An all-integrated self-powered electrochromic gel strain sensor and application thereof

Abstract

The application discloses a kind of full integration self-powered electrochromic gel strain sensor and its application, including a full solid-state supercapacitor, a current fluctuation signal monitoring device and a strain sensor, the full solid-state supercapacitor is charged by an electrochemical workstation.The application assembles electrochromic gel into full solid-state supercapacitor with conductive glass, and constructs strain sensor combined with conductive metal foil, successfully realizes the multifunctional application of the material.By integrating the two, a self-powered strain sensing system is formed, which can not only visualize the change in real time, but also monitor human movement at any time, with high portability and functionality.

Description

Technical Field

[0001] This invention belongs to the field of electrochromic gel technology, and specifically relates to a fully integrated self-powered electrochromic gel strain sensor and its application. Background Technology

[0002] As a core component of wearable devices, strain sensors, through precise design, can continuously and in real-time monitor physiological parameters such as human dynamics, heart rate, and pulse. However, traditional strain sensors mostly rely on semiconductor and metallic materials. Although these materials have significant performance advantages, their high rigidity and limited biocompatibility severely restrict their widespread application and further development in the field of human health monitoring. Therefore, developing innovative strain sensors with flexibility, portability, and excellent biocompatibility has become a key challenge that urgently needs to be overcome in the current scientific research field.

[0003] Gel materials based on unique polymer network structures not only exhibit excellent mechanical flexibility but also remarkable biocompatibility, making them ideal candidate materials for constructing advanced strain sensors. However, traditional gel materials typically rely on bulky external power sources for power, a limitation that hinders their widespread adoption and, to some extent, restricts the expansion and development of their functions.

[0004] To address the aforementioned issues, Huang et al. conducted related research, fabricating an integrated self-powered system based on a polyvinyl alcohol (PVA) / polyacrylamide-acrylic acid (PAMAA) / glycerol (Gly) / sodium chloride (NaCl) dual-network ionic organic hydrogel. This system consists of a strain sensor and a flexible all-solid-state supercapacitor (J. Huang, S. Peng, J. Gu, G. Chen, J. Gao, J. Zhang, L. Hou, X. Yang, X. Jiang, L. Guan, Self-powered integrated system of astrain sensor and flexible all-solid-state supercapacitor by using a high-performance ionic organohydrogel, Mater. Horiz. 7(8)(2020) 2085-2096.). Although this self-powered system successfully solved the problem of relying on a large external power source, it still has some shortcomings. For example, the system structure is relatively complex, containing many layers, and in practical applications, it cannot effectively monitor the energy state of the external power source in real time.

[0005] To address this issue, developing integrated, miniaturized energy storage systems with energy visualization capabilities has become a key technological path to enhance the self-powered capability of strain sensors and reduce their dependence on external power sources. This technological breakthrough is expected to drive the development of strain sensors towards greater compactness and convenience, providing strong technical support for cutting-edge fields such as intelligent health monitoring and wearable devices. It will also lay a solid scientific foundation for the continuous progress of human health and the widespread application of intelligent technologies. Summary of the Invention

[0006] This invention overcomes the shortcomings of existing technologies and provides a fully integrated self-powered electrochromic gel strain sensor.

[0007] Another object of the present invention is to provide an application of the above-mentioned fully integrated self-powered electrochromic gel strain sensor. The technical solution of the present invention is as follows:

[0008] A fully integrated, self-powered electrochromic gel strain sensor includes an all-solid-state supercapacitor, a current fluctuation signal monitoring device, and a strain sensor. The all-solid-state supercapacitor is charged via an electrochemical workstation.

[0009] The all-solid-state supercapacitor comprises two conductive glasses and an electrochromic gel sandwiched between the two conductive glasses.

[0010] The strain sensor includes two conductive metal foils and an electrochromic gel sandwiched between the two conductive metal foils. A conductive glass is electrically connected to one of the conductive metal foils via a wire, and a current fluctuation signal monitoring device is disposed on the wire.

[0011] Another conductive metal foil is electrically connected to another conductive glass via another wire.

[0012] This electrochromic gel is prepared by mixing and reacting acrylamide monomer, carboxymethyl cellulose solution, N,N'-methylenebisacrylamide, lithium chloride, azobisisobutyronitrile, viologen derivative and ferrocene.

[0013] The structural formula of this viologen derivative is:

[0014] In a preferred embodiment of the present invention, the preparation method of the electrochromic gel includes: mixing acrylamide monomer with 2wt% carboxymethyl cellulose solution at a mass ratio of 1:1.5, then adding N,N'-methylenebisacrylamide, lithium chloride, azobisisobutyronitrile, viologen derivative and ferrocene, stirring thoroughly and evenly, pouring into a mold, and reacting at 80-100℃ for 1.5-2 hours to obtain the gel.

[0015] More preferably, the solvent of the 2wt% carboxymethyl cellulose solution is a mixture of DMSO and H2O in a volume ratio of 3:2.

[0016] More preferably, the mass ratio of N,N'-methylenebisacrylamide, lithium chloride and azobisisobutyronitrile is 0.01-0.015:0.5-1.2:0.01.

[0017] In a further preferred embodiment, the mass ratio of the viologen derivative to ferrocene is 8.8:1.

[0018] In a preferred embodiment of the present invention, the conductive glass is made of ITO or FTO.

[0019] In a preferred embodiment of the present invention, the conductive metal foil is made of copper or zinc.

[0020] In a preferred embodiment of the present invention, the current fluctuation signal monitoring device includes an ammeter and a multimeter.

[0021] The above-mentioned fully integrated self-powered electrochromic gel strain sensor is used in the preparation of a human motion state monitoring device.

[0022] A human motion state monitoring device, which has the above-mentioned fully integrated self-powered electrochromic gel strain sensor.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention exhibits superior color-changing performance. When a step voltage (-0.8V to 2.2V) is applied for cyclic testing and the in-situ transmittance spectrum change is recorded, the transmittance change of the electrochromic gel in the initial state can reach 53.1%. After 3500 seconds of continuous operation, the transmittance stabilizes at 42.6%, and the optical transmittance remains at 80%, fully demonstrating the stability and high efficiency of this material during long-term operation.

[0025] 2. The electrochromic gel prepared in this invention, combined with conductive glass, constitutes an all-solid-state supercapacitor. After 1900 cycles, this all-solid-state supercapacitor retains 76.7% of its original surface capacitance, and its coulombic efficiency remains consistently above 91%, demonstrating excellent cycle stability. Furthermore, this all-solid-state supercapacitor also possesses the ability to continuously power a light bulb, proving its superior performance in energy storage and release.

[0026] 3. This invention assembles electrochromic gel with conductive glass to form an all-solid-state supercapacitor, and combines it with conductive metal foil to construct a strain sensor, successfully realizing the multifunctional application of this material. By integrating the two, a self-powered strain sensing system is formed. This system can not only visualize changes in electrical charge in real time, but also monitor human movement at any time, combining high portability and functionality. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the fully integrated self-powered electrochromic gel strain sensor in Embodiment 1 of the present invention.

[0028] Figure 2 The spectral cycling stability of the electrochromic gel in Example 1 of this invention at 571 nm.

[0029] Figure 3 The constant current charge-discharge cycle performance of the all-solid-state supercapacitor in Embodiment 1 of the present invention is shown in the voltage window of -0.8-2.2V.

[0030] Figure 4 A digital photograph of an LED light illuminated by an all-solid-state supercapacitor connected in series in Embodiment 1 of the present invention.

[0031] Figure 5 This shows the experimental results of the fully integrated self-powered electrochromic gel strain sensor in Embodiment 1 of the present invention under 12 cycles of stretching and relaxation at 50% strain.

[0032] Figure 6 The time-current response curve of the fully integrated self-powered electrochromic gel strain sensor in Embodiment 1 of the present invention is shown after 60 cycles at 20% strain.

[0033] Figure 7 This invention displays digital images and corresponding time-current response curves of the fully integrated self-powered electrochromic gel strain sensor in human neck motion monitoring, as shown in Embodiment 1 of the present invention.

[0034] Figure 8 This displays digital images and corresponding time-current response curves of the fully integrated self-powered electrochromic gel strain sensor in Embodiment 1 of the present invention during human finger movement monitoring.

[0035] Figure 9 This invention displays digital images and corresponding time-current response curves of the fully integrated self-powered electrochromic gel strain sensor in human arm motion monitoring, as shown in Embodiment 1 of the present invention.

[0036] Figure 10 This invention displays digital images and corresponding time-current response curves of the fully integrated self-powered electrochromic gel strain sensor in Embodiment 1 of the present invention during human walking and running motion monitoring. Detailed Implementation

[0037] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0038] Example 1

[0039] (1) Preparation of electrochromic gel: 1g of acrylamide monomer was mixed with 1.5g of 2wt% carboxymethyl cellulose solution (the solvent was prepared by mixing DMSO and H2O in a volume ratio of 3:2), and 0.015g of N,N'-methylenebisacrylamide, 1g of lithium chloride, 0.01g of azobisisobutyronitrile, 0.1158g of viologen derivative (dissolved in 1.2mL of a mixed solvent prepared by mixing DMSO and H2O in a volume ratio of 1:5) and 0.0132g of ferrocene (dissolved in 0.3mL of DMSO) were added. After thorough mixing, the mixed solution was poured into a mold. The system was reacted at 90℃ for 2h to obtain the target product.

[0040] The structural formula of the above viologen derivative is as follows:

[0041] (2) Construction of all-solid-state supercapacitor: By placing two pieces of ITO conductive glass on the upper and lower surfaces of the electrochromic gel, an all-solid-state supercapacitor structure can be constructed.

[0042] (3) Construction of strain sensor: Two copper foils are placed on the upper and lower surfaces of the electrochromic gel to form a strain sensor.

[0043] (4) Construction of a fully integrated self-powered electrochromic gel strain sensor: The aforementioned all-solid-state supercapacitor was charged using an electrochemical workstation. After charging, it was connected to the strain sensor via wires to provide a stable power supply to the sensor, and an ammeter was connected in series in the circuit. This system can capture current fluctuations caused by strain in real time, thereby accurately monitoring the dynamic response of strain.

[0044] like Figure 1 As shown, the fully integrated self-powered electrochromic gel strain sensor fabricated in this embodiment consists of two parts: one is an all-solid-state supercapacitor assembled from the electrochromic gel and two ITO conductive glasses, which is connected to an electrochemical workstation for charging; the other is that after the supercapacitor is fully charged, it serves as a power source connected to the electrochromic gel strain sensor, providing it with continuous power. Furthermore, by connecting an ammeter in series, the change in current during motion is monitored in real time, thereby enabling the detection and analysis of the motion state.

[0045] An all-solid-state supercapacitor was coupled to an electrochemical workstation, and a step voltage from -0.8V to 2.2V was applied using a two-electrode testing method. During this process, a UV-Vis spectrophotometer was simultaneously connected to monitor and record the dynamic response curve of transmittance as a function of voltage at a wavelength of λ = 571 nm in real time. Figure 2As shown, the all-solid-state supercapacitor prepared in this embodiment exhibits a transmittance change of up to 53.1% in its initial state. After 3500 seconds of continuous operation, the transmittance stabilizes at 42.6%, and the optical transmittance remains above 80%, fully demonstrating its excellent stability and high efficiency in electrochromic performance during long-term operation.

[0046] The all-solid-state supercapacitor was coupled with an electrochemical workstation, and charge-discharge tests were conducted using a two-electrode method within a voltage window of -0.8V to 2.2V to evaluate its electrochemical performance. Figure 3 As shown, the all-solid-state supercapacitor in this embodiment retains 79% of its initial surface capacitance after 1900 charge-discharge cycles, and its coulombic efficiency remains stable at over 92.9%, fully demonstrating its excellent charge-discharge cycle stability and superior long-term performance.

[0047] like Figure 4 As shown, the two all-solid-state supercapacitors in this embodiment, when connected in series, can effectively provide power to light-emitting diodes (LEDs), verifying their feasibility and performance in practical applications.

[0048] After the all-solid-state supercapacitor is charged through an electrochemical workstation, it is connected to a strain sensor by wires and an ammeter is connected in series to monitor the change in current response of the strain sensor during deformation. Figure 5 This embodiment demonstrates a fully integrated, self-powered electrochromic gel strain sensor subjected to 12 cycles of stretching and relaxation at 50% strain. Figure 5 As shown, the fully integrated self-powered electrochromic gel strain sensor exhibits similar decay trends in both current and potential electronic signals due to energy consumption caused by the self-discharge process. When mechanical strain is applied, the electrochromic gel-based strain sensor is stretched, resulting in a significant decrease in current (inversely related to the change in resistance). Furthermore, in the held state after strain relief, the sensor current remains stable. This self-powered strain sensor demonstrates excellent sensitivity and long-term stability.

[0049] Figure 6 This is the time-current response curve of the fully integrated self-powered electrochromic gel strain sensor of this embodiment after 60 cycles at 20% strain. Figure 6 As shown, the fully integrated, self-powered electrochromic gel strain sensor exhibits a periodic and stable change in current signal during cyclic stretching and releasing at a constant strain of 50%. Clearly, the current decreases. However, the relative current change (ΔI / I0; ΔI is the relative current as a function of strain, and I0 is the initial current before strain) remains almost constant during 60 cycles of loading.

[0050] Figures 7 to 10The images shown are, in sequence, digital images and corresponding time-current response curves of the fully integrated self-powered electrochromic gel strain sensor in this embodiment during human neck, finger, arm, walking, and running motion monitoring. Figures 7 to 10 As shown, the fully integrated, self-powered electrochromic gel strain sensor exhibits varying current responses under different movement states, including neck, finger, arm, walking, and running. This demonstrates that the electrochromic gel strain sensor can be effectively driven by an all-solid-state supercapacitor and possesses the capability to comprehensively monitor diverse human movements.

[0051] Example 2

[0052] The difference from Example 1 is that 0.01g of N,N-methylenebisacrylamide and 0.5g of lithium chloride were added.

[0053] Example 3

[0054] The difference from Example 1 is that the reaction was carried out at 100°C for 1.5 hours.

[0055] Example 4

[0056] The difference from Example 1 is that by placing two pieces of FTO conductive glass on the upper and lower surfaces of the electrochromic gel, an all-solid-state supercapacitor structure can be constructed.

[0057] Example 5

[0058] The difference from Example 1 is that by placing two zinc foils on the upper and lower surfaces of the electrochromic gel, a strain sensor can be formed.

[0059] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A fully integrated self-powered electrochromic gel strain sensor, characterized by: The application relates to a full-integrated self-powered electrochromic gel strain sensor, which comprises a full-solid-state super capacitor, a current fluctuation signal monitoring device and a strain sensor, wherein the full-solid-state super capacitor is charged by an electrochemical workstation, the full-solid-state super capacitor comprises two conductive glasses and an electrochromic gel sandwiched between the two conductive glasses, the strain sensor comprises two conductive metal foils and an electrochromic gel sandwiched between the two conductive metal foils, one conductive glass is electrically connected to one conductive metal foil through a wire, the current fluctuation signal monitoring device is arranged on the wire, the other conductive metal foil is electrically connected to the other conductive glass through another wire, the electrochromic gel is prepared by mixing and reacting acrylamide monomers, a 2wt% carboxymethyl cellulose solution, N,N'-methylene bisacrylamide, lithium chloride, azobisisobutyronitrile, a viologen derivative and ferrocene, and the preparation method of the electrochromic gel comprises the following steps: mixing acrylamide monomers and 2wt% carboxymethyl cellulose solution according to a mass ratio of 1:1.5, then adding N,N'-methylene bisacrylamide, lithium chloride, azobisisobutyronitrile, a viologen derivative and ferrocene, uniformly stirring, pouring into a mold, and reacting at 80-100 DEG C for 1.5-2 h. The solvent of the 2wt% carboxymethyl cellulose solution is prepared by mixing DMS and H2O according to a volume ratio of 3:

2. The mass ratio of the N,N'-methylene bisacrylamide, lithium chloride and azobisisobutyronitrile is 0.01-0.015:0.5-1.2:0.

01. The mass ratio of the viologen derivative and ferrocene is 8.8:

1. The material of the conductive glass is ITO or FTO. The material of the conductive metal foil is copper or zinc. The structure of the viologen derivative is 2. A fully integrated self-powered electrochromic gel strain sensor according to claim 1, wherein: The current fluctuation signal monitoring device comprises an ammeter and a multimeter.

3. A fully integrated self-powered electrochromic gel strain sensor according to claim 2, wherein:

9. The use of the full-integrated self-powered electrochromic gel strain sensor in any one of claims 1 to 8 in the preparation of a human motion state monitoring device.

4. A fully integrated self-powered electrochromic gel strain sensor according to claim 3, wherein: The human motion state monitoring device comprises the full-integrated self-powered electrochromic gel strain sensor in any one of claims 1 to 8.

5. A fully integrated self-powered electrochromic gel strain sensor according to claim 4, wherein: ​ 6. A fully integrated self-powered electrochromic gel strain sensor according to any one of claims 1 to 5, wherein: ​ 7. A fully integrated self-powered electrochromic gel strain sensor according to any one of claims 1 to 5, wherein: ​ 8. A fully integrated self-powered electrochromic gel strain sensor according to any one of claims 1 to 5, wherein: ​ ​ 10. A human motion state monitoring apparatus characterized by comprising: ​

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