3. As follows from the comparison of these SEM images, the morphology of an LFP-based electrode according to the present invention is significantly more uniform than the morphology of a conventional electrode.
  • Step 1 of the electrode preparation an electrode substrate was made by cutting a 1 ⁇ 2-inch disk from a piece of stainless steel mesh (AISI 316, 250 mesh) treated with 6M hydrochloric acid (HCI) for 10 minutes, rinsed with distilled water to remove traces of acid, and dried at 120°C for 1 hour. Such obtained disk was weighed. A thin aluminum terminal was spot welded to the disk.
  • AISI 316, 250 mesh stainless steel mesh
  • HCI hydrochloric acid
  • Step 2 a slurry was made by combining and carefully mixing 99.5 wt% LFP (MTI Corporation) and 0.5 wt% PVDF (MTI Corporation) (based on the total weight of LFP and PVDF) in N-Methyl-2-pyrrolidone (NMP) (purchased from Sigma-Aldrich).
  • NMP N-Methyl-2-pyrrolidone
  • 20 mg of the slurry was evenly coated onto one side of the electrode substrate using a spatula, followed by drying at 120°C for 4 hours.
  • Step 3 a poly-[Ni(CH 3 0-SalEn)] polymer was deposited onto the sample prepared in Step 2 by electrochemical polymerization of [Ni(CH 3 0-SalEn)] monomer in a one-compartment three-electrode electrochemical cell filled with a solution comprising 10 ml of acetonitrile, 48.1 mg of [Ni(CH 3 0-SalEn)], and 94 mg of LiBF 4 .
  • the sample prepared in Step 2 was used as a working electrode.
  • a piece of aluminum foil coated with an activated carbon-based layer was used as an auxiliary electrode.
  • the cell also included a non-aqueous Ag/Ag + reference electrode (MF 2062, BASi) having a potential of -300 mV vs. a standard silver/silver chloride reference electrode. Electrodes of the cell were connected to a Bio-Logic VSP potentiostat/galvanostat (Bio-Logic, SAS, France). 450 pulses of potential of + 1 .0 V vs. Ag/Ag + were applied to the working electrode, wherein the pulse duration was 1 s. Each pulse of potential was followed by 10 s at open circuit voltage (OCV) . After that, the working electrode was removed from the cell, carefully rinsed with acetonitrile, and dried at 120°C for 1 hour.
  • OCV open circuit voltage
  • the aluminum terminal was detached from the sample prepared in Step 3 to leave a 1 ⁇ 2-inch disk electrode comprising a stainless steel mesh substrate coated with an active layer comprising 88.5 wt% LFP, 0.5 wt% PVDF, and 1 1 .0 wt% poly-[Ni(CH 3 0-SalEn)] (based on the weight of the active layer).
  • a 1 ⁇ 2-inch disk electrode comprising a stainless steel mesh substrate coated with an active layer comprising 88.5 wt% LFP, 0.5 wt% PVDF, and 1 1 .0 wt% poly-[Ni(CH 3 0-SalEn)] (based on the weight of the active layer).
  • Such obtained electrode was weighed.
  • a CR-2032 type coin cell was assembled in a stainless steel case (MTI Corporation) using a provided cathode prepared as described above according to the present invention, an anode made of 450 ⁇ thick lithium foil, and a Cellgard 2500 separator.
  • the cell was filled with 50 ⁇ of electrolyte comprising 1 .0 M LiPF 6 solution in a mixed solvent of ethylene carbonate and diethyl carbonate in the volume ratio of 1 : 1 (purchased from ALDRICH) .
  • a comparative cell was fabricated in the same way as described above except that the sample prepared in Step 2 was used as a cathode.
  • the sample prepared in Step 2 had an aluminum terminal detached and was weighed prior to the cell assembling.
  • the comparative cathode was a 1 ⁇ 2-inch disk electrode comprising a stainless steel mesh substrate coated with an active layer comprising 99.5 wt% LFP and 0.5 wt% PVDF (based on the weight of the active layer).
  • Fig. 7 shows the resulting charge-discharge curves wherein the cell voltage is plotted against the specific capacity of the cell (per gram of the cathode active layer). The weight of the cathode active layer was calculated by subtracting the weight of the 1 ⁇ 2 inch stainless steel disk from the weight of the prepared electrode (for both provided and comparative electrodes). It can be observed from Fig. 7 that the specific discharge capacity (per gram of the cathode active layer) of the provided cell is about 2.5 times higher than that of the comparative cell.
  • a portion of the discharge curve of the provided cell between about 3.9 V and about 3.32 V corresponds to an electrochemical discharge of the poly-[Ni(CH 3 0-SaEn)] polymer (polymer reduction from the oxidized into a neutral state), which indicates that said polymer stores charge in the provided electrode.
  • the specific capacity of the comparative cell per gram of active material was calculated from the experimental data to be 48.5 mAh/g.
  • the specific capacity of the provided cell per gram of LFP was calculated to be 137 mAh/g.
  • the above numbers indicate that a more significant percentage of LFP particles take part in electrochemical reactions at the provided electrode vs. a comparative electrode, which does not contain a conductive additive. This, in turn, indicates that in the provided electrode, the poly-[Ni(CH 3 0-SaEn)] polymer provides electrical connection between particles of LFP and between them and the electrode substrate.
  • the poly-[Ni(CH 3 0-SaEn)] polymer performs 3 main functions: it serves as a binder, a conductive additive, and an electroactive charge storing material, which provides higher specific capacity of the power source comprising such electrode as a cathode versus a comparative power source comprising a polymer-free cathode.
  • Step 1 and Step 2 of the electrode preparation were the same as in Example 1 .
  • Step 3 a conductive polymer was deposited onto the sample prepared in Step 2 by electrochemical co-polymerization of [Co(CH 3 0-SalEn)] and 3,4-ethylenedioxythiophene (EDOT) in a one-compartment three-electrode electrochemical cell placed inside an argon-filled glove box.
  • the sample prepared in Step 2 was used as a working electrode.
  • a piece of aluminum foil coated with an activated carbon-based layer was used as an auxiliary electrode.
  • the cell also included a non-aqueous Ag/Ag + reference electrode (MF 2062, BASi) having a potential of -300 mV vs. a standard silver/silver chloride reference electrode.
  • MF 2062, BASi non-aqueous Ag/Ag + reference electrode having a potential of -300 mV vs. a standard silver/silver chloride reference electrode.
  • Electrodes of the cell were connected to a Bio-Logic VSP potentiostat/galvanostat (Bio-Logic, SAS, France).
  • the cell was first filled with 10 ml of an electrolyte comprising 0.1 M LiBF 4 solution in acetonitrile.
  • the working electrode was polarized at +750 mV vs. Ag/Ag + for 30 minutes. After that, the solution in the cell was replaced with a solution comprising 10 ml of acetonitrile, 48.1 mg of [Co(CH 3 0-SalEn)], 26 ⁇ of EDOT, and 94 mg of LiBF 4 .
  • 300 pulses of potential of +1 .2 V vs. Ag/Ag + were applied to the working electrode, wherein the pulse duration was 1 s. Each pulse of potential was followed by 10 s at OCV. After that, the working electrode was removed from the cell, carefully rinsed with acetonitrile, and dried at 120°C for 1 hour.
  • the aluminum terminal was detached from the sample prepared in Step 3 to leave a 1 ⁇ 2-inch disk electrode comprising a stainless steel mesh substrate coated with an active layer comprising 95.5 wt% LFP, 0.5 wt% PVDF, and 4.0 wt% polymer comprising monomer units of [Co(CH 3 0-SalEn)] and EDOT (based on the weight of the active layer).
  • a CR-2032 type coin cell was assembled in a stainless steel case (MTI Corporation) using a provided cathode prepared as described above, an anode made of 450 ⁇ thick lithium foil, and a Cellgard 2500 separator. The cell was filled with 50 ⁇ _ of electrolyte comprising 1 .0 M LiPF 6 solution in a mixed solvent of ethylene carbonate and diethyl carbonate in the volume ratio of 1 : 1 (purchased from ALDRICH) .
  • a comparative cell was fabricated in the same way as described above except the cathode was prepared using only Steps 1 and 2 of the above described procedure.
  • the slurry was made by combining and carefully mixing 90 wt% LFP, 5 wt% PVDF, and 5 wt% Super P carbon (purchased from TIMCAL) (based on the total weight of LFP, PVDF, and Super P carbon) in NMP, wherein the NMP weight was 3 times larger than the total weight of LFP, PVDF, and Super P carbon. 40 mg of such prepared slurry was coated onto the electrode substrate. Prior to assembling a cell, the sample prepared in Step 2 had an aluminum terminal detached and was weighed.
  • the comparative cathode was a 1 ⁇ 2-inch disk electrode comprising a stainless steel mesh substrate coated with an active layer comprising 90 wt% LFP, 5 wt% PVDF, and 5 wt% Super P carbon (based on the weight of the active layer).
  • Fig. 8 shows the resulting charge-discharge curves wherein the cell voltage is plotted against the specific capacity of the cell (per gram of the cathode active layer). The weight of the cathode active layer was calculated by subtracting the weight of the 1 ⁇ 2-inch stainless steel disk from the weight of the prepared electrode (for both provided and comparative electrodes). It can be observed from Fig.
  • a portion of the discharge curve of the provided cell between about 3.9 V and about 3.4 V corresponds to an electrochemical discharge of the polymer comprising monomer units of [Co(CH 3 0-SaEn)] and EDOT (polymer reduction from the oxidized into a neutral state), which indicates that said polymer stores charge in the provided electrode.
  • the specific capacity of the comparative cell per gram of active material was calculated from the experimental data to be 140 mAh/g.
  • the specific capacity of the provided cell per gram of LFP was calculated to be 139 mAh/g.
  • the above numbers indicate that about the same percentage of LFP particles takes part in electrochemical reactions at the provided electrode vs. a comparative electrode despite the fact that the provided electrode does not contain Super P carbon (a conductive additive) This, in turn, indicates that in the provided electrode, the polymer comprising monomer units of [Co(CH 3 0-SalEn)] and EDOT provides efficient electrical connection between particles of LFP and between them and the electrode substrate.
  • the active layer particles do not detach from the electrode substrate during electrode handling despite the fact that the active layer contains a very low amount of PVDF, which alone cannot provide mechanical stability to the electrode (as shown in Example 1).
  • the polymer comprising monomer units of [Co(CH 3 0-SalEn)] and EDOT performs a binding function with respect to LFP particles (binds them to each other and to the electrode substrate thus providing mechanical stability to the electrode).
  • the polymer comprising monomer units of [Co(CH 3 0-SalEn)] and EDOT performs 3 main functions: it serves as a binder, a conductive additive, and an electroactive charge storing material, which provides higher specific capacity of the power source comprising such electrode as a cathode versus a comparative power source comprising a polymer-free cathode.
  • Step 1 of the electrode preparation a 2 cm ⁇ 2 cm piece was cut from a commercially available conductive carbon-coated aluminum foil (MTI Corporation).
  • Step 2 an active layer was deposited onto a sample prepared in Step 1 . The deposition was accomplished in a one-compartment three-electrode electrochemical cell equipped with a magnetic stirrer. A sample prepared in Step 1 was used as a working electrode. The working electrode was positioned parallel to the cell bottom. A 2 cm ⁇ 2 cm piece of a conductive carbon-coated aluminum foil was used as an auxiliary electrode. The auxiliary electrode was positioned above the working electrode and parallel to it.
  • the cell also included a non-aqueous Ag/Ag + reference electrode (MF 2062, BASi) having a potential of -300 mV vs. a standard silver/silver chloride reference electrode. Electrodes of the cell were connected to a Bio-Logic VSP potentiostat/galvanostat (Bio-Logic, SAS, France). The cell was then filled with a suspension comprising 10 ml of acetonitrile, 1 1 mg of [Ni(CH 3 -SaEn)], 60 mg of LFP, and 94 mg of LiBF 4 . 30 pulses of potential of +0.6 V vs. Ag/Ag + were applied to the working electrode, wherein the pulse duration was 4 s.
  • MF 2062, BASi non-aqueous Ag/Ag + reference electrode having a potential of -300 mV vs. a standard silver/silver chloride reference electrode. Electrodes of the cell were connected to a Bio-Logic VSP potentiostat/galvano
  • Each pulse of potential was followed by 20 s at OCV.
  • the dispersion was stirred before the first pulse of potential and between pulses to cause an even distribution of LFP particles in the dispersion.
  • LFP particles were falling onto the surface of the working electrode under their own weight where they were captured by the growing poly-[Ni(CH 3 -SalEn)] polymer.
  • the working electrode was removed from the cell, carefully rinsed with acetonitrile, and dried at 120°C for 1 hour.
  • an electrode was made by cutting a 1 ⁇ 2-inch disk from the sample prepared in Step 2.
  • the provided electrode comprised a substrate and an active layer, wherein said substrate comprised a carbon-coated aluminum foil, and said active layer comprised 80 wt% LFP and 20 wt% poly-[Ni(CH 3 -SalEn)] (based on the weight of the active layer).
  • Such obtained electrode was weighed.
  • a CR-2032 type coin cell was assembled in a stainless steel case (MTI Corporation) using a provided cathode prepared as described above, an anode made of 450 ⁇ thick lithium foil, and a Cellgard 2500 separator. The cell was filled with 50 ⁇ of electrolyte comprising 1 .0 M LiPF 6 solution in a mixed solvent of ethylene carbonate and diethyl carbonate in the volume ratio of 1 : 1 (purchased from ALDRICH). [0101] A comparative cell was fabricated in the same way as described above except for Step 2 of the electrode preparation.
  • Step 2 a slurry was made by combining and carefully mixing 1 g of LFP, 0.125 g of PVDF, 0.125 g of Super P carbon (TIMCAL), and 3 g of NMP. The slurry was evenly deposited using a doctor blade onto one side of the sample prepared in Step l . The thickness of the deposited layer was 550 ⁇ . Such obtained sample was dried at 120°C for 4 hours. After that, it was calendered so that the final density of the active layer was 2.9 g/cm 3 .
  • the comparative cathode was a 1 ⁇ 2-inch disk electrode comprising a carbon-coated aluminum foil substrate coated with an active layer comprising 80 wt% LFP, 10 wt% PVDF, and 10 wt% Super P carbon (based on the weight of the active layer).
  • Such obtained disk was weighed, and its weight was subtracted from the weight of the prepared electrode (for both provided and comparative electrodes) . It can be observed from Fig. 9 that the specific discharge capacity (per gram of the cathode active layer) of the provided cell is about 14.1 % higher than that of the comparative cell.
  • a portion of the discharge curve of the provided cell between about 3.9 V and about 3.4 V corresponds to an electrochemical discharge of the poly-[Ni(CH 3 -SalEn)] polymer (polymer reduction from the oxidized into a neutral state) , which indicates that said polymer stores charge in the provided electrode.
  • the specific capacity of the comparative cell per gram of active material was calculated from the experimental data to be 134 mAh/g.
  • the specific capacity of the provided cell per gram of LFP was calculated to be 148 mAh/g.
  • the above numbers indicate that higher percentage of LFP particles takes part in electrochemical reactions at the provided electrode vs. a comparative electrode despite the fact that the provided electrode does not contain a Super P carbon (a conductive additive) This, in turn, indicates that in the provided electrode, the poly-[Ni(CH 3 -SalEn)] polymer provides efficient electrical connection between particles of LFP and between them and the electrode substrate.
  • the active layer particles do not detach from the electrode substrate during electrode handling despite the fact that the active layer does not contain any conventional binders, such as PVDF.
  • the poly-[Ni(CH 3 -SaEn)] polymer performs a binding function with respect to LFP particles (binds them to each other and to the electrode substrate thus providing mechanical stability to the electrode).
  • the poly-[Ni(CH 3 -SalEn)] polymer performs 3 main functions: it serves as a binder, a conductive additive, and an electroactive charge storing material, which provides higher specific capacity of the power source comprising such electrode as a cathode versus a comparative power source comprising a polymer-free cathode.

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Abstract

L'invention concerne une électrode pour une source d'énergie électrochimique. Dans un mode de réalisation, l'électrode comprend une couche active d'électrode revêtue sur un substrat électroconducteur, la couche active d'électrode comprenant des particules de matériau actif d'électrode liées les unes aux autres et au substrat électroconducteur par un polymère électroconducteur comprenant des unités monomères d'au moins un complexe de métal de transition de base de Schiff N2O2 tétradentate.
PCT/US2018/035280 2017-06-29 2018-05-31 Électrode pour une source d'énergie électrochimique et source d'énergie électrochimique comprenant ladite électrode WO2019005411A1 (fr)

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