A co-located electrochemical-surface plasmon resonance microfluidic interface detection chip, system and method

Abstract

The present application belongs to the field of interface in-situ detection, electrochemical detection and microfluidic optical sensing technology, and discloses a co-located electrochemical-surface plasmon resonance microfluidic chip, system and method. The microfluidic chip comprises a transparent optical substrate, a metal functional layer, a counter electrode, a reference electrode and a microfluidic structure. The projection of the detection light spot of the metal functional layer on the metal functional layer is located in the electrochemically active region of the working electrode. The microfluidic structure forms a reaction cavity covering the region and the counter electrode and the reference electrode. The system synchronously collects the electrochemical response and the surface plasmon response of the same interface in a controlled liquid environment, and can detect or compare the interface responses under different conditions by changing the electrochemical excitation, the composition of the liquid to be measured, the reaction time or the fluid conditions. The present application eliminates the spatial correspondence error of electrochemical and optical signals from the hardware level, has the advantages of high sensitivity, low sample consumption, continuous testing, wide application range and the like.

Description

Technical Field

[0001] This invention relates to the fields of in-situ interface detection, electrochemical detection, and microfluidic optical sensing technology, specifically to a microfluidic interface detection chip, system, and method that co-integrates an electrochemical working electrode with a surface plasmon resonance sensitive layer. Background Technology

[0002] The interface between a solid surface and a liquid medium changes with potential, current, reactant concentration, temperature, and fluid state. Adsorption, desorption, redox reactions, deposition, dissolution, corrosion, passivation, and structural modification at the interface are widely present in fields such as electrochemical energy storage, corrosion protection, electroplating, electrocatalysis, biosensing, and surface functionalization. Therefore, continuously obtaining interface changes under liquid-phase conditions is a crucial problem that interface detection technology needs to solve. Existing interface detection methods mainly include offline morphology or composition detection, electrochemical detection, and in-situ optical detection. Methods such as scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy can obtain information on interface morphology, thickness, or composition, but usually require stopping the reaction and disassembling, cleaning, drying, or transferring the sample. The results obtained are mostly discrete-time interface states, and sample processing may alter the original interface.

[0003] While electrochemical methods such as cyclic voltammetry, chronoamperometry, and impedance spectroscopy can modulate interfacial potentials and record current, charge transfer, and mass transfer information, the resulting signals are typically a combined response of multiple processes within the effective region of the working electrode, making it difficult to individually reflect continuous changes in refractive index and effective optical thickness near the interface. Surface plasmon resonance detection is sensitive to changes in the refractive index and effective optical thickness of the medium near the metal surface and can continuously detect liquid-phase interfaces without removing the sample. However, optical detection alone cannot actively modulate the interfacial potential, and it is difficult to establish a definite correspondence between optical changes and specific electrochemical operations.

[0004] Combining electrochemical detection with surface plasmon resonance (SPR) detection can provide complementary information. However, in some existing coupled devices, the optical sensing region and the electrochemical reaction region are not completely aligned, and the two types of signals may originate from different local locations. Furthermore, the reaction vessel may suffer from problems such as large size, difficulty in stabilizing the fluid environment, inconvenience in switching between different analytes, and changes in the detection position after repeated assembly. Consequently, existing devices struggle to continuously compare different reaction conditions at the same interface location, and it is also difficult to create a compact interface detection platform with low sample consumption. In other words, the aforementioned existing technologies cannot avoid the problems of concentration gradients, mass transfer delays, and time phase differences between current and optical signals caused by spatial separation or inaccurate correspondence between the electrochemical working electrode reaction region and the SPR optical sensing region. Summary of the Invention

[0005] Based on this, in order to address the shortcomings of existing technologies, a co-located electrochemical-surface plasmon resonance microfluidic interface detection chip, system and method are proposed, which enables the electrochemical reaction region and the surface plasmon sensing region to be located at the same interface, and can simultaneously obtain electrochemical signals and optical signals in a controlled microfluidic environment.

[0006] To achieve the above design objectives, the technical solution of the present invention is as follows: A cosmooth electrochemical-surface plasmon resonance microfluidic interface detection chip, characterized in that it comprises: Transparent optical substrate; A metallic functional layer is disposed on the transparent optical substrate. A portion of the metallic functional layer serves as an electrochemical working electrode in contact with the liquid to be tested, and this portion also serves as a surface plasmon resonance (SPR) sensing layer. Another portion of the metallic functional layer is an electrical connection lead-out area for electrically connecting the electrochemical working electrode to an external circuit. Specifically, the projection of the detection spot onto the metallic functional layer lies within the electrochemically active region of the electrochemical working electrode, thus forming an overlap between the electrochemical region and the SPR optical sensing region. Furthermore, the area of ​​the detection spot does not exceed the area of ​​the electrochemically active region where the electrochemical working electrode contacts the liquid to be tested. Except for the region serving as the electrochemical working electrode, the remaining portion of the metallic functional layer is covered by an insulating layer to avoid direct contact with the liquid to be tested. The electrical connection lead-out area is located outside the reaction chamber covered by the microfluidic structure. The counter electrode and the reference electrode are respectively disposed on the surface of the transparent optical substrate and electrically insulated from the metal functional layer; A microfluidic structure is sealed to the transparent optical substrate to form a reaction chamber for containing the liquid to be tested. The reaction chamber covers at least the overlapping area and the areas where the counter electrode and reference electrode are in contact with the liquid to be tested, and is provided with an inlet and an outlet communicating with the reaction chamber.

[0007] Furthermore, an adhesive layer is provided between the transparent optical substrate and the metal functional layer.

[0008] Furthermore, the counter electrode and the reference electrode together with the metal functional layer constitute a three-electrode system.

[0009] Furthermore, the metal functional layer is any one of a flat continuous film, a surface roughened film, a nanoporous film, or a nanostructured film, wherein the nanostructured film has electrical continuity.

[0010] Furthermore, the microfluidic structure includes one or more independent reaction chambers and is connected to at least one of a liquid storage container, a pump, a switching valve, a mixer, a concentration gradient generator, a bubble discharge structure, and a bypass flushing channel.

[0011] Based on the same inventive essence, this application also proposes a cositu electrochemical-surface plasmon resonance microfluidic interface detection system, which includes: The microfluidic chip; An optical detection module is used to generate an excitation beam and incident the excitation beam onto the metal functional layer to excite surface plasmon response in the overlapping region, and to acquire at least one optical parameter from the optical signals from the metal functional layer.

[0012] An electrochemical excitation module is electrically connected to the metal functional layer, counter electrode, and reference electrode of the microfluidic chip, and is used to apply electrochemical excitation to the metal functional layer and acquire the electrochemical response signal of the metal functional layer. A fluid control module, connected to the reaction chamber of the microfluidic chip, is used to introduce, discharge, or switch the liquid to be tested into the reaction chamber. The synchronization control and data processing module is connected to the optical detection module, the electrochemical excitation module and the fluid control module respectively, and is used to make the optical signal collected by the optical detection module and the electrochemical response signal collected by the electrochemical excitation module have a certain time correspondence, and to obtain the electrochemical-optical joint response result corresponding to the interface process based on the optical signal and the electrochemical response signal at the overlapping region.

[0013] Based on the same inventive essence, this application also proposes a method for interface detection using the aforementioned cositu electrochemical-surface plasmon resonance microfluidic interface detection system, comprising: S1: Introduce the liquid to be tested into the reaction chamber, so that the liquid to be tested comes into contact with the metal functional layer, the counter electrode and the reference electrode; S2: An excitation beam is incident on the metal functional layer through the optical detection module, and the optical signal of the overlapping area, i.e., the interface between the metal functional layer and the liquid to be tested, is collected. S3: Apply corresponding electrochemical excitation to the metal functional layer through the electrochemical excitation module, and simultaneously collect electrochemical response signals; S4: Based on the optical signal and the electrochemical response signal, obtain the electrochemical-optical joint response result corresponding to the interfacial process between the liquid under test and the metal functional layer.

[0014] Implementing the embodiments of the present invention will have the following beneficial effects: Firstly, this application employs the same continuous metal thin film as both the electrochemical working electrode and the SPR sensitive layer. The detection spot is located within the electrochemical active region, ensuring that the electrochemical reaction region and the SPR optical sensing region overlap on the same metal thin film surface. Compared to existing schemes where the electrochemical electrode and optical probe are spatially separated (resulting in a time phase difference between the current and optical signals due to the distance between them and the concentration gradient and mass transfer delay between the solution and the electrode interface), the current and optical signals in this application are acquired from the same interface under the same physical coordinates. They naturally possess time synchronization and require no spatial coordinate correction or time phase compensation. This structural design directly eliminates the unavoidable system-level spatial correspondence error inherent in separated schemes at the hardware level, providing a reliable guarantee for subsequent stage-based identification.

[0015] Secondly, this application employs a closed microfluidic channel structure covering the working electrode, counter electrode, and reference electrode, placing all three electrodes in the same closed liquid phase environment. This microfluidic reaction chamber provides a stable and low-consumption liquid phase environment for interface detection and facilitates liquid switching. The fluid volume can be controlled at the microliter level, significantly reducing the sample consumption of electrolyte and additives. The closed channel structure also allows the entire testing process to be carried out continuously under an inert atmosphere. By switching the sample introduction channel, different electrolytes can be sequentially introduced onto the same chip, enabling continuous testing under multiple conditions.

[0016] Third, this application simultaneously acquires electrochemical and optical responses, which can reduce misjudgments caused by evaluating interface states based on a single signal; the same platform can be adapted to different electrochemical programs, test solution formulations and fluid conditions, and can be used for the detection of interface processes such as energy storage, corrosion, electrodeposition, electrocatalysis, adsorption and surface functionalization. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] in: Figure 1 This is a block diagram of the cosine electrochemical-surface plasmon resonance microfluidic system corresponding to the scheme described in this invention; Figure 2(a) and Figure 2(b) are schematic diagrams of the top view and cross-sectional structure of the co-located microfluidic chip corresponding to the embodiments of the present invention; Figure 3 This is a flowchart of the interface in-situ detection and parameter screening method corresponding to the implementation case of the present invention.

[0019] In the figure: 1. Liquid to be tested; 2. Metal functional layer; 3. Adhesive layer; 4. Transparent optical substrate; 5. Optical coupling component; 6. Microfluidic structure; 7. Liquid inlet; 8. Liquid outlet; 9. Reference electrode; 10. Detection spot; 11. Counter electrode. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. It is understood that the terms “first,” “second,” etc., as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Both the first element and the second element are elements, but they are not the same element.

[0022] This invention essentially designs an integrated microfluidic chip that simultaneously serves as both an electrochemical working electrode and a surface plasmon resonance (SPR) optical sensing layer at the same location, and a cositu electrochemical-surface plasmon resonance microfluidic interface detection system based on this integrated microfluidic chip. The same continuous metal functional layer on the microfluidic chip serves as both the electrochemical working electrode and the surface plasmon resonance (SPR) sensitive layer, ensuring that the detection spot is located within the electrochemically active region of the working electrode, and that the microfluidic reaction chamber covers this cositu region, as well as the counter electrode and reference electrode. By synchronously controlling electrochemical excitation and optical acquisition, electrochemical and optical response data of the interface at the same location can be simultaneously obtained in a controlled liquid environment. Furthermore, this microfluidic chip should be adaptable to different liquid media and electrochemical processes, and the obtained responses should be used to study interfacial processes or compare different interfacial control conditions, enabling highly sensitive in-situ detection and analysis of different liquid media and interfacial processes.

[0023] Based on the above design framework, this embodiment proposes a co-situ electrochemical-surface plasmon resonance microfluidic chip, such as... Figure 1 - As shown in Figures 2(a) and 2(b), including: Transparent optical substrate 4; A metal functional layer 2 is disposed on the transparent optical substrate 4. A portion of the metal functional layer serves as an electrochemical working electrode in contact with the liquid to be tested, and this portion also serves as a surface plasmon resonance sensing layer. Another portion of the metal functional layer is an electrical connection lead-out area, used to electrically connect the electrochemical working electrode to an external circuit. That is, the projection of the detection spot 10 on the metal functional layer is located within the electrochemical active region of the electrochemical working electrode, thereby forming an overlapping region between the electrochemical region and the surface plasmon resonance optical sensing region. The counter electrode 11 and the reference electrode 9 are respectively disposed on the surface of the transparent optical substrate 4 and electrically insulated from the metal functional layer 2; The microfluidic structure 6 is sealed to the transparent optical substrate and forms a reaction chamber for containing the liquid to be tested. The reaction chamber covers at least the overlapping area and the area where the counter electrode and the reference electrode are in contact with the liquid to be tested, and is provided with an inlet and an outlet communicating with the reaction chamber.

[0024] Based on the above design, this invention proposes an integrated microfluidic electrochemical-surface plasmon resonance microfluidic chip. This invention enables multiple processes, including electrochemical excitation, SPR optical sensing, microfluidic reaction, and multi-source signal acquisition, to be completed on the same chip. Furthermore, it achieves co-situ integration of electrochemical excitation and SPR optical sensing on the same metal thin film surface. Specifically: First, the metal working electrode layer simultaneously serves as both the electrochemical working electrode and the SPR sensing layer. This ensures that the interfacial processes occurring within the electrochemical reaction region (the effective surface area where the metal functional layer directly contacts the liquid under test and can undergo an electrochemical reaction) and the local refractive index changes detected by the SPR sensing region both originate from the same physical spatial location of the interface. Compared to existing technologies that separate the electrochemical electrode and optical probe, this invention fundamentally eliminates the spatial correspondence error caused by separate electrodes and optical probes. This allows for precise alignment of the current response signal and the SPR resonant wavelength signal on the time axis, enabling the identification of nucleation initiation, deposition, and other stages of the interfacial film without the need for additional spatial coordinate correction or temporal phase compensation, thereby improving the reliability of in-situ detection results.

[0025] Secondly, the counter electrode, reference electrode, and working electrode are all covered by the reaction chamber of the microfluidic channel structure, ensuring that the three electrodes are in the same closed liquid phase environment. This arrangement not only ensures a uniform electric field distribution and stable reference potential, but also allows for precise control of the electrolyte volume, flow rate, and residence time within the channel. Simultaneously, it enables controllable additive switching, rinsing processes, and field-free recovery processes (reducing sample consumption while continuously detecting various liquid phase interface processes), thus guaranteeing the long-term stability and data comparability of co-location signal acquisition.

[0026] In summary, this invention can continuously and in real time capture the current change and SPR optical response at the same interface during electrochemical excitation, providing a reliable hardware structure for subsequent research on interface processes or comparison of different interface control conditions using the obtained response. Additionally, co-location refers to the spatial overlap between the electrochemical working electrode region and the surface plasmon resonance light spot irradiation region, allowing the same metal functional layer to simultaneously perform electrochemical sensing and optical sensing functions.

[0027] Based on the above design scheme, the following implementation case is provided for further explanation: Example 1: Cosmic Electrochemical-Surface Plasmon Resonance Microfluidic Interface Detection Chip As shown in Figure 2, the chip includes a transparent optical substrate, a metal functional layer, a counter electrode, a reference electrode, a microfluidic structure, electrical connection terminals, and an optical coupling interface. The transparent optical substrate can be formed of glass, quartz, sapphire or transparent polymer, preferably BK7 glass optical substrate, with a size of 1×2 cm and a thickness of 0.1 to 5 mm; and an adhesive layer 3 is provided on the surface of the transparent optical substrate, that is, the adhesive layer is provided between the transparent optical substrate and the metal functional layer; preferably, the adhesive layer is formed of chromium, titanium, nickel or a combination thereof, with a thickness of 0.5 to 10 nm; In this design, a portion of the metal functional layer serves as an electrochemical working electrode in contact with the liquid to be tested, while simultaneously acting as a surface plasmon resonance sensitive layer. The projection of the detection beam onto the metal functional layer lies within the electrochemical working electrode region of the working electrode. The surface of the metal functional layer corresponding to the beam projection is in direct contact with the liquid to be tested (the area of ​​the detection beam is 0.01–100 mm², and does not exceed the liquid contact area of ​​the working electrode), thereby forming an overlapping region between the optical sensing region and the electrochemical reaction region. This region can be formed from gold, silver, aluminum, copper, platinum, alloys of the above metals, or a conductive composite layer with a surface plasmon response, with a thickness of 30–100 nm. Preferably, the metal functional layer is made of gold, and its thickness in the prism coupling structure is preferably 40–60 nm. Preferably, the metal functional layer is any one of a flat continuous film, a surface roughened film, a nanoporous film, or a nanostructured film, wherein the nanostructured film has electrical continuity. Except for the region serving as the working electrode, the remaining portion of the metal functional layer is covered by an insulating layer to avoid direct contact with the liquid to be tested. In addition, after cleaning the transparent optical substrate, a chromium bonding layer and a gold functional layer are formed sequentially on its surface using magnetron sputtering mask deposition.

[0028] Another part of the metal functional layer serves as an electrical connection lead-out area. This electrical connection lead-out area is located outside the reaction chamber coverage area and is used to lead the working electrode (i.e., the part of the metal functional layer that is in contact with the liquid to be tested) to the outside of the chip to connect to the electrochemical excitation module. Since the electrical connection lead-out area and the working electrode are composed of the same continuous metal functional layer and are integrally formed without any redundant physical interfaces, the continuity of electrical signal transmission can be ensured. Furthermore, since the electrical connection lead-out area is located outside the reaction chamber covered by the microfluidic structure, it can effectively avoid electrochemical interference caused by contact between the electrical connection lead-out area and the liquid to be tested.

[0029] The counter electrode and reference electrode together with the metal functional layer constitute a three-electrode system. Specifically, a platinum reference electrode and a platinum counter electrode are formed on both sides of the metal functional layer, and the metal functional layer, reference electrode, and counter electrode are mutually insulated and each has an electrical connection terminal. Preferably, the reference electrode, the metal functional layer, and the counter electrode are arranged sequentially and spaced apart along the reaction chamber. The distance between the reference electrode and the metal functional layer is 0.05–10 mm, and the effective area of ​​the working electrode can be 0.1–500 mm², with the reference electrode close to the working electrode. Preferably, the counter electrode and reference electrode are platinum films, which can be formed by mask deposition, photolithography, printing, transfer, or assembly, with a film thickness of 5–30 nm. For example, the chromium bonding layer thickness can be 3 nm, the metal functional layer thickness 50 nm, and the platinum film thickness of the counter electrode and reference electrode 15 nm, forming a RE-WE-CE electrode layout, where the reference electrode is close to the working electrode to reduce the influence of IR drop on potential measurement. The above values ​​represent a feasible setting; the actual thickness can be dynamically adjusted based on the optical coupling method, electrochemical stability, and fabrication process. Furthermore, in this three-electrode system, the metal working electrode layer is a multifunctional integrated layer serving two purposes: firstly, it acts as an electrochemical working electrode (WE), used to apply electrochemical excitation signals to the interface and bear interfacial reactions (such as double-layer charging, electrolyte reduction, interfacial film nucleation, and deposition growth processes); secondly, it simultaneously serves as an SPR-sensitive layer, forming a metal-dielectric optical interface together with the optical substrate and the contacting electrolyte. Utilizing the transient response characteristics of surface plasmon resonances to changes in effective optical thickness and refractive index at the interface, it can then acquire optical signals corresponding to the evolution of the interfacial film structure in real time.

[0030] Therefore, it can be said that this invention eliminates the design concept of placing the electrochemical reaction region and the SPR optical sensing region in two separate regions, and positions them together on the same metal thin film surface. Based on this, it ensures that the current signal and the optical signal are collected from the same interface of the same physical spatial coordinates and there are no problems such as acquisition time delay. Thus, when acquiring electrochemical-optical multi-source signals, this invention does not need to consider additional spatial coordinate registration steps or time phase compensation algorithms, and directly eliminates time / space errors at the hardware level.

[0031] The microfluidic structure is sealed to the optical substrate and forms a reaction chamber, which at least covers the overlapping region and the areas where the counter electrode and reference electrode are in contact with the liquid. Specifically, it includes one or more independent reaction chambers and is connected to at least one of a reservoir, a pump, a switching valve, a mixer, a concentration gradient generator, a bubble discharge structure, and a bypass flushing channel.

[0032] Preferably, the microfluidic structure is provided with an inlet 7 and an outlet 8 to introduce, discharge, or switch the liquid to be tested. It can be connected to a storage container, pump, switching valve, mixer, bubble discharge structure, or multiple parallel channels. As described, the microfluidic structure is made of corrosion-resistant polytetrafluoroethylene (PTFE) and has an internal reaction chamber for containing electrolyte. The height of the reaction chamber is 20 μm to 2 mm, the width is 0.2 to 20 mm, and the volume is 0.1 μL to 1 mL. The inner diameter of the inlet and outlet is 50 μm to 5 mm. These ranges can be adjusted according to the sample volume, mass transfer rate, sealing method, and detection spot size.

[0033] Preferably, the microfluidic structure can form a single reaction chamber or multiple independent reaction chambers; and is connected to at least one of a liquid storage container, a pump, a switching valve, a mixer, a concentration gradient generator, a bubble discharge structure, and a bypass flushing channel, and is mechanically clamped to form a micro-level closed reaction space with a sealing gasket and the optical substrate.

[0034] For example, the microfluidic structure uses a polytetrafluoroethylene single-channel flow cell. The height of the reaction chamber can be 20 μm to 2 mm, the width can be 0.2 to 20 mm, and the volume can be 0.1 μL to 1 mL. The distance between the working electrode and the reference electrode can be 0.05 to 10 mm. The detection spot area can be 0.01 to 100 mm². The inlet can be connected to one or more storage containers and can be equipped with a pump, switching valve, mixer, concentration gradient generator, bubble discharge structure, or bypass flushing channel to achieve quantitative delivery and switching of the test liquid. The side of the transparent optical substrate facing away from the metal functional layer is connected to a prism-shaped optical coupling component to couple the excitation light to the gold film interface to excite the SPR effect. Therefore, optical detection and electrochemical testing are performed on the same local interface, and each electrode has an electrical connection terminal for connecting to external electrochemical testing equipment. Alternatively, the microfluidic structure may include multiple independent reaction channels, each reaction chamber covering its corresponding overlapping area, counter electrode, and reference electrode contact area, to enable parallel operation of multiple sets of experiments, facilitating high-throughput parallel screening of different formation parameters or electrolyte formulations on the same chip; the aforementioned multi-channel flow structure is connected to the optical substrate in a sealed manner through compression, bonding, mechanical clamping, or sealing gaskets.

[0035] Combining the solutions of the two embodiments above, the update rate of the electrolyte in the sensing area can be precisely controlled by controlling the flow channel volume, flow rate and residence time of the reaction cavity; by switching different storage bottles or sample introduction channels, reference electrolyte, additive electrolyte and rinsing solution can be introduced sequentially or selectively on the same chip, thereby realizing continuous testing under multiple conditions and parameters.

[0036] Based on the same inventive essence, the present invention also provides a cositu electrochemical-surface plasmon resonance microfluidic interface detection system, comprising: The aforementioned microfluidic chip; An optical detection module is used to generate an excitation beam and incident the excitation beam onto the metal functional layer to excite surface plasmon response in the overlapping region, and to acquire at least one optical parameter from the optical signals from the metal functional layer.

[0037] The optical detection module includes a light source, an optical path adjustment component, an optical coupling component 5, and a spectrum acquisition device. The light source is used to generate an excitation beam, the optical path adjustment component is used to adjust the propagation direction, polarization state, and spot position of the excitation beam, the optical coupling component is used to couple the excitation beam to the overlapping region to excite the surface plasmon response, and the spectrum acquisition device is used to receive optical signals from the metal functional layer and acquire at least one optical parameter among the resonant wavelength, resonant angle, reflection intensity, spectral line shape, or phase. Preferably, the light source is at least one of halogen lamp, deuterium halogen lamp, light-emitting diode, laser, broadband light source or supercontinuum light source, and the output wavelength of the light source covers at least a portion of 250 to 2500 nm. Preferably, the optical path adjustment component includes at least one of an optical fiber, a collimator, a polarizer, a filter, a beam splitter, a mirror, and a focusing component; the excitation light is incident on the overlapping region of the metal functional layer in the form of P-polarized light, and the detection spot area is 0.01 to 100 mm².

[0038] Preferably, the optical coupling component is any one of a prism coupler, a grating coupler, a waveguide coupler, or a fiber optic coupler; the light source wavelength can be 250–2500 nm, the optical signal sampling interval can be 0.01–60 s, and the single integration time can be 1 ms–10 s.

[0039] Preferably, the spectral acquisition device is a fiber optic spectrometer, an array spectrometer, a scanning spectrometer, or an imaging spectrometer; its integration time is 1 ms to 10 s, the average number of times a single spectrum is 1 to 100, and the continuous sampling interval is 0.01 to 60 s.

[0040] An electrochemical excitation module is electrically connected to the metal functional layer, counter electrode, and reference electrode of the microfluidic chip, and is used to apply electrochemical excitation to the metal functional layer and acquire the electrochemical response signal of the metal functional layer. The electrochemical excitation module includes at least one of a constant potential control unit, a constant current control unit, a current acquisition unit, and an impedance testing unit; the corresponding electrochemical excitation is selected from at least one of cyclic voltammetry, linear scan, constant potential, constant current, pulse, or impedance testing; the electrochemical signal is selected from at least one of current, potential, charge, or impedance. Preferably, its potential control range is -5 to 5 V relative to the reference electrode, its current detection range is 1 nA to 1 A, and its scan rate is 10. -5 ~10 V / s, impedance test frequency is 10 - ³~10 6 Hz.

[0041] A fluid control module, connected to the reaction chamber of the microfluidic chip, is used to introduce, discharge, or switch the test liquid 1 into the reaction chamber; The fluid control module includes at least one of a liquid storage container, a syringe pump, a peristaltic pump, a pressure pump, a switching valve, a mixer, a temperature control component, and a bubble discharge structure; the preferred flow rate of the test liquid is 0.1 μL / min to 10 mL / min, and the detection temperature is 0 to 80℃.

[0042] The synchronization control and data processing module is connected to the optical detection module, the electrochemical excitation module and the fluid control module respectively, and is used to make the optical signal collected by the optical detection module and the electrochemical response signal collected by the electrochemical excitation module have a certain time correspondence, and to obtain the electrochemical-optical joint response result corresponding to the interface process based on the optical signal and the electrochemical response signal at the overlapping region.

[0043] The synchronization control and data processing module establishes a defined temporal correspondence between the optical signal, electrochemical signal, and fluid operation through a common trigger signal, a common clock, or timestamped data recording. It performs baseline processing, time alignment, and feature extraction on the signals, extracting at least two parameters from the optical and electrochemical signals to form the electrochemical-optical joint response result. These parameters include at least two from resonance wavelength, resonance angle, reflection intensity, spectral line shape, phase, current, potential, charge, and impedance. Furthermore, the signal processing by the synchronization control and data processing module involves only baseline processing, signal alignment, feature extraction, and conditional comparison, without requiring fixed stage divisions of the interface process or relying on specific empirical formulas or complex algorithms. This significantly differs from traditional data processing methods that require pre-dividing the interface formation stages and establishing separate mathematical models for each stage, thus improving versatility.

[0044] Based on the same inventive essence, this invention also provides a method for interface detection using the aforementioned system. The test liquid is introduced into the reaction chamber, contacting the metal functional layer, the counter electrode, and the reference electrode. Subsequently, an electrochemical excitation is applied to the metal functional layer, and the surface plasmon response and electrochemical response of the overlapping region are simultaneously acquired to obtain the electrochemical-optical joint response results corresponding to the interfacial process between the test liquid and the metal functional layer. When condition screening is required, different interface control conditions are repeatedly tested, and the corresponding joint response results are compared.

[0045] Specifically, such as Figure 3 It includes: S1: Introduce the liquid to be tested into the reaction chamber, so that the liquid to be tested comes into contact with the metal functional layer, the counter electrode and the reference electrode; S2: An excitation beam is incident on the metal functional layer through the optical detection module, and the optical signals, such as reflection spectrum, emission spectrum or light intensity signal, are collected at the interface between the metal functional layer and the liquid to be tested, i.e., the overlapping area. S3: Apply corresponding electrochemical excitation to the metal functional layer through the electrochemical excitation module, and simultaneously collect electrochemical response signals, such as synchronously collecting current, potential, charge or impedance signals, etc. S4: Based on the optical signal and the electrochemical response signal, obtain the electrochemical-optical joint response result corresponding to the interface process between the liquid under test and the metal functional layer. The interface process includes at least one of the following: interface product generation, deposition and dissolution, adsorption and desorption, corrosion, passivation, electrodeposition, electrocatalysis, interface polymerization, surface functionalization, and formation of a battery solid electrolyte interface film or a positive electrode electrolyte interface film.

[0046] Preferably, optical acquisition parameters, electrochemical excitation parameters, and fluid control parameters are set before detection, and the optical detection module, electrochemical excitation module, and fluid control module are kept in time synchronization. Preferably, before applying electrochemical excitation, initial optical signals and initial electrochemical signals are acquired under conditions of open circuit, constant potential, or no target interface reaction, and the initial optical signals and initial electrochemical signals are used as the interface detection baseline.

[0047] Preferably, at least two sets of interface control conditions to be compared are set, and the interface detection is performed on each set of interface control conditions. Based on the electrochemical-optical joint response results of each set, the interface control conditions or candidate conditions that meet the preset target are output in order. The interface control conditions include at least one of the following: potential, current, scan rate, electrochemical excitation duration, pulse parameters, number of cycles, settling time, type of test liquid, reactant components, type of additive, additive content, flow rate, temperature, and pressure. For example, the flow rate can be 0.1 μL / min to 10 mL / min, and the detection temperature can be 0 to 80 ℃. Different conditions can be tested on different chips, or they can be tested sequentially or in parallel on the same chip through a multi-reaction chamber or liquid switching structure.

[0048] Preferably, the electrochemical-optical joint response result includes at least one optical response feature and at least one electrochemical response feature; the optical response feature is selected from at least one of the following: resonance wavelength, resonance angle, reflection intensity, change in spectral line shape or phase, rate of change, response time, residual change, and reversible change; the electrochemical response feature is selected from at least one of the following: current, potential, charge, inter-cycle current change, and impedance. Specific features can be selected according to the detection target, without the need to calculate all parameters. When calibrating using a standard layer with known refractive index and thickness, the optical response can be converted into the effective optical thickness of the interface layer; the effective optical thickness suitable for monitoring can be 0.1–300 nm. When exceeding the effective detection depth of surface plasmons, saturation response or other interface characterization results can be used to assist in the judgment.

[0049] In addition, the surface plasmon resonance optical signal and the electrochemical response signal are collected after potential switching, electrochemical excitation cessation, switching of the test liquid, or standing, in order to obtain the subsequent response of the interface.

[0050] Furthermore, this invention does not require a specific material system or a specific interface film as a prerequisite for detection, nor does it require dividing the interface process into a fixed number or fixed sequence of stages. The direction of the optical signal reflects the comprehensive result of multiple interface optical contributions, and does not solely determine the specific reaction mechanism or interface product composition based on a single redshift or blueshift. When it is necessary to determine the product composition, it can be further combined with spectral, microscopic, or other material characterization results. Detectable interface processes include interface product formation, deposition and dissolution, adsorption and desorption, surface passivation, corrosion, electrodeposition, electrocatalytic reactions, interfacial polymerization, and structural adjustment. By changing candidate conditions such as electrochemical excitation, test solution composition, reaction time, number of cycles, fluid conditions, or temperature, and comparing the corresponding electrochemical-optical responses, it can be used for interface process research, material evaluation, and process parameter screening. That is, the detection of solid electrolyte interface films in batteries is only one application of this invention.

[0051] Based on the above design scheme, the following implementation case is provided for further explanation: Example 2: A cositu electrochemical-surface plasmon resonance microfluidic interface detection system, comprising: like Figure 1 As shown, the microfluidic chip, optical detection module, electrochemical excitation module, fluid control module, and synchronous control and data processing module are described above. The optical detection module includes a broadband light source, polarization and collimation components, and a spectral acquisition device. The electrochemical excitation module uses an electrochemical workstation. The fluid control module includes a liquid storage container, pipelines, and a pump. The synchronous control and data processing module is used to record the spectral acquisition time, the electrochemical program time, and the fluid operation time, and saves the corresponding data as a single test record.

[0052] To verify the electrochemical performance of the chip, 1 mmol / L potassium ferricyanide was dissolved in 0.1 mol / L potassium chloride solution and introduced into the reaction chamber. Cyclic voltammetry was performed within the potential range of -0.4 to 0.4 V. The chip achieved stable redox responses at different scan rates, indicating that it can perform electrochemical excitation and current acquisition. To verify the optical detection performance of the chip, sodium chloride solutions with different refractive indices were sequentially introduced into the reaction chamber without electrochemical excitation. As the refractive index of the test solution increased, the SPR resonance position redshifted; after re-introducing the reference solution, the resonance position recovered. The refractive index sensitivity measured by the system was approximately 1646 nm / RIU. These results demonstrate that the chip can simultaneously perform electrochemical testing and surface plasmon interface detection in a closed microfluidic environment, and can synchronously acquire the electrochemical and optical responses of the same interface.

[0053] Example 3: Testing was conducted using a cositu electrochemical-surface plasmon resonance microfluidic interface detection system, which includes: Interface detection operation: The test solution is introduced into the reaction chamber, and the initial optical and electrochemical baselines are recorded under open-circuit, constant potential, or no target reaction conditions. A predetermined electrochemical program is then applied, and current, potential, and surface plasmon response are recorded simultaneously. After potential reversal, electrochemical program termination, test solution switching, or settling, the interface recovery, residual changes, or subsequent reactions are recorded. By changing the test solution composition, excitation method, reaction time, flow rate, or temperature, the interface response under different conditions can be compared. In this embodiment, the flow rate can be selected from 0.1 μL / min to 10 mL / min, the detection temperature from 0 to 80 °C, and the optical sampling interval from 0.01 to 60 s. For rapid electrodeposition or electrocatalytic processes, shorter sampling intervals can be used; for slow corrosion, passivation, or adsorption processes, the sampling frequency can be reduced and the monitoring time extended. The above operation does not require a fixed number or sequence of stages in the interface process.

[0054] SEI film formation monitoring: A lithium-containing carbonate electrolyte is introduced into the reaction chamber. After obtaining a stable baseline in an open-circuit state, cyclic voltammetry programs with different scan rates are applied to the working electrode, and the current and SPR resonance position are recorded simultaneously. After each set of tests, the static response is recorded and impedance tests are performed. The SEI film formed at the interface can be located within an effective monitoring range of approximately 1–300 nm. In the gold model interface of this invention, the SEI film thickness measured by offline atomic force microscopy is approximately 85–140 nm, which can be used as an example to verify the optical response, but it does not limit the chip to only detect this thickness range or this type of film. The comparative results show that the condition with the greatest optical change does not necessarily have the most suitable electrochemical response; among the candidate conditions in this embodiment, a moderate scan rate has a good balance between the degree of interfacial reaction and impedance. Therefore, this system can use the combined electrochemical and optical response to eliminate misjudgments based solely on the maximum value of a single signal as the optimal condition.

[0055] A mixed electrolyte of ethylene carbonate / methyl ethyl carbonate containing 1 mol / L lithium hexafluorophosphate is introduced into the reaction chamber, wherein the volume ratio of ethylene carbonate to methyl ethyl carbonate is 3:7. Initial optical signals are acquired in an open-circuit state. Subsequently, using a platinum reference electrode as a reference, cyclic voltammetry is performed within a potential range of 0 to -2 V at a scan rate of 0.0025 to 0.04 V / s, while simultaneously acquiring current signals and SPR resonance position changes. After the potential scan is completed, the optical response during the resting process is acquired, and impedance testing is performed as needed. This embodiment uses a co-location detection chip composed of BK7 glass, a 3 nm chromium bonding layer, and a 50 nm gold functional layer. After rinsing and drying under an inert atmosphere, the chip is examined using offline atomic force microscopy. The measured SEI equivalent film thickness at the gold model interface is approximately 85–140 nm, which is within the effective near-field range for surface plasmon resonance detection in this embodiment. The above film thickness data is used to illustrate that the chip can respond to nanoscale interface layer changes, and does not imply that the present invention is only applicable to SEI films, nor does it imply that an uncalibrated SPR resonance position can be directly equated to the geometric thickness of the interface layer. Resonance position changes, reduction current, charge response, and impedance were compared under different scan rates and cycle numbers. The results show that a large resonance position change does not necessarily correspond to a lower interface impedance or a better interface state; simultaneously acquiring electrochemical and optical responses helps avoid evaluating the interface process based solely on a single endpoint signal. In electrolyte composition detection, a reference electrolyte, an electrolyte containing vinylene carbonate, and an electrolyte containing fluorinated ethylene carbonate can be introduced into the reaction chamber, respectively. The reduction potential, current response, and resonance position changes differ for different electrolytes. This embodiment is used to illustrate that the chip can detect SEI film formation and does not constitute a limitation on the test solution, additives, or battery system.

[0056] In another set of tests, a reference electrolyte and electrolytes containing either vinylene carbonate or fluoroethylene carbonate were sequentially introduced into the reaction chamber. Different electrolytes produced different reduction potentials, current responses, and SPR changes, allowing for comparison of the effects of additives on the interfacial reaction. This example is for illustrative purposes only and does not constitute a necessary limitation of this scheme by specifying any particular additive, lithium battery system, or SEI film.

[0057] Metal deposition, corrosion and passivation detection: In metal deposition detection, a solution containing the metal ions to be deposited is introduced into the reaction chamber. A constant potential, linear scan, or pulsed potential is applied to the functional metal layer. The stability of deposition initiation, accumulation, and cessation is characterized by the changes in deposition current and resonant position. By adjusting the ion concentration, potential, pulse duty cycle, and flow rate, uniform deposition conditions can be screened.

[0058] In corrosion or passivation testing, the functional metal layer is exposed to acid, alkali, salt solutions, or media containing corrosion inhibitors, and the open-circuit potential, polarization current, and surface plasmon response are recorded. By switching between a blank medium and a medium containing corrosion inhibitors, the surface dissolution, passivation layer formation, and reactivation processes can be compared. The interface layer under test can be an oxide, hydroxide, salt, organic protective layer, or a composite layer thereof.

[0059] Adsorption, electrocatalysis and surface functionalization detection: In adsorption or surface functionalization detection, the analyte containing molecules, polymers, particles, or biorecognition components is introduced into the reaction chamber. Through open-circuit, potential-controlled, or electrochemical polymerization, it interacts with the metal functional layer, and the electrochemical response and interfacial refractive index changes are recorded simultaneously. In electrocatalysis detection, reactant concentration, potential program, flow rate, and temperature can be varied to compare catalytic interface activation, adsorption intermediate accumulation, and surface deactivation. All the above implementations utilize the same co-located chip and do not require an SEI film.

[0060] Furthermore, this application allows for selection based on specific applications; it does not require the use of all methods, nor does it directly interpret a single optical change as a specific chemical composition or film quality. When calibrating using a standard layer with known refractive index and thickness, the optical response can be converted into the effective optical thickness of the interface layer. The preferred effective optical thickness of the interface layer for monitoring is 0.1–300 nm. When the effective detection depth of surface plasmons is exceeded, saturation response or other characterization methods are used to assist in the judgment.

[0061] Based on the same inventive concept, the present invention also proposes a computer-readable storage medium including computer instructions that, when executed on a computer, cause the computer to perform the method described thereon.

[0062] Based on the same inventive concept, the present invention also proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method when executing the program.

[0063] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A cositu electrochemical-surface plasmon resonance microfluidic interface detection chip, characterized in that, include: Transparent optical substrate; A metallic functional layer is disposed on the transparent optical substrate. A portion of the metallic functional layer serves as an electrochemical working electrode in contact with the liquid to be tested, and this portion also serves as a surface plasmon resonance sensing layer. Another portion of the metallic functional layer is an electrical connection lead-out area for electrically connecting the electrochemical working electrode to an external circuit. That is, the projection of the detection spot on the metallic functional layer is located within the electrochemically active region of the electrochemical working electrode, thereby forming an overlap between the electrochemical region and the surface plasmon resonance optical sensing region. Furthermore, the area of ​​the detection spot does not exceed the area of ​​the electrochemically active region in contact with the liquid to be tested. Except for the region serving as the electrochemical working electrode, the remaining portion of the metallic functional layer is covered by an insulating layer to avoid direct contact with the liquid to be tested. The electrical connection lead-out area is disposed outside the reaction chamber covered by the microfluidic structure. The counter electrode and the reference electrode are respectively disposed on the surface of the transparent optical substrate and electrically insulated from the metal functional layer; A microfluidic structure is sealed to the transparent optical substrate to form a reaction chamber for containing the liquid to be tested. The reaction chamber covers at least the overlapping area and the areas where the counter electrode and reference electrode are in contact with the liquid to be tested, and is provided with an inlet and an outlet communicating with the reaction chamber.

2. The cosmochemical-surface plasmon resonance microfluidic interface detection chip according to claim 1, characterized in that, An adhesive layer is provided between the transparent optical substrate and the metal functional layer.

3. The cosmochemical-surface plasmon resonance microfluidic interface detection chip according to claim 1, characterized in that, The counter electrode and reference electrode together with the metal functional layer constitute a three-electrode system.

4. The cosmochemical-surface plasmon resonance microfluidic interface detection chip according to claim 1, characterized in that, The metal functional layer is any one of a flat continuous film, a surface roughened film, a nanoporous film, or a nanostructured film, wherein the nanostructured film has electrical continuity.

5. The cosmochemical-surface plasmon resonance microfluidic interface detection chip according to claim 1, characterized in that, The microfluidic structure includes one or more independent reaction chambers and is connected to at least one of a liquid storage container, a pump, a switching valve, a mixer, a concentration gradient generator, a bubble discharge structure, and a bypass flushing channel.

6. A cositu electrochemical-surface plasmon resonance microfluidic interface detection system, characterized in that, include: A microfluidic chip, wherein the microfluidic chip is the chip according to any one of claims 1 to 5; An optical detection module is used to generate an excitation beam and incident the excitation beam onto the metal functional layer to excite surface plasmon response in the overlapping region, and to acquire at least one optical parameter from the optical signals from the metal functional layer. An electrochemical excitation module is electrically connected to the metal functional layer, counter electrode, and reference electrode of the microfluidic chip, and is used to apply electrochemical excitation to the metal functional layer and acquire the electrochemical response signal of the metal functional layer. A fluid control module, connected to the reaction chamber of the microfluidic chip, is used to introduce, discharge, or switch the liquid to be tested into the reaction chamber. The synchronization control and data processing module is connected to the optical detection module, the electrochemical excitation module and the fluid control module respectively, and is used to make the optical signal collected by the optical detection module and the electrochemical response signal collected by the electrochemical excitation module have a certain time correspondence, and to obtain the electrochemical-optical joint response result corresponding to the interface process based on the optical signal and the electrochemical response signal at the overlapping region.

7. The cositu electrochemical-surface plasmon resonance microfluidic interface detection system according to claim 6, characterized in that, An optical detection module includes a light source, an optical path adjustment component, an optical coupling component, and a spectral acquisition device. The light source is used to generate an excitation beam, the optical path adjustment component is used to adjust the propagation direction, polarization state, and spot position of the excitation beam, the optical coupling component is used to couple the excitation beam to the overlapping region to excite the surface plasmon response, and the spectral acquisition device is used to receive optical signals from the metal functional layer and acquire at least one optical parameter.

8. The cositu electrochemical-surface plasmon resonance microfluidic interface detection system according to claim 6, characterized in that, The optical parameters are at least one of the following: resonance wavelength, resonance angle, reflection intensity, spectral line shape, or phase; the electrochemical excitation is at least one of the following: cyclic voltammetry, linear scan, constant potential, constant current, pulse, or impedance testing; and the electrochemical response signal is at least one of the following: current, potential, charge, or impedance.

9. The cositu electrochemical-surface plasmon resonance microfluidic interface detection system according to claim 6, characterized in that, The synchronization control and data processing module establishes a definite time correspondence between the optical signal, electrochemical signal, and fluid operation through a common trigger signal, a common clock, or data recording with timestamps. The synchronization control and data processing module extracts at least two parameters from the optical signal and the electrochemical signal to form the electrochemical-optical joint response result.

10. A method for interface detection using the cositu electrochemical-surface plasmon resonance microfluidic interface detection system as described in claim 6, characterized in that, include: S1: Introduce the liquid to be tested into the reaction chamber, so that the liquid to be tested comes into contact with the metal functional layer, the counter electrode and the reference electrode; S2: An excitation beam is incident on the metal functional layer through the optical detection module, and the optical signal of the overlapping area, i.e., the interface between the metal functional layer and the liquid to be tested, is collected. S3: Apply electrochemical excitation to the metal functional layer through the electrochemical excitation module, and simultaneously collect electrochemical response signals; S4: Based on the optical signal and the electrochemical response signal, obtain the electrochemical-optical joint response result corresponding to the interfacial process between the liquid under test and the metal functional layer.

Images