Preparation method and application of flexible CuNi-P@graphene lithium ion battery film

Abstract

The application provides a preparation method of a flexible CuNi-P@graphene lithium ion battery film, and the preparation method comprises the following steps: preparing a CHNs@graphene oxide film, preparing a HKUST-1@graphene oxide film, preparing a CuNi-LDH@graphene oxide film, and obtaining the flexible CuNi-P@graphene lithium ion battery film. The flexible graphene-based film is synthesized by combining a vacuum filtration method, a hydrothermal method and high-temperature calcination, MOF precursors are introduced to form the flexible CuNi-P@graphene lithium ion battery film electrode, and the porous CuNi-P derived from the MOF is combined with the graphene, so that the Li ion migration efficiency can be effectively promoted, the negative electrode material expansion coefficient can be reduced, and the electrochemical performance can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method and application of a flexible CuNi-P@graphene lithium ion battery film. BACKGROUND

[0002] Due to the large-scale use of fossil fuels, the environment has been seriously polluted, and the development of clean, pollution-free and sustainable energy has become one of the hotspots of scientific research. Lithium ion batteries have been widely used in people's daily life due to their wide working temperature range, long cycle life, good safety performance and no memory effect. For batteries, electrode materials play a crucial role in performance. However, the traditional commercial graphite negative electrode cannot meet people's requirements due to its low theoretical capacity. Therefore, it is urgent to develop lithium ion battery electrode materials with high capacity and high rate performance.

[0003] With the vigorous development of metal organic frameworks (MOF) as electrode materials, MOFs with special structures and their derivatives open up a new field for the research and development of electrode materials for energy storage devices. MOF materials are generally 3D porous structures and are ideal precursors. After a series of processing, various derivatives have high porosity, large specific surface area, structural and functional diversity, open lithium ion transmission channels and other characteristics and are widely used in lithium ion batteries. However, the MOF derivative compounds obtained at present have defects such as poor conductivity, obvious volume change in the charging and discharging process, and are difficult to achieve excellent rate performance and cycle performance when applied to lithium batteries. SUMMARY

[0004] In view of the deficiencies in the prior art, the application provides a preparation method and application of a flexible CuNi-P@graphene lithium ion battery film, which realizes the following application purposes: after the prepared flexible CuNi-P@graphene lithium ion battery film is applied to a lithium battery, the rate performance and cycle performance are good.

[0005] To solve the above technical problems, the application adopts the following technical solutions:

[0006] A preparation method of a flexible CuNi-P@graphene lithium ion battery film, the preparation method comprises the following steps: preparing a CHNs@graphene oxide film, preparing a HKUST-1@graphene oxide film, preparing a CuNi-LDH@graphene oxide film, and obtaining the flexible CuNi-P@graphene lithium ion battery film.

[0007] The method for preparing the CHNs@graphene oxide film comprises the following steps: uniformly mixing a copper nitrate solution and an ethanolamine solution, aging at room temperature for 23-25 hours to obtain solution A; diluting graphene oxide slurry to 0.8-1.2 mg / mL to obtain solution B; mixing solution A and solution B according to a volume ratio of 1:0.9-1.1, stirring for 0.8-1.2 hours, and then performing vacuum filtration and drying to obtain the CHNs@graphene oxide film.

[0008] The concentration of the copper nitrate solution is 1.8-2.2 mM, and the concentration of the ethanolamine solution is 0.6-0.8 mM; the volume ratio of the copper nitrate solution to the ethanolamine solution is 1:0.9-1.1.

[0009] The drying temperature in the step of preparing the CHNs@graphene oxide film is 58-62℃, and the drying time is 11-13 hours.

[0010] The method for preparing the HKUST-1@graphene oxide film comprises the following steps: completely immersing the CHNs@graphene oxide film in a uniform trimesic acid solution with a concentration of 9-11 mM at room temperature for 12-24 hours, and then performing washing and drying to obtain the HKUST-1@graphene oxide film.

[0011] The drying temperature in the step of preparing the HKUST-1@graphene oxide film is 58-62℃, and the drying time is 23-25 hours.

[0012] The method for preparing the CuNi-LDH@graphene oxide film comprises the following steps: completely immersing the HKUST-1@graphene oxide film in a nickel nitrate solution, reacting at 60-80℃ for 1-2 hours, and then performing washing and drying to obtain the CuNi-LDH@graphene oxide film.

[0013] The drying temperature in the step of preparing the CuNi-LDH@graphene oxide film is 58-62℃, and the drying time is 23-25 hours.

[0014] The solvent of the nickel nitrate solution is deionized water and anhydrous ethanol, and the mass ratio of the nickel nitrate to the deionized water and the anhydrous ethanol is 0.05-0.1:20:7.8-8.

[0015] The method for preparing the flexible CuNi-P@graphene lithium ion battery film comprises the following steps: mixing the CuNi-LDH@graphene oxide film with NaH2PO2 according to a mass ratio of 1:4.8-5.2, heating to 395-405℃ at a speed of 1.8-2.2℃ / min under a N2 atmosphere, and then maintaining the temperature for 1.9-2.1 hours to obtain the flexible CuNi-P@graphene lithium ion battery film.

[0016] The flexible CuNi-P@graphene lithium ion battery film is used as a negative electrode material to assemble a lithium ion battery.

[0017] Preferably, in the step of preparing the CuNi-LDH@ graphene oxide film, the reaction temperature is preferably 70-80°C, and the reaction time is preferably 2h.

[0018] Further preferably, in the step of preparing the CuNi-LDH@ graphene oxide film, the reaction temperature is preferably 70-80°C, and the reaction time is preferably 2h; the mass ratio of nickel nitrate to deionized water to anhydrous ethanol is 0.1:20:7.8-8.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] (1) The flexible graphene-based film is synthesized by combining vacuum filtration, hydrothermal method and high-temperature calcination, and the MOF precursor is introduced to form a flexible CuNi-P@ graphene lithium ion battery thin film electrode. The porous CuNi-P derived from the MOF and the graphene can effectively promote the Li ion migration efficiency, reduce the negative material expansion coefficient, and promote the improvement of the electrochemical performance.

[0021] (2) The flexible CuNi-P@ graphene lithium ion battery thin film prepared by the application is used as a negative material to prepare a lithium ion button cell, and the specific capacity is 561.2-750.6 mAh·g -1 under a current density of 0.1 A·g -1 , and the specific capacity of the preferred technical solution is 711.3-750.6 mAh·g -1 .

[0022] (3) The flexible CuNi-P@ graphene lithium ion battery thin film prepared by the application is used as a negative material to prepare a lithium ion button cell, and the cycle performance is good under different rates (0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 and 0.1 A·g -1 ). Under a current density of 0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 and 2 A·g -1 , the specific capacity of the battery is maintained at 561.2-750.6 mAh·g -1 , 280.4-509.5 mAh·g -1 , 188.6-417.3 mAh·g -1 and 90.5-312.3 mAh·g -1when the current density returns to 0.1 A·g -1 , the specific capacity returns to 433.7-738.4 mAh·g -1 , reaching 77.3-98.4% of the original level;

[0023] The preferred technical solution achieves the effect that when the current density returns to 0.1 A·g -1 , the specific capacity returns to 90.7-98.4% of the original level.

[0024] The further preferred technical solution achieves the effect that when the current density returns to 0.1 A·g -1 , the specific capacity returns to 94.9-98.4% of the original level.

[0025] (4) The flexible CuNi-P@graphene lithium ion battery film prepared by the application is used as a negative electrode material to prepare a lithium ion button cell, and the coulomb efficiency can be maintained at about 98% after the third cycle, indicating that the composite film has good reversibility in the charging and discharging process. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The XRD graph of the flexible CuNi-P@graphene lithium ion battery film prepared in Example 1;

[0027] Figure 2 The SEM graph of the flexible CuNi-P@graphene lithium ion battery film prepared in Example 1;

[0028] Figure 3 The charge-discharge curve graph of the lithium ion battery assembled by the flexible CuNi-P@graphene lithium ion battery film prepared in Example 1;

[0029] Figure 4 The cycle performance graph of the lithium ion battery assembled by the flexible CuNi-P@graphene lithium ion battery film prepared in Example 1 at different rates;

[0030] Figure 5 The stability performance graph of the lithium ion battery assembled by the flexible CuNi-P@graphene lithium ion battery film prepared in Example 1 at a current density of 0.1 A g -1 ;

[0031] Figure 6 The cycle performance graph of the lithium ion battery assembled by the flexible CuNi-P@graphene lithium ion battery film prepared in Example 2 at different rates;

[0032] Figure 7 The cycle performance graph of the lithium ion battery assembled by the flexible CuNi-P@graphene lithium ion battery film prepared in Example 3 at different rates;

[0033] Figure 8 Cycling performance plots of lithium ion batteries assembled with flexible CuNi-P@graphene lithium ion battery films prepared in Example 4 at different rates;

[0034] Figure 9 Cycling performance plots of lithium ion batteries assembled with flexible CuNi-P@graphene lithium ion battery films prepared in Example 5 at different rates;

[0035] Figure 10 Cycling performance plots of lithium ion batteries assembled with flexible CuNi-P@graphene lithium ion battery films prepared in Example 6 at different rates. DETAILED DESCRIPTION

[0036] The application will be described in greater detail below with reference to the embodiments. However, the application is not limited to the following embodiments.

[0037] Unless otherwise defined, the terms (including technical and scientific terms) used herein should be interpreted as being commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0038] In the following examples: the CHNs are the abbreviation of copper hydroxide nanowires, the HKUST-1 is Cu-MOF,

[0039] The CuNi-LDH is CuNi double hydroxide, and CuNi-P is CuNi bimetallic phosphide.

[0040] Example 1 A method for preparing a flexible CuNi-P@graphene lithium ion battery film

[0041] (1) Preparation of CHNs@graphene oxide film: 100 mL of Cu(NO3)2·3H2O (2 mM) solution and 100 mL of ethanolamine (0.7 mM) solution were mixed uniformly, and solution A was obtained after aging at room temperature for 24 h; 6 mL of graphene oxide slurry (10 mg / mL) was diluted to 1 mg / mL to obtain solution B; 60 mL of solution A was mixed with the same volume of solution B, and stirred at room temperature for 1 h; after the reaction was completed, vacuum filtration was performed, and the product was dried at 60°C for 12 h to obtain the CHNs@graphene oxide film.

[0042] (2) Preparation of HKUST-1@ graphene oxide membrane: the dried CHNs@ graphene oxide membrane was completely immersed in a 10 mM uniform tribenzoic acid (H3BTC) solution at room temperature for 24 h, washed, and dried at 60 °C for 24 h to obtain the HKUST-1@ graphene oxide membrane.

[0043] (3) Preparation of CuNi-LDH@ graphene oxide membrane: the dried HKUST-1@ graphene oxide membrane of step (2) was completely immersed in a polytetrafluoroethylene-lined autoclave containing a nickel nitrate solution, the solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol, the mass ratio of the three was 0.1:20:7.9, and the reaction was carried out at 80 °C for 2 h, and the CuNi-LDH@ graphene oxide membrane was obtained after washing and drying at 60 °C for 24 h.

[0044] (4) Preparation of flexible CuNi-P@ graphene lithium ion battery thin film: the dried CuNi-LDH@ graphene oxide membrane of step (3) was mixed with NaH2PO2 at a mass ratio of 1:5, heated to 400 °C at a rate of 2 °C / min under N2 atmosphere, and then reacted at 400 °C for 2 h to obtain the flexible CuNi-P@ graphene lithium ion battery thin film.

[0045] The XRD pattern of the flexible CuNi-P@ graphene lithium ion battery thin film prepared in Example 1 is shown in FIG. 1, and the triangularly marked peaks are the diffraction peaks of graphene, but the diffraction peaks are not obvious due to the poor crystallinity of CuNi-P. Figure 1

[0046] The SEM image of the flexible CuNi-P@ graphene lithium ion battery thin film prepared in Example 1 is shown in FIG. 2, and the CuNi-P polyhedron is combined with graphene. Figure 2

[0047] The flexible CuNi-P@ graphene lithium ion battery thin film material prepared in Example 1 was assembled into a lithium ion button cell: in an argon-filled glove box, the flexible CuNi-P@ graphene lithium ion battery thin film was used as the working electrode, microporous polypropylene was used as the separator, lithium sheet was used as the counter electrode, and the electrolyte was selected to be a mixture of 1 mol / L LiFP6, ethylene carbonate and dimethyl phosphate (volume ratio 1:1), then the battery shell was tightly sealed in a packaging machine, and the battery was placed for more than 12 hours before testing, and a two-electrode system was used to test the charge and discharge performance of the battery.

[0048] The lithium ion button cell was prepared using the flexible CuNi-P@ graphene lithium ion battery thin film prepared in Example 1 as the negative electrode material, and the charge and discharge curves of the first, fifth and tenth cycles at a current density of 0.1 A·g -1 -1 were as shown in FIG. 3.​​Figure 3 As shown in Figure 3 Figure 6, in the first cycle, the constant slope with several small platforms indicates a multiphase transition between CuNi-P and lithium. The initial discharge and charge capacities are 1141.4 mAh·g -1 and 625.6 mAh·g -1 , respectively. The irreversible capacity loss can be caused by different irreversible processes, such as interfacial lithium storage, SEI layer and organic conductive polymer formation, and electrolyte decomposition.

[0049] The fifth discharge and charge capacities are 551.6 mAh·g -1 and 550.3 mAh·g -1 , respectively. The tenth discharge and charge capacities are 543.3 mAh·g -1 and 542.7 mAh·g -1 , respectively.

[0050] The flexible CuNi-P@graphene lithium ion battery film prepared in Example 1 was used as the negative electrode material to prepare a lithium ion button cell, and the cycle performance diagram at different rates (0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 and 0.1 A·g -1 ) is as shown in Figure 4 , and as can be seen from Figure 4 , when the current density returns to 0.1 A·g -1 , the capacity of the film is 738.4 mAh·g -1 , reaching 98.4% of the original level, basically returning to the original level, indicating that it has good recoverability. At 0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 and 2 A·g -1 current density, the capacity is maintained at 750.6 mAh·g -1 , 506.3 mAh·g -1 , 402.4 mAh·g -1 and 310.5 mAh·g -1 .

[0051] The flexible CuNi-P@graphene lithium ion battery film prepared in Example 1 was used as the negative electrode material to prepare a lithium ion button cell, and the stability test results are as shown in Figure 5 , and as can be seen from Figure 5 , the battery has a capacity of 738.4 mAh·g -1The capacity of the flexible CuNi-P@graphene lithium ion battery film prepared in Example 2 basically does not attenuate after 50 cycles, and still maintains at 790 mAh·g -1 In addition, the coulombic efficiency can be maintained at about 98% after the third cycle, indicating that the composite film has good reversibility in the charging and discharging process.

[0052] Example 2: A preparation method of a flexible CuNi-P@graphene lithium ion battery film

[0053] (1) Preparation of CHNs@graphene oxide film: 100 mL of Cu(NO3)2·3H2O (2 mM) solution and 100 mL of ethanolamine (0.7 mM) solution were mixed uniformly, and solution A was obtained after aging at room temperature for 24 h; 6 mL of graphene oxide slurry (10 mg / mL) was diluted to a solution B of 1 mg / mL, and the same volume of solution B was mixed with 60 mL of solution A, and stirred at room temperature for 1 h. After the reaction was completed, vacuum filtration was performed, and the CHNs@graphene oxide film was obtained by drying at 60℃ for 12 h.

[0054] (2) Preparation of HKUST-1@graphene oxide film: the dried CHNs@graphene oxide film in step (1) was completely immersed in a 10 mM uniform tribenzoic acid (H3BTC) solution at room temperature for 24 h, washed, and dried at 60℃ for 24 h to obtain the HKUST-1@graphene oxide film.

[0055] (3) Preparation of CuNi-LDH@graphene oxide film: the dried HKUST-1@graphene oxide film in step (2) was completely immersed in a polytetrafluoroethylene-lined autoclave containing a nickel nitrate solution, and the solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol. The mass ratio of nickel nitrate, deionized water and anhydrous ethanol was 0.05:20:7.9, and the reaction was carried out at 80℃ for 2 h. After washing and drying at 60℃ for 24 h, the CuNi-LDH@graphene oxide film was obtained.

[0056] (4) Preparation of flexible CuNi-P@graphene lithium ion battery film: the dried CuNi-LDH@graphene oxide film in step (3) was mixed with NaH2PO2 at a mass ratio of 1:5, and heated to 400℃ at a speed of 2℃ / min under N2 atmosphere, and then reacted at 400℃ for 2 h to obtain the flexible CuNi-P@graphene lithium ion battery film.

[0057] The flexible CuNi-P@graphene lithium ion battery film prepared in Example 2 was used as a negative electrode material to prepare a lithium ion button cell, and the lithium ion button cell had a capacity of 790 mAh·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g-1 and 0.1 A·g -1 ) cycle performance chart as shown in Figure 2; its capacity at 0.1 A·g Figure 6 -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 maintained at 750.3 mAh·g -1 , 500.4 mAh·g -1 , 417.3 mAh·g -1 and 312.3 mAh·g -1 . When the current density returned to 0.1 A·g -1 , the capacity of the film was 680.5 mAh·g -1 , reaching 90.7% of the original level, and basically returning to the original level, indicating that it has good recoverability.

[0058] Example 3 A preparation method of a flexible CuNi-P@graphene lithium ion battery film

[0059] (1) Preparation of CHNs@graphene oxide film: 100 mL of Cu(NO3)2·3H2O (2 mM) solution and 100 mL of ethanolamine (0.7 mM) solution were mixed uniformly, and solution A was obtained after aging at room temperature for 24 h; 6 mL of graphene oxide slurry (10 mg / mL) was diluted to 1 mg / mL to obtain solution B, and 60 mL of solution A was mixed with the same volume of solution B, stirred at room temperature for 1 h, vacuum filtered after the reaction was completed, and dried at 60°C for 12 h to obtain the CHNs@graphene oxide film.

[0060] (2) Preparation of HKUST-1@graphene oxide film: the dried CHNs@graphene oxide film in step (1) was completely immersed in a 10 mM uniform tribenzoic acid (H3BTC) solution at room temperature for 12 h, washed, and dried at 60°C for 24 h to obtain the HKUST-1@graphene oxide film.

[0061] (3) Preparation of CuNi-LDH@graphene oxide film: the dried HKUST-1@graphene oxide film in step (2) was completely immersed in a polytetrafluoroethylene-lined autoclave containing a nickel nitrate solution, the solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol, and the mass ratio of the nickel nitrate, deionized water and anhydrous ethanol was 0.1:20:7.9, the reaction was carried out at 80°C for 2 h, the product was washed and dried at 60°C for 24 h to obtain the CuNi-LDH@graphene oxide film.

[0062] ​(4) Preparation of flexible CuNi-P@graphene lithium-ion battery film: The dried CuNi-LDH@graphene oxide film in step (3) was mixed with NaH2PO2 at a mass ratio of 1:5. Under N2 atmosphere, the temperature was increased to 400℃ at a rate of 2℃ / min, and then reacted at 400℃ for 2h to obtain flexible CuNi-P@graphene lithium-ion battery film.

[0063] Lithium-ion button batteries were prepared using the flexible CuNi-P@graphene lithium-ion battery film prepared in Example 3 as the negative electrode material. The results were obtained at different rate (0.1 A·g) -1 0.5 A·g -1 1 A·g -1 2 A·g -1 and 0.1 A·g -1 The cyclic performance graph is as follows: Figure 7 As shown; it is at 0.1 A·g -1 0.5 A·g -1 1 A·g -1 2 A·g -1 The capacity remained at 711.3 mAh·g at the specified current density. -1 456.5 mAh·g -1 376.5 mAh·g -1 and 289.3 mAh·g -1 When the current density recovers to 0.1 A·g -1 At that time, the capacity of the film was 674.8 mAh·g. -1 It reached 94.9% of the original level, which is basically restored to the original level, indicating that it has good recoverability.

[0064] Example 4: A method for preparing a flexible CuNi-P@graphene lithium-ion battery film

[0065] (1) Preparation of CHNs@graphene oxide membrane: Take 100 mL of Cu(NO3)2·3H2O (2 mM) solution and 100 mL of AE (0.7 mM) solution and mix them evenly. After aging at room temperature for 24 h, solution A is obtained. Take 6 mL of graphene oxide slurry (10 mg / mL) and dilute it to 1 mg / mL solution B. Take 60 mL of solution A and mix it with the same volume of solution B. Stir at room temperature for 1 hour. After the reaction is completed, filter under vacuum and dry at 60℃ for 12 hours to obtain CHNs@graphene oxide membrane.

[0066] (2) Preparation of HKUST-1@graphene oxide membrane: After step (1), the dried CHNs@graphene oxide membrane was completely immersed in a 10 mM tribenzoic acid (H3BTC) solution for 24 h at room temperature, washed, and dried at 60℃ for 24 h to obtain HKUST-1@graphene oxide membrane.

[0067] (3) Preparation of CuNi-LDH@graphene oxide film: The HKUST-1@graphene oxide film dried in step (2) was completely immersed in a polytetrafluoroethylene-lined autoclave containing nickel nitrate solution. The solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol. The mass ratio of nickel nitrate, deionized water and anhydrous ethanol was 0.1:20:7.9. The reaction was carried out at 60℃ for 2 h. After washing and drying at 60℃ for 24 h, CuNi-LDH@graphene oxide film was obtained.

[0068] (4) Preparation of flexible CuNi-P@graphene lithium-ion battery film: The dried CuNi-LDH@graphene oxide film in step (3) was mixed with NaH2PO2 at a mass ratio of 1:5. Under N2 atmosphere, the temperature was increased to 400℃ at a rate of 2℃ / min, and then reacted at 400℃ for 2h to obtain flexible CuNi-P@graphene lithium-ion battery film.

[0069] Lithium-ion button batteries were prepared using the flexible CuNi-P@graphene lithium-ion battery film prepared in Example 4 as the negative electrode material. The results were obtained at different rate (0.1 A·g) -1 0.5 A·g -1 1 A·g -1 2 A·g -1 and 0.1 A·g -1 The cyclic performance graph is as follows: Figure 8 As shown; it is at 0.1 A·g -1 0.5 A·g -1 1 A·g -1 2 A·g -1 The capacity remained at 561.2 mAh·g at the specified current density. -1 280.4 mAh·g -1 188.6 mAh·g -1 and 90.5 mAh·g -1 When the current density recovers to 0.1 A·g -1 At that time, the capacity of the film was 433.7 mAh·g. -1 It reached 77.3% of the original level, indicating that it has good recoverability.

[0070] Example 5: A method for preparing a flexible CuNi-P@graphene lithium-ion battery film

[0071] (1) Preparation of CHNs@ graphene oxide film: 100 mL Cu(NO3)2·3H2O (2 mM) solution and 100 mL AE (0.7 mM) solution were mixed uniformly, and solution A was obtained after aging at room temperature for 24 h; 6 mL graphene oxide slurry (10 mg / mL) was diluted to 1 mg / mL to obtain solution B; 60 mL of solution A was mixed with the same volume of solution B, and stirred at room temperature for 1 h; after the reaction was completed, vacuum filtration was performed, and the CHNs@ graphene oxide film was obtained after drying at 60℃ for 12 h.

[0072] (2) Preparation of HKUST-1@ graphene oxide film: the dried CHNs@ graphene oxide film in step (1) was completely immersed in a 10 mM uniform tribenzoic acid (H3BTC) solution at room temperature for 24 h, washed, and dried at 60℃ for 24 h to obtain the HKUST-1@ graphene oxide film.

[0073] (3) Preparation of CuNi-LDH@ graphene oxide film: the dried HKUST-1@ graphene oxide film in step (2) was completely immersed in a polytetrafluoroethylene-lined autoclave containing a nickel nitrate solution, the solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol, and the mass ratio of nickel nitrate, deionized water and anhydrous ethanol was 0.1:20:7.9; the reaction was carried out at 70℃ for 2 h, and the CuNi-LDH@ graphene oxide film was obtained after washing and drying at 60℃ for 24 h.

[0074] (4) Preparation of flexible CuNi-P@ graphene lithium ion battery film: the dried CuNi-LDH@ graphene oxide film in step (3) was mixed with NaH2PO2 at a mass ratio of 1:5, heated to 400℃ at a rate of 2℃ / min under N2 atmosphere, and then reacted at 400℃ for 2 h to obtain the flexible CuNi-P@ graphene lithium ion battery film.

[0075] The flexible CuNi-P@ graphene lithium ion battery film prepared in Example 5 was used as a negative electrode material to prepare a lithium ion button cell, and the cycle performance diagram thereof at different rates (0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 and 0.1 A·g -1 ) is shown in Figure 9 ; and the capacity thereof at 0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 current density was 718.3 mAh·g-1 , 505.5 mAh·g -1 , 400.2 mAh·g -1 and 308.2 mAh·g -1 When the current density returned to 0.1 A·g -1 , the capacity of the film was 704.8 mAh·g -1 , reaching 98.1% of the original level and basically returning to the original level, indicating that it had good recoverability.

[0076] Example 6 A preparation method of a flexible CuNi-P@graphene lithium ion battery film

[0077] (1) Preparation of CHNs@graphene oxide film: 100 mL of Cu(NO3)2·3H2O (2 mM) solution and 100 mL of AE (0.7 mM) solution were mixed uniformly, and solution A was obtained after aging at room temperature for 24 h; 6 mL of graphene oxide slurry (10 mg / mL) was diluted to a solution B of 1 mg / mL, and 60 mL of solution A was mixed with the same volume of solution B, stirred at room temperature for 1 h, vacuum filtration after the reaction was completed, and dried at 60°C for 12 h to obtain the CHNs@graphene oxide film.

[0078] (2) Preparation of HKUST-1@graphene oxide film: the dried CHNs@graphene oxide film in step (1) was soaked in a 10 mM uniform tribenzoic acid (H3BTC) solution at room temperature for 24 h, washed, and dried at 60°C for 24 h to obtain the HKUST-1@graphene oxide film.

[0079] (3) Preparation of CuNi-LDH@graphene oxide film: the dried HKUST-1@graphene oxide film in step (2) was transferred to a polytetrafluoroethylene-lined autoclave containing a nickel nitrate solution, the solvent of the nickel nitrate solution in the autoclave was deionized water and anhydrous ethanol, and the mass ratio of the nickel nitrate, deionized water, and anhydrous ethanol was 0.1:20:7.9, the reaction was carried out at 80°C for 1 h, the product was washed and dried at 60°C for 24 h to obtain the CuNi-LDH@graphene oxide film.

[0080] (4) Preparation of flexible CuNi-P@graphene lithium ion battery film: the dried CuNi-LDH@graphene oxide film in step (3) was mixed with NaH2PO2 at a mass ratio of 1:5, heated to 400°C at a speed of 2°C / min under N2 atmosphere, and then reacted at 400°C for 2 h to obtain the flexible CuNi-P@graphene lithium ion battery film.

[0081] The flexible CuNi-P@graphene lithium ion battery thin film prepared in Example 6 was used as a negative electrode material to prepare a lithium ion button cell, and the cycle performance diagram thereof at different rates (0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 and 0.1 A·g -1 ) is shown in Figure 10 ; the capacity thereof was maintained at 728.2 mAh·g -1 , 509.5 mAh·g -1 , 396.5 mAh·g -1 and 303.3 mAh·g -1 at 0.1 A·g -1 , 0.5 A·g -1 , 1 A·g -1 , 2 A·g -1 current density, respectively. When the current density returned to 0.1 A·g -1 , the capacity of the thin film was 605.1 mAh·g -1 , reaching 83.1% of the original level, indicating that it had good recoverability.

Claims

1. A method for preparing a flexible CuNi-P@graphene lithium-ion battery thin film, characterized in that: The preparation method includes preparing CHNs@graphene oxide film, preparing HKUST-1@graphene oxide film, preparing CuNi-LDH@graphene oxide film, and obtaining flexible CuNi-P@graphene lithium-ion battery film. The method for preparing CHNs@graphene oxide membrane is as follows: copper nitrate solution and ethanolamine solution are mixed evenly and aged at room temperature for 23-25 ​​hours to obtain solution A; graphene oxide slurry is diluted to 0.8-1.2 mg / mL to obtain solution B; solution A and solution B are mixed at a volume ratio of 1:0.9-1.1 and stirred for 0.8-1.2 hours; then, the mixture is vacuum filtered and dried to obtain CHNs@graphene oxide membrane. The concentration of the copper nitrate solution is 1.8-2.2 mM, and the concentration of the ethanolamine solution is 0.6-0.8 mM; the volume ratio of the copper nitrate solution to the ethanolamine solution is 1:0.9-1.

1. The method for preparing HKUST-1@graphene oxide film is to completely immerse the CHNs@graphene oxide film in a 9-11mM tribenzoic acid solution at room temperature for 12-24 hours, and then wash and dry to obtain the HKUST-1@graphene oxide film. The method for preparing CuNi-LDH@graphene oxide film is to completely immerse HKUST-1@graphene oxide film in nickel nitrate solution, react at 60-80℃ for 1-2 hours, and obtain CuNi-LDH@graphene oxide film after washing and drying. The solvent for the nickel nitrate solution is deionized water and anhydrous ethanol, wherein the mass ratio of nickel nitrate to deionized water and anhydrous ethanol is 0.05-0.1:20:7.8-8. The flexible CuNi-P@graphene lithium-ion battery film was prepared by mixing CuNi-LDH@graphene oxide film with NaH2PO2 at a mass ratio of 1:4.8-5.2, heating to 395-405℃ at a rate of 1.8-2.2℃ / min under N2 atmosphere, and reacting at this temperature for 1.9-2.1h to obtain the flexible CuNi-P@graphene lithium-ion battery film.

2. The application of the flexible CuNi-P@graphene lithium-ion battery film prepared by the method of claim 1, characterized in that: The flexible CuNi-P@graphene lithium-ion battery film is used as a negative electrode material for assembling lithium-ion batteries.

Images