Microdevices for dynamic observation of electrochemical reactions in solid-state alkali metal batteries, their fabrication methods and applications

Abstract

This invention discloses a microdevice for dynamically observing the electrochemical reactions of solid-state alkali metal batteries, its fabrication method, and its application. The fabrication method includes: S1, cleaning the electrodes on the surface of a DENS thermoelectric chip, and then bonding and solidifying the cleaned DENS thermoelectric chip onto a PCB substrate; S2, connecting the electrodes of the DENS thermoelectric chip to gold pads on the PCB substrate using wire bonding technology to form a reliable electrical connection; S3, after completing the connection between the DENS thermoelectric chip and the PCB substrate, connecting the copper circuit and copper wires on the PCB substrate with solder to ensure overall circuit conductivity; S4, placing the micro-battery at the electrodes of the microdevice for observing the electrochemical reactions of the solid-state alkali metal battery under charge and discharge conditions. The microdevice of this invention possesses multi-scale characterization capabilities, enabling the acquisition of high-resolution surface morphology images in scanning electron microscopy (SEM), while simultaneously allowing for further sample thinning to facilitate high-resolution fine characterization in the same location using transmission electron microscopy.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery characterization technology, and in particular to a micro-device for dynamic observation of electrochemical reactions in solid-state alkali metal batteries using scanning electron microscopy, its preparation method and application. Background Technology

[0002] With the rapid development of integrated circuits and micro / nano chip technologies, especially in smartphones, IoT devices, and high-performance computing, the demand for efficient and reliable energy support is increasing. Traditional lithium-ion batteries typically use liquid electrolytes, which are flammable and chemically unstable, easily posing safety hazards such as fires and explosions. Micro solid-state alkali metal batteries, employing solid electrolytes, significantly improve safety and reduce the risk of leakage and combustion. However, electrochemical reactions during charging and discharging can still lead to battery failure. For example, the formation of lithium or sodium dendrites can puncture the electrolyte, causing a short circuit; simultaneously, mechanical failure of the electrolyte can lead to battery polarization, thus affecting overall performance. These failure mechanisms indicate the need to develop suitable micro-devices and characterization methods to monitor performance changes and failure processes in micro-batteries, enabling real-time evaluation and design improvement to enhance battery reliability and lifespan.

[0003] Therefore, conventional optical and X-ray microscopy characterization methods currently used have low spatial resolution and are not effectively applicable to local interface studies. Electron microscopy can observe the microstructure and morphological changes of materials at nanometer-level resolution, revealing their relationship with battery performance. Through energy dispersive spectroscopy (EDS), this technique can also provide information on the elemental composition of materials, helping to identify the reaction mechanisms at the electrode-electrolyte interface.

[0004] Current research primarily utilizes bias voltage application, such as Yang Yong et al.'s (ChemomechanicalFailure Mechanism Study in NASICON-Type Li 1.3 Al 0.3 Ti 1.7A series of studies have been conducted on the interface between LATP and lithium using in-situ TEM observation of (PO4)3 Solid-State Lithium Batteries. However, these studies only observe local areas and not under actual operating conditions. Other studies primarily involve constructing micro / nanoscale battery models and then performing real-time dynamic observation using transmission electron microscopy (TEM). In-situ TEM observation reveals details such as lattice distortion, defect formation, and phase transitions in the LiCoO2 cathode material during electrochemical delithiation. While TEM provides high-resolution images, it only offers two-dimensional information and cannot fully reflect the three-dimensional structural changes of battery materials, limiting the understanding of some complex electrochemical processes. However, scanning electron microscopy (SEM) can generate high-resolution surface images, revealing characteristics such as particle size, surface cracks, and deposits in electrode materials; fibrillation-based battery (FIB) can prepare micron-scale battery samples, which can be observed in detail under SEM conditions, more closely resembling actual battery conditions. Meanwhile, cryo-assisted dual-beam (Cryo FIB-SEM) technology is used to reduce electron beam damage to the sample, thereby obtaining non-destructive three-dimensional morphological information. Nevertheless, achieving in-situ dynamic observation of the electrochemical reactions of micron-scale solid-state batteries in scanning electron microscopy remains very challenging, due to factors such as the fabrication of microcells and the lack of suitable microdevices. Therefore, continuous development and improvement of existing technologies and methods are necessary. Summary of the Invention

[0005] To address the aforementioned technical problems in the existing technology, this invention provides a micro-device for dynamically observing the electrochemical reactions of solid-state alkali metal batteries in a scanning electron microscope, along with its preparation method and application, thereby enabling the observation of electrochemical reactions in micro solid-state alkali metal batteries in a scanning electron microscope.

[0006] The technical solution adopted in this invention is:

[0007] A microdevice for dynamically observing the electrochemical reaction of a solid-state alkali metal battery is characterized by comprising a DENS thermoelectric chip and a PCB substrate, wherein the DENS thermoelectric chip and the PCB substrate are electrically connected; gold pads and copper circuits are provided on one side of the PCB substrate, the two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuits are connected to copper wire solder to ensure the overall conductivity of the circuit; a micro battery is set at the electrode of the DENS thermoelectric chip using FIB.

[0008] Furthermore, the two electrodes of the DENS thermoelectric chip are connected to gold pads on the PCB substrate via wire bonding. The connection between the wires and the DENS thermoelectric chip is a wedge bonding method, and the connection between the wires and the PCB substrate is a ball bonding method.

[0009] A method for fabricating a microdevice for dynamically observing the electrochemical reactions of a solid-state alkali metal battery, characterized in that the fabrication method comprises the following steps:

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

[0011] S2. The electrodes of the DENS thermoelectric chip are connected to the gold pads on the PCB substrate using wire bonding technology to form a reliable electrical connection.

[0012] S3. After completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the copper circuit and copper wire on the PCB substrate with solder to ensure the overall conductivity of the circuit.

[0013] S4. Place the micro battery at the electrode of the micro device to observe the electrochemical reaction of the solid alkali metal battery under charge and discharge conditions.

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

[0015] Furthermore, in step S1, insulating adhesive is used to attach and cure the DENS thermoelectric chip at a predetermined position on the PCB substrate. The horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5 to 1 mm, which provides conditions for subsequent wire bonding.

[0016] Furthermore, a single-sided PCB substrate with dimensions of 10*10*0.8mm and gold pads and copper circuitry is selected. The pads on the PCB substrate used for lead wires have a diameter of 300μm, and the pads used for connection with copper wires have a diameter of 800μm.

[0017] Furthermore, in step S2, the wire bonding process is thermo-press bonding, ultrasonic bonding, or thermo-press ultrasonic bonding.

[0018] Furthermore, the wire bonding process uses gold wire with a purity of 99.99%, and the gold wire has a diameter of 20 μm and an arc length of 5 mm.

[0019] The bonding temperature for the wire bonding process is 150℃, and the bonding time is 50-100 milliseconds. After bonding is completed, the shape of the solder joint is observed under a microscope to make a preliminary judgment on the bonding quality.

[0020] Furthermore, the specific bonding process is as follows: The capillary is moved above the pad and aligned with its center; the capillary is lowered so that the gold ball contacts the pad; simultaneously, ultrasonic energy, pressure, and heat are applied to complete the first bonding operation. After bonding, the capillary is moved upwards to pull out the gold wire, forming an arc-shaped loop; the loop height and shape are controlled to prevent the gold wire from being too tight or too loose, and the second bonding operation is completed using the same method.

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

[0022] Furthermore, the continuity test was conducted using a Chenhua electrochemical workstation. The circuit continuity was determined by measuring the resistance value. During the test, each solder joint and connection point was checked one by one to ensure that there were no open circuits or short circuits.

[0023] Furthermore, in step S4, micro-batteries with a thickness of micrometers are prepared using focused ion beam (FIB) technology, and their electrochemical reactions under charge and discharge conditions are observed.

[0024] An application of a microdevice is characterized in that a solid electrolyte is rapidly transferred together with the aforementioned microdevice to the chamber of a scanning electron microscope for observation of the electrochemical reaction, and the chamber is evacuated to a usable state.

[0025] A 2 μm thick platinum layer was deposited under an ion beam and connected to the electrode. The deposition voltage and current were 30 kV and 0.23 nA, respectively. Following the standard FIB extraction process for samples, the length that matched the DENS thermoelectric chip electrode was determined for extraction. The negative electrode material, electrolyte material, and positive electrode material were extracted in this way, transferred, and fixed onto the two electrodes. Then, the platinum in the middle part of the electrolyte surface was milled to avoid short circuits in the microcell.

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

[0027] 1. The microdevice provided by this invention has the ability to observe and monitor the electrochemical reactions of solid-state alkali metal batteries in real time and at high resolution. This is invaluable for improving battery performance and lifespan, as well as for better understanding the dynamic changes in the internal processes of the battery, thereby improving the efficiency of battery research and applications.

[0028] 2. The micro-devices provided by this invention have advantages such as simple structure and low manufacturing cost, making them easy to promote and apply. Their design and relatively few components make them easy to manufacture and operate, and reduce the number and complexity of parts.

[0029] 3. The microdevice provided by this invention possesses multi-scale characterization capabilities, enabling the acquisition of high-resolution surface morphology images in scanning electron microscopy (SEM) while simultaneously thinning the sample to allow for high-resolution, detailed characterization in transmission electron microscopy (TEM) at the same location. This design achieves multi-scale observation of the same region, allowing for a more comprehensive analysis of the sample's microstructure and properties. Attached Figure Description

[0030] Figure 1 A diagram of a micro-device provided for this invention.

[0031] Figure 2 This section describes the circuit continuity test method and the corresponding I-V curve.

[0032] Figure 3 This is a schematic diagram of a miniature battery.

[0033] Figure 4 Scanning electron microscope image of the electrochemical reaction occurring in a micro solid-state battery. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

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

[0037] refer to Figure 1 The present invention discloses a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery, comprising a DENS thermoelectric chip and a PCB substrate, wherein the DENS thermoelectric chip and the PCB substrate are electrically connected; gold pads and copper circuits are provided on one side of the PCB substrate, the two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuits are connected to copper wires by solder to ensure the overall conductivity of the circuit; a micro battery is provided at the electrode of the DENS thermoelectric chip.

[0038] Specifically, the two electrodes of the DENS thermoelectric chip are connected to gold pads on the PCB substrate via wire bonding. The connection between the wires and the DENS thermoelectric chip is a wedge bonding method, and the connection between the wires and the PCB substrate is a ball bonding method.

[0039] The present invention discloses a method for fabricating a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery, the method comprising the following steps:

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

[0041] Specifically, dip the tip of the filter paper into anhydrous ethanol with a content of ≥99.7% and clean the two current-carrying electrodes on the surface of the DENS thermoelectric chip to remove contaminants. During the wiping process, avoid touching the silicon nitride film window to prevent damage to the electrodes.

[0042] Specifically, insulating adhesive is used to attach and cure the DENS thermoelectric chip at a predetermined position on the PCB substrate. The horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5mm, which provides conditions for subsequent wire bonding.

[0043] S2. The electrodes of the DENS thermoelectric chip are connected to the gold pads on the PCB substrate using wire bonding technology to form a reliable electrical connection.

[0044] Specifically, select a single-sided PCB substrate with specifications of 10*10*0.8mm and gold pads and copper circuits. The diameter of the pads used for lead wires on the PCB substrate is 300μm, and the diameter of the pads used for connecting with copper wires 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 thermo-press ultrasonic bonding. The connection to the DENS thermoelectric chip adopts wedge bonding and the connection to the PCB substrate adopts ball bonding. This bonding method can maintain a high degree of flatness on the surface of the DENS thermoelectric chip, which facilitates the subsequent FIB sample preparation.

[0046] The specific bonding operation involves moving the capillary tube above the pad and aligning it with the center of the pad; lowering the capillary tube so that the gold ball contacts the pad; and simultaneously applying ultrasonic energy, pressure, and heat to complete the first bonding. After bonding is complete, the capillary tube moves upward to pull out the gold wire to form an arc-shaped loop; the height and shape of the loop are controlled to avoid the gold wire being too tight or too loose, and the second bonding is completed in the same way.

[0047] The wire bonding material is 99.99% pure gold wire with a diameter of 20 μm and an arc length of 5 mm. The ultrasonic power is 210 mV, the bonding pressure is 3.4 N, the bonding temperature is 150 °C, and the bonding time is 80 milliseconds. After bonding, the shape of the solder joints can be observed under a microscope to preliminarily determine the bonding quality. Figure 1 )

[0048] S3. After completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the copper circuit and copper wire on the PCB substrate with solder to ensure the overall conductivity of the circuit.

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

[0050] Continuity testing typically uses specialized testing equipment to determine the circuit's conductivity by measuring resistance. During the test, each solder joint and connection point is inspected to ensure there are no open or short circuits.

[0051] S4. Micro-batteries with micrometer-level thickness were fabricated using focused ion beam (FIB) technology, and their electrochemical reactions under charge-discharge conditions were observed.

[0052] Example 1:

[0053] Continuity testing of micro-devices

[0054] The surface electrodes of the DENS thermoelectric chip are cleaned, and the DENS thermoelectric chip is fixed on the substrate by surface mounting and curing. The electrodes of the DENS thermoelectric chip are connected to the pads on the PCB substrate using wire bonding technology to form a reliable electrical connection. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the micro-devices and copper wires are connected by solder to ensure the overall conductivity of the circuit.

[0055] With the circuit open, a Chenhua electrochemical workstation was used to connect the two copper wires of the two devices to obtain a linear sweep voltammetry curve. The initial potential was 0V, the termination potential was 1V, the sweep speed was 0.005V / s, and the sampling interval was 0.001V. Based on the relationship between voltage and current obtained from the curve, the circuit resistance can be calculated to be 10 ohms. 9 The magnitude is close to that of an open circuit.

[0056] The microdevice was fixed on a cylindrical sample stage with a 45° tilt. Platinum (15*1*2μm) was deposited using an ion beam to connect the positive and negative terminals of the microdevice, putting the circuit in a short-circuit state. A linear sweep voltammetry curve was tested under the same conditions using a Chenhua workstation, yielding a resistance of 310Ω, which is basically consistent with the theoretical value. This indicates that the device has good conductivity throughout and there are no short circuits or open circuits. Figure 2 )

[0057] Example 2:

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

[0059] The surface electrodes of the DENS thermoelectric chip are cleaned, and the DENS thermoelectric chip is fixed on the substrate by surface mounting and curing. The electrodes of the DENS thermoelectric chip are connected to the gold pads on the PCB substrate using wire bonding technology to form a reliable electrical connection. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the micro-devices and copper wires are connected by solder to ensure the overall conductivity of the circuit.

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

[0061] A 2 μm thick platinum layer was deposited under an ion beam and connected to the electrodes. The deposition voltage and current were 30 kV and 0.23 nA, respectively. Following the standard FIB extraction procedure for samples, the length corresponding to the DENS thermoelectric chip electrodes was determined and extracted. The platinum layer was then transferred and fixed onto the two electrodes. Subsequently, the platinum layer in the middle of the electrolyte surface was milled to avoid short circuits in the microcell. A schematic diagram of the microcell is shown below. Figure 3 As shown.

[0062] Example 3:

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

[0064] I. Observation cross section of symmetrical battery

[0065] The surface electrodes of the DENS thermoelectric chip are cleaned, and the DENS thermoelectric chip is fixed on the substrate by surface mounting and curing. The electrodes of the DENS thermoelectric chip are connected to the pads on the PCB substrate using wire bonding technology to form a reliable electrical connection. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the micro-devices and copper wires are connected by solder to ensure the overall conductivity of the circuit.

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

[0067] A 2 μm thick platinum layer was deposited under an ion beam and connected to the electrodes. The deposition voltage and current were 30 kV and 0.23 nA, respectively. Following the standard FIB extraction procedure for samples, the length corresponding to the DENS thermoelectric chip electrodes was determined and extracted. The platinum layer was then transferred and fixed onto the two electrodes. Subsequently, the platinum layer in the middle of the electrolyte surface was milled to avoid short circuits in the microcell. A schematic diagram of the microcell is shown below. Figure 3 As shown.

[0068] The microcell was positioned directly opposite the electron beam to obtain the initial interface. In symmetric cells, during in-situ observation under constant current charge-discharge conditions, the growth of coiled and columnar dendrites was observed at a current of 3 mA. Figure 4 As shown, dendrite growth retracts as the charging and discharging process continues, indicating the presence of lithium dendrite creep migration. Furthermore, the electrochemical curves show that dendrite growth leads to a decrease in battery resistance, a significant cause of short-circuit failure in solid-state alkali metal batteries. In the full cell, during in-situ observation under charging conditions, microcracks were observed in the positive electrode material at a current of 1 mA, such as... Figure 4 As shown.

[0069] II. Full Cell Observation Section

[0070] The surface electrodes of the DENS thermoelectric chip are cleaned, and the DENS thermoelectric chip is fixed on the substrate by surface mounting and curing. The electrodes of the DENS thermoelectric chip are connected to the pads on the PCB substrate using wire bonding technology to form a reliable electrical connection. After the connection between the DENS thermoelectric chip and the PCB substrate is completed, the micro-devices and copper wires are connected by solder to ensure the overall conductivity of the circuit.

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

[0072] A 2 μm thick platinum layer was deposited under an ion beam and connected to the electrode. The deposition voltage and current were 30 kV and 0.23 nA, respectively. Following the standard FIB extraction procedure for samples, the length corresponding to the DENS thermoelectric chip electrode was determined for extraction. The negative electrode material, electrolyte material, and positive electrode material were extracted in stages, transferred, and fixed onto the two electrodes. Then, the platinum layer in the middle of the electrolyte surface was milled to avoid short circuits in the microcell. A schematic diagram of the microcell is shown below. Figure 3 As shown.

[0073] The microcell was positioned directly opposite the electron beam to obtain the initial interface. During in-situ observation under constant current charge-discharge conditions within the full cell, microcracks were observed in the positive electrode material at a current of 1 mA and a charging time of approximately 30 minutes. Figure 4 As shown.

[0074] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery, characterized in that, The microdevice includes a DENS thermoelectric chip and a PCB substrate, which are electrically connected. A gold pad and a copper circuit are provided on one side of the PCB substrate. The two electrodes of the DENS thermoelectric chip are respectively connected to the gold pads, and the copper circuit is connected to copper wire solder to ensure the overall conductivity of the circuit. A micro battery is set at the electrode of the DENS thermoelectric chip through a FIB. 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 attach and solidify the cleaned DENS thermoelectric chip onto the PCB substrate. S2. The electrodes of the DENS thermoelectric chip are connected to the gold pads on the PCB substrate using wire bonding technology to form a reliable electrical connection. S3. After completing the connection between the DENS thermoelectric chip and the PCB substrate, connect the copper circuit and copper wire on the PCB substrate with solder to ensure the overall conductivity of the circuit. S4. Micro-batteries with micron-level thickness were prepared using focused ion beam (FIB) technology and placed at the electrodes of micro-devices to observe the electrochemical reactions of solid-state alkali metal batteries under charge and discharge conditions. The samples were further thinned to allow for high-resolution fine characterization by transmission electron microscopy (TEM) at the same location.

2. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, The two electrodes of the DENS thermoelectric chip are connected to gold pads on the PCB substrate by wire bonding. The connection between the wires and the DENS thermoelectric chip is a wedge bonding method, and the connection between the wires and the PCB substrate is a ball bonding method.

3. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, In step S1, anhydrous ethanol with a content of ≥99.7% is used to clean the two electrodes on the surface of the DENS thermoelectric chip to remove contaminants. During the wiping process, it is necessary to avoid touching the silicon nitride thin film window to avoid damaging the electrodes. The DENS thermoelectric chip used has a 50nm thick silicon nitride thin film window.

4. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, In step S1, insulating adhesive is used to attach and cure the DENS thermoelectric chip at a predetermined position on the PCB substrate. The horizontal distance between the edge of the DENS thermoelectric chip and the gold pad on the PCB substrate is 0.5~1mm, which provides conditions for subsequent wire bonding.

5. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, In step S2, the wire bonding process is hot-press bonding, ultrasonic bonding, or hot-press ultrasonic bonding.

6. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, The wire bonding process uses gold wire with a purity of 99.99%, and the gold wire has a diameter of 20 μm and an arc length of 5 mm. The bonding temperature for the wire bonding process is 150℃, and the bonding time is 50~100 milliseconds. After bonding is completed, the shape of the solder joint is observed under a microscope to make a preliminary judgment on the bonding quality.

7. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 1, characterized in that, In step S3, tin is used as solder, and the solder is heated to a flow state with a soldering iron. When the solder flows to the gold pad, the soldering iron is quickly removed to complete the overall conduction of the circuit.

8. The method for preparing a micro-device for dynamically observing the electrochemical reaction of a solid-state alkali metal battery as described in claim 7, characterized in that, The continuity test was conducted using the Chenhua Electrochemical Workstation. The continuity of the circuit was determined by measuring the resistance value. During the test, each solder joint and connection point was checked one by one to ensure that there were no open circuits or short circuits.

9. A method for preparing a micro solid-state alkali metal battery using a form-in-the-loop (FIB) substrate, characterized in that, The solid electrolyte and the microdevice described in claim 1 are rapidly transferred together to the chamber of a scanning electron microscope for observation of the electrochemical reaction, and the chamber is evacuated to a usable state. A 2μm thick platinum layer was deposited under an ion beam and connected to the electrode. Under specific deposition voltage and current, the length corresponding to the DENS thermoelectric chip electrode was determined and extracted according to the conventional sample FIB extraction process. The negative electrode material, electrolyte material, and positive electrode material were extracted in sequence, 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.

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