A novel pressure sensor based on solid-state electrolyte and a preparation method thereof

Abstract

The application discloses a novel pressure sensor based on a solid electrolyte and a preparation method thereof. The pressure sensor comprises a sensing element, wherein the sensing element comprises a solid electrolyte, a working electrode, a counter electrode, a current collector and a flexible polymer film, and the current collector, the working electrode, the solid electrolyte, the counter electrode and the current collector are sequentially arranged from top to bottom; and the flexible polymer film is used for packaging. The pressure sensor senses the change of external pressure by the deformation of the working electrode under the action of pressure, the migration of ions at the contact interface with the solid electrolyte and the change of electric potential. The application has the advantages of simple design, easy integration with an electronic system, convenient integration into various electronic devices, good chemical stability, application in various working environments, corrosion resistance, high sensitivity, rapid response and low energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of pressure sensor technology, specifically relating to a novel pressure sensor based on a solid electrolyte and its fabrication method. Background Technology

[0002] With the rapid development of smart industry, pressure sensors, serving as windows for information exchange, are becoming increasingly important. Existing sensors mainly include piezoresistive, capacitive, and piezoelectric sensors. However, as application scenarios expand, the performance requirements for sensors are becoming increasingly stringent. For example, sensors need higher sensitivity, wider pressure detection range, and lower detection frequencies. However, none of the aforementioned sensors possess low-frequency signal (<5Hz) detection capabilities. The fundamental reason is that these sensors typically rely on electronic transmission for signal acquisition, and the high-speed transmission of electrons makes it difficult for them to effectively capture low-frequency signals. To address this challenge, a novel ion-based pressure sensor has emerged. This type of sensor uses ions as the information transmission medium, fully utilizing the slower transport speed of ions compared to electrons, enabling it to match low-frequency pressure signals on a time scale. This matching mechanism allows the new pressure sensor to effectively detect low-frequency pressure signals, meeting the needs for low-frequency signal detection in specific application scenarios. This type of sensor has broad application prospects in fields requiring long-term, low-frequency pressure monitoring, such as smart manufacturing, medical monitoring, and environmental detection.

[0003] However, the electrolyte systems used in existing pressure sensors based on this principle are mostly liquid, which has disadvantages such as difficulty in encapsulation, easy volatilization and leakage leading to decreased sensor performance and insufficient sensitivity. These disadvantages not only affect the performance of the sensor, but may also cause pollution to the surrounding environment. Furthermore, the application of such sensors in specific environments such as high temperature, high pressure, and strong magnetic field is limited, which increases the manufacturing difficulty and cost of the sensor.

[0004] Therefore, developing a pressure sensor with high safety, good stability, and stable chemical properties is a technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments.

[0006] Solid electrolytes mainly include oxides, sulfides, solid polymers (excluding gel polymers), and composite materials composed of the above. Sensors based on solid electrolytes benefit from the good processability of solid electrolytes, allowing them to adapt to different packaging requirements, helping to maintain the integrity of the packaging structure and reducing the risk of leakage. Simultaneously, solid electrolytes exhibit high chemical stability, effectively resisting the corrosive effects of chemicals in the external environment, further reducing the risk of leakage and thus meeting the needs of sensors and other devices operating in complex environments.

[0007] This invention provides a novel pressure sensor based on a solid electrolyte and its fabrication method. Based on the operating characteristics of existing pressure sensors, the structure of the pressure sensor is designed specifically for this purpose. The pressure sensor provided by this invention deforms under the applied pressure, causing ion migration at the interface with the solid electrolyte and generating a potential change. This change in potential allows the sensor to sense the external pressure change, thereby converting external pressure energy into electrical energy. Furthermore, there is a correlation between the external pressure and the generated real-time voltage. By measuring the real-time voltage, this correlation is then used to convert the real-time voltage into the corresponding pressure.

[0008] To achieve the above objectives, according to one aspect of the present invention, a pressure sensor based on a solid electrolyte using a carbon nanotube thin film is provided. The pressure sensor includes a sensing element for converting the pressure energy of the pressure to be measured into electrical energy. The sensing element includes a solid electrolyte, a working electrode, a counter electrode, a current collector, and a flexible polymer thin film. The components are arranged from top to bottom as the current collector, working electrode, solid electrolyte, counter electrode, and current collector. The flexible polymer thin film is used for encapsulation.

[0009] The pressure sensor detects changes in external pressure by sensing the deformation of the working electrode under pressure, which causes ions to migrate at the interface with the solid electrolyte, resulting in a change in potential.

[0010] Furthermore, the flexibility of the solid electrolyte should be greater than 1.0 × 10⁻⁶. -12 Pa -1 .

[0011] Furthermore, the working electrode material includes, but is not limited to, carbon nanotubes, graphene, and activated carbon.

[0012] Furthermore, the solid electrolyte includes, but is not limited to, sulfide solid electrolytes, oxide solid electrolytes, solid polymer electrolytes (excluding gel polymers), and composite materials composed of the above materials.

[0013] Furthermore, the flexible polymer film material includes, but is not limited to, polyoxymethylene acrylate film, polydimethylsiloxane film, and polystyrene film.

[0014] Furthermore, in the novel pressure sensor based on solid-state electrolyte, the current collector includes, but is not limited to, copper foil, aluminum foil, nickel, and stainless steel.

[0015] Furthermore, in the novel pressure sensor based on solid electrolyte, the working electrode and the counter electrode are completely covered by the solid electrolyte.

[0016] According to another aspect of the present invention, a method for fabricating a novel pressure sensor based on a solid electrolyte is provided, characterized in that the manufacturing method includes the following steps: first, fixing the working electrode and the counter electrode on two current collectors respectively; then, placing the solid electrolyte between the working electrode and the counter electrode; and finally encapsulating the above-mentioned element with a flexible polymer film.

[0017] Furthermore, the novel pressure sensor based on solid-state electrolyte is capable of forming a pressure sensor array to sense distributed pressure.

[0018] In summary, compared with the prior art, the novel pressure sensor based on solid-state electrolyte provided by this invention has the following advantages:

[0019] 1. The pressure sensor is based on the deformation of the working electrode under pressure, which causes ion migration at the interface between the working electrode and the solid electrolyte, resulting in a potential change. This allows the sensor to sense changes in external pressure. Furthermore, the pressure sensor can obtain the current pressure based on the relationship between the current corresponding to the electrical energy converted from pressure and the corresponding pressure. This enables real-time monitoring of the pressure to be measured. The pressure sensor does not require an external power supply during operation, reducing power consumption. It also features a large operating range, high sensitivity, and fast response speed, making it suitable for various environments and exhibiting good environmental adaptability.

[0020] 2. The pressure sensor based on solid electrolyte solves the problem of performance degradation caused by easy volatilization and leakage of pressure sensors based on liquid electrolyte, and reduces the potential pollution to the surrounding environment.

[0021] 3. The pressure sensor based on solid electrolyte solves the problem of difficult packaging of pressure sensors based on liquid electrolyte, reduces the manufacturing difficulty and cost of the sensor, has a simple structure, and has great potential for industrial production and application.

[0022] 4. The pressure sensor based on solid electrolyte has good manufacturability, which enables it to adapt to different scenario requirements.

[0023] 5. The pressure sensor based on solid electrolyte can operate in a low-temperature environment of -40℃. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein:

[0025] Figure 1 This is a schematic diagram of the sensing element of the pressure sensor of the present invention;

[0026] Figure 2 The sensor's response to pressure at room temperature and -40°C;

[0027] Figure 3 The sensor's response to 10 Pa pressure in an environment of -40℃;

[0028] Figure 4 The response of the sensor to 1 kPa pressure at -20℃ is shown in Comparative Example 1.

[0029] Figure 5 The response of the sensor to 1 kPa pressure at -20°C is shown in Comparative Example 2.

[0030] Figure 1 In the middle: 1-flexible polymer film, 2-working electrode, 3-counter electrode, 4-solid electrolyte, 5-signal output line, 61-current collector, 62-current collector. Detailed Implementation

[0031] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0032] Example 1:

[0033] See Figure 1 and Figure 2 This invention provides a novel pressure sensor based on a solid-state electrolyte and its manufacturing method. The pressure sensor includes a sensing element comprising a solid-state electrolyte, a working electrode, a counter electrode, a current collector, and a flexible polymer film, arranged from top to bottom as the current collector, working electrode, solid-state electrolyte, counter electrode, and current collector; the flexible polymer film is used for encapsulation; the solid-state electrolyte has a flexibility of 2.8 × 10⁻⁶. -12 Pa -1 .

[0034] Pressure sensors are based on the deformation of the working electrode under pressure, which causes ions to migrate at the interface with the solid electrolyte, resulting in a change in potential, thereby sensing changes in external pressure.

[0035] In this embodiment, the solid electrolyte is lithium lanthanum zirconium oxide (LLZO, Li7La3Zr2O). 12Solid electrolyte; flexible polymer film is polyoxymethylene acrylate film; electrodes are made of carbon nanotube film.

[0036] Experiments have shown that the solid electrolyte in this invention is also applicable to other lithium lanthanum zirconium oxide solid electrolytes, the key point being that the flexibility of the solid electrolyte should be greater than 1.0 × 10⁻⁶. -12 Pa -1 .

[0037] This invention also provides a novel pressure sensor based on a solid-state electrolyte and its fabrication method, such as... Figure 1 , Figure 2 The preparation method includes the following steps:

[0038] (1) First, fix the working electrode and the counter electrode on the two current collectors respectively.

[0039] (2) Then place the solid electrolyte between the working electrode and the counter electrode.

[0040] (3) The structure is encapsulated with a flexible polymer film, and the structure is arranged from top to bottom as current collector, working electrode, solid electrolyte, counter electrode, and current collector.

[0041] To characterize the performance of the pressure sensor, the following performance tests were performed on the pressure sensor:

[0042] Please see Figure 2 The sensor's response to pressures ranging from 83 kPa to 496 kPa was measured at room temperature and -40°C. At room temperature, as the pressure increased from 83 kPa to 496 kPa, the sensor's output signal increased from 0.34 mA / cm². 2 It increased to 1.46 mA / cm 2 At a low temperature of -40℃, as the pressure increased from 83 kPa to 496 kPa, the sensor's output signal decreased from 0.28 mA / cm². 2 Increased to 1.05 mA / cm 2 .

[0043] Please see Figure 3 The sensor's response to a 10 Pa pressure in an environment of -40°C. When a 10 Pa pressure is applied to the sensor, the open-circuit voltage of the sensor increases by 0.2 mV.

[0044] Example 2:

[0045] In this embodiment, the solid electrolyte is lithium titanium phosphate (LATP) solid electrolyte; the flexible polymer film is a polydimethylsiloxane film; and the flexibility of the solid electrolyte is greater than 1.0 × 10⁻⁶. -12 Pa -1The electrode is made of carbon nanotube array, and the sensor is prepared using the same method as in Example 1.

[0046] Example 3:

[0047] In this embodiment, the solid electrolyte is a lithium-phosphorus-sulfur-chlorine (LiPSCl) solid electrolyte; the flexible polymer film is a polystyrene film; and the flexibility of the solid electrolyte is greater than 1.0 × 10⁻⁶. -12 Pa -1 The electrode is made of graphene film, and the sensor is prepared using the same method as in Example 1.

[0048] Comparative Example 1:

[0049] In this embodiment, the electrolyte is a gel electrolyte, specifically a polyvinyl alcohol-hydroxymethyl cellulose gel electrolyte; the flexible polymer film is a polyoxymethylene acrylate film; the electrode is made of a carbon nanotube film, and the sensor fabrication method is the same as in Example 1.

[0050] Please see Figure 4 The pressure sensor based on polyvinyl alcohol-hydroxymethyl cellulose gel electrolyte operates at a temperature of -20℃, has a lower limit of pressure detection of 1kPa, and a signal variation value of -30nA to 60nA, with unstable output.

[0051] Pressure sensors prepared using gel electrolytes have insufficient sensitivity and unstable signals.

[0052] Comparative Example 2:

[0053] In this embodiment, the electrolyte is Li7La3Zr2Nb. 0.1 O 12 Solid electrolyte, with a flexibility of 7.4 × 10⁻⁶. -13 Pa -1 The flexible polymer film is a polyoxymethylene acrylate film; the electrode is made of carbon nanotube film, and the sensor preparation method is the same as in Example 1.

[0054] Please see Figure 5 Based on Li7La3Zr2Nb 0.1 O 12 The solid-state electrolyte pressure sensor operates at a temperature of -20℃, with a pressure detection limit of 1 kPa. The signal strength gradually decreases, with a maximum change of 3 nA and a minimum change of 0.9 nA, exhibiting unstable output. This indicates that the flexibility of the solid-state electrolyte needs to be controlled within a reasonable range; otherwise, it may cause problems such as insufficient pressure sensor sensitivity.

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A novel pressure sensor based on a solid-state electrolyte, characterized in that: The pressure sensor includes a sensing element that converts the pressure energy of the pressure to be measured into electrical energy. The sensing element includes a solid electrolyte, a working electrode, a counter electrode, and a current collector. The structure is arranged as follows: current collector, working electrode, solid electrolyte, counter electrode, current collector; The solid electrolyte has a flexibility greater than 1.0 × 10⁻⁶. −12 Pa -1 The solid electrolyte does not include gel electrolyte; the pressure sensor is based on the deformation of the working electrode under pressure, which causes the migration of ions at the interface with the solid electrolyte, resulting in a change in potential, thereby sensing the change in external pressure.

2. The novel pressure sensor based on solid-state electrolyte according to claim 1, characterized in that: It also includes a flexible polymer film for encapsulating the pressure sensor.

3. The novel pressure sensor based on a solid-state electrolyte according to claim 1 or 2, characterized in that: The working electrode is made of one or more of the following materials: carbon nanotubes, graphene, and activated carbon.

4. The novel pressure sensor based on a solid-state electrolyte according to claim 1 or 2, characterized in that: The solid electrolyte includes one or more of the following: sulfide solid electrolyte, oxide solid electrolyte, and solid polymer electrolyte.

5. The novel pressure sensor based on solid-state electrolyte according to claim 2, characterized in that: The flexible polymer film is made of one or more of the following materials: polyoxymethylene acrylate film, polydimethylsiloxane film, and polystyrene film.

6. The novel pressure sensor based on a solid-state electrolyte according to claim 1 or 2, characterized in that: The current collector includes one or more of the following: copper foil, aluminum foil, nickel, stainless steel, and platinum sheet.

7. The novel pressure sensor based on a solid-state electrolyte according to claim 1 or 2, characterized in that: It also includes signal output lines that are connected to the current collector on the working electrode side and the current collector on the counter electrode side, respectively.

8. The novel pressure sensor based on a solid-state electrolyte according to claim 1 or 2, characterized in that: The working electrode and the counter electrode are completely covered by the solid electrolyte.

9. The method for fabricating a novel pressure sensor based on a solid-state electrolyte according to claim 2, characterized in that: First, the working electrode and the counter electrode are fixed on two current collectors respectively. Then, the solid electrolyte is placed between the working electrode and the counter electrode to obtain a pressure sensor. Finally, it is encapsulated with a flexible polymer film.

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