A supercapacitor based on hybrid MOFs electrode film and its preparation method

Abstract

The present invention belongs to the field of electrochemical energy storage and discloses a supercapacitor based on a hybrid MOFs electrode film and a preparation method thereof. The preparation method comprises the following steps: mixing two MOFs materials, Ni3(HITP)2 and Cu2(OHPTP), and preparing the hybrid MOFs electrode film under the action of a binder, wherein the Ni3(HITP)2 and Cu2(OHPTP) have different pore sizes; using an ionic liquid compatible with the Ni3(HITP)2 and Cu2(OHPTP) sizes as an electrolyte; and encapsulating the hybrid MOFs electrode film with the electrolyte to obtain a supercapacitor. By mixing two MOFs materials with different pore sizes, Ni3(HITP)2 and Cu2(OHPTP), and matching them with the ionic liquid electrolyte, the MOFs-based supercapacitor produced by the present invention can achieve comprehensive improvements in capacitance performance and charging speed.

Description

Technical Field

[0001] The present invention belongs to the technical field related to electrochemical energy storage, and more specifically, relates to a supercapacitor based on a hybrid MOFs electrode film and a preparation method thereof. Background Art

[0002] Metal-Organic Frameworks (MOFs) refer to a class of crystalline materials that are interconnected by coordination bonds between metal ions or metal ion clusters and organic ligands to form a spatially ordered arrangement. Due to its many advantages such as high porosity, adjustable structure, large specific surface area, and functional doping, MOFs have received extensive research attention and practical applications in many fields such as gas adsorption or separation, catalytic reactions, biomedical applications, and chemical sensing. With the continuous and in-depth exploration of the conductive mechanism of MOFs materials, a series of conductive MOFs with high electrical conductivity have been successfully prepared, which makes this type of material show great development potential and broad application prospects in the field of electrochemical energy storage.

[0003] In recent years, the rise of conductive MOFs (MOFs), formed by the coordination of multiple organic ligands and transition metal ions, has led to the development of supercapacitors based on these materials. Studies have shown that within the micropore region (less than 2 nm), the capacitance and charging rate of electrodes exhibit a damped oscillation with pore size. However, reported conductive MOF supercapacitors have all suffered from low capacitance and slow charging rates.

[0004] Therefore, there is an urgent need to solve the technical problems of insufficient capacitance performance and charging speed of conductive MOFs-based supercapacitors. Summary of the Invention

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a supercapacitor based on a hybrid MOFs electrode membrane and a preparation method thereof. The supercapacitor is formed by mixing two MOFs materials with different pore sizes, Ni3(HITP)2 and Cu2(OHPTP), with a multi-porous electrode membrane composed of a binder, and selecting an ionic liquid electrolyte that is compatible with the two pore sizes, thereby solving the technical problems of insufficient capacitance performance and charging speed of conductive MOFs-based supercapacitors.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a method for preparing a supercapacitor based on a hybrid MOFs electrode film is provided, comprising the following steps: mixing two MOFs materials, Ni3(HITP)2 and Cu2(OHPTP), and preparing a hybrid MOFs electrode film under the action of a binder, wherein the pore sizes of the Ni3(HITP)2 and the Cu2(OHPTP) are different; using an ionic liquid that is compatible with the sizes of the Ni3(HITP)2 and the Cu2(OHPTP) as an electrolyte; and encapsulating the hybrid MOFs electrode film and the electrolyte to obtain a supercapacitor.

[0007] Preferably, the ratio of the pore size of the Ni3(HITP)2 to the size of the ions or ion clusters in the electrolyte is 1:2, 3:2 or 5:2, and the ratio of the pore size of the Cu2(OHPTP) to the size of the ions or ion clusters in the electrolyte is 1:2, 3:2 or 5:2.

[0008] Preferably, the mass ratio of the Ni3(HITP)2 and the Cu2(OHPTP) is 1:4 to 4:1.

[0009] Preferably, two MOFs materials, Ni3(HITP)2 and Cu2(OHPTP), are mixed, evenly mixed to form agglomerates under the action of a binder, and rolled to obtain a mixed MOFs electrode film; wherein the thickness of the mixed MOFs electrode film is 100 to 200 μm.

[0010] Preferably, the electrolyte is one or more of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and tetramethylammonium tetrafluoroborate.

[0011] Preferably, the electrolyte is a mixture of 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

[0012] Preferably, the binder is polytetrafluoroethylene or polyvinylidene fluoride.

[0013] Preferably, the process of preparing the hybrid MOFs electrode film further comprises: adjusting the bonding state by adding a diluent after adding the binder;

[0014] Wherein, when the binder is polytetrafluoroethylene, the diluent is anhydrous ethanol; when the binder is polyvinylidene fluoride, the diluent is N-methylpyrrolidone.

[0015] Preferably, the hybrid MOFs electrode membrane and the electrolyte are packaged to obtain a supercapacitor, specifically comprising: placing a diaphragm between two hybrid MOFs electrode membranes, filling the electrolyte, and packaging to obtain a supercapacitor.

[0016] According to another aspect of the present invention, a supercapacitor prepared according to the method for preparing a supercapacitor based on a hybrid MOFs electrode film provided in one aspect of the present invention is provided.

[0017] In general, the above technical solutions conceived by the present invention have the following technical advantages compared with the existing technology:

[0018] The present invention combines two MOFs materials with different pore sizes, Ni3(HITP)2 and Cu2(OHPTP), and adapts them to an ionic liquid electrolyte to produce a MOFs-based supercapacitor that achieves comprehensive improvements in capacitance performance and charging speed. This is because the pore size of the conductive MOF determines its pore structure, which in turn affects its capacitance performance. However, the presence of only a single pore size makes it difficult to adapt to the ion size of the mixed ionic liquid electrolyte, resulting in a limited charging speed. The present invention combines two MOFs materials with different pore sizes, Ni3(HITP)2 and Cu2(OHPTP), and prepares a mixed MOFs electrode membrane under the action of a binder, which can maximize compatibility with the ionic liquid electrolyte. The ions or ion clusters in the selected ionic liquid electrolyte are compatible with the two different pore sizes of Ni3(HITP)2 and Cu2(OHPTP), thereby achieving a comprehensive improvement in capacitance performance and charging speed performance of the MOFs-based supercapacitor of the present invention.

[0019] Preferably, when the mixed mass ratio of Ni3(HITP)2 and Cu2(OHPTP) in the hybrid electrode membrane is 1:4 to 4:1, it can be adapted to ionic liquid electrolytes commonly used in supercapacitors, such as one or more of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and tetramethylammonium tetrafluoroborate (TMABF4). The above two MOFs, of which Ni3(HITP)2 has a larger pore size of 1.54nm and Cu2(OHPTP) has a smaller pore size of 1.1nm, both meet the relationship of half-integer multiples of the size of ions or ion clusters in the ionic electrolyte, thereby allowing the ionic liquid electrolytes commonly used in supercapacitors to enter the pores of the corresponding MOFs in a more orderly manner, thereby producing a higher specific capacitance value and significantly improving the charging speed.

[0020] Preferably, when the mass ratio of Ni3(HITP)2 and Cu2(OHPTP) in the mixed MOFs electrode membrane is 1:4 to 4:1, and the electrolyte is 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI) and a mixture thereof, the supercapacitor of the mixed MOFs electrode membrane in the present invention has the greatest improvement in charging speed compared with the supercapacitor of a single electrode membrane in a mixed ionic liquid electrolyte system with a volume ratio of 2:3, which is 2.4 times that of the pure Ni3(HITP)2 electrode membrane supercapacitor; at the same time, in this electrolyte system, the capacitance performance is improved the most, and the specific capacitance value of the pure Ni3(HITP)2 electrode membrane supercapacitor is increased by 13.2%. This is due to the larger ion size of TFSI - They tend to enter the pores of Cu2(OHPTP) with a pore size of 1.1nm, causing them to accumulate more densely in the pores, while larger anion clusters tend to enter the pores of Ni3(HITP)2 with a pore size of 1.54nm, resulting in a higher specific capacitance value; at the same time, since single ions and ion clusters can enter two different pores in an orderly manner respectively, the time for ion transmission in the pores is effectively reduced, significantly improving the charging speed.

[0021] Preferably, the process of preparing the hybrid MOFs electrode membrane also includes: adjusting the oscillation and ultrasonic time, and after adding the binder, adjusting the bonding state by adding a diluent so that the MOFs material is evenly mixed and distributed in the binder, thereby improving the uniformity of the supercapacitor pore structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the adsorption curve of Ni3(HITP)2 and its pore size distribution diagram according to the present invention, where the inset is the pore size distribution diagram.

[0023] Figure 2 The adsorption curve of Cu2(OHPTP) and its pore size distribution diagram are shown in the figure, where the inset is the pore size distribution diagram.

[0024] Figure 3 These are structural diagrams of two MOFs materials used as examples in the present invention. The left diagram is the structural diagram of Ni3(HITP)2, and the right diagram is the structural diagram of Cu2(OHPTP).

[0025] Figure 4 This is a scanning electron microscope image of the mixed electrode film prepared by Ni3(HITP)2 and Cu2(OHPTP) in the present invention with a mass ratio of 4:1 and its element distribution test diagram, wherein the inset is the element distribution test diagram.

[0026] Figure 5A diagram of a supercapacitor prototype obtained by encapsulating a mixed electrode film of Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 1:4 in Example 1 of the present invention and a mixed electrolyte of EMIMBF4 and EMIMTFSI in a volume ratio of 2:3, and a photo of the LED lamp lighting up after charging, wherein the inset is a photo of the LED lamp lighting up after charging.

[0027] Figure 6 The capacitive performance of the supercapacitor with mixed MOFs electrode membrane and the supercapacitor with single electrode membrane as examples of the present invention.

[0028] Figure 7 The charging time of the supercapacitor with mixed MOFs electrode membrane and the supercapacitor with single electrode membrane as examples of the present invention.

[0029] Figure 8 This is a scanning electron microscope image of the mixed electrode film prepared by Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 2:3 in the present invention and its element distribution test diagram, wherein the inset is the element distribution test diagram.

[0030] Figure 9 This is a scanning electron microscope image of the mixed electrode film prepared by Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 1:4 in the present invention and its element distribution test diagram, wherein the inset is the element distribution test diagram. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0032] The HITP in the Ni3(HITP)2 of the present invention is 2,3,6,7,10,11-hexamidintriphenylene. The preparation method of Ni3(HITP)2 is as follows:

[0033] (1) Add 120 mL of 2.33 mmol / L nickel acetate solution (solvent is a mixture of DMA and DMF, volume ratio 1:1) to a 500 mL beaker and preheat to 65 °C;

[0034] (2) Add 80 mL of 2 mol / L sodium acetate aqueous solution into the beaker containing the nickel acetate solution in step (1) and continue heating to 65°C;

[0035] (3) Add 30 mL of 2,3,6,7,10,11-hexamidotriphenylene hydrochloride (HATP·6HCl) aqueous solution to the beaker of the mixed solution in step (2), and react the mixed solution at 65°C for 4 h;

[0036] (4) After the reaction is completed and the solution is cooled to room temperature, the supernatant is removed and the remaining precipitate is centrifuged and filtered to obtain Ni3(HITP)2;

[0037] (5) The solid was then washed three times with deionized water and methanol, respectively. The single washing process was as follows: the solid was transferred to a beaker, 180 mL of the washing solvent was added thereto, and after stirring at room temperature for 40 min, the filter cake was obtained by vacuum filtration;

[0038] (6) The filter cake was placed in a vacuum drying oven and dried at room temperature for 24 h to obtain the clean final product Ni3(HITP)2.

[0039] like Figure 1 As shown, the adsorption diagram of Ni3(HITP)2 material shows that it exhibits obvious micropore adsorption characteristics, and the pore size distribution curve shows that it has a single pore with a pore size of 1.54 nm.

[0040] The OHPTP in the Cu2(OHPTP) of the present invention is 2,3,6,7,11,12,15,16-octahydroxyphenanthro[9,10:b]triphenylene. The preparation method of Cu2(OHPTP) is as follows:

[0041] (1) Add 12 mg of OHPTP powder, 9.6 mg of copper acetate monohydrate, and 2.3 mL of deionized water to a 10 mL reactor.

[0042] (2) ultrasonically treating the above solution for 10 min until the suspension is uniformly mixed;

[0043] (3) Add 1 mL of DMF (N,N-dimethylformamide) dropwise to the reactor and continue ultrasonic treatment for 5 min;

[0044] (4) After sealing the reactor, place it in an oven preheated to 85°C and react for 12 to 16 hours;

[0045] (5) After the reaction is completed, the reactor is cooled to room temperature, and the reaction solution is centrifuged and filtered, and then washed twice with 100 mL of deionized water and 20 mL of acetone respectively, and the washing is carried out by vacuum filtration;

[0046] (6) The filter cake was placed in a vacuum drying oven and dried at room temperature for 24 h to obtain the clean final product Cu2(OHPTP).

[0047] like Figure 2As shown, the adsorption diagram of Cu2(OHPTP) material shows that it exhibits obvious microporous adsorption characteristics, and the pore size distribution curve shows that it has a single pore with a pore size of 1.1 nm.

[0048] According to the present invention, the raw materials used in the hybrid MOFs electrode membrane provided are Ni3(HITP)2 and Cu2(OHPTP), the conductive MOF with a larger pore size adopts Ni3(HITP)2 (pore size of 1.54nm), and the conductive MOF with a smaller pore size adopts Cu2(OHPTP) (pore size of 1.10nm). The structural diagrams of the two MOFs are shown in FIG. Figure 3 shown.

[0049] A method for preparing a supercapacitor based on a hybrid MOFs electrode film is provided below. The specific steps of the preparation are as follows:

[0050] (1) Weigh 10-40 mg of Ni3(HITP)2 powder and 10-40 mg of Cu2(OHPTP) powder into a 5 mL beaker;

[0051] (2) Place the beaker on a turbine shaker and shake until the two powders are evenly mixed;

[0052] (3) Add a diluent to the beaker and sonicate the mixture, followed by adding a binder compatible with the diluent. In the present invention, the binder is 6.2 μL of a 60% (mass fraction) polytetrafluoroethylene concentrate, with 0.5 to 2 mL of anhydrous ethanol as the diluent, which is dispersed between the MOF particles to connect the particles and form a film. Alternatively, polyvinylidene fluoride can be used as the binder, with N-methylpyrrolidone as the diluent.

[0053] (4) Physically stirring the mixture in the beaker until it forms a clumping mass;

[0054] (5) placing the mass on a roller mill and rolling it, repeating this step 2 to 3 times to form a mixed MOFs electrode membrane with a thickness of 100 to 200 μm;

[0055] (6) placing the mixed MOFs electrode membrane in a vacuum drying oven and drying until the liquid is completely volatilized, thereby obtaining a multi-pore mixed MOFs electrode membrane;

[0056] (7) preparing an electrolyte; the electrolyte described in the present invention is tetramethylammonium tetrafluoroborate (TMABF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI), preferably EMIMBF4 and EMIMTFSI are mixed in any volume fraction to prepare an ionic liquid mixture electrolyte, or one of EMIMBF4 and EMIMTFSI is used as a single electrolyte;

[0057] (8) Use a punch to cut the electrode film into 10 mm discs and the Celgard 3501 diaphragm into 18 mm discs; place the diaphragm between two hybrid MOFs electrode films, fill them with the above-mentioned electrolyte, and encapsulate them to obtain a supercapacitor based on the hybrid MOFs electrode film.

[0058] The following are specific embodiments:

[0059] Example 1:

[0060] (1) Weigh 40 mg of Ni3(HITP)2 powder and 10 mg of Cu2(OHPTP) powder into a 5 mL beaker;

[0061] (2) Place the beaker on a turbine shaker and shake for 10 minutes to mix the two powders evenly;

[0062] (3) 2 mL of ethanol was added to the beaker and the mixture was sonicated for 10 min, followed by the addition of 6.2 μL of 60% polytetrafluoroethylene concentrate;

[0063] (4) Physically stirring the mixture in the beaker until it forms a clumping mass;

[0064] (5) The pellets were placed on a roller mill and rolled, and the process was repeated 2 to 3 times to form a mixed MOFs electrode film with a thickness of 150 μm.

[0065] (6) placing the mixed MOFs electrode film in a vacuum drying oven and drying it for 24 hours to obtain a porous mixed MOFs electrode film;

[0066] (7) EMIMBF4 and EMIMTFSI were mixed in volume ratios of 4:1, 3:2, 2:3, and 1:4 to prepare ionic liquid mixture electrolytes, and EMIMBF4 and EMIMTFSI were used as single ionic liquids as electrolytes for a total of 6 experiments with the above electrode film preparation;

[0067] (8) Use a punch to cut the electrode film into 10 mm discs and the Celgard 3501 diaphragm into 18 mm discs; place the diaphragm between two hybrid MOFs electrode films, fill them with the above-mentioned electrolyte, and encapsulate them to obtain a supercapacitor based on the hybrid MOFs electrode film.

[0068] Comparative Example 1:

[0069] The difference from Example 1 is that the electrode material selected is 50 mg of Ni3(HITP)2 powder.

[0070] Comparative Example 2:

[0071] The difference from Example 1 is that the electrode material selected is 50 mg of Cu2(OHPTP) powder.

[0072] Figure 4 The scanning electron microscope image and element distribution of the electrode film prepared by mixing Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 4:1 in Example 1 show that its particle distribution is very uniform.

[0073] Figure 5 This is a picture of a supercapacitor prototype prepared by the method of Example 1 and a photo of it successfully lighting an LED lamp after charging; the mixed MOFs electrode film is prepared by mixing Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 4:1, and the mixed electrolyte is prepared by mixing EMIMBF4 and EMIMTFSI in a volume fraction ratio of 2:3.

[0074] Figure 6 and Figure 7 The performance of supercapacitors prepared by encapsulating the porous mixed MOFs electrode membrane prepared by mixing Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 4:1 in Example 1 with 6 groups of different electrolytes, as well as the performance of supercapacitors prepared by encapsulating Ni3(HITP)2 as a single pore size electrode membrane with 6 groups of different electrolytes in Comparative Example 1.

[0075] from Figure 6 and Figure 7It can be seen that the volume fractions of 0% and 100% correspond to the single ionic liquids EMIMBF4 and EMIMTFSI, respectively. For the hybrid MOFs electrode membrane prepared by mixing Ni3(HITP)2 and Cu2(OHPTP) at a mass ratio of 4:1, the supercapacitor of the hybrid MOFs electrode membrane has the greatest improvement in capacitance performance compared to the supercapacitor of the single electrode membrane in the mixed ionic liquid electrolyte system with a volume ratio of 2:3, with the specific capacitance value increasing by 13.2% relative to the pure Ni3(HITP)2 single electrode membrane supercapacitor. At the same time, the charging speed is also improved the most in this system, which is 2.4 times that of the pure Ni3(HITP)2 electrode membrane supercapacitor.

[0076] Example 2:

[0077] (1) Weigh 20 mg of Ni3(HITP)2 powder and 30 mg of Cu2(OHPTP) powder into a 5 mL beaker;

[0078] (2) Place the beaker on a turbine shaker and shake for 8 minutes to mix the two powders evenly;

[0079] (3) 1 mL of ethanol was added to the beaker and the mixture was sonicated for 8 min, followed by the addition of 6.2 μL of 60% polytetrafluoroethylene concentrate;

[0080] (4) Physically stirring the mixture in the beaker until it forms a clumping mass;

[0081] (5) The pellet was placed on a roller mill and rolled to form a mixed MOFs electrode membrane with a thickness of 150 μm. This step was repeated twice.

[0082] (6) placing the mixed MOFs electrode film in a vacuum drying oven and drying it for 24 hours to obtain a porous mixed MOFs electrode film;

[0083] (7) preparing an ionic liquid mixture electrolyte by mixing 40% by volume of ionic liquid EMIMBF4 and 60% by volume of EMIMTFSI;

[0084] (8) Use a punch to cut the electrode film into 10 mm discs and the Celgard 3501 diaphragm into 18 mm discs; place the diaphragm between two hybrid MOFs electrode films, fill them with the above-mentioned electrolyte, and encapsulate them to obtain a supercapacitor based on the hybrid MOFs electrode film.

[0085] Figure 8 Shown are the scanning electron microscope images and element distribution of the electrode film prepared with Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 2:3 in Example 2. It can be seen that the particle distribution of the mixed MOFs electrode film is very uniform.

[0086] Example 3:

[0087] (1) Weigh 10 mg of Ni3(HITP)2 powder and 40 mg of Cu2(OHPTP) powder into a 5 mL beaker;

[0088] (2) Place the beaker on a turbine shaker and shake for 6 minutes to mix the two powders evenly;

[0089] (3) 0.5 mL of ethanol was added to the beaker and the mixture was sonicated for 6 min, followed by the addition of 6.2 μL of 60% polytetrafluoroethylene concentrate;

[0090] (4) Physically stirring the mixture in the beaker until it forms a clumping mass;

[0091] (5) The pellet was placed on a roller mill and rolled to form a mixed MOFs electrode membrane with a thickness of 150 μm. This step was repeated three times.

[0092] (6) placing the mixed MOFs electrode membrane in a vacuum drying oven and drying it for 24 hours to obtain a mixed MOFs electrode membrane with multiple pore sizes;

[0093] (7) Mixing 20% ​​by volume of ionic liquid EMIMBF4 and 80% by volume of EMIMTFSI to prepare an ionic liquid mixture electrolyte;

[0094] (8) Use a punch to cut the electrode film into 10 mm discs and the Celgard 3501 diaphragm into 18 mm discs; place the diaphragm between two hybrid MOFs electrode films, fill them with the above-mentioned electrolyte, and encapsulate them to obtain a supercapacitor based on the hybrid MOFs electrode film.

[0095] Figure 9 Shown are the scanning electron microscope images and element distribution of the electrode film prepared with Ni3(HITP)2 and Cu2(OHPTP) in a mass ratio of 1:4 in Example 3. It can be seen that the particle distribution of the mixed MOFs electrode film is very uniform.

[0096] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such modifications and variations fall within the scope of the present invention and its equivalents, the present invention is intended to encompass such modifications and variations. The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention and are not intended to limit the scope of protection. Any equivalent substitutions or modifications made by those skilled in the art based on the present invention are also within the scope of protection of the present invention.

Claims

1. A method for preparing a supercapacitor based on a hybrid MOFs electrode film, characterized in that: The steps include: Two MOFs materials, Ni3(HITP)2 and Cu2(OHPTP), are mixed to prepare a mixed MOFs electrode membrane under the action of a binder, wherein the pore sizes of the Ni3(HITP)2 and the Cu2(OHPTP) are different; an ionic liquid that is compatible with the pore size of the Ni3(HITP)2 and the pore size of the Cu2(OHPTP) is used as an electrolyte, wherein the ratio of the pore size of the Ni3(HITP)2 to the size of the ions or ion clusters in the electrolyte is 3:2 or 5:2, and the ratio of the pore size of the Cu2(OHPTP) to the size of the ions or ion clusters in the electrolyte is 3:2 or 5:2; and the mixed MOFs electrode membrane and the electrolyte are encapsulated to obtain a supercapacitor.

2. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 1, characterized in that: The mass ratio of the Ni3(HITP)2 to the Cu2(OHPTP) is 1:4~4:

1.

3. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 1, characterized in that: During the preparation of the hybrid MOFs electrode film: Two MOFs materials, Ni3(HITP)2 and Cu2(OHPTP), are mixed, uniformly mixed under the action of a binder until they form a mass, and then rolled to produce a mixed MOFs electrode film; wherein the thickness of the mixed MOFs electrode film is 100~200 μm.

4. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 1, characterized in that: The electrolyte is one or more of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and tetramethylammonium tetrafluoroborate.

5. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 4, characterized in that: The electrolyte is formed by mixing 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

6. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 1, characterized in that: The binder is polytetrafluoroethylene or polyvinylidene fluoride.

7. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 6, characterized in that: The process of preparing the hybrid MOFs electrode film further includes: adjusting the bonding state by adding a diluent after adding the binder; Wherein, when the binder is polytetrafluoroethylene, the diluent is anhydrous ethanol; when the binder is polyvinylidene fluoride, the diluent is N-methylpyrrolidone.

8. The method for preparing a supercapacitor based on a hybrid MOFs electrode film according to claim 1, characterized in that: Encapsulating the mixed MOFs electrode film and the electrolyte to obtain a supercapacitor specifically comprises: The separator is placed between two mixed MOFs electrode films, filled with the electrolyte, and encapsulated to obtain a supercapacitor.

9. A supercapacitor prepared according to the method for preparing a supercapacitor based on a hybrid MOFs electrode film according to any one of claims 1 to 8.

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