Cathode compositions containing piperazine derivatives

Abstract

A cathode composition comprising at least the following components: a) at least one lithium phosphate compound, and b) at least one dispersant selected from the following structure 1 as described herein.

Description

Background Technology

[0001] The rapid development of new energy vehicles (NEVs) has brought tremendous opportunities to the lithium-ion battery (LiB) market. Among the various types of cathode materials used in these batteries, lithium iron phosphate (LFP) has become the most popular cathode material due to its low cost, long cycle stability, and high safety performance. The first step in preparing an LFP cathode is to prepare an LFP cathode slurry. This process is typically carried out by mixing LFP with a binder and a conductive agent in N-methyl-2-pyrrolidone (NMP) as a solvent. Subsequently, the mixture is homogenized until a uniform slurry is obtained.

[0002] Because LFP particles have a high specific surface area, they tend to aggregate, making it difficult to disperse them in a solvent. Furthermore, LFP particles can interact with conductive agents and binders to form aggregates. This aggregation significantly increases the viscosity of the cathode paste. During cathode fabrication, the LFP paste is coated onto an aluminum foil. Subsequently, NMP evaporates, leaving only the active material, binder, and conductive agent on the foil surface. Regarding this process, the high viscosity of the LFP paste leads to two problems: a low coating rate and a delayed evaporation rate, as discussed below.

[0003] Low coating yield. The high viscosity of the slurry will hinder its coating onto the foil, thus reducing the manufacturing efficiency of the cathode. Furthermore, high viscosity will increase the risk of defects on the electrode, which will significantly increase the amount of defective cathodes and reduce manufacturing efficiency.

[0004] Evaporation rate is slowed. To reduce the risk of defects on the electrodes, manufacturers tend to add more NMP solvent to lower the viscosity of the LFP slurry. However, this reduces the solids content of the slurry and increases the time required to remove NMP.

[0005] Therefore, a cathode composition that helps prevent LFP particle aggregation is needed. This reduction in aggregation will, in turn, lower the viscosity of the LFP slurry. Lower viscosity will increase the coating rate of the metal foil, reduce the risk of defects on the cathode, and increase the solids content of the slurry, which will reduce solvent evaporation time. Thus, overall manufacturing efficiency will be improved.

[0006] International publication WO2018 / 156330 discloses a cathode active material layer for lithium batteries. The cathode active material layer comprises various cathode active material particles and optional conductive additives, which are bonded together by a binder comprising a highly elastic polymer (see abstract). The cathode active material may contain organic materials or polymers selected from the following: poly(anthraquinone sulfide) (PAQS); lithium carbon oxide; 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA); poly(anthraquinone sulfide); pyrene-4,5,9,10-tetraone (PYT); polymer-bonded PYT; quinone (triazine); organic materials with redox activity; tetracyanoquinone dimethane (TCNQ); tetracyanoethylene (TCNE); 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP); poly(5-amino-1,4-dihydroxyanthraquinone) (PADAQ); phosphazene disulfide polymer ([(NPS2)3]). n ), lithium-ionized 1,4,5,8-naphthyltetraphenol formaldehyde polymer; hexaaza-trinaphthalene (HATN); hexaazatriphenylhexacarbamate (HAT(CN)6); 5-benzylhydantoin; lithium indigo; lithium pyromellitic acid diimide; tetrahydroxy-p-benzoquinone derivative (THQLi4); N,N'-diphenyl-2,3,5,6-tetraketopiperazine (PHP); N,N'-diallyl-2,3,5,6-tetraketopiperazine (AP) N,N'-dipropyl-2,3,5,6-tetraketopiperazine (PRP); thioether polymers; quinone compounds; 1,4-benzoquinone; 5,7,12,14-pentaphenyltetrazone (PT); 5-amino-2,3-dihydro-1,4-dihydroxyanthraquinone (ADDAQ); 5-amino-1,4-dihydroxyanthraquinone (ADAQ); calixarenequinone; Li4C6O6; Li2C6O6; Li6C6O6; or combinations thereof. See claims 4 and 14.

[0007] U.S. Patent 10,388,990 discloses an electrolyte for lithium secondary batteries, wherein the electrolyte comprises: a lithium salt; a non-aqueous organic solvent; and a piperazine derivative represented by Formula 1 as described herein, having an oxidation potential of about 2 V to about 4 V lower than that of the non-aqueous organic solvent. See abstract. See also U.S. Patent 9,819,054.

[0008] International publication WO2018 / 222348 discloses a method for preparing an alkali metal battery, the method comprising: (a) combining a certain amount of active material, a certain amount of electrolyte, and conductive additives to form a deformable and conductive electrode material; (b) forming the electrode material into a quasi-solid polymer electrode; (c) forming a second electrode; and (d) forming an alkali metal battery by combining the quasi-solid electrode and the second electrode. See abstract. The cathode active material may contain organic materials or polymers selected from the following: poly(anthraquinone sulfide) (PAQS); lithium carbon oxide; 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA); poly(anthraquinone sulfide); pyrene-4,5,9,10-tetraone (PYT); polymer-bonded PYT; quinone (triazine); organic materials with redox activity; tetracyanoquinone dimethane (TCNQ); tetracyanoethylene (TCNE); 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP); poly(5-amino-1,4-dihydroxyanthraquinone) (PADAQ); phosphazene disulfide polymer ([(NPS2)3]). n ), lithium-ionized 1,4,5,8-naphthyltetraphenol formaldehyde polymer; hexaazatrinaphthalene (HATN); hexaazatriphenylhexacarbamate (HAT(CN)6); 5-benzylhydantoin; lithium indigo; lithium pyromellitic acid diimide; tetrahydroxy-p-benzoquinone derivative (THQLi4); N,N'-diphenyl-2,3,5,6-tetraketopiperazine (PHP); N,N'-diallyl-2,3,5,6-tetraketopiperazine (AP) N,N'-dipropyl-2,3,5,6-tetraketopiperazine (PRP); thioether polymers; quinone compounds; 1,4-benzoquinone; 5,7,12,14-pentaphenyltetrazone (PT); 5-amino-2,3-dihydro-1,4-dihydroxyanthraquinone (ADDAQ); 5-amino-1,4-dihydroxyanthraquinone (ADAQ); calixarenequinone; Li4C6O6; Li2C6O6; Li6C6O6; or combinations thereof. See claims 28 and 35.

[0009] International publication WO2019 / 009242 discloses a binder cathode composition having reduced viscosity while maintaining its bonding properties during electrode production. The binder cathode composition can be used to bond electrode active materials to a current collector and is characterized by containing a binder resin and a dispersant, wherein the dispersant is a compound represented by formula (I) or formula (II) as described herein. See English abstract.

[0010] U.S. Publication No. 2011 / 0206979 discloses a lithium-ion rechargeable battery or secondary battery, comprising: a negative electrode with graphite carbon as the active material; a positive electrode with LiFePO4 as the active material; and an ionic liquid electrolyte containing at least one of the following formula: C +A - An ionic liquid and at least one conductive salt, wherein C + Represents a cation, and A - This indicates anion; Ionic liquid electrolytes also contain organic additives, namely vinyl ethylene carbonate (VEC). See abstract. The cation C of ionic liquids... + It may be selected from hydrated hydrogen, oxonium, ammonium, amidonium, phosphonium, ureonium, thioureaonium, guanidineonium, sulfonium, phospholium, iodonium, carbonium cations; heterocyclic cations such as pyridinium, quinolineonium, isoquinolineonium, imidazolineonium, pyrazolium, imidazolineonium, triazolium, pyridazineonium, pyrimidineonium, pyrrolidineonium, thiazolineonium, oxazolium, pyrazineonium, piperazineonium, piperidinium, pyrrololineonium, pyrazineonium, indoleonium, quinoxalineonium, thiomorpholineonium, morpholineonium, and indoleonium cations; and the tautomer forms of these heterocyclic cations (see paragraph

[0078] ).

[0011] CN102491304B (machine translation) discloses a method for preparing lithium iron phosphate, which is used as a cathode material for lithium-ion batteries in an ionic eutectic mixture. In this method, an ionic eutectic mixture is obtained by mixing a urea / carboxylic acid / alcohol with a quaternary ammonium salt and an organic amine or organic base as a modifier. This mixture is used as a reaction solvent and a template agent, and pure-phase lithium iron phosphate with high crystallinity is directly obtained by ionothermal synthesis. See abstract. The organic amine can be ethanolamine, triethanolamine, hexahydroaniline, or hexamethylenediamine. The organic base can be anhydrous piperazine (see claim 3).

[0012] CN103943825A (machine translation) discloses a method for replenishing lithium in a new lithium-ion battery. A liquid solution method is used to replenish lithium to the electrode. The method includes the following steps: a) preparing a solvent capable of dissolving metallic lithium, and dissolving the metallic lithium to form a lithium solution; b) bringing an electrode sheet into full contact with the lithium solution, allowing the lithium solution to permeate into the electrode; c) removing the solvent from the electrode sheet to obtain a lithium-replenished electrode sheet. See abstract. The solvent may contain polyamine compounds such as ethylenediamine, N,N'-dimethylethylenediamine, piperazine, diaminopropane, diaminobutane, dimethyldiaminobutane, triamidoethylamine, tertiary benzylamine, tertiary sulfonylamine, N-benzyl,N-methyldecanoic acid amine (see claim 3).

[0013] CN115579460A (machine translation) discloses an aqueous positive electrode slurry for lithium iron phosphate batteries, its preparation method, lithium iron phosphate batteries, and positive electrode sheets. The preparation method includes the following steps: (1) mixing lithium iron phosphate powder with a conductive agent and a first-part thickener by dry mixing to obtain a mixed material; (2) adding water and a surfactant to the mixture obtained in step (1) to obtain a first mixed slurry with a solid content of 80% to 90% by weight; (3) dispersing water into the first mixed slurry obtained in step (2) to obtain a second mixed slurry with a solid content of 75% to 80% by weight; (4) dispersing a second-part thickener and water into the second mixed slurry obtained in step (3); and (5) dispersing an aqueous binder and water into a third mixed slurry. According to this preparation method, by adding surfactants and thickeners and employing a multi-step high-viscosity, high-temperature stirring preparation method, an aqueous positive electrode slurry for lithium iron phosphate batteries is prepared, resulting in a uniformly dispersed and well-stable aqueous positive electrode slurry for lithium iron phosphate batteries. See abstract. The surfactant is selected from at least one of 2-amino-2-methyl-1-propanol, styrene-acrylate copolymer and polyvinylpyrrolidone (see claim 2).

[0014] The battery, electrode, and / or composition are also disclosed in U.S. Patent 10,741,832; U.S. Publication 2019 / 0296360; CN102130338A (machine translation) and CN106663802B (machine translation).

[0015] However, as discussed above, there remains a need for cathode compositions that help prevent LFP particle aggregation. This need is met as discussed below. Summary of the Invention

[0016] A cathode composition comprising at least the following components a) and b):

[0017] a) at least one lithium phosphate compound,

[0018] b) At least one dispersant selected from structure 1 below:

[0019] R1 and R2 are each independently C1-C6 alkylene groups. Attached Figure Description

[0020] Figure 1 This is a bar graph showing the viscosity of the cathode composition. Detailed Implementation

[0021] Compositions that reduce LFP particle aggregation have been discovered, thereby achieving a reduction in composition viscosity. These compositions also exhibit negligible corrosion and can be prepared in water, resulting in a more environmentally friendly impact.

[0022] As discussed above, a cathode composition is provided comprising at least the following components a) and b):

[0023] a) at least one lithium phosphate compound,

[0024] b) At least one dispersant selected from structure 1 below:

[0025] R1 and R2 are each independently C1-C6 alkylene groups.

[0026] The cathode composition described above may comprise a combination of two or more embodiments as described herein. Each component may independently comprise a combination of two or more embodiments as described herein. Structure 1 may comprise a combination of two or more embodiments as described herein. As used herein, with respect to structure 1, R1=R1 and R2=R2. The alkylene groups may be straight-chain, branched, cyclic, or any combination thereof.

[0027] In one embodiment or a combination of two or more embodiments described herein, the cathode composition is a slurry.

[0028] In one embodiment or a combination of two or more embodiments each described herein, for component b, structure 1, R1 = R2.

[0029] In one embodiment or a combination of two or more embodiments each described herein, component b is selected from structure 1b) as shown above:

[0030] , where n is an integer from 1 to 6, or 1 to 5, or 1 to 4, or 2 to 4, or 2 to 3, or 2; and m is an integer from 1 to 6, or 1 to 5, or 1 to 4, or 2 to 4, or 2 to 3, or 2.

[0031] In one embodiment or a combination of two or more embodiments described herein, component b is selected from structure 1b) as shown above, and either n=m, or n=m=2 or 3, or n=m=2.

[0032] In one embodiment or a combination of two or more embodiments described herein, component a is selected from lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, or combinations thereof. In one embodiment or a combination of two or more embodiments described herein, component a is lithium iron phosphate.

[0033] In one embodiment or a combination of two or more embodiments each described herein, component a is in particulate form. In one embodiment or a combination of two or more embodiments each described herein, the cathode composition further comprises a carbon coating on the particles of component a to form carbon-coated particles.

[0034] In one embodiment or a combination of two or more embodiments described herein, component b is present in an amount of ≥0.05 wt%, or ≥0.06 wt%, or ≥0.08 wt%, or ≥0.10 wt%, or ≥0.12 wt%, or ≥0.14 wt%, or ≥0.16 wt%, or ≥0.18 wt%, or ≥0.20 wt%, based on the weight of the cathode composition. In one embodiment or a combination of two or more embodiments described herein, component b is present in an amount of ≤1.00 wt%, or ≤0.90 wt%, or ≤0.80 wt%, or ≤0.70 wt%, or ≤0.60 wt%, or ≤0.50 wt%, or ≤0.40 wt%, or ≤0.30 wt%, based on the weight of the cathode composition.

[0035] In one embodiment or a combination of two or more embodiments described herein, the weight ratio of component a to component b is ≥150, or ≥200, or ≥250, or ≥300, or ≥350, or ≥400, or ≥450. In one embodiment or a combination of two or more embodiments described herein, the weight ratio of component a to component b is ≤700, or ≤650, or ≤600, or ≤550, or ≤500.

[0036] In one embodiment or a combination of two or more embodiments described herein, component a is present in an amount of ≥35% by weight, or ≥40% by weight, or ≥45% by weight, or ≥50% by weight, or ≥52% by weight, or ≥54% by weight, or ≥55% by weight, or ≥56% by weight, or ≥58% by weight, or ≥60% by weight, based on the weight of the cathode composition. In one embodiment or a combination of two or more embodiments described herein, component a is present in an amount of ≤80% by weight, or ≤75% by weight, or ≤70% by weight, or ≤68% by weight, or ≤66% by weight, or ≤65% by weight, or ≤64% by weight, or ≤62% by weight, based on the weight of the cathode composition.

[0037] In one embodiment or a combination of two or more embodiments described herein, the cathode composition further comprises a solvent as component c. In one embodiment or a combination of two or more embodiments described herein, the solvent (component c) is N-methyl-2-pyrrolidone (NMP).

[0038] In one embodiment or a combination of two or more embodiments described herein, component c is present in an amount of ≥20.0 wt%, or ≥22.0 wt%, or ≥25.0 wt%, or ≥28.0 wt%, or ≥30.0 ​​wt%, or ≥32.0 wt%, or ≥34.0 wt%, or ≥66.0 wt%, based on the weight of the cathode composition. In one embodiment or a combination of two or more embodiments described herein, component c is present in an amount of ≤60.0 wt%, or ≤58.0 wt%, or ≤56.0 wt%, or ≤54.0 wt%, or ≤52.0 wt%, or ≤50.0 wt%, or ≤48.0 wt%, or ≤46.0 wt%, or ≤44.0 wt%, or ≤42.0 wt%, or ≤40.0 wt%, or ≤38.0 wt%, based on the weight of the cathode composition.

[0039] In one embodiment or a combination of two or more embodiments described herein, the weight ratio of component a to component c is ≥1.30, or ≥1.35, or ≥1.40, or ≥1.45, or ≥1.50, or ≥1.52, or ≥1.54, or ≥1.56, or ≥1.58, or ≥1.60. In one embodiment or a combination of two or more embodiments described herein, the weight ratio of component a to component c is ≤2.00, or ≤1.95, or ≤1.90, or ≤1.85, or ≤1.80, or ≤1.78, or ≤1.76, or ≤1.74, or ≤1.72, or ≤1.70, or ≤1.65.

[0040] In one embodiment or a combination of two or more embodiments described herein, the cathode composition further comprises at least one conductive agent as component d.

[0041] In one embodiment or a combination of two or more embodiments described herein, the cathode composition further comprises at least one binder as component e.

[0042] In one embodiment or a combination of two or more embodiments each described herein, based on the weight of the cathode composition, the sum of components a and b is ≥40.0% by weight, or ≥45.0% by weight, or ≥50.0% by weight, or ≥52.0% by weight, or ≥54.0% by weight, or ≥56.0% by weight, or ≥58.0% by weight, or ≥60.0% by weight. And / or The amount present is ≤80.0% by weight, or ≤78.0% by weight, or ≤76.0% by weight, or ≤74.0% by weight, or ≤72.0% by weight, or ≤70.0% by weight.

[0043] In one embodiment or a combination of two or more embodiments each described herein, the sum of components a, b, and c, based on the weight of the cathode composition, is ≥80.0% by weight, or ≥82.0% by weight, or ≥84.0% by weight, or ≥86.0% by weight, or ≥88.0% by weight, or ≥90.0% by weight, or ≥92.0% by weight, or ≥94.0% by weight, or ≥96.0% by weight. And / or The amount present is ≤100.0% by weight, or ≤99.5% by weight, or ≤99.0% by weight, or ≤98.5% by weight, or ≤98.0% by weight.

[0044] In one embodiment or a combination of two or more embodiments each described herein, the sum of components a, b, c, and d, based on the weight of the cathode composition, is ≥85.00% by weight, or ≥88.00% by weight, or ≥90.00% by weight, or ≥92.00% by weight, or ≥94.00% by weight, or ≥96.00% by weight, or ≥97.00% by weight, or ≥98.00% by weight. And / or The amount present is ≤100.00% by weight, or ≤99.50% by weight, or ≤99.00% by weight, or ≤98.50% by weight.

[0045] A cathode is also provided, comprising an active layer formed of a cathode composition of any one embodiment or a combination of two or more embodiments described herein. In one embodiment or a combination of two or more embodiments described herein, the cathode further comprises a metal foil (or a metal foil current collector). In one embodiment or a combination of two or more embodiments described herein, the metal of the metal foil is selected from aluminum, aluminum alloys, copper, copper alloys, further selected from aluminum or copper, and further selected from aluminum.

[0046] A cathode assembly is also provided, comprising at least one cathode of any one embodiment or a combination of two or more embodiments described herein.

[0047] A battery is also provided, which includes a cathode assembly of any one embodiment or a combination of two or more embodiments described herein.

[0048] In one embodiment or a combination of two or more embodiments described herein, the battery is a lithium battery.

[0049] A method for forming a cathode composition according to any embodiment or a combination of two or more embodiments described herein is also provided, the method comprising mixing at least components a and b. In one embodiment or a combination of two or more embodiments described herein, the method further comprises mixing at least components a, b, and c. In one embodiment or a combination of two or more embodiments described herein, the method further comprises mixing at least components a, b, c, and d. In one embodiment or a combination of two or more embodiments described herein, the method further comprises mixing at least components a, b, c, d, and e.

[0050] A method for forming a cathode is also provided, the method comprising applying a cathode composition of any one embodiment or a combination of two or more embodiments described herein to a flat surface of a metal foil. In one embodiment or a combination of two or more embodiments described herein, the metal of the metal foil is selected from aluminum, aluminum alloys, copper, copper alloys, further selected from aluminum or copper, and further selected from aluminum.

[0051] A method for forming a cathode assembly is also provided, the method comprising compacting at least one cathode of any embodiment or a combination of two or more embodiments described herein. In one embodiment or a combination of two or more embodiments described herein, the method further comprises compacting at least two cathodes.

[0052] A method for forming a battery is also provided, which includes inserting a cathode assembly of any one embodiment or a combination of two or more embodiments described herein into an electrolyte.

[0053] Component b – N,N'-substituted piperazine

[0054] Component b is described herein. The synthesis of N,N'-substituted piperazines is known in the art, and various ether amines are commercially available. For example, N,N'-substituted piperazines can be produced by reacting an oxide with a piperazine. Further, as an example, 1,4-bis(2-hydroxyethyl)piperazine can be synthesized by reacting EO (ethylene oxide) with a piperazine at a target ratio of 2:1. N,N'-substituted piperazines can be recovered using conventional techniques.

[0055] Component b can be in the form of a liquid cathode composition added to an aqueous solution of the cathode composition. The N,N'-substituted piperazine itself can be in liquid form at room temperature (22°C), therefore the "stock" cathode composition can be a cathode composition in which the N,N'-substituted piperazine is in pure form (100% by weight). The stock cathode composition can also be prepared with the N,N'-substituted piperazine in one or more compatible solvents, such as, for example, in which the N,N'-substituted piperazine is present in an amount ranging from about 30% (by weight) to about 99% (by weight). The solvent can be water. The N,N'-substituted piperazine can be in the form of a solid composition, such as in the form of powder or granules added to an aqueous solution of the cathode composition.

[0056] definition

[0057] Unless stated to the contrary, implied by the context, or as is customary in the art, all parts and percentages are based on weight, and all test methods are current methods as of the date of this disclosure.

[0058] As used herein, the term "composition" includes a mixture of materials comprising the composition as well as reaction and decomposition products formed from the composition materials. Any reaction or decomposition products are typically present in trace or residual amounts.

[0059] As used herein, the term "cathode composition" includes a mixture of materials comprising a cathode composition and reaction and decomposition products formed from the cathode composition materials. Any reaction or decomposition products are typically present in trace or residual amounts.

[0060] As used herein, the term "polymer" refers to a polymer compound prepared by polymerizing monomers of the same or different types. Therefore, the general term polymer includes the terms homopolymer (used to refer to polymers prepared from only one type of monomer; it should be understood that trace impurities may be incorporated into the polymer structure) and interpolymer as defined below. Trace impurities (such as catalyst residues) may be incorporated into and / or within the polymer. Typically, polymers are stabilized with one or more stabilizers in very low amounts ("ppm").

[0061] As used herein, the term "interpolymer" refers to a polymer obtained by polymerizing at least two different types of monomers. The term interpolymer therefore includes the term copolymer (used to refer to polymers prepared from two different types of monomers) and polymers prepared from more than two different types of monomers.

[0062] As used herein, the term "lithium phosphate compound" refers to a compound containing at least one lithium cation (Li). +1 ) and at least one phosphate anion (PO4) -3Compounds containing at least one other cation, such as a metal cation.

[0063] As used herein, the term "slurry" refers to a mixture comprising one or more insoluble materials (such as particles) suspended in a solvent (such as water). The mixture may also contain one or more soluble materials, such as glucose dissolved in a solvent (such as water).

[0064] As used herein, the term "solvent" refers to a liquid substance of one or more compounds that can dissolve and / or disperse one or more other substances.

[0065] As used herein, the term "carbon-coated particles" refers to particles coated with a carbon layer. Typically, 50% or more of the surface area of ​​the particles is coated with carbon. Preferably, 90% or more of the surface area of ​​the particles is coated with carbon.

[0066] As used in this article, the term "cathode" in relation to batteries refers to the electrode in a polarized electrical device through which current flows out.

[0067] As used in this article, the term "anode" in relation to batteries refers to the electrode in a polarizing electrical device through which current flows from the external circuit.

[0068] The term "active layer" in electrode terminology refers to the layer attached to the current collector, which is thus able to transport electrons.

[0069] As used herein, the term “conductive agent” in relation to a cathode composition refers to a material (e.g., a carbon material) added to the composition to increase the ability of the active layer to charge and discharge electrons.

[0070] As used herein, the term "binder" in relation to a cathode composition refers to a material (e.g., a polymer) added to the composition to provide adhesion of the components within the active layer and between the active layer and the metal foil.

[0071] As used herein, the term "dispersant" in relation to cathode compositions refers to a substance that is typically added to a suspension of solid or liquid particles in a liquid (such as a slurry or emulsion) to improve particle separation and prevent their settling or agglomeration.

[0072] As used herein, the term "dispersant for conductive agent" in relation to cathode compositions refers to a substance used to improve the separation of the conductive agent within the composition and to prevent the conductive agent from settling or agglomerating.

[0073] As used herein, the phrase "coating a cathode composition onto a flat surface of a metal foil" and similar phrases refer to the action of bringing the cathode composition into contact with a metal surface. This contact can be achieved by wetting the metal surface with the cathode composition using a brush, sprayer, roller, or any other means known in the art.

[0074] Regarding metal foils having a specific width, length, and thickness, or having a specific diameter and thickness, or other dimensions, the term "flat surface" refers to a surface area formed by a foil of that width and length, or by a foil of that diameter, or by a foil of a larger size.

[0075] As used herein, the term "cathode assembly" refers to a battery component that includes one or more cathodes.

[0076] As used in this article, the term "electrolyte" in relation to batteries refers to a solution that can transport ions back and forth between the cathode and anode of a battery.

[0077] As used herein, the term "electrochemical cell" refers to a device that generates electrical energy from chemical energy. Electrical energy can also be applied to these cells to initiate one or more chemical reactions.

[0078] As used in this article, the term "battery" refers to a container containing one or more electrochemical cells in which chemical energy is converted into electrical energy.

[0079] As used herein, the term "lithium battery" refers to a battery that uses a lithium source in one or more electrochemical cells. Examples of lithium batteries include, but are not limited to, lithium-ion batteries, lithium metal batteries, lithium-sulfur batteries, lithium-selenium batteries, or lithium-air batteries.

[0080] As used herein, the term "water" refers to H2O. This type of water (H2O) is essentially pure water and therefore may or may not contain one or more impurities, such as, for example, dissolved inorganic ions. Typically, based on the weight of the water sample, impurities are present in amounts of ≤1000 ppm, preferably ≤100 ppm, more preferably ≤10 ppm, and even more preferably ≤1 ppm.

[0081] As used herein, the terms “thermally treating,” “thermally treated,” “thermal treatment,” and similar terms with respect to the respective cathode compositions or compounds or coated foils discussed herein refer to raising the temperature of “material at tissue site” by applying heat. As an example, heat may be applied, for instance, by an electrical device (e.g., a heating coil in an oven). Note that the temperature at which heat treatment is performed refers to the temperature of the device “applying heat,” or, if the device contains a closed or semi-closed atmosphere, the temperature of the atmosphere within the device, such as the atmosphere in an oven or tunnel (e.g., the air temperature in a hot air oven or hot air tunnel).

[0082] The terms “comprising,” “including,” “having,” and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all compositions claimed using the term “comprising” may include any additional additives, adjuvants, or compounds, whether in polymeric or other forms. In contrast, the term “substantially constitutes” excludes any other components, steps, or procedures from any subsequently listed scope, except those not essential for operability. The term “consisting of” excludes any components, steps, or procedures not specifically described or listed.

[0083] List of some cathode compositions and method characteristics

[0084] A] A cathode composition comprising at least the following components a) and b):

[0085] a) at least one lithium phosphate compound,

[0086] b) At least one dispersant selected from structure 1 below:

[0087] R1 and R2 are each independently C1-C6 alkylene groups.

[0088] B] The cathode composition according to A] above, wherein the cathode composition is a slurry.

[0089] C] According to the cathode composition described in A] or B] above, wherein for component b, structure 1, R1=R2.

[0090] D] The cathode composition according to any one of A]-C] (A] to C] above, wherein for component b, structure 1, R1 is C1-C5 alkylene, or C1-C4 alkylene, or C1-C3 alkylene, or C1-C2 alkylene, or C2 alkylene.

[0091] E] The cathode composition according to any one of A]-D] above, wherein for component b, structure 1, R2 is C1-C5 alkylene, or C1-C4 alkylene, or C1-C3 alkylene, or C1-C2 alkylene, or C2 alkylene.

[0092] F] The cathode composition according to any one of A]-E] above, wherein component b is selected from structure 1b) as shown below:

[0093] Where n is an integer from 1 to 6, or 1 to 5, or 1 to 4, or 2 to 4, or 2 to 3, or 2; and m is an integer from 1 to 6, or 1 to 5, or 1 to 4, or 2 to 4, or 2 to 3, or 2.

[0094] G] According to the cathode composition described in F] above, wherein component b is selected from structure 1b) as shown above, and either n=m, or n=m=2 or 3, or n=m=2.

[0095] H] The cathode composition according to any one of A]-G] above, wherein component a is selected from lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate or a combination thereof.

[0096] I] According to the cathode composition described in H] above, wherein component a is lithium iron phosphate.

[0097] J] The cathode composition according to any one of A]-I] above, wherein component a is in particulate form.

[0098] K] According to the cathode composition described in J] above, wherein the cathode composition further comprises a carbon coating located on the particles of component a to form carbon-coated particles.

[0099] L] According to the cathode composition described in K] above, wherein, based on the weight of the carbon-coated particles, the carbon-coated particles comprise ≥80% by weight, or ≥85% by weight, or ≥90% by weight, or ≥92% by weight, or ≥94% by weight, or ≥96% by weight, or ≥97% by weight, or ≥98% by weight. And / or ≤100% by weight, or ≤99% by weight of lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, or combinations thereof.

[0100] M] According to the cathode composition described in K] or L] above, wherein, based on the weight of the carbon-coated particles, the carbon-coated particles comprise ≥80% by weight, or ≥85% by weight, or ≥90% by weight, or ≥92% by weight, or ≥94% by weight, or ≥96% by weight, or ≥98% by weight. And / or Lithium iron phosphate ≤100% by weight or ≤99% by weight.

[0101] [N] The cathode composition according to any one of [K]-M] above, wherein, based on the weight of the cathode composition, the carbon-coated particles are ≥40% by weight, or ≥45% by weight, or ≥50% by weight, or ≥55% by weight. And / or The amount present is ≤90% by weight, or ≤85% by weight, or ≤80% by weight, or ≤75% by weight, or ≤70% by weight, or ≤65% by weight.

[0102] O] The cathode composition according to any one of K]-N] above, wherein the weight ratio of the carbon-coated particles to component b is ≥100, or ≥150, or ≥200, or ≥250, or ≥300, or ≥350, or ≥400, or ≥450, or ≥500 And / or ≤700, or ≤650, or ≤600, or ≤550.

[0103] P] The cathode composition according to any one of A]-O] above, wherein, based on the weight of the cathode composition, component b is present in an amount of ≥0.05 wt%, or ≥0.06 wt%, or ≥0.08 wt%, or ≥0.10 wt%, or ≥0.12 wt%, or ≥0.14 wt%, or ≥0.16 wt%, or ≥0.18 wt%, or ≥0.20 wt%.

[0104] Q] The cathode composition according to any one of A]-P] above, wherein, based on the weight of the cathode composition, the component b is present in an amount of ≤1.00 wt%, or ≤0.90 wt%, or ≤0.80 wt%, or ≤0.70 wt%, or ≤0.60 wt%, or ≤0.50 wt%, or ≤0.40 wt%, or ≤0.30 wt%.

[0105] R] The cathode composition according to any one of A]-Q] above, wherein the weight ratio of component a to component b is ≥150, or ≥200, or ≥250, or ≥300, or ≥350, or ≥400, or ≥450, or ≥500.

[0106] S] The cathode composition according to any one of A]-R] above, wherein the weight ratio of component a to component b is ≤700, or ≤650, or ≤600, or ≤550.

[0107] T] The cathode composition according to any one of A]-S] above, wherein, based on the weight of the cathode composition, component a is present in an amount of ≥35% by weight, or ≥40% by weight, or ≥45% by weight, or ≥50% by weight, or ≥52% by weight, or ≥54% by weight, or ≥55% by weight, or ≥56% by weight, or ≥58% by weight, or ≥60% by weight.

[0108] U] The cathode composition according to any one of A]-T] above, wherein, based on the weight of the cathode composition, component a is present in an amount of ≤80% by weight, or ≤75% by weight, or ≤70% by weight, or ≤68% by weight, or ≤66% by weight, or ≤65% by weight, or ≤64% by weight, or ≤62% by weight.

[0109] V] The cathode composition according to any one of A]-U] above, wherein the cathode composition comprises only one lithium phosphate compound as component a.

[0110] W] The cathode composition according to any one of A]-V] above, wherein the cathode composition comprises, as component b, only one dispersant selected from structure 1.

[0111] X] The cathode composition according to any one of A]-W] above, wherein the cathode composition further comprises a solvent as component c.

[0112] Y] According to the cathode composition described in X] above, wherein the solvent (component c) is N-methyl-2-pyrrolidone (NMP).

[0113] Z] According to the cathode composition described in X] or Y] above, wherein, based on the weight of the cathode composition, the component c is present in an amount of ≥20.0% by weight, or ≥22.0% by weight, or ≥25.0% by weight, or ≥28.0% by weight, or ≥30.0% by weight, or ≥32.0% by weight, or ≥34.0% by weight, or ≥36.0% by weight.

[0114] A2] The cathode composition according to any one of X]-S] above, wherein, based on the weight of the cathode composition, the component c is present in an amount of ≤60.0% by weight, or ≤58.0% by weight, or ≤56.0% by weight, or ≤54.0% by weight, or ≤52.0% by weight, or ≤50.0% by weight, or ≤48.0% by weight, or ≤46.0% by weight, or ≤44.0% by weight, or ≤42.0% by weight, or ≤40.0% by weight, or ≤38.0% by weight.

[0115] B2] The cathode composition according to any one of X]-A2] above, wherein the weight ratio of component a to component c is ≥1.30, or ≥1.35, or ≥1.40, or ≥1.45, or ≥1.50, or ≥1.52, or ≥1.54, or ≥1.56, or ≥1.58, or ≥1.60.

[0116] C2] The cathode composition according to any one of X]-B2] above, wherein the weight ratio of component a to component c is ≤2.00, or ≤1.95, or ≤1.90, or ≤1.85, or ≤1.80, or ≤1.78, or ≤1.76, or ≤1.74, or ≤1.72, or ≤1.70, or ≤1.68, or ≤1.66, or ≤1.64, or ≤1.62.

[0117] D2] The cathode composition according to any one of A]-C2], wherein the cathode composition further comprises at least one conductive agent as component d.

[0118] E2] The cathode composition according to D2] wherein component d is carbon black, and further is conductive carbon black.

[0119] F2] According to the cathode composition described in D2] or E2] above, wherein, based on the weight of the cathode composition, component d is in the form of ≥0.20% by weight, or ≥0.25% by weight, or ≥0.30% by weight, or ≥0.35% by weight, or ≥0.40% by weight, or ≥0.45% by weight, or ≥0.50% by weight, or ≥0.55% by weight, or ≥0.60% by weight. And / or The amount present is ≤1.00% by weight, or ≤0.95% by weight, or ≤0.90% by weight, or ≤0.85% by weight, or ≤0.80% by weight, or ≤0.75% by weight, or ≤0.70% by weight, or ≤0.65% by weight.

[0120] G2] The cathode composition according to any one of D2]-F2] above, wherein the cathode composition comprises only one conductive agent as component d.

[0121] H2] The cathode composition according to any one of A]-G2], wherein the cathode composition further comprises at least one binder as component e.

[0122] I2] The cathode composition according to H2], wherein component e is polyvinylidene fluoride.

[0123] J2] According to the cathode composition described above in H2] or I2], wherein, based on the weight of the cathode composition, component e is in the form of ≥0.50% by weight, or ≥0.70% by weight, or ≥1.00% by weight, or ≥1.20% by weight, or ≥1.40% by weight, or ≥1.60% by weight, or ≥1.70% by weight, or ≥1.80% by weight. And / or The amount present is ≤5.00% by weight, or ≤4.50% by weight, or ≤4.00% by weight, or ≤3.50% by weight, or ≤3.00% by weight, or ≤2.50% by weight, or ≤2.00% by weight.

[0124] K2] The cathode composition according to any one of H2]-J2] above, wherein the cathode composition contains only one binder as component e.

[0125] L2] The cathode composition according to any one of A]-K2], wherein the cathode composition further comprises, as component f, a "dispersant for the conductive agent".

[0126] M2] The cathode composition according to L2], wherein component f is polyvinylpyrrolidone, and further is PVP K30.

[0127] [N2] According to the cathode composition described in [L2] or [M2] above, wherein, based on the weight of the cathode composition, component f is in the form of ≥0.020% by weight, or ≥0.025% by weight, or ≥0.030% by weight, or ≥0.035% by weight, or ≥0.040% by weight, or ≥0.045% by weight, or ≥0.050% by weight, or ≥0.055% by weight, or ≥0.060% by weight. And / or The amount present is ≤0.100% by weight, or ≤0.095% by weight, or ≤0.090% by weight, or ≤0.085% by weight, or ≤0.080% by weight, or ≤0.075% by weight, or ≤0.070% by weight, or ≤0.065% by weight.

[0128] O2] The cathode composition according to any one of L2]-N2] above, wherein the cathode composition comprises only one "dispersant for the conductive agent" as component f.

[0129] [P2] The cathode composition according to any one of [L2]-[O2] above, wherein the weight ratio of component d to component f is ≥7.0, or ≥7.5, or ≥8.0, or ≥8.5, or ≥, or ≥9.0, or ≥9.5, or ≥10. And / or ≤20, or ≤18, or ≤16, or ≤14, or ≤12, or ≤11.

[0130] Q2] The cathode composition according to any one of A]-P2] above, wherein, based on the weight of the cathode composition, the sum of components a and b is ≥40.0% by weight, or ≥45.0% by weight, or ≥50.0% by weight, or ≥52.0% by weight, or ≥54.0% by weight, or ≥56.0% by weight, or ≥58.0% by weight, or ≥60.0% by weight. And / or The amount present is ≤80.0% by weight, or ≤78.0% by weight, or ≤76.0% by weight, or ≤74.0% by weight, or ≤72.0% by weight, or ≤70.0% by weight, or ≤68.0% by weight, or ≤66.0% by weight.

[0131] R2] The cathode composition according to any one of X]-Q2] above, wherein, based on the weight of the cathode composition, the sum of components a, b and c is ≥80.0% by weight, or ≥82.0% by weight, or ≥84.0% by weight, or ≥86.0% by weight, or ≥88.0% by weight, or ≥90.0% by weight, or ≥92.0% by weight, or ≥94.0% by weight, or ≥96.0% by weight, or ≥97.0% by weight. And / or The amount present is ≤100.0% by weight, or ≤99.5% by weight, or ≤99.0% by weight, or ≤98.5% by weight, or ≤98.0% by weight.

[0132] S2] The cathode composition according to any one of D2]-R2] above, wherein, based on the weight of the cathode composition, the sum of components a, b, c and d is ≥85.00% by weight, or ≥88.00% by weight, or ≥90.00% by weight, or ≥92.00% by weight, or ≥94.00% by weight, or ≥96.00% by weight, or ≥97.00% by weight, or ≥98.00% by weight. And / or The amount present is ≤100.00% by weight, or ≤99.50% by weight, or ≤99.00% by weight, or ≤98.50% by weight.

[0133] [T2] ​​The cathode composition according to any one of [H2]-S2] above, wherein, based on the weight of the cathode composition, the sum of components a, b, c, d and e is ≥90.00% by weight, or ≥91.00% by weight, or ≥92.00% by weight, or ≥93.00% by weight, or ≥94.00% by weight, or ≥95.00% by weight, or ≥96.00% by weight, or ≥97.00% by weight, or ≥97.50% by weight, or ≥98.00% by weight, or ≥98.50% by weight, or ≥99.00% by weight. And / or It exists in amounts of ≤100.00% by weight or ≤99.98% by weight.

[0134] U2] The cathode composition according to any one of A]-T2] above, wherein, based on the weight of the cathode composition, the cathode composition contains ≤1.0ppm, or ≤0.50ppm, or ≤0.20ppm, or ≤0.10ppm, or ≤0.05ppm, or ≤0.02ppm, or ≤0.01ppm of amino alcohol, and further wherein the cathode composition is free of amino alcohol.

[0135] V2] The cathode composition according to any one of A]-U2] above, wherein, based on the weight of the cathode composition, the cathode composition contains ≤1.0 ppm, or ≤0.50 ppm, or ≤0.20 ppm, or ≤0.10 ppm, or ≤0.05 ppm, or ≤0.02 ppm, or ≤0.01 ppm of "2-amino-2-methyl-1-propanol", and further wherein the cathode composition does not contain "2-amino-2-methyl-1-propanol".

[0136] A3] A cathode comprising an active layer formed from any one of the cathode compositions described in A]-V2] above.

[0137] B3] The cathode according to A3], wherein the cathode further includes a metal foil.

[0138] C3] According to the cathode described in B3] above, the metal of the metal foil is selected from aluminum, aluminum alloy, copper, copper alloy, further selected from aluminum or copper, and further selected from aluminum.

[0139] D3] The cathode according to B3] or C3] above, wherein the metal has a diameter of ≥10µm, or ≥12µm, or ≥14µm. And / or Thickness ≤25µm, or ≤22µm, or ≤20µm, or ≤18µm, or ≤16µm.

[0140] E3] The cathode according to any one of B3]-D3] above, wherein the cathode composition is coated onto a flat surface of the metal foil to form a coated foil.

[0141] F3] According to the cathode described in E3 above, the coated foil is heat-treated and further heat-treated to evaporate the solvent, thereby forming the active layer on the metal foil.

[0142] G3] According to the cathode described in F3 above, wherein the coated foil is at ≥50°C, or ≥55°C, or ≥60°C, or ≥65°C, or ≥70°C, or ≥75°C, or ≥80°C And / orHeat treatment shall be performed at temperatures of ≤120℃, ≤115℃, ≤110℃, ≤105℃, ≤100℃, ≤95℃, ≤90℃, or ≤85℃.

[0143] H3] The cathode according to any one of A3]-G3] above, wherein the cathode is compressed under pressure.

[0144] [I3] According to the cathode described in [H3] above, wherein the pressure is ≥5.0MT (mTorr), or ≥10MT, or ≥15MT, or ≥20MT, or ≥22MT, or ≥24MT, or ≥26MT And / or ≤40MT, or ≤38MT, or ≤36MT, or ≤34MT, or ≤32MT, or ≤30MT, or ≤28MT.

[0145] J3] A cathode assembly comprising at least one cathode as described in any one of A3]-I3] above.

[0146] K3] The cathode assembly according to J3] above, wherein the cathode assembly includes at least two cathodes.

[0147] L3] A battery comprising the cathode assembly described in J3] or K3] above.

[0148] M3] The battery described in L3 above, wherein the battery is a lithium battery.

[0149] A4] A method for forming a cathode composition according to any one of A]-V2] above, the method comprising mixing at least components a and b.

[0150] [B4] According to the method described in [A4] above, the method further includes mixing at least components a, b and c.

[0151] C4] According to the method described in B4], the method further includes mixing at least components a, b, c and d.

[0152] According to the method described in C4], the method further includes mixing at least components a, b, c, d, and e.

[0153] E4] The method according to any one of A4]-D4] above, wherein the mixing is at ≥1000 rpm, or ≥1200 rpm, or ≥1400 rpm, or ≥1600 rpm, or ≥1800 rpm, or ≥2000 rpm And / or Perform at a speed of ≤5000rpm, or ≤4500rpm, or ≤4000rpm, or ≤3500rpm, or ≤3000rpm.

[0154] F4] A method of forming a cathode, the method comprising applying the cathode composition described in any one of A]-V2] above onto a flat surface of a metal foil to form a coated foil.

[0155] G4] According to the method described in F4 above, the metal of the metal foil is selected from aluminum, aluminum alloy, copper, copper alloy, further selected from aluminum or copper, and further selected from aluminum.

[0156] H4] According to the method described in F4] or G4] above, wherein the metal has a diameter of ≥10µm, or ≥12µm, or ≥14µm. And / or Thickness ≤25µm, or ≤22µm, or ≤20µm, or ≤18µm, or ≤16µm.

[0157] According to any one of the methods described above, the coated foil is heat-treated and further heat-treated to evaporate the solvent, thereby forming an active layer on the metal foil.

[0158] J4] According to the method described in I4 above, the coated foil is heated to ≥50°C, or ≥55°C, or ≥60°C, or ≥65°C, or ≥70°C, or ≥75°C, or ≥80°C. And / or Heat treatment shall be performed at temperatures of ≤120℃, ≤115℃, ≤110℃, ≤105℃, ≤100℃, ≤95℃, ≤90℃, or ≤85℃.

[0159] [K4] A method of forming a cathode assembly, the method comprising compacting at least one cathode as described in any one of [A3]-I3] above under pressure.

[0160] L4] According to the method described in K4 above, the method includes compacting at least two cathodes.

[0161] M4] According to the method described in K4] or L4] above, wherein the pressure is ≥5.0MT (millitor), or ≥10MT, or ≥15MT, or ≥20MT, or ≥22MT, or ≥24MT, or ≥26MT And / or ≤40MT, or ≤38MT, or ≤36MT, or ≤34MT, or ≤32MT, or ≤30MT, or ≤28MT.

[0162] [N4] A method of forming a battery, the method comprising inserting the cathode assembly described in [J3] or [K3] into an electrolyte.

[0163] According to the method described above, the battery is a lithium battery.

[0164] experiment

[0165] The reagents are listed in Table 1, and the cathode compositions are shown in Table 2.

[0166]

[0167] Preparation of cathode composition (LFP paste)

[0168] The viscosity of LFP slurry is highly sensitive to moisture. Therefore, before preparing the cathode composition (slurry), each component except NMP is dried in an oven at 80°C under air circulation for 24 hours. NMP is dried at room temperature using a 5A molecular sieve to remove trace amounts of water.

[0169] The slurry preparation is described in the following steps: 1) PVDF (2.0 g) is added to NMP (18 g), and the resulting mixture is heat-treated in an oven set to 50°C until the PVDF is completely dissolved, forming a "PVDF / NMP" solution; 2) Super P (SP, 0.060 g), PVP K30 (PVP, 0.006 g), and NMP (1.194 g) are mixed in a high-speed mixer (SPEEDMIXERDAC). 1) Mix at 3000 rpm for three minutes to form a “SP / PVP / NMP” mixture; 3) Add LFP (6.000 g) and NMP (0.940 g) to the above “SP / PVP / NMP” mixture, and mix the resulting mixture in a high-speed mixer at 3000 rpm for three minutes to form a “LFP / SP / PVP / NMP” mixture; 4) Add “PVDF / NMP” solution (1.800 g) to the above “LFP / SP / PVP / NMP” mixture, and mix the resulting mixture in a high-speed mixer at 2000 rpm for two minutes, and then mix for another two minutes to form a cathode composition precursor; 5) Add the corresponding amount of dispersant (0.012 g) to the above cathode composition precursor according to Table 2 above, and mix the slurry at 2000 rpm for three minutes to form a cathode composition. Note that, as a comparative control, 0.012 g of NMP was added to the cathode composition precursor, and the slurry was mixed at 2000 rpm for three minutes to form a control cathode composition (see CE1). The viscosity of each cathode composition was examined.

[0170] Viscosity of the cathode composition

[0171] The viscosity of each cathode composition (LFP slurry) was measured using a BROOKFIELD CAP 2000+ viscometer. Specifically, 0.5 mL of the cathode composition was placed under the rotor (#10) and kept at 22°C under ambient atmosphere. During the viscosity measurement, the rotor was rotated at a rate of 50 rpm. The cathode composition was held at 22°C for 30 seconds, and then the rotor motor was started. The viscosity data was displayed after 30 seconds as the rotor rotated. One viscosity measurement was performed for each cathode composition. The results are shown below. Figure 1 middle.

[0172] Corrosion Research

[0173] Each dispersant (0.2 g, piperazine, HEP, or Di-HEP) was added to water (19.8 g), and the resulting mixture was stirred in a high-speed mixer at 2000 rpm for three minutes to ensure complete dissolution of the dispersant. The resulting dispersant solution is "1% by weight dispersant" based on the weight of the solution. Next, LFP particles (0.2 g) were added to the dispersant solution, and the resulting slurry was shaken and stored at room temperature (21°C–23°C) under ambient atmosphere for one week. After storage, the slurry was filtered to remove the LFP particles. The Fe cation concentration of the filtrate was examined (corrosion study).

[0174] For corrosion studies, the Fe cation concentration in each filtrate was measured using a Perkin Elmer OPTIMA 5300DV as follows. 1 g of filtrate was added to a 50 ml volumetric flask and diluted to the 50 ml mark with 5% (w / w) aqueous solution of HNO3 to form the test solution. The test solution was weighed, thoroughly mixed, and the Fe cation concentration was analyzed under the following instrument conditions: a) RF power: 1.3 kW; b) Gas flow rates: Plasma gas – 15 L / min, Assist gas – 0.2 L / min, Nebulizer gas – 0.80 L / min; c) Sample delivery – Pump flow rate; d) Flow rate: 1.50 ml / min; e) Observation distance – 15.0 mm; and f) Plasma viewing angle – Axial. The results are shown in Table 3 below.

[0175]

[0176] Summary of Results

[0177] The viscosity of each cathode composition is shown in Figure 1The cathode composition containing AMP (CE2) exhibits a relatively low viscosity, lower than the control cathode composition CE1. For the cathode compositions containing piperazine (CE3) and HEP (CE4), the viscosity of the LFP slurry increased by 35.9% and 13.9% respectively relative to the viscosity of CE1. This indicates that the LFP particles in cathode compositions CE3 and CE4 are poorly dispersed compared to CE2. The cathode composition IE1 containing Di-HEP shows a viscosity decrease of 12.2% relative to CE1 and an 8.4% decrease relative to the viscosity of CE2. These results indicate that cathode composition IE1 has better dispersibility than CE2.

[0178] Corrosion is another important issue, as the degradation of LFP leads to a decline in the performance of the battery cathode. Literature studies indicate that LFP corrodes in acidic environments, releasing Fe cations into the electrolyte within the battery. For piperazine and its derivatives, the active hydrogen (NH) on the ring structure can also contribute to an acidic environment. In this paper, Fe cation concentration was used to characterize the corrosion performance of each dispersant. As shown in Table 3, piperazine produced the highest amount of corrosion (4.4 ppm Fe) compared to HEP and Di-HEP. Both HEP and Di-HEP showed significantly lower corrosion amounts, at 1.7 ppm Fe and 1.6 ppm Fe, respectively. These values ​​indicate that the overall corrosion is negligible. Therefore, cathode compositions containing Di-HEP can be used to form cathodes exhibiting negligible corrosion. Furthermore, such cathode compositions will have reduced viscosity compared to cathode compositions containing AMP, piperazine, or HEP.

Claims

1. A cathode composition comprising at least the following components a) and b): a) at least one lithium phosphate compound, b) At least one dispersant selected from structure 1 below: R1 and R2 are each independently C1-C6 alkylene groups.

2. The cathode composition according to claim 1, wherein the cathode composition is a slurry.

3. The cathode composition according to claim 1 or claim 2, wherein component b is selected from structure 1b) as shown below: , where n is an integer from 1 to 6.

4. The cathode composition according to any one of claims 1 to 3, wherein component a is selected from lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, or combinations thereof.

5. The cathode composition according to claim 4, wherein component a is lithium iron phosphate.

6. The cathode composition according to any one of claims 1 to 5, wherein the component b is present in an amount of 0.05% to 1.00% by weight based on the weight of the cathode composition.

7. The cathode composition according to any one of claims 1 to 6, wherein the weight ratio of component a to component b is 150 to 700.

8. The cathode composition according to any one of claims 1 to 7, wherein the cathode composition further comprises a solvent as component c.

9. The cathode composition according to claim 8, wherein the solvent (component c) is N-methyl-2-pyrrolidone (NMP).

10. The cathode composition according to claim 8 or claim 9, wherein the weight ratio of component a to component c is 1.30 to 2.

00.

11. The cathode composition according to any one of claims 1 to 10, wherein the cathode composition further comprises at least one conductive agent as component d.

12. The cathode composition according to any one of claims 1 to 11, wherein the cathode composition further comprises at least one binder as component e.

13. The cathode composition according to any one of claims 1 to 12, wherein the sum of components a and b is present in an amount of 40.0% to 80.0% by weight, based on the weight of the cathode composition.

14. The cathode composition according to any one of claims 1 to 13, wherein the sum of components a, b and c is present in an amount of 80.0% to 100.0% by weight, based on the weight of the cathode composition.

15. The cathode composition according to any one of claims 1 to 14, wherein the sum of components a, b, c and d is present in an amount of 85.00% to 99.50% by weight, based on the weight of the cathode composition.

16. A cathode comprising an active layer formed of the cathode composition of any one of claims 1 to 15.

17. The cathode of claim 16, wherein the cathode further comprises a metal foil.

18. A cathode assembly comprising at least one cathode as described in claim 16 or claim 17.

19. A battery comprising the cathode assembly of claim 18.

20. A method for forming a cathode composition according to any one of claims 1 to 15, the method comprising mixing at least components a and b.

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