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CN-121656358-B - Self-driven humidity sensor for respiration monitoring and energy collection

CN121656358BCN 121656358 BCN121656358 BCN 121656358BCN-121656358-B

Abstract

The invention provides a self-driven humidity sensor for respiratory monitoring and energy collection, which is constructed by using a concave structure with patterned copper and aluminum electrodes to remarkably enhance the surface hydrophilicity and ion conductivity of halloysite nanotube HNTs modified by 1-butyl-3-methylimidazole chloride, is favorable for uniform film deposition and efficient interface charge transfer, realizes 510mV output voltage in a wide humidity range, has a response speed which is 4 times that of pure HNTs, realizes voltage amplification by serial connection, and can accurately distinguish various human respiratory modes and detect simulated apnea events by utilizing the high sensitivity and quick dynamic response characteristics of the sensor, and combines a machine learning classifier.

Inventors

  • YANG ZHIMIN
  • WANG JINQIANG
  • Xin Jiale
  • XU CHENGXUAN
  • GUO LULU
  • XU BAOLU

Assignees

  • 山东第二医科大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (9)

  1. 1. A self-driven humidity sensor for respiratory monitoring and energy harvesting, comprising: An insulating substrate having a groove; Copper electrodes and aluminum electrodes arranged on two sides of the groove; The wet sensitive material layer is filled in the groove and covers part of the copper electrode and the aluminum electrode, is a halloysite nanotube composite material modified by ionic liquid, and is an organic-inorganic hybrid composite material formed by embedding 1-butyl-3-methylimidazole chloride between halloysite nanotube layers through electrostatic action; the self-driven humidity sensor performs hydrogen evolution reaction and oxygen reduction reaction at the cathode simultaneously, and the output voltage in an aerobic environment is higher than that in an anaerobic environment.
  2. 2. The self-driven humidity sensor of claim 1 wherein the mass fraction of 1-butyl-3-methylimidazole chloride in the ionic liquid modified halloysite nanotube composite is 5% -15%.
  3. 3. The self-driven humidity sensor of claim 1 wherein the distance between the copper electrode and the aluminum electrode is 800-900 μm.
  4. 4. The self-driven humidity sensor of claim 1 wherein the thickness of the humidity sensitive material layer film forms a uniform film by controlling the concentration and coating amount of the composite solution, the concentration of the ionic liquid modified halloysite nanotube composite solution is 50mg/mL, and the coating amount is 10 μl.
  5. 5. The self-driven humidity sensor of claim 1 wherein the humidity sensitive material layer produces an output voltage of 510mV at 98% relative humidity.
  6. 6. The self-driven humidity sensor of claim 1 wherein the self-driven humidity sensor has a detection range of 11-98% RH, an output voltage of 510mV, and response and recovery times of 4s and 5s, respectively.
  7. 7. The self-driven humidity sensor of claim 1 wherein a plurality of the self-driven humidity sensors are connected in series to achieve amplification of output voltage.
  8. 8. Use of a self-driven humidity sensor according to any one of claims 1 to 7 in a respiratory monitoring device, wherein the self-driven humidity sensor is integrated in a mask or face piece for real-time monitoring of different breathing patterns of a human body, identification of apnoea events and physiological status determination.
  9. 9. Use of a self-driven humidity sensor according to any one of claims 1-7 in a human-computer interaction device, wherein the self-driven humidity sensor implements voice recognition, contactless on-off control and coded communication functions by detecting changes in humidity field.

Description

Self-driven humidity sensor for respiration monitoring and energy collection Technical Field The invention relates to the technical field of humidity sensors, in particular to a self-driven humidity sensor for respiratory monitoring and energy collection. Background Humidity sensors are critical for monitoring environmental moisture and are widely used in industrial, agricultural and everyday life applications. Their role in the healthcare field is particularly remarkable in that by detecting humidity changes in exhaled air, non-invasive, real-time tracking of physiological conditions can be achieved. Respiratory rate and pattern are critical vital signs, and abnormalities can be used as early indicators of sleep apnea, chronic obstructive pulmonary disease, or cardiac arrest. The near saturation of humidity of the exhaled gas provides a convenient and non-invasive source of signals for monitoring respiratory activity. While flexible electronics hold promise for wearable health monitoring, most existing systems still rely on external power sources, which complicates integration, compromises wearability and affects comfort. The self-powered circuit sensor can directly acquire energy from human bodies or environments, and provides a new way for a wearable health monitoring platform. Various self-powered mechanisms have been explored for humidity sensing, including triboelectric, piezoelectric and ion diffusion effects. However, these methods often have limitations such as reliance on mechanical activation, slow response speed, or limited output stability. Recently, electrochemical humidity (ECH) sensors based on cell-like structures have become a promising alternative, which are capable of generating a voltage without an external bias voltage by utilizing a humidity-dependent redox reaction. Despite some advances in the art, widespread use of ECH sensors has been hampered by trade-offs between output performance and response speed, often due to insufficient ionic conductivity or slow water adsorption-desorption kinetics in the sensing layer. To address these challenges, researchers have explored various functional nanomaterials to enhance ECH sensor performance. Among them, halloysite Nanotubes (HNTs) have been attracting attention due to their natural abundance, high specific surface area and abundant hydrophilic groups, showing potential as humidity sensitive materials. Previous studies have shown that HNTs-based composites can significantly improve the humidity detection range and response characteristics of ECH sensors. However, the inherent ion transport and water uptake properties of unmodified HNTs are still insufficient to support the rapid, stable signal acquisition required for real-time respiratory monitoring. Disclosure of Invention The present invention proposes a self-driven humidity sensor for respiratory monitoring and energy harvesting based on Ionic Liquid (IL) functionalized Halloysite Nanotubes (HNTs), wherein HNTs are modified with 1-butyl-3-methylimidazole chloride ([ BMIM ] Cl) to enhance hydrophilicity and ionic conductivity. Unlike conventional planar device structures, the concave structural design with patterned copper and aluminum electrodes creates a unique geometry that enables uniform thin film coating, enhanced interfacial contact, and efficient charge transport. With the benefit of this unique architecture, the resulting sensor exhibits a wide detection range (11-98% RH), a high output voltage of 510mV, and a fast response/recovery time (4 s and 5s, respectively), making it suitable for real-time breathing pattern recognition. In particular, in a first aspect, the present invention proposes a self-driven humidity sensor for respiratory monitoring and energy harvesting, comprising: An insulating substrate having a groove; Copper electrodes and aluminum electrodes arranged on two sides of the groove; and a humidity-sensitive material layer filled in the groove and covering part of the copper electrode and the aluminum electrode, wherein the humidity-sensitive material layer comprises a halloysite nanotube composite material modified by ionic liquid. Further, the ionic liquid is 1-butyl-3-methylimidazole chloride. Further, in the ionic liquid modified halloysite nanotube composite material, the mass fraction of the 1-butyl-3-methylimidazole chloride is 5-15%. Further, the distance between the copper electrode and the aluminum electrode is 800-900 μm. Further, the thickness of the wet-sensitive material layer film was uniform by controlling the concentration of the composite material solution, which was 50mg/mL, and the coating amount, which was 10. Mu.L. Further, the moisture sensitive material layer produces an output voltage of 510mV at 98% relative humidity. Further, the self-driven humidity sensor performs hydrogen evolution reaction and oxygen reduction reaction at the cathode at the same time. Further, a plurality of the self-driven humidity sensors are connected in series