Preparation method and application of nickel-copper bimetallic phthalocyanine-based organic framework magnesium ion battery positive electrode material

Abstract

The application belongs to the field of battery materials, and particularly relates to a preparation method and application of a nickel-copper bimetal phthalocyanine-based organic framework magnesium ion battery positive electrode material. The prepared positive electrode material adopts 2D CuPc-Ni MOF as a positive electrode active material, CuPc-Ni MOF is deposited in situ on the surface of a foamed nickel, is coated on the outer layer of the foamed nickel matrix, and presents a stacked sub-micron spherical morphology. The solvent-thermal, rotary evaporation, extraction and chromatographic column separation method and the electrodeposition method are used to prepare the conductive CuPc-Ni MOF@NF positive electrode material, the material does not need an additional current collector and an additive, can be directly used as a positive electrode sheet, the MOFs positive electrode material with a main carbon skeleton is selected, the coulombic force with Mg 2+ is effectively reduced, the porous structure is beneficial to the fast transmission of Mg 2+ , the formation of the conjugate structure greatly improves the stability of the material, and the positive electrode material exhibits excellent performance in the performance test of the magnesium ion battery.

Description

Technical Field

[0001] This invention belongs to the field of battery materials, specifically relating to a method for preparing and applying a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material. Background Technology

[0002] Energy and environmental issues are two major challenges facing the sustainable development of human society. Currently, non-renewable fossil fuels still account for 85% of global energy consumption annually, while the Earth's crustal reserves of fossil fuels are finite. Furthermore, the uneven distribution of global fossil fuel production means that future energy competition will inevitably lead to more intense geopolitical conflicts and could even trigger global instability. The unrestrained exploitation and use of fossil fuels will generate large amounts of harmful substances such as waste gas and particulate matter. This will inevitably lead to a series of environmental problems, including environmental pollution, ecological imbalance, and the greenhouse effect, which will seriously threaten the human living environment. Therefore, exploring new energy sources and developing an efficient and renewable energy system is an inevitable trend in current social development.

[0003] With the ever-increasing demand for energy storage devices, lithium-ion batteries (LIBs) have become a popular choice for various electronic devices such as digital cameras and mobile phones due to their high capacity and stable cycle life. However, resource constraints and operational safety issues of LIBs have sparked great interest in other novel energy storage systems, such as magnesium, aluminum, and calcium batteries. Rechargeable magnesium batteries (RMBs) are considered one of the most promising alternatives due to their favorable properties, high natural abundance, atmospheric stability, low cost, and eco-friendliness. Furthermore, Mg can achieve a capacity of 2205 mAh / g. -1 High theoretical specific capacity and 3833mAh cm -3 Magnesium-ion batteries boast high volumetric capacity comparable to lithium metal batteries. The abundance of magnesium in the Earth's crust (~2.0%) far exceeds that of lithium (~0.0065%), thus reducing the production cost of magnesium-based batteries. Most importantly, Mg metal electrodes avoid dendrite formation during cycling, unlike Li and Na metal electrodes. Since dendrite formation prevents the commercialization of lithium metal anodes, this makes Mg batteries even more attractive for practical applications. In this sense, magnesium-ion batteries are highly promising for next-generation energy storage systems.

[0004] Compared to inorganic cathode materials, organic cathode materials are abundant, low-cost, sustainable, and environmentally friendly. Furthermore, most organic cathodes possess more flexible Mg content compared to inorganic cathodes. 2+ Transfer pathways and lower intermolecular forces hold promise for improving reaction kinetics and cycle stability in magnesium-ion batteries. However, most traditional organic compounds exhibit high solubility and low electronic / ionic conductivity in organic electrolytes, leading to severe polarization and capacity decay issues. Furthermore, organic cathodes containing magnesium... 2+The dissociation / desolvation process is difficult to control, and there is a lack of bulk diffusion control strategies. These problems mean that organic cathode magnesium storage has not yet demonstrated any significant advantages in reaction kinetics.

[0005] Metal-organic frameworks (MOFs) are a class of porous materials based on the highly ordered connection of metal ions / clusters and organic ligands. Due to their structural diversity, porosity, tailorability, and ultra-high specific surface area, MOFs have been widely used in gas adsorption, storage and separation, electrode materials, and catalysis in recent years. MOFs possess cross-linked polymer structures, are stable, and insoluble in organic electrolytes, making them suitable for battery applications. Furthermore, their highly ordered porous structure and large surface area provide abundant electrode-electrolyte interfaces, facilitating the exploration of magnesium ion desolvation mechanisms and the development of bulk diffusion control strategies, and fully adapting to volume changes during electrochemical processes. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material and its application. The metal-organic framework is abundant and environmentally friendly, and has weak interaction with magnesium ions. The resulting cathode material has good stability and conductivity, which can improve the cycle stability and rate performance of the battery.

[0007] The technical solution adopted is as follows:

[0008] A method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material, wherein the nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material uses 2D CuPc-Ni MOF as the electrode active material, wherein the molecular formula of CuPc-NiMOF is [Ni2Cu(C 32 H 16 N 16 )] n CuPc-Ni MOF molecules are deposited in situ on the surface of nickel foam and coated on the outer layer of the nickel foam substrate, exhibiting a stacked submicron-sized spherical morphology.

[0009] Its preparation method includes the following steps:

[0010] (1) Add the raw material 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine to the flask, disperse anhydrous copper chloride in n-hexanol solvent, and then add DBU;

[0011] The solution is then sealed and reacted after being pumped with an inert gas and heated with stirring.

[0012] After the reaction system was cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure. The crude product was redissolved in CH2Cl2 / AcOH and then extracted with water. After drying, filtration, rotary evaporation, and separation by silica gel column chromatography, a blue-green solid product was finally obtained.

[0013] (2) The blue-green solid product obtained in step (1) was added to a round-bottom flask and dispersed in concentrated sulfuric acid and deionized water. The mixture was heated and stirred. After the reaction system cooled to room temperature, the mixture was poured into a beaker containing ice water. A large amount of blue-green precipitate appeared immediately. The precipitate was separated from the mother liquor by centrifugation and then washed with deionized water, 10% NaOH solution, deionized water and ethanol in sequence. The mixture was then dried under vacuum to finally obtain the black product CuPc-NH2.

[0014] (3) Electrodeposition was performed in a small dual-electrode device using nickel foam as the working electrode and nickel foil as the counter electrode. The black product CuPc-NH2 obtained in step (2) was added to a solution of DMF and 1-butyl-3-methylimidazolium chloride as the electrolyte for electrodeposition. During the electrodeposition process, the dark red solution gradually turned colorless, and black MOF particles were grown on the nickel foam electrode to obtain CuPc-Ni MOF@NF positive electrode sheet.

[0015] (4) The CuPc-Ni MOF@NF positive electrode sheet from step (3) is washed with deionized water and anhydrous ethanol and then dried under vacuum to obtain the final product.

[0016] Preferably, in step (1), the molar ratio of 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine and anhydrous copper chloride is 1:1; and the volume ratio of n-hexanol and DBU is 6:1.

[0017] Preferably, in step (1), the solution is sealed and reacted after being replaced by an oil pump and an inert gas, the heating temperature is 120-160°C, and the stirring reaction time is 24-72 hours.

[0018] Preferably, in step (1), the silica gel column is used for separation, and the eluent is CH2Cl2 / MeOH.

[0019] Preferably, in step (1), the volume ratio of CH2Cl2 (dichloromethane) to AcOH (acetic acid) in the crude product solvent is 2 to 5:1, and the volume ratio of CH2Cl2 to water in the extractant is 1:1; the volume ratio of CH2Cl2 to MeOH (methanol) in the eluent is 30 to 50:1.

[0020] Preferably, in step (2), the volume ratio of concentrated sulfuric acid to deionized water is 10:1; the temperature of the mixed solution is heated to 100-120°C, and the reaction time is 1-4 hours.

[0021] Preferably, in the electrodeposition process of step (3), DMF is used as a solvent and 1-butyl-3-methylimidazolium chloride is used as an electrolyte with a concentration of 0.1M.

[0022] Preferably, in step (3), the concentration of CuPc-NH2 added during electrodeposition is 7.2 × 10⁻⁶. -4 M, reaction voltage is 1.1V, reaction time is 8 hours.

[0023] An application of a conductive nickel-copper bimetallic phthalocyanine metal-organic framework (MOF@NF) cathode material in the preparation of magnesium-ion batteries is described. In an anhydrous and oxygen-free glove box, a CuPc-Ni MOF@NF cathode sheet was assembled with activated carbon cloth, glass fiber, a stainless steel button cell assembly, and a magnesium bis(trifluoromethanesulfonyl)imide electrolyte dissolved in ethylene glycol dimethyl ether to obtain a magnesium-ion battery.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention utilizes 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine as a raw material to prepare a conductive CuPc-Ni MOF@NF cathode material via solvothermal, rotary evaporation, extraction, column chromatography, and electrodeposition. This material can be directly used as the cathode without the need for external current collectors or additives. The use of a carbon-based MOF cathode material effectively reduces the interaction with Mg. 2+ The Coulomb force, the porous structure is beneficial to Mg 2+ Rapid transport and the formation of conjugated structures also significantly improve the material's stability. This cathode material exhibits excellent performance in magnesium-ion battery performance testing, achieving a stability of 50 mA·g⁻¹. -1 At the current density, the highest discharge capacity after 100 cycles is 331 mAh·g. -1 Furthermore, after the first two activation cycles, the discharge specific capacity showed a steady increasing trend. CuPc-Ni MOF@NF was tested at current densities of 100, 200, 500, and 1000 mA·g. -1 At these times, the specific capacities of CuPc-Ni MOF@NF remained stable at 313.3, 271.8, 211, and 156.6 mAh·g, respectively. -1 It exhibits good multiplier capability. Attached Figure Description

[0026] Figure 1 This is a SEM image of the CuPc-Ni MOF@NF cathode material of this invention;

[0027] Figure 2 The image shows the XRD pattern of the CuPc-Ni MOF cathode material prepared in this invention.

[0028] Figure 3 The figures show (a) charge-discharge curves and (b) rate performance of the CuPc-Ni MOF@NF cathode material prepared in this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention in any way. Unless otherwise specified, the methods, materials, and equipment used in this invention are conventional methods, reagents, and equipment in this technical field, and all materials and equipment used are commercially available.

[0030] Example 1

[0031] The present invention provides a method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material, comprising the following steps: solvothermal extraction, rotary evaporation, extraction, column chromatography, and electrodeposition. The specific steps are as follows:

[0032] (1) 466.5 mg of the starting material 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine and 134 mg of anhydrous copper chloride were added to a flask and dispersed in 1.5 mL of n-hexanol solvent. Then, 0.25 mL of DBU was added. After the solution was purged with an oil pump and inert gas several times, the reaction apparatus was sealed and heated with stirring. After the reaction system cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure, and extraction was performed. After drying, filtration, rotary evaporation, and separation by silica gel column chromatography, 0.17 g of the blue-green solid product 2,3,9,10,16,17,23,24-octa-tosylamido phthalocyaninato cupric(II)(CuPc-NHTs) was finally obtained.

[0033] (2) The CuPc-NHTs obtained in step (1) were dispersed in concentrated sulfuric acid and deionized water. The mixed solution was heated and stirred to react. After the reaction system cooled to room temperature, the mixture was poured into a beaker containing ice water, and a large amount of blue-green precipitate immediately appeared. The precipitate was separated from the mother liquor by centrifugation, washed, and then dried in a vacuum drying oven to finally obtain the black product 2,3,9,10,16,17,23,24-octa-amino-phthalocyaninato cupric(II)(CuPc-NH2).

[0034] (3) Electrodeposition was performed using nickel foam as the working electrode and nickel foil as the counter electrode in a small (10 mL) dual-electrode apparatus. The CuPc-NH2 obtained in step (2) was added to a solution of DMF and 1-butyl-3-methylimidazolium chloride as the electrolyte for electrodeposition. During the electrodeposition process, black MOF particles grew on the nickel foam electrode. Finally, a CuPc-Ni MOF@NF positive electrode was obtained.

[0035] (4) The CuPc-Ni MOF@NF positive electrode obtained in step (3) is washed with deionized water and anhydrous ethanol and then dried.

[0036] Example 2

[0037] A method for preparing a 2D conductive nickel-copper bimetallic phthalocyanine metal-organic framework magnesium-ion battery cathode material.

[0038] (1) 4,5-Dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine (933 mg, 2.0 mmol) and anhydrous copper chloride (2.0 mmol) were added to a 10 mL flask and dispersed in 3 mL of n-hexanol solvent, followed by the addition of 0.5 mL of DBU. After repeated purging with an inert gas pump, the reaction apparatus was sealed and heated to 160 °C with stirring for 36 hours. After the reaction system cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure. The crude product was redissolved in CH2Cl2 / AcOH (25 mL: 5 mL) and extracted with 30 mL of water. After drying, filtration, rotary evaporation, and separation by silica gel column chromatography, using CH2Cl2 / MeOH (50:1) as the eluent, 0.34 g of blue-green solid CuPc-NHTs was finally obtained, with a yield of 34%.

[0039] (2) CuPc-NHTs (104 mg, 52.0 μmol) was added to a 10 mL round-bottom flask and dispersed in 3 mL concentrated sulfuric acid and 0.4 mL deionized water. The mixture was heated to 110 °C and stirred for 1 hour. After the reaction system cooled to room temperature, the mixture was poured into a beaker containing 20 mL of ice water, and a large amount of blue-green precipitate immediately appeared. The precipitate was separated from the mother liquor by centrifugation, and then washed successively with deionized water, 10% NaOH solution, deionized water, and ethanol. It was then dried in a vacuum drying oven to finally obtain 31 mg of black product CuPc-NH2, with a yield of 84%.

[0040] (3) Electrodeposition was performed using nickel foam as the working electrode and nickel foil as the counter electrode in a small (10 mL) two-electrode apparatus. Due to the poor solubility of CuPc-NH2 in water, DMF (4 mL) was used as the solvent, and 1-butyl-3-methylimidazolium chloride (0.1 M) was used as the electrolyte. The concentration of CuPc-NH2 was set to (7.2 × 10⁻⁶). -4M, 2 mg / 4 mL). To facilitate electrodeposition, 0.05 mL of concentrated ammonia was added. During electrode deposition at 1.1 V for 8 hours, the dark red solution gradually turned colorless, and black MOF particles grew on the nickel foam electrode. The final CuPc-Ni MOF@NF positive electrode was obtained.

[0041] (4) The CuPc-Ni MOF@NF positive electrode obtained in step (3) is washed with deionized water and anhydrous ethanol and then vacuum dried at 80°C for 6 hours.

[0042] Magnesium-ion battery assembly and electrochemical performance testing:

[0043] The assembly of the button cell using the nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material was completed in an anhydrous and oxygen-free glove box, and the electrochemical magnesium storage performance was tested using the Xinwei testing system. The specific steps are as follows:

[0044] (1) In an anhydrous and oxygen-free glove box, a button magnesium-ion battery was assembled with carbon cloth as the negative electrode (the mass ratio of activated carbon: carbon black: PVDF was 7:2:1) and bis(trifluoromethylsulfonyl)imide magnesium salt dissolved in ethylene glycol dimethyl ether as the electrolyte.

[0045] (2) Place the battery in the Xinwei test system, set the experimental parameters, and start the test.

[0046] like Figure 1 As shown, CuPc-NH2 reacts with Ni ionized from nickel foam. 2+ Coordination forms submicron-sized CuPc-Ni MOF particles, which cover the areas of nickel foam exposed to the electrolyte, thus achieving in-situ deposition of CuPc-Ni MOF in nickel foam.

[0047] like Figure 2 As shown, X-ray diffraction (XRD) measurements revealed the long-range ordered arrangement of CuPc-Ni MOF.

[0048] like Figure 3 As shown in Figure 3(a), the CuPc-Ni MOF@NF cathode material operates at 50 mA·g -1 The highest discharge specific capacity at current density can reach 331 mAh·g -1 The highest discharge capacity after 100 cycles is 331 mAh·g. -1 Furthermore, after the first two activation cycles, the discharge specific capacity shows a steady increasing trend. Figure 3 (b) Demonstrates the performance of CuPc-Ni MOF@NF at current densities of 100, 200, 500, and 1000 mA·g -1At these times, the specific capacities of CuPc-Ni MOF@NF remained stable at 313.3, 271.8, 211, and 156.6 mAh·g, respectively. -1 CuPc-Ni MOF@NF exhibited good rate capability in magnesium battery testing.

[0049] The meanings of the English abbreviations used in this invention are as follows:

[0050] DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene;

[0051] CH2Cl2 / MeOH: A mixture of dichloromethane and methanol;

[0052] DMF: N,N-dimethylformamide;

[0053] CuPc-NH2: Octaaminocopper phthalocyanine;

[0054] CuPc-Ni MOF: A type of metal-organic framework compound formed by linking octaaminocopper phthalocyanine with divalent nickel salt;

[0055] CuPc-Ni MOF@NF: 2D nickel-copper bimetallic phthalocyanine metal-organic framework magnesium-ion battery cathode material, namely CuPc-Ni MOF in-situ grown and deposited nickel foam.

[0056] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material, characterized in that, A conductive nickel-copper bimetallic phthalocyanine metal-organic framework (MOF) cathode material for magnesium-ion batteries uses 2D CuPc-Ni MOF as the positive electrode active material. The molecular formula of CuPc-Ni MOF is [Ni₂Cu(C₂O₃)₃]. 32 H 16 N 16 )] n CuPc-Ni MOF is deposited in situ on the surface of nickel foam and coated on the outer layer of the nickel foam substrate, exhibiting a stacked submicron-sized spherical morphology. Its preparation method includes the following steps: (1) Add the raw material 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine to the flask, disperse anhydrous copper chloride in n-hexanol solvent, and then add DBU; The solution is then sealed and reacted after being pumped with an inert gas and heated with stirring. After the reaction system was cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure. The crude product was redissolved in CH2Cl2 / AcOH and then extracted with water. After drying, filtration, rotary evaporation, and separation by silica gel column chromatography, a blue-green solid product was finally obtained. (2) The blue-green solid product obtained in step (1) was added to a round-bottom flask and dispersed in concentrated sulfuric acid and deionized water. The mixture was heated and stirred. After the reaction system cooled to room temperature, the mixture was poured into a beaker containing ice water. A large amount of blue-green precipitate appeared immediately. The precipitate was separated from the mother liquor by centrifugation and then washed with deionized water, 10% NaOH solution, deionized water and ethanol in sequence. The mixture was then dried under vacuum to finally obtain the black product CuPc-NH2. (3) Electrodeposition was performed in a small dual-electrode device using nickel foam as the working electrode and nickel foil as the counter electrode. The black product CuPc-NH2 obtained in step (2) was added to a solution of DMF and 1-butyl-3-methylimidazolium chloride as the electrolyte for electrodeposition. During the electrodeposition process, the dark red solution gradually turned colorless, and black MOF particles were grown on the nickel foam electrode to obtain CuPc-Ni MOF@NF positive electrode sheet. (4) The CuPc-Ni MOF@NF positive electrode sheet from step (3) is washed with deionized water and anhydrous ethanol and then dried under vacuum to obtain the final product.

2. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In step (1), the molar ratio of 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine and anhydrous copper chloride is 1:1; the volume ratio of n-hexanol and DBU is 6:

1.

3. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In step (1), the solution is sealed and reacted after being replaced by an oil pump and an inert gas. The heating temperature is 120-160℃ and the stirring reaction time is 24-72 hours.

4. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In step (1), the silica gel column is used for separation, and the eluent is CH2Cl2 / MeOH.

5. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 4, characterized in that, In step (1), the volume ratio of CH2Cl2 to AcOH in the crude product solvent is 2 to 5:1, and the volume ratio of CH2Cl2 to water in the extractant is 1:1; the volume ratio of CH2Cl2 to MeOH in the eluent is 30 to 50:

1.

6. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In step (2), the volume ratio of concentrated sulfuric acid to deionized water is 10:1; the temperature of the mixed solution is 100-120℃, and the reaction time is 1-4 hours.

7. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In the electrodeposition process of step (3), DMF is used as a solvent and 1-butyl-3-methylimidazolium chloride is used as an electrolyte with a concentration of 0.1M.

8. The method for preparing a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material according to claim 1, characterized in that, In step (3), the concentration of CuPc-NH2 added during electrodeposition is 7.2 × 10⁻⁶. -4 M, reaction voltage is 1.0 to 1.2 V, reaction time is 6 to 10 hours.

9. The application of a nickel-copper bimetallic phthalocyanine-based organic framework magnesium-ion battery cathode material in the preparation of magnesium-ion batteries, characterized in that... In an anhydrous and oxygen-free glove box, a magnesium-ion battery was assembled with a CuPc-Ni MOF@NF positive electrode sheet, activated carbon cloth, glass fiber, stainless steel button battery components, and an electrolyte solution of bis(trifluoromethanesulfonyl)imide magnesium salt dissolved in ethylene glycol dimethyl ether.

Images