Method for preparing and recycling graphite carbon-loaded nonmetal-doped low-platinum medium-entropy intermetallic compound by using waste ternary lithium ion battery

Abstract

The invention relates to the technical field of lithium air battery catalysts, in particular to a method for preparing and recycling a graphite carbon loaded nonmetal doped low-platinum medium-entropy intermetallic compound by utilizing a waste ternary lithium ion battery, which comprises the following steps: firstly, disassembling the waste battery to extract and recycle a graphite carbon matrix and Ni, Co and Mn precursor impurity removal liquid; the preparation method comprises the following steps: recovering a graphite carbon matrix, then introducing a noble metal X, loading X (NiCoMn) 3 low-platinum medium-entropy intermetallic compound alloy particles on the surface of the recovered graphite carbon matrix through Joule heating, then etching the surface metal NiCoMn through a sulfuric acid etching dealloying method to obtain a defect-state X (NiCoMn) 3-x (at) RC material, and finally preparing the catalyst through a Joule heating technology. The invention provides a method for preparing a high-performance bifunctional catalyst for a lithium-oxygen battery, which integrates synergistic utilization and high-valued conversion of waste batteries. The obtained catalyst can show excellent electrochemical performance when being used for a positive electrode material of a lithium-air battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-air battery catalyst technology, specifically to a method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries. Background Technology

[0002] With the continuous expansion of the lithium-ion battery market, the number of retired ternary lithium-ion batteries is growing exponentially. Currently, the traditional recycling of spent ternary lithium-ion batteries mainly focuses on recovering high-value cathode transition metals (nickel, cobalt, and manganese). However, considering the good graphitization and conductivity of the carbon-based anode materials in spent batteries, the separate recovery of anode carbon and high-value cathode transition metals for use in the catalyst field is expected to become one of the key directions for the high-value utilization of spent batteries.

[0003] The proton lithium-oxygen (Li-O2) battery has a capacity of 3500 Wh / kg. -1 While achieving ultra-high theoretical energy density, the slow kinetics of the oxygen reduction / oxygen evolution reaction and the strong insulating properties of the discharge product Li2O2 lead to significant overpotential and short cycle life, necessitating the development of highly efficient bifunctional catalysts to overcome these bottlenecks. Summary of the Invention

[0004] This invention provides a method for preparing recycled graphite-carbon-supported non-metallic doped low-platinum medium-entropy intermetallic compounds from spent ternary lithium-ion batteries. Addressing the bottlenecks of existing spent ternary lithium-ion battery recycling technologies, such as complex processes, high energy consumption, and poor electrochemical performance of the recycled products after conversion into catalytic materials, this invention aims to provide a method that combines the co-utilization and high-value conversion of spent batteries for the preparation of high-performance bifunctional catalysts for lithium-oxygen batteries. The resulting catalysts exhibit excellent electrochemical performance when used as cathode materials in lithium-air batteries. This invention features a simple technical path, low recycling costs, and achieves the conversion of spent battery resources into high-performance catalysts while ensuring high recovery rates and high purity of transition metals.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing recycled graphite carbon-supported nonmetallic doped low-platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries includes: firstly, disassembling the spent batteries to extract and recycle the graphite carbon matrix and Ni, Co, and Mn precursor impurity removal solution; then introducing a noble metal X, and loading X(NiCoMn)3 low-platinum intermediate-entropy intermetallic compound alloy particles onto the surface of the recycled graphite carbon matrix by Joule heating; subsequently, etching away the surface metal NiCoMn using a sulfuric acid etching dealloying method to obtain defective states X(NiCoMn). 3-x@RC material, and finally prepared YX(NiCoMn) by non-metallic atom intercalation doping through Joule heating technique. 3-x @RC catalyst.

[0006] Preferably, the method includes the following specific steps: (1) The waste ternary lithium-ion battery after complete discharge is pretreated. The obtained negative electrode graphite is immersed in NMP and sonicated for 18-24h. The graphite after sonication is centrifuged. Then, acid leaching is performed with 1MHCL for 3-6h to remove excess impurities. Then, it is washed with deionized water and centrifuged twice. The obtained black precipitate is dried to finally obtain the recycled graphite carbon matrix. (2) The waste ternary lithium-ion batteries were short-circuited, discharged, and disassembled. After soaking in N,N-dimethylpyrrolidone (NMP) and sonicating for 18-24 hours to dissolve and peel off the PVDF binder, a leachate containing Li, Mn, Ni, and Co was obtained. The leachate precipitate was dried in a drying oven at 80-100°C for 12-16 hours. Li was removed using oxalic acid and nitric acid solutions as leaching agents. + The impurity removal solution is obtained by removing carbon black and insoluble impurities; (3) The recycled graphite carbon matrix from step (1), the noble metal X ion precursor solution, and the impurity removal liquid from step (2) are magnetically stirred and mixed evenly. After centrifugation, the mixture is evaporated to dryness to obtain the recycled carbon material with surface metal ions. The material is then heated by Joule heating at 1000℃~2500℃ under a nitrogen protective atmosphere to form recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticle material. (4) Add the recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticles obtained in step (3) to 40 ml of H2SO4 solution, etch for 10-14 h, then centrifuge and dry to obtain X(NiCoMn). 3-x @RC materials; (5) Obtain X(NiCoMn) from step (4) 3-x @RC material and non-metallic Y precursor raw materials are mixed evenly, and then calcined by one-step Joule heating at 1000℃~2500℃ for 5-15s to finally obtain YX(NiCoMn). 3-x @RC materials.

[0007] Preferably, in steps (1) and (2), the NMP solution concentration is 1 ~ 1.5 g / mL, and in step (2), the concentrations of oxalic acid and nitric acid solutions are 1 ~ 5 mol / mL, respectively.

[0008] Preferably, in step (3), the molar ratio of Ni, Co, and Mn in the impurity removal solution is 1:1:1; and the molar ratio of the sum of Ni, Co, and Mn to the noble metal X is 3:1.

[0009] Preferably, in steps (3) and (5), the Joule heating rate is 200~800℃ / s, the holding time is 2~5s, and the cooling rate is 200~800℃ / s.

[0010] Preferably, in step (4), the concentration of the sulfuric acid solution is 1~5 mol / mL.

[0011] Preferably, in step (5), the non-metallic atom Y is S, Se, or P; its precursor raw materials are thiourea, selenium powder, and sodium phosphate, respectively; YX(NiCoMn) 3-x The average diameter of the RC alloy nanoparticles is 5-40 nm, X(NiCoMn). 3-x The element accounts for 5%-30% of the total mass.

[0012] An application of a method for preparing recycled graphite carbon-supported nonmetallic doped low platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries, wherein the prepared YX(NiCoMn) 3-x @RC material is used as a cathode material in lithium-air batteries.

[0013] Preferably, the prepared YX(NiCoMn) 3-x The method for using RC materials as cathode materials in lithium-air batteries is as follows: Recycled graphite carbon-supported non-metallic doped low-platinum medium-entropy intermetallic compound material YX(NiCoMn) is prepared from spent ternary lithium-ion batteries. 3-x @RC powder, conductive carbon black, and polytetrafluoroethylene binder are uniformly dispersed in NMP solution at a mass ratio of 8:1:1. After stirring for 24 hours, a mixed slurry of suitable viscosity is formed. The slurry is then uniformly coated onto the surface of a stainless steel mesh current collector and dried under vacuum at 80°C to obtain an electrode sheet loaded with positive electrode material. The active material loading of each positive electrode sheet is 2.0–3.0 mg / cm³. 2 Assemble a 2032 coin cell lithium-air battery: Use the obtained electrode as the positive electrode, lithium metal as the negative electrode, Celgard 3500 as the separator, and a solution of lithium perchlorate dissolved in tetraethylene glycol dimethyl ether as the electrolyte with a concentration of 1-2 mol / L.

[0014] The beneficial effects of this invention, a method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries, are as follows: 1. By forming a medium-entropy intermetallic compound with low precious metal content through Joule heating, the amount of precious metal used can be reduced, saving costs. The introduced medium-entropy M component can release the catalytic activity of the precious metal, combining the catalytic advantages of each component to improve its utilization efficiency. Furthermore, it can regulate the electronic structure of the catalytic center, providing richer active centers and better reaction pathways for electrocatalytic reactions. Simultaneously, the entropy stabilization effect of the medium-entropy system and the synergistic effect of the formation of the ordered structure of the intermetallic compound effectively optimize the adsorption-desorption behavior of oxygen-containing intermediates and the interfacial charge transfer process. The Ni / Co / Mn multi-component center further lowers the reaction barrier through synergistic electron transfer, and the synergistic effect of both significantly improves the bifunctional catalytic kinetics of ORR / OER in lithium-oxygen batteries.

[0015] 2. In medium-entropy intermetallic compounds with low noble metal content, nickel-cobalt-manganese dealloying on the surface of X(NiCoMn)3 leads to the formation of metal vacancies on the alloy surface. This creates a high density of unsaturated coordinated noble metal active centers, lowering the reaction energy barrier, disrupting the original electronic balance, inducing a shift in the d-band centroid of the noble metal, and causing charge rearrangement at the active centers. This strengthens the orbital hybridization between the noble metal and the intermediates. Simultaneously, the built-in electric field formed by the metal vacancies accelerates charge transfer, further enhancing catalytic activity. The surface metal vacancies introduced by dealloying provide more exposed active sites for the ORR / OER process, and the lattice distortion caused by the local structure due to metal vacancies can also optimize the adsorption structure of oxygen-containing intermediates.

[0016] 3. Further embedding of non-precious metal atoms into surface vacancy interstices can enhance structural stability, fill surface defects, reduce the risk of structural collapse caused by electrolyte erosion, and extend cycle life. This forms a dual-active-center system. The noble metal X site activates O2 molecules with its high intrinsic activity, while the non-precious metal Y atom modulates the adsorption energy barrier of oxygen-containing intermediates to meet the dual-reaction requirements. The synergistic regulation of X and Y can overcome the limitations of a single active site in simultaneously addressing dual-reaction kinetics. Furthermore, the embedding of Y further induces lattice distortion, re-exciting charge rearrangement and d-center shift in the X active center, while simultaneously triggering dp orbital interactions. Orbital hybridization can also modulate electron cloud density, avoiding desorption trapping due to excessively strong adsorption of intermediates or insufficient activation due to excessively weak adsorption. On the other hand, the electronegativity difference between non-metal Y and noble metal X forms a local micro-electric field, accelerating interfacial charge transfer and further improving ORR / OER kinetic efficiency. Non-precious metals have the advantages of high reserves and low cost; embedding them into metal vacancies can improve catalytic performance without increasing the noble metal loading.

[0017] 4. The materials of this invention are abundant, inexpensive, and reduce the dependence of catalysts on precious metals, which meets the development needs of resource recycling and low-cost catalysis, and is suitable for large-scale production. Attached Figure Description

[0018] Figure 1 Scanning electron microscope image of a nonmetal-doped low-platinum intermediate-entropy intermetallic compound catalyst supported on graphite carbon for recovery. Figure 2 X-ray diffraction pattern for recovering graphite carbon-supported nonmetal-doped low-platinum intermetallic compound catalyst; Figure 3 Transmission electron microscopy image of a nonmetal-doped low-platinum intermediate-entropy intermetallic compound catalyst supported on graphite carbon for recovery. Figure 4 A high-angle annular dark-field scanning transmission electron microscope image for the recovery of graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compound catalysts. Figure 5 The initial charge-discharge curves of a medium-entropy intermetallic compound catalyst with low noble metal content supported on carbon for recovery. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0020] Example 1: A method for preparing recycled graphite carbon-supported nonmetallic doped low-platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries includes: firstly, disassembling the spent batteries to extract and recycle the graphite carbon matrix and Ni, Co, and Mn precursor impurity removal solution; then introducing a noble metal X, and loading X(NiCoMn)3 low-platinum intermediate-entropy intermetallic compound alloy particles onto the surface of the recycled graphite carbon matrix by Joule heating; subsequently, etching away the surface metal NiCoMn using a sulfuric acid etching dealloying method to obtain defective states X(NiCoMn). 3-x @RC material, and finally prepared YX(NiCoMn) by non-metallic atom intercalation doping through Joule heating technique. 3-x @RC catalyst.

[0021] Example 2: Based on Example 1, this example discloses that the method includes the following specific steps: (1) The waste ternary lithium-ion battery after complete discharge is pretreated. The obtained negative electrode graphite is immersed in NMP and sonicated for 18-24h. The graphite after sonication is centrifuged. Then, acid leaching is performed with 1MHCL for 3-6h to remove excess impurities. Then, it is washed with deionized water and centrifuged twice. The obtained black precipitate is dried to finally obtain the recycled graphite carbon matrix. (2) The waste ternary lithium-ion batteries were short-circuited, discharged, and disassembled. After soaking in N,N-dimethylpyrrolidone (NMP) and sonicating for 18-24 hours to dissolve and peel off the PVDF binder, a leachate containing Li, Mn, Ni, and Co was obtained. The leachate precipitate was dried in a drying oven at 80-100°C for 12-16 hours. Li was removed using oxalic acid and nitric acid solutions as leaching agents. + The impurity removal solution is obtained by removing carbon black and insoluble impurities; (3) The recycled graphite carbon matrix from step (1), the noble metal X ion precursor solution, and the impurity removal liquid from step (2) are magnetically stirred and mixed evenly. After centrifugation, the mixture is evaporated to dryness to obtain the recycled carbon material with surface metal ions. The material is then heated by Joule heating at 1000℃~2500℃ under a nitrogen protective atmosphere to form recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticle material. (4) Add the recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticles obtained in step (3) to 40 ml of H2SO4 solution, etch for 10-14 h, then centrifuge and dry to obtain X(NiCoMn). 3-x @RC materials; (5) Obtain X(NiCoMn) from step (4) 3-x @RC material and non-metallic Y precursor raw materials are mixed evenly, and then calcined by one-step Joule heating at 1000℃~2500℃ for 5-15s to finally obtain YX(NiCoMn). 3-x @RC materials.

[0022] Example 3: Based on Example 2, this example discloses: In steps (1) and (2), the NMP solution concentration is 1 ~ 1.5 g / mL, and in step (2), the concentrations of oxalic acid and nitric acid solutions are 1 ~ 5 mol / mL, respectively.

[0023] In step (3), the molar ratio of Ni, Co, and Mn in the impurity removal solution is 1:1:1; the molar ratio of the sum of Ni, Co, and Mn to the noble metal X is 3:1.

[0024] In steps (3) and (5), the Joule heating rate is 200~800℃ / s, the holding time is 2~5s, and the cooling rate is 200~800℃ / s.

[0025] In step (4), the concentration of sulfuric acid solution is 1~5 mol / mL.

[0026] In step (5), the non-metallic atom Y is S, Se, or P; its precursor raw materials are thiourea, selenium powder, and sodium phosphate, respectively; YX(NiCoMn) 3-x The average diameter of the RC alloy nanoparticles is 5-40 nm, X(NiCoMn). 3-x The element accounts for 5%-30% of the total mass.

[0027] Example 4: Based on the above embodiments, this embodiment discloses the application of a method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries, wherein the prepared YX(NiCoMn) 3-x @RC material is used as a cathode material in lithium-air batteries.

[0028] Example 5: Based on Example 4, this example discloses: the prepared YX(NiCoMn) 3-x The method for using RC materials as cathode materials in lithium-air batteries is as follows: Recycled graphite carbon-supported non-metallic doped low-platinum medium-entropy intermetallic compound material YX(NiCoMn) is prepared from spent ternary lithium-ion batteries. 3-x @RC powder, conductive carbon black, and polytetrafluoroethylene binder are uniformly dispersed in NMP solution at a mass ratio of 8:1:1. After stirring for 24 hours, a mixed slurry of suitable viscosity is formed. The slurry is then uniformly coated onto the surface of a stainless steel mesh current collector and dried under vacuum at 80°C to obtain an electrode sheet loaded with positive electrode material. The active material loading of each positive electrode sheet is 2.0–3.0 mg / cm³. 2 Assemble a 2032 coin cell lithium-air battery: Use the obtained electrode as the positive electrode, lithium metal as the negative electrode, Celgard 3500 as the separator, and a solution of lithium perchlorate dissolved in tetraethylene glycol dimethyl ether as the electrolyte with a concentration of 1-2 mol / L.

[0029] like Figure 1-5 As shown, recycled carbon from waste lithium-ion battery anodes is used as the matrix, and non-metallic doped low-platinum medium-entropy intermetallic compound YX(NiCoMn) is loaded onto it. 3-x @RC, used as a cathode catalyst in lithium-oxygen batteries, significantly weakens the polarization reaction and effectively reduces the overpotential during charge and discharge processes, at 200 mA g. -1At current, an ultra-low total voltage gap of 0.35 V was achieved, during which the discharge and charge polarizations were reduced to only 0.32 V and 0.03 V, respectively, with an energy efficiency of up to 88.3%, demonstrating excellent ORR / OER bifunctional catalytic activity.

Claims

1. A method for preparing recycled graphite carbon-supported nonmetallic doped low platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries. Its characteristics include: First, disassemble the waste batteries to extract and recycle the graphite carbon matrix and Ni, Co, and Mn precursors in the impurity removal solution; Subsequently, noble metal X is introduced to load X(NiCoMn)3 low-platinum intermetallic compound alloy particles on the surface of the recycled graphite carbon matrix by Joule heating, and then the surface metal NiCoMn is etched away by a sulfuric acid etching and de-alloying method to obtain a defect state X(NiCoMn) 3-x @RC material, and finally a Y-X(NiCoMn) is prepared by a non-metal atom embedding and doping method through a Joule heating technique 3-x @RC catalyst.

2. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 1, characterized in that, The method includes the following specific steps: (1) The waste ternary lithium-ion battery after complete discharge is pretreated. The obtained negative electrode graphite is immersed in NMP and sonicated for 18-24h. The graphite after sonication is centrifuged. Then, acid leaching is performed with 1MHCL for 3-6h to remove excess impurities. Then, it is washed with deionized water and centrifuged twice. The obtained black precipitate is dried to finally obtain the recycled graphite carbon matrix. (2) The waste ternary lithium ion battery is short-circuited and discharged, disassembled, soaked in N-N, dimethylpyrrolidone for 18-24h, and the PVDF binder is dissolved and peeled off, so as to obtain a leaching solution containing Li, Mn, Ni and Co, the precipitate of the leaching solution is dried in a drying box at a temperature of 80-100°C for 12-16h, and Li is removed by using oxalic acid and nitric acid solution as a leaching agent + , carbon black and insoluble impurities to obtain a decontamination solution; (3) The recycled graphite carbon matrix from step (1), the noble metal X ion precursor solution, and the impurity removal liquid from step (2) are magnetically stirred and mixed evenly. After centrifugation, the mixture is evaporated to dryness to obtain the recycled carbon material with surface metal ions. The material is then heated by Joule heating at 1000℃~2500℃ under a nitrogen protective atmosphere to form recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticle material. (4) Add the recycled carbon matrix supported X(NiCoMn)3 alloy nanoparticles obtained in step (3) to 40 ml of H2SO4 solution, etch for 10-14 h, then centrifuge and dry to obtain X(NiCoMn). 3-x @RC materials; (5) Obtain X(NiCoMn) from step (4) 3-x @RC material and non-metallic Y precursor raw materials are mixed evenly, and then calcined by one-step Joule heating at 1000℃~2500℃ for 5-15s to finally obtain YX(NiCoMn). 3-x @RC materials.

3. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 2, characterized in that, In steps (1) and (2), the NMP solution concentration is 1~1.5 g / mL, and in step (2), the concentrations of oxalic acid and nitric acid solutions are 1~5 mol / mL, respectively.

4. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 2, characterized in that... In step (3), the molar ratio of Ni, Co, and Mn in the impurity removal solution is 1:1:1; the molar ratio of the sum of Ni, Co, and Mn to the noble metal X is 3:

1.

5. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 2, characterized in that, In steps (3) and (5), the Joule heating rate is 200~800℃ / s, the holding time is 2~5s, and the cooling rate is 200~800℃ / s.

6. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 2, characterized in that, In step (4), the concentration of sulfuric acid solution is 1~5 mol / mL.

7. The method for preparing recycled graphite carbon-supported non-metallic doped low-platinum intermediate-entropy intermetallic compounds using waste ternary lithium-ion batteries as described in claim 2, characterized in that, In step (5), the non-metallic atom Y is S, Se, or P; its precursor raw materials are thiourea, selenium powder, and sodium phosphate, respectively; YX(NiCoMn) 3-x The average diameter of the RC alloy nanoparticles is 5-40 nm, X(NiCoMn). 3-x The element accounts for 5%-30% of the total mass.

8. An application of a method for preparing recycled graphite carbon-supported nonmetallic doped low platinum intermediate-entropy intermetallic compounds using spent ternary lithium-ion batteries, wherein the YX(NiCoMn) prepared as described in claim 1 or 2 is used. 3-x @RC material is used as a cathode material in lithium-air batteries.

9. The application as described in claim 8, wherein the prepared YX(NiCoMn) 3-x The method for using RC materials as cathode materials in lithium-air batteries is as follows: Recycled graphite carbon-supported non-metallic doped low-platinum medium-entropy intermetallic compound material YX(NiCoMn) is prepared from spent ternary lithium-ion batteries. 3-x @RC powder, conductive carbon black, and polytetrafluoroethylene binder are uniformly dispersed in NMP solution at a mass ratio of 8:1:

1. After stirring for 24 hours, a slurry with suitable viscosity is formed. The slurry is then uniformly coated onto the surface of a stainless steel mesh current collector and dried under vacuum at 80°C to obtain an electrode sheet loaded with positive electrode material. The active material loading of each positive electrode sheet is 2.0–3.0 mg / cm³. 2 Assemble a 2032 coin cell lithium-air battery: Use the obtained electrode as the positive electrode, lithium metal as the negative electrode, Celgard 3500 as the separator, and a solution of lithium perchlorate dissolved in tetraethylene glycol dimethyl ether as the electrolyte with a concentration of 1-2 mol / L.

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