An ion rectifying device based on heterojunction coupled ion electric conversion gradient and a preparation method thereof, and an ion circuit system

Abstract

The application discloses an ion rectifier based on heterojunction coupling ion-electron conversion gradient and a preparation method and an ion circuit system thereof, and belongs to the technical field of flexible electronic devices. The ion rectifier comprises an ion transmission channel, which is internally provided with a first ion-selective layer and a second ion-selective layer arranged in sequence along an ion transmission direction and having different ion selection characteristics to form an ion migration gradient; and a first electrode and a second electrode having different ion-electron conversion characteristics and located at two ends of the ion transmission channel to form a conversion efficiency gradient; and the direction of the ion migration gradient is configured in the same direction as the direction of the conversion efficiency gradient. The application cooperatively enhances forward ion transmission and significantly suppresses reverse ion transmission through the same-direction coupling of the double gradients, and effectively improves the rectification ratio and stability of the device.

Description

Technical Field

[0001] This invention belongs to the field of flexible electronic device technology, specifically relating to an ion rectifier device based on heterojunction coupling ionization conversion gradient, its fabrication method, and an ion circuit system. Background Technology

[0002] Ion diodes are functional devices capable of unidirectional conduction and reverse suppression of ion currents. They can be used in processes such as ion rectification, ion signal modulation, and energy conversion, and can further serve as basic units for ion circuits in fields such as flexible electronics, wearable sensing, biomimetic neuromorphic devices, and microfluidic analysis. However, existing ion diodes generally suffer from low rectification ratios in practical applications, typically manifested as large reverse leakage currents and insufficient ion transport selectivity. Especially in complex fluid environments such as liquids / gels, ion transport is more susceptible to interface effects, concentration gradients, and channel geometry than electron transport, thus limiting its rectification output capability. Therefore, obtaining ion diode structures with stable ion rectification characteristics and easy integration is of great significance for promoting the development of flexible ion device technology and related applications.

[0003] To address the aforementioned issues, several improvement schemes have been proposed in the prior art: First, by optimizing the geometry of the ion channel (such as cones, nanopores, gradient channels, etc.) to introduce transport differences; for example, patent CN105044170A employs a nanoparticle pipette / nanopore structure, whose internal pores are cone-shaped and form typical asymmetric nanopores, thereby utilizing geometric asymmetry to generate or modulate ion rectification behavior, but its disclosed rectification ratio is only about 2; Second, by modifying the channel surface charge or introducing functional groups to enhance ion selectivity; for example, patent CN110310754A loads amino or carboxyl functional groups on one side of an anodic alumina (AAO) porous membrane. The existing technologies utilize polystyrene microspheres / silica microspheres to construct a bilayer asymmetric structure. Rectification is achieved by controlling the surface charge distribution and ion selectivity through charged functional groups, but the rectification ratio remains primarily in the single digits (approximately 3.5–6.2). Thirdly, direction-dependent ion migration is achieved by constructing structural or material asymmetries (such as heterojunctions, asymmetric electrodes, or bilayer structures). For example, in patent CN108178119A, AAO is used as a substrate, and inorganic oxide films with different isoelectric points are deposited on both sides of the membrane, resulting in opposite charge distributions on both sides in solution. This creates material / interface charge asymmetry and generates an ion rectification effect, but the highest rectification ratio is only about 15.3. In summary, the existing technologies have not fundamentally solved the problem of low rectification ratios in ion diodes. Limitations remain in the magnitude of rectification improvement, stability, and repeatability, making it difficult for devices to achieve continuous and reliable high rectification output over a wide voltage range and under different electrolyte conditions.

[0004] Therefore, it is necessary to address the problem of low rectification ratio and difficulty in steadily improving existing ion diodes by providing an ion diode technology solution that can effectively enhance unidirectional ion transport and significantly suppress reverse ion leakage. This solution would enable the diode to achieve a higher rectification ratio and more reliable performance while ensuring device structural stability and repeatability. Furthermore, it would feature simple processing, easy integration, and suitability for flexible / large-area fabrication to meet the needs of ion circuits and emerging application scenarios. Summary of the Invention

[0005] This invention provides an ion rectifier device based on heterojunction coupling ionization conversion gradient, its fabrication method, and ion circuit system, which significantly improves the ion rectification performance of ion diodes and enables the device to achieve a higher rectification ratio and more reliable rectification output under a wider range of operating conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An ion rectification device based on a heterojunction coupled ionization conversion gradient includes an ion transport channel, a first electrode, and a second electrode. The ion transport channel contains a first ion-selective layer and a second ion-selective layer arranged sequentially along the ion transport direction. The first and second ion-selective layers have different ion selection characteristics to form an ion migration gradient within the ion transport channel. The first and second electrodes are located at opposite ends of the ion transport channel and have different ion-electron conversion characteristics to form a conversion efficiency gradient at the electrode-electrolyte interface. The direction of the ion migration gradient is aligned with the direction of the conversion efficiency gradient to synergistically enhance forward ion transport and suppress reverse ion transport.

[0008] In one implementation, the ion-to-electron conversion efficiency of the first electrode is lower than that of the second electrode; the first ion-selective layer is disposed close to the first electrode, and the second ion-selective layer is disposed close to the second electrode; under forward bias conditions, the direction in which ions migrate from the first ion-selective layer to the second ion-selective layer is consistent with the direction in which ions undergo ion-to-electron conversion to the second electrode.

[0009] In one embodiment, the first ion-selective layer and the second ion-selective layer are respectively a polyanionic electrolyte layer and a polycationic electrolyte layer; the polyanionic electrolyte layer and the polycationic electrolyte layer form a heterogeneous interface with opposite charges at the interface to construct an ionic double layer; preferably, a PSSNa / PDACl heterogeneous interface.

[0010] In one embodiment, the polycationic electrolyte layer comprises polydiallyldimethylammonium chloride, and the polyanionic electrolyte layer comprises sodium polystyrene sulfonate; the polycationic electrolyte layer and the polyanionic electrolyte layer further comprise a substrate material, the substrate material comprising at least one of bacterial cellulose or polyvinyl alcohol.

[0011] In one embodiment, the first electrode is a titanium electrode, and the second electrode is an MXene two-dimensional film electrode; the material of the MXene two-dimensional film electrode includes Ti3C2T. x MXene.

[0012] In one embodiment, the first ion-selective layer, the second ion-selective layer, and the second electrode are all self-supporting flexible thin films; the ion rectifier device as a whole has a sandwich-like layered stacked structure.

[0013] In one implementation, the surface Zeta potentials of the first ion-selective layer and the second ion-selective layer have opposite signs; and the absolute values ​​of the surface Zeta potentials of the first ion-selective layer and the second ion-selective layer increase with the increase of the internal polyelectrolyte concentration.

[0014] This invention also provides a method for fabricating an ion rectifier device based on a heterojunction coupled ionization conversion gradient, comprising the following steps:

[0015] Prepare a first ion-selective layer and a second ion-selective layer, such that the first ion-selective layer and the second ion-selective layer have different ion-selective properties;

[0016] Prepare a first electrode and a second electrode, such that the first electrode and the second electrode have different ion-electron conversion characteristics;

[0017] Following the principle that the direction of the ion migration gradient is aligned with the direction of the conversion efficiency gradient, the first electrode, the first ion selective layer, the second ion selective layer, and the second electrode are sequentially stacked and assembled to obtain the ion rectifier device.

[0018] The preparation of the first ion-selective layer and the second ion-selective layer in the above-described steps specifically includes the following steps: mixing the polyelectrolyte with the substrate solution, stirring on a track shaker, degassing under vacuum, and drying at a constant temperature to obtain the first ion-selective layer and the second ion-selective layer;

[0019] The preparation of the second electrode specifically includes the following steps: preparing an MXene two-dimensional membrane electrode as the second electrode by vacuum-assisted filtration and vacuum drying;

[0020] The assembly was carried out in a chemically inert environment by stacking the layers sequentially.

[0021] The present invention also provides an ion circuit system, including the above-mentioned ion rectifier device; the ion circuit system is a full-wave rectifier bridge circuit or a logic gate circuit, and the ion rectifier device is integrated into the ion circuit system as a basic unit.

[0022] Beneficial effects: This invention provides an ion rectifier device based on heterojunction coupled ionization conversion gradient, its fabrication method, and an ion circuit system, which have the following advantages compared with the prior art:

[0023] The ion rectifier device provided by this invention forms an ion migration gradient by constructing heterojunctions with different ion selectivity characteristics within the ion transport channel, and constructs a conversion efficiency gradient with different ion-electron conversion characteristics at the two electrode interfaces, and couples the two gradients in the same direction. Under forward bias, the ion migration gradient promotes the cross-interface transport of specific ions, while the high conversion efficiency electrode interface accelerates ion-electron conversion; the superposition of these two significantly enhances the forward current. Under reverse bias, ion return is suppressed by the ion heterojunction, and the low conversion efficiency electrode interface restricts charge transfer, forming a dual suppression mechanism for reverse current. This dual asymmetric mechanism coupled in the same direction overcomes the limitation of the single-mechanism rectification capability in existing technologies. This invention achieves a rectification ratio far higher than that of traditional structures and a lower reverse leakage current without increasing device complexity, providing a reliable basic device platform for high-performance flexible ion circuits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the structure and working mechanism of the ion rectifier device according to an embodiment of the present invention;

[0025] Figure 2 These are current-voltage characteristic curves of ion diodes with different structures according to embodiments of the present invention;

[0026] Figure 3 This is a diagram showing the electrostatic potential distribution of polyelectrolyte molecules according to an embodiment of the present invention;

[0027] Figure 4 This is a graph showing the change in zeta potential of the composite membrane as a function of concentration according to an embodiment of the present invention.

[0028] Figure 5 This is a diagram illustrating the coupling mechanism between the ion heterojunction and the ionization conversion gradient in an embodiment of the present invention.

[0029] Figure 6 This is a bar chart comparing the rectification ratios of different ion diode structures according to embodiments of the present invention;

[0030] Figure 7This is a schematic diagram of the full-wave rectifier bridge circuit structure according to an embodiment of the present invention;

[0031] Figure 8 This is a waveform diagram of the input and output voltage of the full-wave rectifier bridge circuit according to an embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of the logic gate circuit connection according to an embodiment of the present invention;

[0033] Figure 10 This is a waveform diagram of the input and output voltage of the logic gate circuit in an embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0035] Example 1:

[0036] like Figure 1 and Figure 5 As shown, this embodiment provides an ion rectification device, including an ion transport channel, a first electrode, and a second electrode. The ion transport channel contains a first ion-selective layer and a second ion-selective layer arranged sequentially along the ion transport direction. The first and second ion-selective layers have different ion selection characteristics to form an ion migration gradient within the ion transport channel. It should be understood that although the figure shows a planar layered stacked structure, in other embodiments, the ion transport channel can also be in the form of a porous membrane, a nanotube array, or a microfluidic channel, as long as the first and second ion-selective layers are asymmetrically distributed along the transport path.

[0037] The first and second electrodes are located at opposite ends of the ion transport channel, respectively. These electrodes possess different ion-to-electron conversion characteristics, creating a conversion efficiency gradient at the electrode-electrolyte interface. In this embodiment, the difference in ion-to-electron conversion characteristics refers to significant differences in the double-layer charging kinetics, ion adsorption capacity, or charge transfer impedance at the two electrode interfaces during the non-Radidatic process. More importantly, the direction of the ion migration gradient is aligned with the direction of the conversion efficiency gradient to synergistically enhance forward ion transport and suppress reverse ion transport.

[0038] Combination Figure 5As shown in the schematic diagram of the working mechanism, when a forward bias is applied, the ion migration gradient facilitates the smooth passage of charge carriers through the heterogeneous interface, ensuring they reach the high-conversion-efficiency electrode. At this point, the bulk transport advantage within the channel and the conversion advantage at the interface are superimposed, significantly reducing the forward conduction resistance. Conversely, when a reverse bias is applied, the ion migration gradient first exerts electrostatic repulsion or steric hindrance on the return migration of charge carriers. Even if a small number of ions overcome this resistance to reach the other end, the sluggish interface dynamics at that end, being a low-conversion-efficiency electrode, further limit current formation. This dual suppression mechanism compresses the reverse leakage current to an extremely low level. Through the co-coupling of these dual gradients, this invention overcomes the performance bottleneck of a single asymmetric mechanism, achieving an exponential increase in the rectification ratio.

[0039] Example 2

[0040] This embodiment provides a detailed description of the first electrode, the second electrode, the first ion-selective layer, and the second ion-selective layer, based on Embodiment 1.

[0041] The ion-electron conversion efficiency of the first electrode is lower than that of the second electrode; the first ion-selective layer is disposed close to the first electrode, and the second ion-selective layer is disposed close to the second electrode; under forward bias conditions, the direction in which ions migrate from the first ion-selective layer to the second ion-selective layer is consistent with the direction in which ions undergo ion-electron conversion to the second electrode.

[0042] This embodiment further defines the specific spatial matching relationship of the dual gradients; this specific hierarchical configuration is the basis for achieving synergistic coupling. Combined with... Figure 5 As shown in the working mechanism, when the device is in a forward bias state, the external electric field drives charge carriers from the first ion-selective layer through the heterojunction into the second ion-selective layer. The direction of this ion migration vector points precisely towards the second electrode, which has high ion-electron conversion efficiency. At this time, the ion transport advantage inside the channel and the charge conversion advantage at the interface are consistent in vector direction, forming a superimposed enhancement effect.

[0043] The first ion-selective layer and the second ion-selective layer are a polyanionic electrolyte layer and a polycationic electrolyte layer, respectively. The polyanionic electrolyte layer and the polycationic electrolyte layer form a heterogeneous interface with opposite charges at the interface to construct an ionic double layer. In this embodiment, the differentiation of ion-selective properties is specifically achieved by introducing polyelectrolyte materials with fixed-charge groups. For example, the polycationic electrolyte layer can be a polymer containing quaternary ammonium salt groups, pyridinium salt groups, or imidazole salt groups, whose fixed positive-charge groups on its backbone allow anions to pass through while repelling cations; the polyanionic electrolyte layer can be a polymer containing sulfonic acid groups, carboxylic acid groups, or phosphate groups, whose fixed negative-charge groups allow cations to pass through while repelling anions. It should be understood that although subsequent embodiments will use polydiallyldimethylammonium chloride and sodium polystyrene sulfonate as preferred examples, the present invention is not limited to this, and any polyelectrolyte system that can stably exist in a solid matrix and provide fixed charges of opposite polarities is applicable.

[0044] When these two polyelectrolyte layers with opposite charges come into close contact, a space charge region, or ionic double layer (IDL), is formed at the interface due to electrostatic interactions. This IDL contains a built-in local asymmetric electric field, causing ions of specific polarities to face a lower energy barrier when crossing the interface, while ions of opposite polarities are strongly electrostatically repelled. The charge polarity of this heterojunction interface forms a logical causal relationship with the efficiency gradient of the aforementioned electrodes: only when the polyanionic electrolyte layer is located on the side of the inefficient electrode and the polycationic electrolyte layer is located on the side of the efficient electrode (or adjusted accordingly based on the carrier type) can the direction of the built-in electric field of the heterojunction match the conversion kinetics direction of the electrode interface, thereby amplifying the initial weak rectification effect into a macroscopically high rectification ratio output. This binary binding design of structure and function effectively avoids performance fluctuations caused by arbitrary material selection, providing a foundation for stable device fabrication.

[0045] The surface Zeta potentials of the first and second ion-selective layers have opposite signs; and the absolute values ​​of the surface Zeta potentials of the first and second ion-selective layers increase with increasing internal polyelectrolyte concentration. Figure 3The molecular electrostatic potential distribution diagram revealed the microscopic origin of this macroscopic potential difference: the quaternary ammonium salt groups in the polydiallyldimethylammonium chloride (PDACl) molecule exhibit a significant positive potential region (blue), while the sulfonic acid groups in the sodium polystyrene sulfonate (PSSNa) molecule exhibit a significant negative potential region (red). When these two polyelectrolytes are loaded onto the substrate to form a composite film, the fixed charge properties of their surfaces are preserved. In actual tests, the PDACl@BC composite film exhibits a positive Zeta potential, while the PSSNa@BC composite film exhibits a negative Zeta potential. This opposite charge polarity allows the two films to form an ionic double layer (IDL) at the contact interface.

[0046] Furthermore, the absolute values ​​of the surface Zeta potentials of the first and second ion-selective layers increase with increasing internal polyelectrolyte concentration, combining... Figure 4 As shown in the Zeta potential curve, with the increase of polyelectrolyte concentration in BC dispersion, the positive potential of PDACl@BC membrane gradually increases from about 37 mV and tends to level off to about 52 mV, while the absolute value of negative potential of PSSNa@BC membrane also increases from about 21 mV to about 46 mV and then enters the saturation plateau period.

[0047] Example 3

[0048] This embodiment provides a method for fabricating an ion rectifier device, including the following steps:

[0049] Step S301: Prepare the second electrode (MXene two-dimensional film electrode). Use commercially available Ti3C2T at a concentration of 2 mg / ml. x A self-supported membrane was prepared from an MXene dispersion by vacuum-assisted filtration, followed by vacuum drying at 50-80℃ for 10-12 hours to obtain a self-supported flexible Ti3C2T membrane. x MXene thin film.

[0050] Step S302: Prepare the first ion-selective layer and the second ion-selective layer. In this embodiment, according to... Figure 1 The structural layout shown and the layer sequence matching principle determined in Example 2 are as follows: the first ion-selective layer near the first electrode (Ti) is a bacterial cellulose membrane (PSSNa@BC) modified with sodium polystyrene sulfonate (PSSNa), and the second ion-selective layer near the second electrode (MXene) is a bacterial cellulose membrane (PDACl@BC) modified with polydiallyl dimethyl ammonium chloride (PDACl). The specific preparation method is as follows:

[0051] 100 mg of PSSNa or PDACl powder was dissolved in 20 mL of a 3.2 mg / mL bacterial cellulose aqueous solution and stirred on a track shaker for 20 minutes at room temperature to ensure uniform dispersion. The mixture was then placed in a vacuum oven for degassing to eliminate internal air bubbles and ensure film density. Finally, the degassed slurry was poured into a petri dish and dried at 60 °C for 8 hours to obtain PSSNa@BC composite membranes and PDACl@BC composite membranes, respectively.

[0052] Step S303, Device Assembly. The Ti3C2MXene film, PDACl@BC film, PSSNa@BC film, and the titanium sheet used as the first electrode prepared above are cut into predetermined sizes (e.g., 1 cm × 1 cm), and then stacked sequentially in a chemically inert environment (such as a glove box or argon atmosphere) in the order of "titanium sheet / PSSNa@BC / PDACl@BC / MXene film" to form a structure as shown in Figure 303. Figure 1 The sandwich-like layered stacked structure is shown. The emphasis here on chemically inert assembly is to prevent oxidative degradation of the MXene material and interfacial contamination, ensuring the intrinsic conversion characteristics of the electrode-electrolyte interface are preserved. In this structure, the PSSNa@BC layer serves as the first ion-selective layer providing negative charge selectivity, and the PDACl@BC layer serves as the second ion-selective layer providing positive charge selectivity; the two form a heterojunction at the interface. The titanium sheet serves as the first electrode with low conversion efficiency, and the MXene film serves as the second electrode with high conversion efficiency, perfectly meeting the dual-gradient unidirectional configuration requirements described in Example 2.

[0053] The current-voltage (IV) characteristics of the ion rectifier device prepared according to this preferred embodiment were tested, and the results are as follows: Figure 2 As shown in the test data, within the ±6V scan voltage range, the device exhibits significant asymmetric conductivity: in the forward bias region (corresponding to the direction of ion migration from PSSNa@BC to PDACl@BC and flow towards the MXene electrode), the current increases linearly with the voltage, exhibiting low-impedance conduction characteristics; while in the reverse bias region, the current is effectively suppressed to an extremely low level (absolute value less than 0.03 mA), and no significant breakdown or leakage current surge occurs even at a -6V high voltage. Calculations show that the rectification ratio of this configuration can reach 10. 3The conversion efficiency is significantly higher than that of traditional single-mechanism devices. This superior performance stems from the precise co-coupling between the conversion efficiency gradient of the Ti / MXene electrode and the ion migration gradient of the PSSNa / PDACl heterojunction: in the forward direction, the built-in electric field of the heterojunction promotes ion transport across the interface, and ions are rapidly adsorbed and charge-converted upon reaching the MXene interface, with the two factors superimposed to enhance conductivity; in the reverse direction, the heterojunction forms a dual suppression barrier against returning ions. Therefore, the material combination and structural design used in this embodiment fully demonstrate the comprehensive advantages of the present invention in achieving high rectification ratio, low leakage current, and flexibility.

[0054] Example 4

[0055] This embodiment provides a method for fabricating an ion rectifier device:

[0056] Unlike Example 3, this example replaces bacterial cellulose (BC) with polyvinyl alcohol (PVA) as the substrate material, while the types of the first electrode, second electrode, and polyelectrolyte remain the same as in Example 3, i.e., a titanium electrode is used as the first electrode and a Ti3C2T electrode is used as the second electrode. x The MXene two-dimensional film electrode is used as the second electrode, and the first ion-selective layer and the second ion-selective layer are constructed with PSSNa and PDACl, respectively.

[0057] The fabrication process of the ion rectifier in this embodiment is similar to that in Example 3 in terms of overall flow, but there are adaptive adjustments to the composite film fabrication process to suit the characteristics of PVA material:

[0058] Step S401: Prepare the second electrode (MXene two-dimensional film electrode). The method is exactly the same as step S301 in Example 3, and will not be repeated here.

[0059] Step S402: Prepare the first and second ion-selective layers based on the PVA substrate. Dissolve 100 mg of PSSNa or PDACl powder in 20 mL of a 3.2 mg / mL polyvinyl alcohol aqueous solution, and stir on a track shaker for 20 minutes at room temperature to ensure thorough mixing. Transfer the homogenized solution to a vacuum oven and remove air bubbles by vacuum degassing. After removing air bubbles, pour the mixture into a petri dish and dry at 60°C for 8 hours to obtain PDACl@PVA composite films and PSSNa@PVA composite films, both exhibiting good flexibility and self-supporting properties.

[0060] Step S403, Device Assembly. The prepared Ti3C2T... xThe MXene film, PDACl@PVA film, PSSNa@PVA film, and titanium sheet are cut to a predetermined size and then stacked in a chemically inert environment in the order of "titanium sheet / PSSNa@PVA / PDACl@PVA / MXene film" to form a sandwich-like layered stacked structure.

[0061] Current-voltage characteristics of the ion rectifier device fabricated using this configuration were tested. The results showed that although the ion transport channel structure of the PVA substrate differs from that of bacterial cellulose, and the water content and swelling behavior of the PVA film may result in a slightly lower bulk ion conductivity than that of the bacterial cellulose substrate, the device still exhibits significant asymmetric conductivity and a clear rectification effect. Within the same test voltage range, although the forward conduction current is slightly lower than that of Example 3, the reverse leakage current is also effectively suppressed to an extremely low level, and the calculated rectification ratio remains at an order of magnitude sufficient to support ion circuit applications. This result strongly demonstrates that the core innovation of this invention lies in the structural design principle of "co-coupling of ion migration gradient and conversion efficiency gradient," rather than relying on a specific substrate material.

[0062] Example 5

[0063] This embodiment provides an ion circuit system, including the ion rectifier device as described in any of the foregoing embodiments. The ion circuit system is a full-wave rectifier bridge circuit or a logic gate circuit, with the ion rectifier device integrated as a basic unit within the ion circuit system. This embodiment aims to verify the functional integrity and performance advantages of the aforementioned ion rectifier device in system-level applications, demonstrating that it not only possesses excellent individual rectification characteristics but can also serve as a reliable basic building block to meet the needs of complex ion signal processing and energy management.

[0064] When the ion circuit system is configured as a full-wave rectifier bridge circuit, its topology is as follows: Figure 7 As shown. The four ion rectifier devices of the aforementioned embodiments are assembled in a bridge connection manner, that is, two devices are connected in series to form a branch, and the two branches are connected in parallel and respectively connected to the AC signal input terminal and the load resistor R. Under this configuration, regardless of whether the input signal is in the positive or negative half-cycle, there is always a pair of diagonal ion rectifier devices in the circuit that are in the forward conducting state, while the other pair is in the reverse cutoff state, thereby converting the bidirectional alternating ion current into a unidirectional pulsating output. Combined with Figure 8 As shown in the input and output voltage waveforms, when an AC square wave voltage signal is applied to the input terminal, a rectified output voltage with constant polarity is obtained across the load resistor R. It is worth noting that, thanks to the high 10 ion rectifier device used... 3With a rectification ratio on the order of magnitude and extremely low reverse leakage current, the output waveform exhibits minimal distortion near the zero-crossing point, and no significant voltage drop or leakage plateau occurs in the reverse cutoff region. This is significantly superior to rectifier bridges composed of traditional ion diodes. This full-wave rectification capability enables the ion circuit system to efficiently extract the DC component from environmental fluctuations or provide a stable charging current for subsequent ion energy storage units, solving the problem of low energy conversion efficiency caused by severe reverse leakage in existing ion energy harvesting systems.

[0065] As another alternative implementation, the ion circuit system can also be configured as a logic gate circuit. For example... Figure 9 In the logic gate circuit connection diagram shown, the two ion rectifier devices, together with the load resistor R and the ground terminal (GND), constitute a dual-input logic operation unit, with the input terminals being V... A With V B The output terminal is V out . Figure 10 The timing response curves of this logic gate circuit under dual-pulse input are shown, and the results indicate that the output Vout can accurately follow the input signal V. A With V B The logical combination changes achieve the expected logical operation function. More importantly, because the ion rectifier device of this invention has extremely high impedance and extremely low leakage current under reverse bias, the output voltage remains at a low level close to 0 V in the logic "0" state, avoiding logical misjudgment or noise interference caused by reverse leakage current, thereby significantly improving the noise margin and operational reliability of the ion logic circuit. This characteristic is crucial for constructing complex multi-stage cascaded ion processors or biomimetic neuromorphic computing arrays, ensuring that the signal will not degrade or be distorted due to accumulated leakage current during the stage-by-stage transmission.

[0066] This embodiment integrates the aforementioned high-performance ion rectifier into a full-wave rectifier bridge and logic gate circuits, fully demonstrating its engineering value in practical application scenarios and laying a solid device foundation for the practical application of flexible ion electronics technology.

[0067] Comparative Example

[0068] To further verify the synergistic enhancement effect produced by the co-directional configuration of the ion migration gradient and the conversion efficiency gradient in this invention, and to demonstrate the indispensability of this specific coupling relationship for achieving high rectification performance, three sets of comparative examples were set up for testing. These comparative examples represent the cases of gradient reverse coupling, the presence of only a single ion migration gradient, and the presence of only a single conversion efficiency gradient, respectively. By comparing with the preferred configuration in the aforementioned Example 3, the substantial features and significant progress of the technical solution of this invention are demonstrated from the opposite perspective.

[0069] Specifically, Comparative Example 1 employs a reverse-coupled device structure, where layers are stacked in the order of "Ti metal electrode / PDACl@BC film / PSSNa@BC film / MXene electrode". In this structure, although it also includes an ion heterojunction and an asymmetric electrode, the direction of the ion migration gradient is opposite to the direction of the conversion efficiency gradient. Specifically, the high-conversion-efficiency MXene electrode corresponds to the negatively charged PSSNa@BC layer, while the low-conversion-efficiency Ti electrode corresponds to the positively charged PDACl@BC layer. This inversion of the layer sequence means that under forward bias, although the MXene electrode possesses efficient ion-electron conversion capabilities, ions must overcome the electrostatic barrier at the PDACl / PSSNa heterojunction before entering the interface (because cations need to pass through the positively charged PDACl layer to reach the interface), severely inhibiting forward conduction. Under reverse bias, the built-in electric field of the heterojunction actually facilitates ion back migration. Furthermore, since the back migrating ions arrive at the inefficient Ti electrode, while this provides some restriction, an effective double barrier cannot be formed overall. Figure 6 As shown, the rectification ratio of Comparative Example 1 is only 10. 1 The magnitude of the reverse leakage current is significantly higher than that of Example 3, which fully demonstrates that if the gradient direction is mismatched, not only will synergistic effects not be produced, but performance may even be degraded.

[0070] Comparative Example 2 aims to examine the upper limit of performance achievable solely by relying on the ion migration gradient generated by the ion heterojunction. This comparative example uses symmetrical titanium electrodes with a PSSNa@BC / PDACl@BC heterojunction sandwiched in between, constructing a "Ti / PSSNa@BC / PDACl@BC / Ti" structure. Since the electrode materials at both ends are identical, their ion-electron conversion characteristics are consistent, and no conversion efficiency gradient exists. Test results show that the device does indeed exhibit some rectification behavior, confirming that the polyelectrolyte heterojunction itself can provide basic ion selectivity. However, as... Figure 2 Pink curve and Figure 6 The data shows that its rectification ratio is stable at 10. 1 Up to 10 2 Between, far lower than 10 in Example 3 3 The magnitude is significant. This is because, in the absence of an efficient conversion end, the forward ion current, after passing through the heterojunction, is limited by the slow double-layer charging kinetics of the Ti electrode and cannot be quickly discharged, resulting in a bulk accumulation effect that limits the maximum conduction current. At the same time, reverse suppression relies solely on the electrostatic repulsion of the heterojunction and lacks secondary blocking through interface kinetics, making it difficult to suppress the leakage current to an extremely low level.

[0071] Comparative Example 3 was used to evaluate the contribution of the conversion efficiency gradient generated solely by the asymmetric electrode to the rectification performance. This comparative example retained the Ti / MXene asymmetric electrode pair but removed the intermediate ion heterojunction, replacing it with a monolayer PSSNa@BC film (or a substrate film with no significant charge selectivity), thus constructing a "Ti / PSSNa@BC / MXene" structure. In this configuration, although the conversion efficiency difference at the electrode interface still exists, the lack of a directionally selective ion migration gradient within the channel means that ions are not directionally controlled during bulk transport. Figure 2 medium green curve and Figure 6 As shown, the rectification ratio of this device also remains at 10. 1 Up to 10 2 This indicates that while relying solely on the asymmetry of the electrode interface can modulate the interfacial impedance to some extent, it cannot fundamentally solve the problem of disordered diffusion of bulk ion current. Especially at higher voltages, the dominant role of bulk conductivity will rapidly weaken the rectification gain brought about by the interfacial effect.

[0072] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes, substitutions, improvements, or equivalent transformations made by those skilled in the art within the technical scope disclosed in the present invention, based on the core concept of the present invention, should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An ion rectifier device based on heterojunction coupled ionization conversion gradient, characterized in that, The device includes an ion transport channel, a first electrode, and a second electrode. The ion transport channel contains a first ion-selective layer and a second ion-selective layer arranged sequentially along the ion transport direction. The first and second ion-selective layers have different ion-selective characteristics to form an ion migration gradient within the ion transport channel. The first and second electrodes are located at opposite ends of the ion transport channel and have different ion-electron conversion characteristics to form a conversion efficiency gradient at the electrode-electrolyte interface. The direction of the ion migration gradient is aligned with the direction of the conversion efficiency gradient to synergistically enhance forward ion transport and suppress reverse ion transport.

2. The ion rectifier device based on heterojunction coupled ionization conversion gradient according to claim 1, characterized in that, The ion-electron conversion efficiency of the first electrode is lower than that of the second electrode; the first ion-selective layer is disposed close to the first electrode, and the second ion-selective layer is disposed close to the second electrode; under forward bias conditions, the direction in which ions migrate from the first ion-selective layer to the second ion-selective layer is consistent with the direction in which ions undergo ion-electron conversion to the second electrode.

3. The ion rectifier device based on heterojunction coupled ionization conversion gradient according to claim 1 or 2, characterized in that, The first ion-selective layer and the second ion-selective layer are a polyanionic electrolyte layer and a polycationic electrolyte layer, respectively; the polyanionic electrolyte layer and the polycationic electrolyte layer form a heterogeneous interface with opposite charges at the interface to construct an ionic double layer.

4. The ion rectifier device based on heterojunction coupled ionization conversion gradient according to claim 3, characterized in that, The polycationic electrolyte layer comprises polydiallyldimethylammonium chloride, and the polyanionic electrolyte layer comprises sodium polystyrene sulfonate; the polycationic electrolyte layer and the polyanionic electrolyte layer also comprise a substrate material.

5. The ion rectifier based on heterojunction coupled ionization conversion gradient according to claim 1 or 2, characterized in that, The first electrode is a titanium electrode, and the second electrode is an MXene two-dimensional film electrode.

6. The ion rectifier device based on heterojunction coupled ionization conversion gradient according to claim 1 or 2, characterized in that, The first ion-selective layer, the second ion-selective layer, and the second electrode are all self-supporting flexible thin films.

7. The method for fabricating the ion rectifier device based on heterojunction coupled ionization conversion gradient according to any one of claims 1-6, characterized in that, Includes the following steps: Prepare a first ion-selective layer and a second ion-selective layer, such that the first ion-selective layer and the second ion-selective layer have different ion-selective properties; Prepare a first electrode and a second electrode, such that the first electrode and the second electrode have different ion-electron conversion characteristics; Following the principle that the direction of the ion migration gradient is aligned with the direction of the conversion efficiency gradient, the first electrode, the first ion selective layer, the second ion selective layer, and the second electrode are sequentially stacked and assembled to obtain the ion rectifier device.

8. The method for fabricating an ion rectifier device based on heterojunction coupled ionization conversion gradient according to claim 7, characterized in that, The preparation of the first ion-selective layer and the second ion-selective layer specifically includes the following steps: mixing the polyelectrolyte with the substrate solution, stirring on a track shaker, degassing under vacuum and drying at a constant temperature to obtain the first ion-selective layer and the second ion-selective layer; The preparation of the second electrode specifically includes the following steps: preparing an MXene two-dimensional membrane electrode as the second electrode by vacuum-assisted filtration and vacuum drying.

9. An ion circuit system, characterized in that, Includes the ion rectifier device as described in any one of claims 1-6 or the ion rectifier device prepared by the method described in any one of claims 7-8.

10. The ion circuit system according to claim 9, characterized in that, The ion circuit system is a full-wave rectifier bridge circuit or a logic gate circuit, and the ion rectifier device is integrated into the ion circuit system as a basic unit.

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