Conductive prime coat material and preparation method thereof, current collector and energy storage device

Abstract

The invention discloses a conductive prime coat material and a preparation method thereof, a current collector and an energy storage device, the conductive prime coat material comprises a porous material and a poly (3, 4-ethylenedioxythiophene) layer which is formed by carrying out confinement in-situ oxidative polymerization on 3, 4-ethylenedioxythiophene and is attached in pore channels and / or on the surface of the porous material, and the poly (3, 4-ethylenedioxythiophene) layer is formed by carrying out confinement in-situ oxidative polymerization on the poly (3, 4-ethylenedioxythiophene) layer and the poly (3, 4-ethylenedioxythiophene) layer. The poly (3, 4-ethylenedioxythiophene) layer and the porous material are connected through strong interaction, the porous material is an ionic conductive phase, and the poly (3, 4-ethylenedioxythiophene) layer is an electronic conductive phase. In the conductive prime coat material, 3, 4-ethylenedioxythiophene (EDOT) monomers enter the pore channels and / or the surface of the porous material, a poly 3, 4-ethylenedioxythiophene (PEDOT) network attached in the pore channels and / or the surface of the porous material is formed after confinement in-situ polymerization, and a three-dimensional network with continuous electron transmission channels and continuous ion transmission channels is formed. Therefore, the interface impedance and the diffusion impedance are obviously reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage devices, in particular to a conductive primer material, a preparation method thereof, a current collector and an energy storage device. BACKGROUND

[0002] New energy storage devices including lithium-ion batteries and sodium-ion batteries, supercapacitors, etc., have a wide application prospect in the field of energy storage devices due to their high power density and long cycle life. The electrode sheet is the core part of the above-mentioned energy storage devices, and the traditional electrode sheet includes a current collector and an active material layer, which is prepared by coating the active material on the current collector after being prepared into an active slurry.

[0003] With the continuous progress of high-performance energy storage devices, dry electrode technology has attracted increasing attention due to its potential in high-energy-density devices. The dry electrode technology respectively prepares a dry active film and a current collector with a primer layer, and then laminates and hot-composites the two to fix them together to obtain an electrode sheet. However, due to the lack of solvent wetting effect of the dry electrode active layer, several key problems are exposed in practical application: insufficient contact between the active layer and the current collector, resulting in large interface contact resistance; discontinuous electron transport path, causing significant polarization of the device under high rate conditions; at the same time, the lack of continuous ion transport channels makes it difficult for electrolyte to fully penetrate into the interior of the active layer; in high temperature and high humidity environment (such as double 85 test), the interface side reaction is intensified, further increasing the resistance.

[0004] In order to solve the above problems, the current industry generally adopts technical means including introducing conductive polymers (such as PEDOT: PSS) into the primer layer to enhance the electronic conductivity, adding metal organic frameworks (MOF) / covalent organic frameworks (COF) or mesoporous materials to optimize the ion transport capacity, and building a composite conductive coating by physically mixing the two. However, these methods are essentially simple mixing systems, which have many limitations: lack of chemical bonding between the electronic conductive phase and the ionic conductive phase, resulting in large interface charge transfer resistance; it is difficult to build a three-dimensional interpenetrating electronic and ionic co-conductive network; the pore structure cannot be effectively embedded in the electron transport path; at the same time, the phase separation phenomenon will significantly increase the ion diffusion resistance.

[0005] Therefore, there is an urgent need to develop a new material that can realize continuous electron transport channels and continuous ion transport channels, thereby significantly reducing the interface impedance and diffusion impedance. SUMMARY

[0006] Therefore, it is necessary to provide a conductive primer material that can solve the above problems.

[0007] In addition, it is also necessary to provide a preparation method of the conductive primer material, a current collector using the conductive primer material, and an energy storage device comprising the current collector.

[0008] A conductive primer material includes a porous material and a poly(3,4-ethylenedioxythiophene) layer formed by confined in-situ oxidative polymerization of 3,4-ethylenedioxythiophene, which is attached to the pores and / or surface of the porous material. The poly(3,4-ethylenedioxythiophene) layer and the porous material are connected by strong interaction. The porous material is an ion-conducting phase, and the poly(3,4-ethylenedioxythiophene) layer is an electronically conductive phase.

[0009] In one embodiment, the porous material is selected from at least one of mesoporous silica, MOF, and COF; The pore size of the porous material is 0.3 nm to 5 nm.

[0010] In one embodiment, the MOF is selected from at least one of MIL-100(Fe), ZIF-8, UiO-66, and HKUST-1; The COF is selected from at least one of TpPa-SO3H, TpPa-NH2, COF-300, and COF-316.

[0011] In one embodiment, the mass ratio of the poly(3,4-ethylenedioxythiophene) layer to the porous material is 1~8:2~9.

[0012] In one embodiment, the porous material has -SO3H and -SO3H on its pores and / or surface. 3- At least one of the following groups: -NH2 and -COOH; The strong interaction is selected from at least one of electrostatic interaction, hydrogen bonding, π–π stacking interaction and metal coordination.

[0013] A method for preparing the above-mentioned conductive primer material includes the following steps: A porous material and 3,4-ethylenedioxythiophene are mixed evenly in a dispersant, so that the 3,4-ethylenedioxythiophene enters the pores of the porous material or is adsorbed on the surface of the porous material, resulting in a dispersion. An oxidant is added to the dispersion to cause the 3,4-ethylenedioxythiophene to undergo confined in-situ oxidative polymerization, thereby forming a poly(3,4-ethylenedioxythiophene) layer attached to the pores and / or surface of the porous material. After separation, the desired conductive primer material is obtained.

[0014] In one embodiment, during the operation of uniformly mixing the porous material and 3,4-ethylenedioxythiophene in a dispersant, the mass ratio of the porous material to 3,4-ethylenedioxythiophene is 1:0.1~5, and the dispersant is water or a mixed solution of water and ethanol with a volume ratio of 1~9:1. In the process of adding an oxidant to the dispersion to cause the 3,4-ethylenedioxythiophene to undergo confined in-situ oxidative polymerization, the oxidant is selected from at least one of FeCl3, APS, H2O2 and Cu(ClO4)2, the reaction temperature is 0~50℃, and the reaction time is 0.5h~12h.

[0015] In one embodiment, the method for preparing the conductive primer further includes, after obtaining the desired conductive primer through separation, performing the following operation: immersing the conductive primer in a weak acid solution, wherein the concentration of the weak acid solution is 0.01 mol / L to 0.5 mol / L, and the solute in the weak acid solution is selected from at least one of acetic acid and citric acid.

[0016] A current collector includes a substrate and a base coating layer attached to the substrate, wherein the material of the base coating layer includes the aforementioned conductive base coating material, and the mass percentage of the conductive base coating material to the base coating layer is 70wt% to 99wt%.

[0017] An energy storage device includes the aforementioned current collector.

[0018] In the conductive primer material of the present invention, 3,4-ethylenedioxythiophene (EDOT) monomer enters the pores and / or surface of the porous material, and after confined in-situ polymerization, a poly(3,4-ethylenedioxythiophene) (PEDOT) network is formed attached to the pores and / or surface of the porous material, forming a three-dimensional network with continuous electron transport channels and continuous ion transport channels, thereby significantly reducing interfacial impedance and diffusion impedance.

[0019] In specific embodiments, the conductive primer material of the present invention is applied to the primer layer of the current collector, and the interface impedance and diffusion impedance of the electrode sheet / battery using the current collector are significantly reduced. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] in: Figure 1 This is a flowchart of a method for preparing a current collector according to one embodiment. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention discloses a conductive primer material according to one embodiment, comprising a porous material and a poly(3,4-ethylenedioxythiophene) layer formed by confined in-situ oxidative polymerization of 3,4-ethylenedioxythiophene, which is attached to the pores and / or surface of the porous material. The poly(3,4-ethylenedioxythiophene) layer and the porous material are connected by strong interaction. The porous material is an ion-conducting phase, and the poly(3,4-ethylenedioxythiophene) layer is an electronically conductive phase.

[0024] In the conductive primer material of the present invention, 3,4-ethylenedioxythiophene (EDOT) monomer enters the pores and / or surface of the porous material, and after confined in-situ polymerization, a poly(3,4-ethylenedioxythiophene) (PEDOT) layer is formed attached to the pores and / or surface of the porous material, forming a three-dimensional network with continuous electron transport channels and continuous ion transport channels, thereby significantly reducing interfacial impedance and diffusion impedance.

[0025] In specific embodiments, the conductive primer material of the present invention is applied to the primer layer of the current collector, and the interface impedance and diffusion impedance of the electrode sheet / battery using the current collector are significantly reduced.

[0026] Specifically, in this embodiment, PEDOT is directionally grown along the pore wall surface of the porous material to form a branched network.

[0027] Preferably, in this embodiment, the strong interaction is selected from at least one of electrostatic interaction, hydrogen bonding, π–π stacking interaction and metal coordination.

[0028] Preferably, in this embodiment, the PEDOT layer formed by confined in-situ oxidative polymerization has a nanoscale orientation structure. A nanoscale orientation structure in the PEDOT layer means that, under the confinement of the porous material's pores, the PEDOT segments exhibit a preferential orientation growth trend along the pore walls or pore axis at the nanoscale. This nanoscale orientation structure is beneficial for improving the π-conjugated continuity between PEDOT segments, reducing scattering and jumping resistance during electron transport, thereby enhancing the electronic conductivity and rate stability of the conductive primer material.

[0029] Preferably, in this embodiment, there is no macroscopic phase separation structure in the conductive primer material. Since PEDOT is formed in situ within the pores of the porous material, the electronically conductive phase and the ionicly conductive phase interpenetrate each other at the nanoscale, thus no observable phase separation structure is formed at the macroscopic scale.

[0030] Preferably, in this embodiment, the porous material has a regular pore structure, and the porous material is selected from at least one of mesoporous silica, MOF and COF.

[0031] Preferably, in this embodiment, the pore size of the porous material is 0.3 nm to 5 nm.

[0032] More preferably, in this embodiment, the specific surface area of ​​the porous material is 200 m² / g to 3000 m² / g.

[0033] Specifically, in this embodiment, the MOF is selected from at least one of MIL-100(Fe), ZIF-8, UiO-66 and HKUST-1.

[0034] Specifically, in this embodiment, COF is selected from at least one of TpPa-SO3H, TpPa-NH2, COF-300, and COF-316.

[0035] Preferably, in this embodiment, the mass ratio of the poly(3,4-ethylenedioxythiophene) layer to the porous material is 1~8:2~9. By controlling the mass ratio of the poly(3,4-ethylenedioxythiophene) layer to the porous material within the range of 1~8:2~9, sufficient ion diffusion space can be maintained while ensuring continuous electron conduction, thereby achieving a synergistic reduction in interfacial impedance and ion diffusion impedance.

[0036] Specifically, in this embodiment, the conductive primer material has an ion diffusion resistance of less than 1.5 Ω at 10 Hz.

[0037] Preferably, in this embodiment, the porous material has -SO3H and -SO3 groups inside the pores and / or on its surface. - At least one of the following groups: -NH2 and -COOH.

[0038] -SO3H, -SO3 introduced into the pores and / or surface of porous materials - At least one group selected from -NH2 and -COOH is used to improve the affinity between 3,4-ethylenedioxythiophene monomer and porous materials, enhance the enrichment and confinement effect of monomer in the pores, and stabilize the adhesion state of poly(3,4-ethylenedioxythiophene) layer in the pores and on the pore wall surface through non-covalent strong interactions such as hydrogen bonding, electrostatic interaction and π-conjugation interaction during confined in-situ oxidative polymerization, thereby facilitating the construction of continuous and stable electron transport channels and ion transport channels.

[0039] Specifically, -SO3H, -SO3 - It exhibits strong polarity and high hydrophilicity, enabling it to form dipole-dipole interactions and electrostatic attraction with the thiophene ring and ethylenedioxy group of EDOT. Furthermore, during polymerization, -SO3H acts as a charge compensation site (similar to the role of PSS), helping to stabilize the positive charge of PEDOT and increase the proportion of conductive states; while -SO3... - It has good ionophilicity, which helps electrolyte ions wet and migrate in the pores.

[0040] Specifically, -NH2 is a polar group that can form hydrogen bonds and dipole interactions with EDOT; EDOT is more likely to nucleate and grow along the pore wall in amino-rich regions, which is conducive to the formation of a "PEDOT branched network extending along the pore wall"; -NH2 does not participate in the Schiff base reaction here, but only serves as an auxiliary group for interface regulation and confined polymerization.

[0041] -COOH (carboxyl group) provides surface charge and hydrogen bond network, improving the dispersion stability of porous materials in water or water / ethanol systems; -COOH can form hydrogen bonds and dipole-dipole interactions with EDOT or PEDOT, reducing the risk of PEDOT falling off after polymerization.

[0042] Combination Figure 1 The present invention also discloses a method for preparing the above-mentioned conductive primer material according to one embodiment, comprising the following steps: S10. Mix the porous material and 3,4-ethylenedioxythiophene in a dispersant until they are homogeneous, so that 3,4-ethylenedioxythiophene enters the pores of the porous material or is adsorbed on the surface of the porous material to obtain a dispersion.

[0043] Preferably, in S10, the mass ratio of the porous material to 3,4-ethylenedioxythiophene is 1:0.1~5.

[0044] Preferably, in S10, the dispersant is water or a mixed solution of water and ethanol with a volume ratio of 1 to 9:1.

[0045] Preferably, step S10 further includes pretreatment of the porous material to impart -SO3H and -SO3H to the pores and / or surface of the porous material. 3- Operations involving at least one of the following groups: -NH2 and -COOH.

[0046] S20. An oxidant is added to the dispersion obtained in S10 to cause 3,4-ethylenedioxythiophene to undergo confined in-situ oxidative polymerization, thereby forming a poly(3,4-ethylenedioxythiophene) layer attached to the pores and / or surface of the porous material. After separation, the desired conductive primer material is obtained.

[0047] Preferably, in S20, the oxidant is selected from at least one of FeCl3, APS, H2O2 and Cu(ClO4)2, the reaction temperature is 0~50℃, and the reaction time is 0.5h~12h.

[0048] The separation process involves centrifugation and filtration, followed by retaining the solid, washing with water and / or ethanol, and finally drying to achieve separation.

[0049] Preferably, S20 further includes, after obtaining the desired conductive primer material through separation, performing the following operation: immersing the conductive primer material in a weak acid solution, so that the micropores in the conductive primer material expand into a micropore-mesopore composite structure, wherein the concentration of the weak acid solution is 0.01 ~ 0.5 mol / L.

[0050] The solute in the weak acid solution is selected from at least one of acetic acid and citric acid.

[0051] Immersing the conductive primer in a weak acid solution allows for the gentle etching and control of the pore structure of the porous material without disrupting the continuity of the poly(3,4-ethylenedioxythiophene) layer. This causes the original micropores to expand moderately at the pore openings and walls, forming a micropore-mesopore composite pore structure. This composite pore structure maintains the stability of the porous material framework while effectively reducing pore tortuosity and increasing the effective ion transport cross-sectional area. This allows electrolyte ions to enter and penetrate the interior of the conductive primer more quickly, further reducing ion diffusion resistance and improving the electrochemical performance of the conductive primer under high-rate conditions.

[0052] The present invention also discloses a current collector according to one embodiment, comprising a substrate and a base coating layer attached to the substrate, wherein the material of the base coating layer comprises the above-mentioned conductive base coating material, and the mass percentage of the conductive base coating material to the base coating layer is 70wt% to 99wt%.

[0053] Preferably, the substrate can be copper foil, aluminum foil, etched copper foil, or etched aluminum foil.

[0054] Preferably, the material of the base coating also includes conductive carbon material, and the proportion of conductive carbon material in the mass of the base coating is 1wt% to 30wt%.

[0055] Specifically, the conductive carbon material is selected from at least one of carbon black, conductive graphite, carbon nanotubes, and graphene.

[0056] Preferably, the thickness of the base coating is 1μm to 5μm.

[0057] Preferably, in this embodiment, the primer coating layer can be obtained by applying a primer slurry onto the substrate and drying it.

[0058] More preferably, in this embodiment, the solid content of the primer slurry is 5 to 30 wt%.

[0059] More preferably, in this embodiment, the coating can be applied by gravure coating, doctor blade coating, spraying, or roll-to-roll coating.

[0060] More preferably, in this embodiment, the drying temperature is 50°C to 150°C, and the drying step includes segmented heating at 50°C to 150°C.

[0061] The current collector of this invention can be used in dry electrode technology. It is laminated with a dry active film and then thermally bonded together to obtain an electrode sheet.

[0062] The electrode sheet obtained in this way has a contact resistance at the electrode interface reduced by at least 30%, an ion diffusion impedance reduced by at least 50%, and after aging at 85 °C / 85%RH for 1000 h, its interface resistance increases by less than 20%.

[0063] The present invention also discloses an embodiment of an energy storage device including the above-described current collector.

[0064] Specifically, the aforementioned energy storage devices include supercapacitors, secondary batteries, and lithium-ion hybrid capacitors.

[0065] Secondary batteries can be lithium-ion batteries, sodium-ion batteries, etc.

[0066] The following are specific examples.

[0067] Example 1: EDOT is confined and in-situ polymerized within the channels of MSNs to form PEDOT@MSN dual-channel material.

[0068] (1) Material preparation Electronically conductive monomer: EDOT (3,4-ethylenedioxythiophene, purity ≥99%). Oxidizing agent: Ferric chloride (FeCl3·6H2O); Ion-conducting phase: Aminated mesoporous silica nanospheres (Shanghai EPRUIBiotech, porous SiO2 microspheres 2-001-3-100; MSN, pore size 3.0±0.2 nm, specific surface area 850 m² / g, amino density 1.2 mmol / g, wherein the amino groups provide hydrogen bonding / electrostatic interaction with PEDOT and promote EDOT adsorption). Conductive carbon material: Ketjen Black EC-600JD (BET: 1300 m² / g).

[0069] (2) Preparation of PEDOT@MSN by confined in-situ polymerization 2.0 g of aminated MSNs were dispersed in 50 mL of deionized water and sonicated for 30 min. 0.5 g of EDOT monomer was added, and the mixture was stirred under nitrogen for 2 h to allow EDOT to fully penetrate the pores. 1.5 g of FeCl3 (dissolved in 20 mL of water) was added dropwise under ice bath conditions, controlling the temperature at 0–5 °C. The reaction proceeded for 6 h, during which EDOT within the pores underwent directional polymerization under oxidant confinement, forming a PEDOT inner wall branched network. After separating the solid, the mixture was washed repeatedly with water and ethanol, and then vacuum dried to obtain the conductive primer material PEDOT@MSN.

[0070] (3) Preparation of primer slurry In a high-speed shearing machine, PEDOT@MSN:Ketjen Black was premixed at a mass ratio of 70:30. An appropriate amount of water was added to adjust the solid content to 8 wt%. Then, 0.5 wt% DMSO (to improve the conductivity of PEDOT) and 0.1 wt% Triton X-100 (to improve wetting) were added, and the rotation speed was increased to 10,000 rpm. The mixture was dispersed for 1 h to obtain the primer slurry.

[0071] (4) Coating and drying The slurry was coated onto etched aluminum foil (Ra=2.0μm) using a microgravure coating machine, resulting in a wet film thickness of 60μm. It was then dried in a three-zone oven: 90℃ / 60s→110℃ / 90s→130℃ / 60s, forming a base coating with a dry film thickness of approximately 2.5~3.5 μm, thus obtaining a current collector with the base coating.

[0072] (5) Composite with dry active layer The activated carbon (YP-50F): conductive carbon black (SuperP): PTFE were uniformly dry-mixed in a ratio of 93:4:3 (dry basis mass ratio) and rolled into a self-drying active layer. The dry active layer was then hot-pressed onto the current collector with the base coating obtained above at 10 MPa and 80°C to obtain the PEDOT@MSN-base-coated electrode sheet.

[0073] Example 2: EDOT is directionally polymerized in the macropores of MIL-100(Fe), and PEDOT / MOF forms an interpenetrating structure.

[0074] (1) Material preparation Electronically conductive monomer: EDOT (3,4-ethylenedioxythiophene, purity ≥99%). Oxidizing agent: Ferric chloride (FeCl3·6H2O); MOF ion-conducting phase: MIL-100(Fe) (CHEMSOON®, CAS No.: 1195763-37-1), with a pore size of 2.5~8.6 nm (suitable for TEA). + BF4- Multimetallic sites (Fe³) + (Can be used with PSS) - (or EDOT coordination occurs). Conductive carbon material: Super P (2) Confined in-situ polymerization step 2.0 g of MIL-100(Fe) was ultrasonically dispersed in 50 mL of water / ethanol (1:1) solution. 0.6 g of EDOT was added and stirred for 3 h to allow it to enter the macropores. FeCl3 solution (FeCl3:EDOT molar ratio 2.5:1) was added, and the mixture was reacted in an ice bath for 6 h to obtain a conductive primer. Due to the multi-metallic sites of MIL-100(Fe), PEDOT directionally polymerized on the pore walls and passed through Fe³⁺. + -SO3 - Coordination forms a stable interface bond.

[0075] (3) Preparation of primer slurry: PEDOT@MIL-100 : Super P = 80 : 20 by dry weight ratio; subsequent coating and drying are the same as in Example 1.

[0076] Example 3: EDOT is confined and in-situ polymerized within the pores of high specific surface area mesoporous silica to form a highly loaded PEDOT@MSN conductive primer material. (1) Material preparation Electronically conductive monomer: EDOT (3,4-ethylenedioxythiophene, purity ≥99%). Oxidizing agent: Ferric chloride (FeCl3·6H2O); Ion-conducting phase: High specific surface area mesoporous silica nanospheres (MSN, pore size 2.8±0.2 nm, specific surface area 1200 m² / g, without the introduction of additional surface functional groups). Conductive carbon material: Ketjen Black EC-600JD.

[0077] 2) Preparation of PEDOT@MSN by confined in-situ polymerization 2.0 g of high specific surface area MSNs were dispersed in 50 mL of deionized water and sonicated for 30 min. 0.4 g of EDOT monomer was added, and the mixture was stirred at room temperature for 2 h to allow EDOT to enter the mesoporous structure through capillary action. Subsequently, FeCl3 aqueous solution (FeCl3 to EDOT molar ratio of 2:1) was slowly added dropwise under ice bath conditions, controlling the reaction temperature at 0–5 °C, and the reaction was continued for 5 h.

[0078] Within a confined space, EDOT undergoes in-situ oxidative polymerization on the inner wall of the pores, forming a continuous but relatively thin PEDOT inner wall coating layer. After the reaction is complete, the solid is separated, washed with deionized water and ethanol, and vacuum dried to obtain the conductive primer material PEDOT@MSN.

[0079] (3) Preparation and application of primer slurry The primer slurry was prepared according to the dry weight ratio of PEDOT@MSN : Ketjen Black = 75 : 25. The subsequent coating, drying and electrode bonding steps were the same as in Example 1.

[0080] Example 4: EDOT is polymerized in situ within the confined space at the inlet and surface of small-aperture MOF channels to form a dense PEDOT@MOF conductive primer material. (1) Material preparation Electronically conductive monomer: EDOT (3,4-ethylenedioxythiophene, purity ≥99%). Oxidizing agent: Ferric chloride (FeCl3·6H2O); Ion-conducting phase: ZIF-8 (pore size approximately 0.34 nm, BET specific surface area approximately 1600 m² / g). Conductive carbon material: Super P.

[0081] (2) Preparation of PEDOT@ZIF-8 by confined in-situ polymerization 2.0 g of ZIF-8 was ultrasonically dispersed in 60 mL of a deionized water / ethanol mixture (volume ratio 1:1). 0.3 g of EDOT monomer was added, and the mixture was stirred at room temperature for 3 h to enrich EDOT in the pore inlet and adjacent areas. Subsequently, an aqueous FeCl3 solution (FeCl3 to EDOT molar ratio 2.5:1) was added under ice bath conditions at 0–5 °C, and the reaction was carried out for 6 h to induce in-situ oxidative polymerization of EDOT, forming a PEDOT conductive layer covering the pore inlet and surface. After the reaction, the solid was separated, washed with water and ethanol, and vacuum dried to obtain the conductive primer material PEDOT@ZIF-8.

[0082] The obtained PEDOT@ZIF-8 conductive primer was immersed in a 0.05 mol / L acetic acid solution for 10 min at room temperature with gentle stirring. After immersion, the sample was removed, thoroughly washed with deionized water until neutral, and dried under vacuum at 60–80 °C to obtain the weakly acid-treated PEDOT@ZIF-8 conductive primer.

[0083] (3) Preparation and application of primer slurry The primer slurry was prepared according to the dry matter ratio of PEDOT@ZIF-8 : Super P = 80 : 20, and the remaining steps were the same as in Example 1.

[0084] Comparative Example 1: Non-ionic conductive phase (no dual-channel structure) Preparation of primer slurry: In a high-speed shear mill, PEDOT:PSS and Ketjen Black were premixed at a mass ratio of 70:30. An appropriate amount of water was added to adjust the solid content to 8 wt%. Then, 0.5 wt% DMSO (to improve the conductivity of PEDOT) and 0.1 wt% Triton X-100 (to improve wetting) were added, and the speed was increased to 10,000 rpm. The mixture was dispersed for 1 h to obtain the primer slurry.

[0085] The subsequent coating and drying processes were the same as in Example 1.

[0086] Comparative Example 2: No in-situ polymerization was performed, only mechanical mixing was carried out. Preparation of primer slurry: In a high-speed shear mill, PEDOT:PSS, Ketjen Black and MSN (same as in Example 1) were premixed at a mass ratio of 40:20:40. An appropriate amount of water was added to adjust the solid content to 8 wt%. Then, 0.5 wt% DMSO (to improve the conductivity of PEDOT) and 0.1 wt% Triton X-100 (to improve wetting) were added, and the speed was increased to 10,000 rpm. The mixture was dispersed for 1 h to obtain the primer slurry.

[0087] The subsequent coating and drying processes were the same as in Example 1.

[0088] Test case 1. Performance Testing: The performance of the electrode sheets prepared in Examples 1-4 and Comparative Examples 1-2 was tested using the following methods.

[0089] Test method: 1) Interfacial Contact Resistance: A current collector with a conductive undercoat and a dry-formed active layer were composited under a pressure of 8–12 MPa and a temperature of 70–90 °C. The composites were then cut into electrode sheets of uniform area and assembled into a symmetrical electrochemical testing unit. Electrochemical impedance spectroscopy (EIS) was performed on the electrodes using an electrochemical workstation at a constant temperature of 25 ± 2 °C. The test frequency range was 100 kHz to 0.01 Hz, and the AC perturbation voltage amplitude was 5 mV. By fitting the impedance spectrum in the high-frequency region, the impedance component corresponding to the interfacial electron transport process was used as the interfacial contact resistance of the conductive undercoat.

[0090] 2) Ion diffusion impedance: In the above-mentioned symmetrical electrode system, electrochemical impedance spectroscopy was performed under the same test conditions, and the impedance value corresponding to the low-frequency region around 10 Hz was selected as the ion diffusion impedance characterization parameter. This impedance mainly reflects the diffusion behavior of electrolyte ions in the porous substrate material and interface region. All samples were tested under the same electrolyte system and the same temperature conditions to ensure the comparability of the test results.

[0091] 3) Specific capacitance: The prepared electrodes are assembled into a capacitor with a rated capacitance of 3 F, and a constant current charge-discharge test is performed within a specified voltage window. Based on the current and voltage changes and discharge time during the discharge process in the constant current charge-discharge curve, and in conjunction with the mass of the active material in the electrode, the specific capacitance of the capacitor is calculated. A constant ambient temperature is maintained during the test to ensure the comparability of test results for different samples.

[0092] 4) Rate Performance (Capacitance Retention): Under the same electrode system, the 3F capacitor was subjected to constant current charge-discharge tests under different charge-discharge current conditions, namely 0.03 A, 0.15 A, and 0.3 A. The specific capacitance measured under the low current condition (0.03 A) was used as the benchmark value, and the ratio of the specific capacitance under the high current condition (0.3 A) to the benchmark value was calculated as the capacitance retention rate, which was used to evaluate the synergistic stability of the electron and ion transport channels of the conductive primer material under high rate charge-discharge conditions.

[0093] 5) Capacitance retention after 10,000 cycles: The 3 F capacitor was subjected to continuous constant current charge-discharge cycle testing within a voltage window of 0~2.7 V under a constant current condition of 0.03 A. The specific capacitance value during the initial cycle stage and the specific capacitance value after 10,000 charge-discharge cycles were recorded respectively, and the ratio of the two was used as the capacity retention rate after 10,000 cycles. A constant test voltage window and ambient temperature were maintained during the test to eliminate the influence of external factors on the cycle stability results.

[0094] The test results are shown in Table 1 below.

[0095] Table 1: Performance Test Comparison Table Data Analysis: Based on the electrochemical performance test results of the conductive primer materials prepared in Examples 1-4 and Comparative Examples 1 and 2 (Table 1), it can be seen that the present invention, by performing confined in-situ oxidative polymerization within and / or on the surface of porous materials, can construct continuous electron transport channels and ion transport channels without introducing covalent anchoring or pore structure reconstruction methods, thereby significantly improving the interface performance of the conductive primer coating.

[0096] 1. Regarding interfacial contact resistance, Examples 1 and 2 exhibited the lowest interfacial impedance, with interfacial contact resistances of 5.5 mΩ·cm² and 5.8 mΩ·cm², respectively. This is mainly attributed to the enhanced interfacial affinity provided by the aminated mesoporous silica and the metal nodes in MIL-100(Fe), which allow EDOT monomers to be fully enriched within the channels and undergo uniform confined in-situ polymerization, thereby forming a through-hole PEDOT electronically conductive network.

[0097] Example 3 uses high specific surface area mesoporous silica without introduced surface functional groups as the porous material. Its PEDOT mainly relies on the physical confinement of the pores to form the inner wall coating structure. Due to the relatively weak interfacial forces, its interfacial contact resistance is slightly higher than that of Example 1 and Example 2, but still significantly lower than that of the comparative sample, indicating that confined in-situ polymerization still has significant advantages in constructing continuous electron channels.

[0098] 2. Regarding ion diffusion resistance, Examples 1 and 2 exhibited the lowest diffusion resistance due to their moderate pore size and good connectivity. In Example 3, the higher pore volume facilitated electrolyte wetting, but the relatively high pore tortuosity slightly increased the ion migration resistance. Example 4 used a small-pore MOF (ZIF-8) as a porous framework, where PEDOT mainly underwent confined in-situ polymerization at the pore inlets and particle surfaces, forming a dense conductive capping layer. Due to the small pore size of ZIF-8, ions mainly migrated through the pore inlets and intergranular regions, resulting in a slightly higher ion diffusion resistance compared to large-pore MOFs or mesoporous silica systems.

[0099] 3. In terms of rate performance and cycling stability, Examples 1-4 maintained high capacity retention under high scan rate and long cycling conditions, and their overall performance was significantly better than that of the comparative samples. This indicates that the electron-ion dual continuous channel structure constructed by confined in-situ oxidative polymerization can effectively alleviate the polarization problem under high rate conditions.

[0100] The electrochemical performance of the conductive primer was further optimized by introducing a weak acid treatment step in Example 4. The weak acid treatment removes metal salts and low-molecular-weight byproducts that may remain at the pore inlets and particle surfaces, and improves the wettability of the material surface to the electrolyte, thus reducing the migration resistance of ions at the pore inlets and interface regions. Therefore, the material of Example 4 treated with the weak acid exhibits lower ion diffusion resistance and better rate performance.

[0101] Furthermore, the weak acid treatment helps alleviate local interfacial stress generated during confined in-situ polymerization, resulting in a more uniform distribution of the PEDOT conductive network in the pores and surface areas, thereby suppressing localized shedding of the conductive phase during long-term cycling. Compared to the untreated sample, Example 4, treated with weak acid, maintained a higher capacity retention rate after 10,000 charge-discharge cycles, indicating better long-term stability of its interfacial structure and conductive network.

[0102] It should be noted that the above-mentioned performance improvement comes from the mild regulation of the pore inlet and interface state by the weak acid treatment, and does not cause substantial dissolution of the ZIF-8 porous framework or change in pore size.

[0103] In summary, the PEDOT conductive primer and the hybrid process of "wet primer + dry active layer" provided by this invention effectively solve the interface problem of dry electrodes. This primer not only serves as a physical bonding layer but also as a functional conductive layer and capacitance-contributing layer, significantly improving the overall electrochemical performance of supercapacitors and demonstrating feasibility for industrial production.

[0104] These data fully demonstrate that confined in-situ polymerization + porous skeleton construction of a dual continuous network + interfacial chemical bonding between PEDOT and the skeleton is the key mechanism for achieving synergistic electron / ion conduction, reducing interfacial impedance, and enhancing rate performance and cycle stability. The simple physical mixing method used in the comparative example cannot achieve the same effect.

[0105] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0106] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0107] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0108] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrically conductive primer material, characterized in that, The conductive primer material comprises porous material and poly-3,4-ethylenedioxythiophene layer formed by confined in-situ oxidative polymerization of 3,4-ethylenedioxythiophene, the poly-3,4-ethylenedioxythiophene layer is attached to the pores and / or surface of the porous material, the poly-3,4-ethylenedioxythiophene layer and the porous material are connected by strong interaction, the porous material is ion conductive phase, and the poly-3,4-ethylenedioxythiophene layer is electronic conductive phase.

2. The conductive primer material of claim 1, wherein The porous material is selected from at least one of mesoporous silica, MOF and COF; The pore size of the porous material is 0.3 nm to 5 nm.

3. The conductive primer material of claim 2, wherein The MOF is selected from at least one of MIL-100 (Fe), ZIF-8, UiO-66 and HKUST-1; The COF is selected from at least one of TpPa-SO3H, TpPa-NH2, COF-300 and COF-316.

4. The conductive primer material according to any one of claims 1 to 3, characterized in that, The mass ratio of the poly-3,4-ethylenedioxythiophene layer and the porous material is 1 to 8:2 to 9.

5. The conductive primer material of claim 4, wherein The pores of the porous material have at least one of -SO3H, -SO 3- , -NH2 and -COOH on the inside and / or on the surface. The strong interaction is selected from at least one of electrostatic interaction, hydrogen bond interaction, π-π stacking interaction and metal coordination interaction.

6. A method for producing the conductive primer material according to any one of claims 1 to 5, characterized by, The method comprises the following steps: The porous material and 3,4-ethylenedioxythiophene are uniformly mixed in a dispersant, so that the 3,4-ethylenedioxythiophene enters the pores of the porous material or is adsorbed on the surface of the porous material, and a dispersion liquid is obtained; An oxidizing agent is added to the dispersion liquid, so that the 3,4-ethylenedioxythiophene is subjected to confined in-situ oxidative polymerization, thereby forming a poly-3,4-ethylenedioxythiophene layer attached to the pores and / or surface of the porous material, and a conductive primer material required is obtained after separation.

7. The method of claim 6, wherein the conductive primer material is prepared by mixing the conductive primer material of claim 6 with a solvent. In the operation of uniformly mixing the porous material and 3,4-ethylenedioxythiophene in a dispersant, the mass ratio of the porous material and 3,4-ethylenedioxythiophene is 1:0.1 to 5, and the dispersant is water or a mixed solution of water and ethanol with a volume ratio of 1 to 9:1; In the operation of adding an oxidizing agent to the dispersion liquid so that the 3,4-ethylenedioxythiophene is subjected to confined in-situ oxidative polymerization, the oxidizing agent is selected from at least one of FeCl3, APS, H2O2 and Cu(ClO4)2, the reaction temperature is 0 to 50°C, and the reaction time is 0.5 h to 12 h.

8. The method of claim 6, wherein the conductive primer material is prepared by mixing the conductive primer material of claim 6 with a solvent. The method for preparing the conductive primer material further comprises, after the operation of obtaining the conductive primer material required after separation, the following operation: soaking the conductive primer material in a weak acid solution to regulate the pore entrance and surface state of the porous material, reduce the pore bending degree and improve the pore connectivity, the concentration of the weak acid solution is 0.01 mol / L to 0.5 mol / L, and the solute of the weak acid solution is selected from at least one of acetic acid and citric acid.

9. A current collector characterized by comprising: The conductive primer material comprises porous material and poly-3,4-ethylenedioxythiophene layer formed by confined in-situ oxidative polymerization of 3,4-ethylenedioxythiophene, the poly-3,4-ethylenedioxythiophene layer is attached to the pores and / or surface of the porous material, the poly-3,4-ethylenedioxythiophene layer and the porous material are connected by strong interaction, the porous material is ion conductive phase, and the poly-3,4-ethylenedioxythiophene layer is electronic conductive phase.

10. An energy storage device, characterized by, The current collector comprises the conductive primer material.

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