Preparation method and application of integrated self-charging flexible supercapacitor for regulating aniline low-temperature in-situ polymerization based on graphene oxide

Abstract

A flexible supercapacitor is faced with the problem of interface dissociation between an electrode and a gel electrolyte for a long time. The problem can be effectively solved and the performance can be improved by growing an electrode material on the gel electrolyte in situ to form an integrated device. The invention successfully develops an in-situ polymerization strategy under slow reaction kinetics: graphene oxide (GO) is added into polyvinyl alcohol / sodium alginate-based hydrogel to realize oriented polymerization of aniline. PANI is accurately regulated and controlled to form a continuous porous structure by virtue of a pi-pi conjugation effect of GO and a polyaniline (PANI) aromatic ring and a hydrogen bond synergistic effect of GO and an amino group; meanwhile, the crystallinity of the material is remarkably improved through the slow polymerization effect. The surface specific capacity of the obtained PANI-LT-GO device reaches 102.51 mF cm <-2 > under the current density of 0.3 mA cm <-2 >, performance degradation is avoided under the deformation condition, and the rate characteristic and the cycling stability are synchronously and greatly improved. By embedding the piezoelectric polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) film into the hydrogel electrolyte, the flexible device successfully realizes a self-charging function and can be used as a stress sensor to monitor human body movement, and the excellent biocompatibility and the application potential in the field of wearable electronics of the flexible device are fully proved.

Description

Technical Field

[0001] The present invention relates to the field of flexible energy storage devices and wearable sensing technologies, and in particular to an integrated flexible supercapacitor based on graphene oxide (GO)-regulated low-temperature in-situ polymerization of aniline and its motion sensing application. Background Art

[0002] With the rapid development of society and technology, the demand for wearable electronic devices that can monitor human physiological signals in real time, such as pulse, respiration, and limb movement, has surged. Flexible self-charging supercapacitors, due to their ease of fabrication, low cost, and biocompatibility, have become an ideal solution for combining energy supply and sensing functions.

[0003] Traditional flexible supercapacitors utilize an "electrode / hydrogel electrolyte / electrode" sandwich structure. Although the hydrogel can withstand deformation, the electrode-electrolyte interface is susceptible to dissociation under repeated bending / torsion, resulting in: a sharp increase in contact resistance; significant capacity degradation; and degraded cycling stability. Existing solutions and their limitations include:

[0004] Integrated structure strategy: By in situ growing conductive polymers (such as polypyrrole PPy) on the surface of hydrogel to construct an integrated device, although it can improve flexibility and capacitance, it still has key drawbacks:

[0005] (1) Difficulty in polymerization control: High-temperature polymerization causes excessive aggregation of conductive polymers (such as polyaniline (PANI)), forming a loose granular structure and cracks at the interface;

[0006] (2) Insufficient crystallinity: Rapid polymerization inhibits the orderly arrangement of molecular chains, reducing conductivity and ion mobility.

[0007] Piezoelectric integration technology: Combining piezoelectric films (such as PVDF-TrFE) with supercapacitors can achieve self-powered sensing, but the piezoelectric layer blocks ion channels, resulting in a surge in internal resistance.

[0008] In view of the above defects, it is urgent to develop an integrated flexible supercapacitor with stable interface bonding, orderly structure and piezoelectric compatibility:

[0009] (1) Interface strengthening: chemical bonding between the electrode material and the hydrogel is required to avoid physical adhesion failure;

[0010] (2) Polymerization control: The polymerization kinetics must be precisely controlled to improve the crystallinity and loading of PANI;

[0011] (3) Piezoelectric integration optimization: The problem of the piezoelectric layer blocking ion migration needs to be solved. Summary of the Invention

[0012] In response to the shortcomings of the existing technology, the present invention provides an integrated flexible supercapacitor based on GO-induced in situ polymerization and a preparation method thereof, which significantly improves the electrochemical performance and mechanical stability of the device by regulating the polymerization kinetics and interfacial interactions.

[0013] The supercapacitor includes: a PVA / SA-based hydrogel electrolyte (containing a MoS2 reinforcement component); a GO-induced in-situ polymerized PANI electrode: a continuous worm-like porous PANI structure (thickness ≥ 60 μm) is formed on the gel surface through π-π interactions and hydrogen bonds, realizing electrode / electrolyte integration; and an embedded PVDF-TrFE piezoelectric film: a perforated design gives the device self-charging and pressure sensing functions.

[0014] The preparation method comprises the following steps:

[0015] 1. Hydrogel preparation: 3.0 g of polyvinyl alcohol (PVA), 0.15 g of sodium alginate (SA), 0.95 ml of sulfuric acid (H2SO4), and 3 ml of polyethylene glycol (PEG) were added to 18 g of distilled water. The mixture was then stirred and heated at 95°C for 3 hours and allowed to stand for 1 hour to eliminate bubbles. The resulting solution was then transferred to a mold, placed at -15°C for 12 hours, and then thawed at 25°C and 50% relative humidity for 12 hours.

[0016] 2. In situ polymerization of PANI: The hydrogel was immersed in a 0.5 M aniline hydrochloride solution containing GO (5 mg / mL) for 15 minutes. An equal amount of 0.5 M ammonium persulfate (APS) solution was added dropwise and reacted in an ice bath at -10°C for 14 hours. After washing with deionized water (DI water), the PANI-LT-GO integrated electrode was obtained.

[0017] 3. Integrated piezoelectric layer: Embed a pre-punched PVDF-TrFE film in the gel electrolyte. The specific steps are: spread the PVA / SA-based hydrogel electrolyte solution prepared above in a culture dish, freeze it at -15°C for 3 hours and then take it out. Stick the punched PVDF-TrFE film tightly to the colloid surface in the culture dish, cover it with an equal amount of PVA-based aqueous solution, and refrigerate it again at -15°C for 12 hours. After taking it out, place it at 25°C and 50% humidity for 12 hours. After cutting, a gel electrolyte membrane containing a piezoelectric film is obtained, and a PANI electrode is in situ polymerized on the surface.

[0018] Advantages achieved through the above approach include:

[0019] 1. Enhanced interface bonding: The π-π interaction and hydrogen bonding of GO promote the uniform growth of PANI on the gel surface, eliminating the interfacial gap and reducing the contact resistance.

[0020] 2. Improved electrochemical performance: High specific capacity: 102.51mF / cm2 (0.3mA / cm 2 ); Excellent rate performance: current density increased to 2mA / cm 2 The capacity retention rate is 86.7%; long cycle stability: the capacity is retained at 80% after 3000 cycles.

[0021] 3. Mechanical stability: No capacitance loss when bent to 60°.

[0022] 4. Self-charging and sensing function: Finger bending (1Hz) can be charged to 0.5V; pressure sensing linear response (R 2 =0.9862), which is suitable for human motion monitoring.

[0023] The supercapacitor can be integrated into wearable devices to monitor physiological signals such as joint bending and respiratory rate in real time, and provide energy for IoT microdevices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required for describing the embodiments. It should be noted that these drawings are only examples of some embodiments of this application, and those skilled in the art can derive more content based on these drawings without creative work.

[0025] Figure 1 This is the synthesis mechanism diagram of the integrated flexible supercapacitor described in the present invention

[0026] Figure 2 ab are the surface and cross-sectional SEM images of the PANI-LT-GO integrated flexible device.

[0027] Figure 2 cd are the surface and cross-sectional SEM images of the PANI-RT integrated flexible device.

[0028] Figure 2 ef is the SEM image of the surface and cross section of the PANI-LT integrated flexible device

[0029] Figure 2 gh is the SEM image of the surface and cross section of the PANI-LT-AC integrated flexible device

[0030] Figure 2 i is the XRD pattern of different integrated flexible devices

[0031] Figure 2 j is the FT-IR image of different integrated flexible devices

[0032] Figure 3 a is the cyclic voltammetry (CV) curve image of different devices at a scan rate of 50 mV / s

[0033] Figure 3 b is the calculated rate performance image of different devices

[0034] Figure 3 c is the electrochemical impedance spectroscopy (EIS) image of different devices

[0035] Figure 3 d is the current of different devices at 0.5 mA·cm -2 Capacitance retention image after 3000 charge-discharge cycles at different current densities

[0036] Figure 3 e is the impedance fitting results of different devices

[0037] Figure 3 f is the cyclic voltammetry (CV) curve image of PANI-LT-GO device

[0038] Figure 3 g is the constant current charge and discharge (GCD) curve image of PANI-LT-GO device at different current densities

[0039] Figure 3 h is the cyclic voltammetry (CV) curve image of a single device and multiple devices in series / parallel

[0040] Figure 3 i is the cyclic voltammetry (CV) curve image of PANI-LT-GO device at different bending angles

[0041] Figure 3 j is the optical photograph of the PANI-LT-GO device at different bending angles on the flexibility tester

[0042] Figure 4 a is a schematic diagram of the structure of the prepared PANI-LT-GO device

[0043] Figure 4 b is the optical photograph of the prepared PANI-LT-GO device

[0044] Figure 4 c is the cyclic voltammetry (CV) curve image of the PANI-LT-GO integrated supercapacitor with a piezoelectric diaphragm

[0045] Figure 4 d is the constant current charge and discharge (GCD) curve image of the PANI-LT-GO integrated supercapacitor with piezoelectric diaphragm at different current densities

[0046] Figure 4 e is the electrochemical impedance spectroscopy (EIS) image of PANI-LT-GO device

[0047] Figure 4fg is the self-charging and sensing performance image of the PANI-LT-GO device at a frequency of 0.2 Hz and an angle of 60°.

[0048] Figure 4 h is the different electrical signal images generated by the PANI-LT-GO device under different pressure levels.

[0049] Figure 5 ab are SEM images of the surface and cross section of the hydrogel

[0050] Figure 6 Raman test images of different devices

[0051] Figure 7 a is the cyclic voltammetry (CV) curve image of PANI-LT device

[0052] Figure 7 b is the constant current charge and discharge (GCD) curve image of the PANI-LT device

[0053] Figure 7 c is the cyclic voltammetry (CV) curve image of the PANI-RT device

[0054] Figure 7 d is the constant current charge and discharge (GCD) curve image of the PANI-RT device

[0055] Figure 7 e is the cyclic voltammetry (CV) curve image of the PANI-LT-AC device

[0056] Figure 7 f is the constant current charge and discharge (GCD) curve image of the PANI-LT-AC device

[0057] Figure 8 ab is an image of the device working at the knuckles

[0058] Figure 9 Specific capacitance and Coulomb efficiency images of integrated devices

[0059] Figure 10 Image of the sensing and self-charging characteristics of the integrated sensing device

[0060] Figure 11 Impedance fitting data diagram of sensor device DETAILED DESCRIPTION

[0061] This section will provide a clear and complete description of the technical solutions proposed in this application in conjunction with the embodiments in the accompanying drawings. It should be noted that the listed embodiments are only some examples and do not constitute an exhaustive list of all implementation methods of this application. Based on the embodiments disclosed in this application, any other embodiments that can be obtained by any person of ordinary skill in the art without performing creative work are all included in the scope of protection of this application. In order to more clearly illustrate the technical solutions of this application and its advantages, a more detailed description is provided below in conjunction with the accompanying drawings.

[0062] In a first aspect, the present application provides a method for preparing an integrated supercapacitor based on a multi-network hydrogel, the specific preparation method comprising:

[0063] To prepare the hydrogel, 3.0 g of polyvinyl alcohol (PVA), 0.15 g of sodium alginate (SA), 0.95 ml of sulfuric acid (H2SO4), and 3 ml of polyethylene glycol (PEG) were added to 18 g of distilled water. The mixture was then stirred and heated at 95°C for 3 hours, then allowed to stand for 1 hour to eliminate air bubbles. The resulting solution was then transferred to a mold, stored at -15°C for 12 hours, and then thawed at 25°C and 50% relative humidity for 12 hours.

[0064] GO-induced low-temperature in situ polymerization: The hydrogel was immersed in a 0.5 M aniline hydrochloride solution containing 5 mg / mL GO for 15 min; an equal amount of 0.5 M ammonium persulfate (APS) solution was added dropwise in a -10°C ice bath for ≥14 h to allow aniline to polymerize into a continuous porous PANI electrode under the regulation of GO.

[0065] The preparation of the integrated flexible device follows Figure 1 The in situ polymerization of polyaniline (PANI) was achieved by immersing the hydrogel in an aqueous solution of aniline hydrochloride containing ammonium persulfate (APS) as an initiator. Experiments conducted under different conditions showed that the PANI generated on the surface of the hydrogel electrolyte showed significant morphological differences (such as Figure 1 and Figure 2 The original surface of the hydrogel was smooth ( Figure 5 ), and after adding graphene oxide (GO) for in situ polymerization under low temperature conditions, the active material is embedded in the hydrogel (e.g. Figure 1 The close interface between PANI and the hydrogel further demonstrates the ideal in situ polymerization of aniline and the successful fabrication of an all-in-one flexible device with low interfacial resistance.

[0066] Figure 2Figures ab show the surface and cross-sectional morphologies of PANI-LT-GO. Aniline monomers polymerize into a continuous worm-like structure. Studies have shown that the π-π interaction between PANI molecular chains and GO regulates the arrangement of PANI chains, while the hydrogen bonding between GO surface functional groups and PANI amino groups further promotes the formation of a continuous porous structure. This unique porous structure ensures rapid ion migration, while the continuous worm-like morphology improves electronic conductivity. In addition, cross-sectional SEM images show that PANI exists on the hydrogel surface as a uniform covering layer with a thickness of more than 60 μm.

[0067] For comparison, we also carried out in situ polymerization of aniline monomer at room temperature. The scanning electron microscope (SEM) image of the generated polyaniline (PANI-RT) is shown in Figure 2. Figure 2 As shown in Figure ef, polyaniline particles of uneven thickness and loose aggregation can be observed on the hydrogel. Furthermore, significant gaps exist at the interface between the polyaniline and the hydrogel electrolyte. This discontinuous interface typically leads to high contact resistance between the active material and the electrolyte. This undesirable in situ polymerization may be due to the higher temperature accelerating the polymerization reaction, resulting in the formation of large polyaniline aggregates.

[0068] To further understand the role of temperature and graphene oxide (GO), we carried out polymerization at a lower temperature of -10 °C without adding GO, and the obtained product (PANI-LT) is shown in Figure 2 As shown in Figure 3, compared to PANI-RT, aniline polymerizes into a porous structure composed of much smaller, uniform particles. Furthermore, the increased thickness of the polyaniline layer on the hydrogel further demonstrates that lowering the temperature helps increase the loading of the active material. However, without the assistance of GO, polyaniline does not exhibit the desired continuous porous structure; instead, the curled polyaniline chains likely result in a granular morphology.

[0069] We used activated carbon (AC) instead of GO to prepare PANI-AC-LT, and its morphology is as follows Figure 2 The thickness of the polyaniline layer in this sample is less than 20 micrometers (μm), which is thinner than that of PANI-LT, indicating that the activated carbon inhibits the in situ polymerization and further confirms that GO is the main influencing factor for achieving ideal in situ polymerization.

[0070] Therefore, we can conclude that lowering the polymerization temperature and adding GO are the two main reasons for achieving the ideal integrated device. The lower temperature prevents excessive acceleration of the polymerization reaction, allowing the polyaniline to be evenly distributed on the hydrogel. Furthermore, GO guides the polymerization reaction through π-π interactions with aniline, prompting the polyaniline chains to form a worm-like structure rather than aggregate into granules. Furthermore, the functional groups on GO can form hydrogen bonds with the hydrogel, contributing to the formation of a tight interface.

[0071] To further evaluate the PANI electrode on the hydrogel electrolyte, XRD and FTIR tests were performed, and the results are shown in Figure 2. Figure 2 i and 2j. The strong peaks at 15° and 45° are associated with MoS2 in the hydrogel, while the broad peak with the top at 20° is associated with the (111) peak of PVA. PANI-RT shows the same peaks as the hydrogel, indicating that the amount of PANI loaded on the hydrogel is small and amorphous, which is consistent with the SEM results. However, PANI-LT and PANI-LT-GO show additional peaks at about 14° and 18°, which are attributed to crystalline PANI generated at low temperature. PANI-LT-AC only shows a weak hydrogel electrolyte signal peak; considering its thin PANI layer, it is unlikely that the hydrogel signal is covered. One possible explanation is that AC may have destroyed the hydrogel polymer chains. Figure 6 The Raman spectroscopy results shown are consistent with the XRD results.

[0072] Figure 2 j shows the results of ATR-FTIR. Similar to XRD, the spectra of PANI-LT and PANI-LT-GO are almost the same. It is worth noting that due to the high PANI loading on the electrode surface, their spectra are in the range of 3000 to 3600 cm -1 There is no water adsorption band in the range. In addition, PANI-LT-GO and PANI-LT have a band of about 1400 cm -1 The CN stretching peaks at both ends are very weak; this may be mainly due to the high degree of polymerization of the PANI, which weakens the CN stretching peak intensity. This is consistent with the XRD results that PANI-LT and PANI-LT-GO are crystalline. Although PANI-RT, with a PANI layer thickness exceeding 40 μm, also shows a weak water adsorption band, it has a clear CN peak. PANI-LT-AC shows both clear water adsorption and CN peaks, indicating that the degree of polymerization of the aniline monomer in its PANI layer is low and the PANI layer is thin.

[0073] The electrochemical characterization results of devices prepared under different conditions are shown in Figure 3 and Figure 7As expected, PANI-LT-GO showed the best performance. The area of ​​its CV curve was significantly larger than that of the other comparison samples. Except for PANI-LT-AC, the constant current charge-discharge curves (GCD) of all devices showed a triangular profile, which is consistent with the pseudocapacitive behavior of the PANI electrode. It is worth noting that thanks to the close interface formed between PANI and the hydrogel, the internal resistance drop (IRdrop) of PANI-LT-GO is the smallest. As expected, the rate performance of PANI-LT-GO is particularly better than that of PANI-LT, PANI-RT and PANI-LT-AC. Figure 3 As shown in b, when the current density is increased from 0.3 mA cm -2 Increase to 1mAcm -2 When , the capacity retention rates of PANI-LT-GO, PANI-LT, PANI-RT and PANI-LT-AC are 91.8%, 48.1%, 17.3% and 4.3%, respectively.

[0074] The charge transfer behavior of all single-structure devices was further evaluated by electrochemical impedance spectroscopy (EIS) test. Figure 3 c and Figure 11 As shown in Figure 3, PANI-LT-GO has the lowest Re and Rs values. Furthermore, the diffusion zone, indicated by a straight line with a slope of approximately 1, is almost negligible, indicating rapid ion migration within the electrode due to its porous structure. However, PANI-RT exhibits a sharp increase in Rs due to its loose PANI particle stacking and discontinuous interface between the active material and the hydrogel electrolyte, coupled with a sluggish mass transport process.

[0075] The cycling stability of the four devices is shown in Figure 2. Figure 3 As expected, PANI-LT-GO also exhibits the best cycling stability. After 3000 cycles, its capacity still reaches 80% of its initial value, which is much higher than that of other comparative devices. We believe that the rapid capacity decay of other devices may be due to the dissociation of PANI from the hydrogel. Notably, the increase in capacity during the initial cycle of PANI-LT-GO and PANI-RT can be attributed to the wetting and activation process of the PANI electrode. However, the activation rate of the PANI electrode in the PANI-LT-GO device is much faster, which further supports the conclusion that its rapid ion migration is related to the PANI electrode.

[0076] According to the characterization results, the loading amount, crystallinity and degree of polymerization of PANI in PANI-LT and PANI-LT-GO are similar, but their performance (especially in terms of rate performance and cycle stability) is significantly different. We believe that the most likely reason is related to the continuous porous structure of PANI induced by graphene oxide (GO) and the improved interfacial contact between PANI / hydrogel (which reduces the internal resistance of the device). The addition of GO also contributes to the uniform distribution of PANI on the hydrogel electrolyte and promotes the stable performance of PANI-LT-GO in the integration of multiple devices. Figure 3 As shown in Figure f, two parallel devices double the potential window without changing the charge and discharge time, while two series devices double the charge and discharge time without changing the potential window. In addition, the dense interface between PANI and hydrogel inside the PANI-LT-GO device gives it significant tolerance under deformation conditions. Figure 3 As shown in Figure g, the cyclic voltammetry (CV) curve area of ​​the device at different bending angles remains almost unchanged, indicating that the device has excellent flexibility.

[0077] In the second aspect, the present invention provides a preparation scheme for a piezoelectric integrated device capable of realizing self-powered sensing. The specific preparation method is as follows: through-hole piezoelectric film integration: a through-hole structure with a pore size of 1 mm2 and a density of ≥4 pores / cm2 is prepared on a PVDF-TrFE film;

[0078] Layered assembly: A perforated film was sandwiched between two layers of PVA / SA hydrogel. The prepared PVA / SA-based hydrogel electrolyte solution was spread in a Petri dish and refrigerated at -15°C for 3 hours. A perforated PVDF-TrFE film was then tightly attached to the colloid surface in the dish. This was covered with an equal amount of PVA-based aqueous solution and refrigerated again at -15°C for 12 hours. After removal, the film was placed under 25% to 50% humidity for 12 hours and then cut to obtain a gel electrolyte membrane containing a piezoelectric film. Electrodes were in situ grown on the membrane surface using the same process used to prepare PANI-LT-GO. After trimming the edges, a motion sensor with a self-charging effect was obtained.

[0079] Supercapacitors with excellent rate performance and flexibility can be combined with piezoelectric films to be used as self-charging devices or motion sensors. Therefore, PANI-LT-GO is an ideal candidate material. In this paper, a PVDF-TrFE film with piezoelectric properties is sandwiched between the PANI-LT-GO device to achieve self-charging and sensor properties. The structure and photo of the device are shown in Figure 2. Figure 8As shown in ab, the device is named PANI-LT-GO-PVDF. The PVDF-TrFE film is perforated to facilitate ion transport. The cyclic voltammetry (CV) curve and constant current charge-discharge (GCD) curve of the device show that although its internal resistance has increased (which is explained by the voltage drop (IRdrop) in GCD and electrochemical impedance spectroscopy (EIS) results), its energy storage performance is not significantly affected. Figure 9 As shown, at 0.2mAcm -2 At a current density of 1.5 GHz, the device's specific capacitance is 68.4 mF cm -2 However, when the current density increases to 1 mA cm -2 When the device's specific capacitance drops to 40.8mFcm -2 .

[0080] The self-charging behavior is Figure 10 To demonstrate its performance as a self-charging sensor, we attached the device to a finger and measured its voltage change during finger movement. At a 1Hz bending frequency and a 60-degree bending angle, the device can charge to 0.5V and maintain a voltage of 0.3V even after the external force is removed. Figure 4 e demonstrates the device's motion sensing capabilities—each bend generates a clear pulse signal. Figure 4 As shown in f, the pulse amplitude is proportional to the vertical force applied to the device surface (R 2 The value is 0.9862), indicating that the linear response characteristics of potential to pressure are excellent.

[0081] In summary, the present invention successfully utilizes the in-situ polymerization reaction of aniline on the hydrogel electrolyte to prepare a PANI-LT-GO integrated flexible supercapacitor. Thanks to the synergistic effect of xx interaction and hydrogen bonding, the polymerization reaction induced by graphene oxide generates crystalline polyaniline with a continuous porous structure under the condition of reducing the reaction kinetics, which significantly improves the ion migration rate and electronic conductivity, while achieving high active material loading and close interface contact. The uniform distribution and sufficient growth of the electrode material effectively improve the electrochemical performance of the device. Therefore, the PANI-LT-GO device has a high capacitance at 0.3 mA cm -2 The current density was 103.51mFcm -2 The area specific capacitance at 2mAcm -2 Maintaining 84.6mFcm at a current density -2 These results demonstrate that the optimized assembly of PVDF-TrFE and PANI-LT-GO devices, combined with the close contact interface formed by the dense in situ growth of polyaniline on the hydrogel surface, can successfully fabricate a self-charging, all-in-one flexible supercapacitor with sensing behavior.

Claims

1. A method for preparing an integrated flexible supercapacitor, characterized in that The following steps are involved: (1) Preparation of polyvinyl alcohol / sodium alginate (PVA / SA)-based hydrogel electrolyte; (2) Soaking the hydrogel in a solution containing 0.5 M aniline hydrochloride and graphene oxide (GO) with a GO concentration of 5 mg / mL for 15 min; (3) under low temperature conditions of -10°C to 0°C, an equimolar amount of ammonium persulfate (APS) solution is added dropwise to initiate in situ polymerization of aniline, with a reaction time of ≥14 hours; (4) Surface impurities were rinsed with deionized water (DI water) to obtain a supercapacitor with an integrated PANI-LT-GO electrode-electrolyte structure.

2. The method according to claim 1, wherein: GO and aniline monomers guide polyaniline (PANI) to form a continuous porous structure through π-π interactions, and the oxygen-containing functional groups of GO form hydrogen bonds with the hydrogel and PANI amino groups.

3. The method according to claim 1, wherein: The preparation of the hydrogel comprises: 3.0 g of polyvinyl alcohol (PVA), 0.15 g of sodium alginate (SA), 0.95 ml of sulfuric acid (H2SO4), and 3 ml of polyethylene glycol (PEG) were added to 18 g of distilled water. The mixture was then stirred and heated at 95°C for 3 hours, then allowed to stand for 1 hour to eliminate air bubbles. The resulting solution was then transferred to a mold, stored at -15°C for 12 hours, and then thawed at 25°C and 50% relative humidity for 12 hours.

4. A self-charging motion sensor device, characterized in that include: (1) An integrated supercapacitor prepared as claimed in any one of claims 1 to 3; (2) Sandwich structure: a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) piezoelectric film with through holes is embedded between two layers of PVA / SA hydrogel electrolyte, with a through hole density of ≥ 4 / cm 2 , aperture 1mm 2 . (3) An electrode is in situ grown on the surface of the membrane according to the process for preparing PANI-LT-GO, and a motion sensor with a self-charging effect is obtained after trimming the edges.

5. The device according to claim 4, characterized in that: The specific steps of embedding a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) piezoelectric film with through holes between two layers of PVA / SA hydrogel electrolyte are as follows: spread the PVA / SA-based hydrogel electrolyte solution prepared above in a culture dish, freeze it at -15°C for 3 hours and then take it out, stick the punched PVDF-TrFE film tightly to the colloid surface in the culture dish, cover it with an equal amount of PVA-based aqueous solution, and refrigerate it again at -15°C for 12 hours. After taking it out, place it at 25°C and 50% humidity for 12 hours, and then cut it to obtain a gel electrolyte membrane containing a piezoelectric film.

6. The device according to claim 4, characterized in that: The piezoelectric film through-holes allow ions to migrate through the hydrogel layer, and the device generates a self-charging voltage of 0.3-0.5V when bent and deformed.

7. The device according to claim 4, characterized in that: The device responds to pressure linearly in the range of 0-50 kPa, and the voltage signal is positively correlated with the pressure (R 2 ≥0.98).

8. An electrode material structure, characterized in that: It is composed of polyaniline regulated by low-temperature in-situ polymerization of GO, has a worm-like continuous porous morphology, a thickness of ≥60μm, and seamless contact with the hydrogel electrolyte interface.

9. The electrode material according to claim 8, wherein: The crystallinity of the polyaniline is improved by low-temperature polymerization, and the XRD spectrum shows characteristic peaks at 14° and 18°.

10. A wearable device comprising the apparatus according to any one of claims 4 to 7, for monitoring human motion signals.

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