Weak measurement imaging detection method and device for rapidly screening working electrode of flow battery

Abstract

The invention relates to the technical field of detection of electrode material performance characterization, in particular to a weak measurement imaging detection method and device for rapidly screening a working electrode of a flow battery. The method comprises the following steps: performing real-time detection on electrode surface imaging and electrolyte refractive index by a weak measurement imaging system, obtaining the distribution condition of electrode surface activity parameters through deconvolution operation, and performing statistical fitting on the obtained parameters so as to judge the performance of the working electrode, thereby achieving the effect of rapid screening. The weak measurement imaging system detection device is combined with the potential scanning system to perform in-situ detection on the surface activity of the electrode, so that the operation is simple and convenient, in-situ, real-time and effective electrode activity distribution can be obtained, a large amount of activity parameter data can be obtained, batch electrodes are replaced by detecting a single electrode, and the detection efficiency is improved. And a detection tool is provided for electrode modification and screening.

Description

Technical Field

[0001] The present invention relates to the field of detection technology for characterizing the performance of electrode materials in energy systems. More specifically, it relates to a weak measurement imaging detection method and device for rapidly screening working electrodes of liquid flow batteries. The method can realize surface imaging of liquid flow battery electrodes and in-situ detection of current density distribution during battery operation, and can extract activity parameters. Background Art

[0002] Liquid flow batteries (FBs) are a technology route that is currently widely used in commercial applications and accounts for a relatively high proportion of grid-level energy storage investment. They have attracted much attention due to their inherent safety, ultra-long cycle life, and modular scalability. For example, vanadium liquid flow batteries (VRFBs) have become the mainstream choice due to their unique cross-contamination-free characteristics, but their high cost has always restricted the scale-up process. The core of cost reduction in liquid flow battery technology lies in the simultaneous improvement of power density and energy conversion efficiency, and the research on working electrode materials is the key breakthrough to break through the bottleneck of existing technologies. Therefore, the development of simple and efficient electrode performance screening methods is of great significance. It will provide technical support for the rapid identification of high-performance electrode materials, thereby accelerating the research and development of advanced liquid flow battery systems and promoting the development of energy storage technology towards higher performance and lower cost.

[0003] The current industrial testing and screening process for flow battery electrodes mainly relies on large-scale random sampling, combined with a multi-dimensional evaluation system. This system involves standard testing, material characterization, and engineering verification. The testing includes key performance indicators such as electrode thickness, resistivity, and hydrophilicity. At the same time, it uses advanced characterization technologies such as scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) to meet the diverse needs of all-vanadium flow batteries and other types of flow batteries. However, this also brings a higher cost burden and operational complexity.

[0004] Evanescent wave optical detection methods are widely used in the biomedical field due to their high sensitivity, high resolution, and in-situ non-destructive testing capabilities. They can detect refractive index changes at interfaces in real time and measure the current density of electrochemical reactions. For example, our published patent applications 201811617909.6 (A method and device for online detection of localized reaction activity in flow battery electrodes) and 201910060777.X (A method and device for in-situ detection of current density distribution in flow battery electrodes) utilize surface plasmon resonance technology to characterize electrode activity and total reflection imaging technology to perform in-situ detection of current density distribution during battery operation.

[0005] In order to further improve the efficiency and accuracy of imaging the surface of flow battery electrodes and in-situ detection of current density distribution during battery operation, it is necessary to improve existing technologies to reduce operational complexity. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a weak measurement imaging detection method and device for rapid screening of working electrodes of liquid flow batteries.

[0007] According to a first aspect of the present invention, a method for rapid screening of weak measurement imaging detection of working electrodes of a flow battery is provided, the method comprising the following steps:

[0008] Apply a cyclic voltammetry scanning signal to the electrochemical workstation to drive the working electrode to undergo redox reaction;

[0009] During the redox reaction of the working electrode, the characteristic light intensity signal generated by the dynamic change of the refractive index of the electrolyte is captured in real time by a weak measurement imaging system and converted into current density distribution data. At the same time, the response current value output by the electrochemical workstation is synchronously collected to construct a function model of the ratio of current density to integral current. The effective active area of the working electrode is then obtained through algorithmic iterative optimization calculation, and all reaction activity parameters in the effective active area are extracted.

[0010] According to a second aspect of the present invention, a weak measurement imaging detection device for rapidly screening working electrodes of a flow battery is provided. The device comprises an electrochemical workstation and a weak measurement imaging detection system, wherein:

[0011] The electrochemical workstation is used to apply a cyclic voltammetry scanning signal to drive the working electrode to be tested to undergo an oxidation-reduction reaction;

[0012] The weak measurement imaging detection system is used to capture the characteristic light intensity signal generated by the dynamic change of the refractive index of the electrolyte in real time during the redox reaction of the working electrode, convert the characteristic light intensity signal into current density distribution data, and simultaneously collect the response current value output by the electrochemical workstation, construct a ratio function model of current density and integrated current, and then obtain the effective active area of the working electrode through algorithm iterative optimization calculation, and extract all reaction activity parameters in the effective active area.

[0013] Compared with the prior art, the advantage of the present invention is that, based on the total reflection imaging system, a more sensitive weak measurement imaging system is used in combination with an electrochemical workstation to perform in-situ detection of the electrode reaction activity distribution, which can more accurately obtain the active area actually participating in the electrochemical reaction and the values of the electrochemical activity parameters of each part. The provided weak measurement imaging detection scheme for rapid screening of liquid flow battery working electrodes uses two liquid flow battery electrode materials (graphite felt and heat-activated graphite felt) as examples to study the electrode reaction activity distribution of electrode materials and extract the activity parameters of each part. A camera is selected to detect the refractive index of the electrolyte during the cyclic voltammetry of the electrode, and then obtain the electrode current density, which is combined with the current obtained by the electrochemical workstation to finally obtain the reaction activity distribution of the electrode, and extract the redox activity parameters of the electrode surface. The present invention provides a technical tool for characterizing the activity of electrodes participating in electrochemical reactions and efficiently screening liquid flow battery working electrodes.

[0014] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0016] Figure 1 is a flow chart of a method for in-situ detection of active areas of electrode materials participating in electrochemical reactions according to one embodiment of the present invention;

[0017] Figure 2 2 is a schematic diagram of a weak measurement imaging detection device for simply and efficiently screening excellent working electrodes of a flow battery according to an embodiment of the present invention;

[0018] Figure 3 is a schematic diagram of obtaining the reaction activity distribution of an electrochemical reaction and acquiring quantitative data by using a weak measurement imaging system during a cyclic voltammetry process or a linear sweep voltammetry process according to one embodiment of the present invention;

[0019] Figure 4 2. It is a schematic diagram of the results of a calibration experiment of light intensity and current of a uniformly adjustable stone mill plate electrode according to one embodiment of the present invention;

[0020] Figure 5 Schematic diagram of a weak measurement imaging system according to one embodiment of the present invention detecting an electrode material participating in an electrochemical reaction during a cyclic voltammetry process, ultimately obtaining a reaction activity distribution of the electrode and extracting redox activity parameters of the electrode surface;

[0021] Figure 6 According to one embodiment of the present invention, two working electrodes are placed in Figure 5Schematic diagram of linear fitting comparison between the redox activity parameters extracted and the data obtained by the electrochemical workstation;

[0022] In the accompanying drawings, 11 is an LED light source; 12 is a collimating lens; 13 is a front polarizer; 14 is an optical rotator; 15 is a λ / 4 achromatic wave plate; 16 is a prism; 17 is a polarizer; 18 is a CMOS camera; 21 is an electrode to be tested; 22 is a titanium wire; 23 is a graphite rod; 24 is a saturated calomel electrode; 25 is a container; 26 is an electrochemical workstation; 31 is a computer for receiving the curve of the electrochemical workstation; 32 is a computer for fitting the redox peak current distribution; 33 is a computer for fitting the redox peak current distribution; 34 is a computer for deconvolution of the light intensity data. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

[0024] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0025] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0026] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0027] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0028] The present invention proposes an in-situ detection method for measuring the distribution of electrode activity in electrochemical reactions and obtaining the numerical values of reaction activity parameters at each location. This is an in-situ detection method for electrode active area based on multi-physical field coupling. Generally speaking, during the process of applying a cyclic voltammetry scanning signal to the electrochemical workstation to drive the working electrode to undergo a redox reaction, the characteristic light intensity signal generated by the dynamic change of the electrolyte refractive index is captured in real time by an integrated optical sensing module, and the optical parameters are converted into current density distribution data through a signal conversion algorithm; at the same time, the response current value output by the electrochemical workstation is synchronously collected, and a function model of the ratio of current density to integrated current is constructed. The effective active area of the electrode is obtained through algorithmic iterative optimization calculation, and all reaction activity parameters in this area are extracted. The present invention realizes in-situ quantitative characterization of electrode surface reaction dynamics through optical-electrical signal fusion analysis technology. The detection device includes a high-precision prism coupler and a polarization light path system, wherein a linearly polarized light source is projected onto the prism-electrolyte sensing interface at an incident angle greater than the critical angle, and a detection model is established using the phase difference generated when p-polarized light and s-polarized light are reflected at the interface. This method precisely adjusts the operating parameters of the optical sensing system to operate in a high-sensitivity range, enabling real-time capture of subtle changes in the electrolyte's refractive index during electrochemical reactions on the electrode surface. Combined with the current signal synchronously output by the electrochemical workstation, an optical-electrical coupling analysis model is established to ultimately determine the electrode's reactivity distribution and extract the electrode surface redox activity parameters.

[0029] In one embodiment, the redox reaction of the electrode to be tested in a three-electrode system during the cyclic voltammetry process is used as an example to obtain the electrode reaction activity distribution and extract the activity parameters of each part. When the working electrode undergoes a redox reaction, the valence conversion of the active ions in the electrolyte triggers a change in the concentration gradient of the interface layer, which is converted into an optical phase signal through the refractive index modulation effect. For example, a parallel light beam is used, and horizontal and vertical polarizers and a wave plate for adjusting the phase are added to the incident module and the sensing module to form a dual-polarization phase difference field at the prism-coupled sensing interface.

[0030] In existing studies, under the condition of realizing weak value amplification (WVA), the relationship between light intensity and phase difference can be expressed as:

[0031]

[0032] Where I is the relative light intensity (LI), τ is the coupling strength, w0 is the optical frequency, is the phase difference, ε<<1 can make the post-selected state almost orthogonal to the pre-selected state, and τΔ<<1 is more likely to achieve weak coupling, satisfying the conditions of weak value amplification (WVA).

[0033] After analysis, the light intensity data obtained by the phase-weak measurement imaging system and the current density satisfy the following relationship:

[0034]

[0035] Where i(t) is the current density, deconvolution is the deconvolution calculation, n is the number of electrons in the redox reaction, F is the Faraday constant, b is a physical quantity related to the diffusion coefficients of the reduced and oxidized species and the sensitivity of the optical sensing system, ΔI(t) is the change in light intensity, π is the circumference of the circle, and t is time. In this way, a theoretical method for measuring the current density of electrode electrochemical reactions using a weak measurement imaging system was established.

[0036] The present invention is based on a prism-coupled total reflection optical system. By adding front and rear polarizers, an optical rotator, and an achromatic quarter-wave plate, the light intensity value is amplified. The prism in the system is directly coupled to the electrode to be tested to achieve in-situ detection of the active area of the electrode. Cyclic voltammetry is performed on the electrode with the aid of an electrochemical workstation to obtain a cyclic voltammetry curve, the ordinate of which represents the current of the entire electrode. At the same time, the change in the valence state of the active substance in the electrolyte on the electrode causes a change in the refractive index, which is reflected in the change in the image light intensity. The current density can be obtained by the relationship between the light intensity change and the current density between the pictures obtained by the camera. In this way, the overall current obtained by the electrochemical workstation is divided by the current density obtained by the optical sensor to obtain the reaction activity distribution of the electrode, and the redox activity parameters of the electrode surface are extracted.

[0037] Specifically, the provided weak measurement imaging detection method for rapid screening of working electrodes of flow batteries implements in-situ detection of the distribution of the reaction activity of flow battery electrodes participating in electrochemical reactions and quantitative acquisition of data according to the following steps:

[0038] Step S1: prepare two working electrodes, randomly select areas, and then cut out a large number of sizes suitable for the electrochemical workstation and weak measurement imaging system, and then perform electrochemical testing;

[0039] Step S2: Select one of each of the two working electrodes for testing, place the electrode to be tested as the working electrode into a three-electrode system module and immerse it in electrolyte so that it is in close contact with the prism, and then assemble the module into the sensor optical path;

[0040] Step S3, adjusting the reflective phase optical sensor to a total reflection state, and making the optical system state within the dynamic range with the highest sensitivity, while recording the initial optical signal of the sensor;

[0041] Step S4, add front and rear polarizers, the angle of the first polarizer with the vertical direction is π / 4, and then add a rotator and a λ / 4 achromatic wave plate to provide the necessary stable initial phase difference between horizontal polarization and vertical polarization. The rear polarization is nearly orthogonal to the front polarization to achieve weak measurement.

[0042] Step S5, synchronously perform electrochemical and optical detection: apply cyclic voltammetry scanning to the working electrode through the electrochemical workstation to obtain the voltammetric characteristic curve and extract the redox characteristic peak current; use the phase-type optical sensing system to collect the dynamic signal of the reflected light in real time and fit the relative current density change curve.

[0043] Step S6, determining the relationship between the current density obtained by the electrochemical workstation and the relative current density obtained by the weak measurement imaging system by performing cyclic voltammetry tests on the graphite plate electrode at different potential scan rates.

[0044] Step S7, obtaining the absolute value of the current density collected by the optical sensor during the cyclic voltammetry of the electrode to be tested based on the above relationship, so as to obtain the oxidation or reduction peak current density with physical units.

[0045] In step S8, the oxidation or reduction peak current of the electrode to be tested obtained by the electrochemical workstation is divided by the optical sensor to obtain the corresponding oxidation or reduction peak current density in physical units, so as to obtain the reaction activity distribution of the electrode to be tested and extract the electrode surface redox activity parameters.

[0046] In step S9, the obtained electrochemical reaction activity parameters are statistically fitted and compared with the redox peak current obtained by the workstation. The closer the slope is to 1, the better the performance of the working electrode is, and the larger the R2 is, the more uniform the distribution is, so as to judge the quality of the electrode.

[0047] Figure 1 This is a main implementation flow chart of the present invention, which specifically includes the following steps:

[0048] Step S110 , performing a cyclic voltammetry scan test on the electrode material using an electrochemical workstation to obtain an electrochemical reaction oxidation or reduction peak current.

[0049] The electrode to be tested was used as the working electrode in the three-electrode system, while the counter electrode was a graphite rod and the reference electrode was a saturated calomel electrode. Based on the three-electrode system, the electrolyte (0.1 M VO 2+ The working electrode of 2MH2SO4 was scanned at a voltage window of 0.55 V to 1.15 V at a scan rate of 1 mV s -1 Perform a cyclic voltammetry test to obtain a cyclic voltammetry curve, and then obtain the oxidation or reduction peak current.

[0050] Step S120: Using a camera to collect information on changes in light intensity at the electrode, and calculating the relative current density based on a quantitative relationship.

[0051] During the cyclic voltammetry process, a camera is used to collect information about changes in light intensity, thereby obtaining real-time changes in the refractive index of the electrolyte. The corresponding cyclic voltammetry curve is obtained based on the quantitative relationship between refractive index and current density. In this case, the relative current density is obtained.

[0052] Step S130 , performing linear sweep voltammetry tests on the uniform graphite plate electrode at different scan rates to achieve calibration of relative current density and actual current density.

[0053] By performing a linear sweep voltammetry test on a uniformly adjustable graphite plate electrode at different potential scan rates, the resulting current is divided by the reaction area to obtain the electrochemical current density. Simultaneously, the optical sensor can also obtain a linear sweep voltammetry curve, which can be used to obtain the relative current density at different potential scan rates. This allows the current density obtained by the electrochemical workstation and the relative current density obtained by the optical sensor to be combined to obtain a relationship between the two. Therefore, this calibration experiment involves the optical sensor obtaining a current density in physical units (step S140).

[0054] Step S150 , converting the light intensity information obtained by the electrochemical workstation into current information, obtaining the reaction activity distribution, and extracting the electrode surface redox activity parameters.

[0055] For the electrode under test, the relationship obtained from the calibration experiment is used to calculate the current density in physical units, thereby determining the peak oxidation or reduction current density. Finally, the peak current obtained by the electrochemical workstation is divided by the peak current density obtained by the optical sensor to obtain the active area of the electrode material participating in the electrochemical reaction, thereby determining the electrode reactivity distribution and extracting the electrode surface redox activity parameters.

[0056] Step S160: perform linear fitting with the oxidation peak current density as the horizontal axis and the absolute value of the reduction peak current density as the vertical axis. 2 This achieves the goal of quickly screening excellent working electrodes for flow batteries.

[0057] Specifically, the redox peak current density obtained by the electrochemical workstation was linearly fitted with the oxidation peak current density as the horizontal axis and the absolute value of the reduction peak current density as the vertical axis. By comparing the slope and R 2 This achieves the goal of quickly screening excellent working electrodes for flow batteries.

[0058] Figure 2 This is an example of using a weak measurement imaging system and a three-electrode system to obtain the electrode reaction activity distribution and extract the redox activity parameters of the electrode surface. Figure 2As shown, the characterization system mainly includes an incident light module 1, an optical sensing module 2, an imaging module 3 and a three-electrode system module 4. For example, the incident light module 1 is an LED light source with a wavelength of 633nm. The optical sensing module 2 is a high-refractive-index equilateral prism, one of whose interfaces is in contact with the electrode to be measured. The refractive index change of the electrolyte at the sensing interface in contact with the electrode to be measured (such as graphite felt, etc.) is measured by obtaining the phase change of the reflected light after the high-refractive-index prism. The reflected light passes through the rear polarizer to reach the CMOS camera, and then the computer 34 connected to the camera deconvolutes the light intensity data to obtain the current density. The three-electrode system module 4 mainly performs cyclic voltammetry tests on the electrode to be measured that is immersed in the electrolyte through an electrochemical workstation, and studies the redox reaction of the electrolyte at the electrode during the cyclic voltammetry process, which causes the refractive index to change. The current density of the electrode at that location can be obtained by calculation.

[0059] Figure 3 This system uses a weak-state imaging system to in situ detect the distribution of electrochemical reaction activity during cyclic voltammetry (CV), and to extract redox activity parameters from the electrode surface. Specifically, in the incident light module 1, light emitted by an LED light source 11 is guided by an optical fiber, passes through a collimating lens 12 and a front polarizer 13, and forms 45° linearly polarized light. It then passes through an optical rotator 14 and an achromatic quarter-wave plate 15 to obtain the necessary phase difference between horizontal and vertical polarization. The light then enters the optical sensor module 2 (a prism with a refractive index of 1.75) at an angle greater than total internal reflection. After total internal reflection at the interface between the prism 16 and the electrode to be measured 21, the light is transmitted through a rear polarizer 17 to a CMOS camera 18. The presence of the optical rotator 14 and the achromatic quarter-wave plate 15 ensures the system maintains its highest dynamic range of sensitivity, with the rear polarizer 17 and the front polarizer 13 in a nearly orthogonal state. For the three-electrode system, a titanium wire 22 is inserted into the electrode to be measured 21 as the working electrode, a graphite rod 23 serves as the counter electrode, and a saturated calomel electrode 24 serves as the reference electrode. The container 25 contains an electrolyte (0.1M VO 2+ and 2M H₂SO₄) to penetrate the electrode under test 21. The electrochemical workstation 26 drives the three-electrode system to perform an electrochemical reaction. The change in the electrolyte valence causes a change in its refractive index, which in turn affects the phase of the polarized light. Computer 31 displays the cyclic voltammetry curve generated by the electrochemical workstation. At this point, the CMOS camera 18 receives the change in light intensity caused by the change in the electrolyte's refractive index. Assuming nF / b = 1, the relative current density can be calculated by deconvolution. To obtain the absolute value of the current density, which is a physical quantity, a calibration experiment is required.

[0060] Figure 4 The results of the calibration experiment are shown in Figure 2. -1 , 2mV s -1, 3mV s -1 and 4mV s -1 ) to conduct linear sweep voltammetry test. Figure 4 As shown in (a), the surface of the uniformly adjustable electrode in contact with the prism is provided with non-stick tape, serving as the only reaction interface with a known area. The other surfaces are all covered with tape and cannot participate in the electrochemical reaction. The current obtained by the electrochemical workstation is divided by the known area to obtain the current density at different potential scan rates, as shown in Figure 1. Figure 4 (b). At the same time, Figure 4 (c) The relative current density obtained by the optical sensor is given. The oxidation peak currents of the two systems at different potential scan rates are obtained, i.e. pa(EW) and i pa(WM) , and drawn on Figure 4 (d) A linear relationship is given between the current density obtained by the electrochemical workstation and the relative current density obtained by the optical sensor by means of linear fitting. Thus, this calibration experiment enables the optical sensor to obtain a current density with physical units.

[0061] Figure 5 It is a schematic diagram of the process in which the weak measurement imaging system participates in the electrochemical reaction activity of the electrode material during the cyclic voltammetry process to obtain the reaction activity distribution of the electrode and extract the redox activity parameters of the electrode surface. Figure 5 (a) shows the electrode cyclic voltammetry curve obtained by the electrochemical workstation. Taking graphite felt as an electrode as an example, a 10×10 mm piece of graphite felt is attached to the prism surface. The electrochemical workstation obtains the current value, and its oxidation peak current is taken as I pa At the same time, the fitting CV graph obtained by randomly selecting a point for deconvolution operation through the weak measurement imaging system is 10×10mm=1cm -2 , so the peak current density is obtained by dividing the oxidation peak current by the corresponding area, such as Figure 5 (b) shown. Figure 5 (c) and Figure 5 (d) is the specific value of the redox peak current density of each part of the graphite felt electrode surface obtained by deconvolution calculation with the help of the linear relationship of the calibration experiment. The weak measurement imaging system is a reflective optical sensing structure (the penetration depth of the evanescent wave is several hundred nanometers). The current density obtained is in physical units, and the oxidation peak current density is taken as i pa , which provides a method for obtaining the reactivity distribution of electrochemical reactions.

[0062] Figure 6 This is a schematic diagram of the fitting of the redox peak current data obtained by two graphite felt electrodes in the electrochemical workstation and weak measurement imaging system. Figure 6(a) is the data obtained by graphite felt (GF) in the electrochemical workstation, the horizontal axis is the oxidation peak current density, and the vertical axis is the absolute value of the reduction peak current. Figure 6 (b) is the redox peak current density obtained by the graphite felt weak measurement imaging system, the horizontal axis is the oxidation peak current density, and the vertical axis is the absolute value of the reduction peak current. Figure 6 (c) and Figure 6 (d) is the redox peak current density of thermally activated graphite felt (TGF) obtained in the electrochemical workstation and weak measurement imaging system, and the graph is plotted as above. It is found that the data fitting effects obtained by different electrodes in different systems are similar, and the slope and R 2 The slopes and R of the fitting of different electrodes are consistent. 2 Due to its inherent properties, TGF performs better than GF, and correspondingly, the data obtained by the electrochemical workstation and weak measurement imaging system follow this pattern. Therefore, the weak measurement imaging system can eliminate a large amount of repetitive work and is a technical tool for characterizing electrode activity in electrochemical reactions and efficiently screening working electrodes for flow batteries.

[0063] In summary, in order to realize the detection of electrode material performance characterization, the present invention designs a weak measurement imaging detection method and device for simply and efficiently screening excellent working electrodes of liquid flow batteries. Generally speaking, it includes a weak measurement imaging system for real-time detection of electrode surface imaging and electrolyte refractive index, and obtains the distribution of electrode surface activity parameters through deconvolution operation, and performs statistical fitting on the obtained parameters to judge the performance of the working electrode, thereby achieving the effect of rapid screening. The present invention utilizes a weak measurement imaging system detection device combined with a potential scanning system to perform in-situ detection of electrode surface activity, which is not only simple to operate, but also can obtain in-situ, real-time, and effective electrode activity distribution, and obtain a large amount of activity parameter data. By detecting a single electrode instead of a batch of electrodes, a detection tool is provided for electrode modification and screening.

[0064] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A method for rapid screening of weak measurement imaging detection of working electrodes of flow batteries, comprising the following steps: Apply a cyclic voltammetry scanning signal to the electrochemical workstation to drive the working electrode to undergo redox reaction; During the redox reaction of the working electrode, the characteristic light intensity signal generated by the dynamic change of the refractive index of the electrolyte is captured in real time by a weak measurement imaging system and converted into current density distribution data. At the same time, the response current value output by the electrochemical workstation is synchronously collected to construct a function model of the ratio of current density to integral current. The effective active area of the working electrode is then obtained through algorithmic iterative optimization calculation, and all reaction activity parameters in the effective active area are extracted.

2. The method according to claim 1, characterized in that During the application of cyclic voltammetry scanning signals in the electrochemical workstation, a parallel light beam is used, and horizontal and vertical polarizers and a wave plate for adjusting the phase are added to the incident module and the sensing module to form a dual-polarization phase difference field at the prism coupling sensing interface.

3. The method according to claim 1, characterized in that The current density distribution data is obtained according to the following steps: Performing a cyclic voltammetry scan on the working electrode using the electrochemical workstation to obtain a cyclic voltammetry curve, wherein the vertical axis represents the overall current of the working electrode, and the change in the valence state of the active substance in the electrolyte on the working electrode causes a change in the refractive index, which is reflected in the change in the light intensity signal detected by the camera in the weak measurement imaging system; The current density is obtained by using the relationship between the change in the light intensity signal and the current density.

4. The method according to claim 3, characterized in that By deconvolution operation, the weak measurement imaging system can realize non-invasive detection of the current density distribution on the surface of the working electrode to be measured by using the change of the light intensity signal and the known redox reaction electron transfer number, Faraday constant, light intensity change correlation parameter and time correlation function.

5. A weak measurement imaging detection device for rapid screening of working electrodes of a flow battery, comprising an electrochemical workstation and a weak measurement imaging detection system, wherein: The electrochemical workstation is used to apply a cyclic voltammetry scanning signal to drive the working electrode to be tested to undergo an oxidation-reduction reaction; The weak measurement imaging detection system is used to capture the characteristic light intensity signal generated by the dynamic change of the refractive index of the electrolyte in real time during the redox reaction of the working electrode, convert the characteristic light intensity signal into current density distribution data, and simultaneously collect the response current value output by the electrochemical workstation, construct a ratio function model of current density and integrated current, and then obtain the effective active area of the working electrode through algorithm iterative optimization calculation, and extract all reaction activity parameters in the effective active area.

6. The device according to claim 5, characterized in that The weak measurement imaging system includes an incident light module, an optical sensing module and an imaging module, wherein the incident light module is a light source with a set wavelength, and the optical sensing module is a prism with a certain refractive index, and one interface of the prism is in contact with the working electrode.

7. The device according to claim 5, characterized in that In the total reflection optical path system of the weak measurement imaging system, front and rear polarizers, optical rotator and achromatic quarter wave plate are provided to realize light intensity value amplification.

8. The device according to claim 6, characterized in that The weak measurement imaging system is a reflective optical sensing structure, which is used to obtain a current density with a physical unit, and take its oxidation peak current density to obtain the reaction activity distribution of the electrochemical reaction.

9. The device according to claim 8, characterized in that The current density in physical units is calibrated by using linear fitting to give a linear relationship between the current density obtained by the electrochemical workstation and the relative current density obtained by the optical sensor module of the weak measurement imaging system.

10. A computer-readable storage medium having a computer program stored thereon, wherein: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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