Nanometer confinement fluid mediated capacitive ion diode and preparation method thereof

Abstract

The invention discloses a nano confinement fluid mediated capacitive ion diode and a preparation method thereof, and belongs to the technical field of electrochemical energy storage and ion / electron coupling circuits. The ion diode comprises a tungsten oxide-based working electrode, a porous carbon-based counter electrode and an acidic electrolyte, wherein the tungsten oxide-based working electrode takes tungsten oxide dihydrate, tungsten oxide monohydrate or anhydrous tungsten oxide as an active material, an electrode structure with different nanometer confinement spaces is constructed by accurately regulating and controlling the content of crystal water, and the ion screening effect and transmission kinetics are remarkably enhanced. The preparation method comprises the steps of pretreatment of tungsten oxide powder, regulation and control of crystal water, preparation of electrode slurry, coating of a current collector, preparation of an electrolyte and assembly and packaging of a device. The ion diode has the advantages of high rectification ratio, high response frequency and excellent biocompatibility, can be widely applied to brain-computer interfaces, brain-like calculation and ion electronic coupling logic circuits, and solves the problems of low rectification performance, poor biocompatibility and the like of existing devices.

Description

TECHNICAL FIELD

[0001] The application discloses a nano-confined fluid-mediated capacitive ion diode and a preparation method thereof, and belongs to the field of electrochemical energy storage and the field of emerging ion / electron coupled circuits. BACKGROUND

[0002] In biological systems, neural networks with complex morphology and highly polarized interface architecture can support complex communication of biological ions and biochemical signals between different neurons, which is fundamentally different from the current electronic devices that use electrons and holes to realize computing or data storage functions. The difference in information carriers between the two systems brings great challenges to the deep integration and information transmission of the two systems, so it is urgent to develop ion / electron coupled devices with logic operation functions to realize seamless connection and information interaction between the two systems. Capacitive ion diode is a new type of electrochemical functional device based on supercapacitor, which has the same device structure as supercapacitor and similar unidirectional conduction characteristics as semiconductor diode, and is one of the most potential basic components for building new ion / electron coupled circuits. Capacitive ion diode can integrate moving ions and electrons in one circuit, and can convert ion signals and electrical signals between non-biological and biological systems, which is expected to have great potential in the field of brain-computer interface and realize in-depth human-computer interaction.

[0003] Despite the above advantages, the further development and application of capacitive ion diodes in human-computer interaction is largely dependent on the optimization and improvement of key performance indicators such as rectification ratio, response frequency, and cycle stability. Nano confinement effect refers to the changes in the physical and chemical properties of materials due to spatial constraints at the nanoscale. When the size of a material is reduced to the nanoscale, the movement of electrons, holes, or other particles is confined to a very small space, causing their energy states to be quantized, which in turn changes the optical, electrical, and other physical properties of the material. Nano-confined fluids are essentially crystalline water in materials. Since the crystalline water is confined in a nano or sub-nano space, it is called a nano-confined fluid. When the confinement space of the related matrix is reduced to a few nanometers or even smaller, the phase behavior of the confined space and the related chemical reaction path often change significantly, i.e., nano-confinement effect, which in turn affects the net pollution behavior and mechanism of the related composite nanomaterials. Nano-confined space can change the hydrogen bond network of water molecules, and in turn make the confined water phase exhibit abnormal thermodynamic, kinetic, and fluid mechanical properties and behaviors, and affect water treatment effect through changes in the number of water molecule hydrogen bonds and ultrafast fluid mechanics. For example, the nano-confined space formed by crystalline water in dihydrate tungsten oxide (WO3·2H2O), monohydrate tungsten oxide (WO3·H2O), and anhydrous tungsten oxide (WO3) will exhibit different electrochemical properties due to the combined effects of its interlayer spacing, hydrogen bond network, and various effects. According to the Bragg equation, the interlayer spacing of the three materials is 6.93, 5.34, and 3.84 angstroms (Å), respectively. Different interlayer spacings affect the bonding structure of tungsten oxide and interlayer crystalline water and the distribution of interlayer charges, i.e., different nano-confined spaces are formed. In energy storage devices such as batteries and supercapacitors, nano-confinement effect helps to improve ion transport rate and battery performance. Nano-confined electrolytes break through traditional ion conductivity and provide a new way of thinking for high-efficiency energy storage applications. In essence, ion transport in nano-confined space is the most basic process in capacitive ion diodes, and the introduction of nano-confined fluids can precisely regulate the ion rectification performance under the dual influence of charge effect and size effect. Tungsten oxide prepared by conventional process has not been used in ion diodes before, and the effect of crystalline water content on its rectification performance is first discovered. In recent years, many materials have been applied to ion diodes, such as ZnCo2O4, Ni3Bi2S2, TMaterials such as Nb₂O₅, when applied to ion diodes, exhibit rectification ratios of 12, 37, and 10⁸, and response frequencies of 0.1 Hz, 0.05 Hz, and 122 Hz, respectively, but none show good biocompatibility. Therefore, selecting a suitable pseudocapacitive material as the working electrode and precisely controlling the ion transport behavior within the nanoscale confinement space is key to constructing high-performance ion diodes. This approach holds promise for solving the problems of low rectification ratio, limited response frequency, and poor biocompatibility in existing capacitive ion diodes, and has significant scientific and application value. Summary of the Invention

[0004] To address the shortcomings of existing methods and technologies, this invention aims to provide a nano-confined fluid-mediated capacitive ion diode and its fabrication method, thereby enriching the material system of capacitive ion diodes, improving their overall performance, and broadening their application fields. This invention is the first (and the first to explicitly state the use of water of crystallization in the specification) to propose optimizing the ion sieving effect and ion transport kinetics of electrode materials by precisely controlling the interlayer water of crystallization. Using layered tungsten oxide (WO3·nH2O, n=0,1,2) with different water of crystallization contents as a model system, the optimal material is selected as the working electrode. This is combined with biocompatible activated carbon as the electrode and a biocompatible encapsulation material to construct a high-performance biocompatible capacitive ion diode. The ion diode constructed using this method achieves a synergistic improvement in overall performance and is expected to play a significant role in brain-computer interfaces, enabling in-depth human-computer interaction and showing broad application prospects in emerging fields such as brain-like computing and neural network interaction.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a nano-confined fluid-mediated capacitive ion diode, comprising a tungsten oxide-based working electrode, a porous carbon-based counter electrode, and an acidic electrolyte. The tungsten oxide-based working electrode comprises a tungsten oxide slurry and a current collector, the tungsten oxide slurry being coated on the surface of the current collector to form the tungsten oxide-based working electrode. The tungsten oxide slurry comprises an active material I, a conductive agent, and a binder, wherein the active material I is tungsten oxide dihydrate or tungsten oxide monohydrate, and the active material I, the conductive agent, and the binder are mixed and dispersed in a dispersant to form the tungsten oxide slurry. The porous carbon-based counter electrode comprises a porous carbon slurry and a current collector, the porous carbon slurry being coated on the surface of the current collector to form the porous carbon-based counter electrode. The porous carbon slurry comprises an active material II, a conductive agent, and a binder, the active material II, the conductive agent, and the binder being mixed and dispersed in a dispersant to form the porous carbon slurry. The tungsten oxide-based working electrode and the porous carbon-based counter electrode are assembled and then added to an acidic electrolyte to obtain the capacitive ion diode. Further, the mass ratio of active material I or active material II, conductive agent, and binder excluding the dispersant is 5-8:1-4:1. Further, active material II is a porous carbon material, such as activated carbon, biomass carbon, polymer-derived carbon, organic small-molecule derived carbon, graphene, graphyne, or carbon nanotubes. Further, the electrolyte in the acidic electrolyte is one or more inorganic or organic acids, including hydrochloric acid, sulfuric acid, phosphoric acid, and perchloric acid, and organic acids including acetic acid, alginic acid, citric acid, polyacrylic acid, and polystyrene sulfonic acid. Further, the conductive agent is conductive carbon black, Ketjen black, acetylene black, carbon nanotubes, graphene nanosheets, or graphite powder; the binder is polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, sodium carboxymethyl cellulose, polyacrylic acid, polyethylene oxide, styrene-butadiene rubber, or sodium alginate; the dispersant is deionized water, ethanol, ethylene glycol, acetone, acetonitrile, propylene carbonate, N-methylpyrrolidone, N,N-dimethylformamide, or dimethyl sulfoxide; and the current collector is aluminum foil, copper foil, titanium foil, nickel foil, gold foil, platinum foil, stainless steel mesh, nickel foam, copper foam, graphite foil, carbon paper, or carbon cloth.

[0006] The present invention also provides a method for fabricating the above-mentioned nano-confined fluid-mediated capacitive ion diode, comprising: S1-1, Pretreatment of Tungsten Oxide Dihydrate: Place tungsten oxide dihydrate powder in a centrifuge tube, add anhydrous ethanol until the powder is completely submerged, place the centrifuge tube in a centrifuge, and centrifuge at 2500 rpm for 10 min. After centrifugation, remove the centrifuge tube and slowly pour off the supernatant. This step constitutes one cycle. Repeat the above cycle 3 times. After the last centrifugation, collect the tungsten oxide dihydrate at the bottom of the centrifuge tube and dry it at 60℃ for 4 h to obtain tungsten oxide dihydrate powder. Further, it also includes: S1-2, Preparation of Tungsten Oxide Monohydrate: Based on the tungsten oxide dihydrate obtained in S1-1, place the obtained tungsten oxide dihydrate in an environment of 60℃, then raise the temperature to 100℃ at a rate of 10℃ / min, and dry it at 100℃ with forced air for 2 h. After 2 h, continue forced air drying until the temperature inside the chamber drops to room temperature to obtain tungsten oxide monohydrate powder. Further, it includes: S1, preparing a tungsten oxide-based working electrode: based on the tungsten oxide dihydrate powder or tungsten oxide monohydrate powder prepared in S1-1 or S1-2, one of the tungsten oxide dihydrate powder or tungsten oxide monohydrate powder is used as active material I, and is weighed with a conductive agent and a binder in a certain proportion, and then mixed with a dispersant to obtain a tungsten oxide slurry. The tungsten oxide slurry is uniformly coated on a current collector, dried, and cut to obtain a tungsten oxide-based working electrode; S2, preparing a porous carbon-based counter electrode: using porous carbon material as active material II, and a conductive agent and a binder... A porous carbon slurry is obtained by mixing an agent and a dispersant. This porous carbon slurry is then uniformly coated onto a current collector, dried, and cut to obtain a porous carbon-based counter electrode. S3: Preparation of an acidic electrolyte: An inorganic or organic acid is selected as the electrolyte, and a solvent is added to prepare an electrolyte with a concentration of 0.01-10 mol / L. S4: Preparation of a capacitive ion diode: The tungsten oxide-based working electrode and the porous carbon-based counter electrode obtained in step S2 are assembled, and the electrolyte prepared in step S3 is injected into them. After encapsulation, a tungsten oxide-based capacitive ion diode is obtained. Further, the tungsten oxide-based capacitive ion diode described in step S4 can be in the form of a button cell, sandwich cell, pouch cell, or planar interdigitated cell.

[0007] Compared with the prior art, the present invention has at least the following beneficial effects: First, based on an in-depth analysis of the working principle of capacitive ion diodes, this invention innovatively proposes to optimize the ion rectification characteristics of materials by precisely controlling the nano-confined fluid through a specific tungsten oxide preparation method. The optimized material is then combined with a biocompatible activated carbon electrode to construct a high-performance layered tungsten oxide-based ion diode, which effectively solves the problems of low rectification ratio, limited response frequency, and poor biocompatibility of existing ion diodes.

[0008] Secondly, the preparation techniques for the layered tungsten oxide material and carbon material used in the method of the present invention are mature, simple, readily available, and inexpensive, making them suitable for mass production.

[0009] Third, the electrode preparation method used in the present invention has a mature process route, is highly compatible with various types of electrode materials and existing electrode production lines, is suitable for large-scale production, and is inexpensive. Attached Figure Description

[0010] Figure 1 This is a low-magnification scanning electron microscope image of the tungsten oxide dihydrate material from Example 1 of the present invention; Figure 2 This is a low-magnification scanning electron microscope image of a hydrated tungsten oxide material from Example 1 of the present invention; Figure 3 This is a low-magnification scanning electron microscope image of the anhydrous tungsten oxide material in Example 1 of the present invention; Figure 4 This is a high-magnification scanning electron microscope image of the tungsten oxide dihydrate material from Example 1 of the present invention; Figure 5 This is a high-magnification scanning electron microscope image of a hydrated tungsten oxide material from Example 1 of the present invention; Figure 6 This is a high-magnification scanning electron microscope image of the anhydrous tungsten oxide material in Example 1 of the present invention; Figure 7 The X-ray diffraction pattern of the tungsten oxide dihydrate material in Example 1 of this invention is shown below. Figure 8 The X-ray diffraction pattern of the hydrated tungsten oxide material in Example 1 of this invention is shown below. Figure 9 The X-ray diffraction pattern of the anhydrous tungsten oxide material in Example 1 of this invention; Figure 10 This is a comparison chart of the cyclic voltammetry curves of the three electrode materials in Example 1 of the present invention; Figure 11 This is a comparison chart of the constant current charge-discharge curves of the three electrode materials in Embodiment 1 of the present invention; Figure 12 The cyclic voltammetry curve of the dihydrate layered tungsten oxide-based capacitive ion diode of Embodiment 1 of the present invention is shown below. Figure 13 The cyclic voltammetry curve of a hydrated layered tungsten oxide-based capacitive ion diode according to Embodiment 2 of the present invention is shown below. Figure 14 The cyclic voltammetry curve of the anhydrous layered tungsten oxide-based capacitive ion diode of Embodiment 3 of the present invention is shown below. Figure 15 The constant current charge-discharge curve of the dihydrate layered tungsten oxide-based capacitive ion diode of Embodiment 1 of the present invention; Figure 16 The constant current charge-discharge curve of a hydrated layered tungsten oxide-based capacitive ion diode in Embodiment 2 of the present invention; Figure 17 The constant current charge-discharge curve of the dehydrated layered tungsten oxide-based capacitive ion diode in Embodiment 3 of the present invention; Figure 18 The first type of rectification ratio of the dihydrated layered tungsten oxide-based capacitive ion diode of Embodiment 1 of the present invention; Figure 19 The first type of rectification ratio of a hydrated layered tungsten oxide-based capacitive ion diode according to Embodiment 2 of the present invention; Figure 20 The first type of rectification ratio of the anhydrous layered tungsten oxide-based capacitive ion diode in Embodiment 3 of the present invention; Figure 21 This represents the second type of rectification ratio of the dihydrated layered tungsten oxide-based capacitive ion diode of Embodiment 1 of the present invention;Figure 22 This refers to the second type of rectification ratio of a hydrated layered tungsten oxide-based capacitive ion diode according to Embodiment 2 of the present invention. Figure 23 This represents the second type of rectification ratio of the anhydrous layered tungsten oxide-based capacitive ion diode in Embodiment 3 of the present invention. Figure 24 This is an example of the application of a hydrated layered tungsten oxide-based capacitive ion diode in an AND gate, as described in Embodiment 2 of the present invention. Figure 25 This invention provides an example of the application of a hydrated layered tungsten oxide-based capacitive ion diode in an OR gate. Detailed Implementation

[0011] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0012] A nano-confined fluid-mediated capacitive ion diode is disclosed. The capacitive ion diode comprises a tungsten oxide-based working electrode, a porous carbon-based counter electrode, and an acidic electrolyte. The tungsten oxide-based working electrode includes a tungsten oxide slurry and a current collector. The tungsten oxide slurry is coated on the surface of the current collector to form the tungsten oxide-based working electrode. The tungsten oxide slurry includes an active material I, a conductive agent, and a binder. Active material I is either dihydrated or monohydrated tungsten oxide. Active material I, the conductive agent, and the binder are mixed and dispersed in a dispersant to form the tungsten oxide slurry. The porous carbon-based counter electrode includes a porous carbon slurry and a current collector. The porous carbon slurry is coated on the surface of the current collector to form the porous carbon-based counter electrode. The porous carbon slurry includes an active material II, a conductive agent, and a binder. Active material II, the conductive agent, and the binder are mixed and dispersed in a dispersant to form the porous carbon slurry. After assembling the tungsten oxide-based working electrode and the porous carbon-based counter electrode, an acidic electrolyte is added to obtain the capacitive ion diode.

[0013] In the embodiments of the present invention, the tungsten oxide-based working electrode is composed of tungsten oxide slurry and current collector, wherein the active material I in the tungsten oxide slurry is either tungsten oxide dihydrate or tungsten oxide monohydrate. The capacitive ion diode composed of the above materials has a very significant ion sieving effect. These excellent ion rectification properties enable the capacitive ion diode assembled from the tungsten oxide monohydrate electrode to exhibit ideal unidirectional energy storage behavior.

[0014] In this embodiment of the invention, the mass ratio of active material I or active material II, conductive agent, and binder before they are mixed with the dispersant is 5-8:1-4:1, preferably 8:1:1.

[0015] In this embodiment of the invention, the active material II is a porous carbon material. Porous carbon materials in this embodiment include, but are not limited to, activated carbon, biomass carbon, polymer-derived carbon, organic small molecule-derived carbon, graphene, graphyne, or carbon nanotubes. These porous carbon materials are readily available, and the counter electrode prepared using them exhibits stable performance.

[0016] The electrolyte in the acidic electrolyte is one or more inorganic or organic acids. Inorganic acids include, but are not limited to, hydrochloric acid, sulfuric acid, phosphoric acid, and perchloric acid, while organic acids include, but are not limited to, acetic acid, alginic acid, citric acid, polyacrylic acid, and polystyrene sulfonic acid. The selection criterion is that only one of the cations and anions of the inorganic or organic salt can be efficiently stored in the metal oxide material. To ensure the prepared electrolyte has good electrochemical stability and high ionic conductivity, the solvent is not limited to a single solvent; two or more mixed solvents can be selected as needed, and specific functional organic small molecules or inorganic salt additives can also be introduced.

[0017] Conductive agents include, but are not limited to, conductive carbon black, Ketjen black, acetylene black, carbon nanotubes, graphene nanosheets, or graphite powder; binders include, but are not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, sodium carboxymethyl cellulose, polyacrylic acid, polyethylene oxide, styrene-butadiene rubber, or sodium alginate; dispersants include, but are not limited to, deionized water, ethanol, ethylene glycol, acetone, acetonitrile, propylene carbonate, N-methylpyrrolidone, N,N-dimethylformamide, or dimethyl sulfoxide. The conductive agents, binders, and dispersants mentioned above work synergistically with the metal oxide material to ensure that the metal oxide-based working electrode selectively stores anions and cations in the electrolyte, resulting in high unidirectional energy storage density, high rectification ratio, and high stability of the metal oxide-based capacitive ion diode.

[0018] Current collectors include, but are not limited to, aluminum foil, copper foil, titanium foil, nickel foil, gold foil, platinum foil, stainless steel mesh, nickel foam, copper foam, graphite foil, carbon paper, or carbon cloth. Current collectors made of these materials have low internal resistance, allowing them to collect the current generated by metal oxide materials and form a larger output current.

[0019] The present invention also provides a method for fabricating the above-mentioned nano-confined fluid-mediated capacitive ion diode, comprising: S1-1. Pretreatment of tungsten oxide dihydrate: Place tungsten oxide dihydrate powder in a centrifuge tube, add anhydrous ethanol until the powder is completely submerged, place the centrifuge tube in a centrifuge, and centrifuge at 2500 rpm for 10 min. After centrifugation, remove the centrifuge tube and slowly pour out the supernatant. The above steps constitute one cycle. Repeat the above cycle 3 times. After the last centrifugation, collect the tungsten oxide dihydrate at the bottom of the centrifuge tube and dry it at 60℃ for 4 h to obtain tungsten oxide dihydrate powder.

[0020] Furthermore, it also includes: S1-2, Preparation of hydrated tungsten oxide: Based on the tungsten oxide dihydrate prepared by S1-1, the prepared tungsten oxide dihydrate was placed in an environment of 60°C, and then the temperature was increased to 100°C at a rate of 10°C / min. It was then dried by blowing air at 100°C for 2 hours. After 2 hours, the blowing air was continued until the temperature inside the chamber dropped to room temperature, thus obtaining tungsten oxide monohydrate powder.

[0021] In this embodiment of the invention, the ratio of tungsten oxide to bound water is precisely controlled using the above preparation method to obtain monohydrated tungsten oxide, which is structurally layered tungsten oxide. This optimizes the ion sieving effect and ion transport kinetics of the electrode material, giving it the characteristics of high rectification ratio, high stability and excellent biocompatibility.

[0022] Furthermore, including: S1. Preparation of tungsten oxide-based working electrode: Based on the tungsten oxide dihydrate or tungsten oxide monohydrate powder prepared in S1-1 or S1-2, one of the tungsten oxide dihydrate or tungsten oxide monohydrate powders is used as active material I, weighed in proportion with a conductive agent and a binder, and then mixed with a dispersant to obtain a tungsten oxide slurry. The tungsten oxide slurry is uniformly coated on a current collector, dried, and cut to obtain a tungsten oxide-based working electrode. The dispersant will evaporate during the drying process.

[0023] S2. Preparation of porous carbon-based counter electrode: Porous carbon material is used as active material II, along with a conductive agent, binder, and dispersant to obtain a porous carbon slurry. The porous carbon slurry is then uniformly coated onto a current collector, dried, and cut to obtain a porous carbon-based counter electrode. The dispersant evaporates during the drying process.

[0024] To ensure that the final constructed capacitive ion diode can work efficiently, in this embodiment of the invention, the loading of the porous carbon-based electrode active material is 1 to 10 times, preferably 1 to 2 times, the loading of the metal oxide-based working electrode active material.

[0025] S3. Preparation of acidic electrolyte: Inorganic or organic acids are selected as electrolytes, and solvents are added to prepare electrolyte solutions with a concentration of 0.01-10 mol / L.

[0026] S4. Fabrication of capacitive ion diodes: The tungsten oxide-based working electrode and the porous carbon-based counter electrode obtained in step S2 are assembled, and the electrolyte prepared in step S3 is injected into them. After encapsulation, a tungsten oxide-based capacitive ion diode is obtained.

[0027] In this embodiment of the invention, the device form of the tungsten oxide-based capacitive ion diode described in S4 includes, but is not limited to, button type, sandwich type, pouch type, or planar interdigitated type.

[0028] The characterization and testing methods used in all the following embodiments are as follows: 1) Scanning electron microscope: to observe the microstructure of layered tungsten oxide materials.

[0029] 2) X-ray diffractometer: Tests the X-ray diffraction pattern of layered tungsten oxide materials.

[0030] 3) Electrochemical workstation: Test the cyclic voltammetry curves and constant current charge-discharge curves of three layered tungsten oxide materials and tungsten oxide-based capacitive ion diodes.

[0031] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0032] Example 1 A nano-confined fluid-mediated capacitive ion diode comprises a tungsten oxide-based working electrode, a porous carbon-based counter electrode, and an acidic electrolyte. The tungsten oxide-based working electrode includes a tungsten oxide slurry and a current collector. The tungsten oxide slurry is coated on the surface of the current collector, which is a graphite foil, forming the tungsten oxide-based working electrode. The tungsten oxide slurry includes an active material I, a conductive agent, and a binder. The active material I is tungsten oxide dihydrate, the conductive agent is conductive carbon black, and the binder is polyvinylidene fluoride. The active material I, the conductive agent, and the binder are mixed in a mass ratio of 8:1:1 and dispersed in N-methylpyrrolidine. The tungsten oxide slurry is composed of ketones; the porous carbon-based counter electrode includes a porous carbon slurry and a current collector, the porous carbon slurry is coated on the surface of the current collector, wherein the current collector is graphite foil, forming a porous carbon-based counter electrode; the porous carbon slurry includes active material II, conductive agent and binder, wherein active material II is activated carbon, conductive agent is carbon black, and binder is polytetrafluoroethylene, active material II, conductive agent and binder are mixed in a mass ratio of 8:1:1 and dispersed in N,N-dimethylformamide to form a porous carbon slurry; after the tungsten oxide-based working electrode and the porous carbon-based counter electrode are assembled, an acidic electrolyte is added to obtain a capacitive ion diode.

[0033] like Figure 1 As shown, the tungsten oxide dihydrate material prepared using the material described in this embodiment has a microstructure of nanosheets with very uniform size and nanoscale interlayer spacing, providing space for ion storage and transport. Figure 4 The layered structure can also be observed further. For example... Figure 7As shown, further X-ray diffraction tests revealed that tungsten oxide dihydrate has a monoclinic crystal structure, which is a typical intercalated pseudocapacitor material. It can be seen that the water of crystallization in tungsten oxide dihydrate has a significant impact on its structure, which plays an important role in its ion transport dynamics and ion rectification capability.

[0034] Using the materials described in this embodiment, a tungsten oxide dihydrate-based electrode is used as the working electrode and assembled with an activated carbon counter electrode in the form of a sandwich battery. During the preparation process, sulfuric acid electrolyte is added dropwise, and the entire device is encapsulated with a sealing film to obtain a biocompatible tungsten oxide-based capacitive ion diode. Figure 12 , 15 As shown in Figures 18 and 21, the cyclic voltammetry and galvanostatic charge-discharge curves of this ion diode demonstrate a very significant ion sieving effect. The first-order rectification ratio of the tungsten oxide dihydrate electrode, calculated from the cyclic voltammetry curves, is as high as 220, and the second-order rectification ratio, calculated from the galvanostatic charge-discharge curves, is as high as 96.3%. These excellent ion rectification properties enable the capacitive ion diode assembled from the tungsten oxide monohydrate electrode to exhibit ideal unidirectional energy storage behavior; the device can charge and discharge normally under forward bias, while it can hardly store charge under reverse bias.

[0035] Example 2 Based on the nano-confined fluid-mediated capacitive ion diode of Example 1, by replacing the active material I with hydrated tungsten oxide while keeping the other materials and conditions unchanged, a capacitive ion diode is obtained.

[0036] like Figure 2 As shown, the hydrated tungsten oxide material prepared using the material described in this embodiment has a microstructure of nanosheets with very uniform size and nanoscale interlayer spacing, providing space for ion storage and transport. Figure 5 The layered structure can also be observed further. For example... Figure 8 As shown, further X-ray diffraction tests revealed that tungsten oxide monohydrate has an orthorhombic crystal structure, making it a typical intercalated pseudocapacitor material. Comparison shows that the water of crystallization in tungsten oxide monohydrate significantly influences its structure, playing a crucial role in its ion transport kinetics and ion rectification capabilities. From... Figure 10The cyclic voltammetry curves of the three electrode materials shown in the figure reveal that all three exhibit a significant ion sieving effect, exhibiting high charge storage current in the low potential range of -0.7 to 0.2 V, indicating efficient storage of hydrogen ions in the electrolyte. However, in the high potential range of 0.2 to 1.1 V, the hydrated tungsten oxide electrode shows only a very weak double-layer capacitance, indicating that sulfate ions in the electrolyte cannot be effectively stored within the tungsten oxide electrode due to the ion sieving effect. Figure 11 The comparison of the constant current charge-discharge curves of the three electrode materials shown indicates that the charge storage capacity of the tungsten oxide electrode is mainly concentrated in the low potential range where hydrogen ions contribute capacity. This phenomenon further demonstrates that the tungsten oxide electrode has good selective storage behavior for anions and cations in the electrolyte.

[0037] Using the materials described in this embodiment, the high-performance tungsten oxide monohydrate-based electrode is used as the working electrode and assembled with an activated carbon counter electrode in the form of a sandwich battery. During the preparation process, sulfuric acid electrolyte is added dropwise, and the entire device is encapsulated with a sealing film to obtain a biocompatible tungsten oxide monohydrate-based capacitive ion diode. Figure 13 , 16 As shown in Figures 19 and 22, the cyclic voltammetry and galvanostatic charge-discharge curves of this ion diode demonstrate a very significant ion sieving effect. The first-order rectification ratio of the hydrated tungsten oxide electrode, calculated from the cyclic voltammetry curves, is as high as 308, and the second-order rectification ratio, calculated from the galvanostatic charge-discharge curves, is as high as 99.2%. These excellent ion rectification properties enable the capacitive ion diode assembled from the hydrated tungsten oxide electrode to exhibit ideal unidirectional energy storage behavior; the device can charge and discharge normally under forward bias, while it can hardly store charge under reverse bias. Furthermore, as... Figure 24 , 25 As shown, this capacitive ion diode can operate efficiently and stably in classic AND and OR logic circuits, demonstrating good prospects for practical applications.

[0038] Example 3 To compare the implementation effects, anhydrous tungsten oxide-based capacitive ion diodes were further fabricated.

[0039] Based on the nano-confined fluid-mediated capacitive ion diode of Example 1, only the active material I is replaced with anhydrous tungsten oxide, while the other materials and conditions remain unchanged, to obtain a capacitive ion diode.

[0040] like Figure 3As shown, the anhydrous tungsten oxide material prepared using the material described in this embodiment has a microstructure of nanosheets with very uniform size and nanoscale interlayer spacing, providing space for ion storage and transport. Figure 6 Furthermore, its regular layered structure can be observed. For example... Figure 9 As shown, further X-ray diffraction testing revealed that anhydrous tungsten oxide has a monoclinic crystal structure, making it a typical intercalated pseudocapacitor material. From... Figure 10 The cyclic voltammetry curves of the three electrode materials shown in the figure reveal that all three exhibit a significant ion sieving effect, exhibiting high charge storage current in the low potential range of -0.7 to 0.2 V, indicating efficient storage of hydrogen ions in the electrolyte. However, in the high potential range of 0.2 to 1.1 V, the layered tungsten oxide electrode shows only a very weak double-layer capacitance, indicating that sulfate ions in the electrolyte cannot be effectively stored within the tungsten oxide electrode due to the ion sieving effect. Figure 11 The comparison of the constant current charge-discharge curves of the three electrode materials shown indicates that the charge storage capacity of the tungsten oxide electrode is mainly concentrated in the low potential range where hydrogen ions contribute capacity. This phenomenon further demonstrates that the tungsten oxide electrode has good selective storage behavior for anions and cations in the electrolyte.

[0041] Using the materials described in this embodiment, an anhydrous tungsten oxide-based electrode is used as the working electrode and assembled with an activated carbon counter electrode in the form of a sandwich cell. Sulfuric acid electrolyte is added dropwise during the preparation process, and the entire device is sealed with a sealing film to obtain a biocompatible tungsten oxide-based capacitive ion diode. Figure 14 , 17 As shown in Figures 20 and 23, the cyclic voltammetry and galvanostatic charge-discharge curves of this ion diode demonstrate a very significant ion sieving effect. The first-order rectification ratio of the hydrated tungsten oxide electrode, calculated from the cyclic voltammetry curves, is as high as 265, and the second-order rectification ratio, calculated from the galvanostatic charge-discharge curves, is as high as 98.4%. These excellent ion rectification properties enable the capacitive ion diode assembled from anhydrous tungsten oxide electrodes to exhibit ideal unidirectional energy storage behavior.

[0042] The comparison of the two electrochemical curves shows that the monohydrate tungsten oxide working electrode exhibits excellent electrochemical performance; that is, the monohydrate tungsten oxide with precise control of introducing one crystal water is the best performing electrode material among the three types of layered tungsten oxide.

[0043] Example 4 The fabrication method of the capacitive ion diode based on the nano-confined fluid-mediated ion diode in Example 2 is as follows: S1-1. Pretreatment of tungsten oxide dihydrate: Place tungsten oxide dihydrate powder in a 50 mL centrifuge tube, add anhydrous ethanol until the powder is completely submerged, and the liquid level is 2-3 cm above the powder layer. Place the centrifuge tube in a centrifuge and centrifuge at 2500 rpm for 10 min. After centrifugation, remove the centrifuge tube and slowly pour out the supernatant. The above steps constitute one cycle. Repeat the above cycle 3 times. After the last centrifugation, collect the tungsten oxide dihydrate at the bottom of the centrifuge tube and dry it at 60 °C for 4 h to obtain tungsten oxide dihydrate powder.

[0044] S1-2, Preparation of Tungsten Oxide Monohydrate: Based on the tungsten oxide dihydrate obtained in S1-1, the oven was started and the preheating temperature was set to 60℃. The tungsten oxide dihydrate powder obtained in step S1-1 was heated to 100℃ at a rate of 10℃ / min. After reaching 100℃, this temperature was maintained for drying for 2 hours. After drying, the heating system was turned off, and the air was blown at a rate of 20 m³ / h until the temperature inside the oven dropped to room temperature. The product was then removed, which is tungsten oxide monohydrate powder. The obtained tungsten oxide monohydrate powder was used as active material I and mixed with acetylene black and sodium alginate in a ratio of 7:2:1 and dispersed in deionized water to obtain tungsten oxide slurry. Then, the tungsten oxide slurry was uniformly coated on graphite foil, and the loading of active material was controlled at 2 mg / cm³. 2 The tungsten oxide-based working electrode was obtained by drying in a vacuum oven and cutting it.

[0045] S2. Using carbon nanotubes as active material II, and with the remaining materials the same as in step S1, prepare a porous carbon-based counter electrode, controlling the loading of the active material to be 5 mg / cm³. 2 .

[0046] S3. Using sulfuric acid solution as the electrolyte and deionized water as the solvent, a 0.1 mol / L electrolyte was prepared. In this electrolyte, H... + It can be efficiently stored in hydrated tungsten oxide materials, while SO4 2− Due to steric hindrance and electrostatic repulsion, tungsten oxide monohydrate cannot be stored in tungsten oxide materials, thus enabling tungsten oxide monohydrate to exhibit a significant cation-anion sieving effect.

[0047] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and carbon nanotube counter electrode in a sandwich battery manner, and add sulfuric acid electrolyte to it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode.

[0048] The hydrated tungsten oxide electrode prepared by the method described in this embodiment exhibits a very significant ion sieving effect in sulfuric acid electrolyte, meaning that the charge storage capacity of the hydrated tungsten oxide electrode is mainly concentrated in H+. + The low potential range contributes to the capacity, while in SO42− The high-potential range contributing to the capacity exhibits only a very weak double-layer capacitance. Calculations show that this hydrated tungsten oxide electrode achieves a first-order rectification ratio as high as 165 and a second-order rectification ratio as high as 96.8% in sulfuric acid electrolyte.

[0049] Example 5 The fabrication method of the nano-confined fluid-mediated capacitive ion diode based on Example 4 includes the following specific steps: S1. Based on the preparation method in step S1 of Example 4, hydrated tungsten oxide powder was prepared. The prepared hydrated tungsten oxide powder was mixed with acetylene black and sodium alginate at a ratio of 8:1:1 and dispersed in deionized water to obtain tungsten oxide slurry. Then, the tungsten oxide slurry was uniformly coated on graphite foil and the loading of active material was controlled to be 1 mg / cm³. 2 The tungsten oxide-based working electrode was obtained by drying in a vacuum oven and cutting it.

[0050] S2. Using carbon nanotubes as active material II, and with the remaining materials the same as in step S1, prepare a porous carbon-based counter electrode, controlling the loading of the active material to be 5 mg / cm³. 2 .

[0051] S3. Using sulfuric acid solution as the electrolyte and deionized water as the solvent, a 2 mol / L electrolyte was prepared. In this electrolyte, H... + It can be efficiently stored in hydrated tungsten oxide materials, while SO4 2− Due to steric hindrance and electrostatic repulsion, tungsten oxide monohydrate cannot be stored in tungsten oxide materials, thus enabling tungsten oxide monohydrate to exhibit a significant cation-anion sieving effect.

[0052] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and carbon nanotube-based counter electrode in the form of a button capacitor, and add sulfuric acid electrolyte to it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode.

[0053] The hydrated tungsten oxide electrode prepared by the method described in this embodiment exhibits a very significant ion sieving effect in sulfuric acid electrolyte, meaning that the charge storage capacity of the hydrated tungsten oxide electrode is mainly concentrated in H+. + The low potential range contributes to the capacity, while in SO4 2− The high-potential range contributing to the capacity exhibits only a very weak double-layer capacitance. Calculations show that this hydrated tungsten oxide electrode achieves a first-order rectification ratio of up to 198 and a second-order rectification ratio of up to 98.2% in sulfuric acid electrolyte.

[0054] Example 6 The fabrication method of the nano-confined fluid-mediated capacitive ion diode based on Example 4 includes the following specific steps: S1. Based on the preparation method in step S1 of Example 4, hydrated tungsten oxide powder was prepared. The prepared hydrated tungsten oxide powder was mixed with acetylene black and styrene-butadiene rubber at a ratio of 5:4:1 and dispersed in deionized water to obtain tungsten oxide slurry. Then, the tungsten oxide slurry was uniformly coated on gold sheets, and the loading of active material was controlled to be 2 mg / cm³. 2 The tungsten oxide-based working electrode was obtained by drying in a vacuum oven and cutting it.

[0055] S2. Polymer-derived carbon, conductive carbon black, and polytetrafluoroethylene were mixed and dispersed in ethanol at a ratio of 8:1:1 to obtain a porous carbon slurry. The porous carbon slurry was then uniformly coated onto nickel foam, and the loading of the active material was controlled to be 4 mg / cm³. 2 The tungsten oxide-based working electrode was obtained by drying in a vacuum oven and cutting it.

[0056] S3. A polyacrylic acid solution with a concentration of 0.2 mol / L was selected as the electrolyte. In this electrolyte, H... + It can be efficiently stored in tungsten oxide monohydrate, while polyacrylate ions cannot be stored in tungsten oxide monohydrate due to steric hindrance and electrostatic repulsion. Therefore, tungsten oxide monohydrate can exhibit a significant cation and anion sieving effect.

[0057] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and polymer-derived carbon counter electrode in the form of a soft-pack capacitor, and drop polyacrylic acid electrolyte into it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode.

[0058] The hydrated tungsten oxide electrode prepared by the method described in this embodiment exhibits a very significant ion sieving effect in polyacrylic acid electrolyte, meaning that the charge storage capacity of the hydrated tungsten oxide electrode is mainly concentrated in H+. + The electrode exhibits a very weak double-layer capacitance in the low potential range where the capacity is contributed, while in the high potential range where the capacity is contributed by polyacrylate ions. Calculations show that this hydrated tungsten oxide electrode achieves a first-order rectification ratio of up to 102 and a second-order rectification ratio of up to 95.2% in polyacrylate electrolyte.

[0059] Example 7 The fabrication method of the nano-confined fluid-mediated capacitive ion diode based on Example 4 includes the following specific steps: S1. Based on the preparation method in step S1 of Example 4, hydrated tungsten oxide powder is prepared. The prepared hydrated tungsten oxide powder is mixed with conductive carbon black and polyvinylidene fluoride at a ratio of 8:1:1 and dispersed in N-methylpyrrolidone to obtain tungsten oxide slurry. Then, the tungsten oxide slurry is uniformly coated on titanium foil, and the loading of active material is controlled to be 1 mg / cm³. 2The tungsten oxide-based working electrode was obtained by drying in a vacuum oven and cutting it.

[0060] S2. Activated carbon, carbon black, and polytetrafluoroethylene are mixed and dispersed in ethanol at a ratio of 8:1:1. The slurry is then uniformly coated onto titanium foil, with the loading of active material controlled at 2 mg / cm³. 2 The porous carbon-based counter electrode was obtained by drying in a vacuum oven and cutting.

[0061] S3. A biocompatible phosphoric acid solution with a concentration of 1 mol / L was selected as the electrolyte. In this electrolyte, H... + It can be efficiently stored in hydrated tungsten oxide materials, while PO4 3− Due to steric hindrance and electrostatic repulsion, tungsten oxide monohydrate cannot be stored in tungsten oxide materials, thus enabling tungsten oxide monohydrate to exhibit a significant cation-anion sieving effect.

[0062] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and carbon black counter electrode in the form of planar interdigitated electrodes, and drop phosphoric acid electrolyte into it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode.

[0063] The hydrated tungsten oxide electrode prepared by the method described in this embodiment exhibits a very significant ion sieving effect in sulfuric acid electrolyte, meaning that the charge storage capacity of the hydrated tungsten oxide electrode is mainly concentrated in H+. + The low potential range contributes to the capacity, while in PO4 3− The high-potential range contributing to the capacity exhibits only a very weak double-layer capacitance. Calculations show that this hydrated tungsten oxide electrode achieves a first-order rectification ratio as high as 195 and a second-order rectification ratio as high as 97.8% in sulfuric acid electrolyte. Furthermore, regarding biocompatibility, due to PO4... 3− These are ions that exist in the human body, laying a solid foundation for future human-computer interaction.

[0064] Example 8 The fabrication method of the nano-confined fluid-mediated capacitive ion diode based on Example 4 includes the following specific steps: S1. Based on the preparation method in step S1 of Example 4, hydrated tungsten oxide powder was prepared. The prepared hydrated tungsten oxide powder was mixed with conductive carbon black and polytetrafluoroethylene at a ratio of 6:3:1 and dispersed in ethanol to obtain tungsten oxide slurry. Then, the tungsten oxide slurry was uniformly coated on graphite foil, and the loading of active material was controlled to be 2 mg / cm³. 2 The tungsten oxide-based working electrode is obtained by drying in a forced-air drying oven and cutting it.

[0065] S2. Activated carbon, acetylene black, and polytetrafluoroethylene were mixed and dispersed in ethanol at a ratio of 8:1:1 to obtain a porous carbon slurry. The porous carbon slurry was then uniformly coated onto graphite foil, with the loading of active material controlled at 4 mg / cm³. 2 The porous carbon-based counter electrode was obtained by drying in a forced-air drying oven and cutting.

[0066] S3. Using sulfuric acid and phosphoric acid as electrolytes and deionized water as solvent, a mixed electrolyte of sulfuric acid and phosphoric acid with a concentration of 1 mol / L was prepared. This electrolyte contains only H+. + It can be efficiently stored in tungsten oxide monohydrate electrode, thus enabling the tungsten oxide monohydrate electrode to exhibit a significant cation and anion sieving effect.

[0067] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and activated carbon counter electrode in a sandwich battery manner, and add sulfuric acid-phosphoric acid mixed electrolyte to it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode.

[0068] The tungsten oxide monohydrate electrode prepared using the method described in this embodiment exhibits a significant ion sieving effect in a sulfuric acid-phosphoric acid mixed electrolyte. Specifically, it displays a high charge storage current in the low-potential range, while exhibiting only a very weak double-layer capacitance in the high-potential range. This indicates that sulfate ions in the electrolyte cannot be effectively stored within the tungsten oxide monohydrate electrode due to the ion sieving effect. Simultaneously, the charge storage capacity of the tungsten oxide monohydrate electrode is mainly concentrated in the low-potential range where hydrogen ions contribute capacity, further demonstrating the electrode's excellent selective storage behavior for anions and cations in the electrolyte. Calculations show that the tungsten oxide monohydrate electrode achieves a first-type rectification ratio as high as 161 and a second-type rectification ratio as high as 96.3% in the sulfuric acid-phosphoric acid mixed electrolyte. This results in a capacitive ion diode assembled from the tungsten oxide monohydrate electrode exhibiting ideal unidirectional energy storage behavior, which can be widely applied in technologies such as smart grids based on ion / electron coupling circuits, in vivo diagnostics, human-machine interfaces, and neural network interactions.

[0069] Example 9 The fabrication method of the nano-confined fluid-mediated capacitive ion diode based on Example 4 includes the following specific steps: S1. Based on the preparation method in step S1 of Example 4, hydrated tungsten oxide powder was prepared. The prepared hydrated tungsten oxide powder was mixed with conductive carbon black and polytetrafluoroethylene at a ratio of 8:1:1 and dispersed in ethanol to obtain tungsten oxide slurry. Then, the tungsten oxide slurry was uniformly coated on graphite foil and the loading of active material was controlled to be 1 mg / cm³. 2 The tungsten oxide-based working electrode is obtained by drying in a forced-air drying oven and cutting it.

[0070] S2. Activated carbon, conductive carbon black, and polytetrafluoroethylene are mixed and dispersed in ethanol at a ratio of 8:1:1 to obtain a porous carbon slurry. The porous carbon slurry is then uniformly coated onto a graphite foil, with the loading of the active material controlled at 10 mg / cm³. 2 The porous carbon-based counter electrode was obtained by drying in a forced-air drying oven and cutting.

[0071] S3. Using sulfuric acid as the electrolyte and deionized water as the solvent, sulfuric acid electrolytes of different concentrations were prepared by varying the ratios: 0.01 mol / L, 0.1 mol / L, 1 mol / L, and 10 mol / L. Among these four electrolytes, only H+ is present. + It can be efficiently stored in tungsten oxide monohydrate electrode, thus enabling the tungsten oxide monohydrate electrode to exhibit a significant cation and anion sieving effect.

[0072] S4. Assemble the above-mentioned hydrated tungsten oxide-based working electrode and activated carbon counter electrode in a sandwich battery manner, and add sulfuric acid electrolyte of different concentrations to it. Then, seal the entire device with a sealing film to obtain a hydrated tungsten oxide-based capacitive ion diode that works under different concentrations of electrolyte.

[0073] The tungsten oxide monohydrate electrode prepared using the method described in this embodiment exhibits the same ion sieving effect in four concentrations of sulfuric acid electrolyte. Specifically, it shows a high charge storage current in the low potential range, while exhibiting only a very weak double-layer capacitance in the high potential range. This indicates that sulfate ions in the electrolyte cannot be effectively stored within the tungsten oxide monohydrate electrode due to the ion sieving effect. The charge storage capacity of the tungsten oxide monohydrate electrode is mainly concentrated in the low potential range where hydrogen ions contribute capacity, further demonstrating the good selective storage behavior of the tungsten oxide monohydrate electrode for anions and cations in the electrolyte. Meanwhile, the hydrogen ion concentration varies in different concentrations of sulfuric acid electrolyte. Calculations show that the first-order rectification ratios of the tungsten oxide monohydrate electrode in 0.01 mol / L, 0.1 mol / L, 1 mol / L, and 10 mol / L sulfuric acid electrolytes are 12, 102, 202, and 48, respectively, and the second-order rectification ratios are 88%, 89%, 95.3%, and 65%, respectively. This demonstrates that capacitive ion diodes exhibit ideal unidirectional energy storage behavior in sulfuric acid electrolytes of different concentrations, and can be widely used in technologies such as smart grids based on ion / electron coupling circuits, in vivo diagnosis and treatment, human-machine interfaces, and neural network interaction.

[0074] In Examples 1, 2, and 3, tungsten oxide-based working electrodes were prepared using tungsten oxide dihydrate, tungsten oxide monohydrate, and anhydrous tungsten oxide, respectively. Comparison under the same electrolyte conditions directly reflects the influence of water of crystallization content on performance. Electrochemical curve comparison shows that all examples exhibit ion sieving effects, but the tungsten oxide monohydrate electrode in Example 2 demonstrates the best performance. The first-order rectification ratio of Example 2 is significantly higher than that of Examples 1 and 3, and the second-order rectification ratio also indicates that its unidirectional conduction characteristics are most significant. Examples 4-9 are all based on the tungsten oxide monohydrate-based electrode of Example 2, implementing different schemes by adjusting the proportions of other materials, electrolyte type, or concentration. However, compared to Examples 4-9, Example 2 has the highest first-order rectification ratio (308) and second-order rectification ratio (99.2%), significantly improving the unidirectional conduction characteristics of the ion diode.

Claims

1. A nano-confined fluid-mediated capacitive ion diode, characterized in that, The capacitive ion diode includes a tungsten oxide-based working electrode, a porous carbon-based counter electrode, and an acidic electrolyte. The tungsten oxide-based working electrode includes a tungsten oxide slurry and a current collector. The tungsten oxide slurry is coated on the surface of the current collector to form the tungsten oxide-based working electrode. The tungsten oxide slurry includes active material I, a conductive agent and a binder, wherein active material I is tungsten oxide dihydrate or tungsten oxide monohydrate, and the active material I, the conductive agent and the binder are mixed and dispersed in a dispersant to form the tungsten oxide slurry; The porous carbon-based counter electrode comprises a porous carbon slurry and a current collector, wherein the porous carbon slurry is coated on the surface of the current collector to form a porous carbon-based counter electrode. The porous carbon slurry comprises active material II, conductive agent and binder, wherein the active material II, conductive agent and binder are mixed and dispersed in a dispersant to form the porous carbon slurry; The tungsten oxide-based working electrode and the porous carbon-based counter electrode are assembled and then added to an acidic electrolyte to obtain a capacitive ion diode.

2. The nano-confined fluid-mediated capacitive ion diode according to claim 1, characterized in that, The mass ratio of active material I or active material II, conductive agent, and binder excluding the dispersant is 5-8:1-4:

1.

3. The nano-confined fluid-mediated capacitive ion diode according to claim 2, characterized in that, Active material II is a porous carbon material, which may include activated carbon, biomass carbon, polymer-derived carbon, organic small molecule-derived carbon, graphene, graphyne, or carbon nanotubes.

4. The nano-confined fluid-mediated capacitive ion diode according to claim 3, characterized in that, The electrolyte in the acidic electrolyte is one or more inorganic or organic acids, including hydrochloric acid, sulfuric acid, phosphoric acid, and perchloric acid, and the organic acids include acetic acid, alginic acid, citric acid, polyacrylic acid, and polystyrene sulfonic acid.

5. The nano-confined fluid-mediated capacitive ion diode according to claim 4, characterized in that, The conductive agent is conductive carbon black, Ketjen black, acetylene black, carbon nanotubes, graphene nanosheets, or graphite powder; the binder is polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, sodium carboxymethyl cellulose, polyacrylic acid, polyethylene oxide, styrene-butadiene rubber, or sodium alginate; the dispersant is deionized water, ethanol, ethylene glycol, acetone, acetonitrile, propylene carbonate, N-methylpyrrolidone, N,N-dimethylformamide, or dimethyl sulfoxide; the current collector is aluminum foil, copper foil, titanium foil, nickel foil, gold foil, platinum foil, stainless steel mesh, nickel foam, copper foam, graphite foil, carbon paper, or carbon cloth.

6. A method for fabricating a nano-confined fluid-mediated capacitive ion diode according to any one of claims 1-5, characterized in that, include: S1-1. Pretreatment of tungsten oxide dihydrate: Place tungsten oxide dihydrate powder in a centrifuge tube, add anhydrous ethanol until the powder is completely submerged, place the centrifuge tube in a centrifuge, and centrifuge at 2500 rpm for 10 min. After centrifugation, remove the centrifuge tube and slowly pour out the supernatant. The above steps constitute one cycle. Repeat the above cycle 3 times. After the last centrifugation, collect the tungsten oxide dihydrate at the bottom of the centrifuge tube and dry it at 60℃ for 4 h to obtain tungsten oxide dihydrate powder.

7. The method for fabricating a nano-confined fluid-mediated capacitive ion diode according to claim 6, characterized in that, Also includes: S1-2, Preparation of hydrated tungsten oxide: Based on the tungsten oxide dihydrate prepared by S1-1, the prepared tungsten oxide dihydrate was placed in an environment of 60°C, and then the temperature was increased to 100°C at a rate of 10°C / min. It was then dried by blowing air at 100°C for 2 hours. After 2 hours, the blowing air was continued until the temperature inside the chamber dropped to room temperature, thus obtaining tungsten oxide monohydrate powder.

8. The method for fabricating a nano-confined fluid-mediated capacitive ion diode according to claim 7, characterized in that, include: S1. Preparation of tungsten oxide-based working electrode: Based on the tungsten oxide dihydrate powder or tungsten oxide monohydrate powder prepared in S1-1 or S1-2, one of the tungsten oxide dihydrate powder or tungsten oxide monohydrate powder is used as active material I and weighed with conductive agent and binder in proportion, and then mixed with dispersant to obtain tungsten oxide slurry. The tungsten oxide slurry is uniformly coated on current collector, dried and cut to obtain tungsten oxide-based working electrode. S2. Preparation of porous carbon-based counter electrode: Porous carbon material is used as active material II and combined with conductive agent, binder and dispersant to obtain porous carbon slurry. The porous carbon slurry is uniformly coated on current collector, dried and cut to obtain porous carbon-based counter electrode. S3. Preparation of acidic electrolyte: Select inorganic or organic acid as electrolyte, add solvent to prepare an electrolyte with a concentration of 0.01-10 mol / L; S4. Preparation of capacitive ion diode: The tungsten oxide-based working electrode and the porous carbon-based counter electrode obtained in step S2 are assembled, and the electrolyte prepared in step S3 is injected into them. After encapsulation, a tungsten oxide-based capacitive ion diode is obtained.

9. The method for fabricating a nano-confined fluid-mediated capacitive ion diode according to claim 8, characterized in that, The tungsten oxide-based capacitive ion diodes described in S4 are in the form of button type, sandwich type, pouch type, or planar interdigitated type.

Images