Conductive carbon black composite material for lithium ion battery and preparation method thereof

Abstract

The application discloses a conductive carbon black composite material for lithium ion batteries and a preparation method thereof, and belongs to the technical field of carbon black materials. First, the conductive carbon black composite material comprises the following raw materials in mass parts: 100g of conductive carbon black, 5.4-6.5 parts of dopamine hydrochloride, 200-300 parts of a PEDOT:PSS dispersion liquid, 8.0-10.0 parts of nickel powder, 2.0-2.5 parts of tris-hydroxymethyl aminomethane, 1.0-2.0 parts of CaCl2 and 2000 parts of deionized water. The application realizes breakthroughs in the dimensions of high rate (5C capacity retention rate 89.3%), long cycle (500 times retention rate 93.8%) and low expansion (8.7%) through a triple synergistic mechanism of PDA / PEDOT:PSS double-component coating, nickel powder embedding and Ca 2+ cross-linking stable structure.

Description

Technical Field

[0001] This invention belongs to the field of carbon black material technology, specifically relating to a conductive carbon black composite material for lithium-ion batteries and its preparation method. Background Technology

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their high energy density, long cycle life, and low self-discharge rate. In the positive and negative electrode materials of lithium-ion batteries, a certain proportion of conductive agents is usually added to improve electron conductivity. Carbon black is one of the most widely used conductive agents because its large specific surface area, high conductivity, and good dispersibility can significantly improve the electron conduction network between the electrode current collector and the active material. However, carbon black alone cannot simultaneously achieve both ion transport efficiency and conductive network stability under high-rate charge and discharge conditions, thus limiting the performance improvement of lithium-ion batteries in high-power output and long-life applications.

[0003] In existing technologies, methods such as surface modification, composite carbon nanotubes, and graphene have been used to improve the dispersibility and conductive network stability of carbon black in electrode formulations. However, in mass production, these methods often suffer from problems such as complex processes, high costs, unstable dispersibility, and poor binder compatibility. Especially in wet coating and large-size electrode fabrication processes, traditional carbon black modification schemes are prone to conductive agent agglomeration and uneven electrode pore structure, leading to increased internal resistance and accelerated capacity decay.

[0004] With the increasing demands for high power density and high cycle stability in power batteries and energy storage systems, conductive agents not only need to possess high conductivity but also need to maintain stable dispersion and structural integrity during complex processing and long-term charge-discharge cycles. Therefore, there is an urgent need to develop a conductive carbon black composite material with a simple preparation method, controllable cost, suitability for mass production, and the ability to significantly improve the structural stability and electrochemical performance of carbon black in electrodes. This is of great significance for promoting the application of lithium-ion batteries in high-power and long-life applications. Summary of the Invention

[0005] The purpose of this invention is to provide a conductive carbon black composite material for lithium-ion batteries and its preparation method. By improving the conductive carbon black and sulfonated polymer raw materials, the synergistic effect of the two is enhanced, solving the problems in the prior art, and further improving electrolyte wettability and volume expansion, thereby achieving high rate performance and long cycle life. The purpose of this invention can be achieved through the following technical solutions:

[0006] A conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0007] Conductive carbon black: 100 parts;

[0008] Dopamine hydrochloride: 5.4–6.5 parts;

[0009] PEDOT:PSS dispersion: 200-300 parts;

[0010] Nickel powder: 8.0–10.0 parts;

[0011] Tris(hydroxymethyl)aminomethane: 2.0–2.5 parts;

[0012] CaCl2: 1.0–2.0 parts;

[0013] Deionized water: 2000 portions.

[0014] Furthermore, the conductive carbon black is of the type Ketjenblack EC-600JD; and the dopamine hydrochloride is of the type Dopamine·HCl.

[0015] Furthermore, the solid content of the PEDOT:PSS dispersion is 1.3% to 1.7%.

[0016] Furthermore, the nickel powder is spherical; the particle size of the nickel powder is 0.5 μm.

[0017] Furthermore, the preparation method of the conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0018] S1. Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black in deionized water and ultrasonically stir for 5-10 min at room temperature to form a uniform suspension. Then add tris(hydroxymethyl)aminomethane to the uniform suspension and continue ultrasonic stirring for 3-5 min. Then add dopamine hydrochloride and PEDOT:PSS dispersion to it and mechanically stir for 12 h at room temperature. After completion, a carbon black coated suspension is obtained.

[0019] S2. Add nickel powder to the coated carbon black suspension of S1, continue mechanical stirring for 3-5 h, then add CaCl2 and let stand for 3 h to obtain the crosslinked product;

[0020] S3. Separate the crosslinking product using a filter membrane, collect the solid component and dry it in a vacuum drying oven at 55-60℃ for 24 h. After completion, a conductive carbon black composite material for lithium-ion batteries is obtained.

[0021] Furthermore, the pore size of the filter membrane is 0.1 μm.

[0022] The beneficial effects of this invention are:

[0023] This invention provides a conductive carbon black composite material for lithium-ion batteries and its preparation method. The technical solution of this invention achieves performance breakthroughs in high-rate (89.3% capacity retention at 5C), long-cycle (93.8% retention after 500 cycles), and low expansion (8.7%) dimensions of the conductive carbon black composite material for lithium-ion batteries. The data analysis is as follows:

[0024] (1) Improved performance at high magnification:

[0025] Example 2's 5C capacity retention rate (89.3%) far exceeds that of Comparative Example 1 (78.4%) and traditional carbon black (industry average <80%), solving the problem of rapid capacity drop under high power output.

[0026] (2) Significantly extended cycle life:

[0027] Example 2 showed a capacity retention of 93.8% after 500 cycles, which is nearly 10% higher than Comparative Example 4 (84.6%), and a 53% reduction in electrode expansion rate (8.7% vs 18.3%).

[0028] (3) Interface dynamics optimization:

[0029] Rct decreased to 15.3 Ω (compared to 42.3 Ω in Comparative Example 2), and the electrolyte contact angle reached 26.4° (approaching superhydrophilicity), accelerating the electrode reaction.

[0030] (4) Strong process compatibility:

[0031] The room-temperature aqueous phase process (S1-S3) avoids high temperatures and organic solvents, making it suitable for large-scale production and overcoming the cost and dispersion challenges of nanotube / graphene composites in existing technologies.

[0032] In summary, this invention utilizes a triple synergistic mechanism: PDA / PEDOT:PSS dual-component coating (improving wettability and dual conductivity), nickel powder embedding to enhance the electronic network, and Ca... 2+ The cross-linked stable structure enables breakthroughs in conductive agents in terms of high rate (89.3% capacity retention at 5C), long cycle life (93.8% retention after 500 cycles), and low expansion (8.7%), providing a reliable solution for high power and long life of lithium-ion batteries. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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. Furthermore, unless otherwise specified, the raw materials, reagents, or devices used in the following embodiments can be obtained from conventional commercial channels or by existing known methods.

[0034] Example 1

[0035] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0036] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0037] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0038] Dopamine hydrochloride (Dopamine·HCl, analytical grade): 5.4 g;

[0039] PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%): 200 g;

[0040] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.0g;

[0041] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.0 g;

[0042] CaCl2 (analytical grade): 1.0g;

[0043] Deionized water: 2000g.

[0044] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0045] S1. Formation of the coating layer:

[0046] Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (300 W) for 5 min at room temperature to form a uniform suspension. Then, add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 3 min. Subsequently, add dopamine hydrochloride and PEDOT:PSS dispersion to the suspension and mechanically stir (200 rpm) for 12 h at room temperature. After completion, a coated carbon black suspension is obtained. In this suspension, dopamine self-polymerizes into polydopamine (PDA) and co-deposits with PEDOT:PSS on the carbon black surface to form a flexible coating layer, which improves ion transport and electrolyte wettability. Finally, a coated carbon black suspension is obtained.

[0047] S2, Metal microparticle implantation and ion crosslinking:

[0048] Nickel powder was added to the S1 coated carbon black suspension, and mechanical stirring was continued (200 rpm) for 3 h. The nickel powder embedded itself in the pores of the coating layer, enhancing electron conduction. Subsequently, CaCl2 was added, and the mixture was allowed to stand for 3 h to obtain the crosslinked product. 2+ Ionic crosslinking with sulfonic acid groups in PEDOT:PSS enhances network stability and buffers volume expansion, yielding a crosslinked product.

[0049] S3. Solid-liquid separation and drying:

[0050] The crosslinking products were separated using a vacuum filtration device (filter membrane pore size 0.1 μm), and the solid components were collected and dried in a vacuum drying oven at 55 °C for 24 h. After drying, a conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0051] Example 2

[0052] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0053] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0054] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0055] Dopamine hydrochloride (Dopamine·HCl, analytical grade): 6.2 g;

[0056] PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%): 250 g;

[0057] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.4g;

[0058] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.2 g;

[0059] CaCl2 (analytical grade): 1.2g;

[0060] Deionized water: 2000g.

[0061] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0062] S1. Formation of the coating layer:

[0063] Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (300 W) at room temperature for 10 min to form a uniform suspension. Then, add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Subsequently, add dopamine hydrochloride and PEDOT:PSS dispersion to the suspension and mechanically stir (200 rpm) at room temperature for 12 h. After completion, a coated carbon black suspension is obtained. In this suspension, dopamine self-polymerizes into polydopamine (PDA) and co-deposits with PEDOT:PSS on the carbon black surface to form a flexible coating layer, which improves ion transport and electrolyte wettability. Finally, a coated carbon black suspension is obtained.

[0064] S2, Metal microparticle implantation and ion crosslinking:

[0065] Nickel powder was added to the S1 coated carbon black suspension, and mechanical stirring was continued (200 rpm) for 5 h. The nickel powder embedded itself in the pores of the coating layer, enhancing electron conduction. Subsequently, CaCl2 was added, and the mixture was allowed to stand for 3 h to obtain the crosslinked product. 2+ Ionic crosslinking with sulfonic acid groups in PEDOT:PSS enhances network stability and buffers volume expansion, yielding a crosslinked product.

[0066] S3. Solid-liquid separation and drying:

[0067] The crosslinking products were separated using a vacuum filtration device (filter membrane pore size 0.1 μm), and the solid components were collected and dried in a vacuum drying oven at 60 °C for 24 h. After drying, a conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0068] Example 3

[0069] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0070] Example 3 is a control group of Example 2. The amount of PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%) in Example 2 was adjusted to 200 g, while the other raw materials, raw material amounts and preparation steps remained the same as in Example 2. Finally, conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0071] Example 4

[0072] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0073] Example 4 is a control group of Example 2. The amount of PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%) in Example 2 was adjusted to 300 g, while the remaining raw materials, raw material amounts and preparation steps remained the same as in Example 2. Finally, conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0074] Example 5

[0075] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0076] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0077] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0078] Dopamine hydrochloride (Dopamine·HCl, analytical grade): 6.5g;

[0079] PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%): 300 g;

[0080] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 10.0g;

[0081] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.5g;

[0082] CaCl2 (analytical grade): 2.0g;

[0083] Deionized water: 2000g.

[0084] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0085] S1. Formation of the coating layer:

[0086] Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (300 W) at room temperature for 10 min to form a uniform suspension. Then, add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Subsequently, add dopamine hydrochloride and PEDOT:PSS dispersion to the suspension and mechanically stir (200 rpm) at room temperature for 12 h. After completion, a coated carbon black suspension is obtained. In this suspension, dopamine self-polymerizes into polydopamine (PDA) and co-deposits with PEDOT:PSS on the carbon black surface to form a flexible coating layer, which improves ion transport and electrolyte wettability. Finally, a coated carbon black suspension is obtained.

[0087] S2, Metal microparticle implantation and ion crosslinking:

[0088] Nickel powder was added to the S1 coated carbon black suspension, and mechanical stirring was continued (200 rpm) for 5 h. The nickel powder embedded itself in the pores of the coating layer, enhancing electron conduction. Subsequently, CaCl2 was added, and the mixture was allowed to stand for 3 h to obtain the crosslinked product. 2+ Ionic crosslinking with sulfonic acid groups in PEDOT:PSS enhances network stability and buffers volume expansion, yielding a crosslinked product.

[0089] S3. Solid-liquid separation and drying:

[0090] The crosslinking products were separated using a vacuum filtration device (filter membrane pore size 0.1 μm), and the solid components were collected and dried in a vacuum drying oven at 60 °C for 24 h. After drying, a conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0091] Comparative Example 1

[0092] Comparative Example 1 served as the control group for Example 2. The dopamine hydrochloride raw material from Example 2 was removed, while the remaining raw materials, amounts, and preparation steps remained consistent with Example 2, ultimately yielding a conductive carbon black composite material (black powder) for lithium-ion batteries. Details are as follows:

[0093] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0094] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0095] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0096] PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%): 250 g;

[0097] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.4g;

[0098] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.2 g;

[0099] CaCl2 (analytical grade): 1.2g;

[0100] Deionized water: 2000g.

[0101] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0102] S1. Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (power 300 W) for 10 min at room temperature to form a uniform suspension. Then add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Then add PEDOT:PSS dispersion to it and mechanically stir (speed 200 rpm) for 12 h at room temperature. After completion, a carbon black coated suspension is obtained.

[0103] S2. Add nickel powder to the coated carbon black suspension from S1 and continue mechanical stirring (200 rpm) for 5 hours. The nickel powder embeds into the pores of the coating layer, enhancing electron conduction. Then, add CaCl2 and let stand for 3 hours to obtain the crosslinked product. 2+ Ionic crosslinking occurs with the sulfonic acid groups in PEDOT:PSS to obtain the crosslinked product;

[0104] S3. The crosslinking product was separated using a vacuum filtration device (filter membrane pore size 0.1μm), and the solid component was collected and dried in a vacuum drying oven at 60℃ for 24 h. After completion, a conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0105] Comparative Example 2

[0106] Comparative Example 2 served as the control group for Example 2. The raw material "PEDOT:PSS dispersion" from Example 2 was removed, while the remaining raw materials, amounts, and preparation steps remained consistent with Example 2, ultimately yielding a conductive carbon black composite material (black powder) for lithium-ion batteries. Details are as follows:

[0107] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0108] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0109] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0110] Dopamine hydrochloride (Dopamine·HCl, analytical grade): 6.2 g;

[0111] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.4g;

[0112] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.2 g;

[0113] CaCl2 (analytical grade): 1.2g;

[0114] Deionized water: 2000g.

[0115] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0116] S1. Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (power 300 W) for 10 min at room temperature to form a uniform suspension. Then add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Then add dopamine hydrochloride and mechanically stir (speed 200 rpm) for 12 h at room temperature. After completion, a carbon black coated suspension is obtained.

[0117] S2. Add nickel powder to the coated carbon black suspension in S1 and continue mechanical stirring (200 rpm) for 5 h. The nickel powder is embedded in the pores of the coating layer, which enhances electron conduction. Then, add CaCl2 and let stand for 3 h to obtain the product.

[0118] S3. Separate the product using a vacuum filtration device (filter membrane pore size 0.1μm), collect the solid components and dry them in a vacuum drying oven at 60℃ for 24 h. After completion, a conductive carbon black composite material (black powder) for lithium-ion batteries is obtained.

[0119] Comparative Example 3

[0120] Comparative Example 3 served as the control group for Example 2. The raw materials "dopamine hydrochloride and PEDOT:PSS dispersion" from Example 2 were removed, while the remaining raw materials, amounts, and preparation steps remained consistent with Example 2, ultimately yielding a conductive carbon black composite material (black powder) for lithium-ion batteries. Details are as follows:

[0121] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0122] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0123] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0124] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.4g;

[0125] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.2 g;

[0126] CaCl2 (analytical grade): 1.2g;

[0127] Deionized water: 2000g.

[0128] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0129] S1. Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (power 300 W) for 10 min at room temperature to form a uniform suspension. Then add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Then mechanically stir (speed 200 rpm) at room temperature for 12 h. After completion, a carbon black suspension is obtained.

[0130] S2. Add nickel powder to the carbon black suspension in S1 and continue mechanical stirring (200 rpm) for 5 h. The nickel powder is embedded in the pores of the coating layer to enhance electron conduction. Then, CaCl2 is added and the mixture is allowed to stand for 3 h to obtain the product.

[0131] S3. Separate the product using a vacuum filtration device (filter membrane pore size 0.1μm), collect the solid components and dry them in a vacuum drying oven at 60℃ for 24 h. After completion, a conductive carbon black composite material (black powder) for lithium-ion batteries is obtained.

[0132] Comparative Example 4

[0133] Comparative Example 4 served as the control group for Example 2. The raw material "CaCl2" was removed from Example 2, meaning there was no ionic crosslinking process. The remaining raw materials, amounts, and preparation steps remained consistent with Example 2, ultimately yielding a conductive carbon black composite material (black powder) for lithium-ion batteries. Details are as follows:

[0134] Preparation of conductive carbon black composite materials for lithium-ion batteries:

[0135] First, the conductive carbon black composite material for lithium-ion batteries comprises the following raw materials in parts by weight:

[0136] Conductive carbon black (Ketjenblack EC-600JD, specific surface area ≥1270 m²) 2 / g, DBP oil absorption value ≥400 mL / 100g): 100g;

[0137] Dopamine hydrochloride (Dopamine·HCl, analytical grade): 6.2 g;

[0138] PEDOT:PSS dispersion (Clevios PH1000, solid content 1.3%~1.7%): 250 g;

[0139] Nickel powder (spherical, particle size 0.5μm, metal purity ≥99%): 8.4g;

[0140] Tris(hydroxymethyl)aminomethane (Tris, analytical grade): 2.2 g;

[0141] Deionized water: 2000g.

[0142] Then, the preparation method of conductive carbon black composite material for lithium-ion batteries includes the following steps:

[0143] S1. Formation of the coating layer:

[0144] Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black (Ketjenblack EC-600JD) in deionized water and ultrasonically stir (300 W) at room temperature for 10 min to form a uniform suspension. Then, add tris(hydroxymethyl)aminomethane (Tris) to the uniform suspension and continue ultrasonic stirring for 5 min. Subsequently, add dopamine hydrochloride and PEDOT:PSS dispersion to the suspension and mechanically stir (200 rpm) at room temperature for 12 h. After completion, a coated carbon black suspension is obtained. In this suspension, dopamine self-polymerizes into polydopamine (PDA) and co-deposits with PEDOT:PSS on the carbon black surface to form a flexible coating layer, which improves ion transport and electrolyte wettability. Finally, a coated carbon black suspension is obtained.

[0145] S2. Solid-liquid separation and drying:

[0146] The carbon black suspension was separated by a vacuum filtration device (filter membrane pore size 0.1 μm), and the solid components were collected and dried in a vacuum drying oven at 60 °C for 24 h. After drying, a conductive carbon black composite material (black powder) for lithium-ion batteries was obtained.

[0147] The conductive carbon black composite materials for lithium-ion batteries prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to performance testing. The performance testing process is as follows, and the test results are shown in Table 1 (data are the average of 10 parallel experiments):

[0148] (1) Electrode preparation:

[0149] Formulation: 90 wt% positive electrode active material LiFePO4 (LFP), 5 wt% conductive agent (conductive carbon black composite material for lithium-ion batteries prepared in the examples or comparative examples), and 5 wt% binder PVDF.

[0150] Process: The raw materials were mixed in NMP solvent, ball-milled for 2 h (500 rpm), coated on aluminum foil (15 μm thick), dried at 110℃ for 12 h, rolled to a porosity of 30%, and cut into 12 mm diameter electrode sheets.

[0151] (2) Battery assembly:

[0152] The CR2032 coin cell is used: the positive electrode is the above-mentioned electrode, the negative electrode is a lithium sheet, the electrolyte is 1M LiPF6 in EC / DMC (1:1 v / v), and the separator is Celgard 2400.

[0153] All batteries were assembled at 25°C and humidity <10%.

[0154] (3) Test methods and results:

[0155] A. Volumetric conductivity test: Using a four-probe resistance meter (model RTS-9, Zhuhai Omec), the conductive agent powder was compressed into a tablet (pressure 10 MPa), and the conductivity (unit: S / cm) was tested.

[0156] B. Rate Performance Test: The battery is charged at a constant current of 0.2C to 3.65V, then at a constant voltage until the current is <0.05C; it is discharged from 0.5C to 5C rate, and the discharge specific capacity (unit: mAh / g) is recorded. Capacity retention rate = (5C capacity / 0.5C capacity) × 100%.

[0157] C. Cycle life test: The battery is charged and discharged at a 1C rate (voltage range 2.5-3.65V) for 500 cycles, and the capacity retention rate is recorded (unit: %).

[0158] D. AC impedance test: Using an electrochemical workstation (model CHI760E), with a frequency range of 0.1 Hz-100 kHz and an amplitude of 10 mV, the charge transfer internal resistance (Rct, unit: Ω) was recorded.

[0159] E. Electrolyte contact angle test: Place the electrode plate under a drop of electrolyte (volume 2 μL) and record the static contact angle (unit: °) using a contact angle meter (model JC2000D).

[0160] F. Electrode expansion rate test: After 100 cycles, measure the electrode thickness change rate (expansion rate = [(thickness after cycles - initial thickness) / initial thickness] × 100%).

[0161] Table 1 Test Results

[0162]

[0163] Analysis of the data in Table 1:

[0164] (a) The mechanism of action of synergistic component design:

[0165] The triple synergistic effect is verified by comparing the examples and comparative examples (data in Table 1):

[0166] 1. PDA / PEDOT: PSS flexible coating layer (improves ion / electron conduction)

[0167] (1) Principle: Dopamine self-polymerizes to form polydopamine (PDA), which synergistically coats the carbon black surface with PEDOT:PSS:

[0168] PDA enhances interfacial bonding and promotes ion transport;

[0169] PEDOT:PSS fills the pores of carbon black, creating an efficient electronic pathway (the hydrophilic sulfonic acid groups improve wettability).

[0170] (2) Data validation:

[0171] Example 2 (with two components): volume conductivity 37.8 S / cm, contact angle 26.4°, Rct only 15.3Ω.

[0172] Comparative Example 1 (without PDA): conductivity decreased to 32.6 S / cm, contact angle increased to 45.7°, and Rct reached 28.6Ω (ion transport was blocked).

[0173] Comparative Example 2 (without PEDOT:PSS): The conductivity plummeted to 26.3 S / cm, the contact angle was 58.2°, and the Rct was as high as 42.3Ω (deterioration of electronic conduction).

[0174] 2. Electron networks reinforced with nickel powder

[0175] (1) Principle: Nickel powder is embedded in the pores of the coating layer, providing an additional electron conduction path.

[0176] (2) Data validation:

[0177] Comparative Example 3 (without PDA / PEDOT:PSS, only nickel powder): conductivity 28.9 S / cm, much lower than Example 2 (37.8 S / cm), proving that the effect of adding a single metal is limited.

[0178] 3.Ca 2+ Ionic crosslinking enhances structural stability

[0179] (1) Principle: Ca 2+ Crosslinking with the sulfonic acid groups of PEDOT:PSS forms a stable network that buffers volume changes during charge and discharge.

[0180] (2) Data validation:

[0181] Example 2: After 500 cycles, the capacity retention rate was 93.8%, and the expansion rate was only 8.7%.

[0182] Comparative Example 4 (without Ca) 2+ Crosslinking: The retention rate dropped to 84.6%, and the expansion rate rose to 18.3% (insufficient network stability).

[0183] (II) Performance balance of optimized formulation:

[0184] Examples 2-4 show the adjustment of PEDOT:PSS dosage (200g → 250g → 300g), with peak performance observed.

[0185] 1. Optimal ratio (Example 2: 250g): conductivity 37.8 S / cm, 5C retention rate 89.3%, with the best overall performance.

[0186] 2. Effects of excessive amount (Examples 4-5): When PEDOT:PSS is increased to 300g, the conductivity and rate performance decrease slightly (excessive coating may hinder conduction).

[0187] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0188] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A conductive carbon black composite material for lithium-ion batteries, characterized in that, Includes the following quantities of raw materials: Conductive carbon black: 100 parts; Dopamine hydrochloride: 5.4–6.5 parts; PEDOT:PSS dispersion: 200-300 parts; Nickel powder: 8.0–10.0 parts; Tris(hydroxymethyl)aminomethane: 2.0–2.5 parts; CaCl2: 1.0–2.0 parts; Deionized water: 2000 portions.

2. The conductive carbon black composite material for lithium-ion batteries according to claim 1, characterized in that, The conductive carbon black is of the type Ketjenblack EC-600JD; the dopamine hydrochloride is of the type Dopamine·HCl.

3. The conductive carbon black composite material for lithium-ion batteries according to claim 1, characterized in that, The solid content of the PEDOT:PSS dispersion is 1.3% to 1.7%.

4. The conductive carbon black composite material for lithium-ion batteries according to claim 1, characterized in that, The nickel powder is spherical; the particle size of the nickel powder is 0.5 μm.

5. A method for preparing a conductive carbon black composite material for lithium-ion batteries according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Weigh the above raw materials according to the mass fraction. First, disperse the conductive carbon black in deionized water and ultrasonically stir for 5-10 min at room temperature to form a uniform suspension. Then add tris(hydroxymethyl)aminomethane to the uniform suspension and continue ultrasonic stirring for 3-5 min. Then add dopamine hydrochloride and PEDOT:PSS dispersion to it and mechanically stir for 12 h at room temperature. After completion, a carbon black coated suspension is obtained. S2. Add nickel powder to the coated carbon black suspension of S1, continue mechanical stirring for 3-5 h, then add CaCl2 and let stand for 3 h to obtain the crosslinked product; S3. Separate the crosslinking product using a filter membrane, collect the solid component and dry it in a vacuum drying oven at 55-60℃ for 24 h. After completion, a conductive carbon black composite material for lithium-ion batteries is obtained.

6. The method for preparing a conductive carbon black composite material for lithium-ion batteries according to claim 5, characterized in that, The filter membrane described in S3 has a pore size of 0.1 μm.

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