Battery cathode comprising an intrinsically conductive polymer

Abstract

Provided herein are improved lithium-ion battery cathodes comprising intrinsically conductive polymers (ICPs), such as polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA). Lithium-ion battery cathodes utilizing intrinsically conductive polymers, such as compared to battery cathodes prepared using conventional non-conductive polymers, can exhibit higher electrical conductivity and charge density.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 600,907, filed November 20, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a battery cathode having an improved composition, such as a lithium-ion battery cathode. Background Technology

[0004] Lithium-ion batteries have gained widespread adoption due to their high energy density, long cycle life, and relatively low cost compared to other battery technologies. They are widely used in a variety of applications and industries, including portable electronic devices, electric vehicles, renewable energy storage systems, and many other fields.

[0005] In a typical implementation, a lithium-ion battery includes a cathode, an anode, a separator, and an electrolyte. The electrolyte carries positively charged lithium ions from the anode to the cathode through the separator, and vice versa. The movement of lithium ions generates free electrons in the anode, which can be used to generate an electric current.

[0006] Since the early 1990s, various battery cathode compositions have been commercialized, including lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMnO4), lithium iron phosphate (LFP or LiFePO4), lithium nickel cobalt aluminum oxide (NCA), and nickel manganese cobalt (NMC). These materials are inherently particulate and have poor conductivity, resulting in low power density and limitations on charge / discharge current density to avoid fires.

[0007] Currently, battery cathodes are typically prepared by formulating difficult-to-process lithium metal oxide (LMO) powder into a carbon-containing insulating polymer resin (binder) to enhance the conductivity of the resulting cathode. Current battery designs require particle-to-particle contact (percolation) to achieve conductivity. This necessitates a high loading of LMO in the binder, which leads to brittle electrode films and failure.

[0008] There is a need in the art for a battery cathode with improved conductivity that provides enhanced power and energy density when incorporated into existing lithium-ion battery designs. Summary of the Invention

[0009] In one aspect, this document provides a lithium-ion battery cathode that may include one or more of the following components: a cathode matrix comprising a lithium compound; a conductive polymer component comprising at least one conductive polymer; an insulating polymer component comprising one or more insulating polymer resins; and a conductive reinforcing component comprising one or more conductive reinforcing agents.

[0010] This document also provides a composition comprising core-shell particles, wherein the core-shell particles comprise: a core layer comprising at least one alkali metal compound; and a conductive polymer layer comprising at least one conductive polymer.

[0011] This document also provides a core-shell particle comprising: a core layer comprising at least one alkali metal compound; and a conductive polymer layer comprising PANI-DNNSA. Preferably, the core-shell particle comprises the core layer, and the amount of the core layer is from about 20 wt% to about 80 wt% of the total particle.

[0012] This article also provides a method for preparing core-shell particles, the method comprising: providing a solid particulate material comprising at least one alkali metal compound; preparing a coating composition comprising at least one conductive polymer dispersed in an organic solvent; dispersing the solid particulate material in the coating composition to form coated particles; separating the coated particles from the coating composition; and drying the coated particles at an elevated temperature.

[0013] Other purposes and features will be apparent in part and indicated in part below. Attached Figure Description

[0014] Figure 1 A schematic diagram of a lithium-ion battery 100 is shown, comprising a cathode substrate 102, a conductive polymer component 104, an electrolyte 106, and an anode 108.

[0015] Figure 2 A cross-sectional view of a core-shell particle 200 is depicted, the core-shell particle 200 including a core layer 202 encapsulated by a conductive polymer layer 204.

[0016] Figure 3 It is a superimposed graph of cyclic voltammetry readings performed on a glassy carbon electrode as described in Example 3.

[0017] Figure 4 It is a superimposed graph of cyclic voltammetry readings performed on a glassy carbon electrode as described in Example 4.

[0018] Figure 5 It is a superimposed graph of cyclic voltammetry readings taken on the gold electrode as described in Example 4.

[0019] Figure 6 The electrochemical resistance and capacitance of different conductive polymers as described in Example 4 are depicted.

[0020] Figure 7 It is a superimposed graph of cyclic voltammetry readings taken on a black iron wire as described in Example 5. Detailed Implementation

[0021] This paper presents an improved lithium-ion battery cathode comprising an intrinsically conductive polymer (ICP). Lithium-ion battery cathodes utilizing intrinsically conductive polymers exhibit higher conductivity and charge density, for example, compared to battery cathodes prepared using conventional non-conductive polymers.

[0022] For example, this document provides processable intrinsically conductive polymers (ICPs) for coating LMO or LFP particles to enhance conductivity and lithium-ion transport. The methods provided herein may include, for example, adding ICPs to insulating polymer binder resins to enhance and improve the conductivity of electrode composite structures.

[0023] This document also provides core-shell particles comprising: a core layer comprising an alkali metal compound; and a conductive polymer layer comprising at least one conductive polymer. The core-shell particles can be used, for example, as a battery cathode. Specifically, when the alkali metal compound is a lithium compound, the core-shell particles can be used as a lithium-ion battery cathode, as further detailed below.

[0024] lithium-ion battery cathode

[0025] This document provides a lithium-ion battery cathode that may comprise, substantially comprise, or comprise one or more of the following components: (1) a cathode matrix comprising a lithium compound, (2) a conductive polymer component comprising at least one conductive polymer, (3) an insulating polymer component comprising one or more insulating polymer resins, and (4) a conductive reinforcing component comprising one or more conductive reinforcing agents. Each of these components is further described in detail below.

[0026] cathode substrate

[0027] A lithium-ion battery cathode may include a cathode substrate. For example, the composition may include particulate metal compounds useful in the construction of the battery cathode.

[0028] The cathode substrate may include, for example, lithium compounds. Non-limiting examples of cathode substrates include lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMnO4), lithium iron phosphate (LFP or LiFePO4), lithium nickel cobalt aluminum oxide (NCA), and nickel manganese cobalt (NMC). A preferred cathode substrate is lithium iron phosphate (LFP).

[0029] The cathode substrate may include lithium compounds in the form of solid particles. For example, in a typical embodiment, the solid particles may have an average particle size of about 1 nm to about 1000 nm. In a typical embodiment, the solid particles may, for example, have a D90 particle size of about 10 nm to about 6000 nm.

[0030] For example, the solid particles may have an average particle size of at least about 0.5 nm, at least about 1 nm, at least about 2 nm, at least about 5 nm, at least about 10 nm, at least about 25 nm, at least about 50 nm, or at least about 100 nm. Conversely, the solid particles may have an average particle size, for example, not greater than about 2000 nm, not greater than about 1500 nm, not greater than about 1000 nm, not greater than about 900 nm, not greater than about 800 nm, not greater than about 700 nm, not greater than about 600 nm, or not greater than about 500 nm. The solid particles may have an average particle size falling within the range defined by any two of the values ​​listed above. As a non-limiting example, the solid particles may have an average particle size of about 1 nm to about 2000 nm, about 1 nm to about 1000 nm, or about 10 nm to about 500 nm.

[0031] The solid particles may have a D90 particle size of at least about 5 nm, at least about 10 nm, at least about 20 nm, at least about 50 nm, at least about 100 nm, at least about 250 nm, at least about 500 nm, or at least about 1000 nm. Conversely, the solid particles may have a D90 particle size of, for example, not greater than about 20,000 nm, not greater than about 15,000 nm, not greater than about 10,000 nm, not greater than about 9,000 nm, not greater than about 8,000 nm, not greater than about 7,000 nm, not greater than about 6,000 nm, or not greater than about 5,000 nm. The solid particles may have a D90 particle size falling within the range defined by any two of the values ​​listed above. As a non-limiting example, the solid particles may have a D90 particle size of about 10 nm to about 10,000 nm, about 100 nm to about 10,000 nm, or about 1,000 nm to about 6,000 nm.

[0032] The lithium-ion battery cathode may include the cathode substrate, and the amount of the cathode substrate is, for example, from about 1 wt% to about 90 wt% of the entire composition.

[0033] For example, a lithium-ion battery cathode may include the cathode substrate, and the amount of the cathode substrate is at least about 1 wt%, at least about 5 wt%, at least about 10 wt%, at least about 20 wt%, at least about 30 wt%, at least about 40 wt%, at least about 50 wt%, or at least about 60 wt% of the total composition. Conversely, a lithium-ion battery cathode may include the cathode substrate, and the amount of the cathode substrate is, for example, at most about 90 wt%, at most about 85 wt%, at most about 80 wt%, at most about 75 wt%, or at most about 70 wt% of the total composition. A lithium-ion battery cathode may include the cathode substrate, and the amount of the cathode substrate falls within the range defined by any two of the values ​​listed above. As a non-limiting example, a lithium-ion battery cathode may include the cathode substrate, and the amount of the cathode substrate is from about 1 wt% to about 90 wt%, from about 20 wt% to about 80 wt%, or from about 40 wt% to about 70 wt% of the total composition.

[0034] conductive polymer

[0035] Lithium-ion battery cathodes may include conductive polymer components, comprising one or more conductive polymers. In the lithium-ion battery cathodes provided herein, conductive polymers are used to bind the cathode matrix (which may be in the form of bulk particles as discussed above) together without reducing the overall conductivity and charge density of the cathode as is the case with non-conductive polymers traditionally used for this purpose.

[0036] Unbound by any particular theory, it is believed that using intrinsically conductive polymers can improve the conductivity and charge density of a battery cathode by providing a conductive network between the matrix particles. This conductive network effectively utilizes the charge capacity of all the particles, transferring electrons back and forth between the matrix particles as lithium ions are extracted and inserted into them. Advantageously, compared to conventional battery cathodes, the matrix particles do not need to be in physical contact with each other and can operate below the percolation limit.

[0037] In a preferred embodiment, the conductive polymer is soluble in an organic solvent. For example, the conductive polymer is soluble in organic solvents selected from the group consisting of xylene, toluene, cymene, and ethers.

[0038] Non-limiting examples of suitable conductive polymers include polyaniline, such as polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA), polyaniline camphor sulfonic acid (PANI-CSA), polyaniline dodecylbenzene sulfonic acid (PANI-DBSA), polyaniline polystyrene sulfonic acid (PANI-PSSA); polyvinyl dioxythiophene polystyrene sulfonic acid (PEDOT-PSSA); polypyrrole; and combinations thereof. For example, the conductive polymer component may include PANI-DNSSA.

[0039] The conductive polymer component may include an alkali metal-doped conductive polymer. As used herein, the term "alkali metal-doped conductive polymer" refers to a conductive polymer in which at least a portion of the hydrogen atoms naturally present in the polymer have been replaced by alkali metal cations. For example, the alkali metal-doped conductive polymer may be a lithium-doped conductive polymer in which at least a portion of the hydrogen atoms naturally present in the polymer have been replaced by lithium cations. Alkali metal-doped conductive polymers can be prepared by immersing the conductive polymer in an alkali metal hydroxide (e.g., lithium hydroxide).

[0040] Non-limiting examples of suitable alkali metal-doped conductive polymers include alkali metal-doped polyaniline, such as alkali metal-doped PANI-DNNSA, alkali metal-doped PANI-CSA, alkali metal-doped PANI-DBSA, alkali metal-doped PANI-PSSA; alkali metal-doped PEDOT-PSSA; alkali metal-doped polypyrrole; and combinations thereof. For example, the conductive polymer component may include lithium-doped conductive polymers selected from the group consisting of lithium-doped PANI-DNNSA, lithium-doped PANI-CSA, lithium-doped PANI-DBSA, lithium-doped PANI-PSSA, lithium-doped PEDOT-PSSA, lithium-doped polypyrrole, and combinations thereof. As a non-limiting example, the conductive polymer component may include lithium-doped PANI-DNSSA.

[0041] As an illustrative example, the polymer component may include lithium-doped PANI-DNSSA, which comprises DNSSA and aniline in a molar ratio of about 6:4, as shown in the following exemplary structure.

[0042]

[0043] General Formula I

[0044] For alkali metal-doped conductive polymers, the optimal doping amount depends on the concentration of conductive groups present in the polymer. For example, with PANI-DNNSA, the molar ratio of DNNSA to aniline in the polymer is controlled during polymer synthesis and can be in the range of about 1 to 3. An excess of DNNSA is typically present to maintain polymer solubility. When PANI-DNSSA reacts with LiOH, the DNNSA units are neutralized by the hydroxide, leaving the lithium salt of the DNNSA units. Therefore, if PANI-DNSSA with an initial DNNSA / aniline molar ratio of 2:1 is completely neutralized using LiOH, the resulting lithium-doped PANI-DNSSA has a ratio of 2 moles of LiDNNS (lithium dinonylnaphthalenesulfonate) / moles of aniline.

[0045] Conductive polymers, particularly lithium-doped conductive polymers, can be both electronically and lithium-ion conductive. For example, in the cathode of a lithium-ion battery using lithium-ion polymers (LFPs) as the cathode substrate, lithium-doped conductive polymers promote lithium-ion transport to the LFP substrate. When the battery is charging, lithium ions move out of the LFP substrate; when the battery is discharging, lithium ions move into the LFP substrate. Additionally, lithium-doped conductive polymers can act as a barrier against negatively charged substances from the electrolyte that could contaminate the cathode substrate and reduce cycle life. Lithium-doped conductive polymers can also inhibit dendrite growth.

[0046] The lithium-ion battery cathode may include the conductive polymer component, and the amount of the conductive polymer component is, for example, at least about 0.1 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 2 wt%, at least about 3 wt%, at least about 4 wt%, at least about 5 wt%, or at least about 10 wt% of the total composition. Conversely, the lithium-ion battery cathode may include the conductive polymer component, and the amount of the conductive polymer component is, for example, at most about 30 wt%, at most about 25 wt%, at most about 20 wt%, at most about 15 wt%, or at most about 10 wt% of the total composition. The lithium-ion battery cathode may include the conductive polymer component, and the amount of the conductive polymer component falls within the range defined by any two of the values ​​listed above. As a non-limiting example, the lithium-ion battery cathode may include the conductive polymer component, and the amount of the conductive polymer component is about 0.1 wt% to about 25 wt%, about 1 wt% to about 25 wt%, or about 5 wt% to about 25 wt% of the total composition.

[0047] A lithium-ion battery cathode may, for example, include the conductive polymer component, and the weight ratio of the conductive polymer component to the cathode substrate is about 1:1 or less. For example, the weight ratio of the conductive polymer component to the cathode substrate may be at most about 1:1, at most about 0.9:1, at most about 0.8:1, at most about 0.7:1, at most about 0.6:1, at most about 0.5:1, or at most about 0.4:1. Conversely, a lithium-ion battery cathode may include the conductive polymer component, and the weight ratio of the conductive polymer component to the cathode substrate is at least about 0.01:1, at least about 0.05:1, at least about 0.1:1, at least about 0.15:1, at least about 0.2:1, or at least about 0.25:1. A lithium-ion battery cathode may include the conductive polymer component and the cathode substrate, and the weight ratio of the conductive polymer component to the cathode substrate falls within the range defined by any two of the values ​​listed above. As a non-limiting example, a lithium-ion battery cathode may include the conductive polymer component and the cathode substrate, wherein the weight ratio of the conductive polymer component to the cathode substrate is about 0.01:1 to about 1:1, about 0.1:1 to about 1:1, or about 0.2:1 to about 0.6:1.

[0048] Insulating polymer

[0049] A lithium-ion battery cathode may include an insulating polymer component, which includes one or more insulating polymer resins. In the lithium-ion battery cathodes provided herein, the insulating polymer resin component may be selectively used in combination with the conductive polymer component as described above. For example, it may be desirable to incorporate the insulating polymer resin component into the battery cathode to increase the flexibility of the cathode structure.

[0050] Non-limiting examples of suitable insulating polymer resins include polyvinylidene fluoride, polytetrafluoroethylene (PTFE), styrene-butadiene block copolymer (SBR), sodium carboxymethyl cellulose (CMC), polyacrylate, ethylene-propylene-diene rubber (EPDM), and mixtures thereof. For example, the insulating polymer component may include polyvinylidene fluoride.

[0051] The lithium-ion battery cathode may include the insulating polymer resin component, and the amount of the insulating polymer resin component is, for example, from about 0.1 wt% to about 25 wt% of the total composition.

[0052] The lithium-ion battery cathode may include the insulating polymer component, and the amount of the insulating polymer component is, for example, at least about 0.1 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 2 wt%, at least about 3 wt%, at least about 4 wt%, at least about 5 wt%, or at least about 10 wt% of the total composition. Conversely, the lithium-ion battery cathode may include the insulating polymer component, and the amount of the insulating polymer component is, for example, at most about 30 wt%, at most about 25 wt%, at most about 20 wt%, at most about 15 wt%, or at most about 10 wt% of the total composition. The lithium-ion battery cathode may include the insulating polymer component, and the amount of the insulating polymer component falls within the range defined by any two of the values ​​listed above. As a non-limiting example, the lithium-ion battery cathode may include the insulating polymer component, and the amount of the insulating polymer component is about 0.1 wt% to about 25 wt%, about 1 wt% to about 25 wt%, or about 5 wt% to about 25 wt% of the total composition.

[0053] Conductivity enhancer

[0054] The cathode of a lithium-ion battery may also include a conductivity-enhancing component, which includes one or more conductivity-enhancing agents. Conductivity-enhancing agents include secondary dopants that allow polymer chain extension and increase π-stacking and chain-to-chain electron transitions.

[0055] Non-limiting examples of conductivity enhancers that can be added to improve conductivity include sulfonyl diphenol (SDP), m-cresol, p-toluenesulfonamide, p-toluenesulfonic acid, lithium stearate, and combinations thereof.

[0056] The lithium-ion battery cathode may include one or more of the aforementioned conductive enhancers, and the amount of the one or more conductive enhancers is from about 0.1 wt% to about 10 wt% of the total composition.

[0057] For example, a lithium-ion battery cathode may include the conductivity-enhancing component, and the amount of the conductivity-enhancing component is, for example, at least about 0.1 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 2 wt%, at least about 3 wt%, at least about 4 wt%, or at least about 5 wt% of the total composition. Conversely, a lithium-ion battery cathode may include the conductivity-enhancing component, and the amount of the conductivity-enhancing component is, for example, at most about 10 wt%, at most about 9 wt%, at most about 8 wt%, at most about 7 wt%, at most about 6 wt%, or at most about 5 wt% of the total composition. A lithium-ion battery cathode may include the conductivity-enhancing component, and the amount of the conductivity-enhancing component falls within the range defined by any two of the values ​​listed above. As a non-limiting example, a lithium-ion battery cathode may include the conductivity-enhancing component, and the amount of the conductivity-enhancing component is from about 0.1 wt% to about 10 wt%, from about 1 wt% to about 10 wt%, or from about 1 wt% to about 5 wt% of the total composition.

[0058] Lithium-ion batteries

[0059] This article also provides a lithium-ion battery that includes a lithium-ion battery cathode as generally described above.

[0060] For example, Figure 1 A schematic diagram of a lithium-ion battery 100 is shown. Typically, the lithium-ion battery 100 includes a cathode substrate 102, a conductive polymer component 104, an electrolyte 106, and an anode 108.

[0061] Typically, the cathode substrate 102 can be selected as detailed above. For example... Figure 1 As shown, the cathode substrate 102 includes lithium iron phosphate (LFP).

[0062] Typically, the conductive polymer component 104 can be selected as detailed above. For example... Figure 1 As shown, the conductive polymer component 104 includes lithium-doped PANI.

[0063] Electrolyte 106 may generally comprise any suitable electrolyte composition known to those skilled in the art. Non-limiting examples of electrolyte salts suitable for lithium-ion batteries include lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium bis(oxalate)borate, lithium difluoro(oxalate)borate, lithium trifluoromethanesulfonate, and lithium bis(fluorosulfonyl)imide. Figure 1 As shown, electrolyte 106 comprises lithium hexafluorophosphate. Electrolyte 106 may include the electrolyte salt, and the concentration of the electrolyte salt is, for example, from about 0.1 mol / L to about 10 mol / L, more typically from about 0.5 mol / L to about 2 mol / L, or most typically from about 1 mol / L.

[0064] Optionally, the electrolyte 106 may also include a solvent component, which includes one or more solvents. Non-limiting examples of suitable solvents include carbonate solvents, such as ethylene carbonate, dimethyl carbonate, propylene carbonate, methyl ethyl carbonate, and combinations thereof.

[0065] Anode 108 may typically comprise any suitable material known for use as an anode in a lithium-ion battery. For example, anode 108 may comprise graphite.

[0066] Core-shell particles

[0067] This document also provides a composition comprising core-shell particles, wherein the core-shell particles comprise, substantially comprise, or comprise of: (1) a core layer comprising at least one alkali metal compound, and (2) a conductive polymer layer comprising at least one conductive polymer. Optionally, the conductive polymer layer may further comprise one or more of: (a) an insulating polymer component comprising one or more insulating polymer resins, and (b) a conductive reinforcing component comprising one or more conductive reinforcing agents. The core-shell particles provided herein can, for example, be used as alkali metal battery cathodes (e.g., lithium-ion battery cathodes) as generally described above.

[0068] Now turn to the attached diagram. Figure 2 A cross-sectional view of a core-shell particle 200 is shown. The particle 200 includes a core layer 202, which is encapsulated by a conductive polymer layer 204.

[0069] like Figure 2 As shown, the conductive polymer layer 204 encapsulates the core layer 202 and forms a continuous interface across the entire surface of the core layer 202. In an alternative embodiment, the core-shell particles may include one or more additional layers between the conductive polymer layer 204 and the core layer 202, and / or one or more additional layers outside the conductive polymer layer 204.

[0070] The core layer 202 comprises at least one alkali metal compound. Non-limiting examples of alkali metal compounds include lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium titanium oxide, sodium nickel chloride, sodium cobalt oxide, sodium iron phosphate, potassium iron phosphate, lithium vanadium oxide, lithium nickel oxide, sodium manganese oxide, lithium manganese nickel oxide, lithium copper oxide, sodium vanadium oxide, lithium titanium oxide, sodium titanium oxide, lithium manganese titanium oxide, lithium nickel manganese oxide, lithium iron silicate, lithium manganese silicate, lithium iron borate, lithium manganese borate, lithium iridium, rhodium oxide, platinum oxide, and mixtures thereof. Preferably, the alkali metal compound comprises a lithium compound, which may be selected as described above regarding the general lithium-ion battery cathode substrate. For example, the alkali metal compound may include lithium iron phosphate.

[0071] Typically, the core layer 202 will account for approximately 1 wt% to approximately 90 wt% of the total weight of the core-shell particle 200.

[0072] For example, core-shell particles 200 may include the core layer 202, and the amount of the core layer 202 is at least about 1 wt%, at least about 5 wt%, at least about 10 wt%, at least about 20 wt%, at least about 30 wt%, at least about 40 wt%, at least about 50 wt%, or at least about 60 wt% of the total particle. Conversely, core-shell particles 200 may include the core layer 202, and the amount of the core layer 202 is, for example, at most about 90 wt%, at most about 85 wt%, at most about 80 wt%, at most about 75 wt%, or at most about 70 wt% of the total particle. Core-shell particles 200 may include the core layer 202, and the amount of the core layer 202 falls within the range defined by any two of the values ​​listed above. As a non-limiting example, the core-shell particle 200 may include the core layer 202, and the amount of the core layer 202 is about 1 wt% to about 90 wt%, about 20 wt% to about 80 wt%, or about 40 wt% to about 70 wt% of the total particle.

[0073] The conductive polymer layer 204 includes at least one conductive polymer, which may be selected as described above regarding the general lithium-ion battery cathode substrate. For example, the conductive polymer layer 204 may include at least one conductive polymer selected from the group consisting of: polyaniline, such as polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA), polyaniline camphor sulfonic acid (PANI-CSA), polyaniline dodecylbenzene sulfonic acid (PANI-DBSA), polyaniline polystyrene sulfonic acid (PANI-PSSA); polyvinyl dioxythiophene polystyrene sulfonic acid (PEDOT-PSSA); polypyrrole; and combinations thereof. As a further example, the conductive polymer layer 204 may include an alkali metal-doped conductive polymer as detailed above.

[0074] The conductive polymer layer 204 may optionally include an insulating polymer component, comprising one or more insulating polymer resins, which may be selected as described above. For example, the conductive polymer layer 204 may optionally include polyvinylidene fluoride.

[0075] The conductive polymer layer 204 may optionally include a conductivity-enhancing component, which includes one or more conductivity-enhancing agents. For example, the conductive polymer layer 204 may optionally include at least one conductivity-enhancing agent selected from the group consisting of: sulfonyl diphenol (SDP), m-cresol, p-toluenesulfonamide, p-toluenesulfonic acid, lithium stearate, and combinations thereof.

[0076] The conductive polymer layer 204 may include the conductive polymer component, and the concentration of the conductive polymer component relative to the total weight of the conductive polymer layer 204 is at least about 10 wt%. For example, the conductive polymer layer 204 may include the conductive polymer component, and the concentration of the conductive polymer component is at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 35 wt%, or at least about 40 wt%. Conversely, the conductive polymer layer 204 may include the conductive polymer component, and the concentration of the conductive polymer component is at most about 80 wt%, at most about 75 wt%, at most about 70 wt%, at most about 65 wt%, at most about 60 wt%, at most about 55 wt%, or at most about 50 wt%. The conductive polymer layer 204 may include the conductive polymer component, and the concentration of the conductive polymer component falls within the range defined by any two of the values ​​listed above. For example, the conductive polymer layer 204 may include the conductive polymer component, and the concentration of the conductive polymer component is from about 10 wt% to about 80 wt%, or from about 20 wt% to about 70 wt%.

[0077] The conductive polymer layer 204 may include the insulating polymer component, and the concentration of the insulating polymer component relative to the total weight of the conductive polymer layer 204 is at least about 10 wt%. For example, the conductive polymer layer 204 may include the insulating polymer component, and the concentration of the insulating polymer component is at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 35 wt%, or at least about 40 wt%. Conversely, the conductive polymer layer 204 may include the insulating polymer component, and the concentration of the insulating polymer component is at most about 60 wt%, at most about 55 wt%, at most about 50 wt%, at most about 45 wt%, or at most about 40 wt%. The conductive polymer layer 204 may include the insulating polymer component, and the concentration of the insulating polymer component falls within the range defined by any two of the values ​​listed above. For example, the conductive polymer layer 204 may include the insulating polymer component, and the concentration of the insulating polymer component is from about 10 wt% to about 50 wt%, or from about 20 wt% to about 40 wt%.

[0078] The conductive polymer layer 204 may include a conductive reinforcing component, and the concentration of the conductive reinforcing component relative to the total weight of the conductive polymer layer 204 is at least about 0.5 wt%. For example, the conductive polymer layer 204 may include the conductive reinforcing component, and the concentration of the conductive reinforcing component is at least about 1 wt%, at least about 1.5 wt%, at least about 2 wt%, at least about 3 wt%, at least about 4 wt%, or at least about 5 wt%. Conversely, the conductive polymer layer 204 may include the conductive reinforcing component, and the concentration of the conductive reinforcing component is at most about 15 wt%, at most about 10 wt%, at most about 9 wt%, at most about 8 wt%, at most about 7 wt%, at most about 6 wt%, at most about 5 wt%, at most about 4 wt%, at most about 3 wt%, or at most about 2 wt%. The conductive polymer layer 204 may include the conductive reinforcing component, and the concentration of the conductive reinforcing component falls within the range defined by any two of the values ​​listed above. For example, the conductive polymer layer 204 may include the conductive reinforcing component, and the concentration of the conductive reinforcing component is from about 0.5 wt% to about 10 wt%, or from about 1 wt% to about 5 wt%.

[0079] The composition may include core-shell particles having an average particle size of about 1 nm to about 1000 nm. In a typical embodiment, the solid particles may, for example, have a D90 particle size of about 10 nm to about 6000 nm.

[0080] For example, the composition may include core-shell particles having an average particle size of at least about 0.5 nm, at least about 1 nm, at least about 2 nm, at least about 5 nm, at least about 10 nm, at least about 25 nm, at least about 50 nm, or at least about 100 nm. Conversely, the composition may include core-shell particles having an average particle size, for example, not greater than about 2000 nm, not greater than about 1500 nm, not greater than about 1000 nm, not greater than about 900 nm, not greater than about 800 nm, not greater than about 700 nm, not greater than about 600 nm, or not greater than about 500 nm. The composition may include core-shell particles having an average particle size falling within the range defined by any two of the values ​​listed above. As a non-limiting example, the composition may include core-shell particles having an average particle size of about 1 nm to about 2000 nm, about 1 nm to about 1000 nm, or about 10 nm to about 500 nm.

[0081] The composition may include core-shell particles having a D90 diameter of at least about 5 nm, at least about 10 nm, at least about 20 nm, at least about 50 nm, at least about 100 nm, at least about 250 nm, at least about 500 nm, or at least about 1000 nm. Conversely, the composition may include core-shell particles having a D90 diameter, for example, not greater than about 20,000 nm, not greater than about 15,000 nm, not greater than about 10,000 nm, not greater than about 9000 nm, not greater than about 8000 nm, not greater than about 7000 nm, not greater than about 6000 nm, or not greater than about 5000 nm. The composition may include core-shell particles having a D90 diameter falling within the range defined by any two of the values ​​listed above. As a non-limiting example, the composition may include core-shell particles having a D90 diameter of about 10 nm to about 10,000 nm, about 100 nm to about 10,000 nm, or about 1,000 nm to about 6,000 nm.

[0082] Methods for preparing core-shell particles

[0083] This document also provides a method for preparing core-shell particles, particularly for preparing core-shell particles as detailed above. The method may include one or more of the following steps: (1) providing a solid particulate material comprising at least one alkali metal compound; (2) preparing a coating composition comprising at least one conductive polymer dispersed in an organic solvent; (3) dispersing the solid particulate material in the coating composition to form coated particles; (4) separating the coated particles from the coating composition; and (5) removing excess solvent from the coated particles.

[0084] The solid particulate material preferably has the particle size distribution described above regarding the cathode substrate. The alkali metal may be selected as described above regarding the core-shell particles.

[0085] The coating composition may include any solvent in which the at least one conductive polymer has sufficient solubility. For example, the solvent may include water (e.g., when the conductive polymer is PEDOT-PSS). The solvent may include organic solvents. Non-limiting examples of suitable organic solvents include NMP (N-methyl-2-pyrrolidone), N,N-dimethylacetamide (DMAc), xylene, toluene, umbelliferone, and ethers. The at least one conductive polymer may be selected as detailed above.

[0086] The solid particulate material can be dispersed in the coating composition using any suitable technique known to those skilled in the art. For example, the solid particulate material can be dispersed by mixing (e.g., using a high-shear mixer).

[0087] The coated particles can be separated from the coating composition using any suitable technique known to those skilled in the art. For example, the coated particles can be separated from the coating composition by filtration. Optionally, the coated particles can be washed with a solvent (e.g., isopropanol) before filtration. Depending on the size of the coated particles, the filtration can be performed using an ultrafiltration membrane having a pore size of about 0.3 nm to about 10 nm. As a further alternative, the particles can be separated from the coating composition using an ultracentrifuge.

[0088] The coated particles can be dried at elevated temperatures to remove excess solvent. For example, the coated particles can be dried at temperatures of at least about 40°C, at least about 50°C, at least about 60°C, at least about 70°C, or at least about 80°C. Typically, the coated particles are dried at temperatures not exceeding about 100°C. The particles can be dried for a sufficient time to substantially remove any excess solvent, typically in the range of about 1 hour to about 24 hours (e.g., about 1 hour to about 4 hours).

[0089] The coated particles can be dried at reduced pressures. For example, the coated particles can be dried at pressures less than about 1000 mbar, less than about 800 mbar, less than about 600 mbar, less than about 500 mbar, less than about 420 mbar, less than about 400 mbar, less than about 350 mbar, or less than about 300 mbar. In some embodiments, the coated particles can be dried at very low pressures, less than about 250 mbar, less than about 200 mbar, less than about 150 mbar, or even less than about 100 mbar. As a non-limiting example, the coated particles can be dried at pressures from about 10 mbar to about 500 mbar, or about 200 to 400 mbar, or about 10 to 100 mbar.

[0090] The following embodiments illustrate various aspects of the present invention. It should be understood that these embodiments are merely illustrative of certain implementations of the invention and do not constitute a limitation on the scope of the invention as defined by the appended claims.

[0091] After a detailed description of this disclosure, it will be apparent that modifications and variations may be made without departing from the scope of the claims.

[0092] Example

[0093] The following non-limiting embodiments are provided to further illustrate this disclosure.

[0094] Example 1: Lithium iron polyaniline phosphate (LFP)

[0095] This embodiment illustrates the use of an ICP coating to provide a more conductive LFP structure with improved conductivity, charge / discharge stability, and reduced charge transfer resistance.

[0096] Here, polyaniline dinonylnaphthalenesulfonic acid (PANI-DNNSA, a highly soluble form of polyaniline) is used to formulate a cathode with higher conductivity, providing a more stable structure during electrode discharge (lithium-ion insertion) and charging (lithium-ion extraction). PANI-DNNSA is a cation-dominant transport system and promotes lithium-ion transport during both charging and discharging as it undergoes oxidation and reduction.

[0097] detail:

[0098] LFP powder was dispersed in a dilute PANI-DNNSA solution in an organic solvent (xylene, toluene, cymene, or ether) using a high-shear mixer. After a period of time, the coated particles were separated from the solvent by filtration and then subjected to drum drying to remove the solvent. The coated particles were then rinsed with a solvent (isopropanol, ethanol, or acetone) to remove excess dopant (DNNSA). After further drying under vacuum, the electrical conductivity of the powder was measured (method described in Carbon 40 (2002) 2801–2815).

[0099] At this point, various amounts of the coated powder were dispersed in a resin solution (10 wt% polyvinylidene fluoride in NMP). The formulation was coated onto a current collector electrode (glassy carbon, gold, or copper electrode) and dried. Electrochemical measurements were performed in a three-electrode configuration with a lithium reference electrode and a platinum counter electrode in an ethylene carbonate (EC) / dimethyl carbonate (DMC) solvent containing 0.1 M lithium hexafluorophosphate (LiPF6). Energy density, power density, and cycle life were measured and compared with controls.

[0100] Example 2: Lithium metal oxide (LMO) cathode

[0101] In this embodiment, the aim is to form a more stable LMO structure with improved conductivity, charge-discharge stability and reduced charge transfer resistance.

[0102] In the efforts described herein, LiMn2O4 will be evaluated as a base LMO because it is more environmentally friendly and less expensive than other LMOs. The proposed techniques will be applicable to other LMOs, such as LiCoO2.

[0103] detail:

[0104] LiMn2O4 (supplied by American Elements) was dispersed in PANI-DNNSA toluene. Then, other additives such as sulfonyl diphenol (SDP) and lithium stearate were added to the formulation to enhance conductivity. The formulation could then be used as a coating or incorporated into a graphite / PVDF resin solution (10 wt% Ketjen Black (KB, Lion Corporation) and 10 wt% polyvinylidene fluoride (PVDF, Canrd Corporation) in NMP).

[0105] At this point, various amounts of the coated powder were dispersed in a resin solution (10 wt% polyvinylidene fluoride in NMP). The formulation was coated onto a current collector electrode (glassy carbon, gold, or copper electrode) and dried. Electrochemical measurements were performed in a three-electrode configuration with a lithium reference electrode and a platinum counter electrode in an ethylene carbonate (EC) / dimethyl carbonate (DMC) solvent containing 0.1 M lithium hexafluorophosphate (LiPF6). Energy density, power density, and cycle life were measured and compared with controls.

[0106] Note that the process described in Examples 1 and 2 above will be applicable to other active lithium metal oxide anode materials, including lithium cobalt oxide, lithium cobalt, lithium nickel aluminum oxide, lithium nickel manganese cobalt, and lithium manganese, iron or cobalt silicates.

[0107] Example 3: Preparation of lithium-doped PANI-DNSSA

[0108] PANI-DNNSA was dissolved in cymene to a concentration of approximately 5% w / w. Ten drops of this solution were added to 1 ml of water in a vial containing 100 mg of lithium hydroxide. The solution was shaken for a few seconds, after which the green PANI-DNNSA solution turned blue and phase separated into a clear lower aqueous layer and a blue upper cymene layer containing lithium-doped PANI-DNNSA. The upper layer was coated onto a glassy carbon electrode and allowed to air dry for 3 days. After this period, cyclic voltammetry was run on the electrode in a 2.8% aqueous lithium nitrate solution (shown as...). Figure 3 ).

[0109] like Figure 3 As shown, curve A displays the oxidation wave of the lithium PANI-DNNSA coating, compared with curve B (for the glassy carbon electrode).

[0110] Example 4: Electrochemical evaluation of lithium-doped PANI-DNSSA

[0111] A 0.5 μL solution of 50% PANI-DNNSA in toluene was applied to both the glassy carbon electrode and the gold electrode. These electrodes were then dried at ambient temperature for 24 hours, followed by cyclic voltammetry and impedance spectroscopy experiments in 2.8% lithium nitrate.

[0112] The electrode was evaluated for each of the following sequential chemical treatments: (1) no treatment; (2) immersion in isopropanol for 10 seconds; and (3) immersion in 1 M LiOH solution for 10 minutes.

[0113] The superimposed graph of cyclic voltammetry is shown in Figure 4 Curve A is the cyclic voltammogram of the untreated PANI film on GC, curve B is the film treated with IPA, and curve C is the lithium-doped PANI-DNNSA curve. Although PANI-DNNSA was neutralized in potassium hydroxide solution for 10 minutes, the film still exhibited electroactivity due to the promotion of lithium-ion transport.

[0114] like Figure 5 As shown, the coated gold electrode behaves similarly to the glassy carbon electrode.

[0115] The electrochemical impedance of each treatment was also evaluated, and the results are plotted on... Figure 6 As shown in the table, lithium-doped polymers exhibit very similar resistance and capacitance characteristics to non-lithium-doped polymer coatings.

[0116] Example 5: Electrochemical evaluation of lithium-doped PANI-DNSSA

[0117] A 0.125 mm black iron wire (low carbon steel) was abraded with No. 000 steel wool, wiped with a 70% isopropanol aqueous solution, and immersed in boiling 10% phosphoric acid for 10 minutes. After rinsing with water, the wire was cycled ten times in 2.8% lithium nitrate solution with the potential relative to SCE between -0.5 and 0.6 V to generate lithium iron oxide (LiFeO4) on the surface of the wire.

[0118] The iron wire was then immersed in a 5% PANI solution in xylene and air-dried. Cyclic voltammetry was then performed on the PANI-DNNSA-coated LiFeO4 iron wire in 2.8% lithium nitrate. Figure 7 (Curve A in the figure). The coated iron wire was then immersed in a 70% isopropanol solution for 10 seconds and air-dried. Cyclic voltammetry was then performed on the sample. Figure 7 Curve B in the middle. Figure 7 Curve C shown represents an iron wire (control) that has been cleaned as described above and immersed in boiling phosphoric acid. The red and blue curves show a significant increase in current between 0 and 0.6 volts, demonstrating an increase in cathode current compared to the control.

[0119] When describing elements of this disclosure or its preferred embodiments, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that other elements may be present in addition to those listed.

[0120] In view of the above, it will be seen that several objectives of this disclosure have been achieved and other favorable results have been obtained.

[0121] Since various changes can be made to the products and methods described above without departing from the scope of this disclosure, it is intended that all content contained in the above description should be interpreted in an illustrative rather than restrictive sense.

Claims

1. A lithium-ion battery cathode, comprising: (1) Cathode substrate including lithium compounds; and (2) A conductive polymer component including at least one conductive polymer; The cathode comprises the conductive polymer component and the cathode substrate in a weight ratio of about 0.01:1 to about 1:

1.

2. The cathode according to claim 1, wherein, The cathode substrate comprises lithium compounds selected from the group consisting of: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, and combinations thereof.

3. The cathode according to claim 1, wherein, The cathode substrate comprises lithium iron phosphate.

4. The cathode according to any one of claims 1 to 3, wherein, The cathode comprises the cathode substrate in an amount of at least about 10 wt% of the entire composition.

5. The cathode according to any one of claims 1 to 3, wherein, The conductive polymer component comprises conductive polymers selected from the group consisting of: polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA), polyaniline camphor sulfonic acid (PANI-CSA), polyaniline dodecylbenzene sulfonic acid (PANI-DBSA), polyaniline polystyrene sulfonic acid (PANI-PSSA), polyethylene dioxythiophene polystyrene sulfonic acid (PEDOT-PSSA), polypyrrole, and combinations thereof.

6. The cathode according to claim 5, wherein, The conductive polymer component includes PANI-DNNSA.

7. The cathode according to any one of claims 1 to 3, wherein, The conductive polymer component includes an alkali metal-doped conductive polymer.

8. The cathode according to any one of claims 1 to 6, wherein, The cathode comprises the conductive polymer component in an amount of at least about 1 wt% of the total composition.

9. The cathode according to any one of claims 1 to 7, wherein, The cathode comprises the conductive polymer component and the cathode substrate in a weight ratio of about 0.1:1 to about 1:

1.

10. The cathode according to claim 9, wherein, The cathode substrate comprises a lithium compound in the form of solid particles with an average particle size of about 1 nm to about 1000 nm.

11. The cathode according to claim 9 or 10, wherein, The cathode substrate comprises a lithium compound in the form of solid particles with a D90 particle size of about 10 nm to about 6000 nm.

12. The cathode according to any one of claims 1 to 11, wherein, The cathode also includes an insulating polymer component, which comprises one or more insulating polymer resins.

13. The cathode according to claim 12, wherein, The insulating polymer component includes polyvinylidene fluoride.

14. The cathode according to claim 12 or 13, wherein, The cathode comprises the insulating polymer component in an amount of about 0.1 wt% to about 25 wt% of the total composition.

15. The cathode according to any one of claims 1 to 14, wherein, The cathode further includes a conductivity-enhancing component, which includes one or more conductivity-enhancing agents.

16. The cathode according to claim 15, wherein, The conductivity-enhancing component includes at least one conductivity enhancer selected from the group consisting of: sulfonyl diphenol (SDP), m-cresol, p-toluenesulfonamide, p-toluenesulfonic acid, lithium stearate, and combinations thereof.

17. The cathode according to claim 15 or 16, wherein, The cathode comprises the conductivity-enhancing component in an amount of about 0.1 wt% to about 10 wt% of the total composition.

18. A composition comprising core-shell particles, wherein, The core-shell particles include: (1) A core layer comprising at least one alkali metal compound; and (2) A conductive polymer layer comprising at least one conductive polymer.

19. The composition according to claim 18, wherein, The core layer comprises at least one alkali metal compound selected from the group consisting of: lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium titanium oxide, sodium nickel chloride, sodium cobalt oxide, sodium iron phosphate, potassium iron phosphate, lithium vanadium oxide, lithium nickel oxide, sodium manganese oxide, lithium manganese nickel oxide, lithium copper oxide, sodium vanadium oxide, lithium titanium oxide, sodium titanium oxide, lithium manganese titanium oxide, and lithium nickel manganese oxide.

20. The composition according to claim 19, wherein, The core layer comprises lithium iron phosphate.

21. The composition according to claim 18, wherein, The conductive polymer layer comprises at least one conductive polymer selected from the group consisting of: polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA), polyaniline camphor sulfonic acid (PANI-CSA), polyaniline dodecylbenzene sulfonic acid (PANI-DBSA), polyaniline polystyrene sulfonic acid (PANI-PSSA), polyethylene dioxythiophene polystyrene sulfonic acid (PEDOT-PSSA), and polypyrrole (PPy).

22. The composition according to claim 21, wherein, The conductive polymer layer includes PANI-DNNSA.

23. The composition according to any one of claims 18 to 22, wherein, The average particle size of the core-shell particles is about 1 nm to about 2000 nm.

24. The composition according to any one of claims 18 to 23, wherein, The core-shell particles have a D90 diameter of approximately 10 nm to approximately 10,000 nm.

25. The composition according to any one of claims 18 to 24, wherein, The core-shell particles comprise the core layer in an amount of about 20 wt% to about 80 wt% of the total particles.

26. A core-shell particle, comprising: (1) A core layer comprising at least one alkali metal compound selected from the group consisting of: lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium titanium oxide, sodium nickel chloride, sodium cobalt oxide, sodium iron phosphate, potassium iron phosphate, lithium vanadium oxide, lithium nickel oxide, sodium manganese oxide, lithium manganese nickel oxide, lithium copper oxide, sodium vanadium oxide, lithium titanium oxide, sodium titanium oxide, lithium manganese titanium oxide, and lithium nickel manganese oxide; and (2) A conductive polymer layer, wherein the conductive polymer layer comprises PANI-DNNSA, The core layer is said to comprise about 20 wt% to about 80 wt% of the total particles.

27. The core-shell particle according to claim 26, wherein, The core layer comprises lithium iron phosphate.

28. A method for preparing core-shell particles, the method comprising: (1) Providing a solid particulate material, said solid particulate material comprising at least one alkali metal compound; (2) Prepare a coating composition comprising at least one conductive polymer dispersed in an organic solvent; (3) Disperse the solid particulate material in the coating composition to form coated particles; (4) Separating the coated particles from the coating composition; and (5) Dry the coated particles at an elevated temperature.

29. The method according to claim 28, wherein, The solid particulate material comprises at least one alkali metal compound selected from the group consisting of: lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium titanium oxide, sodium nickel chloride, sodium cobalt oxide, sodium iron phosphate, potassium iron phosphate, lithium vanadium oxide, lithium nickel oxide, sodium manganese oxide, lithium manganese nickel oxide, lithium copper oxide, sodium vanadium oxide, lithium titanium oxide, sodium titanium oxide, lithium manganese titanium oxide, and lithium nickel manganese oxide.

30. The method according to claim 29, wherein, The solid particulate material includes lithium iron phosphate.

31. The method according to claim 28, wherein, The coating composition comprises at least one conductive polymer selected from the group consisting of: polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA), polyaniline camphor sulfonic acid (PANI-CSA), polyaniline dodecylbenzene sulfonic acid (PANI-DB-SA), polyaniline polystyrene sulfonic acid (PANI-PSSA), polyethylene dioxythiophene polystyrene sulfonic acid (PEDOT-PSSA), and polypyrrole (PPy).

32. The method according to claim 31, wherein, The coating composition includes PANI-DNNSA.

33. The method according to claim 28, wherein, The coating composition includes an organic solvent selected from the group consisting of xylene, toluene, cymene, and ether.

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