A conductive nickel phthalocyanine metal-organic framework sodium ion battery cathode material, a preparation method therefor and applications thereof

Abstract

The application belongs to the field of battery materials, and particularly relates to a kind of conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material and its preparation method and application.NiPc-Ni MOF molecular formula is [Ni3(C 32 H 16 N 16 )] n ;NiPc-Ni MOF molecule is in situ deposited on the surface of foam nickel, and is coated on the outer layer of foam nickel matrix, and presents a stacked sub-micron spherical morphology.The application adopts solvothermal, rotary evaporation, extraction and chromatographic column separation method and electrodeposition method to prepare conductive NiPc-Ni MOF@NF positive electrode material, which can be directly used as a positive electrode sheet without adding additional current collector and additives;Phthalocyanine-based MOFs have high intrinsic conductivity, which is conducive to accelerating electron conduction, the porous structure is beneficial to Na + Fast transmission, the formation of extended conjugated structure also greatly improves the stability of the material, and excellent cycle performance and rate performance can be shown.

Description

Technical Field

[0001] The present invention belongs to the field of battery materials, and in particular relates to a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material, a preparation method and an application thereof. Background Art

[0002] The growing demand for efficient electrical energy storage systems has stimulated the development of high-capacity and low-cost rechargeable batteries. Lithium-ion batteries (Li-ion) meet the high energy and power density requirements of portable electronic devices and electronic vehicles and are currently considered the most promising of these batteries. However, despite these advantages, the low natural abundance of lithium hinders the sustainable development of Li-ion batteries.

[0003] Given the relatively low cost of sodium sources, sodium-ion batteries have recently attracted increasing attention as a possible alternative to lithium-ion batteries. In particular, several organic materials have been shown to have unique redox properties and electrical conductivity that can be regulated by controlling the structure of the corresponding π-conjugated framework. Metal-organic frameworks (MOFs) connected in two-dimensional (2D) or three-dimensional manners have been used in various metal-ion batteries, among which 2D conductive MOFs are regarded as a new type of organic electrode material for lithium-ion, sodium-ion, potassium-ion and other batteries. Their organic ligands and metal sites are first connected by self-assembly to form a 2D layered structure, and the layers are stacked through π-π interactions to form a bulk structure, while forming a continuous one-dimensional pore structure. Na + (By Li + Much larger) can effectively enter the one-dimensional pore structure of MOFs materials, which is expected to benefit Na by improving energy density and promoting ion transport. + Storage applications. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material and its preparation method and application. The metal organic framework is abundant in source, environmentally friendly, has high intrinsic conductivity, rich redox active sites and ion transport channels, and the obtained positive electrode material has good stability and conductivity, which can improve the cycle stability and rate performance of the battery.

[0005] The technical solutions adopted are:

[0006] A conductive nickel phthalocyanine metal organic framework sodium ion battery cathode material, using 2D NiPc-Ni MOF, wherein the NiPc-Ni MOF molecular formula is [Ni3(C 32 H 16 N 16 )] n;NiPc-Ni MOF molecules are in situ deposited on the surface of nickel foam and coated on the outer layer of nickel foam matrix, presenting a stacked submicron spherical morphology.

[0007] A method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material comprises the following steps:

[0008] (1) Add the raw material 4,5-dicyano-N,N'-di-p-toluenesulfonyl o-phenylenediamine and anhydrous nickel chloride dispersed in n-hexanol solvent into a flask, and then add DBU;

[0009] The solution is sealed and reacted after being replaced with an inert gas by an oil pump, and heated and stirred;

[0010] After the reaction system was cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure, and the obtained crude product was redissolved in CH2Cl2 / AcOH and extracted with water; the product was dried, filtered, rotary evaporated, and separated by silica gel chromatography to obtain a dark green solid product;

[0011] (2) The dark green solid product obtained in step (1) was added to a round-bottom flask and dispersed in concentrated sulfuric acid and deionized water, heated and stirred; after the reaction system was cooled to room temperature, the mixture was poured into a beaker filled with ice water, and a large amount of green precipitate immediately appeared; 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, and vacuum dried to finally obtain a black product;

[0012] (3) Electrodeposition was performed in a small two-electrode device using nickel foam as a working electrode and nickel foil as a counter electrode. The black product obtained in step (2) was added to a solution of DMF and 1-butyl-3-methylimidazolium chloride as an electrolyte for electrodeposition. During the electrodeposition process, the dark red solution gradually turned colorless, and black MOF particles grew on the nickel foam electrode to obtain a NiPc-NiMOF@NF positive electrode sheet.

[0013] (4) The NiPc-NiMOF@NF positive electrode sheet of step (3) was washed with deionized water and anhydrous ethanol, and then dried under vacuum.

[0014] Preferably, in step (1), the molar ratio of 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine to anhydrous nickel chloride is 1:1; and the volume ratio of n-hexanol to DBU is 6:1.

[0015] Preferably, in the step (1), the solution is sealed for reaction after being replaced by an oil pump-inert gas, the heating temperature is 120-160° C., and the stirring reaction time is 24-72 hours.

[0016] Preferably, in step (1), separation is performed using a silica gel column chromatography, and the eluent is CH2Cl2 / MeOH.

[0017] Preferably, in step (1), the volume ratio of CH2Cl2 (dichloromethane) and AcOH (acetic acid) in the crude product solvent is 25:5, and the volume ratio with the extractant water is 1:1; the volume ratio of CH2Cl2 and MeOH (methanol) in the eluent is 50:1.

[0018] Preferably, in step (2), the volume ratio of concentrated sulfuric acid to deionized water is 10:1; the temperature of heating the mixed solution is 100-120° C., and the reaction time is 1-4 hours.

[0019] 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.

[0020] Preferably, in step (3), the concentration of NiPc-NH2 added during the electrodeposition process is 7.2×10 -4 M, the reaction voltage was 1.1 V, and the reaction time was 8 hours.

[0021] A conductive nickel phthalocyanine metal-organic framework sodium ion battery cathode material is used in the preparation of sodium ion batteries. In an anhydrous and oxygen-free glove box, the NiPc-NiMOF@NF cathode plate is assembled with a sodium plate, glass fiber, a stainless steel button battery component, and an electrolyte of NaPF6 dissolved in diethylene glycol dimethyl ether to obtain a sodium ion battery.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention uses 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl-o-phenylenediamine as a raw material and prepares a conductive NiPc-NiMOF@NF positive electrode material through solvent thermal, rotary evaporation, extraction, chromatographic column separation and electrodeposition. The material can be directly used as a positive electrode plate without the addition of an external current collector and additives.

[0024] The present invention uses phthalocyanine-based MOFs with high intrinsic conductivity, which is conducive to accelerating electron conduction, and the porous structure is conducive to Na + Rapid transmission and the formation of conjugated structure also greatly improve the stability of the material.

[0025] The positive electrode material prepared by the present invention shows excellent cycle performance and rate performance in sodium ion battery performance test. -1 At this current density, the highest discharge capacity after 800 cycles reached 399.23 mAh g -1 ; at 1A·g -1At this current density, the discharge capacity after 1000 cycles reaches 182.85 mAh g -1 , the discharge capacity shows a steady growth trend; and at 10A·g -1 The discharge capacity can reach 113.91 mAh g at high current density. -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the SEM image of the NiPc-Ni MOF@NF cathode material prepared in the present invention;

[0027] Figure 2 HRTEM image of the NiPc-Ni MOF material prepared in the present invention;

[0028] Figure 3 (a) 0.1A·g of NiPc-Ni MOF@NF cathode material prepared in the present invention -1 Cycling performance at current density (b) 1A·g -1 (c) Cycling performance and rate performance at different current densities. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific examples. It should be understood that the specific examples described herein are only used to illustrate the present invention and are not intended to limit the present invention in any way. Unless otherwise specified, the methods, materials and equipment used in the present invention are conventional methods, reagents and equipment in the art, and the materials and equipment used can be obtained from commercial sources.

[0030] Example 1

[0031] The present invention provides a method for preparing a 2D conductive nickel phthalocyanine metal organic framework sodium ion battery cathode material, comprising the following steps: solvent thermal, rotary evaporation, extraction, chromatographic column separation, and electrodeposition. The specific steps are as follows:

[0032] (1) Add 1866 mg of raw material 4,5-dicyano-N,N'-di-p-methylbenzenesulfonyl o-phenylenediamine and 518 mg of anhydrous nickel chloride dispersed in 6 mL of n-hexanol solvent into the flask, and then add 1 mL of DBU. After the solution is replaced with an oil pump-inert gas several times, the reaction device is sealed and heated with stirring. After the reaction system is cooled to room temperature, the solvent is removed by vacuum rotary evaporation and extraction is performed. After drying, filtration, rotary evaporation, and silica gel column separation, 0.66 g of dark green solid product 2,3,9,10,16,17,23,24-octa-tosylamido phthalocyaninato nickel(II) (NiPc-NHTs) is finally obtained with a yield of 34%;

[0033] (2) The NiPc-NHTs obtained in step (1) are dispersed in concentrated sulfuric acid and deionized water. The mixed solution is heated and stirred for reaction. After the reaction system is cooled to room temperature, the mixture is poured into a beaker filled with ice water, and a large amount of green precipitate immediately appears. The precipitate is separated from the mother liquor by centrifugation, washed, and dried in a vacuum drying oven to finally obtain a black product 2,3,9,10,16,17,23,24-octa-amino-phthalocyaninato nickel(II) (NiPc-NH2) with a yield of 84%.

[0034] (3) Electrodeposition was performed in a small (10 mL) two-electrode apparatus using nickel foam as the working electrode and nickel foil as the counter electrode. The NiPc-NH2 obtained in (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 NiPc-NiMOF@NF positive electrode was obtained.

[0035] (4) The NiPc-NiMOF@NF positive electrode obtained in step (3) was washed with deionized water and anhydrous ethanol and then dried.

[0036] Example 2

[0037] A method for preparing a 2D conductive nickel phthalocyanine metal-organic framework sodium ion battery positive electrode material.

[0038] (1) 4,5-Dicyano-N,N'-di-p-toluenesulfonyl o-phenylenediamine (933 mg, 2.0 mmol) and anhydrous nickel chloride (2.0 mmol) were dispersed in 3 mL of n-hexanol solvent in a 10 mL flask, followed by the addition of 0.5 mL of DBU. After multiple cycles of oil pump-inert gas replacement, the reaction apparatus was sealed, heated to 160°C, and stirred for 36 hours. 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 (25 mL:5 mL) and extracted with 30 mL of water. After drying, filtration, rotary evaporation, and silica gel column separation, CH2Cl2 / MeOH (50:1) was used as the eluent to obtain 0.34 g of dark green solid NiPc-NHTs.

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

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

[0041] (4) The NiPc-NiMOF@NF positive electrode sheet obtained in step (3) was washed with deionized water and anhydrous ethanol, and then dried in a vacuum oven at 80 °C for 6 h.

[0042] Sodium-ion battery assembly and electrochemical performance test:

[0043] The assembly of the button cell of the 2D conductive nickel phthalocyanine metal organic framework sodium-ion battery positive electrode material was completed in an anhydrous and anaerobic glove box, and the electrochemical sodium storage performance was completed in a Neware test system. The specific steps are as follows:

[0044] (1) In an anhydrous and anaerobic glove box, a sodium sheet was used as the negative electrode, and NaPF6 was dissolved in diethylene glycol dimethyl ether as the electrolyte to assemble a button sodium-ion battery;

[0045] (2) The battery was placed in a Neware test system, the experimental parameters were set, and the test was started.

[0046] As shown in Figure 1 , NiPc-NH2 coordinates with the ionized Ni 2+ on the NF to form sub-micron NiPc-Ni MOF particles, which cover the position of the NF exposed to the electrolyte, realizing in-situ deposition of NiPc-Ni MOF on the NF.

[0047] As shown in Figure 2As shown, high-resolution transmission electron microscopy (HRTEM) images intuitively show the long-range ordered arrangement of NiPc-Ni MOF.

[0048] like Figure 3 As shown in the graph of cycle number and specific capacity, Figure 3(a) is at 100mA·g -1 At this current density, the highest discharge capacity after 800 cycles reached 399.23 mAh g -1 ; Figure 3 (b) At 1A·g -1 At this current density, the discharge capacity after 1000 cycles reaches 182.85 mAh g -1 , the discharge capacity shows a steady growth trend; such as Figure 3 As shown in (c), NiPc-NiMOF@NF exhibits excellent electrochemical performance at current densities of 200, 400, 800, 1000, 2000, 4000, and 8000 mA·g -1 When the specific capacities of NiPc-Ni MOF@NF are stable at 233.7, 217.7, 204.2, 198.9, 197.2, 157.8 and 122.2 mAh·g, respectively. -1 , and at 10A·g -1 The discharge capacity can reach 113.91 mAh g at high current density. -1 , showing excellent cycle performance and rate performance.

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

[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] NiPc-NH2: octaaminonickel phthalocyanine;

[0054] NiPc-Ni MOF: A type of metal-organic framework compound formed by connecting octaamino nickel phthalocyanine with a divalent nickel salt;

[0055] NiPc-Ni MOF@NF: 2D nickel phthalocyanine metal-organic framework sodium-ion battery cathode material, namely NiPc-Ni MOF in situ grown and deposited nickel foam;

[0056] NaPF6: sodium hexafluorophosphate.

[0057] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material, characterized in that: 2D NiPc-NiMOF is used as the electrode active material, wherein the molecular formula of NiPc-Ni MOF is [Ni3(C 32 H 16 N 16 )] n ; NiPc-Ni MOF is in situ deposited on the surface of nickel foam and coated on the outer layer of nickel foam substrate, presenting a stacked submicron spherical morphology.

2. A method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material, characterized in that: The following steps are involved: (1) Add the raw material 4,5-dicyano-N,N'-di-p-toluenesulfonyl o-phenylenediamine and anhydrous nickel chloride dispersed in n-hexanol solvent into a flask, and then add DBU; The solution is sealed and reacted after being replaced by an oil pump-inert gas, and heated and stirred; After the reaction system was cooled to room temperature, the solvent was removed by rotary evaporation under reduced pressure, and the obtained crude product was redissolved in CH2Cl2 / AcOH and extracted with water; the product was dried, filtered, rotary evaporated, and separated by silica gel chromatography to obtain a dark green solid product; (2) The dark green solid product obtained in step (1) was added to a round-bottom flask and dispersed in concentrated sulfuric acid and deionized water, heated and stirred; after the reaction system was cooled to room temperature, the mixture was poured into a beaker filled with ice water, and a large amount of green precipitate immediately appeared; 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, and vacuum dried to finally obtain a black product; (3) Electrodeposition was performed in a small two-electrode device using nickel foam as a working electrode and nickel foil as a counter electrode. The black product obtained in step (2) was added to a solution of DMF and 1-butyl-3-methylimidazolium chloride as an electrolyte for electrodeposition. During the electrodeposition process, the dark red solution gradually turned colorless, and black MOF particles grew on the nickel foam electrode to obtain a NiPc-NiMOF@NF positive electrode sheet. (4) The NiPc-NiMOF@NF positive electrode sheet of step (3) was washed with deionized water and anhydrous ethanol, and then dried under vacuum.

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

1.

4. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 2, characterized in that: In the step (1), the solution is sealed and reacted after being replaced by an oil pump-inert gas, the heating temperature is 120-160° C., and the stirring reaction time is 24-72 hours.

5. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 2, characterized in that: In the step (1), silica gel chromatography column is used for separation, and CH2Cl2 / MeOH is used as the eluent.

6. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 5, characterized in that: In step (1), the volume ratio of CH2Cl2 and AcOH in the crude product solvent is 25:5, and the volume ratio of CH2Cl2 to AcOH in the extractant water is 1:1; the volume ratio of CH2Cl2 and MeOH in the eluent is 50:

1.

7. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 2, characterized in that: In step (2), the volume ratio of concentrated sulfuric acid to deionized water is 10:1; the mixed solution is heated at a temperature of 100-120° C., and the reaction time is 1-4 hours.

8. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 2, characterized in that: During the electrodeposition process of step (3), DMF was used as a solvent and 1-butyl-3-methylimidazolium chloride was used as an electrolyte with a concentration of 0.1M.

9. The method for preparing a conductive nickel phthalocyanine metal organic framework sodium ion battery positive electrode material according to claim 2, characterized in that: In step (3), the concentration of NiPc-NH2 added during the electrodeposition process is 7.2×10 -4 M, the reaction voltage was 1.1 V, and the reaction time was 8 hours.

10. Application of a conductive nickel phthalocyanine metal organic framework sodium ion battery cathode material in the preparation of a sodium ion battery, characterized in that: In an anhydrous and oxygen-free glove box, the NiPc-NiMOF@NF positive electrode sheet was assembled with a sodium sheet, glass fiber, a stainless steel button battery assembly, and an electrolyte of NaPF6 dissolved in diethylene glycol dimethyl ether to obtain a sodium ion battery.

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