CN114335460A - Quick-filling graphite composite material and preparation method thereof - Google Patents
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Abstract
The invention relates to a quick-charging graphite composite material and a preparation method thereof, wherein the quick-charging graphite composite material comprises an inner shell and an outer shell, the outer shell comprises inorganic lithium salt, a carbon nano tube and the balance of amorphous carbon, the inner core comprises porous graphite and solid electrolyte, one part of the solid electrolyte is embedded between layers of the porous graphite, and the other part of the solid electrolyte is attached to the surface of the porous graphite; according to the invention, the high ionic conductivity of the solid electrolyte, the high electronic conductivity of the carbon nano tube and the three-dimensional lithium-embedding channel characteristic of the inorganic lithium salt are utilized, so that the transmission rate of lithium ions can be improved, the quick charge performance of the material is improved, and the expansion is reduced; the preparation method is favorable for improving the binding force between the solid electrolyte and the inorganic lithium salt, can enhance the stability of the inner shell structure, better protects the quick-charging graphite composite material, reduces the loss of the capacity of the material and improves the cycle performance.
Description
Technical Field
The invention relates to the technical field of lithium ion battery material preparation, in particular to a quick-charging graphite composite material and a preparation method thereof.
Background
With the increasing demand of the market on the quick charge capacity and the increase of the endurance mileage of the lithium ion battery, the quick charge performance of the lithium ion battery cathode material is greatly improved while the lithium ion battery cathode material has high energy density;
at present, graphite is generally used as a negative electrode of a lithium electronic battery, the surface of the graphite is coated with soft carbon or hard carbon, and the material is mainly subjected to intercalation/deintercalation of lithium ions along the interlayer of the material in the charging and discharging processes, so that the problems of long path, easiness in expansion and the like exist, the transmission efficiency and the diffusion rate of the lithium ions are limited, and the volume expansion of the material is serious.
In order to solve the problem, researchers improve the lithium ion intercalation and deintercalation rate of the material by coating the surface of the material with a solid electrolyte or a conductive agent and a lithium salt; for example, patent CN202110771316.0 discloses a solid electrolyte coated graphite composite material, a preparation method and application thereof, and a lithium ion battery. The preparation process comprises the following steps: (1) preparing a composite material comprising a solid electrolyte; preparing an inner core comprising graphite; preparing a mixed solution containing resin; (2) forming a first shell layer on a core by adopting a magnetron sputtering method, wherein the core comprises graphite as a substrate, and a composite material comprising a solid electrolyte as a target material; and then mixing the graphite powder with a mixed solution containing resin, drying and then carbonizing to form a second outer shell layer to obtain the solid electrolyte coated graphite composite material. In the patent, although the quick charge performance of the composite material is improved, the core expands greatly in the charge and discharge process, the intercalation and deintercalation rate is slow, and meanwhile, the electronic conductivity of the solid electrolyte on the outer layer deviates, so that the rate capability and the cycle performance of the solid electrolyte are influenced.
Disclosure of Invention
Based on this, it is necessary to provide a fast-filling graphite composite material and a preparation method thereof to solve the problems in the prior art.
A quick-charging graphite composite material comprises an inner shell 90 wt% -100 wt% and an outer shell 1 wt% -10 wt%, wherein the outer shell comprises inorganic lithium salt, carbon nano tubes and the balance of amorphous carbon, the inner core comprises porous graphite and solid electrolyte, one part of the solid electrolyte is embedded between layers of the porous graphite, the other part of the solid electrolyte is attached to the surface of the porous graphite,
the mass of the solid electrolyte in the inner shell accounts for 1 wt% -10 wt%.
In one embodiment, the solid electrolyte is one or more of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium titanium aluminum phosphate, lithium titanium phosphate, and lithium zinc germanate.
In one embodiment, the shell comprises 5 wt% to 20 wt% of inorganic lithium salt, 1 wt% to 5 wt% of carbon nanotubes, and the balance amorphous carbon.
In one embodiment, the inorganic lithium salt is one or more of lithium zirconate, lithium niobate, and lithium titanate.
According to the rapid-charging graphite composite material, the solid electrolyte is doped in the inner core, and the advantages of high ionic conductivity and low expansion rate of the solid electrolyte are utilized, so that the rapid-charging performance of the material is improved, and the expansion is reduced; meanwhile, the high ionic conductivity of the solid electrolyte, the high electronic conductivity of the carbon nano tube and the three-dimensional lithium-embedded channel characteristic of the inorganic lithium salt are utilized, the quick charging performance of the graphite composite material can be further improved, and the solid electrolyte can enhance the stability of the core structure and improve the cycle performance of the core structure in a mode of combining chemical bonds with porous graphite.
A preparation method of a quick-filling graphite composite material comprises the following steps:
s1: adding graphite into an oxidant solution, and soaking for 24 hours;
s2: adding 0.5-5% sodium carbonate solution into S1, stirring uniformly, heating for 1-6 h at 50-100 ℃, and filtering;
s3: sintering the substance obtained in the step S2 at the temperature of 200-300 ℃ to obtain a porous graphite material;
s4: adding the porous graphite material obtained in the step S3 into an organic solvent containing a solid electrolyte with the concentration of 1% -10%, and uniformly stirring;
s5: reacting in a high-pressure reaction kettle at the temperature of 150-200 ℃ for 3-6 h, doping the solid electrolyte in a porous graphite material, filtering and drying to obtain a precursor composite material A, namely the inner shell;
s6: weighing the composite material A and the asphalt according to the mass percentage, mixing the composite material A and the asphalt, grinding, and then carbonizing for 6-12 hours at the temperature of 800 ℃ to obtain a composite material B;
s7: soaking the composite material B in 0.5-2% concentration catalyst water solution, filtering and drying;
s8: depositing carbon nanotubes by vapor deposition;
s9: and depositing inorganic lithium salt on the surface of the graphite composite material by a particle injection method to obtain the graphite composite material.
In one embodiment, the oxidant is one or more of potassium permanganate, potassium perchlorate, concentrated sulfuric acid, ferric trichloride and concentrated nitric acid,
the organic solvent is one or more of absolute ethyl alcohol, ethylene glycol ether and triethanolamine,
the catalyst is one or more of nickel nitrate, cobalt nitrate and ferric nitrate.
In one embodiment, the ratio of the graphite, the oxidant solution, the sodium carbonate solution and the solid electrolyte is 100: (1-10): (1-10): (1-10).
In one embodiment, in the step S6, the proportion of the composite material A to the asphalt is 100 (5-15).
In one embodiment, in the step S7, the proportion of the composite material B and the catalyst is (0.5-2) in a mass ratio of 100.
In one embodiment, the carbon source of the vapor deposition method is one of methane, ethane and ethylene, the temperature is 800 ℃, the time is 6h,
the particle injection method is carried out in an oxygen atmosphere, the gas flow is 1 sccm-10 sccm, and the gas pressure is 1 × 10sccm-4Pa～10×10-4Pa, injection temperatureThe temperature is 100-500 ℃, and the time is 10-120 min.
According to the preparation method of the quick-filling graphite composite material, after the oxidant is oxidized on the surface of graphite to generate hydroxyl or carboxyl, the sodium carbonate solution is added to react, the filtering and the sintering are carried out, wherein the sodium carbonate forms holes after the sintering to obtain a porous graphite structure, then the solid electrolyte is doped in the porous graphite structure, one part of the solid electrolyte is embedded between the layers of the graphite, and the other part of the solid electrolyte is on the surface of the graphite, so that the stability of the core structure is improved, and the cycle performance of the core structure is improved.
Further, the asphalt is carbonized at 800 ℃ to form amorphous carbon, so that the amorphous carbon coats the inner shell, and the stability of the structure is facilitated; the carbon nano tube is deposited by the vapor deposition method, so that the density of deposition is improved, the impedance of the deposition is reduced, and meanwhile, the vapor deposition method has the advantages of high consistency and good deposition uniformity; in addition, the particle injection method can better protect the quick-charging graphite composite material, improve the coating uniformity of the material, accurately control the deposition amount and the deposition depth of the inorganic lithium salt, and simultaneously improve the binding force between the solid electrolyte and the inorganic lithium salt, thereby improving the cycle performance of the quick-charging graphite composite material and reducing the expansion of the material in the cycle process.
Drawings
Fig. 1 is an SEM image of a rapid-charging graphite composite material according to the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.
In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
A quick-charging graphite composite material comprises an inner shell and an outer shell, wherein the outer shell comprises 5 wt% -20 wt% of inorganic lithium salt, 1 wt% -5 wt% of carbon nano tubes and the balance of amorphous carbon, and the inorganic lithium salt is one or more of lithium zirconate, lithium niobate and lithium titanate.
Further, the inner core comprises porous graphite and a solid electrolyte, wherein the solid electrolyte accounts for 1 wt% -10 wt% of the specific gravity in the inner shell, one part of the solid electrolyte is embedded between the layers of the porous graphite, the other part of the solid electrolyte is attached to the surface of the porous graphite, the stability of the inner core structure is favorably improved, and the solid electrolyte is one or more of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, titanium aluminum lithium phosphate, titanium lithium phosphate and zinc lithium germanate.
Further, in order to improve the cycle performance of the rapid graphite composite material and reduce the expansion of the material in the cycle process, the invention provides a preparation method of the rapid graphite composite material, which comprises the following steps:
s1: adding graphite into an oxidant solution, and soaking for 24 hours;
s2: adding 0.5-5% sodium carbonate solution into S1, stirring uniformly, heating for 1-6 h at 50-100 ℃, and filtering;
s3: sintering the substance obtained in the step S2 at the temperature of 200-300 ℃ to obtain a porous graphite material;
s4: adding the porous graphite material obtained in the step S3 into an organic solvent containing a solid electrolyte with the concentration of 1% -10%, and uniformly stirring;
s5: reacting in a high-pressure reaction kettle at the temperature of 150-200 ℃ for 3-6 h, doping the solid electrolyte in a porous graphite material, filtering and drying to obtain a precursor composite material A, namely the inner shell;
s6: weighing the composite material A and the asphalt according to the mass percentage, mixing the composite material A and the asphalt, grinding, and then carbonizing for 6-12 hours at the temperature of 800 ℃ to obtain a composite material B; wherein the proportion of the composite material A to the asphalt is 100 (5-15).
S7: soaking the composite material B in 0.5-2% concentration catalyst water solution, filtering and drying; wherein the proportion of the composite material B to the catalyst is 100 (0.5-2).
S8: depositing the carbon nano tube by a vapor deposition method, wherein specifically, a carbon source of the vapor deposition method is one of methane, ethane and ethylene, the temperature is 800 ℃, and the time is 6 h;
s9: depositing inorganic lithium salt on the surface of the graphite composite material by a particle injection method to obtain a graphite composite material; in the process of depositing the inorganic lithium salt, the particle injection method is performed in an oxygen atmosphere, with a gas flow rate of 1sccm to 10sccm and a gas pressure of 1 × 10- 4Pa～10×10-4Pa, the injection temperature is 100-500 ℃, and the time is 10-120 min.
In the preparation method, the ratio of the graphite, the oxidant solution, the sodium carbonate solution and the solid electrolyte is 100: (1-10): (1-10): (1-10).
Further, the oxidant is one or more of potassium permanganate, potassium perchlorate, concentrated sulfuric acid, ferric trichloride and concentrated nitric acid; the organic solvent is one or more of absolute ethyl alcohol, ethylene glycol ether and triethanolamine; the catalyst is one or more of nickel nitrate, cobalt nitrate and ferric nitrate.
Example 1
Firstly, 100ml of potassium perchlorate solution with the concentration of 1 percent is measured, 100g of artificial graphite is put into the potassium perchlorate solution and soaked for 24 hours; then weighing 500ml of 1% sodium carbonate solution, adding the solution after soaking for 24h into the sodium carbonate solution, stirring uniformly, heating for 3h at the temperature of 80 ℃, filtering, and sintering for 6h at the temperature of 250 ℃ to obtain the porous graphite material.
Further, 100ml of triethanolamine containing 5% lithium lanthanum zirconium oxygen is measured, the porous graphite material is placed into the triethanolamine and uniformly stirred, then the reaction is carried out in a high-pressure reaction kettle at the temperature of 180 ℃ for 3 hours, so that the solid electrolyte is doped into the porous graphite material, and then the porous graphite material is filtered and dried to obtain a precursor composite material A, namely the inner shell.
Further, 100g of the composite material A and 10g of asphalt were weighed and mixedGrinding after uniform mixing, and then carbonizing at 800 ℃ for 12h to obtain a composite material B; then, 100ml of 1% nickel nitrate aqueous solution is measured, the composite material B is placed into the nickel nitrate aqueous solution, and the mixture is stirred uniformly, filtered and dried; then, depositing the carbon nano tube by a vapor deposition method, wherein specifically, a carbon source of the vapor deposition method is one of methane, ethane and ethylene, the temperature is 800 ℃, and the time is 6 hours; finally, inorganic lithium salt is deposited on the surface of the lithium ion battery by a particle injection method, wherein the particle injection method is carried out in an oxygen atmosphere, the gas flow is 5sccm, and the gas pressure is 5 × 10-4Pa, the injection temperature is 300 ℃, and the time is 60min, thereby obtaining the quick-filling graphite composite material.
Example 2
Firstly, weighing 500ml of 1% potassium permanganate solution, putting 100g of artificial graphite into the potassium permanganate solution, and soaking for 24 hours; then 200ml of 0.5% sodium carbonate solution is measured, the solution after 24h of soaking is added into the sodium carbonate solution, the mixture is stirred evenly, heated for 6h at the temperature of 50 ℃, filtered and sintered for 6h at the temperature of 200 ℃ to obtain the porous graphite material.
Further, 100ml of triethanolamine containing 1% lithium, lanthanum and titanium oxide is measured, the porous graphite material is placed into the triethanolamine and uniformly stirred, then the reaction is carried out in a high-pressure reaction kettle at the temperature of 150 ℃ for 6 hours, so that the solid electrolyte is doped into the porous graphite material, and then the porous graphite material is filtered and dried to obtain a precursor composite material A, namely the inner shell.
Further, 100g of the composite material A and 5g of asphalt are weighed, uniformly mixed, ground and carbonized at the temperature of 800 ℃ for 12 hours to obtain a composite material B; then, 100ml of 0.5% cobalt nitrate aqueous solution is measured, the composite material B is placed into the nickel nitrate aqueous solution, and the mixture is stirred uniformly, filtered and dried; then, depositing the carbon nano tube by a vapor deposition method, specifically, using ethane as a carbon source of the vapor deposition method, wherein the temperature is 800 ℃, and the time is 6 h; finally, an inorganic lithium salt is deposited on the surface thereof by a particle implantation method, wherein the particle implantation method is performed under an oxygen atmosphereGas flow of 1sccm and gas pressure of 1 × 10-4Pa, the injection temperature is 100 ℃, and the time is 120min, thereby obtaining the quick-filling graphite composite material.
Example 3
Firstly, weighing 1000ml of 1% ferric trichloride solution, putting 100g of artificial graphite into potassium permanganate solution, and soaking for 24 hours; then 100ml of 5% sodium carbonate solution is measured, the solution after 24h of soaking is added into the sodium carbonate solution, the mixture is stirred evenly, heated for 1h at the temperature of 100 ℃, filtered and sintered for 6h at the temperature of 300 ℃, and the porous graphite material is obtained.
Further, 100ml of triethanolamine containing 10% lithium aluminum titanium phosphate is measured, the porous graphite material is placed into the triethanolamine and uniformly stirred, then the reaction is carried out in a high-pressure reaction kettle at the temperature of 200 ℃ for 6 hours, so that the solid electrolyte is doped into the porous graphite material, and then the porous graphite material is filtered and dried to obtain a precursor composite material A, namely the inner shell.
Further, 100g of the composite material A and 15g of asphalt are weighed, uniformly mixed, ground and carbonized at the temperature of 800 ℃ for 6 hours to obtain a composite material B; then, 100ml of 2% ferric nitrate aqueous solution is measured, the composite material B is placed into nickel nitrate aqueous solution, and the mixture is filtered and dried after being uniformly stirred; then, depositing the carbon nano tube by a vapor deposition method, specifically, using ethylene as a carbon source, and setting the temperature at 800 ℃ and the time at 6 h; finally, inorganic lithium salt is deposited on the surface of the lithium ion battery by a particle injection method, wherein the particle injection method is carried out in an oxygen atmosphere, the gas flow is 10sccm, and the gas pressure is 10 multiplied by 10-4Pa, the injection temperature is 500 ℃, and the time is 10min, thereby obtaining the quick-filling graphite composite material.
Comparative example:
uniformly mixing 100g of artificial graphite, 20g of asphalt and 5g of lithium titanium aluminum phosphate, transferring the mixture into a tubular furnace, heating to 150 ℃ in an argon atmosphere, pre-carbonizing for 1h, heating to 800 ℃, and carbonizing for 6h to obtain the graphite composite material.
According to the national standard GB/T-243354 2019 graphite cathode material for lithium ion batteries, the following performance tests are carried out on the examples and the comparative examples:
(1) SEM detection
Example 1 was subjected to SEM test and the results are shown in figure 1.
From this, it is clear that the rapidly-filled graphite composite material obtained in example 1 is in the form of particles having a particle size of 5 to 15 μm and a uniform size distribution.
(2) And (3) button cell testing:
the fast-charging graphite composite materials prepared in examples 1-3 and the graphite composite material of the comparative example were assembled into button cells respectively according to the following methods:
firstly, adding a binder, a conductive agent and a solvent into a graphite composite material, uniformly stirring and mixing to prepare negative electrode slurry, coating the negative electrode slurry on a copper foil, drying, rolling, and cutting to prepare a negative electrode sheet; the graphite composite material comprises a graphite composite material, a conductive agent, a solvent and a binder, wherein the binder is LA132 binder, the conductive agent is SP conductive agent, and the solvent is secondary distilled water, wherein the weight ratio of the graphite composite material to the SP conductive agent to the LA132 binder is 92:3: 5.
Then, a metal lithium sheet is taken as a counter electrode, a Polyethylene (PE) film, a polypropylene (PP) film or a polyethylene propylene (PEP) composite film is taken as a diaphragm, and LiPF is taken6The electrolyte is/EC + DEC, and the cell assembly is carried out in an argon-filled glove box, wherein LiPF6Has a concentration of 1.1mol/L and a volume ratio of EC to DEC of 1: 1.
Finally, the prepared button cell is respectively arranged on a cell program control tester, and is charged and discharged at the charging and discharging multiplying power of 0.1C, the voltage range of charging and discharging is 0.001V to 2.0V, and the first discharge capacity and the first discharge efficiency are measured; the 3C rate discharge capacity of the graphite composite material was tested, the full-charge expansion of the graphite composite material negative electrode piece was tested, and the test results are shown in Table 1:
TABLE 1
As can be seen from Table 1, the first discharge capacity and the first discharge efficiency of the quick-charging graphite composite materials prepared in examples 1-3 are significantly higher than those of the comparative examples; in examples 1 to 3, the powder conductivity and the rate discharge capacity of 3C were both higher than those of the comparative example, and the full electrical expansion was also significantly lower than that of the comparative example.
(3) Pouch cell testing
Negative electrodes were prepared from the rapid graphite composite materials prepared in examples 1 to 3 and comparative example, respectively, and a ternary material (LiNi)1/3Co1/3Mn1/3O2) Preparing a positive electrode from a positive electrode material by using LiPF6(the solvent is EC + DEC, the volume ratio is 1:1, and the concentration is 1.3mol/L) is electrolyte, and Celgard2400 or other products of Celgard series are separators to prepare the 2Ah flexible package battery.
When the negative electrode is prepared, adding a binder, a conductive agent and a solvent into the quick-charging graphite composite material, stirring and mixing uniformly to prepare negative electrode slurry, coating the negative electrode slurry on copper foil, drying, rolling and cutting to prepare a negative electrode sheet; wherein the solvent is secondary distilled water, and the weight ratio of the quick-filling graphite composite material, the conductive agent, the binder and the secondary distilled water is 95:1:4: 220.
When the anode is prepared, the binder, the conductive agent and the solvent are added into the anode material, the anode material is uniformly stirred and mixed to prepare anode slurry, the anode slurry is coated on an aluminum foil, and the anode slurry is dried, rolled and cut to prepare the anode sheet, wherein the weight ratio of the anode material to the conductive agent to the binder to the solvent is 93:3:4: 140.
1) Rate capability test
The charging and discharging voltage range is 2.8-4.2V, the testing temperature is 25 +/-3.0 ℃, charging is carried out at 1.0C, 2.0C, 3.0C and 5.0C respectively, discharging is carried out at 1.0C, the constant current ratio and the temperature of the battery under different charging modes are tested, and the results are shown in Table 2:
TABLE 2
As can be seen from table 2, the rate charging performance of the pouch batteries prepared according to examples 1 to 3 is significantly better than that of the comparative example, and the charging time is shorter, indicating that the rapid-charging graphite composite material of the present invention has good rapid-charging performance.
In the process, because the battery needs the migration of lithium ions in the charging process, the surface of the quick-charging graphite composite material in the embodiment contains lithium salt, the lithium salt can facilitate the insertion and the extraction of the lithium ions, and the multiplying power performance of the lithium ion battery is improved; in addition, the particle injection method can better protect the quick-filling graphite composite material, thereby improving the coating uniformity of the material.
2) Cycle performance test
The following experiment was performed on the pouch batteries manufactured using the graphite composite materials of examples 1 to 3 and comparative example: the capacity retention rate was measured by performing 100, 300, and 500 charge-discharge cycles in sequence at a charge-discharge rate of 2C/2C and a voltage range of 2.8-4.2V, and the results are shown in Table 3:
TABLE 3
As can be seen from table 3, the pouch cells made in examples 1-3 had significantly higher cycle performance at each stage than the comparative example.
In summary, in the fast-charging graphite composite material, the solid electrolyte is doped in the core, and the first charge-discharge efficiency of the material is improved by utilizing the characteristics of high ionic conductivity of the solid electrolyte, high electronic conductivity of the carbon nano tube and three-dimensional lithium-embedded channel of the inorganic lithium salt, so that the fast-charging performance of the material is improved, and the expansion is reduced; and the solid electrolyte is combined with the porous graphite through a chemical bond, so that the stability of the core structure is improved, and the cycle performance of the core structure is improved.
Furthermore, the preparation method enables the amorphous carbon to coat the inner shell, so that the stability of the structure of the inner shell can be further improved; the carbon nano tube is deposited by a vapor deposition method, so that the density of the deposit is improved, the impedance of the deposit is reduced, the transmission rate of lithium ions is improved, and the cycle performance of the battery is improved; in addition, the inorganic lithium salt is deposited on the surface of the composite material by a particle injection method, so that the binding force between the solid electrolyte and the inorganic lithium salt is favorably improved, the quick-charging graphite composite material can be well protected, and the loss of the capacity of the material is reduced, so that the cycle performance of the quick-charging graphite composite material is improved, and the expansion of the material in the cycle process is reduced.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A quick-charging graphite composite material is characterized by comprising an inner shell 90 wt% -100 wt% and an outer shell 1 wt% -10 wt%, wherein the outer shell comprises inorganic lithium salt, carbon nano tubes and the balance of amorphous carbon, the inner core comprises porous graphite and solid electrolyte, one part of the solid electrolyte is embedded between layers of the porous graphite, the other part of the solid electrolyte is attached to the surface of the porous graphite,
the mass of the solid electrolyte in the inner shell accounts for 1 wt% -10 wt%.
2. The rapid-charging graphite composite material according to claim 1, wherein the solid electrolyte is one or more of lithium lanthanum zirconium oxygen, lithium lanthanum titanium oxygen, lithium titanium aluminum phosphate, lithium titanium phosphate, and lithium zinc germanate.
3. The rapid-charging graphite composite material according to claim 2, wherein the shell comprises 5 wt% to 20 wt% of inorganic lithium salt, 1 wt% to 5 wt% of carbon nanotubes, and the balance amorphous carbon.
4. The rapid-charging graphite composite material according to claim 3, wherein the inorganic lithium salt is one or more of lithium zirconate, lithium niobate, and lithium titanate.
5. The preparation method of the quick-filling graphite composite material according to claim 4, characterized by comprising the following steps:
s1: adding graphite into an oxidant solution, and soaking for 24 hours;
s2: adding 0.5-5% sodium carbonate solution into S1, stirring uniformly, heating for 1-6 h at 50-100 ℃, and filtering;
s3: sintering the substance obtained in the step S2 at the temperature of 200-300 ℃ to obtain a porous graphite material;
s4: adding the porous graphite material obtained in the step S3 into an organic solvent containing a solid electrolyte with the concentration of 1% -10%, and uniformly stirring;
s5: reacting in a high-pressure reaction kettle at the temperature of 150-200 ℃ for 3-6 h, doping the solid electrolyte in a porous graphite material, filtering and drying to obtain a precursor composite material A, namely the inner shell;
s6: weighing the composite material A and the asphalt according to the mass percentage, mixing the composite material A and the asphalt, grinding, and then carbonizing for 6-12 hours at the temperature of 800 ℃ to obtain a composite material B;
s7: soaking the composite material B in 0.5-2% concentration catalyst water solution, filtering and drying;
s8: depositing carbon nanotubes by vapor deposition;
s9: and depositing inorganic lithium salt on the surface of the graphite composite material by a particle injection method to obtain the graphite composite material.
6. The method for preparing the quick-charging graphite composite material according to claim 5, wherein the oxidant is one or more of potassium permanganate, potassium perchlorate, concentrated sulfuric acid, ferric trichloride and concentrated nitric acid,
the organic solvent is one or more of absolute ethyl alcohol, ethylene glycol ether and triethanolamine,
the catalyst is one or more of nickel nitrate, cobalt nitrate and ferric nitrate.
7. The method for preparing the quick-charging graphite composite material according to claim 6, wherein the ratio of the graphite to the oxidant solution to the sodium carbonate solution to the solid electrolyte is 100: (1-10): (1-10): (1-10).
8. The preparation method of the quick-filling graphite composite material as claimed in claim 7, wherein in the step S6, the proportion of the composite material A and the asphalt is 100 (5-15).
9. The preparation method of the quick-charging graphite composite material as claimed in claim 8, wherein in the step S7, the proportion of the composite material B and the catalyst is 100 (0.5-2) by mass ratio.
10. The preparation method of the quick-charging graphite composite material as claimed in claim 5, wherein the carbon source of the vapor deposition method is one of methane, ethane and ethylene, the temperature is 800 ℃, the time is 6h,
the particle injection method is carried out in an oxygen atmosphere, the gas flow is 1 sccm-10 sccm, and the gas pressure is 1 × 10sccm-4Pa～10×10-4Pa, injection temperature of 100 DEG CThe temperature is 500 ℃ below zero for 10min to 120 min.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115974114A (en) * | 2023-03-18 | 2023-04-18 | 河北坤天新能源股份有限公司 | Quick-filling graphite composite material and preparation method thereof |
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| CN1318872A (en) * | 2000-04-14 | 2001-10-24 | 北京市同治创新科技发展有限公司 | Lithium ion battery negative pole material and its preparation and use |
| CN107749472A (en) * | 2017-10-20 | 2018-03-02 | 乌兰察布市大盛石墨新材料股份有限公司 | A kind of high performance graphite composite negative pole material and preparation method thereof |
| CN113555539A (en) * | 2021-07-15 | 2021-10-26 | 洛阳月星新能源科技有限公司 | High-energy-density quick-charging graphite composite negative electrode material, preparation method thereof and lithium ion battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1318872A (en) * | 2000-04-14 | 2001-10-24 | 北京市同治创新科技发展有限公司 | Lithium ion battery negative pole material and its preparation and use |
| CN107749472A (en) * | 2017-10-20 | 2018-03-02 | 乌兰察布市大盛石墨新材料股份有限公司 | A kind of high performance graphite composite negative pole material and preparation method thereof |
| CN113555539A (en) * | 2021-07-15 | 2021-10-26 | 洛阳月星新能源科技有限公司 | High-energy-density quick-charging graphite composite negative electrode material, preparation method thereof and lithium ion battery |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115974114A (en) * | 2023-03-18 | 2023-04-18 | 河北坤天新能源股份有限公司 | Quick-filling graphite composite material and preparation method thereof |
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Inventor after: Jiao Kun Inventor after: Zheng Junxin Inventor after: She Qingxuan Inventor after: Liu Jian Inventor before: Jiao Kun Inventor before: Zheng Junxin Inventor before: Yu Qingxuan Inventor before: Liu Jian |