Miniature device for dynamically observing electrochemical reaction of solid-state alkali metal battery as well as preparation method and application of miniature device

Abstract

The invention discloses a miniature device for dynamically observing electrochemical reaction of a solid-state alkali metal battery and a preparation method and application thereof, and the preparation method comprises the steps: S1, wiping an electrode on the surface of a DENS thermoelectric chip, and attaching and solidifying the DENS thermoelectric chip which is wiped clean on a PCB substrate; s2, connecting an electrode of the DENS thermoelectric chip with a gold bonding pad on the PCB substrate by using a lead bonding process to form reliable electrical connection; s3, after connection of the DENS thermoelectric chip and the PCB substrate is completed, a copper circuit on the PCB substrate is connected with a copper wire through soldering tin, and overall conduction of the circuit is ensured; and S4, placing the micro battery at the electrode of the micro device for observing the electrochemical reaction of the solid alkali metal battery under the charging and discharging conditions. The miniature device has a multi-scale characterization function, a high-resolution surface topography image can be obtained in a scanning electron microscope (SEM), and meanwhile, a sample is further thinned, so that high-resolution fine characterization of the transmission electron microscope is carried out at the same position.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state battery characterization, and in particular to a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries using a scanning electron microscope, and a preparation method and application thereof. Background Art

[0002] With the rapid development of integrated circuits and micro-nano chip technologies, especially in the fields of smartphones, IoT devices, and high-performance computing, the demand for efficient and reliable energy support is increasing. Conventional lithium-ion batteries usually use liquid electrolytes, which are flammable and chemically unstable, and are prone to cause safety hazards such as fire and explosion. Micro solid-state alkali metal batteries significantly improve safety and reduce the risk of leakage and combustion due to the use of solid electrolytes. However, during the charging and discharging process, electrochemical reactions may still cause battery failure. For example, the formation of lithium or sodium dendrites may pierce the electrolyte and cause a short circuit; at the same time, the mechanical failure of the electrolyte may cause battery polarization, thereby affecting the overall performance. These failure mechanisms indicate that it is necessary to develop suitable micro devices and characterization methods to monitor the performance changes and failure processes of micro batteries, so as to achieve real-time evaluation and improve the design to improve the reliability and service life of the battery.

[0003] Based on this, the currently commonly used optical and X-ray microscopic characterization methods have low spatial resolution and cannot be effectively applied to local interface research. Electron microscopy technology can observe the microstructure and morphological changes of materials at nanoscale resolution and reveal their relationship with battery performance. Through energy spectrum analysis, this technology can also provide information on the elemental composition of materials and help identify the reaction mechanism of the electrode-electrolyte interface.

[0004] At present, some studies are mainly carried out by applying bias voltage, such as Yang Yong et al. (Chemomechanical Failure Mechanism Study in NASICON-Type Li 1.3 Al 0.3 Ti 1.7(PO4)3Solid-State Lithium Batteries) conducted a series of studies on the interface between LATP and lithium by in situ TEM observation, but the observation was of a local area and not under working conditions. Other studies mainly conducted real-time dynamic observations in a transmission electron microscope (TEM) after constructing a micro-nanoscale battery model. Through in situ TEM observation, details such as lattice distortion, defect formation, and phase change of LiCoO2 cathode materials during electrochemical delithiation can be seen. Although TEM can provide high-resolution images, it can only provide two-dimensional information and cannot fully reflect the three-dimensional structural changes of battery materials, which limits the understanding of some complex electrochemical processes. However, scanning electron microscopy (SEM) can generate high-resolution surface images, revealing the characteristics of electrode materials such as particle size, surface cracks, and sediments; FIB can prepare micron-level battery samples, which can be observed in detail in SEM, and their working conditions are closer to actual battery conditions. At the same time, cryo FIB-SEM is used to reduce the damage of the electron beam to the sample, thereby obtaining non-destructive three-dimensional morphological information. Nevertheless, it is still very challenging to realize the in-situ dynamic observation of the electrochemical reaction of micron-scale solid-state batteries in scanning electron microscopes, such as the preparation of micro batteries and the lack of suitable micro devices, so it is necessary to continuously develop and improve existing technologies and methods. Summary of the invention

[0005] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a micro device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery in a scanning electron microscope, and a preparation method and application thereof, thereby realizing the observation of the electrochemical reaction of a micro solid-state alkali metal battery in a scanning electron microscope.

[0006] The technical solution adopted by the present invention is:

[0007] A micro device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery, characterized in that it comprises a DENS thermoelectric chip and a PCB substrate, wherein the DENS thermoelectric chip and the PCB substrate are electrically connected; a gold pad and a copper circuit are arranged on one side of the PCB substrate, two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuit is connected to the copper wire solder to ensure the overall conduction of the circuit; a micro battery is arranged at the electrode of the DENS thermoelectric chip by using FIB.

[0008] Furthermore, the two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads on the PCB substrate through wire bonding, and the connection between the wire and the DENS thermoelectric chip adopts a wedge bonding method, and the connection with the PCB substrate adopts a ball bonding method.

[0009] A method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery, characterized in that the preparation method is carried out according to the following steps:

[0010] S1. Wipe the electrodes on the surface of the DENS thermoelectric chip clean, and then bond and solidify the cleaned DENS thermoelectric chip on the PCB substrate;

[0011] S2. Use wire bonding technology to connect the electrodes of the DENS thermoelectric chip to the gold pads on the PCB substrate to form a reliable electrical connection;

[0012] S3. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the copper circuit and the copper wire on the PCB substrate are connected by soldering to ensure the overall conduction of the circuit;

[0013] S4. Place the microbattery at the electrode of the microdevice to observe the electrochemical reactions of the solid-state alkali metal battery under charging and discharging conditions.

[0014] Furthermore, in step S1, two electrodes on the surface of the DENS thermoelectric chip are cleaned with anhydrous ethanol having a content of ≥99.7% to remove contaminants. During the wiping process, it is necessary to avoid touching the silicon nitride film window to avoid damaging the electrode. The DENS thermoelectric chip used has a 50nm thick silicon nitride film window.

[0015] Furthermore, in step S1, the DENS thermoelectric chip is bonded and cured at a predetermined position on the PCB substrate using insulating glue, and the horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5-1 mm, providing conditions for subsequent wire bonding.

[0016] Furthermore, a single-sided PCB substrate with a specification of 10*10*0.8 mm and having a gold pad and a copper circuit is selected. The diameter of the pad for the lead on the PCB substrate is 300 μm, and the diameter of the pad for connecting with the copper wire is 800 μm.

[0017] Further, in step S2, the wire bonding process is thermocompression bonding, ultrasonic bonding or thermocompression ultrasonic bonding.

[0018] Furthermore, the material used in the wire bonding process is a gold wire with a purity of 99.99%, the diameter of the gold wire is 20 μm, and the arc length is 5 mm;

[0019] The bonding temperature of the wire bonding process is 150°C and the bonding time is 50 to 100 milliseconds. After the bonding is completed, the appearance of the solder joint is observed through a microscope to preliminarily judge the bonding quality.

[0020] Furthermore, the specific operation process of bonding is as follows: move the capillary above the pad and align it with the center of the pad; lower the capillary so that the gold ball contacts the pad; apply ultrasonic energy, pressure and heat at the same time to complete the first bonding. After the bonding is completed, the capillary moves upward to pull the gold wire out to form an arc loop; control the height and shape of the loop to avoid the gold wire being too tight or too loose, and complete the second bonding in the same way.

[0021] Furthermore, in step S3, tin is used as solder, and the solder is heated with a soldering iron until it flows. When the solder flows to the gold pad with a diameter of 800 μm, the soldering iron is quickly removed to complete the overall conduction of the circuit.

[0022] Furthermore, the conductivity test uses Chenhua electrochemical workstation to determine the conductivity of the circuit by measuring the resistance value. During the test, each solder joint and connection point is checked one by one to ensure that there is no open circuit or short circuit problem.

[0023] Furthermore, in step S4, a micro-battery with a thickness of micrometer level is prepared using focused ion beam technology FIB, and its electrochemical reaction under charging and discharging conditions is observed.

[0024] An application of a micro-device, characterized in that the solid electrolyte and the micro-device are quickly transferred to a chamber of a scanning electron microscope for observation of electrochemical reactions, and then evacuated to a usable state;

[0025] Platinum with a thickness of 2 μm was deposited under an ion beam to connect to the electrode. The deposition voltage and current were 30 kV and 0.23 nA. According to the FIB extraction process of conventional samples, the length consistent with the DENS thermoelectric chip electrode was determined for extraction. The negative electrode material, electrolyte material, and positive electrode material were extracted one by one, transferred and fixed to the two electrodes, and then the platinum in the middle part of the electrolyte surface was milled to avoid short circuit of the micro battery.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The micro-device provided by the present invention has the ability to observe and monitor the electrochemical reactions of solid-state alkali metal batteries in real time and with high resolution. This is very valuable for improving the performance and life of the battery and for better understanding the dynamic changes of the internal processes of the battery, thereby improving the efficiency of battery research and application.

[0028] 2. The micro device provided by the present invention has the advantages of simple structure, low manufacturing cost, etc., and is easy to promote and apply. Its design and components are relatively few, making it easy to manufacture and operate, and reducing the number and complexity of parts.

[0029] 3. The micro-device provided by the present invention has a multi-scale characterization function, which can obtain high-resolution surface morphology images in a scanning electron microscope (SEM), and further thin the sample to perform high-resolution fine characterization of a transmission electron microscope (TEM) at the same location. This design realizes multi-scale observation of the same area and can more comprehensively analyze the microstructure and performance of the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A diagram of a micro device provided by the present invention.

[0031] Figure 2 It is the circuit conductivity test method and the corresponding iv curve diagram.

[0032] Figure 3 Schematic diagram of a micro battery.

[0033] Figure 4 A scanning electron microscope image of the electrochemical reaction occurring in a micro solid-state battery. DETAILED DESCRIPTION

[0034] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0036] The present invention will be described in detail below in conjunction with exemplary embodiments with reference to the accompanying drawings.

[0037] refer to Figure 1 A micro device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery of the present invention comprises a DENS thermoelectric chip and a PCB substrate, wherein the DENS thermoelectric chip and the PCB substrate are electrically connected; a gold pad and a copper circuit are arranged on one side of the PCB substrate, two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuit is connected to the copper wire solder to ensure the overall conduction of the circuit; a micro battery is arranged at the electrode of the DENS thermoelectric chip.

[0038] Specifically, the two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads on the PCB substrate through wire bonding. The wire is connected to the DENS thermoelectric chip by wedge bonding, and is connected to the PCB substrate by ball bonding.

[0039] The present invention provides a method for preparing a micro-device for dynamically observing electrochemical reactions of a solid-state alkali metal battery, wherein the preparation method is performed according to the following steps:

[0040] S1. Wipe the electrodes on the surface of the DENS thermoelectric chip clean, and then bond and solidify the cleaned DENS thermoelectric chip on the PCB substrate;

[0041] Specifically, dip the tip of the filter paper in anhydrous ethanol with a content of ≥99.7%, clean the two powered electrodes on the surface of the DENS thermoelectric chip to remove contaminants, and avoid touching the silicon nitride film window during the wiping process to avoid damaging the electrode;

[0042] Specifically, the DENS thermoelectric chip is bonded and cured at a predetermined position on the PCB substrate using insulating glue, and the horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5 mm, providing conditions for subsequent wire bonding.

[0043] S2. Use wire bonding technology to connect the electrodes of the DENS thermoelectric chip to the gold pads on the PCB substrate to form a reliable electrical connection;

[0044] Specifically, a single-sided PCB substrate with a specification of 10*10*0.8mm and a gold pad and a copper circuit is selected, the pad diameter for the lead on the PCB substrate is 300μm, and the pad diameter for connecting with the copper wire is 800μm;

[0045] The two electrodes on the DENS thermoelectric chip are connected to the gold pads on the PCB substrate by wire bonding. The wire bonding process is hot pressing and ultrasonic bonding. The connection with the DENS thermoelectric chip adopts wedge bonding, and the connection with the PCB substrate adopts spherical bonding. This bonding method can keep the surface of the DENS thermoelectric chip relatively flat, which is convenient for the later FIB sample preparation.

[0046] The specific operation of bonding is to move the capillary above the pad and align it with the center of the pad; lower the capillary so that the gold ball contacts the pad; and apply ultrasonic energy, pressure, and heat at the same time to complete the first bonding. After the bonding is completed, the capillary moves upward to pull the gold wire out to form an arc loop; control the height and shape of the loop to avoid the gold wire being too tight or too loose, and complete the second bonding in the same way.

[0047] The wire bonding material is a gold wire with a purity of 99.99%. The diameter of the gold wire is 20μm, the arc length is 5mm, the ultrasonic power is 210mV, the bonding pressure is 3.4N, the bonding temperature is 150℃, and the bonding time is 80 milliseconds. After the bonding is completed, the appearance of the solder joint can be observed under a microscope to preliminarily judge the bonding quality. Figure 1 )

[0048] S3. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the copper circuit and the copper wire on the PCB substrate are connected by soldering to ensure the overall conduction of the circuit;

[0049] Specifically, tin is used as solder, and a soldering iron is used to heat the solder until it flows. When the solder flows to a gold pad with a diameter of 800 μm, the soldering iron is quickly removed to complete the overall conduction of the circuit.

[0050] Continuity testing usually uses a dedicated test instrument to determine the continuity of the circuit by measuring the resistance value. During the test, each solder joint and connection point is checked one by one to ensure that there are no open circuits or short circuits.

[0051] S4. Use focused ion beam technology FIB to prepare micron-level thickness micro batteries and observe their electrochemical reactions under charging and discharging conditions.

[0052] Embodiment 1:

[0053] Continuity testing of micro devices

[0054] Wipe the surface electrodes of the DENS thermoelectric chip clean, fix the DENS thermoelectric chip on the substrate through patch and curing, and use the wire bonding process to connect the DENS thermoelectric chip electrodes to the pads on the PCB substrate to form a reliable electrical connection; after completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the micro device to the copper wire through soldering to ensure the overall conduction of the circuit.

[0055] When the circuit is open, the Chenhua electrochemical workstation is used to connect the two copper wires of the two devices to obtain a linear scanning voltammetric curve, where the initial potential is 0v, the end potential is 1v, the scanning speed is 0.005v / s, and the sampling interval is 0.001v. According to the relationship between the voltage and current values ​​obtained from the curve, the resistance of the circuit can be calculated to be 10 9 Order of magnitude, close to a circuit-breaking state.

[0056] The micro-device was fixed on a cylindrical sample stage with a 45° inclination angle, and the positive and negative electrodes of the micro-device were connected using ion beam deposited platinum (15*1*2μm) to put the circuit in a short-circuit state. The linear sweep voltammetric curve was tested using a Chenhua workstation under the same conditions, and the resistance of the circuit was 310Ω, which was basically consistent with the theoretical value, indicating that the device had good conductivity everywhere and there was no short circuit or open circuit. ( Figure 2 )

[0057] Embodiment 2:

[0058] FIB preparation of micro solid-state alkali metal batteries

[0059] Wipe the surface electrodes of the DENS thermoelectric chip clean, fix the DENS thermoelectric chip on the substrate through patch and curing, and use the wire bonding process to connect the DENS thermoelectric chip electrodes to the gold pads on the PCB substrate to form a reliable electrical connection; after completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the micro device to the copper wire through soldering to ensure the overall conduction of the circuit.

[0060] The solid electrolyte is selected according to actual needs. In the present invention, garnet LLZTO is selected, and the surface is polished with sandpaper with mesh numbers of 800, 2500, 2500, and 10000. The polishing time is 5min, 10min, 20min, and 30min, respectively, to remove the surface oxide layer and keep the surface flat. Then, it is quickly transferred to the chamber of the scanning electron microscope together with the micro-device and evacuated to a usable state.

[0061] Platinum with a thickness of 2 μm was deposited under the ion beam to connect to the electrode. The deposition voltage and current were 30 kV and 0.23 nA. According to the FIB extraction process of conventional samples, the length consistent with the DENS thermoelectric chip electrode was determined for extraction, and it was transferred and fixed to the two electrodes. After that, the platinum in the middle part of the electrolyte surface was milled to avoid short circuit of the micro battery. The schematic diagram of the micro battery is shown in the figure. Figure 3 shown.

[0062] Embodiment 3:

[0063] Observation of electrochemical reactions in micro solid-state alkali metal batteries

[0064] 1. Symmetrical battery observation cross section

[0065] Wipe the surface electrodes of the DENS thermoelectric chip clean, fix the DENS thermoelectric chip on the substrate through patch and curing, and use the wire bonding process to connect the DENS thermoelectric chip electrodes to the pads on the PCB substrate to form a reliable electrical connection; after completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the micro device to the copper wire through soldering to ensure the overall conduction of the circuit.

[0066] The solid electrolyte is selected according to actual needs. In the present invention, garnet LLZTO is selected, and the surface is polished with sandpaper with mesh numbers of 800, 2500, 2500, and 10000. The polishing time is 5min, 10min, 20min, and 30min, respectively, to remove the surface oxide layer and keep the surface flat. Then, it is quickly transferred to the chamber of the scanning electron microscope together with the micro-device and evacuated to a usable state.

[0067] Platinum with a thickness of 2 μm was deposited under the ion beam to connect to the electrode. The deposition voltage and current were 30 kV and 0.23 nA. According to the FIB extraction process of conventional samples, the length consistent with the DENS thermoelectric chip electrode was determined for extraction, and it was transferred and fixed to the two electrodes. After that, the platinum in the middle part of the electrolyte surface was milled to avoid short circuit of the micro battery. The schematic diagram of the micro battery is shown in the figure. Figure 3 shown.

[0068] Adjust the micro battery to face the electron beam to obtain the initial state interface. In the symmetrical battery, when the current was 3 mA, the growth of curly and columnar dendrites was observed under constant current charge and discharge conditions. Figure 4 As shown. As the charge and discharge process continues, the growth of dendrites shrinks, indicating the existence of creep migration of lithium dendrites. In addition, it can be seen from the electrochemical curve that the growth of dendrites will lead to a decrease in battery resistance, which is an important cause of short-circuit failure of solid-state alkali metal batteries. In the full battery, when in-situ observation was performed under charging conditions, microcracks were observed in the positive electrode material when the current was 1mA, as shown in Figure 2. Figure 4 shown.

[0069] 2. Full battery observation cross section

[0070] Wipe the surface electrodes of the DENS thermoelectric chip clean, fix the DENS thermoelectric chip on the substrate through patch and curing, and use the wire bonding process to connect the DENS thermoelectric chip electrodes to the pads on the PCB substrate to form a reliable electrical connection; after completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the micro device to the copper wire through soldering to ensure the overall conduction of the circuit.

[0071] The solid electrolyte is selected according to actual needs. In the present invention, garnet LLZTO is selected, and the surface is polished with sandpaper with mesh numbers of 800, 2500, 2500, and 10000. The polishing time is 5min, 10min, 20min, and 30min, respectively, to remove the surface oxide layer and keep the surface flat. In the present invention, graphite is selected as the negative electrode material and NCM is selected as the positive electrode material. Then, it is quickly transferred to the chamber of the scanning electron microscope together with the micro device and evacuated to a usable state.

[0072] Platinum with a thickness of 2 μm was deposited under the ion beam to connect to the electrode. The deposition voltage and current were 30 kV and 0.23 nA. According to the FIB extraction process of conventional samples, the length consistent with the DENS thermoelectric chip electrode was determined for extraction. The negative electrode material, electrolyte material, and positive electrode material were extracted one by one, transferred and fixed to the two electrodes, and then the platinum in the middle part of the electrolyte surface was milled to avoid short circuit of the micro battery. The schematic diagram of the micro battery is shown in the figure. Figure 3 shown.

[0073] Adjust the micro battery to face the electron beam to obtain the initial state interface. In the full battery, when the constant current charge and discharge conditions are observed in situ, when the current is 1mA and the charging time is about 30min, micro cracks are observed in the positive electrode material, such as Figure 4 shown.

[0074] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A micro device for dynamically observing electrochemical reactions of solid-state alkali metal batteries, characterized in that: It comprises a DENS thermoelectric chip and a PCB substrate, wherein the DENS thermoelectric chip and the PCB substrate are electrically connected; a gold pad and a copper circuit are arranged on one side of the PCB substrate, two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuit is connected to the copper wire solder to ensure the overall conduction of the circuit; a micro battery is arranged at the electrode of the DENS thermoelectric chip through FIB.

2. A micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 1, characterized in that: The two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads on the PCB substrate through wire bonding. The connection between the wire and the DENS thermoelectric chip adopts a wedge bonding method, and the connection with the PCB substrate adopts a ball bonding method.

3. A method for preparing a micro device for dynamically observing electrochemical reactions of solid-state alkali metal batteries, characterized in that: The preparation method is carried out according to the following steps: S1. Wipe the electrodes on the surface of the DENS thermoelectric chip clean, and then bond and solidify the cleaned DENS thermoelectric chip on the PCB substrate; S2. Use wire bonding technology to connect the electrodes of the DENS thermoelectric chip to the gold pads on the PCB substrate to form a reliable electrical connection; S3. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the copper circuit and the copper wire on the PCB substrate are connected by soldering to ensure the overall conduction of the circuit; S4. Use focused ion beam technology FIB to prepare micron-level thickness micro-batteries, and place the micro-batteries at the electrodes of micro-devices to observe the electrochemical reactions of solid-state alkali metal batteries under charging and discharging conditions.

4. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 3, characterized in that: In step S1, two electrodes on the surface of the DENS thermoelectric chip are cleaned with anhydrous ethanol having a content of ≥99.7% to remove contaminants. During the wiping process, it is necessary to avoid touching the silicon nitride film window to avoid damaging the electrode. The DENS thermoelectric chip used has a 50nm thick silicon nitride film window.

5. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 3, characterized in that: In step S1, the DENS thermoelectric chip is bonded and cured at a predetermined position on the PCB substrate using insulating glue, and the horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5-1 mm, providing conditions for subsequent wire bonding.

6. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 3, characterized in that: In step S2 , the wire bonding process is thermocompression bonding, ultrasonic bonding, or thermocompression-ultrasonic bonding.

7. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 6, characterized in that: The material used in the wire bonding process is a gold wire with a purity of 99.99%, a diameter of the gold wire of 20 μm, and an arc length of 5 mm; The bonding temperature of the wire bonding process is 150°C and the bonding time is 50 to 100 milliseconds. After the bonding is completed, the appearance of the solder joint is observed through a microscope to preliminarily judge the bonding quality.

8. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 3, characterized in that: In step S3, tin is used as solder, and the solder is heated with a soldering iron until it flows. When the solder flows to the gold pad, the soldering iron is quickly removed to complete the overall conduction of the circuit.

9. The method for preparing a micro-device for dynamically observing electrochemical reactions of solid-state alkali metal batteries according to claim 8, characterized in that: The conductivity test uses Chenhua electrochemical workstation to determine the conductivity of the circuit by measuring the resistance value. During the test, each solder joint and connection point is checked one by one to ensure that there is no open circuit or short circuit problem.

10. An application of a micro device, characterized in that: Rapidly transferring the solid electrolyte together with the micro-device according to any one of claims 1 to 9 to a chamber of a scanning electron microscope for observation of the electrochemical reaction, and evacuating the chamber to a usable state; Platinum with a thickness of 2μm is deposited under an ion beam to connect to the electrode. Under specific deposition voltage and current, the FIB extraction process of conventional samples is followed to determine the length that matches the DENS thermoelectric chip electrode for extraction. The negative electrode material, electrolyte material, and positive electrode material are extracted one by one, transferred and fixed to the two electrodes, and then the platinum in the middle part of the electrolyte surface is milled to avoid short circuit of the micro battery.

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