Sensor for detecting gas based on two-dimensional material

Abstract

The invention discloses a sensor for detecting gas based on a two-dimensional material, and relates to the technical field of semiconductor sensors and battery safety. In order to solve the problems that an existing lithium ion battery management system lags in early warning and a traditional sensor is difficult to integrate and not resistant to corrosion, flexible polyimide is used as a substrate of the sensor, a back gate type two-dimensional material field effect transistor serves as a core, and a gate dielectric layer is arranged between a gate and a two-dimensional material channel in a spaced mode. A functional modification layer is arranged on the surface of the channel to improve the gas recognition specificity, a breathable hydrophobic layer covers one side deviating from the gate dielectric layer, and the breathable hydrophobic layer is matched with a passivation layer and a sensing window to form anti-corrosion packaging. The sensor can be implanted into a battery, real-time in-situ detection of ppb-level trace characteristic gas is realized through an adsorption-charge transfer-field effect amplification mechanism, and the sensor is linked with a BMS (Battery Management System) to realize ultra-early warning of thermal runaway. The device has the advantages of flexibility, easiness in integration, high sensitivity, corrosion resistance and long service life, and the safety management level of the battery is greatly improved.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor sensors and battery safety technology, and in particular to a gas detection sensor based on two-dimensional materials and its manufacturing method. Background Technology

[0002] Lithium-ion batteries, due to their high energy density, long cycle life, and high charge / discharge efficiency, have been widely used in various fields such as new energy vehicles, energy storage devices, and portable electronic terminals. However, in actual use, lithium-ion batteries are highly susceptible to internal thermal runaway reactions if subjected to abuse conditions such as overcharging, over-discharging, internal short circuits, high-temperature environments, or mechanical impacts. This reaction causes a rapid increase in battery temperature and pressure, which can lead to electrolyte decomposition, casing rupture, and even serious safety accidents such as combustion and explosion, posing a significant threat to personal and property safety.

[0003] To ensure the safe use of lithium-ion batteries, existing technologies commonly employ Battery Management Systems (BMS) to monitor and control the battery's operating status. Current mainstream BMSs primarily determine whether the battery is in an abnormal operating state by collecting macroscopic electrical and thermal parameters such as voltage, current, and surface temperature. However, research shows that thermal runaway in lithium-ion batteries is a multi-stage, progressive reaction process, essentially a result of violent chemical reactions occurring in components such as the electrolyte and electrode materials within the battery. Before thermal runaway enters the irreversible, violent reaction stage, its very early nascent stage is accompanied by the generation of characteristic gases—the electrolyte inside the battery decomposes first, releasing decomposition products including volatile organic compounds (VOCs) such as dimethyl carbonate (DMC) and ethylene carbonate (EC), as well as characteristic gases such as carbon monoxide (CO), carbon dioxide (CO2), and hydrogen (H2). The appearance of these characteristic gases occurs much earlier than significant anomalies in macroscopic parameters such as voltage, current, and surface temperature, and they are core sensitive signals reflecting early internal battery faults.

[0004] Current battery management systems (BMS) rely on macroscopic parameter monitoring, which can only detect abnormal signals when the thermal runaway reaction has progressed to a later stage. By this time, the thermal runaway process is often irreversible, leaving the BMS with very little time to activate safety protection measures, making it difficult to fundamentally prevent safety accidents. Therefore, real-time, in-situ monitoring of characteristic gases in the early stages of thermal runaway inside the battery can significantly advance the safety warning window, providing sufficient time for subsequent safety intervention. This is a key technological path to address the safety hazards of thermal runaway in lithium-ion batteries. However, existing gas sensor technologies are insufficient to meet the specific application requirements inside lithium-ion batteries, mainly due to the following core defects: insufficient size and integration, limited sensitivity and detection lower limit, poor corrosion resistance and stability, and power consumption and compatibility issues.

[0005] It is evident that developing a novel sensor that can be implanted inside a battery, can operate stably for a long time, and has a high sensitivity for detecting characteristic gases has become a pressing technical challenge in this field. Summary of the Invention

[0006] This invention aims to solve the technical problem of detecting trace characteristic gases in confined spaces, and provides a flexible gas sensor and its manufacturing method that can be implanted inside confined devices such as lithium-ion battery cells to detect characteristic gases (especially VOCs) generated by adverse reactions inside the device in real time with high sensitivity and high specificity, so as to realize ultra-early safety warning. At the same time, it also provides a lithium-ion battery safety monitoring system that includes the sensor.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A gas detection sensor based on two-dimensional materials, whose core structure is a back-gate field-effect transistor (FET) array, specifically includes the following key components: Flexible substrate, using a polymer film resistant to electrolyte corrosion; A gate is disposed on the surface of the flexible substrate; The gate dielectric layer is a high-k dielectric material layer that covers the gate surface and is separated between the gate and the subsequent two-dimensional material channel. A two-dimensional material channel is disposed on the side of the gate dielectric layer away from the gate, forming the conductive channel of the field-effect transistor; The source and drain are respectively disposed at both ends of the two-dimensional material channel, forming an ohmic contact with the two-dimensional material channel; A functionalized modification layer is disposed on the side of the two-dimensional material channel opposite to the gate dielectric layer to enhance the recognition specificity and detection sensitivity for specific gases. A breathable and hydrophobic layer covers the functionalized modification layer, allowing gas molecules to pass through while preventing liquid electrolyte from penetrating; The packaging structure includes a passivation layer covering the source, drain, gate leads and non-sensing areas of the flexible substrate, wherein the passivation layer has a sensing window in the area corresponding to the breathable and hydrophobic layer; The electrical lead structure has source, drain and gate leads fabricated on a flexible substrate and completely protected by a passivation layer; the ends of the leads extend to the outside of the battery and achieve reliable electrical connection with the battery management system (BMS) through structures such as sealed electrode posts that cooperate with the battery cover or aluminum-plastic film.

[0008] Preferably, the flexible substrate is a polyimide film with a thickness of 10-50 μm.

[0009] Preferably, the material of the two-dimensional material channel is selected from one or more of graphene, transition metal chalcogenides, MXene, and black phosphorus, and the length of the two-dimensional material channel is 0.5-100 μm and the width is 1-100 μm.

[0010] Preferably, the transition metal chalcogenide is at least one of MoS2, WS2, and WSe2; and the MXene is at least one of Ti3C2 and Tx.

[0011] Preferably, the gate dielectric layer is made of aluminum oxide or hafnium oxide prepared by atomic layer deposition, with a thickness of 5-20 nm.

[0012] Preferably, the electrode materials of the source, drain, and gate are selected from gold (Au), platinum (Pt), or titanium / gold (Ti / Au) stacks.

[0013] Preferably, the functionalized modification layer is an atomic doping layer, a heterojunction, or a noble metal nanoparticle-supported layer.

[0014] Preferably, the material of the breathable and hydrophobic layer is Parylene-C or a fluoropolymer; the passivation layer is alumina (Al2O3) or silicon nitride (Si3N4) prepared by atomic layer deposition (ALD) or plasma enhanced chemical vapor deposition (PECVD), with a thickness of 30-100 nanometers; and the sensing window is a micropore array or nanochannel structure.

[0015] Preferably, the sensor is an array structure, and the two-dimensional material channels of different field-effect transistors in the array are made of different materials or different functionalized modification layers.

[0016] This sensor achieves gas detection based on the core mechanism of "adsorption-charge transfer-field effect amplification", and the specific process is as follows: (1) Gas adsorption and charge transfer: Characteristic gas molecules generated inside the battery diffuse through the sensing window and the gas-permeable hydrophobic layer to the functionalized modification layer on the surface of the two-dimensional material channel. Under the action of the functionalized modification layer, the target gas molecules form specific adsorption with the two-dimensional material, and charge transfer occurs at the same time (the gas molecules act as electron donors or acceptors), resulting in a change in the concentration of charge carriers (electrons or holes) in the two-dimensional material channel.

[0017] (2) Field-effect signal amplification: The two-dimensional material channel, gate, gate dielectric layer, source, and drain constitute a back-gate FET. The high k characteristic of the gate dielectric layer enables the gate voltage to efficiently control the initial carrier concentration and Fermi level position of the channel. The change in carrier concentration caused by gas adsorption is equivalent to applying an additional gate voltage, which causes a significant shift in the FET's transfer characteristic curve (the relationship between source / drain current Id and gate voltage Vg), achieving high-rate electrical amplification of minute charge changes.

[0018] (3) Signal output and recognition: The gas concentration is converted into a measurable electrical signal through two modes. One is the threshold voltage drift (ΔVth) mode: the Id-Vg curve is shifted as a whole, and ΔVth is correlated with the gas concentration; the other is the current modulation (ΔId / Id0) mode: under a fixed gate voltage, the source drain current Id changes relative to each other.

[0019] By leveraging the differences in signal response of different functionalized FETs in the sensor array, combined with the signal processing algorithm of the BMS, it is possible to achieve specific identification and concentration quantification of various characteristic gases.

[0020] Another object of the present invention is to provide a method for manufacturing the aforementioned two-dimensional material-based sensor for gas detection, comprising the following steps: Step S1, Substrate preparation: Spin-coat a polyimide (PI) precursor solution onto a clean silicon wafer or glass, and cure it by programmed temperature rise to form a flexible PI substrate with a thickness of 10-50 micrometers. Step S2, Gate fabrication: Gate metal is deposited and patterned on the surface of a flexible PI substrate using photolithography and electron beam evaporation processes to form the gate; Step S3, gate dielectric layer preparation: A 5-20 nm thick high-k dielectric material layer is uniformly grown on the exposed surface of the gate and flexible PI substrate using atomic layer deposition (ALD) technology to serve as the gate dielectric layer; Step S4, Two-dimensional material channel preparation: A two-dimensional material thin film is grown on the surface of the gate dielectric layer by chemical vapor deposition (CVD), or a pre-made two-dimensional material film is transferred to a designated area of ​​the gate dielectric layer by dry / wet transfer, and then the two-dimensional material is patterned by photolithography and plasma etching to form a two-dimensional material channel. Step S5, Functionalization: A functionalized modification layer is formed on the side of the two-dimensional material channel away from the gate dielectric layer by atomic doping, heterostructure construction or noble metal nanoparticle loading process. Step S6, Source and Drain Electrode Fabrication: Metal electrodes are deposited and patterned at both ends of the two-dimensional material channel through photolithography, electron beam evaporation and lift-off processes to form the source and drain electrodes; Step S7, Preparation of breathable and hydrophobic layer: Deposit Parylene-C or fluoropolymer film on the functionalized modification layer to form a breathable and hydrophobic layer; Step S8, Passivation layer preparation: An inorganic passivation layer 30-100 nm thick is deposited on the entire device surface by atomic layer deposition (ALD) or plasma enhanced chemical vapor deposition (PECVD), covering the source, drain, gate leads and non-sensing areas of the flexible PI substrate. Step S9, Sensing Window Fabrication: Micropore arrays or nanochannels are formed in the region of the passivation layer corresponding to the breathable hydrophobic layer by photolithography and reactive ion etching (RIE) processes, serving as sensing windows; Step S10, Device Stripping and Lead Connection: The fabricated sensor device is mechanically stripped from the silicon substrate, and the leads of the gate, source, and drain are connected to external connection circuits or lead terminals.

[0021] Another objective of this invention is to provide a lithium-ion battery safety monitoring system, which consists of the aforementioned gas detection sensor based on two-dimensional materials and a BMS. The specific integration method and workflow are as follows: (1) Sensor implantation: The flexible sensor is attached to the outer surface of the hard-shell battery core, the inner wall of the soft-pack battery, or directly laminated on the separator layer between the positive and negative electrodes, and the lead wire extends to the outside of the battery through the sealed electrode post.

[0022] (2) Signal acquisition and calibration: The BMS acquires electrical signals such as Id and Vth from the sensor in real time, and periodically corrects the sensor baseline drift through the built-in calibration algorithm. Based on the pre-stored "electrical signal-gas concentration" calibration curve, the signal is converted into the concentration value of the corresponding characteristic gas.

[0023] (3) Anomaly detection and alarm: The BMS has a built-in multi-level threshold alarm module and a dynamic fusion algorithm module. Multi-level thresholds: Alarm thresholds are set for different gases such as VOCs (first-level threshold > 50 ppb) and CO (second-level threshold > 10 ppm), triggering "early warning" and "high-risk alarm" respectively; Dynamic fusion algorithm: A machine learning algorithm based on time series analysis, which analyzes the rate of change of gas concentration and the correlation of multiple gas signals, distinguishes between interfering factors and real precursors of thermal runaway, and reduces the false alarm rate.

[0024] (4) Active intervention: When an early fault signal is confirmed, the BMS automatically executes safety policies, including limiting the charging and discharging current, starting the active cooling system, and sending early warning information to the user or cloud platform.

[0025] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) Early warning capability: Directly monitor the characteristic gases generated during the initiation of battery thermal runaway. Compared with traditional temperature and pressure monitoring, the warning time is several minutes to tens of minutes earlier, realizing the leap from "response-based" to "predictive" safety management.

[0026] (2) High sensitivity and high specificity: The high specific surface area of ​​the two-dimensional material combined with the functionalized modification layer enables the sensor to reach the ppb level detection limit and can specifically identify a variety of target gases, resulting in high early warning accuracy.

[0027] (3) In-situ real-time monitoring: The sensor is implanted inside the battery, directly contacting the source of the fault, eliminating external environmental interference, and truly reflecting the internal state of the battery, with strong monitoring timeliness.

[0028] (4) Flexible and easy to integrate: Based on a flexible PI substrate, the device is thin, flexible and adaptable to the complex space inside the cell, with minimal impact on the battery energy density and internal structure, and compatible with existing battery manufacturing processes.

[0029] (5) High stability and long lifespan: The gate dielectric layer, passivation layer and breathable hydrophobic layer form a multi-protection structure, which effectively resists electrolyte corrosion and ensures that the sensor works reliably during the battery life.

[0030] (6) System-level safety enhancement: Intelligent linkage with BMS enables closed-loop management of "detection-judgment-alarm-intervention", which fundamentally improves the intrinsic safety level of lithium-ion batteries and has significant social and economic value. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the gas detection sensor based on two-dimensional materials according to the present invention; Figure 2 This is a schematic diagram of the flexible array and packaging of a gas detection sensor based on two-dimensional materials according to the present invention. Detailed Implementation

[0032] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0033] Example 1 A gas detection sensor based on two-dimensional materials, whose core structure is a back-gate field-effect transistor (FET) array, specifically includes the following key components: Flexible substrate, using a polymer film resistant to electrolyte corrosion; A gate is disposed on the surface of the flexible substrate; The gate dielectric layer is a high-k dielectric material layer that covers the gate surface and is separated between the gate and the subsequent two-dimensional material channel. A two-dimensional material channel is disposed on the side of the gate dielectric layer away from the gate, forming the conductive channel of the field-effect transistor; The source and drain are respectively disposed at both ends of the two-dimensional material channel, forming an ohmic contact with the two-dimensional material channel; A functionalized modification layer is disposed on the side of the two-dimensional material channel opposite to the gate dielectric layer to enhance the recognition specificity and detection sensitivity for specific gases. A breathable and hydrophobic layer covers the functionalized modification layer, allowing gas molecules to pass through while preventing liquid electrolyte from penetrating; The packaging structure includes a passivation layer covering the source, drain, gate leads and non-sensing areas of the flexible substrate, wherein the passivation layer has a sensing window in the area corresponding to the breathable and hydrophobic layer; The electrical lead structure has source, drain and gate leads fabricated on a flexible substrate and completely protected by a passivation layer; the ends of the leads extend to the outside of the battery and achieve reliable electrical connection with the battery management system (BMS) through structures such as sealed electrode posts that cooperate with the battery cover or aluminum-plastic film.

[0034] The flexible substrate is a polyimide film with a thickness of 10 μm; the two-dimensional material channel is made of graphene, with a length of 1 μm and a width of 5 μm; the gate dielectric layer is made of aluminum oxide prepared by atomic layer deposition with a thickness of 5 nm; the source, drain, and gate electrode materials are gold (Au); and the functionalized modification layer is an atomically doped layer.

[0035] The breathable and hydrophobic layer is made of Parylene-C; the passivation layer is aluminum oxide (Al2O3) prepared by atomic layer deposition (ALD) with a thickness of 30 nanometers; the sensing window is a micropore array or nanochannel structure.

[0036] The sensor is an array structure, and the two-dimensional material channels of different field-effect transistors in the array are made of different materials or different functionalized modification layers.

[0037] This sensor achieves gas detection based on the core mechanism of "adsorption-charge transfer-field effect amplification", and the specific process is as follows: (1) Gas adsorption and charge transfer: Characteristic gas molecules generated inside the battery diffuse through the sensing window and the gas-permeable hydrophobic layer to the functionalized modification layer on the surface of the two-dimensional material channel. Under the action of the functionalized modification layer, the target gas molecules form specific adsorption with the two-dimensional material, and charge transfer occurs at the same time (the gas molecules act as electron donors or acceptors), resulting in a change in the concentration of charge carriers (electrons or holes) in the two-dimensional material channel.

[0038] (2) Field-effect signal amplification: The two-dimensional material channel, gate, gate dielectric layer, source, and drain constitute a back-gate FET. The high k characteristic of the gate dielectric layer enables the gate voltage to efficiently control the initial carrier concentration and Fermi level position of the channel. The change in carrier concentration caused by gas adsorption is equivalent to applying an additional gate voltage, which causes a significant shift in the FET's transfer characteristic curve (the relationship between source / drain current Id and gate voltage Vg), achieving high-rate electrical amplification of minute charge changes.

[0039] (3) Signal output and recognition: The gas concentration is converted into a measurable electrical signal through two modes. One is the threshold voltage drift (ΔVth) mode: the Id-Vg curve is shifted as a whole, and ΔVth is correlated with the gas concentration; the other is the current modulation (ΔId / Id0) mode: under a fixed gate voltage, the source drain current Id changes relative to each other.

[0040] By leveraging the differences in signal response of different functionalized FETs in the sensor array, combined with the signal processing algorithm of the BMS, it is possible to achieve specific identification and concentration quantification of various characteristic gases.

[0041] A method for manufacturing a gas detection sensor based on two-dimensional materials includes the following steps: Step S1, Substrate preparation: Spin-coat a polyimide (PI) precursor solution onto a clean silicon wafer, and cure it by programmed temperature rise to form a 10-micron-thick flexible PI substrate. Step S2, Gate fabrication: Gate metal is deposited and patterned on the surface of a flexible PI substrate using photolithography and electron beam evaporation processes to form the gate; Step S3, Gate dielectric layer fabrication: A 5-nanometer-thick high-k dielectric material layer is uniformly grown on the exposed surface of the gate and flexible PI substrate using atomic layer deposition (ALD) technology to serve as the gate dielectric layer; Step S4, Two-dimensional material channel preparation: A two-dimensional material thin film is grown on the surface of the gate dielectric layer by chemical vapor deposition (CVD), or a pre-made two-dimensional material film is transferred to a designated area of ​​the gate dielectric layer by dry / wet transfer, and then the two-dimensional material is patterned by photolithography and plasma etching to form a two-dimensional material channel. Step S5, Functionalization: A functionalized modification layer is formed on the side of the two-dimensional material channel away from the gate dielectric layer by atomic doping, heterostructure construction or noble metal nanoparticle loading process. Step S6, Source and Drain Electrode Fabrication: Metal electrodes are deposited and patterned at both ends of the two-dimensional material channel through photolithography, electron beam evaporation and lift-off processes to form the source and drain electrodes; Step S7, Preparation of breathable and hydrophobic layer: Deposit Parylene-C or fluoropolymer film on the functionalized modification layer to form a breathable and hydrophobic layer; Step S8, Passivation layer preparation: A 30 nm thick inorganic passivation layer is deposited on the entire device surface by atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD), covering the source, drain, gate leads and non-sensing areas of the flexible PI substrate. Step S9, Sensing Window Fabrication: Micropore arrays or nanochannels are formed in the region of the passivation layer corresponding to the breathable hydrophobic layer by photolithography and reactive ion etching (RIE) processes, serving as sensing windows; Step S10, Device Stripping and Lead Connection: The fabricated sensor device is mechanically stripped from the silicon substrate, and the leads of the gate, source, and drain are connected to external connection circuits or lead terminals.

[0042] A lithium-ion battery safety monitoring system, comprising a gas detection sensor based on two-dimensional materials and a BMS, wherein the specific integration method and workflow are as follows: (1) Sensor implantation: The flexible sensor is attached to the outer surface of the hard-shell battery core, the inner wall of the soft-pack battery, or directly laminated on the separator layer between the positive and negative electrodes, and the lead wire extends to the outside of the battery through the sealed electrode post.

[0043] (2) Signal acquisition and calibration: The BMS acquires electrical signals such as Id and Vth from the sensor in real time, and periodically corrects the sensor baseline drift through the built-in calibration algorithm. Based on the pre-stored "electrical signal-gas concentration" calibration curve, the signal is converted into the concentration value of the corresponding characteristic gas.

[0044] (3) Anomaly detection and alarm: The BMS has a built-in multi-level threshold alarm module and a dynamic fusion algorithm module. Multi-level thresholds: Alarm thresholds are set for different gases such as VOCs (first-level threshold > 50 ppb) and CO (second-level threshold > 10 ppm), triggering "early warning" and "high-risk alarm" respectively; Dynamic fusion algorithm: A machine learning algorithm based on time series analysis, which analyzes the rate of change of gas concentration and the correlation of multiple gas signals, distinguishes between interfering factors and real precursors of thermal runaway, and reduces the false alarm rate.

[0045] (4) Active intervention: When an early fault signal is confirmed, the BMS automatically executes safety policies, including limiting the charging and discharging current, starting the active cooling system, and sending early warning information to the user or cloud platform.

[0046] Example 2 This example provides a gas detection sensor based on two-dimensional materials, which is basically the same as that in Example 1, except that the thickness of the flexible substrate is 20 μm; the material of the two-dimensional material channel is a transition metal chalcogenide, the length of the two-dimensional material channel is 3 μm and the width is 20 μm; the transition metal chalcogenide is MoS2; the material of the gate dielectric layer is hafnium oxide prepared by atomic layer deposition, with a thickness of 10 nm; the electrode materials of the source, drain and gate are platinum (Pt); the functionalized modification layer is a heterojunction; the material of the gas-permeable hydrophobic layer is a fluoropolymer; and the passivation layer is silicon nitride (Si3N4) prepared by plasma-enhanced chemical vapor deposition (PECVD), with a thickness of 50 nm.

[0047] Example 3 This example provides a gas detection sensor based on two-dimensional materials, which is basically the same as that in Example 1, except that the thickness of the flexible substrate is 30 μm; the material of the two-dimensional material channel is MXene, the length of the two-dimensional material channel is 5 μm, and the width is 25 μm; the MXene is Ti3C2; the material of the gate dielectric layer is aluminum oxide prepared by atomic layer deposition, with a thickness of 13 nm; the electrode materials of the source, drain, and gate are titanium / gold (Ti / Au) stacks; the functionalized modification layer is a noble metal nanoparticle loading layer; the material of the gas-permeable and hydrophobic layer is Parylene-C; and the passivation layer is silicon nitride (Si3N4) prepared by atomic layer deposition (ALD), with a thickness of 60 nm.

[0048] Example 4 This example provides a gas detection sensor based on two-dimensional materials, which is basically the same as that in Example 1, except that the thickness of the flexible substrate is 40 μm; the material of the two-dimensional material channel is graphene, and the length of the two-dimensional material channel is 9 μm and the width is 40 μm; the material of the gate dielectric layer is hafnium oxide prepared by atomic layer deposition, and the thickness is 18 nm; the electrode materials of the source, drain and gate are gold (Au); the functionalized modification layer is an atomic doping layer; the material of the gas-permeable hydrophobic layer is a fluoropolymer; and the passivation layer is silicon nitride (Si3N4) prepared by plasma-enhanced chemical vapor deposition (PECVD), and the thickness is 90 nm.

[0049] Example 5 This example provides a gas detection sensor based on two-dimensional materials, which is basically the same as that in Example 1, except that the thickness of the flexible substrate is 50 μm; the material of the two-dimensional material channel is black phosphorus, and the length of the two-dimensional material channel is 10 μm and the width is 50 μm; the material of the gate dielectric layer is alumina prepared by atomic layer deposition, and the thickness is 20 nm; the electrode materials of the source, drain and gate are platinum (Pt); the functionalized modification layer is an atomic doping layer; the material of the gas-permeable hydrophobic layer is Parylene-C; and the passivation layer is alumina (Al2O3) prepared by atomic layer deposition (ALD), and the thickness is 100 nm.

[0050] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A gas detection sensor based on two-dimensional materials, characterized in that, Its core structure is a back-gate field-effect transistor array, which specifically includes the following key components: Flexible substrate, using a polymer film resistant to electrolyte corrosion; A gate is disposed on the surface of the flexible substrate; The gate dielectric layer is a high-k dielectric material layer that covers the gate surface and is separated between the gate and the subsequent two-dimensional material channel. A two-dimensional material channel is disposed on the side of the gate dielectric layer away from the gate, forming the conductive channel of the field-effect transistor; The source and drain are respectively disposed at both ends of the two-dimensional material channel, forming an ohmic contact with the two-dimensional material channel; A functionalized modification layer is disposed on the side of the two-dimensional material channel away from the gate dielectric layer to enhance the recognition specificity and detection sensitivity for specific gases; A breathable and hydrophobic layer covers the functionalized modification layer, allowing gas molecules to pass through while preventing liquid electrolyte from penetrating; The packaging structure includes a passivation layer covering the source, drain, gate leads and non-sensing areas of the flexible substrate, wherein the passivation layer has a sensing window in the area corresponding to the breathable and hydrophobic layer; The electrical lead structure has source, drain and gate leads fabricated on a flexible substrate and completely protected by a passivation layer; the ends of the leads extend to the outside of the battery and achieve reliable electrical connection with the battery management system through structures such as sealed electrode posts that cooperate with the battery cover or aluminum-plastic film.

2. The gas detection sensor based on two-dimensional materials according to claim 1, characterized in that, The flexible substrate is a polyimide film with a thickness of 10-50 micrometers.

3. The gas detection sensor based on two-dimensional materials according to claim 1, characterized in that, The material of the two-dimensional material channel is selected from one or more of graphene, transition metal chalcogenides, MXene Ti3C2, MXene Tx, and black phosphorus. The length of the two-dimensional material channel is 0.5-100 μm and the width is 1-100 μm.

4. The gas detection sensor based on two-dimensional materials according to claim 1, characterized in that, The gate dielectric layer is made of aluminum oxide or hafnium oxide prepared by atomic layer deposition, with a thickness of 5-20 nanometers.

5. The gas detection sensor based on two-dimensional materials according to claim 1, characterized in that, The source, drain, and gate electrode materials are selected from gold, platinum, or titanium / gold stacks; the functionalized modification layer is an atomic doping layer, a heterojunction, or a noble metal nanoparticle supported layer.

6. The gas detection sensor based on two-dimensional materials according to claim 1, characterized in that, The breathable and hydrophobic layer is made of Parylene-C or a fluoropolymer; the passivation layer is made of alumina or silicon nitride prepared by atomic layer deposition or plasma-enhanced chemical vapor deposition, with a thickness of 30-100 nanometers; the sensing window is a micropore array or a nanochannel structure.

7. The gas detection sensor based on two-dimensional materials according to any one of claims 1-6, characterized in that, The sensor is an array structure containing multiple field-effect transistors, wherein at least two of the field-effect transistors have different materials and / or functionalized modification layers for their two-dimensional material channels.

8. A method for manufacturing a gas detection sensor based on two-dimensional materials as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1, Substrate preparation: Spin-coat a polyimide precursor solution onto a clean silicon wafer or glass, and cure it by programmed temperature rise to form a flexible PI substrate with a thickness of 10-50 micrometers. Step S2, Gate fabrication: Gate metal is deposited and patterned on the surface of a flexible PI substrate using photolithography and electron beam evaporation processes to form the gate; Step S3, gate dielectric layer preparation: A 5-20 nm thick high-k dielectric material layer is uniformly grown on the exposed surfaces of the gate and flexible PI substrate using atomic layer deposition technology to serve as the gate dielectric layer; Step S4, Two-dimensional material channel fabrication: A two-dimensional material thin film is grown on the surface of the gate dielectric layer by chemical vapor deposition, or a pre-fabricated two-dimensional material sheet is transferred to a designated area of ​​the gate dielectric layer by dry / wet transfer, and then the two-dimensional material is patterned by photolithography and plasma etching to form a two-dimensional material channel; Step S5, Functionalization: A functionalized modification layer is formed on the side of the two-dimensional material channel away from the gate dielectric layer by atomic doping, heterostructure construction or noble metal nanoparticle loading process. Step S6, Source and Drain Electrode Fabrication: Metal electrodes are deposited and patterned at both ends of the two-dimensional material channel through photolithography, electron beam evaporation and lift-off processes to form the source and drain electrodes; Step S7, Preparation of breathable and hydrophobic layer: Deposit Parylene-C or fluoropolymer film on the functionalized modification layer to form a breathable and hydrophobic layer; Step S8, Passivation layer preparation: Deposit an inorganic passivation layer 30-100 nm thick on the entire device surface by atomic layer deposition or plasma-enhanced chemical vapor deposition, covering the source, drain, gate leads and non-sensing areas of the flexible PI substrate. Step S9, Sensing Window Fabrication: Micropore arrays or nanochannels are formed in the region of the passivation layer corresponding to the breathable and hydrophobic layer by photolithography and reactive ion etching processes, serving as sensing windows; Step S10, Device Stripping and Lead Connection: The fabricated sensor device is mechanically stripped from the silicon substrate, and the leads of the gate, source, and drain are connected to external connection circuits or lead terminals.

9. A lithium-ion battery safety monitoring system, characterized in that, The invention includes a gas detection sensor and a battery management system (BMS) based on two-dimensional materials as described in any one of claims 1-6; the sensor is embedded inside a lithium-ion battery cell, and its leads extend to the outside of the battery through a sealed structure and are connected to the BMS; the BMS incorporates a calibration algorithm, a multi-level threshold alarm module, a dynamic and fusion algorithm module, and an active intervention module, for real-time acquisition of sensor signals, conversion into gas concentration, identification of abnormal gas generation, and execution of safety strategies.

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