Highly rectifying ion diode based on asymmetric aperture gel and method of making same

Abstract

The present application relates to high rectification ion diode based on asymmetric pore size gel and its preparation method. The ion diode device prepared by the preparation method is composed of gel heterojunction and electrode, the pore size of the gel heterojunction is distributed according to the structure of 'big-small-small-big', wherein the large pore size of the gel heterojunction adjacent to the electrode interface ensures the rapid transmission of ions between the gel and the electrode, so that the device has a higher forward current; and the small pore size of the gel heterojunction interface increases the ion selectivity and greatly reduces the generation of reverse leakage current. The forward current of the ion diode device is > 20 mA / cm 2 , and the rectification ratio is up to about 1000, which is 1-2 orders of magnitude higher than that of the traditional ion diode based on symmetric pore size gel.

Description

Technical Field

[0001] This invention relates to the field of ion diode technology, and in particular to a high-rectifier ion diode based on asymmetric aperture gel and its fabrication method. Background Technology

[0002] In recent years, with the rapid development of information technologies such as artificial intelligence and human-computer interaction, novel information devices based on ion carriers have gradually emerged. Compared with traditional electronic devices, ion devices typically possess superior mechanical flexibility and biocompatibility, demonstrating significant advantages in wearable and implantable information monitoring and transmission applications. Furthermore, the diversity of ion species endows ion information with a higher order of degeneracy, meaning that ion devices have more complex and powerful information processing capabilities, providing new ideas for future neural simulation information processing. As the foundation of ion information processing, the development and research of ion diodes with ion rectification effects are of great significance to the development of the field of ion information.

[0003] However, the assembly and packaging of devices are highly challenging due to the tendency of liquid electrolytes to leak. In recent years, researchers have developed flexible and stretchable gel-based ion diodes by constructing polyelectrolyte gel heterojunctions with opposite charges. The polyelectrolyte gel contains ionic groups fixed on a polymer network and mobile counterions. Entropy diffusion of counterions in the heterojunction leads to the formation of an interfacial depletion layer. Under reverse bias, no ion flow occurs at the interface due to the migration of counterions to the same domain, resulting in a heterojunction open circuit; under forward bias, ion flow occurs at the interface due to the migration of counterions to opposite domains, resulting in a heterojunction closed circuit. Compared to solution-based ion diodes, gel-based ion diodes have advantages such as simple structure, no electrolyte leakage, and superior mechanical properties, making them the most widely used ion diodes currently. However, both solution-based and gel-based ion diodes have an ion rectification ratio that is 2-3 orders of magnitude lower than that of traditional semiconductor diodes, severely limiting their rectification efficiency and hindering their application in complex computing or information processing.

[0004] Therefore, the development and research of high-rectifier gel-based ion diodes is crucial to promoting the development and application of biomimetic ion information technology. Currently, by using polyelectrolyte gels with asymmetric pore sizes, which differ from symmetric pore sizes, and polymerizing small-pore gel composite materials with stronger ion selectivity at the interface using a small-pore framework, devices can be assembled and designed. This significantly reduces reverse current while allowing for the generation of large forward current, achieving a major breakthrough in ion rectification ratio.

[0005] However, excessively small pore sizes or excessively large thicknesses can reduce the effective conductivity of the polyelectrolyte gel. Furthermore, both excessively large and small interfacial material thicknesses and pore sizes can lead to a decrease in the rectification ratio of asymmetric aperture ion diodes, significantly reducing the device's signal transmission efficiency. Therefore, it is necessary to rationally design the thickness and pore size distribution of the interfacial composite material to improve the rectification ratio and signal transmission efficiency of ion diodes. Summary of the Invention

[0006] Based on the problems existing in the above-mentioned background technology, the present invention significantly improves the rectification performance of the ion diode of the uniform pore size gel heterojunction by adopting a high rectification performance ion diode design with asymmetric pore size gel and rationally designing the interface material thickness and overall pore size distribution.

[0007] A high-rectification ion diode based on asymmetric pore size gel, comprising a gel heterojunction and electrodes, wherein the gel heterojunction is tightly bonded to the electrodes on both sides to form the high-rectification ion diode, the gel heterojunction comprising asymmetric pore size polyanion gel and asymmetric pore size polycation gel, the asymmetric pore size polyanion gel being composed of a composite of a large-pore size polyanion gel and a small-pore size porous film, the asymmetric pore size polycation gel being composed of a composite of a large-pore size polycation gel and a small-pore size porous film, the gel heterojunction being formed by tightly bonding the asymmetric pore size polyanion gel and the asymmetric pore size polycation gel, and the pore size of the gel heterojunction being distributed in a "large-small-small-large" pattern between the two electrodes.

[0008] Preferably, the electrode is a high specific surface area electrode, and the material used for the high specific surface area electrode includes, but is not limited to, one of the following: metallic materials, carbon materials, transition metal carbides / nitrides, and conductive polymers.

[0009] Preferably, the interior of the macroporous polyanionic gel consists of negatively charged ionic groups fixed on a polymer network and mobile positively charged counterions; the interior of the macroporous polycationic gel consists of positively charged ionic groups fixed on a polymer network and mobile negatively charged counterions. The asymmetric pore size gel polyanionic gel is formed by combining macroporous polyanionic gel with a small-pore film material, creating an integrally embedded structure. The prepolymerization solution of the polyanionic gel completely permeates the small-pore film, participating in the overall polymerization, rather than simply adhering to it; the resulting structure is shown in the attached figure. Figure 1 One side has a large aperture, and the other side has a small aperture.

[0010] Preferably, the method for fabricating a high-rectification ion diode based on asymmetric pore size gel is characterized by comprising the following steps:

[0011] S1: Preparation of asymmetric pore size polyanionic gels by free radical polymerization:

[0012] S1.1: Preparation of polyanionic gel prepolymer solution: First, add anionic monomers to different volumes of solvent to obtain anionic monomers of 0.5-3 mol / L, then add 0.5-100 mmol / L of initiator, and finally add 1-100 mmol / L of crosslinking agent to mix and dissolve to obtain polyanionic gel prepolymer solution.

[0013] S1.2: Surface modification treatment of porous membranes: Prepare an aqueous solution of 1-20 wt% silane coupling agent, immerse a porous membrane with a porosity of 50-90% and a thickness of 10-500 μm in the silane coupling agent solution for 2-48 h, and then place the immersed porous membrane in the air to air dry naturally.

[0014] S1.3: Polymerization of asymmetric pore size polyanionic gel: The porous film obtained in S1.2 is fixed at the bottom of a glass mold with a thickness of 0.1-4 mm. Then, the polyanionic gel prepolymerization solution obtained in S1.1 is poured into the glass mold so that the porous film is fully wetted by the polyanionic gel prepolymerization solution. Finally, the glass mold is placed in an oxygen-free environment for polymerization for 0.5-48 h to obtain asymmetric pore size polyanionic gel.

[0015] S2: Preparation of asymmetric pore size polycationic gels by free radical polymerization:

[0016] S2.1: Preparation of polycationic gel prepolymer solution: First, cationic monomers are added to different volumes of solvent to obtain 0.5-3 mol / L cationic monomers, then 0.5-100 mmol / L initiator is added, and finally 1-100 mmol / L crosslinking agent is added to mix and dissolve to obtain polycationic gel prepolymer solution.

[0017] S2.2: Surface modification treatment of porous membranes: Prepare an aqueous solution of 1-20 wt% silane coupling agent, immerse a porous membrane with a porosity of 50-90% and a thickness of 10-500 μm in the silane coupling agent solution for 2-48 h, and then place the immersed porous membrane in the air to air dry naturally.

[0018] S2.3: Polymerization of asymmetric pore size polycationic gel: The porous film obtained in S2.2 is fixed at the bottom of a glass mold with a thickness of 0.1-4 mm. Then, the polyanionic gel prepolymerization solution obtained in S2.1 is poured into the glass mold, so that the porous film is fully wetted by the polyanionic gel prepolymerization solution. Finally, the glass mold is placed in an oxygen-free environment for polymerization for 0.5-48 h to obtain asymmetric pore size polycationic gel.

[0019] S3: Assembly of gel heterojunction and electrodes:

[0020] S3.1: The asymmetric pore size polyanionic gel obtained in step S1 is tightly bonded with the asymmetric pore size polycationic gel obtained in step S2 to obtain a gel heterostructure with a pore size distribution of "large-small-small-large".

[0021] S3.2: The two sides of the gel heterojunction are tightly bonded to electrodes with high specific surface area to obtain a high-rectification ion diode device.

[0022] Preferably, the solvent in step S1.1 includes, but is not limited to, deionized water, one of organic solvents, or a combination of multiple organic solvents; the solvent in step S2.1 includes, but is not limited to, deionized water, one of organic solvents, or a combination of multiple organic solvents.

[0023] Preferably, the anionic monomer includes, but is not limited to, one of sodium acrylate, sodium styrene sulfonate, potassium acrylamide propyl, sodium 4-vinylpropanesulfonate, and sodium 2-acrylamido-2-methylpropanesulfonate; the cationic monomer includes, but is not limited to, one of 3-acrylamidopropyl-trimethylammonium chloride, acryloyloxyethyl-trimethylammonium chloride, ethylenedimethylammonium chloride, ethyleneimine, and ethyleneamine.

[0024] Preferably, the crosslinking agent includes, but is not limited to, one of N,N'-methylenebisacrylamide, propylenediamine, and acrylic acid.

[0025] Preferably, the initiator includes, but is not limited to, one of redox initiators, organic peroxides, inorganic peroxides, and azo initiators, and the initiation conditions of the initiator include, but are not limited to, heating and light irradiation.

[0026] Preferably, the silane coupling agent includes, but is not limited to, one of 3-(trimethoxysilyl)methacrylate, (3-acryloyloxypropyl)trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0027] Preferably, the porous film includes, but is not limited to, one of cellulose membrane, polypropylene membrane, polyvinylidene fluoride membrane, polytetrafluoroethylene membrane, and anodic aluminum oxide membrane.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] (1) Small-pore composite material: The two sides of the gel heterojunction interface are composite small-pore gel materials formed by polymerization on a small-pore skeleton film with the aid of silane coupling agent solution.

[0030] (2) Asymmetric structure: The pore size of the gel heterojunction is distributed in a “large-small-small-large” structure. The large pore size at the electrode interface ensures the rapid transport of ions between the gel and the electrode, resulting in a high forward current for the device. The small pore size at the gel heterojunction interface increases ion selectivity and significantly reduces the generation of reverse leakage current.

[0031] (3) Performance improvement: The forward current of this ion diode device is >20mA / cm2, and the rectification ratio can reach up to about 1000, which is 1 to 2 orders of magnitude higher than that of traditional ion diodes based on symmetrical aperture gel. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an asymmetric aperture gel ion diode structure.

[0033] Figure 2 SEM images of macroporous gel materials and composite microporous gel materials.

[0034] Figure 3 The current-voltage curves of gel ion diodes with uniform and asymmetric apertures are shown in the voltage range of -5.5V to 5.5V.

[0035] Figure 4 The rectification ratio of the forward current at 5.5V and the reverse current at -5.5V for gel ion diodes with uniform aperture and asymmetric aperture. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] The steps for preparing high-rectifier ion diodes from asymmetric pore size gels via free radical polymerization under light irradiation are as follows:

[0039] In this embodiment, 2 wt% agarose can be added in steps S1.3 and S2.3 to achieve the pre-formation of a physically cross-linked gel, which enhances mechanical strength and facilitates subsequent performance testing. The specific experimental steps are as follows:

[0040] S1: Preparation of asymmetric pore size polyanionic gels by free radical polymerization under light irradiation:

[0041] S1.1: Preparation of the polyanionic gel prepolymer solution: First, prepare a 2.5 mol / L sodium 2-acrylamido-2-methylpropanesulfonate solution (anionic monomer), with ethylene glycol as the solvent; then, add a certain proportion of propylenediamine as a crosslinking agent to 1 mol of anionic monomer solution; finally, add a certain proportion of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone as a UV photoinitiator. The molar ratio of anionic monomer to crosslinking agent is 1:0.001, and the molar ratio of anionic monomer to photoinitiator is 1:0.0005. Finally, stir thoroughly to obtain a uniformly dispersed polyanionic gel prepolymer solution.

[0042] S1.2: Surface modification treatment of porous films: Prepare a 2wt% 3-(trimethoxysilyl)methacrylate solution; immerse a polypropylene (PP) film with a porosity of 55% and a thickness of 25μm in the 3-(trimethoxysilyl)methacrylate solution for 4h for surface modification treatment, and then place the PP film immersed in the 3-(trimethoxysilyl)methacrylate solution in the air to air dry naturally;

[0043] S1.3: Agarose powder enhances mechanical strength: First, take 2g of agarose powder and add it to 10g of polyanionic gel prepolymer solution to obtain a 2wt% mixed solution; then heat and stir on a magnetic stirrer at 95℃ for 20min; then let it stand and heat for 5min until a clear, transparent, bubble-free hot solution is obtained.

[0044] S1.4: Polymerization of asymmetric pore size polyanionic gel: The polypropylene (PP) film obtained in S1.2 was fixed at the bottom of a 1 mm thick glass mold; then, the clear, transparent, bubble-free hot solution obtained in S1.3 was poured into the glass mold, allowing the polypropylene film to be fully wetted; finally, the glass mold was placed under ultraviolet light at a wavelength of 365 nm (4 mW / cm²). 2 Asymmetric pore size polyanionic gel was obtained by simultaneous irradiation of both sides for 2 hours.

[0045] S2: Preparation of asymmetric pore size polycationic gel by free radical polymerization under light irradiation:

[0046] S2.1: Preparation of the polycationic gel prepolymer solution: First, prepare a 2.5 mol / L solution of acryloyloxyethyl-trimethylammonium chloride (cationic monomer) using ethylene glycol as the solvent; then, add a certain proportion of propylenediamine as a crosslinking agent to a 1 mol cationic monomer solution; finally, add a certain proportion of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone as a UV photoinitiator. The molar ratio of cationic monomer to crosslinking agent is 1:0.001, and the molar ratio of cationic monomer to photoinitiator is 1:0.0005. Finally, stir thoroughly to obtain a uniformly dispersed polyanionic gel prepolymer solution.

[0047] S2.2: Surface modification treatment of porous films: Prepare a 2wt% 3-(trimethoxysilyl)propyl methacrylate solution; immerse a polypropylene (PP) film with a porosity of 55% and a thickness of 25μm in the 3-(trimethoxysilyl)propyl methacrylate solution for 4h for surface modification treatment, and then place the PP film immersed in the 3-(trimethoxysilyl)propyl methacrylate solution in the air to air dry naturally;

[0048] S2.3: Agarose powder enhances mechanical strength: First, take 2g of agarose powder and add it to 10g of polycationic gel prepolymer solution to obtain a 2wt% mixed solution; then heat and stir on a magnetic stirrer at 95℃ for 20min; then let it stand and heat for 5min until a clear and transparent bubble-free hot solution is obtained.

[0049] S2.4: Polymerization of asymmetric pore size polycationic gel: The polypropylene (PP) film obtained in S2.2 was fixed at the bottom of a 1 mm thick glass mold; then, the clear, transparent, bubble-free hot solution obtained in S2.3 was poured into the glass mold, allowing the polypropylene film to be fully wetted; finally, the glass mold was placed under ultraviolet light at a wavelength of 365 nm (4 mW / cm²). 2 Asymmetric pore size polycationic gel was obtained by simultaneous irradiation of both sides for 2 hours.

[0050] S3: Assembly of gel heterojunction and electrodes:

[0051] S3.1: The small-pore side of the asymmetric pore size polyanionic gel obtained in step S1 is closely bonded to the small-pore side of the asymmetric pore size polycationic gel obtained in step S2 to obtain a gel heterostructure with a pore size distribution of "large-small-small-large".

[0052] S3.2: After sonicating silver nanowires with a diameter of 150nm and a length of 50μm for 2 hours using an ultrasonic cell disruptor (engineering setting 300W), they were uniformly coated onto a PET film as a high specific area electrode.

[0053] S3.3: The gel heterojunction is tightly bonded to electrodes with high specific surface area on both sides to obtain a high rectification ion diode device. The test results show that the rectification ratio (i.e., the ratio of the current at +5.5V to the current at -5.5V) at ±5.5V is increased from 60.9 to 1165.5.

[0054] Example 2

[0055] The steps for preparing high-rectifier ion diodes using free radical polymerization of asymmetric pore size gels under heating conditions are as follows:

[0056] S1: Preparation of asymmetric pore size polyanionic gels by free radical polymerization under heating conditions:

[0057] S1.1: Preparation of the polyanionic gel prepolymer solution: First, prepare a 3 mol / L solution of sodium 4-vinylpropanesulfonate (anionic monomer) using deionized water as the solvent; then, add a certain proportion of N,N'-methylenebisacrylamide as a crosslinking agent to a 1 mol anionic monomer solution; next, add a certain proportion of ammonium persulfate as a thermal initiator; and finally, add a certain proportion of tetramethylethylenediamine (TMED) as an accelerator. The molar ratio of anionic monomer to crosslinking agent is 1:0.001, the molar ratio of anionic monomer to thermal initiator is 1:0.001, and the molar ratio of anionic monomer to accelerator is 1:0.005. Finally, stir thoroughly to obtain a uniformly dispersed polyanionic gel prepolymer solution.

[0058] S1.2: Surface modification treatment of porous membranes: Prepare a 2wt% (3-acryloyloxypropyl)trimethoxysilane solution; immerse a cellulose membrane with a porosity of 75% and a thickness of 35μm in the (3-acryloyloxypropyl)trimethoxysilane solution for 2h for surface modification treatment, and then place the cellulose membrane immersed in the (3-acryloyloxypropyl)trimethoxysilane solution in the air to air dry naturally;

[0059] S1.3: Polymerization of asymmetric pore size polyanionic gel: The cellulose film obtained in S1.2 is fixed at the bottom of a 0.5 mm thick glass mold; then the polyanionic gel prepolymerization solution in S1.1 is poured into the glass mold, so that the cellulose film is fully wetted by the polyanionic gel prepolymerization solution; finally, the glass mold is placed in a vacuum oven at 60°C and heated for 30 minutes to carry out thermally initiated free radical polymerization to obtain asymmetric pore size polycationic gel;

[0060] S2: Preparation of asymmetric pore size polycationic gel by free radical polymerization under heating conditions:

[0061] S2.1: First, prepare a 2.63 mol / L solution of 3-acrylamidopropyl-trimethylammonium chloride (cationic monomer) using deionized water as the solvent. Then, add a certain proportion of N,N'-methylenebisacrylamide as a crosslinking agent to a 1 mol cationic monomer solution. Next, add a certain proportion of ammonium persulfate as a thermal initiator, and finally add a certain proportion of tetramethylethylenediamine (TMED) as an accelerator. The molar ratio of cationic monomer to crosslinking agent is 1:0.001, the molar ratio of cationic monomer to thermal initiator is 1:0.002, and the molar ratio of cationic monomer to accelerator is 1:0.01. Finally, stir thoroughly to obtain a uniformly dispersed polycationic gel prepolymer solution.

[0062] S2.2: Surface modification treatment of porous membranes: Prepare a 2wt% (3-acryloyloxypropyl)trimethoxysilane solution; immerse a cellulose membrane with a porosity of 75% and a thickness of 35μm in the (3-acryloyloxypropyl)trimethoxysilane solution for 2h for surface modification treatment, and then place the cellulose membrane immersed in the (3-acryloyloxypropyl)trimethoxysilane solution in the air to air dry naturally;

[0063] S2.3: Polymerization of asymmetric pore size polycationic gel: The cellulose film obtained in S2.2 is fixed at the bottom of a 0.5 mm thick glass mold; then the polycationic gel prepolymerization solution in S2.1 is poured into the glass mold, so that the cellulose film is fully wetted by the polycationic gel prepolymerization solution; finally, the glass mold is placed in a vacuum oven at 60°C and heated for 30 min to carry out thermally initiated free radical polymerization to obtain asymmetric pore size polycationic gel;

[0064] S3: Assembly of gel heterojunction and electrodes:

[0065] S3.1: The small-pore side of the asymmetric pore size polyanionic gel obtained in step S1 is closely bonded to the small-pore side of the asymmetric pore size polycationic gel obtained in step S2 to obtain a gel heterostructure with a pore size distribution of "large-small-small-large".

[0066] S3.2: After sonicating a 2wt% Ti3C2 solution (transition metal carbon / nitride) for 1 hour using an ultrasonic cell disruptor (engineering setting 300W), it was uniformly coated onto PET (engineering setting 300W) as a high specific area electrode.

[0067] S3.3: The gel heterojunction is tightly bonded to electrodes with high specific surface area on both sides to obtain a high rectification ion diode device. The test results show that the rectification ratio (i.e., the ratio of the current at +5.5V to the current at -5.5V) at ±5.5V increases from 54.8 to 977.8.

[0068] Figure 1A schematic diagram of an asymmetric aperture gel ion diode: The high-rectification ion diode includes a gel heterojunction and electrodes at both ends. The gel heterojunction is formed by tightly bonding asymmetric aperture polyanionic gel and asymmetric aperture polycationic gel according to a "large-small-small-large" pore size distribution.

[0069] Figure 2 SEM images of large-pore gel materials and composite small-pore gel materials: Figure 2 (a) is a SEM image of a large-pore gel with a scale bar of 50 μm. Figure 2 (c) is a SEM image of the macroporous gel with a scale bar of 10 μm. The image shows that the pore diameter of the macroporous gel material is mostly distributed in the range of 5–20 μm. Figure 2 (b) is a SEM image of a small-pore gel with a scale bar of 50 μm. Figure 2 (d) is a SEM image of a small-pore gel with a scale bar of 10 μm. The image shows that the pore diameter of the small-pore gel material is mostly distributed in the range of 0.5 to 3 μm.

[0070] Figure 3 Current-voltage curves for gel ion diodes with uniform and asymmetric pore sizes in the voltage range of -5.5V to 5.5V: The gel used in the test was measured per unit area (1 cm²). 2 Therefore, the vertical axis represents current density, and the horizontal axis represents voltage. The graph shows that the reverse current of a uniform aperture at -5.5V is -0.53 mA / cm². 2 The forward current at 5.5V is 29.14mA / cm. 2 The reverse current of the asymmetric aperture at -5.5V is -0.02mA / cm. 2 The forward current at 5.5V is 20.54mA / cm. 2 With a 29.5% reduction in forward current, the reverse current was reduced by 99.6%.

[0071] Figure 4 The rectification ratios of the forward current at 5.5V and the reverse current at -5.5V are given for gel ion diodes with uniform and asymmetric apertures. For the symmetric aperture, the rectification ratio of the forward current at 5.5V to the reverse current at -5.5V is 54.8; for the asymmetric aperture, the rectification ratio is 977.8, resulting in a 1684.3% improvement in rectification ratio.

[0072] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-rectifier ion diode based on asymmetric pore size gel, characterized in that: The high-rectification ion diode includes a gel heterojunction and electrodes. The gel heterojunction is tightly bonded to the electrodes on both sides to form the high-rectification ion diode. The gel heterojunction includes an asymmetric-pore size polyanion gel and an asymmetric-pore size polycation gel. The asymmetric-pore size polyanion gel is composed of a large-pore size polyanion gel and a small-pore size porous film. The asymmetric-pore size polycation gel is composed of a large-pore size polycation gel and a small-pore size porous film. The gel heterojunction is formed by tightly bonding the asymmetric-pore size polyanion gel and the asymmetric-pore size polycation gel. The pore diameter of the large-pore size gel material is distributed in the range of 5 to 20 μm; the pore diameter of the small-pore size gel material is distributed in the range of 0.5 to 3 μm. The pore size of the gel heterojunction is distributed in a "large-small-small-large" pattern between the two electrodes.

2. The high-rectification ion diode based on asymmetric pore size gel according to claim 1, characterized in that: The electrode is a high specific surface area electrode, and the material used for the high specific surface area electrode includes one of the following: metallic materials, carbon materials, transition metal carbides / nitrides, and conductive polymers.

3. The high-rectification ion diode based on asymmetric pore size gel according to claim 1, characterized in that: The interior of the macroporous polyanionic gel is composed of negatively charged ionic groups fixed on a polymer network and mobile positively charged counterions, while the interior of the macroporous polycationic gel is composed of positively charged ionic groups fixed on a polymer network and mobile negatively charged counterions.

4. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Preparation of asymmetric pore size polyanionic gels by free radical polymerization: S1.1: Preparation of polyanionic gel prepolymer solution: First, add anionic monomers to different volumes of solvent to obtain anionic monomers of 0.5-3 mol / L, then add an initiator of 0.5-100 mmol / L, and finally add a crosslinking agent of 1-100 mmol / L to mix and dissolve to obtain polyanionic gel prepolymer solution. S1.2: Surface modification treatment of porous membranes: Prepare an aqueous solution of 1-20 wt% silane coupling agent, immerse a porous membrane with a porosity of 50-90% and a thickness of 10-500 μm in the silane coupling agent solution for 2-48 h, and then place the immersed porous membrane in the air to air dry naturally. S1.3: Polymerization of asymmetric pore size polyanionic gel: The porous film obtained in S1.2 is fixed at the bottom of a glass mold with a thickness of 0.1-4 mm. Then, the polyanionic gel prepolymerization solution obtained in S1.1 is poured into the glass mold, so that the porous film is fully wetted by the polyanionic gel prepolymerization solution. Finally, the glass mold is placed in an oxygen-free environment for polymerization for 0.5-48 h to obtain asymmetric pore size polyanionic gel. S2: Preparation of asymmetric pore size polycationic gels by free radical polymerization: S2.1: Preparation of polycationic gel prepolymer solution: First, cationic monomers are added to different volumes of solvent to obtain 0.5-3 mol / L cationic monomers, then 0.5-100 mmol / L initiator is added, and finally 1-100 mmol / L crosslinking agent is added to mix and dissolve to obtain polycationic gel prepolymer solution; S2.2: Surface modification treatment of porous membranes: Prepare an aqueous solution of 1-20 wt% silane coupling agent, immerse a porous membrane with a porosity of 50-90% and a thickness of 10-500 μm in the silane coupling agent solution for 2-48 h, and then place the immersed porous membrane in the air to air dry naturally. S2.3: Polymerization of asymmetric pore size polycationic gel: The porous film obtained in S2.2 is fixed at the bottom of a glass mold with a thickness of 0.1-4 mm. Then, the polyanionic gel prepolymerization solution obtained in S2.1 is poured into the glass mold, so that the porous film is fully wetted by the polyanionic gel prepolymerization solution. Finally, the glass mold is placed in an oxygen-free environment for polymerization for 0.5-48 h to obtain asymmetric pore size polycationic gel. S3: Assembly of gel heterojunction and electrodes: S3.1: The asymmetric pore size polyanionic gel obtained in step S1 is tightly bonded with the asymmetric pore size polycationic gel obtained in step S2 to obtain a gel heterostructure with a pore size distribution of "large-small-small-large". S3.2: The two sides of the gel heterojunction are tightly bonded to electrodes with high specific surface area to obtain a high-rectification ion diode device.

5. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The solvent in step S1.1 includes deionized water, one of organic solvents, or a combination of multiple organic solvents; the solvent in step S2.1 includes deionized water, one of organic solvents, or a combination of multiple organic solvents.

6. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The anionic monomer includes one of sodium acrylate, sodium styrene sulfonate, potassium acrylamide propyl, sodium 4-vinylpropanesulfonate, and sodium 2-acrylamido-2-methylpropanesulfonate; the cationic monomer includes one of 3-acrylamidopropyl-trimethylammonium chloride, acryloyloxyethyl-trimethylammonium chloride, ethylenedimethylammonium chloride, ethyleneimine, and ethyleneamine.

7. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The crosslinking agent includes one of N,N'-methylenebisacrylamide, propylenediamine, and acrylic acid.

8. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The initiator includes one of redox initiators, organic peroxides, inorganic peroxides, and azo initiators, and the initiation conditions of the initiator include one of heating and light irradiation.

9. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The silane coupling agent includes one of 3-(trimethoxysilyl)methacrylate, (3-acryloyloxypropyl)trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

10. The method for fabricating a high-rectifier ion diode based on asymmetric pore size gel according to claim 4, characterized in that: The porous membrane includes one of cellulose membrane, polypropylene membrane, polyvinylidene fluoride membrane, polytetrafluoroethylene membrane, and anodic aluminum oxide membrane.

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