Real-time detection method for magnetic resonance imaging ion concentration of aqueous ion battery

Abstract

The invention discloses a magnetic resonance imaging ion concentration real-time detection method for an aqueous ion battery. The method comprises the following steps: SO, assembling the aqueous ion battery; the method comprises the following steps: S1, putting an aqueous ion battery into a detection area of a magnetic resonance imager, and connecting an electrochemical workstation; s2, determining an area where an electrode-electrolyte interface is located through a magnetic resonance imager; and S3, electrifying, and acquiring two-dimensional image data of a collector-electrolyte interface at equal intervals to obtain a characterization map of the ion concentration of the electrolyte. The method is suitable for the magnetic resonance imager to detect the battery in an in-situ experiment, the ion concentration information of the aqueous ion battery-electrode interface can be obtained, so that deposition and stripping of electrode interface metal are analyzed, the control sensitivity is high, the detection result is stable and reliable, and the method has the possibility of wide popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of battery characterization, and in particular relates to a real-time detection method for ion concentration of an aqueous ion battery by magnetic resonance imaging, which is applicable to a magnetic resonance imaging instrument. Background Art

[0002] Aqueous ion batteries, such as aqueous zinc batteries, have the advantages of low cost, high safety, high storage and high energy density, and have become a hot topic in the battery field in recent years. However, the severe dendrite growth at the interface of zinc batteries has seriously inhibited its commercialization process. The detection of spatial ion transfer information and interface reaction conditions in aqueous zinc batteries in situ is of great significance for the evaluation and improvement of the performance of aqueous zinc batteries.

[0003] At present, there are certain limitations in the in-situ characterization technology for aqueous ion batteries. For example, optical microscopes require the battery model to be light-transmissive; in-situ differential electrochemical mass spectrometry can only indirectly reflect the electrochemical reaction process through the gas consumption and generation during the battery operation. Similar characterization technologies cannot conveniently and intuitively reflect the electrochemical process and spatial information during battery operation. Based on the advantages of magnetic resonance imaging technology such as non-destructive, non-invasive and real-time, the aqueous zinc battery characterization technology based on magnetic resonance imaging can collect multi-directional, multi-level and multi-dimensional ion concentration information, and can track and analyze its electrochemical reactions in real time. Therefore, it is of great significance to develop aqueous ion batteries and real-time detection methods for ion concentrations suitable for magnetic resonance imaging. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a real-time detection method for ion concentration of aqueous ion batteries using magnetic resonance imaging. By combining an easily assembled battery model with a magnetic resonance imaging device, the ion concentration can be effectively measured and characterized, thus solving the problems in the above-mentioned background technology.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a real-time detection method of ion concentration of an aqueous ion battery by magnetic resonance imaging, comprising the following steps:

[0006] SO, assembled aqueous ion battery;

[0007] S1, placing the aqueous ion battery into the detection area of ​​the magnetic resonance imaging apparatus and connecting it to the electrochemical workstation;

[0008] S2, determine the region where the electrode-electrolyte interface is located through the scout sequence;

[0009] S3, turn on the power, use the FSE sequence to collect two-dimensional image data of the electrode-electrolyte interface at equal intervals to obtain a characterization spectrum of the electrolyte ion concentration.

[0010] Preferably, in step S1, the electrochemical workstation is set to a constant current charging and constant current discharging mode.

[0011] Preferably, in step S2, a two-dimensional coronal image of the aqueous ion battery is collected to find the interface where the metal anode is located; a layer thickness of 0.5 mm to 1 mm is selected, and the two-dimensional cross-section of the area is the area where the electrode-electrolyte interface is located.

[0012] Preferably, in step S2, the scout sequence of the Vnmrj software is first used to locate and sample the aqueous ion battery, and the spatial position of the battery is adjusted to the center of the acquired image; then tuning is performed to keep the frequency point consistent with the nuclear magnetic resonance frequency of the hydrogen nucleus; then the ge3dshim sequence is used to perform high-order shimming on the area where the aqueous ion battery is located; finally, the prescan list is used for power correction.

[0013] Preferably, in step S3, the fse sequence is used to set acquisition parameters, and the parameters include charging time, current size, sampling sequence, sampling area, and sampling time.

[0014] Preferably, in step S3, first a two-dimensional magnetic resonance image of the electrode-electrolyte interface is acquired when no power is supplied; then the LANBTS control software is opened, power is supplied, and the first in-situ two-dimensional magnetic resonance image acquisition is performed simultaneously; thereafter, two-dimensional magnetic resonance images of the electrode-electrolyte interface are acquired at equal intervals.

[0015] Preferably, in step S3, the acquired two-dimensional magnetic resonance image is processed by Matlab, and a colorbar is added to the acquired two-dimensional magnetic resonance image to obtain an ion concentration imaging diagram at the electrode-electrolyte interface.

[0016] Preferably, the aqueous ion battery comprises a battery cavity, a positive electrode sheet, a negative electrode sheet, a first current collector, a second current collector, a first O-ring, a second O-ring, a first threaded cap, a second threaded cap, a first copper wire, and a second copper wire; a first current collector fixing groove is provided in the first threaded cap, and a second current collector fixing groove is provided in the second threaded cap; a first electrode fixing platform and a second electrode fixing platform are provided on both sides of the battery cavity; the first current collector is fixed on the groove of the first threaded cap, the first copper wire is welded to the groove of the first current collector, and passes through the round hole in the first threaded cap; the second current collector is fixed on the groove of the second threaded cap, the second copper wire is welded to the groove of the second current collector, and passes through the round hole in the second threaded cap; the positive electrode sheet is fixed to the first electrode fixing platform in the battery cavity, the negative electrode sheet is fixed to the second electrode fixing platform in the battery cavity, and the closed cavity formed between the two electrode sheets and the battery cavity is filled with electrolyte; after the first threaded cap and the second threaded cap are screwed into the battery cavity, the first current collector contacts the positive electrode sheet, and the second current collector contacts the negative electrode sheet.

[0017] Preferably, the aqueous ion battery comprises an aqueous zinc battery, and the positive electrode sheet and the negative electrode sheet are zinc sheets.

[0018] Preferably, the first O-ring is installed in a first threaded cap; and the second O-ring is installed in a second threaded cap.

[0019] Compared with the background technology, this technical solution has the following advantages:

[0020] 1. The present invention adopts the combination of electrochemical and magnetic resonance technologies, and utilizes the advantages of nuclear magnetic resonance imaging such as non-destructive, non-invasive and real-time, so as to track and analyze its electrochemical reaction in real time, and combine it with the metal deposition and peeling at the electrode sheet to achieve multi-directional, multi-level and multi-dimensional characterization of concentration information; at the same time, the detection method is universal, has a wide range of applications and is highly reproducible.

[0021] 2. The present invention uses the scout sequence and the fse sequence to quickly determine the area where the electrode-electrolyte interface is located, and selects a specific layer thickness of 0.5mm-1mm, which can ensure the signal-to-noise ratio of the collected image while reducing the characterization time.

[0022] 3. The ion concentration information detected by the present invention is based on the ions themselves, rather than the entire electrolyte.

[0023] 4. The battery of the present invention improves the sealing of the original battery model based on the airtightness of the thread and the O-ring, thereby solving the problem that the collected image is obviously not full enough; at the same time, the battery model is easy to assemble and has strong stability. The material is made of polytetrafluoroethylene, which is practical and stable, and can ensure the uniformity and stability of the magnetic field of the main magnetic field in the magnetic resonance imager and the coil radio frequency field during the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of aqueous ion battery;

[0025] Figure 2 is a flow chart of the detection method;

[0026] Figure 3 This is the structural assembly diagram of the aqueous ion battery;

[0027] Figure 4 A schematic diagram of the connection relationship between a magnetic resonance imaging device, an electrochemical workstation and a battery;

[0028] Figure 5 The constant current charge and discharge curve of the battery in the embodiment changes with time;

[0029] Figure 6 This is a two-dimensional cross-sectional image of the electrode-electrolyte interface collected when power is applied in the embodiment, and the value on the right represents the zinc ion strength information.

[0030] Among them, 1-battery cavity; 2-positive electrode sheet; 3-negative electrode sheet; 4-first current collector; 5-second current collector; 6-first O-ring; 7-second O-ring; 8-first threaded cap; 9-second threaded cap; 10-first copper wire; 11-second copper wire; 12-electrochemical workstation; 13-magnetic resonance imager. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. The terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0032] Example

[0033] This embodiment assembled an aqueous zinc battery and performed real-time detection of ion concentration by 7.0T magnetic resonance imaging, which specifically included the following steps:

[0034] SO, assembled aqueous ion battery;

[0035] Please refer to Figure 1The present embodiment is applicable to an aqueous zinc battery for a 7.0T magnetic resonance imager, comprising: a battery cavity 1, a positive electrode sheet 2, a negative electrode sheet 3, a first current collector 4, a second current collector 5, a first O-type sealing ring 6, a second O-type sealing ring 7, a first threaded cap 8, a second threaded cap 9, a first copper wire 10, and a second copper wire 11; the first threaded cap 8 has a first current collector fixing groove, and the second threaded cap 9 has a second current collector fixing groove; the battery cavity has a first electrode fixing platform and a second electrode fixing platform on both sides; the first current collector 4 is fixed on the groove of the first threaded cap, and the first copper wire 10 and the first current collector are fixed on the first threaded cap. The second current collector 5 is fixed on the groove of the second threaded cap, and the second copper wire 11 is welded to the groove of the second current collector and passes through the round hole in the second threaded cap; the positive electrode sheet 2 is fixed to the first electrode fixing platform in the battery cavity, and the negative electrode sheet 3 is fixed to the second electrode fixing platform in the battery cavity, and the closed cavity formed between the two electrode sheets and the battery cavity is filled with electrolyte; after the first threaded cap 8 and the second threaded cap 9 are screwed into the battery cavity 1, the first current collector 4 is in contact with the positive electrode sheet 2, and the second current collector 5 is in contact with the negative electrode sheet 3.

[0036] The first O-ring 6 is installed in the first threaded cap; the second O-ring 7 is installed in the second threaded cap. The first O-ring 6 and the second O-ring 7 can be one or more of silicone, nitrile rubber or ethylene propylene rubber. In this embodiment, the first O-ring 6 and the second O-ring 7 have a diameter of 18 mm and are sleeved at the root of the threaded cap, which can well ensure the sealing of the battery and solve the problem that the image collected by the original model is obviously not full enough.

[0037] The first threaded cap 8, the second threaded cap 9, the first current collector fixing groove, the second current collector fixing groove, the battery cavity 1, the first electrode fixing platform and the second electrode fixing platform are all made of polytetrafluoroethylene material, which can effectively reduce the distortion effect of the radio frequency field. Among them, the first threaded cap 8 and the second threaded cap 9 have an outer diameter of 20mm and an inner diameter of 16mm, and there is a circular fine hole with a diameter of 1mm in the middle for the first copper wire 10 and the second copper wire 11 to pass through.

[0038] The first current collector 4 and the second current collector 5 are both circular copper sheets with a diameter of 14 mm and a thickness of 1 mm, and a conical groove is provided in the center of the copper sheet to facilitate solder attachment and ensure a flat surface after soldering, which is convenient for installation and ensures the airtightness of the battery.

[0039] The battery cavity 1 has a diameter of 20mm and an outer length of 35mm, with 10mm internal threads at both ends, and the electrolyte loading area is 10mm in diameter and 15mm in length. The positive electrode sheet 2 and the negative electrode sheet 3 are both zinc sheets with a diameter of 15.6mm and a thickness of 1mm. The diameters of the first electrode fixing platform and the second electrode fixing platform are both 15.6mm. After the electrode sheets are installed, they can just wrap the electrolyte to ensure airtightness.

[0040] During assembly, the first current collector and the second current collector of the aqueous zinc-zinc battery are both copper sheets, and there are non-penetrating conical grooves in the center of the copper sheets to facilitate welding with the first copper wire and the second copper wire. After the first copper wire and the first current collector are welded by spot tin welding, the first copper wire passes through the through circular hole in the center of the first threaded cap, and the first current collector is pressed into the first current collector fixing groove located in the first threaded cap, and the first O-type sealing ring is inserted into the groove at the root of the thread of the first threaded cap, and then 1:1 AB glue is applied to the outer joint of the first threaded cap and the first copper wire, and the colloid is waited for to solidify; the second copper wire, the second current collector and the second O-type sealing ring are assembled in the same way.

[0041] Both the positive electrode sheet and the negative electrode sheet are zinc sheets, and the electrolyte is a zinc sulfate heptahydrate solution with a concentration of 1 mol / L. First, use tweezers to put the first zinc sheet into the battery cavity, then screw the assembled first threaded cap into the battery cavity until the first O-ring at the root of the thread is squeezed, then invert the entire battery cavity, use a pipette to fill the battery cavity with electrolyte, ensure that the electrolyte fills the battery cavity, then put in the second zinc sheet, and finally screw the assembled second threaded cap into the battery cavity until the second O-ring at the root of the thread is squeezed.

[0042] S1, placing the aqueous ion battery into the detection area of ​​the magnetic resonance imaging apparatus and connecting it to the electrochemical workstation;

[0043] Connect the assembled aqueous zinc-zinc symmetrical battery to the electrochemical workstation LANBTS to ensure that its static voltage is below 1mA. Then connect the first copper wire and the second copper wire of the aqueous zinc-zinc symmetrical battery to the two external copper wires through double-sided conductive copper tape, and connect the two external copper wires to the electrochemical workstation LANBTS. Set the charging mode to constant current charging, the time is 1 hour, the current size is 1mA, and the discharge mode is constant current discharge, the time is 1 hour, and the current size is 1mA.

[0044] S2, determine the region where the electrode-electrolyte interface is located through the scout sequence;

[0045] Open the Vnmrj software that controls the 7.0T magnetic resonance imager on the computer, insert the assembled battery, use the scout sequence to locate and sample the battery multiple times, and adjust the battery's spatial position to the center of the acquired image. Then tune to ensure that the frequency point is consistent with the nuclear magnetic resonance frequency of the hydrogen nucleus to ensure the clarity and signal-to-noise ratio of the acquired image. Then use the ge3dsh im sequence to perform high-order uniform field on the area where the battery is located. Finally, use prescan List for power correction. Refer to the battery coronal image acquired by the scout sequence to find the junction between the electrolyte and the electrode sheet, and select a slice thickness of 1 mm as the area where the electrode-electrolyte interface is located.

[0046] S3, turn on the power, use the fse sequence to collect images, and obtain the characterization spectrum of the electrolyte ion concentration by collecting the changes in the intensity values ​​of the images.

[0047] Use the fse sequence and set the acquisition parameters, TR is 5000ms, TE is the minimum value (3-5ms), the pixel point is 96*96, avoid long acquisition time, FOV is set to 40*40mm2, the slice thickness is 1mm, the inversion recovery step is 10-1500ms, the number of single acquisition images is 6, and the single acquisition time is 6 minutes and 10 seconds. First, a two-dimensional magnetic resonance image is acquired when it is not powered on, then the LANBTS control software is opened, the power is turned on, and the first in-situ two-dimensional magnetic resonance image is acquired at the same time. The electrochemical curves during charging and discharging are shown in the figure. Figure 5 shown.

[0048] The two-dimensional magnetic resonance images collected by the magnetic resonance imaging device are processed by Matlab. The purpose is to add a colorbar to the collected magnetic resonance images so that the intensity value of each area on the image can be seen clearly. Figure 6 An image of the zinc ion concentration at the electrode-electrolyte interface is shown.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for real-time detection of ion concentration of an aqueous ion battery using magnetic resonance imaging, characterized in that: The steps include: SO, assembled aqueous ion battery; S1, placing the aqueous ion battery into the detection area of ​​the magnetic resonance imaging apparatus and connecting it to the electrochemical workstation; S2, determine the region where the electrode-electrolyte interface is located by magnetic resonance imaging; S3, power on, collect two-dimensional image data of the electrode-electrolyte interface at equal intervals to obtain a characterization spectrum of the electrolyte ion concentration.

2. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 1, characterized in that: In step S1, the electrochemical workstation is set to a constant current charging and constant current discharging mode.

3. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 1, characterized in that: In step S2, a two-dimensional coronal image of the aqueous ion battery is collected to find the interface where the metal anode is located; a layer thickness of 0.5 mm to 1 mm is selected, and the two-dimensional cross-sectional electrode-electrolyte interface of the area is located.

4. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 3, characterized in that: In step S2, the aqueous ion battery is located and sampled by a magnetic resonance imaging device, and the spatial position of the battery is adjusted to the center of the acquired image; then tuning is performed to keep the frequency point consistent with the nuclear magnetic resonance frequency of the hydrogen nucleus; then high-order uniform field is performed on the area where the aqueous ion battery is located; and finally power correction is performed.

5. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 1, characterized in that: In step S3, the acquisition parameters are set, including charging time, current size, sampling sequence, sampling area, and sampling time.

6. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 1, characterized in that: In step S3, firstly, a two-dimensional magnetic resonance image of the electrode-electrolyte interface is acquired when no power is supplied; then, the electrochemical workstation control software is opened, the power is supplied, and the first in-situ two-dimensional magnetic resonance image is acquired simultaneously; thereafter, two-dimensional magnetic resonance images of the electrode-electrolyte interface are acquired at equal intervals.

7. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 1, characterized in that: In step S3, the acquired two-dimensional magnetic resonance image is processed to obtain an ion concentration imaging diagram at the electrode-electrolyte interface.

8. The method for real-time detection of ion concentration of an aqueous ion battery using magnetic resonance imaging according to claim 1, characterized in that: The aqueous ion battery comprises a battery cavity, a positive electrode sheet, a negative electrode sheet, a first current collector, a second current collector, a first O-ring, a second O-ring, a first threaded cap, a second threaded cap, a first copper wire, and a second copper wire; the first threaded cap has a first current collector fixing groove, and the second threaded cap has a second current collector fixing groove; the battery cavity has a first electrode fixing platform and a second electrode fixing platform on both sides; the first current collector is fixed on the groove of the first threaded cap, the first copper wire is welded to the groove of the first current collector, and passes through the round hole in the first threaded cap; the second current collector is fixed on the groove of the second threaded cap, the second copper wire is welded to the groove of the second current collector, and passes through the round hole in the second threaded cap; the positive electrode sheet is fixed to the first electrode fixing platform in the battery cavity, the negative electrode sheet is fixed to the second electrode fixing platform in the battery cavity, and the closed cavity formed between the two electrode sheets and the battery cavity is filled with electrolyte; after the first threaded cap and the second threaded cap are screwed into the battery cavity, the first current collector contacts the positive electrode sheet, and the second current collector contacts the negative electrode sheet.

9. The method for real-time detection of ion concentration of an aqueous ion battery by magnetic resonance imaging according to claim 8, characterized in that: The aqueous ion battery comprises an aqueous zinc battery, wherein the positive electrode sheet and the negative electrode sheet are zinc sheets.

10. The method for real-time detection of ion concentration of an aqueous ion battery using magnetic resonance imaging according to claim 8, characterized in that: The first O-type sealing ring is installed in the first threaded cap; the second O-type sealing ring is installed in the second threaded cap.

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