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CN-122016952-A - Hydrogen sensor for lithium battery safety monitoring and preparation method of sensitive material

CN122016952ACN 122016952 ACN122016952 ACN 122016952ACN-122016952-A

Abstract

The invention relates to the technical field of gas sensors, in particular to a hydrogen sensor for lithium battery safety monitoring and a preparation method of a sensitive material, which are used for solving the problems of slower recovery speed and insufficient sensitivity of the existing hydrogen sensitive material; compared with common materials such as tin oxide, zinc oxide and the like, the tungsten trioxide is used as a matrix of a sensitive material, the response characteristic of the tungsten trioxide is more sensitive to hydrogen, the intrinsic sensitivity and the reaction rate of the material to hydrogen are improved through the synergistic dual sensitization effect of K + bulk phase doping and palladium nanoparticle surface catalysis, a sacrificial template is introduced into a tungsten trioxide sensitive layer prepared by aerosol deposition, a sectional annealing process is adopted, a controllable porous structure is constructed while the template is fully removed and the film continuity is ensured, the sensitivity and the response/recovery performance of a hydrogen sensor are improved, and the sensor is suitable for a lithium ion battery thermal runaway safety monitoring scene with extremely severe early warning requirements.

Inventors

  • WANG CONG
  • WEI JIE

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260512
Application Date
20260227

Claims (10)

  1. 1. The preparation method of the sensitive material for lithium battery safety monitoring is characterized by comprising the following steps of: Step a1, mixing sodium tungstate, potassium sulfate and deionized water, magnetically stirring, regulating pH with hydrochloric acid solution, heating for reaction, centrifugally separating, discarding supernatant, washing precipitate, drying, adding absolute ethyl alcohol, ultrasonically dispersing, adding polyvinylpyrrolidone and potassium chloride, mixing and stirring, centrifugally separating, discarding supernatant, washing precipitate, drying, and calcining to obtain an intermediate product; Step a2, ultrasonically dispersing an intermediate product and an ethanol solution, placing the intermediate product and the ethanol solution in an ice-water bath for stirring, adding a palladium acetate solution, stirring, adding a sodium borohydride solution, stirring, centrifugally separating, discarding supernatant, respectively washing precipitate with absolute ethanol and distilled water, drying, grinding and sieving to obtain modified tungsten trioxide; Washing styrene with sodium hydroxide solution and distilled water respectively, adding anhydrous magnesium sulfate for drying, distilling under reduced pressure, adding ethanol solution and dispersing agent, mixing and stirring, placing in an oil bath, adding an initiator, stirring for reaction, cooling, centrifuging, discarding supernatant, adding anhydrous ethanol, performing ultrasonic dispersion, filtering, drying and sieving to obtain monodisperse polystyrene microspheres, and performing dry mixing and sieving on modified tungsten trioxide and monodisperse polystyrene microspheres to obtain a sensitive material.
  2. 2. The preparation method of the sensitive material for lithium battery safety monitoring according to claim 1, wherein the dosage ratio of sodium tungstate, potassium sulfate, deionized water, absolute ethyl alcohol, polyvinylpyrrolidone and potassium chloride in the step a1 is 1.5-2g:0.4-0.6g:40-80mL:40-80mL:0.5-0.8g:0.1-0.2g, the concentration of the hydrochloric acid solution is 3mol/L, and the type of polyvinylpyrrolidone is PVP-K30.
  3. 3. The preparation method of the sensitive material for lithium battery safety monitoring according to claim 1 is characterized in that the dosage ratio of the intermediate product, the ethanol solution, the palladium acetate solution and the sodium borohydride solution in the step a2 is 100-150mg:30-50mL:0.2-0.5mL:1-2mL, the mass fraction of the ethanol solution is 20%, the concentration of the palladium acetate solution is 5g/L, and the concentration of the sodium borohydride solution is 10g/L.
  4. 4. The preparation method of the sensitive material for lithium electric safety monitoring according to claim 1 is characterized in that the dosage ratio of styrene, anhydrous magnesium sulfate, ethanol solution, dispersing agent, initiator, absolute ethanol and modified tungsten trioxide in the step a3 is 3-15mL:3-5g:80-100mL:2-3g:0.1-0.2g:50-60mL:10-15g, the mass fraction of sodium hydroxide solution is 5%, the mass fraction of ethanol solution is 80%, the dispersing agent is polyvinylpyrrolidone PVP-K30, and the initiator is azobisisobutyronitrile.
  5. 5. The preparation method of the hydrogen sensor for the thermal runaway early warning of the lithium ion battery is characterized by comprising the following steps of: Washing a substrate with acetone, absolute ethyl alcohol and deionized water, drying, activating, mounting an electrode on the surface, adding a sensitive material into an aerosol generator, spraying the sensitive material onto the surface of the substrate at a high speed to obtain a composite film, carrying out sectional heat treatment on the composite film, cooling to obtain a sensitive layer, carrying out sputter deposition on the sensitive layer, activating, and mounting a micro heater on the back of the substrate to obtain the hydrogen sensor.
  6. 6. The method for preparing the hydrogen sensor for the thermal runaway warning of the lithium ion battery, which is disclosed in claim 5, is characterized by comprising a substrate, an electrode arranged on the surface of the substrate, a sensitive layer covered on the electrode and a micro heater arranged on the back of the substrate, wherein the sensitive layer also comprises a sensitization layer, and the micro heater provides an operating temperature of 50-350 ℃.
  7. 7. The method for preparing the hydrogen sensor for the thermal runaway warning of the lithium ion battery according to claim 5, wherein the sensitive layer is prepared by the method for preparing the sensitive material in the first aspect, the substrate is one of alumina ceramic, aluminum nitride ceramic, glass or silicon-based insulating substrate, the electrode is an interdigital electrode structure or a counter electrode structure, the material is one of Pt, au, ag or alloys thereof, and the sensitive layer is a nano layer/nano particle layer formed by one or more of Pd, pt and Au.
  8. 8. The method for preparing the hydrogen sensor for the thermal runaway warning of the lithium ion battery according to claim 5, wherein the thickness of the sensitive layer is 0.5-30 μm, the pore size distribution is 0.5-10 μm, and the thickness of the sensitization layer is 0.5-20nm.
  9. 9. The method for preparing a hydrogen sensor for thermal runaway warning of a lithium ion battery according to claim 5, wherein the staged heat treatment comprises the following temperature program: heating to 120 ℃, wherein the heating rate is 1-3 ℃ per minute, and preserving heat for 30-60 minutes; heating to 280 ℃, heating up to 0.5-2 ℃ per min, and preserving heat for 30-90min; heating to 360 ℃, wherein the heating rate is 0.5-1 ℃ per minute, and preserving heat for 30-90min; Heating to 450 ℃, wherein the heating rate is 1 ℃ per minute, and preserving heat for 60-120 minutes; heating to 475 ℃ with the heating rate of 0.5-1 ℃ per minute, and preserving heat for 30-60min.
  10. 10. The method for preparing a hydrogen sensor for thermal runaway warning of a lithium ion battery according to claim 9, wherein when the thickness of the sensitive layer is more than 10 μm or the volume fraction of polystyrene in the sensitive material is more than or equal to 40vol%, the heat preservation time of a 280 ℃ platform and a 360 ℃ platform is prolonged to 90-120min, or the temperature rising rate of 360-450 ℃ is reduced to 0.5 ℃ so as to reduce the risk of carbon residue caused by limited diffusion of thermal decomposition products and reduce the cracking/peeling probability.

Description

Hydrogen sensor for lithium battery safety monitoring and preparation method of sensitive material Technical Field The invention relates to the technical field of gas sensors, in particular to a hydrogen sensor for lithium battery safety monitoring and a preparation method of a sensitive material. Background With the wide application of lithium ion batteries in electric vehicles, energy storage systems and consumer electronics, the problem of operation safety is continuously focused, and researches show that in the early stage of overcharge, short circuit or thermal runaway of the lithium ion batteries, a series of side reactions can occur between electrode materials and electrolyte, and the generation and release of combustible gases such as hydrogen are accompanied, and compared with temperature or voltage changes, the generation of hydrogen is earlier and the indication is stronger, so that the safety state of the lithium ion batteries is reflected by detecting the change of the concentration of hydrogen in the environment, and the lithium ion batteries are considered to be a monitoring means with obvious advantages. In the existing hydrogen sensing materials, the characteristics of stable structure, low cost, mature process and the like of the metal oxide semiconductor materials are widely studied, wherein tungsten trioxide has response characteristics more sensitive to hydrogen compared with common materials such as tin oxide, zinc oxide and the like, besides resistance change caused by a surface adsorption-reaction mechanism of the traditional metal oxide, obvious gasochromic phenomena can also occur under the action of hydrogen, so that the hydrogen response process of the tungsten trioxide not only involves surface reaction, but also is accompanied with the processes of bulk injection, valence change and the like of hydrogen, and the mechanism of synergistic action of the surface reaction and bulk reaction ensures that the tungsten trioxide has higher sensitivity and good application potential to hydrogen. Therefore, the hydrogen sensor for lithium battery safety monitoring and the preparation method of the sensitive material have important significance in the technical field of gas sensors. Disclosure of Invention In order to overcome the technical problems, the invention aims to provide a hydrogen sensor for lithium battery safety monitoring and a preparation method of a sensitive material, which solve the problems of low recovery speed and insufficient sensitivity of the existing hydrogen sensitive material. The aim of the invention can be achieved by the following technical scheme: in a first aspect, the application provides a preparation method of a sensitive material for lithium battery safety monitoring, comprising the following steps: Adding sodium tungstate, potassium sulfate and deionized water into a three-neck flask provided with a stirrer and a thermometer, magnetically stirring at a rotating speed of 300r/min for 30min, regulating the pH value to 2-3 by using a hydrochloric acid solution, transferring into a hydrothermal reaction kettle, heating to 180 ℃ at a heating rate of 2-5 ℃ for reacting for 12h, centrifugally separating, discarding supernatant, washing precipitate by using distilled water for 2-3 times, drying in a vacuum drying box at 60 ℃ for 4-6h, adding absolute ethyl alcohol, ultrasonically dispersing for 30min, adding polyvinylpyrrolidone and potassium chloride, mixing and stirring at a rotating speed of 400-600r/min for 12-24h, centrifugally separating, discarding supernatant, washing precipitate by using distilled water for 2-3 times, drying in a vacuum drying box at 60 ℃ for 4-6h, transferring into a muffle furnace, and calcining at 400 ℃ for 2-3h to obtain an intermediate product; Step a2, adding the intermediate product and the ethanol solution into a three-neck flask provided with a stirrer and a thermometer, performing ultrasonic dispersion for 30min, placing the three-neck flask into an ice-water bath at 0-5 ℃, stirring for 30min at the rotating speed of 400-600r/min, adding a palladium acetate solution, continuously stirring for 10-15min, adding a sodium borohydride solution, continuously stirring for 10-15min, performing centrifugal separation, discarding supernatant, washing precipitate with absolute ethanol and distilled water for 2-3 times respectively, drying in a vacuum drying oven at 60 ℃ for 4-6h, transferring the precipitate into a mortar, grinding, and sieving by a screen to obtain modified tungsten trioxide with the particle size of 0.5-2 mu m; Step a3, washing styrene with sodium hydroxide solution and distilled water for 2-3 times respectively, adding anhydrous magnesium sulfate for drying for 12-24 hours, distilling under reduced pressure under the protection of nitrogen, adding into a three-mouth flask with a stirrer and a thermometer, adding ethanol solution and a dispersing agent, mixing and stirring for 30 minutes, placing into an oil bath with t