A resource recycling process for battery graphite negative electrode
By using ammonium persulfate solution leaching and nano-silicon-polyphenylene diamine composite material treatment, the problem of low resource recovery rate of graphite anodes in batteries was solved, achieving efficient impurity removal and high-performance graphite material recycling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI NANDU HUABO NEW MATERIAL TECH CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-06-12
AI Technical Summary
In existing technologies, the resource recovery rate of graphite anodes in batteries is low and impurities are not completely removed. Traditional processes cannot simultaneously protect the graphite structure and remove impurities, resulting in graphite materials failing to meet the needs of high-value-added applications.
Crude graphite was leached with ammonium persulfate solution, and impurity metal ions were removed by generating insoluble oxalate precipitate using oxalate ions. The pH was adjusted by Ba(OH)2 and NH4HCO3 was added to generate lithium carbonate precipitate with low solubility. Subsequently, it was compounded with nano-silicon-polyphenylene diamine composite material and calcined to form a high-performance graphite composite material.
This method achieves efficient removal of impurities, improves lithium recovery rate and graphite purity, and transforms graphite into high-performance carbon-based materials, thus solving the problem of high-value recycling of graphite anodes.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of battery resource recycling, specifically to a resource recycling process for battery graphite anodes. Background Technology
[0002] With the rapid development of the global new energy industry, the application of lithium batteries in consumer electronics, electric vehicles and energy storage has exploded. If lithium batteries are not efficiently recycled, it will not only cause a huge waste of resources such as lithium and graphite, but also cause environmental problems such as heavy metal pollution. At present, the resource recycling of graphite anodes in batteries faces three core challenges: incomplete removal of impurities, low lithium resource recovery rate and difficulty in regenerating graphite materials. The technical defects of traditional recycling processes have become a bottleneck restricting the development of the industry.
[0003] Traditional battery graphite anodes are produced by simple mechanical crushing and washing, which is difficult to effectively remove binders and metal foil impurities from the anode material. This not only affects the release of metal ions, but also leaves impurities on the graphite surface, making it impossible for the recycled graphite material to meet the requirements of high-value-added applications.
[0004] Conventional leaching processes often use common strong acids such as hydrochloric acid and sulfuric acid. Although these are inexpensive, hydrochloric acid lacks strong oxidizing properties and cannot efficiently decompose lithium-carbon intercalation compounds, resulting in a low lithium leaching rate. Furthermore, strong acids easily corrode carbon atoms at the edges of graphite, reducing the fixed carbon content and wasting graphite resources. In addition, traditional precipitation processes lack multi-stage impurity removal design, leaving calcium, magnesium, and other impurity ions in the leachate, which seriously affects the performance of subsequent materials.
[0005] Currently, the recycling of waste graphite anodes has long remained in the low-value-added field. The core reason is that traditional processes cannot simultaneously protect the graphite structure and remove impurities. Although traditional oxidation methods can strip graphite, strong oxidants will destroy the layered structure of graphite, leading to an increase in the interlayer spacing of the reduced material and a decrease in electrochemical capacity. The compatibility between recycled graphite without surface modification and electrolyte needs to be optimized, and the high-value recycling of graphite also needs to be further improved. To address this, a solution is proposed. Summary of the Invention
[0006] The purpose of this invention is to provide a resource recovery process for graphite anodes in batteries, which addresses the technical problem that the resource recovery rate of graphite anodes in batteries needs to be further improved in the existing technology.
[0007] The objective of this invention can be achieved through the following technical solution: a resource recycling process for graphite anodes in batteries, comprising the following steps:
[0008] S1. Cut the lithium battery negative electrode material into small pieces and perform pretreatment to obtain coarse graphite;
[0009] S2. Immerse the crude graphite in ammonium persulfate solution and leach at 80°C for 1 hour. Filter to obtain leachate and graphite.
[0010] S3. Add (NH4)2C2O4, Ba(OH)2 and H2SO4 to the leachate, filter, add NH4HCO3 to the filtrate, and filter under vacuum to obtain lithium carbonate;
[0011] Reaction principle:
[0012] C2O4 2- + Ca 2+ = CaC2O4
[0013] 2OH - + Mg 2+ = Mg(OH)2
[0014] 2Li + + HCO 3- = Li2CO3 + NH3↑ + 2H +
[0015] First, (NH4)2C2O4 is added, utilizing the oxalate ions to react with impurity metal ions such as calcium, magnesium, iron, copper, and manganese to form insoluble oxalate precipitates. Lithium ions, due to the high solubility of lithium oxalate, remain in the solution. Then, Ba(OH)2 is added to adjust the pH, causing the residual metal ions to precipitate as hydroxides. Next, H2SO4 is added, which reacts with Ba(OH)2 to form barium sulfate precipitate to remove barium ions and neutralize excess alkali. After filtration, NH4HCO3 is added, utilizing the bicarbonate ions to react with lithium ions to form lithium carbonate precipitate with low solubility, thereby achieving the separation and recovery of lithium.
[0016] S4. Oxidize the graphite and disperse it in deionized water to obtain an oxidized graphite dispersion. Disperse the p-phenylenediamine composite material in the oxidized graphite dispersion, sonicate for 30 minutes, and then freeze-dry to obtain regenerated graphite.
[0017] Reaction principle:
[0018] First, the interlayer structure of graphite is destroyed by oxidation reaction, and oxygen-containing functional groups are introduced and dispersed in deionized water to obtain graphite oxide dispersion. Then, p-phenylenediamine composite material is dispersed in graphite oxide dispersion, and the two are combined by means of hydrogen bonding, π-π conjugation and electrostatic attraction. After freeze drying, graphite oxide composite material with multiple properties is obtained.
[0019] S5. Calcine the recycled graphite at 600℃ under an argon atmosphere for 2 h to obtain a graphite composite material.
[0020] Further, in step S1, the pretreatment is as follows: the negative electrode material cut into small pieces is added to an organic solution and soaked for 10-20 minutes, filtered, the filter residue is added to an ethanol solution and ultrasonically dispersed for 20-30 minutes, filtered again, and the filter residue is placed in a drying oven and dried at 100-120°C to constant weight.
[0021] Furthermore, the organic solution is obtained by mixing dimethyl carbonate and N-methylpyrrolidone in a volume ratio of 1:2, and the ratio of the negative electrode material, the organic solution and ethanol is 1g:10mL:20mL.
[0022] Furthermore, in step S2, the ratio of crude graphite to ammonium persulfate solution is 3g:50mL, and the concentration of ammonium persulfate solution is 0.6-1mol / L.
[0023] Furthermore, in step S3, the ratio of the amount of leachate, (NH4)2C2O4, Ba(OH)2, H2SO4 and NH4HCO3 is 50mL:5g:1g:1mL:1.2g.
[0024] Furthermore, in step S4, the specific steps for oxidizing graphite are as follows: concentrated sulfuric acid, graphite and NaNO3 are uniformly mixed at 0°C, then KMnO4 is added in 3-5 portions, stirred for 1-2 hours, then the temperature is raised to 35°C and stirred continuously for 2 hours, then deionized water and H2O2 are slowly added dropwise, and stirring is continued for 10 minutes, and then filtered to obtain oxidized graphite.
[0025] Reaction principle:
[0026] Concentrated sulfuric acid was mixed with graphite at a low temperature of 0℃. The mixture was then inserted into the interlayer of graphite through protonation, causing it to expand. NaNO3 assisted KMnO4 to form a strong oxidation system. KMnO4 reacted with concentrated sulfuric acid to generate manganese heptaoxide, which gradually oxidized the carbon atoms at the edges and defects of the graphite layers to sp³ hybrid structures. Oxygen-containing functional groups such as epoxy groups and hydroxyl groups were introduced. After heating to 35℃, the oxidation reaction continued, prompting more functional groups to embed into the interlayer of graphite, weakening the interlayer van der Waals forces, and achieving the exfoliation of the layered structure. Subsequently, deionized water was added dropwise to dilute the system and the temperature was lowered. The added H2O2 reacted with the residual KMnO4. After filtration, graphite oxide was obtained.
[0027] Furthermore, the ratio of concentrated sulfuric acid, graphite, NaNO3, KMnO4, deionized water, and H2O2 is 48mL:1g:1g:6g:140mL:5mL.
[0028] Furthermore, in step S4, the preparation method of the p-phenylenediamine composite material is as follows: dispersing nano-silicon particles in Tris buffer solution, then adding p-phenylenediamine, ultrasonically dispersing for 30 min, stirring under normal pressure for 2 h, washing with deionized water 3-5 times, and then freeze-drying to obtain the p-phenylenediamine composite material.
[0029] Reaction principle:
[0030] By maintaining a weakly alkaline environment in the system using Tris buffer, and under ultrasonic dispersion, the hydroxyl groups on the surface of the nano-silicon particles bind to p-phenylenediamine molecules through hydrogen bonds. At the same time, the alkaline conditions cause the amino groups of p-phenylenediamine to lose protons and generate free radicals, initiating an oxidative coupling reaction. The mixture is further polymerized under normal pressure and stirring to form polyphenylenediamine polymer chains, which uniformly coat the surface of the nano-silicon. Unreacted p-phenylenediamine monomers and byproducts are removed by washing with deionized water. Freeze-drying and low-temperature sublimation prevent the agglomeration of nano-silicon and p-phenylenediamine polymers, and finally, a nano-silicon-polyphenylenediamine core-shell composite material is obtained.
[0031] Furthermore, the ratio of the nano-silicon particles, Tris buffer solution, and p-phenylenediamine is 1g:10mL:1g.
[0032] Furthermore, in step S4, the ratio of the p-phenylenediamine composite material to the graphite oxide dispersion is 1g:12mL.
[0033] The present invention has the following beneficial effects:
[0034] 1. The present invention involves cutting lithium battery anode material into small pieces and then sequentially soaking it in a mixed organic solution of dimethyl carbonate and N-methylpyrrolidone, followed by ultrasonic dispersion in ethanol and drying. This pretreatment process effectively removes impurities such as binders from the anode material, significantly improves the leaching rate of metal ions during subsequent leaching processes, thereby improving the recovery of lithium carbonate, removing impurities such as binders, and significantly improving the purity of graphite.
[0035] 2. This invention also employs ammonium persulfate solution to leach crude graphite at 80°C. Oxalate ions in (NH4)2C2O4 react with impurity metal ions such as calcium, magnesium, iron, copper, and manganese to form insoluble oxalate precipitates. Lithium ions, due to the high solubility of lithium oxalate, remain in the solution. The pH is adjusted using Ba(OH)2 to precipitate the residual metal ions as hydroxides. Then, H2SO4 is added to react with Ba(OH)2 to form barium sulfate precipitate, removing barium ions and neutralizing excess alkali. After filtration, NH4HCO3 is added to the filtrate, where bicarbonate ions react with lithium ions to form lithium carbonate precipitate with low solubility, thus achieving lithium resource recovery.
[0036] 3. The negative electrode graphite material of the present invention is subjected to an organic solution to remove impurities such as binders, and then leached with ammonium persulfate solution to extract metal ions, resulting in graphite with extremely high purity. The graphite is then oxidized to obtain graphite oxide, which is then compounded with nano-silicon-polyphenylene diamine composite material and calcined to finally obtain reduced graphite oxide composite material. This realizes the transformation from waste graphite negative electrode to high-performance carbon-based material. The whole process has high graphite utilization rate and thorough impurity removal, providing an efficient path for the high-value recycling of waste battery graphite negative electrodes. Detailed Implementation
[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.
[0038] In this application, dimethyl carbonate is selected from Jinan Xinchen Chemical Co., Ltd., with an effective ingredient content of 99% and CAS number 616-38-6;
[0039] In this application, N-methylpyrrolidone is selected from Shandong Xinyujia Chemical Co., Ltd., with CAS number 872-50-4, active ingredient content of 99.9%, and model number ZK1230;
[0040] In this application, the nano-silicon particles are selected from Shanghai Xiangtian Nanomaterials Co., Ltd., CAS No. 69012-64-2, with a silicon content ≥99.99% and a particle size of 200 mesh;
[0041] In this application, the Tris buffer solution is selected from Shanghai Chuangsai Technology Co., Ltd., with an active ingredient content of 97% and a product number of PM22362.
[0042] Example 1
[0043] This embodiment provides a resource recycling process for graphite anodes in batteries, including the following steps:
[0044] S1. Pretreatment of negative electrode material
[0045] Weigh out 100 mL of dimethyl carbonate and 200 mL of N-methylpyrrolidone, mix them thoroughly to obtain an organic solution;
[0046] Weigh out 10g of lithium battery negative electrode material, cut it into small pieces, add it to 100mL of organic solution and soak for 10min. Filter the solution, add the filter residue to 200mL of ethanol solution and ultrasonically disperse for 20min. Filter the solution again, put the filter residue into a drying oven and dry it at 100℃ to constant weight to obtain coarse graphite.
[0047] S2, Lithium Leaching
[0048] Weigh out 30g of crude graphite and immerse it in 500mL of 0.6mol / L ammonium persulfate solution. Immerse at 80℃ for 1h, filter, and obtain leachate and graphite.
[0049] S3, Preparation of lithium carbonate
[0050] Weigh out 500 mL of leachate, add 50 g of (NH4)2C2O4, 10 g of Ba(OH)2 and 10 mL of H2SO4, filter, add 12 g of NH4HCO3 to the filtrate, and filter under vacuum to obtain lithium carbonate.
[0051] S4, graphite oxide
[0052] Weigh out 480 mL of concentrated sulfuric acid, 10 g of graphite and 10 g of NaNO3 and mix them evenly at 0 °C. Then add 60 g of KMnO4 in three portions and stir for 1 h. Then heat to 35 °C and stir continuously for 2 h. Then slowly add 1400 mL of deionized water and 50 mL of H2O2 dropwise and continue stirring for 10 min. Filter to obtain graphite oxide.
[0053] S5. Preparation of recycled graphite
[0054] Weigh out 10g of nano-silicon particles and disperse them in 100mL of Tris buffer. Then add 10g of p-phenylenediamine, sonicate for 30 min, stir under normal pressure for 2 h, wash with deionized water 3 times, and freeze dry to obtain p-phenylenediamine composite material.
[0055] Weigh out 10g of graphite oxide and disperse it in 100mL of deionized water to obtain a graphite oxide dispersion. Disperse 10g of p-phenylenediamine composite material in 120mL of graphite oxide dispersion, sonicate for 30min, and then freeze-dry to obtain regenerated graphite.
[0056] S6. Preparation of graphite composite materials
[0057] Regenerated graphite was calcined at 600℃ under an argon atmosphere for 2 h to obtain a graphite composite material.
[0058] Example 2
[0059] This embodiment provides a resource recycling process for graphite anodes in batteries, including the following steps:
[0060] S1. Pretreatment of negative electrode material
[0061] Weigh out 100 mL of dimethyl carbonate and 200 mL of N-methylpyrrolidone, mix them thoroughly to obtain an organic solution;
[0062] Weigh out 10g of lithium battery negative electrode material, cut it into small pieces, add it to 100mL of organic solution and soak for 15min. Filter the solution, add the filter residue to 200mL of ethanol solution and ultrasonically disperse for 25min. Filter the solution again, put the filter residue into a drying oven and dry it at 110℃ to constant weight to obtain coarse graphite.
[0063] S2, Lithium Leaching
[0064] Weigh out 30g of crude graphite and immerse it in 500mL of 0.8mol / L ammonium persulfate solution. Immerse at 80℃ for 1h, filter, and obtain leachate and graphite.
[0065] S3, Preparation of lithium carbonate
[0066] Weigh out 500 mL of leachate, add 50 g of (NH4)2C2O4, 10 g of Ba(OH)2 and 10 mL of H2SO4, filter, add 12 g of NH4HCO3 to the filtrate, and filter under vacuum to obtain lithium carbonate.
[0067] S4, graphite oxide
[0068] Weigh out 480 mL of concentrated sulfuric acid, 10 g of graphite and 10 g of NaNO3 and mix them evenly at 0 °C. Then add 60 g of KMnO4 in 4 portions and stir for 1.5 h. Then raise the temperature to 35 °C and stir continuously for 2 h. Then slowly add 1400 mL of deionized water and 50 mL of H2O2 dropwise and continue stirring for 10 min. Filter to obtain graphite oxide.
[0069] S5. Preparation of recycled graphite
[0070] Weigh out 10g of nano-silicon particles and disperse them in 100mL of Tris buffer. Then add 10g of p-phenylenediamine, sonicate for 30 min, stir under normal pressure for 2 h, wash with deionized water 4 times, and freeze dry to obtain p-phenylenediamine composite material.
[0071] Weigh out 10g of graphite oxide and disperse it in 100mL of deionized water to obtain a graphite oxide dispersion. Disperse 10g of p-phenylenediamine composite material in 120mL of graphite oxide dispersion, sonicate for 30min, and then freeze-dry to obtain regenerated graphite.
[0072] S6. Preparation of graphite composite materials
[0073] Regenerated graphite was calcined at 600℃ under an argon atmosphere for 2 h to obtain a graphite composite material.
[0074] Example 3
[0075] This embodiment provides a resource recycling process for graphite anodes in batteries, including the following steps:
[0076] S1. Pretreatment of negative electrode material
[0077] Weigh out 100 mL of dimethyl carbonate and 200 mL of N-methylpyrrolidone, mix them thoroughly to obtain an organic solution;
[0078] Weigh out 10g of lithium battery negative electrode material, cut it into small pieces, add it to 100mL of organic solution and soak for 20min. Filter the solution, add the filter residue to 200mL of ethanol solution and ultrasonically disperse for 30min. Filter the solution again, put the filter residue into a drying oven and dry it at 120℃ to constant weight to obtain coarse graphite.
[0079] S2, Lithium Leaching
[0080] Weigh out 30g of crude graphite and immerse it in 500mL of 1mol / L ammonium persulfate solution. Immerse at 80℃ for 1h, filter, and obtain leachate and graphite.
[0081] S3, Preparation of lithium carbonate
[0082] Weigh out 500 mL of leachate, add 50 g of (NH4)2C2O4, 10 g of Ba(OH)2 and 10 mL of H2SO4, filter, add 12 g of NH4HCO3 to the filtrate, and filter under vacuum to obtain lithium carbonate.
[0083] S4, graphite oxide
[0084] Weigh out 480 mL of concentrated sulfuric acid, 10 g of graphite and 10 g of NaNO3 and mix them evenly at 0 °C. Then add 60 g of KMnO4 in 5 portions and stir for 2 h. Then heat to 35 °C and stir continuously for 2 h. Then slowly add 1400 mL of deionized water and 50 mL of H2O2 dropwise and continue stirring for 10 min. Filter to obtain graphite oxide.
[0085] S5. Preparation of recycled graphite
[0086] Weigh out 10g of nano-silicon particles and disperse them in 100mL of Tris buffer. Then add 10g of p-phenylenediamine, sonicate for 30 min, stir under normal pressure for 2 h, wash with deionized water 5 times, and freeze dry to obtain p-phenylenediamine composite material.
[0087] Weigh out 10g of graphite oxide and disperse it in 100mL of deionized water to obtain a graphite oxide dispersion. Disperse 10g of p-phenylenediamine composite material in 120mL of graphite oxide dispersion, sonicate for 30min, and then freeze-dry to obtain regenerated graphite.
[0088] S6. Preparation of graphite composite materials
[0089] Regenerated graphite was calcined at 600℃ under an argon atmosphere for 2 h to obtain a graphite composite material.
[0090] Comparative Example 1
[0091] The difference between this comparative example and Example 2 is that step S1 is omitted, and the coarse graphite in step S2 is directly replaced with lithium battery negative electrode material.
[0092] Comparative Example 2
[0093] The difference between this comparative example and Example 2 is that hydrochloric acid solution is used instead of ammonium persulfate solution in step S2.
[0094] Comparative Example 3
[0095] The difference between this comparative example and Example 2 is that sodium carbonate is used instead of NH4HCO3 in step S3.
[0096] Performance testing:
[0097] The fixed carbon content of graphite in Examples 1-3 and Comparative Examples 1-3 was determined according to the standard GB / T 3521-2023 "Methods for Chemical Analysis of Graphite";
[0098] The recovery rate of graphite in Examples 1-3 and Comparative Examples 1-3 was determined in accordance with the standard T / SPSTS 004-2018 "Technical Specification for Recycling of Lithium-ion Battery Anode Materials - Graphite".
[0099] The specific capacity and interlayer spacing d of the recycled graphite in Examples 1-3 and Comparative Examples 1-3 were determined according to the standard GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries". 002 ;
[0100] The leaching rate and recovery rate of lithium in Examples 1-3 and Comparative Examples 1-3 were determined in accordance with the standard TCIECCPA 037-2024 "Technical Specification for Wet Recycling of Waste Lithium Iron Phosphate Batteries - Preparation of Battery-Grade Lithium Carbonate".
[0101] The lithium carbonate content in Examples 1-3 and Comparative Examples 1-3 was determined according to standard YS / T 582-2023 "Battery Grade Lithium Carbonate". The specific test results are shown in Table 1-2 below:
[0102] Table 1 - Performance Test Data of Samples
[0103]
[0104] Table 2 - Performance Test Data of Samples
[0105]
[0106] Data Analysis:
[0107] Comparative analysis of the data in Table 1 above shows that in the resource recovery process of the graphite anode of the battery of the present invention, the lithium leaching rate is 99.52%, the lithium recovery rate is 96.48%, and the lithium carbonate content is 99.80%.
[0108] In Comparative Example 1, the removal of impurities such as binders through soaking in organic solvents and ultrasonic dispersion with ethanol resulted in residual organic matter on the graphite surface hindering the contact between lithium compounds and the leachate. Consequently, the lithium leaching rate, recovery rate, and lithium carbonate content decreased by 24.88%, 17.87%, and 11.0%, respectively, compared to Example 2.
[0109] In Comparative Example 2, hydrochloric acid lacked the strong oxidizing power of ammonium persulfate and could not decompose lithium-carbon intercalation compounds, resulting in a decrease in lithium leaching rate, recovery rate, and lithium carbonate content of 14.93%, 13.89%, and 4.99%, respectively, compared to Example 2.
[0110] The advantages of using NH4HCO3 precipitation in Comparative Example 3 in terms of selectivity and purity control resulted in a 7.96% decrease in lithium leaching rate, 8.91% decrease in recovery rate, and 7.99% decrease in lithium carbonate content compared to Example 2.
[0111] Comparative analysis of the data in Table 2 above shows that in the resource recovery process of the graphite anode of the battery of the present invention, the fixed carbon content of graphite is 99.97%, the graphite recovery rate is 99.98%, the initial discharge specific capacity is 354 (mA·h) / g, and the interlayer spacing d 002 It is 0.3356nm;
[0112] In Comparative Example 1, without soaking in organic solvents and ultrasonic dispersion with ethanol to remove binder and metal foil impurities, residual organic matter and metal debris remained on the graphite surface, resulting in lower fixed carbon content, lower graphite recovery rate, lower initial discharge specific capacity, and lower interlayer spacing d. 002 Compared with Example 2, the nm decreased by 14.0%, 15.0%, 14.1%, and 0.0302 nm, respectively;
[0113] Comparative Example 2: Hydrochloric acid lacks the strong oxidizing power of ammonium persulfate, and cannot efficiently decompose lithium-carbon intercalation compounds. Furthermore, under acidic conditions, H... + Corrosion of sp² hybridized carbon atoms at the graphite edges leads to the collapse of the graphite's layered structure, affecting the fixed carbon content, graphite recovery rate, initial discharge specific capacity, and interlayer spacing d. 002 Compared with Example 2, the nm decreased by 18.0%, 20.0%, 19.0%, and 0.0235 nm, respectively.
[0114] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A resource recycling process for graphite anodes in batteries, characterized in that, Includes the following steps: S1. Cut the lithium battery negative electrode material into small pieces and perform pretreatment to obtain coarse graphite; S2. Immerse the crude graphite in ammonium persulfate solution and leach at 80°C for 1 hour. Filter to obtain leachate and graphite. S3. Add (NH4)2C2O4, Ba(OH)2 and H2SO4 to the leachate, filter, add NH4HCO3 to the filtrate, and filter under vacuum to obtain lithium carbonate; S4. Oxidize the graphite and disperse it in deionized water to obtain an oxidized graphite dispersion. Disperse the p-phenylenediamine composite material in the oxidized graphite dispersion, sonicate for 30 minutes, and then freeze-dry to obtain regenerated graphite. S5. Calcine the recycled graphite at 600℃ under an argon atmosphere for 2 h to obtain a graphite composite material.
2. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S1, the pretreatment is as follows: the negative electrode material cut into small pieces is added to an organic solution and soaked for 10-20 minutes, filtered, the filter residue is added to an ethanol solution and ultrasonically dispersed for 20-30 minutes, filtered again, and the filter residue is placed in a drying oven and dried at 100-120℃ to constant weight.
3. The resource recycling process for a battery graphite anode according to claim 2, characterized in that, The organic solution is obtained by mixing dimethyl carbonate and N-methylpyrrolidone in a volume ratio of 1:2, and the ratio of the negative electrode material, organic solution and ethanol is 1g:10mL:20mL.
4. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S2, the ratio of crude graphite to ammonium persulfate solution is 3g:50mL, and the concentration of ammonium persulfate solution is 0.6-1mol / L.
5. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S3, the ratio of the amount of leachate, (NH4)2C2O4, Ba(OH)2, H2SO4 and NH4HCO3 is 50mL:5g:1g:1mL:1.2g.
6. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S4, the specific steps for oxidizing graphite are as follows: concentrated sulfuric acid, graphite and NaNO3 are uniformly mixed at 0°C, then KMnO4 is added in 3-5 portions and stirred for 1-2 hours. Then the temperature is raised to 35°C and stirred continuously for 2 hours. Subsequently, deionized water and H2O2 are slowly added dropwise and stirred for 10 minutes. The mixture is then filtered to obtain oxidized graphite.
7. The resource recycling process for a graphite anode in a battery according to claim 6, characterized in that, The ratio of concentrated sulfuric acid, graphite, NaNO3, KMnO4, deionized water, and H2O2 used is 48mL:1g:1g:6g:140mL:5mL.
8. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S4, the preparation method of the p-phenylenediamine composite material is as follows: disperse nano-silicon particles in Tris buffer, then add p-phenylenediamine, ultrasonically disperse for 30 min, stir under normal pressure for 2 h, wash with deionized water 3-5 times, and freeze dry to obtain the p-phenylenediamine composite material.
9. The resource recycling process for a battery graphite anode according to claim 8, characterized in that, The ratio of the nano-silicon particles, Tris buffer solution, and p-phenylenediamine is 1g:10mL:1g.
10. The resource recycling process for a graphite anode in a battery according to claim 1, characterized in that, In step S4, the ratio of the p-phenylenediamine composite material to the graphite oxide dispersion is 1g:12mL.