A lithium supplement-containing porous composite material, a preparation method and application thereof

Abstract

The application discloses a kind of containing lithium supplement agent's porous composite material, which is composed of porous structure carbon material, lithium supplement agent, enhanced conductive material, can contain or not contain other element coating layer etc..Among them, the porous structure carbon material is used as carbon skeleton and support structure for adsorbing lithium supplement agent and storing electrolyte;Lithium supplement agent is used to improve battery cycle performance;Enhanced conductive material is used to further improve the electronic conductivity of the material and improve the kinetics, reduce the powder resistance of the material, solve the defect that the electronic conductivity of the porous carbon material itself is not high;Coating layer with or without surface coating is better for the enhanced conductive material to coat on the surface of the porous material to reduce the resistance of the material.

Description

Technical Field

[0001] This invention relates to the field of porous composite material containing lithium replenishing agent for lithium-ion batteries, and particularly to a porous composite material containing lithium replenishing agent, its preparation method and application. Background Technology

[0002] As the application of lithium-ion batteries continues to expand, especially in the fields of new energy vehicles and energy storage, people are placing increasingly higher demands on battery performance, such as energy density and cycle life. With the research and application of new high-capacity anode materials such as silicon-based anodes, the lithium loss problem during battery charging and discharging is becoming increasingly prominent, giving rise to lithium replenishment technology.

[0003] Among existing related technologies, for example, the article "External Li supply reshapes Li-deficiency and lifetime limit of batteries" utilizes the functional organic molecule lithium trifluoromethyl sulfinate (CF3SO2Li) dissolved in a conventional electrolyte to replenish lithium ions in batteries, and determines that it has optimal electrochemical activity, potential, product formation, electrolyte solubility, and specific capacity. The results show that when added externally to an assembled battery, the lithium salt undergoes oxidative decomposition during battery charging, releasing active Li+, and the negatively charged (SO2CF3)- organic groups lose electrons, transforming into SO2 and C2F6 gases, which are then discharged as gases. This non-invasive and rapid process maintains the integrity of the battery without requiring disassembly. This technical solution is similar to organic lithium replenishers, but the lithium replenishment process also generates gas.

[0004] Furthermore, the article "Nitrogen-Centered Organic Salts Enable Stable Lithium-IonSupply for High-Energy-Density Batteries" discloses the use of Li₂N₂C₇H₄O. This molecule, within a typical operating voltage window of 3.8–4.3V, undergoes a two-step radical oxidation reaction to release lithium ions, simultaneously generating benzimidazolone (N₂C₇H₄O) as a byproduct. Unlike traditional carbon-centered lithium salts, Li₂N₂C₇H₄O does not release gas during decomposition, and its byproducts can complex with Ni, Co, and Mn ions, stabilizing the high-nickel cathode interface and suppressing transition metal dissolution and side reactions. However, in this article, Li₂N₂C₇H₄O is insoluble in the electrolyte system. Instead, it is mixed with the cathode, conductive agent, and adhesive in the electrode, and decomposes to release lithium ions after charging to a certain voltage, thus achieving lithium replenishment.

[0005] In existing related technologies, the aforementioned lithium replenishment materials need to be decomposed under high pressure. If dissolved in the electrolyte system, the lithium replenishment agent on the negative electrode side is difficult to decompose and will remain in the electrolyte system, resulting in severe gas generation during long cycles. In addition, organic lithium salt lithium replenishment agents have poor electronic conductivity.

[0006] This solution proposes a porous composite material containing a lithium replenisher, a product not yet available. The material comprises a porous carbon material, a lithium replenisher, a reinforcing conductive material (which may or may not contain other elements), and a coating layer. The porous carbon material serves as a carbon skeleton and supporting structure for adsorbing the lithium replenisher and storing the electrolyte. The lithium replenisher improves battery cycle performance. The reinforcing conductive material further enhances the material's electronic conductivity and kinetics, reduces powder resistance, and addresses the inherent poor electronic conductivity of the porous carbon material. The coating layer (which may or may not contain surface coatings) allows the reinforcing conductive material to adhere better to the surface of the porous material, reducing its resistance. Summary of the Invention

[0007] The purpose of this invention is to provide a material composed of a porous carbon material, a lithium replenisher, a coating layer that may or may not contain other elements. The porous carbon material serves as a carbon skeleton and supporting structure for adsorbing the lithium replenisher and storing the electrolyte; the lithium replenisher improves battery cycle performance; the reinforced conductive material further enhances the material's electronic conductivity, improves kinetics, and reduces the material's powder resistance; the coating layer, which may or may not contain a surface coating, allows the reinforced conductive material to better coat the surface of the porous material, further reducing the material's resistance.

[0008] A porous composite material containing a lithium replenishing agent can effectively address the poor electronic conductivity of organic lithium salt lithium replenishing agents, thus solving the problem of severe gas generation during long-term cycling caused by the aforementioned lithium replenishing materials remaining in the electrolyte system.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a porous composite material for use with a lithium supplementing agent, the material comprising a porous carbon material a, a lithium supplementing agent b, a reinforcing conductive material c (which may or may not contain reinforcing conductive material), and a coating layer d (which may or may not contain other elements); wherein a+b+c+d=100%, 10%≤a<100%, 0%<b≤90%, 0%≤c≤5%, 0%≤d≤5%; the most significant characteristic of this material is that even after coating with the lithium supplementing agent and conductive slurry, it still possesses a certain porosity and specific surface area. The specific surface area and porosity after coating are slightly lower than those of the raw porous carbon or activated carbon (porosity ≥10%, 100g / m³). 3 ≤Specific surface area≤2900 g / m 3 ).

[0011] As a specific technical solution, the porous carbon material content of the composite material can be 10% ≤ a < 100%, specifically 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80, 90, 100 parts, or any numerical proportion thereof; the lithium replenishing agent content can be 0 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, or any numerical proportion thereof; the content of the reinforcing conductive agent can be 5 parts, 4 parts, 3 parts, 2 parts, 1 part, or any numerical proportion thereof; the mass content of the coating layer, which may or may not contain other elements, is c, 0 ≤ c ≤ 5%, specifically 1 part, 4 parts, 3 parts, 2 parts, 5 parts, or any numerical proportion thereof; other coating elements can be 0 parts, 1 part, 4 parts, 3 parts, 2 parts, 5 parts, or any numerical proportion thereof.

[0012] Furthermore, if the other coating element is carbon, the carbon coating content is 0 ≤ d ≤ 5%; it can be 0%, 1%, 2%, 3%, 4%, 5%, or any of these percentages. The carbon content is preferably 0 ≤ d ≤ 5%. The thickness of the 0 ≤ carbon coating is set to ≤ 200 nm, more preferably ≤ 100 nm; and even more preferably ≤ 50 nm.

[0013] As a specific technical solution, the composite material has a specific surface area and porosity (porosity ≥10%, 100g / m³). 3 ≤Specific surface area≤2900 g / m 3 The porosity is 10% ≤ porosity ≤ 90%; specifically, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any of these percentages. Higher porosity results in a larger specific surface area, but reduces the initial efficiency of the battery. Additionally, porous materials have lower mechanical strength. Specific surface area ≥ 100 g / m² 3 ≤Specific surface area≤2900 g / m 3 Specifically, these can be 100, 200, 500, 1000, 2000, 2500, or 2900 g / m³. 3 It can be any of these values; the higher the specific surface area, the lower the initial efficiency of the battery.

[0014] Secondly, the present invention provides a method for preparing the above-mentioned composite material, comprising the following steps:

[0015] S1. The synthesis of the lithium supplement in claim 3 above, and its dissolution in a solvent to prepare a homogeneous solution of a certain concentration;

[0016] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0017] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material and the loading of the lithium supplement is controlled. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0018] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing a conductive agent, and then dried;

[0019] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0020] As a specific technical solution, in step S1, the synthesis of the lithium replenishing agent is as follows: For example, if the lithium replenishing agent is lithium trifluoromethanesulfonyl trioxide (LiSO2CF3), it is prepared by reacting sodium trifluoromethanesulfonate with lithium hydroxide added in an ice bath; if the lithium replenishing agent is lithium benzimidazole-2-one (Li2N2C7H4O), it is prepared by reacting 2H-benzimidazole-2-one (C7H6N2O) with lithium methoxide (CH3OLi); if the lithium replenishing agent is lithium squaric acid, it is prepared by reacting squaric acid with lithium carbonate; if the lithium replenishing agent is Li3C6H3S3, it is prepared by reacting trithiocyanate and lithium salt as lithium hydroxide; if the lithium replenishing agent is Li3C3N3S3, it is prepared by reacting triphenylthiophenol and lithium salt as lithium hydroxide; if the lithium replenishing agent is Li2C... 16 H8F 12 S2 is composed of 3,5-trifluoromethylphenyl disulfide and lithium hydroxide as the lithium salt.

[0021] As a specific technical solution, in step S2, the pulverization method includes one or more combinations of air jet mill, mechanical mill, etc., and the particle size control D50≤20μm, preferably D50≤10μm, more preferably D50≤5μm.

[0022] As a specific technical solution, in step S3, the soaking or adsorption time can be 1, 5, 10, 12, 16, or 24 hours; initially, the longer the soaking time, the more adsorbed the lithium agent; after the adsorption exceeds 12 hours, the increase in the adsorption amount of the lithium agent is limited; the loading amount of the lithium agent is controlled at 5% to 90%; specifically, it can be 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any value therein.

[0023] As a specific technical solution, in step S4, the coating of the conductive agent can be carried out by wet coating, and the drying after coating can be spray drying, centrifugal drying, vacuum drying, heating drying, multi-stage drying, rotary drying, or pressure filtration drying.

[0024] As a specific technical solution, in step S5, the certain proportion of the mixture can be the positive electrode ratio of (93% ≤ positive electrode content ≤ 99%) + (0 < porous composite material containing lithium supplementer ≤ 5%) + (0 < conductive agent ≤ 4%) + (0 < binder ≤ 5%) + solvent (dry electrode does not require solvent) to prepare a total dry powder content of 100%; wherein the positive electrode can be 93%, 94%, 95%, 96%, 97%, 98%, 99% or any value thereof; the porous composite material containing lithium supplementer can be 0%, 1%, 2%, 3%, 4%, and 5% can be any of these values; the conductive agent can be 0%, 1%, 2%, 3%, and 4% or any of these values; the binder can be 0%, 1%, 2%, 3%, 4%, and 5% or any of these values; the negative electrode ratio is (92% ≤ negative electrode content ≤ 99%) + (0 < porous composite material containing lithium supplementation agent ≤ 5%) + (0 < conductive agent ≤ 4%) + (0 < binder ≤ 5%) + solvent (dry electrode does not require solvent) to prepare a dry powder with a total dry powder content of 100%.

[0025] The negative electrode content can be 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or any value thereof; the porous composite material containing lithium supplement can be 0%, 1%, 2%, 3%, 4%, 5%, or any value thereof; the conductive agent can be 0%, 1%, 2%, 3%, 4%, or any value thereof; the binder can be 0%, 1%, 2%, 3%, 4%, 5%, or any value thereof.

[0026] Thirdly, the present invention also provides the application of a porous composite material containing a lithium supplement agent or a composite material prepared by a method thereof in a battery, wherein the battery includes any one of a lithium-ion battery, a solid-state battery, and a semi-solid-state battery.

[0027] Compared with existing technologies, a porous composite material containing lithium replenishing agents can effectively address the poor electronic conductivity of organic lithium salt lithium replenishing agents and solve the problem of severe gas generation during long-term cycling caused by the aforementioned lithium replenishing materials remaining in the electrolyte system. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below. 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.

[0029] Unless otherwise specified, the experimental methods used in the examples and comparative examples are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0030] Example 1

[0031] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3 The D50 is 3 μm; the lithium-containing lithium supplementer is lithium benzimidazole-2-one; the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: 95% LFP + 2.5% lithium-containing composite material + 1.8% PVDF + 0.7% carbon nanotubes; the negative electrode composition is: 95.5% graphite + 1% SP + 0.5% carbon nanotubes + 1% CMC + 2% SBR; the preparation method of this composite material is as follows:

[0032] S1. Mix 1 mol of 2H-benzimidazol-2-one, 1.2 mol of lithium methoxide, and methanol (CH3OH) and reflux at 80 °C for 6 hours. After the reaction is complete, remove the methanol by rotary evaporation under reduced pressure. The resulting solid is then vacuum dried in a convection oven at 120 °C for 10 hours to obtain a yellowish-brown solid as the final product; this product is then dissolved in methanol to prepare a homogeneous solution of a certain concentration.

[0033] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0034] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0035] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0036] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0037] Example 2

[0038] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3 The D50 is 3 μm; the lithium-containing lithium supplementer is lithium trifluoromethanesulfonyl (LiSO2CF3); the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: 95% LFP + 2.5% lithium-containing composite material + 1.8% PVDF + 0.7% carbon nanotubes; the negative electrode composition is: 95.5% graphite + 1% SP + 0.5% carbon nanotubes + 1% CMC + 2% SBR; the preparation method of this composite material is as follows:

[0039] S1. Dissolve sodium trifluoromethanesulfonate in a mixed solution of acetonitrile and hydrochloric acid (1.2 equivalents). Add lithium hydroxide monohydrate (1.0 equivalent) in an ice bath and continue stirring for 30 minutes. Then, obtain the product by recrystallization and drying, and dissolve it in methanol to prepare a homogeneous solution of a certain concentration.

[0040] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0041] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0042] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0043] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0044] Example 3

[0045] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3The D50 is 3 μm; the lithium-containing lithium supplementer is pre-lithiated trithiocyanate Li3TCA; the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: LFP 95% + 2.5% lithium-containing composite material + PVDF 1.8% + carbon nanotubes 0.7%; the negative electrode composition is: graphite 95.5% + SP 1% + carbon nanotubes 0.5% + CMC 1% + SBR 2%; the preparation method of this composite material is as follows:

[0046] S1. Disperse / dissolve 1 mol of trithiocyanate, an organic precursor, in a solvent. Add lithium hydroxide in the corresponding molar ratio according to the chemical structural formula, disperse / dissolve in the solvent, stir and react for a period of time, then dry to remove moisture. Subsequently, purify multiple times and dissolve in methanol solvent to prepare a homogeneous solution of a certain concentration.

[0047] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0048] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0049] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0050] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0051] Example 4

[0052] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3 The D50 is 3 μm; the lithium-containing lithium supplementer is pre-lithiated triphenylthiophenol; the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: LFP 95% + 2.5% lithium-containing composite material + PVDF 1.8% + carbon nanotubes 0.7%; the negative electrode composition is: graphite 95.5% + SP 1% + carbon nanotubes 0.5% + CMC 1% + SBR 2%; the preparation method of this composite material is as follows:

[0053] S1. Disperse / dissolve 1 mol of the organic precursor triphenylthiophenol in a solvent. Add lithium hydroxide in the corresponding molar ratio according to the chemical structural formula, disperse / dissolve in the solvent, stir and react for a period of time, then dry to remove moisture. Subsequently, purify multiple times and dissolve in methanol solvent to prepare a homogeneous solution of a certain concentration.

[0054] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0055] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0056] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0057] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0058] Example 5

[0059] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3 The D50 is 3 μm; the lithium-containing lithium supplementer is lithium-ionized 3,5-trifluoromethylphenyl disulfide; the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: 95% LFP + 2.5% lithium-containing composite material + 1.8% PVDF + 0.7% carbon nanotubes; the negative electrode composition is: 95.5% graphite + 1% SP + 0.5% carbon nanotubes + 1% CMC + 2% SBR; the preparation method of this composite material is as follows:

[0060] S1. Disperse / dissolve 1 mol of the organic precursor 3,5-trifluorodisulfide in a solvent. Add lithium hydroxide in the corresponding molar ratio according to the chemical structural formula, disperse / dissolve in the solvent, stir and react for a period of time, then dry to remove moisture. Subsequently, purify multiple times and dissolve in methanol solvent to prepare a homogeneous solution of a certain concentration.

[0061] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0062] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0063] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0064] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0065] Example 6

[0066] This embodiment provides a porous composite material containing a lithium supplement, with a porous carbon content of 49.5% and a specific surface area of ​​1500 g / cm³. 3 The D50 is 3 μm; the lithium supplementer is lithium squaric acid; the loading is 50%; the conductive agent is single-arm carbon nanotubes, and the conductive agent slurry is 0.5% single-arm carbon nanotube slurry; the positive electrode composition is: 95% LFP + 2.5% composite material containing lithium supplementer + 1.8% PVDF + 0.7% carbon nanotubes; the negative electrode composition is: 95.5% graphite + 1% SP + 0.5% carbon nanotubes + 1% CMC + 2% SBR; the preparation method of this composite material is as follows:

[0067] S1. Grind 1 mol of squaric acid and 1 mol of lithium carbonate thoroughly in an agate mortar, then add deionized water and react magnetically at 60°C for 1 hour. After the reaction is complete, concentrate the solution by rotary evaporation at 65°C. The crude product is washed three times (20 mL each time) with anhydrous ethanol to remove residual H2C4O4. The purified lithium squaric acid (Li2C4O4) is then vacuum dried at 120°C for 6 hours to obtain a white crystalline powder as the final product, which is then dissolved in methanol to prepare a homogeneous solution of a certain concentration.

[0068] S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm;

[0069] S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed into the pores of the porous material, and the loading of the lithium supplement is controlled at 50%. Then, the porous carbon material containing the lithium supplement is prepared by drying.

[0070] S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing 0.5% conductive agent, and then dried;

[0071] S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

[0072] Comparative Example 1

[0073] Positive electrode composition: LFP 97.5% + PVDF 1.8% + carbon nanotubes 0.7%; Negative electrode composition: Graphite 95.5% + SP 1% + carbon nanotubes 0.5% + CMC 1% + SBR 2%; assembled into a 3Ah pouch cell.

[0074] The batteries from Examples 1-3 and Comparative Example 1 were tested at a 0.1C rate (2.8V-4.2V) and the first charge-discharge capacity and first efficiency after the addition of lithium replenishment were recorded.

[0075] Table 1 Test data for different embodiments

[0076] Example First charge capacity mAh / g Initial discharge capacity mAh / g First-time efficiency % 1 162.60 151.92 93.43% 2 162.47 151.79 93.42% 3 163.83 153.14 93.48% 4 165.72 155.03 93.55% 5 167.18 156.49 93.61% 6 165.84 155.16 93.56% Comparative Example 1 160.21 148.19 92.50%

[0077] As shown in Table 1 above, and in the comparative examples, the lithium iron phosphate battery without added lithium supplementation exhibits an initial efficiency of 92.5% and a charging capacity of 160.2 mAh / g at 0.1C rate, with a high discharge capacity of 148.19 mAh / g. In Example 1, however, even with a small amount of lithium supplementation, its charging capacity is only 162.6 mAh / g. The discharge capacity was 151.92 mAh / g, and the initial efficiency was 93.43%. Similarly, in Example 2, the combined positive electrode lithium replenishment capacity was 153.79 mAh / g with the same addition ratio, and the initial efficiency was improved to 93.42%. Example 3 had the highest lithium replenishment capacity, with the same addition amount resulting in an initial discharge capacity of 163.83 mAh / g and an initial efficiency of 93.48%. In Example 4, the combined positive electrode lithium replenishment capacity was 165.72 mAh / g with the same addition ratio, and the initial efficiency was improved to 93.55%. In Example 5, the combined positive electrode lithium replenishment capacity was 167.18 mAh / g with the same addition ratio, and the initial efficiency was improved to 93.61%. In Example 6, the combined positive electrode lithium replenishment capacity was 165.84 mAh / g with the same addition ratio, and the initial efficiency was improved to 93.56%. As can be seen from the above, the prepared organic lithium replenishing agents all have lithium replenishment effects, and lithium replenishment can be achieved according to different addition ratios.

[0078] The porous composite material containing lithium supplementation agent provided by this invention can be applied to batteries such as lithium-ion batteries, solid-state batteries, semi-solid-state batteries, and negative electrode-free batteries.

[0079] The above embodiments are merely illustrative of the concept and technical solution of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. The invention discloses a porous composite material containing a lithium supplement, which is composed of a porous carbon material a, a lithium supplement b, a reinforcing conductive material c, and a coating layer d that may or may not contain other elements; wherein a+b+c+d=100%, 10%≤a<100%, 0%<b≤90%, 0%≤c≤5%, and 0%≤d≤5%.

2. According to claim 1, the feature is that, The porous carbon material has a mass percentage (a) of 95% ≤ a < 100%; the porous carbon material can be activated carbon, porous carbon, mesoporous carbon, or other porous carbon materials / carbon framework materials; the morphology of the porous material is not limited to spherical, near-spherical, or other irregular particle morphologies; its specific surface area (BET) ranges from 200 g / m³. 3 ≤Specific surface area≤3000 g / m 3 The pore size is ≤100nm; the precursor of the porous carbon material can be one or more of the following: biomass materials, polymer materials, starch and polysaccharides, coal-based materials, pitch-based materials, organic framework materials, etc. Among them, biomass materials include but are not limited to walnut shells, coconut shells, fruit shells, grapefruit peels, apricot shells, mangosteen shells, reeds, bamboo, pine cone shells, nut shells, peanut shells, macadamia nut shells, lychee shells; tree branches such as lychee wood, apple wood, pine wood, apricot wood, etc.; polymer materials include but are not limited to one or more of the following: phenolic resin, furan resin, epoxy resin, polyacrylonitrile, polyethylene, polyfurfuryl alcohol, polyvinylpyrrolidone, polypropylene, polyimide resin, pitch-based resin and cellulose resin; pitch-based includes petroleum pitch and coal pitch; organic framework materials include but are not limited to one or more of the following: MOF, COF, etc.

3. According to claim 1, the lithium replenishing agent is mainly an organic lithium replenishing agent, mainly including lithium squaric acid (Li₂C₄O₄), lithium oxalate (Li₂C₂O₄), lithium borate oxalate (Li₂B₂(C₂O₄)₂), and lithium phosphate oxalate (Li₃PO₄·Li₂C₂O₄). Or related complex salts, lithium malonate: Li₂C₃H₂O₄, lithium succinate, lithium citrate, dilithium dihydroxyterephthalate derivatives: such as Li₄C₈H₂O₆, butyllithium, phenyllithium, Li-hydrazine complexes: such as Li(N₂H₄), lithium citrate, lithium tartrate, Li₂DHBN and Li₂BX₃N (X=F, Cl, Br, I), LiBH₃X (X=F, Cl, Br, I), lithium 2,6-pyridinedicarboxylate (Li₂PDC), lithium ethylenediaminetetraacetate (Li₄EDTA delithiation potential < 3.8V), if it is an insoluble lithium supplement, a dispersing agent can be added; lithium-naphthalene solutions that are solutions themselves: composed of metallic lithium and naphthalene (C 10 H8) reacts in ether solvents (such as DME, THF) to form a deep blue solution, with a delithiation potential of approximately 0.5–0.7 V. Li-biphenyl (C 12 H 10 It reacts with lithium to form a green solution, and the reduction potential can be reduced to 0.13V or a combination of one or more of the following: Li-2-methylbiphenyl solution, Li-bipyridine solution, (lithium complexes of 4,4′-dimethylbiphenyl, 2-methylbiphenyl and 3,3′,4,4′-tetramethylbiphenyl), 12-crown ether 4-lithium complex, [2.2.1]-cryptoether-lithium complex, benzimidazole-2-one lithium (Li2N2C7H4O), lithium trifluoromethanesulfonyl (LiSO2CF3), pre-lithiated trithiocyanate Li3TCA with a delithiation potential of 3.7V, pre-lithiated triphenylthiophenol with a delithiation potential of 2.8V; and lithiated disulfide-3,5-trifluoromethylphenyl, etc.

4. According to claim 1, the enhanced conductive material is mainly an inorganic carbon material, including single-arm and multi-arm carbon nanotubes, conductive carbon black, graphene, etc. A composite of at least one or more of graphite, fullerene, VGCF, amorphous carbon, soft carbon, and hard carbon.

5. According to claim 1, the coating layer may or may not be included, for improving the performance of the material; the thickness of the coating layer may be 0 nm ≤ coating thickness ≤ 50 nm; the coating amount 0 ≤ d is ≤ 1% of the total mass of the material; the coating elements may include one or more of the following composite elements: C, H, O, P, Li, B, N, Mg, Al, F, Si, P, S, K, Ca, Sc, V, Ti, Cr, Mn, Ni, Ga, Ge, La, Se, Rb, Sr, Y, Nb, Mo, Ru, Eu, Er, Yb, Dy, Cs, Sb, Sn, Se, Te, Bi, Zn, Cu, Ce, Rh, Tb, Lu, Hf, Ta, W, Os, Ir, Pt, Au, Pb, Zr, Cd, Pd, Ag, etc.

6. This invention also discloses a method for preparing a porous composite material containing a lithium supplement, characterized in that... Includes the following steps: S1. The synthesis of the lithium supplement agent in claim 3 above, and its dissolution in a solvent to prepare a homogeneous solution of a certain concentration; S2. The porous carbon material is crushed and sieved to control the particle size D50≤20μm; S3. The porous carbon material is immersed in the solution of S1 above. After immersion for a certain period of time, the lithium supplement is adsorbed in the pores of the porous material. The loading amount of the lithium supplement is controlled. Then, the porous carbon material containing the lithium supplement is prepared by drying. S4. Further dry the above materials; after drying, the above materials can be further coated with other coating elements (which may or may not be contained) and a slurry containing a conductive agent, and then dried; S5. Mix the S4 material with the positive and negative electrode materials, conductive agent, binder, and solvent system in a certain proportion; apply it to the current collector, dry it, assemble it into a battery, and then test its performance.

7. The preparation method according to claim 6, characterized in that, In step S1, the synthesis of lithium supplements involves different precursors. For example, lithium trifluoromethanesulfonyl trifluoromethanesulfonate (LiSO2CF3) is prepared by reacting sodium trifluoromethanesulfonate with lithium hydroxide in an ice bath; lithium benzimidazole-2-one lithium (Li2N2C7H4O) is prepared by reacting 2H-benzimidazole-2-one (C7H6N2O) with lithium salt (lithium methoxide CH3OLi); lithium squaric acid is prepared by reacting squaric acid with lithium carbonate; lithium trithiocyanate (Li3C6H3S3) is prepared by reacting trithiocyanate with lithium salt as lithium hydroxide; lithium triphenylthiophenol (Li3C3N3S3) is prepared by reacting triphenylthiophenol with lithium salt as lithium hydroxide; and lithium triphenylthiophenol (Li2C6H3S3) is prepared by reacting triphenylthiophenol with lithium salt as lithium hydroxide. 16 H8F 12 S2 is composed of 3,5-trifluoromethylphenyl disulfide and lithium hydroxide as the lithium salt; the lithium salt can be one or more of lithium hydroxide, lithium carbonate, hydrated lithium hydroxide, lithium nitrate, lithium oxide, lithium methoxide, lithium ethanol, butyllithium, lithium citrate, lithium phosphate, etc.; the specific synthesis method will be shown in the examples; moreover, the concentration of the good solvent and homogeneous solution of different lithium replenishing agents are different. Generally speaking, the concentration of the lithium replenishing agent solution is ≤ the saturation concentration of the lithium replenishing agent; characterized in that the loading amount of lithium replenishing agent in step S3 is between 5% and 90%.

8. The preparation method according to claim 6, characterized in that, In step S4, the conductive agent slurry contains a conductive agent, a solvent, a polymer material, and a dispersant, etc.; wherein the conductive agent is as described in claim 3; the solvent can be water, NMP, methanol, ethanol, acetone, toluene, DMF, DMAC, n-heptane, ACN, ethyl acetate, isobutyl isobutyrate, xylene and anisole, n-hexane, alkanes, etc., and organic solvents. The polymer matrix can be polyethers [containing (—C—O—C—) such as PEO, PPO, PEO-PPO copolymers, PEO-PS copolymers, multi-arm polyethers, star-shaped, dendritic polyethers, and supramolecular polymers synthesized from polyether units], PVP, CMC, CMC-Li, NBR, HNBR, PU-PAA (polyacrylic soft segment / modified polyurethane), polyimide PI, polycarbonates [such as polytrimethylene carbonate, polyvinyl carbonate, polycarbonate (PVC, PTMC, PPC), polyacrylic acrylate (PECA), polypropylene glycol (PMA)], polyacrylates (especially polyacrylate electrolytes containing ethylene oxide segments at the chain ends, acrylic units, methyl acrylate, propylene glycol) The following are included in the following categories: ethyl acetate, butyl acrylate and copolymers with other monomers containing double or triple bonds; polyacrylonitrile and copolymers with other monomers containing double or triple bonds; polysiloxanes (polymers containing -Si-O-Si- structures and polymers with other monomers containing double bonds); polyurethanes (polymers containing urethane or urethane structures); and single-ion conductor polymer systems of the above polymer systems; polyvinylidene chloride (PVDF, PVDF-HFP and their modified systems); if the above materials are polymer solid electrolytes, their ion conductivity can be further improved; the dispersant can be one or more of anionic dispersants, cationic dispersants, amphoteric dispersants, and polymeric dispersants.

9. The preparation method according to claim 6, characterized in that, In step S5, the positive electrode material in the positive and negative electrode materials is lithium iron phosphate, lithium manganese iron phosphate, lithium-rich manganese-based materials, ternary materials (any ratio of NCM and NCA monocrystalline or polycrystalline materials, and multi-element materials modified with ternary materials as the main structure); lithium cobalt oxide positive electrode material, and cobalt-free layered positive electrode material; wherein the layered ternary positive electrode material has the structural formula LiNi. x Co y M 1-x-y O2, where M is at least one of Mn, Al, W, Zr, Mg, B, Nb, Ta, Mo, La, and Ti, 0.33≤x≤1.0, 0≤y≤0.33, and the structural formula of the ternary material modified by the ternary material is LiNi. x Co y M z N 1-x-y-z O2, wherein M is at least one of Mn, Al, W, Zr, Mg, B, Nb, Ta, Mo, La, and Ti, 0.33≤x≤1, 0≤y≤0.33, 0≤z≤0.33, and N is one or more of Mn, Al, W, Zr, Mg, B, Nb, Ta, Mo, La, and Ti, and M and N are not simultaneously of the same element; the binder content is 0≤binder≤5%; the binder includes one or more of wet binders (polyacrylate / ester, cellulose, etherified cellulose, polycarbonate, silicone rubber, polyurethane, SBR, NBR, PVDF, SBS, SEBS, PVDF-HFP), dry binders (TPA, PTFE, PEO), etc.; the negative electrode material is graphite, artificial graphite, natural graphite, hard carbon. The anode material comprises amorphous carbon, silicon anode, silicon-oxygen, silicon-carbon anode, CVD silicon-carbon anode, lithium metal, and anode-free material; the conductive agent is as described in claim 4; the positive electrode ratio is (93% ≤ positive electrode content ≤ 99%) + (0 < porous composite material containing lithium supplementation agent ≤ 5%) + (0 < conductive agent ≤ 4%) + (0 < binder ≤ 5%) + solvent (dry electrode does not require solvent); the total dry powder content is 100%; the negative electrode ratio is (92% ≤ negative electrode content ≤ 99%) + (0 < conductive agent ≤ 4%) + (0 < binder ≤ 5%) + solvent (dry electrode does not require solvent); the current collector is copper, aluminum, composite current collector, stainless steel current collector of different thicknesses, and carbon-coated current collector after carbon coating treatment of the above current collectors.

10. The application of a porous carbon material, an enhanced conductive material, a composite material containing or without other elemental coating layers, or a porous composite material containing a lithium supplement agent prepared by any one of the preparation methods of claims 1 to 9 in electrode sheets, batteries, battery packs, and electrical devices, wherein the battery includes any one of lithium-ion batteries, dry electrodes, solid-state batteries, semi-solid-state batteries, and negative electrode-free batteries.