Physically cross-linked electrolytic ionomer, composite membrane electrode prepared therefrom, and preparation method thereof.

Abstract

The application discloses a kind of physical crosslinking electrically controlled ion glue, composite membrane electrode and preparation method prepared thereby.Polyvinylidene fluoride binder is added to N-methylpyrrolidone solution, and is dissolved by being stirred sufficiently to prepare polyvinylidene fluoride binder solution;Slowly add polyacrylic acid binder with ion transfer function in the above binder solution;Two kinds of binders are blended by heating to make them produce physical crosslinking, i.e., to prepare stable and uniform physical crosslinking electrically controlled ion glue.The physical crosslinking electrically controlled ion glue is used to prepare high ionic conductive composite membrane electrode, compared with traditional polyvinylidene fluoride binder, hydrogen proton on the carboxylic acid functional group of electrically controlled ion glue can occur ion exchange reaction with lithium ion in solution, promote the transfer of lithium ion on the interface of composite membrane electrode, so as to be beneficial to improve the separation performance of lithium ion of composite membrane electrode.

Description

Technical Field

[0001] This invention relates to a physically cross-linked electro-controlled ionic adhesive, a composite membrane electrode prepared therefrom, and a preparation method thereof, belonging to the field of adhesive technology. Background Technology

[0002] Lithium, as one of the most important energy elements of the 21st century, is widely used in ceramics, lubricants, the nuclear industry, and lithium batteries. With the widespread adoption of lithium batteries in electronic communication equipment and electric vehicles, my country's demand for lithium resources will gradually increase in the future. Lithium resources on Earth are mainly distributed in lithium ores, seawater, and salt lake brines. However, the mining of solid lithium ores can easily cause serious damage to the ecological environment; the concentration of lithium ions in seawater is low, making extraction technology difficult. Therefore, extracting lithium ions from salt lake brines rich in lithium resources has broad industrial application prospects.

[0003] Methods for extracting lithium ions from salt lake brine mainly include adsorption / ion exchange, solvent extraction, precipitation, and membrane separation. Among these, adsorption has gained widespread attention in salt lake lithium extraction technology due to its high adsorption capacity and ideal lithium ion selectivity. However, the low adsorption rate and the need for acid washing regeneration of the adsorbent in adsorption methods can easily cause secondary pollution to the environment, limiting the further development of this method in industrial applications.

[0004] In recent years, electro-controlled ion exchange has attracted widespread attention due to its ability to improve lithium-ion capture rates under electric field drive and to effectively avoid secondary pollution by adjusting the oxidation / reduction state of the electro-controlled ion exchange composite membrane electrode to achieve target ion insertion / release. Electro-controlled ion exchange composite membrane electrodes are prepared by using binders to fix electroactive ion exchange functional materials and conductive additives onto a conductive current collector based on physical or chemical interactions. To achieve ideal electro-controlled ion exchange performance, conductive ion-transfer adhesives with ion-carrying capabilities are needed to prepare composite membrane electrodes with high ion conductivity. However, currently reported conductive ion-transfer adhesives can only transfer electrons and not ions. For example, Chinese Patent Publication No. CN103602269A, "Inorganic Conductive Ion-Gel and its Preparation Method," synthesizes conductive ion-transfer adhesives with high electron transfer but no ion transfer. To date, no synthesis method for specialized conductive ion-transfer adhesives required for electro-controlled ion exchange technology and the application of the prepared high ion conductivity composite membrane electrodes have been reported. Summary of the Invention

[0005] To address the issue of poor ion transfer properties in traditional adhesives, this invention provides a method for preparing physically cross-linked electrically controlled ion exchange adhesives required for electrically controlled ion exchange technology, and uses these physically cross-linked electrically controlled ion exchange adhesives to prepare composite membrane electrodes with high ion conductivity.

[0006] The present invention is based on the following concept: Polyvinylidene fluoride (PVDF) has been widely used in electrode binders due to its good electrochemical stability. However, PVDF binders have the disadvantage of poor ionic conductivity. In addition, PVDF binders also have weak bonding performance, which is mainly due to: (1) PVDF binders can only generate weak van der Waals forces between electrode constituent materials; (2) PVDF binders are usually mechanically mixed with electroactive materials and conductive additives in powder form first, and then the mixture is transferred to an N-methylpyrrolidone solution and stirred to prepare an electrode slurry. This may make it difficult for electroactive materials, conductive additives and PVDF binders to be fully dispersed, thereby affecting the bonding performance.

[0007] Based on the above considerations, this invention proposes to use electrochemically stable polyvinylidene fluoride (PVDF) as a support carrier and polyacrylic acid (PAC), which has ion-transfer capabilities, as a functional filler to prepare a specialized conductive ionic adhesive for electro-controlled ion exchange technology. Compared with single PVDF adhesives, the hydrogen protons on the carboxylic acid functional groups of this electro-controlled ion adhesive can undergo ion exchange reactions with lithium ions in solution, promoting lithium ion transfer at the composite membrane electrode interface, thereby effectively improving the ionic conductivity of the composite membrane electrode. This electro-controlled ion adhesive also exhibits superior adhesion properties. This is because the carboxylic acid groups in the polyacrylic acid of the electro-controlled ion adhesive can form hydrogen bonds with the hydroxyl groups on the surface of conductive additives and electroactive materials, thereby generating stronger adhesion between the electro-controlled ion adhesive and the conductive additives and electroactive materials. Furthermore, this invention first synthesizes a liquid physically cross-linked electro-controlled ion adhesive, and then adds the electroactive materials and conductive additives to the electro-controlled ion adhesive and prepares an electrode slurry through thorough stirring. This process allows the electroactive materials and conductive additives to be fully dispersed in the electro-controlled ion adhesive, thereby further improving the adhesion strength of the coating on the current collector.

[0008] This invention provides a method for preparing a physically crosslinked electrically controlled ionomer adhesive, comprising the following steps: adding polyvinylidene fluoride adhesive to an N-methylpyrrolidone solution and stirring thoroughly to dissolve it to obtain a polyvinylidene fluoride adhesive solution; slowly adding a polyacrylic acid adhesive with ion-transfer function to the above adhesive solution; and mixing the two adhesives by heating to produce a physical crosslinking effect, thereby obtaining a stable and uniform physically crosslinked electrically controlled ionomer adhesive.

[0009] In the above preparation method, the mass fraction of polyvinylidene fluoride in the polyvinylidene fluoride adhesive solution is 0.75%~2%.

[0010] In the above preparation method, the mass ratio of the two binders, polyvinylidene fluoride and polyacrylic acid, is 9:1, 8:2, 7:3 or 6:4.

[0011] In the above preparation method, the temperature for heating and blending the two adhesives is 50~70 ℃.

[0012] The present invention provides a high ionic conductivity composite film electrode prepared from the above-mentioned physically cross-linked electro-controlled ionomer.

[0013] The preparation method of the high ion conductivity composite membrane electrode includes the following steps: weighing electroactive material λ-MnO2 and conductive additives and adding them to the above-prepared physically cross-linked electro-controlled ion gel, and stirring them thoroughly on a magnetic stirrer to prepare an electrode slurry; coating the prepared electrode slurry onto a conductive current collector using a film scraper; and then placing the conductive current collector coated with the electrode slurry in a forced-air drying oven to dry it thoroughly, finally obtaining the high ion conductivity composite membrane electrode.

[0014] In the above-mentioned method for preparing composite film electrodes, the conductive additive is at least one of carbon nanotubes, conductive carbon, and carbon fibers.

[0015] In the above-mentioned method for preparing composite membrane electrodes, the mass ratio of electroactive material λ-MnO2, conductive additive, and binder in the electrode slurry is 6:1:3, 7:1:2, or 8:1:1, and the mass fraction of the binder in the electrocontrolled ion gel is 0.75% to 3.5%.

[0016] In the above-mentioned method for preparing the composite film electrode, the rotation speed of the magnetic stirrer is 400~800 r / min, the stirring time is 6~12 h, and the drying temperature of the composite film electrode is 60~80 ℃.

[0017] In the above-mentioned method for preparing composite film electrodes, the conductive current collector is selected from one of titanium plates, stainless steel sheets, and graphite plates.

[0018] This invention provides the application of the above-mentioned high ion conductivity composite film electrode in the adsorption of lithium ions.

[0019] The beneficial effects of this invention are:

[0020] (1) Electro-controlled ion exchange adhesive uses electrochemically stable polyvinylidene fluoride as a support carrier and polyacrylic acid with ion transfer function as a functional filler. Therefore, it has both excellent electrochemical stability and ion transfer properties and can be used as a special conductive ion exchange adhesive for electro-controlled ion exchange technology.

[0021] (2) Compared with a single polyvinylidene fluoride adhesive, the electro-controlled ion adhesive introduces a polyacrylic acid adhesive containing abundant carboxylic acid groups; the carboxylic acid groups in polyacrylic acid can form hydrogen bond interactions with the hydroxyl groups on the surface of conductive additives and electroactive materials, thereby enabling the electro-controlled ion adhesive to generate stronger adhesion between the conductive additives and electroactive materials.

[0022] (3) The hydrogen protons on the carboxylic acid functional group of the electro-controlled ion gel can undergo ion exchange reaction with lithium ions in the solution, promoting the transfer of lithium ions at the interface of the composite membrane electrode, thereby improving the adsorption performance of the composite membrane electrode for lithium ions.

[0023] (4) Compared with the traditional electrode slurry preparation process, the present invention first synthesizes a liquid physical cross-linked electro-controlled ion gel, and then adds electroactive materials and conductive additives to the electro-controlled ion gel and prepares the electrode slurry by thorough stirring; this process can fully disperse the electroactive materials and conductive additives in the electro-controlled ion gel, thereby further improving the bonding strength of the prepared composite membrane electrode. Attached Figure Description

[0024] Figure 1 This is a diagram of an electrically controlled lithium extraction system consisting of a λ-MnO2-based composite film electrode made of an electrically controlled ionomer and a conductive carbon-based coated electrode, which adsorbs / desorbs lithium ions.

[0025] Figure 2 Impedance test results of λ-MnO2-based composite membrane electrode prepared by electro-controlled ionomer glue and polyvinylidene fluoride binder (inset shows a magnified portion of the impedance test results).

[0026] Figure 3 The lithium-ion adsorption performance of the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 1 of this invention.

[0027] Figure 4 The lithium-ion desorption rate is the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 1 of this invention.

[0028] Figure 5 The lithium-ion adsorption performance of the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 2 of the present invention is shown.

[0029] Figure 6 The lithium-ion desorption rate is the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 2 of this invention.

[0030] Figure 7 The lithium-ion adsorption performance of the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 3 of the present invention is shown.

[0031] Figure 8 The lithium-ion desorption rate is the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 3 of this invention.

[0032] Figure 9 The lithium-ion adsorption performance of the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 4 of this invention.

[0033] Figure 10 The lithium-ion desorption rate is the λ-MnO2-based composite membrane electrode prepared by the electro-controlled ion-gel in Example 4 of this invention.

[0034] In the figure: 1 is the power source, 2 is the raw material solution, 3 is the recovery solution (NaCl solution), A is the conductive carbon-based coated electrode, and B is the λ-MnO2-based composite membrane electrode prepared by electro-controlled ionomer gel. Detailed Implementation

[0035] To make the technical solutions and advantages of the present invention clearer, the present invention will be further illustrated by the following embodiments, but these are not all the embodiments. Example 1

[0036] (1) Weigh 0.27 g of polyvinylidene fluoride adhesive and add it to 31.25 mL of N-methylpyrrolidone solution (so that the mass fraction of polyvinylidene fluoride in the adhesive solution is about 0.8%), and stir thoroughly to dissolve it;

[0037] (2) Slowly add 0.03 g of polyacrylic acid binder to the above solution (so that the mass ratio of polyvinylidene fluoride to polyacrylic acid is 9:1);

[0038] (3) The two adhesives are heated and mixed at 50 °C to form a stable and uniform physically cross-linked electro-ionic adhesive, wherein the mass fraction of the adhesive in the electro-ionic adhesive is 1.0%;

[0039] (4) Add 0.6 g λ-MnO2 and 0.1 g carbon nanotubes to 30 g of the above-synthesized electro-ionic gel and stir it thoroughly on a magnetic stirrer at 400 r / min for 6 hours to prepare electrode slurry;

[0040] (5) The prepared electrode paste was coated onto the titanium plate current collector using a scraper (200 μm) (coating size: 2 cm × 5 cm);

[0041] (6) The titanium plate coated with electrode paste was placed in a forced-air drying oven and dried at 60 °C to obtain a λ-MnO2-based composite membrane electrode with high ionic conductivity. The composite membrane electrode was then assembled into an electrolytic cell for lithium ion adsorption experiments.

[0042] like Figure 1As shown, this invention constructs an electrochemically controlled lithium extraction system by placing a λ-MnO2-based composite membrane electrode B (prepared from an electrochemically controlled ionomer) and a conductive carbon-based coated electrode A at opposite ends of an electrolytic cell. In the electrochemical lithium-ion adsorption stage, a simulated brine feed solution 2 is injected into the electrolytic cell, with the conductive carbon-based coated electrode as the anode and the λ-MnO2-based composite membrane electrode as the cathode. By applying a potential of 1 V to the electrochemically controlled lithium extraction system, lithium ions in the solution are adsorbed onto the composite membrane electrode. Similarly, in the electrochemical lithium-ion desorption stage, a sodium chloride recovery solution 3 is injected into the electrolytic cell, with the λ-MnO2-based composite membrane electrode as the anode and the conductive carbon-based coated electrode as the cathode. By applying a potential of 2 V to the electrochemically controlled lithium extraction system, the lithium ions adsorbed in the composite membrane electrode are desorbed into the sodium chloride recovery solution. Therefore, by alternating the reduction / oxidation states of the composite membrane electrode, the adsorption / desorption of lithium ions by the composite membrane electrode can be achieved.

[0043] The specific operation of the lithium-ion adsorption / desorption process of the composite membrane electrode is as follows: A conductive carbon-based coated electrode and a λ-MnO2-based composite membrane electrode are placed at opposite ends of an electrolytic cell, and 25 mL of simulated brine feed solution with an initial lithium-ion concentration of 200 ppm is weighed and added to the electrolytic cell. Using the conductive carbon-based coated electrode as the anode and the λ-MnO2-based composite membrane electrode as the cathode, an electrochemical adsorption experiment of lithium ions is conducted by applying a potential of 1 V to both electrodes. Figure 3 As shown, after 2 hours of adsorption, the composite membrane electrode adsorbed 8.824 mg / g of lithium ions. After adsorption was complete, the feed solution in the electrolytic cell was drained, and then 25 ml of a 10 g / L sodium chloride recovery solution was added to the electrolytic cell. The λ-MnO2-based composite membrane electrode with adsorbed lithium ions was placed at both ends of the electrolytic cell, with a conductive carbon-based coated electrode as the cathode. An electrochemical desorption experiment of lithium ions was conducted by applying a potential of 2 V to both electrodes. Figure 4 As shown, after 3 hours of desorption, the lithium-ion desorption rate of the composite membrane electrode reached 74.67%.

[0044] Figure 2 Impedance test results for a λ-MnO2-based composite membrane electrode prepared by electro-ionic adhesive and polyvinylidene fluoride binder (inset shows a magnified portion of the impedance test results). Figure 2 It can be seen that, compared with composite film electrodes prepared by a single polyvinylidene fluoride binder, the λ-MnO2-based composite film electrode prepared by electro-controlled ionomer cement exhibits a smaller Nyquist impedance spectrum semicircle diameter in the high-frequency region, indicating that this electrode has a smaller charge transfer resistance. Therefore, Li +It is easier for lithium ions to enter the λ-MnO2-based composite film electrode prepared by electro-controlled ionomer cement. Furthermore, in the low-frequency region, the λ-MnO2-based composite film electrode prepared by electro-controlled ionomer cement exhibits a steeper slope, indicating lower diffusion resistance and better facilitating lithium ion migration within the electrode coating. In summary, the λ-MnO2-based composite film electrode prepared by electro-controlled ionomer cement demonstrates higher ionic conductivity compared to a single polyvinylidene fluoride binder. Example 2

[0045] (1) Weigh 0.16 g of polyvinylidene fluoride adhesive and add it to 12.64 mL of N-methylpyrrolidone solution (so that the mass fraction of polyvinylidene fluoride in the adhesive solution is about 1.2%), and stir thoroughly to dissolve it;

[0046] (2) Slowly add 0.04 g of polyacrylic acid binder to the above solution (so that the mass ratio of polyvinylidene fluoride to polyacrylic acid is 8:2);

[0047] (3) The two adhesives are heated and mixed at 55 °C to form a stable and uniform physically cross-linked electro-ionic adhesive, wherein the mass fraction of the adhesive in the electro-ionic adhesive is 1.5%;

[0048] (4) Add 0.7 g λ-MnO2 and 0.1 g conductive carbon to the 13.01 g of the above-synthesized electro-ion gel and stir it thoroughly on a magnetic stirrer at 500 r / min for 8 hours to prepare electrode slurry;

[0049] (5) The prepared electrode paste is coated onto the stainless steel current collector using a scraper (200 μm) (coating size: 2 cm × 5 cm);

[0050] (6) The titanium plate coated with electrode paste was placed in a forced-air drying oven and dried at 70 °C to obtain a λ-MnO2-based composite membrane electrode with high ionic conductivity. The composite membrane electrode was then assembled into an electrolytic cell for lithium ion adsorption experiments.

[0051] use Figure 1 The apparatus shown is used to conduct adsorption / desorption tests of lithium ions on a composite membrane electrode.

[0052] The specific operation of the lithium-ion adsorption / desorption process of the composite membrane electrode is as follows: A conductive carbon-based coated electrode and a λ-MnO2-based composite membrane electrode are placed at opposite ends of an electrolytic cell, and 25 mL of simulated brine feed solution with an initial lithium-ion concentration of 200 ppm is weighed and added to the electrolytic cell. Using the conductive carbon-based coated electrode as the anode and the λ-MnO2-based composite membrane electrode as the cathode, an electrochemical adsorption experiment of lithium ions is conducted by applying a potential of 1 V to both electrodes. Figure 5As shown, after 2 hours of adsorption, the composite membrane electrode adsorbed 10.766 mg / g of lithium ions. After adsorption was complete, the feed solution in the electrolytic cell was drained, and then 25 ml of a 10 g / L sodium chloride recovery solution was added to the electrolytic cell. The λ-MnO2-based composite membrane electrode with adsorbed lithium ions was placed at both ends of the electrolytic cell, with a conductive carbon-based coated electrode as the cathode. An electrochemical desorption experiment of lithium ions was conducted by applying a potential of 2 V to both electrodes. Figure 6 As shown, after 3 hours of desorption, the lithium-ion desorption rate of the composite membrane electrode reached 79.62%. Example 3

[0053] (1) Weigh 0.07 g of polyvinylidene fluoride adhesive and add it to 4.52 mL of N-methylpyrrolidone solution (so that the mass fraction of polyvinylidene fluoride in the adhesive solution is about 1.5%), and stir thoroughly to dissolve it;

[0054] (2) Slowly add 0.03 g of polyacrylic acid binder to the above solution (so that the mass ratio of polyvinylidene fluoride to polyacrylic acid is 7:3);

[0055] (3) The two adhesives are heated and mixed at 60 °C to form a stable and uniform physically cross-linked electro-ionic adhesive, wherein the mass fraction of the adhesive in the electro-ionic adhesive is 2.1%;

[0056] (4) Add 0.8 g λ-MnO2 and 0.1 g carbon fiber to the 4.68 g of electro-controlled ion gel synthesized above, and stir it thoroughly on a magnetic stirrer at 600 r / min for 10 hours to prepare electrode slurry;

[0057] (5) The prepared electrode paste is coated onto the graphite plate current collector using a scraper (200 μm) (coating size: 2cm × 5cm);

[0058] (6) The graphite plate coated with electrode paste was placed in a forced-air drying oven and dried at 80 °C to obtain a composite membrane electrode with high ionic conductivity. The composite membrane electrode was then assembled into an electrolytic cell for lithium ion adsorption experiments.

[0059] use Figure 1 The apparatus shown is used to conduct adsorption / desorption tests of lithium ions on a composite membrane electrode.

[0060] The specific operation of the lithium-ion adsorption / desorption process of the composite membrane electrode is as follows: A conductive carbon-based coated electrode and a λ-MnO2-based composite membrane electrode are placed at opposite ends of an electrolytic cell, and 25 mL of simulated brine feed solution with an initial lithium-ion concentration of 200 ppm is weighed and added to the electrolytic cell. Using the conductive carbon-based coated electrode as the anode and the λ-MnO2-based composite membrane electrode as the cathode, an electrochemical adsorption experiment of lithium ions is conducted by applying a potential of 1 V to both electrodes. Figure 7 As shown, after 2 hours of adsorption, the composite membrane electrode adsorbed 12.365 mg / g of lithium ions. After adsorption was complete, the feed solution in the electrolytic cell was drained, and then 25 ml of a 10 g / L sodium chloride recovery solution was added to the electrolytic cell. The λ-MnO2-based composite membrane electrode with adsorbed lithium ions was placed at both ends of the electrolytic cell as the anode, and the conductive carbon-based coated electrode was placed as the cathode. An electrochemical desorption experiment of lithium ions was conducted by applying a potential of 2 V to both electrodes. Figure 8 As shown, after 3 hours of desorption, the lithium-ion desorption rate of the composite membrane electrode reached 86.71%. Example 4

[0061] (1) Weigh 0.06 g of polyvinylidene fluoride adhesive and add it to 2.91 mL of N-methylpyrrolidone solution (so that the mass fraction of polyvinylidene fluoride in the adhesive solution is about 2%), and stir thoroughly to dissolve it.

[0062] (2) Slowly add 0.04 g of polyacrylic acid binder to the above solution (so that the mass ratio of polyvinylidene fluoride to polyacrylic acid is 8:2);

[0063] (3) The two adhesives are heated and mixed at 70 °C to form a stable and uniform physically cross-linked electro-ionic adhesive, wherein the mass fraction of the adhesive in the electro-ionic adhesive is 3.3%;

[0064] (4) Add 0.8 g λ-MnO2 and 0.1 g conductive carbon to the 3.05 g of the above-synthesized electro-ion gel and stir it thoroughly on a magnetic stirrer at 800 r / min for 12 hours to prepare electrode slurry;

[0065] (5) The prepared electrode paste is coated onto the graphite plate current collector using a scraper (200 μm) (coating size: 2cm × 5cm);

[0066] (6) The graphite plate coated with electrode paste was placed in a forced-air drying oven and dried at 80 °C to obtain a λ-MnO2-based composite membrane electrode with high ionic conductivity. The composite membrane electrode was then assembled into an electrolytic cell for lithium ion adsorption experiments.

[0067] use Figure 1 The apparatus shown is used to conduct adsorption / desorption tests of lithium ions on a composite membrane electrode.

[0068] The specific operation of the lithium-ion adsorption / desorption process of the composite membrane electrode is as follows: A conductive carbon-based coated electrode and a λ-MnO2-based composite membrane electrode are placed at opposite ends of an electrolytic cell, and 25 mL of simulated brine feed solution with an initial lithium-ion concentration of 200 ppm is weighed and added to the electrolytic cell. Using the conductive carbon-based coated electrode as the anode and the λ-MnO2-based composite membrane electrode as the cathode, an electrochemical adsorption experiment of lithium ions is conducted by applying a potential of 1 V to both electrodes. Figure 9 As shown, after 2 hours of adsorption, the composite membrane electrode adsorbed 14.112 mg / g of lithium ions. After adsorption was complete, the feed solution in the electrolytic cell was drained, and then 25 ml of a 10 g / L sodium chloride recovery solution was added to the electrolytic cell. The λ-MnO2-based composite membrane electrode with adsorbed lithium ions was placed at both ends of the electrolytic cell, with a conductive carbon-based coated electrode as the cathode. An electrochemical desorption experiment of lithium ions was conducted by applying a potential of 2 V to both electrodes. Figure 10 As shown, after 3 hours of desorption, the lithium-ion desorption rate of the composite membrane electrode reached 90.31%.

[0069] The above description is merely an example to clearly illustrate the present invention and is not intended to limit the implementation. Those skilled in the art will be able to make variations or substitutions based on the above examples. All such variations or substitutions should be covered within the scope of protection of this invention.

Claims

1. A method for preparing a composite film electrode with high ionic conductivity, characterized in that... Includes the following steps: Polyvinylidene fluoride (PVDF) adhesive is added to an N-methylpyrrolidone (NMP) solution and stirred thoroughly to dissolve it, thus obtaining a PVDF adhesive solution. An ion-transferring polyacrylic acid (PAA) adhesive is then slowly added to the adhesive solution. The two adhesives are then heated and blended to achieve physical cross-linking, resulting in a stable and uniform physically cross-linked electro-ionic adhesive. Electroactive material λ-MnO2 and conductive additives were weighed and added to the prepared physically cross-linked electro-controlled ionomer, and stirred thoroughly on a magnetic stirrer to prepare an electrode slurry. The prepared electrode slurry was coated onto a conductive current collector using a film scraper. The conductive current collector coated with the electrode slurry was then placed in a forced-air drying oven to dry thoroughly, finally obtaining a high ion conductivity composite membrane electrode. The composite membrane electrode is used to adsorb lithium ions.

2. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The polyvinylidene fluoride adhesive solution contains 0.75% to 2% polyvinylidene fluoride by mass.

3. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The mass ratio of the two adhesives, polyvinylidene fluoride and polyacrylic acid, is 9:1, 8:2, 7:3 or 6:

4.

4. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The temperature for heating and blending the two adhesives is 50~70℃.

5. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The conductive additive is at least one of carbon nanotubes, conductive carbon, and carbon fiber; the conductive current collector is selected from one of titanium plates, stainless steel sheets, and graphite plates.

6. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The mass ratio of electroactive material λ-MnO2, conductive additive, and binder in the electrode slurry is 6:1:3, 7:1:2, or 8:1:1, and the mass fraction of the binder in the electrocontrolled ion adhesive is 0.75% to 3.5%.

7. The method for preparing the high ion conductivity composite film electrode according to claim 1, characterized in that: The magnetic stirrer has a rotation speed of 400~800 r / min and a stirring time of 6~12 h. The composite film electrode has a drying temperature of 60~80 ℃.

8. A high ion conductivity composite film electrode prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the high ionic conductivity composite membrane electrode of claim 8 in the adsorption of lithium ions.

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