Processing method of packaging layer

Abstract

The invention belongs to the technical field of electrochemical in-situ characterization, and particularly relates to a packaging layer processing method for near-normal-pressure photoelectron spectroscopy analysis. The method comprises the following steps: constructing an initial packaging layer covering liquid electrolyte on the surface of a working electrode; integrating the samples on a sample carrying table and transferring the samples to an analysis equipment chamber; the thinning system of the equipment is used for carrying out in-situ thinning on a target area, the analysis beam of the equipment is synchronously or alternately used for monitoring the signal change of the thinned area in real time, and the thickness of the packaging layer is precisely regulated and controlled to the target nanoscale based on signal feedback. According to the method, through a strategy of first packaging and then in-situ optimization, the contradiction that effective sealing and high signal transmittance are difficult to consider in a traditional method is solved, high-quality in-situ and dynamic characterization of an electrode-electrolyte interface in a volatile liquid electrolyte environment is realized, and the accuracy and reliability of test data are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical in-situ characterization technology, specifically relating to a method for preparing and integrating an electrode interface encapsulation layer for (near) ambient pressure photoelectron spectroscopy ((N)AP-XPS), aiming to improve the reliability and accuracy of dynamic and in-situ studies of the working interface of secondary batteries containing liquid electrolytes. Background Technology

[0002] The performance and reliability of secondary batteries (such as metal-ion batteries, flow batteries, and solid-state batteries) fundamentally depend on the dynamic physicochemical reactions occurring at the electrode-electrolyte interface. These processes include the formation and evolution of the solid electrolyte interface (SEI) and the cathode electrolyte interface (CEI), as well as the resulting side reactions, transition metal dissolution, electrolyte decomposition, and dendrite growth. Real-time, in-situ characterization of these interfaces is crucial for revealing battery degradation mechanisms and guiding material and interface optimization.

[0003] X-ray photoelectron spectroscopy (XPS) is a powerful tool for this type of interfacial chemical analysis. However, the ultra-high vacuum environment required for traditional XPS is incompatible with volatile liquid electrolytes. The development of near-ambient pressure XPS (NAP-XPS) technology, by allowing operation at millibar pressures, has made it possible to achieve in-situ detection of the solid-liquid interface of operating batteries. However, the successful application of this technology depends on a core premise: how to effectively encapsulate the liquid electrolyte to prevent its volatilization while ensuring that the characteristic photoelectron signals from deep interfaces can be effectively detected. Because the inelastic mean free path of photoelectrons is extremely short (typically less than 10 nanometers in relevant media), any coating used to encapsulate the electrolyte must be extremely thin and highly "transparent" to electrons; otherwise, the interfacial signal will be severely attenuated or shielded.

[0004] Currently, the main methods for introducing liquid electrolytes into NAP-XPS, such as the "immersion-pull" method to form thin liquid films or the use of prefabricated two-dimensional materials for sealing, have made some progress, but still have significant limitations: First, it is difficult to achieve a gapless, globally tight bond between the prefabricated independent film and the actual electrode surface. Residual gaps can lead to localized electrolyte evaporation, interfacial instability, and additional signal scattering. Second, the control of the encapsulation layer thickness is often not precise or uniform enough, making it difficult to stably maintain it at the nanoscale required for optimal signal transmission, affecting the quantitative reliability of the data. Finally, existing methods are mostly based on highly simplified model systems, which lack compatibility with the complex porous electrode structures and long-term electrochemical cycling conditions in actual batteries.

[0005] Therefore, developing a high-quality encapsulation layer preparation and processing method capable of forming a tight, conformal contact with the electrode surface and precisely controlling its thickness to the target nanometer level in situ has become an urgent technical requirement for improving the accuracy and reliability of NAP-XPS in studying the interfaces of actual battery systems. This method aims to directly resolve the contradiction between "effective sealing" and "non-destructive signal detection," providing a key technical foundation for obtaining high-fidelity, dynamic interface evolution information. Summary of the Invention

[0006] This invention belongs to the interdisciplinary field of surface analysis technology and electrochemical characterization. Specifically, it relates to a method for preparing and precisely processing an electrode interface encapsulation layer for surface analysis technologies such as near-ambient pressure photoelectron spectroscopy (NAP-XPS), aiming to achieve high-fidelity in-situ interface characterization of electrochemical systems containing liquid electrolytes.

[0007] To achieve the above objectives, the encapsulation layer processing method provided by this invention has the following core concept: First, an initial sealing layer is constructed on the electrode surface to encapsulate the liquid electrolyte, forming a stable solid-liquid interface; then, in a vacuum or near-atmospheric pressure chamber of a surface analysis device, the sealing layer is subjected to in-situ, controllable thinning treatment, ultimately achieving an optimized thickness that effectively prevents electrolyte evaporation while allowing efficient transmission of detection signals. This method is particularly suitable for dynamic, in-situ studies of the electrode-electrolyte interface in volatile liquid electrolyte environments.

[0008] A specific encapsulation layer processing method includes the following steps:

[0009] S1. Interface Construction and Initial Sealing: An initial encapsulation layer is formed or attached to the test surface region of the working electrode, and a liquid electrolyte is introduced between this encapsulation layer and the electrode surface, thereby forming an initially encapsulated in-situ electrochemical interface. This constructed electrode interface assembly (typically including the working electrode, counter / reference electrode, electrolyte, and initial encapsulation layer) is assembled into a sealed housing of a dedicated sample stage. During assembly, it must be ensured that the initial encapsulation layer is positioned in the corresponding location of the pre-reserved incident channel (for excitation sources such as X-rays) on the housing.

[0010] S2. In-situ transfer and fixation: The sample stage is transferred to the analysis or pretreatment chamber of the surface analysis equipment (such as NAP-XPS) under the protection of an inert atmosphere, and is fixed stably to ensure the positioning accuracy of subsequent processing.

[0011] S3. In-situ Controlled Thinning: Using a thinning system integrated into or connected to the analytical equipment, in-situ thinning of a selected area of ​​the encapsulation layer (typically the focal spot area for optical / spectral detection) is performed within the chamber. By controlling the thinning process parameters, the thickness of the encapsulation layer is precisely adjusted to a preset target range.

[0012] S4. Thinning Endpoint Determination and Post-processing: During the thinning process or through intermittent monitoring, the physical or chemical state information of the thinned area of ​​the encapsulation layer is acquired in real time or near real time using the surface analysis equipment itself or additional monitoring methods, and the thinning endpoint is determined accordingly. After the target is reached, necessary post-processing can be performed, such as adjusting the chamber environment pressure or atmosphere to further stabilize the interface.

[0013] As a further optimization, refinement, or extension of this method, the following technical features can be used individually or in combination:

[0014] Thinning Method and Feedback Control: The thinning process can be achieved through one or more of the following methods: physical sputtering (e.g., using an inert gas ion beam), chemically assisted etching, or irradiation treatment (e.g., soft X-rays, electron beams). Simultaneously or intermittently during thinning, the thinned area can be irradiated with a probe beam (e.g., X-rays) from the surface analysis device, and the resulting characteristic signals (e.g., photoelectron spectroscopy) can be collected. By analyzing the changes in this signal over thinning time, it can be used as a basis for judging the thinning progress and endpoint, enabling feedback control and preventing excessive thinning that could damage the underlying interface.

[0015] Precise positioning and region selection: Before in-situ thinning, the moving mechanism of the sample stage or the beam deflection / focusing function of the thinning system itself can be used to precisely align the thinning action with the predefined region on the initial encapsulation layer, ensuring the uniformity and consistency of the encapsulation layer thickness in the subsequent characterization region.

[0016] Electrode surface pretreatment: Before step S1, the surface of the working electrode to be tested can be pretreated to form a region with higher microscopic flatness. Pretreatment methods may include, but are not limited to, mechanical polishing, ion beam polishing, or focused ion beam processing. This helps improve the uniformity of adhesion between the initial encapsulation layer and the surface, and reduces interfacial voids.

[0017] Initial encapsulation layer formation method: The initial encapsulation layer can be formed using the following two main strategies. In actual operation, the selection and optimization should be based on the encapsulation layer material properties, electrode surface condition, and system sealing requirements:

[0018] (1) Pre-forming-transfer bonding strategy: In an inert atmosphere, liquid electrolyte is first applied to the electrode surface, and then a separately prepared thin film (such as two-dimensional layered material, polymer support film, etc.) is precisely transferred and covered on it, so that it is tightly bonded to the electrode surface and electrolyte.

[0019] (2) In-situ direct growth / deposition strategy: In a controlled atmosphere, a uniform and dense initial encapsulation layer is first formed directly on the smooth area of ​​the electrode using methods such as chemical vapor deposition, atomic layer deposition, spin coating, or Langmuir-Blodgett. Subsequently, liquid electrolyte is introduced under this encapsulation layer through microfluidic injection or capillary action.

[0020] Environmental and pressure control: After the thinning process in step S3 is completed, high-purity inert gas or saturated vapor of electrolyte can be backfilled into the chamber to balance and maintain a test environment pressure that is conducive to interface stability and compatible with analytical equipment.

[0021] Beneficial effects:

[0022] 1. Resolves the contradiction between sealing and detection: By adopting a two-step strategy of "first encapsulation, then in-situ optimization," the problem of traditional methods where one-time sealing cannot simultaneously achieve "complete anti-evaporation" and "high transmittance" is fundamentally solved. Initial encapsulation ensures the stability of the electrolyte during transfer and preliminary processing, while subsequent in-situ thinning can precisely optimize the encapsulation layer thickness to the nanoscale that is most favorable for the detection signal.

[0023] 2. Achieved precise thickness control and interface fidelity: By utilizing the surface analysis equipment's own or integrated monitoring methods for feedback control, it is possible to achieve nanometer-level precise control of the encapsulation layer thickness and ensure that thinning stops at the optimal interface exposure state, thus preserving the true electrode-electrolyte interface information to the greatest extent and avoiding signal annihilation due to excessive encapsulation layer thickness or interface damage due to excessive thinness.

[0024] 3. Improved versatility and reliability: This method has good compatibility with electrode types (such as planar electrodes and porous electrodes), electrolyte types, and thin film materials. Its core lies in the subsequent in-situ thinning and optimization steps, reducing over-reliance on the perfection of the initial encapsulation and improving the success rate and repeatability of the entire process.

[0025] 4. Enhanced in-situ characterization capabilities: Samples prepared and optimized using this method have uniform and optimal encapsulation layer thickness, making them ideal for use with electrochemical workstations to conduct true operando characterization. This allows for real-time and dynamic monitoring of key interface processes such as SEI / CEI formation and evolution, providing high-quality data for understanding the reaction mechanisms of batteries and other electrochemical systems. Attached Figure Description

[0026] Figure 1 This is a flowchart of the encapsulation layer processing method provided in the embodiments of the present invention;

[0027] Figure 2This is a partial structural schematic diagram of the sample stage provided in an embodiment of the present invention from a first-view perspective;

[0028] Figure 3 This is a partial structural schematic diagram of the sample stage provided in an embodiment of the present invention from a second perspective.

[0029] In the picture:

[0030] 1. Base; 2. Housing; 21. Main body; 22. Top cover; 221. Injection channel; 31. Working electrode; 4. Thin film. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0035] like Figures 1 to 3As shown, this embodiment provides a method for fabricating an electrochemical interface encapsulation layer for surface analysis. This method constructs an initial encapsulation layer on the surface of the working electrode and optimizes it in situ to obtain the final encapsulation layer. This achieves effective encapsulation of the liquid electrolyte and efficient transmission of detection signals, aiming to significantly improve the data quality and accuracy of surface analysis techniques such as near-ambient pressure photoelectron spectroscopy (NAP-XPS) when performing in-situ interface characterization of electrochemical systems such as batteries.

[0036] like Figure 1 As shown, this method mainly includes two core stages: the first stage is "interface construction and initial sealing," which involves forming an initial encapsulation layer covering the electrolyte on the electrode surface in an inert environment; the second stage is "in-situ precision thinning and optimization," which involves controllably thinning the encapsulation layer to the target nanometer thickness within the analytical equipment chamber. The specific steps are as follows:

[0037] Phase 1: Interface Construction and Initial Sealing

[0038] Step S1: Form an initial encapsulation layer on the surface of the working electrode to confine the liquid electrolyte between the working electrode surface and the initial encapsulation layer; assemble the assembly carrying the working electrode and the initial encapsulation layer onto the sample stage and transfer it to the chamber of the surface analysis equipment; the sample stage has a sealed housing with an entrance window, and during assembly, it must be ensured that the initial encapsulation layer is aligned with the entrance window.

[0039] Step S11: Perform a planarization pretreatment on the surface to be tested of the working electrode.

[0040] To improve the uniformity of the encapsulation layer adhesion and reduce the interface voids, the test area of ​​the working electrode is first subjected to surface planarization treatment. The planarization pretreatment includes surface treatment by ion beam polishing, mechanical polishing or chemical mechanical polishing processes.

[0041] In this example, focused ion beam (FIB) technology is used to process the surface of the working electrode loaded with active material. Through a multi-step process, a smooth region with a diameter of several millimeters and a surface roughness (Ra) better than or equal to 10 nm is prepared on the electrode surface. This smooth region provides an ideal substrate for the subsequent formation of a uniform and dense initial encapsulation layer. Alternatively, techniques such as helium ion microscopy (HIM) or low-energy inert gas cluster beam polishing can be used to reduce potential ion implantation contamination.

[0042] Taking the working electrode 31 as an example, it is a three-dimensional electrode loaded with active material; the preset roughness value is 5 nm, and the preset flatness threshold is 10 nm. The working electrode 31 is placed in a dual-beam FIB-SEM apparatus (integrating focused ion beam (FIB) and scanning electron microscope (SEM)). Focused ion beam processing is performed using an ion beam. A high-current ion beam is used for roughing to quickly remove excess material, then the ion beam current is reduced to a medium range for finishing, and further reduced to a minimum for fine processing. This reduces the contact gap of the subsequent encapsulation layer from the micrometer level to the nanometer level. class It enhances the interface signal intensity by minimizing scattering and improves NAP-XPS detection of buried interfaces; it also prevents the rough working electrode 31 surface from causing poor initial encapsulation layer adhesion and large air gaps, which would severely attenuate the photoelectron signal due to the limitation of inelastic mean free path.

[0043] Step S12: Liquid electrolyte introduction and initial encapsulation layer encapsulation.

[0044] In an inert atmosphere, a trace amount of liquid electrolyte is precisely applied to the smooth area of ​​the working electrode 31, with a thin film serving as the initial encapsulation layer. Subsequently, encapsulation is performed using a "pre-formed thin film transfer method": a separately prepared thin film (e.g., a single-layer or few-layer two-dimensional layered material or polymer film) is used as the initial encapsulation layer and transferred onto the electrolyte droplet using wet or dry transfer techniques. With the mechanical pressure of the sample stage housing, a global, bubble-free, and tight bond is ensured between the initial encapsulation layer and the smooth area of ​​the working electrode, with the contact gap between them controlled to an extremely low level. This step constructs a preliminary stable "electrolyte-thin film" encapsulation system.

[0045] As an alternative, the "in-situ thin film deposition method" can also be used: first, a dense thin film (such as a two-dimensional layered material or polymer film) is directly grown on the smooth area of ​​the electrode using methods such as atomic layer deposition (ALD) or chemical vapor deposition (CVD) as the initial encapsulation layer, and then the electrolyte is introduced into the gap between the encapsulation layer and the working electrode by capillary injection or microfluidic methods.

[0046] In some embodiments, in an inert gas environment, a thin film can be directly deposited onto a smooth region via a chemical reaction before adding the liquid electrolyte, and then the liquid electrolyte is injected between the film and the smooth region. Specifically, before adding the liquid electrolyte, a thin film is grown on a clean electrode surface using chemical vapor deposition (CVD) to avoid thermal decomposition of the liquid. After CVD, the liquid electrolyte is added using a physical contact method or an electrochemical injection method, or channels are pre-drilled on the electrode for liquid electrolyte injection. If the physical contact method is used, the liquid electrolyte is directly applied or coated onto the electrode surface where the initial encapsulation layer has been deposited, allowing it to penetrate to the interface between the encapsulation layer and the electrode through capillary action or gravity. If the electrochemical injection method is used, the electrode is immersed in the liquid electrolyte, and a voltage is applied to drive electrolyte ions to migrate into the initial encapsulation layer, achieving uniform filling.

[0047] It should be noted that physical contact is not suitable for dense initial encapsulation layers, while electrochemical implantation may have potential side reactions. It is preferable to first apply liquid electrolyte and then use a wet transfer method to transfer the pre-prepared initial encapsulation layer to the smooth area of ​​the working electrode.

[0048] Step S13: Sample stage integration and sealing.

[0049] The pre-encapsulated electrode assembly (including the working electrode, counter electrode, and reference electrode) is assembled into the sealed housing of a dedicated sample stage. During assembly, ensure that the initial encapsulation layer is aligned with the dedicated X-ray entrance window on the housing. The overall design of the sample stage guarantees vacuum sealing and reliable electrical connections during transfer and testing.

[0050] In this embodiment, the sample stage includes a base 1, a housing 2, a working electrode 31, and an encapsulation layer 4. The encapsulation layer 4 serves as the initial encapsulation layer. The housing 2 includes a main body 21 fixed to the base 1 and a top cover 22 fixed above the main body 21. The top cover 22 has a central through-hole injection channel 221, and its side facing the main body 21 is used to position the encapsulation layer 4. The top cover 22 and the main body 21 are fixed to the base 1 by four screws. The top cover 22 can be quickly disassembled, making it directly compatible with various instruments. It allows for characterization of the same area without complex repositioning, thereby ensuring the consistency and efficiency of the analysis.

[0051] The working electrode 31 is placed inside the main body 21 with its smooth area facing upwards. The encapsulation layer 4 covers this area, and then the top cover 22 is fixed to the main body 21 and the base 1 with screws. Under the pressure of the top cover 22, the encapsulation layer 4 makes tight contact with the smooth area, without bubbles or wrinkles, achieving a suitable contact gap. The incident channel 221 on the top cover 22 is aligned with the encapsulation layer 4, allowing incident light to enter the incident channel 221 and interact with the encapsulation layer 4.

[0052] The sample stage also includes a counter electrode and a reference electrode located inside the main body 21. The working electrode 31, the counter electrode, and the reference electrode work together to perform precise electrochemical measurements. Their specific configuration, the working principle of the sample stage, and the detailed assembly method all follow existing technology and will not be described in detail here.

[0053] After the sample stage is assembled, its base 1 is horizontally fixed to the analytical equipment. The working electrode 31, counter electrode, and reference electrode inside the main body 21 are stacked vertically, but horizontally. This embodiment uses X-ray photoelectron spectroscopy as an example; the analytical equipment is a (near) atmospheric pressure X-ray photoelectron spectrometer, with the encapsulation layer 4 facing the differential pump orifice. Pressure is regulated via the differential pump system, following standard electrochemical pre-test preparation procedures, which will not be detailed here. In other embodiments, it can also be applied to other spectra, such as ultraviolet photoelectron spectroscopy, reflected photoelectron spectroscopy, Auger electron spectroscopy, etc.

[0054] Phase Two: In-situ Precision Thinning and Optimization

[0055] Step S2: Inside the chamber, the target area of ​​the initial encapsulation layer is thinned in situ using the thinning function of the surface analysis equipment; during the thinning process or through intermittent operation, the target area is monitored using the probe beam of the surface analysis equipment, and the thinning process is controlled based on the changes in the collected signals until the initial encapsulation layer is thinned to the target thickness.

[0056] Step S21: Pollution-free transfer and location.

[0057] The sample stage is transferred to the NAP-XPS spectrometer's analysis chamber or dedicated pretreatment chamber without exposure to the atmosphere via an interconnected transport system. A precision sample manipulator within the chamber is used to fix and position the sample stage, ensuring precise alignment of the encapsulation layer to be processed with the path of the ion beam or other thinning beam.

[0058] Step S22: In-situ monitored thinning.

[0059] The thinning process is selected from one or more of the following: low-energy ion beam sputtering, gas cluster ion beam etching, soft X-ray irradiation, or electron beam irradiation.

[0060] During the thinning process, the intensity of the characteristic signal from the liquid electrolyte is monitored. If the intensity of the characteristic signal increases with the thinning time, the thinning process continues. When the intensity of the characteristic signal reaches a stable plateau and the chamber environment remains stable, the thinning process is stopped. Throughout the thinning process, the chamber environment is under low pressure, and the vacuum level of the chamber environment remains stable.

[0061] Step S221: Start the thinning system integrated into the analysis equipment (e.g., a low-energy argon ion gun or a gas cluster ion beam source) to perform gentle, controlled layer-by-layer sputtering etching on a specific area of ​​the encapsulation layer (usually corresponding to the spot position of subsequent spectral detection).

[0062] Step S222: The core of the thinning process lies in "real-time monitoring and feedback control":

[0063] During etching intervals or with a specific configuration, synchronous monitoring is achieved by irradiating the thinning region with an X-ray source from the NAP-XPS and collecting its photoelectron spectrum.

[0064] In most spectrometers, the analysis chamber and the etching chamber are independent functional units: the etching chamber is responsible for etching, while the analysis chamber performs spectral analysis. The sample stage can be moved between the two chambers via mechanical vacuum transfer. For example, the sample stage can be fixed in the etching chamber, and the spectrometer's etching system can perform in-situ layer-by-layer etching of the central region of the encapsulation layer to achieve thinning; during the etching intervals, it can be transferred to the analysis chamber for spectral analysis.

[0065] In integrated devices, such as the NAP-XPS system with coupled etching and analysis capabilities, etching and in-situ analysis can be performed simultaneously without transfer, thereby reducing the risk of damage to the encapsulation layer during operation.

[0066] Step S223: Track the intensity evolution of specific characteristic peaks in real time. For example, monitor the characteristic signals from the liquid electrolyte solvent and confirm the thinning effect through changes in the signals.

[0067] The initial encapsulation layer undergoes controlled in-situ thinning, with simultaneous monitoring of the signal response of the underlying components. The thinning progress is assessed in real time by tracking the intensity evolution of specific spectral features (such as signals from the liquid electrolyte solvent). The thinning endpoint is determined when the relevant signals stabilize or reach a predetermined threshold. At this point, the initial encapsulation layer is optimized to a suitable thickness that effectively blocks electrolyte evaporation while minimizing photoelectron signal attenuation, thereby avoiding electrolyte leakage or interface damage caused by excessive etching.

[0068] In this embodiment, an integrated low-damage ion source or beam can be used to perform in-situ, controllable layer-by-layer thinning in a selected area of ​​the initial encapsulation layer. During the thinning process, by acquiring spectral information in real time, the signal changes of characteristic components can be monitored simultaneously, thereby determining the depth of the thinned layer and the chemical state of the interface.

[0069] The aforementioned endpoint determination method based on spectral signal feedback does not require external auxiliary characterization equipment and has the advantages of being in-situ, objective, and quantifiable. In other embodiments, other types of excitation sources or beams can also be used for thinning, and other in-situ surface analysis techniques can be used to simultaneously monitor the composition of the outermost layer.

[0070] In this embodiment, an in-situ layer-by-layer thinning process is used to process the initial encapsulation layer. This process determines the thinning progress by real-time monitoring of the spectral characteristic signals from the encapsulated system. When characteristic signals related to the liquid electrolyte begin to appear and show regular changes, it indicates that the liquid-solid interface region is approaching, and controlled thinning continues at this point. The appropriate thinning endpoint is determined when the signal strengthens to a stable state. This method optimizes the initial encapsulation layer thickness to a level that satisfies both barrier functions and facilitates optoelectronic signal transmission, while avoiding excessive thinning that could lead to encapsulation failure or interface damage.

[0071] This thinning process allows for selective control of the initial encapsulation layer's thickness without compromising its overall sealing and structural integrity. This maintains stability of the liquid system under near-normal pressure while optimizing the transmission efficiency of optoelectronic signals and enhancing the detection intensity of interface-sensitive signals. Based on in-situ monitoring and feedback control using an integrated device platform, this method achieves dynamic adjustment and signal enhancement of the initial encapsulation layer thickness without the need for additional customized components, supporting clear analysis of interface reaction information.

[0072] Step S23: Post-processing and stabilization.

[0073] The target thickness ranges from 1 nanometer to 20 nanometers. Once the target thickness is reached, the thinning process is stopped.

[0074] After the thinning process is stopped, high-purity inert gas or saturated vapor of liquid electrolyte can be backfilled into the chamber to adjust and stabilize the ambient pressure within the optimal operating range of NAP-XPS, thereby balancing the pressure difference, further suppressing residual volatilization, and creating a stable environment for subsequent in-situ electrochemical-spectroscopy coupled testing.

[0075] The encapsulation layer processing method of this invention successfully reconciles the inherent contradiction between "effective sealing" and "signal transmission" through a two-step strategy of "complete encapsulation followed by in-situ optimization": First, the encapsulation layer is tightly bonded to the smooth area of ​​the working electrode to encapsulate the liquid electrolyte and eliminate interfacial gaps. Then, the encapsulation layer is thinned in-situ, in real-time, under monitored conditions within the analytical apparatus chamber. This process utilizes the device's own detection signal as feedback to actively and precisely control the film thickness to the optimal nanoscale. This method not only significantly enhances the photoelectron signal intensity from the intrinsic interface and greatly reduces artifacts introduced by excessive encapsulation layer thickness or interface inhomogeneity, thus obtaining more realistic and accurate dynamic chemical information; its core in-situ optimization step also reduces the stringent requirements for initial encapsulation perfection, making the process widely adaptable and more repeatable to different electrode systems, electrolytes, and encapsulation layer materials. Ultimately, the samples prepared by this method provide an ideal platform for use with an electrochemical workstation to carry out high spatiotemporal resolution operando characterization, enabling real-time tracking of dynamic interface processes such as SEI / CEI formation, thereby providing strong technical support for deepening the understanding of complex electrochemical systems such as secondary batteries.

[0076] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for fabricating an electrochemical interface encapsulation layer for surface analysis, characterized in that, Includes the following steps: An initial encapsulation layer is formed on the surface of the working electrode to confine the liquid electrolyte between the working electrode surface and the initial encapsulation layer; the assembly carrying the working electrode and the initial encapsulation layer is assembled on a sample stage and transferred to the chamber of the surface analysis equipment; the sample stage has a sealed housing with an entrance window, and during assembly, it must be ensured that the initial encapsulation layer is aligned with the entrance window; Inside the chamber, the surface analysis device is used to perform in-situ thinning of the target area of ​​the initial encapsulation layer. During the thinning process or through intermittent operation, the target area is monitored using the probe beam of the surface analysis device, and the thinning process is controlled based on the collected signal changes until the initial encapsulation layer is thinned to the target thickness.

2. The processing method according to claim 1, characterized in that, The steps of the thinning process based on feedback control of the collected signal changes include: monitoring the intensity of the characteristic signal from the liquid electrolyte; continuing the thinning process when the intensity of the characteristic signal increases with the thinning process time; and stopping the thinning process when the intensity of the characteristic signal reaches a stable plateau and the chamber environment remains stable.

3. The processing method according to claim 2, characterized in that, After the thinning process is stopped, the process also includes introducing an inert gas or saturated vapor of the liquid electrolyte into the chamber to regulate and stabilize the chamber environment.

4. The processing method according to claim 1, characterized in that, The thinning process is selected from one or more of the following: low-energy ion beam sputtering, gas cluster ion beam etching, soft X-ray irradiation, or electron beam irradiation.

5. The processing method according to claim 1, characterized in that, Before performing the in-situ thinning process, the process also includes a pre-treatment step of planarizing the surface of the working electrode.

6. The processing method according to claim 5, characterized in that, The surface smoothing pretreatment includes treating the surface using ion beam polishing, mechanical polishing, or chemical mechanical polishing processes.

7. The processing method according to claim 1, characterized in that, The formation of the initial encapsulation layer on the surface of the working electrode includes: The liquid electrolyte is applied to the surface of the working electrode; An independently prepared encapsulation layer is transferred and applied over the liquid electrolyte as the initial encapsulation layer, so that it forms a tight fit with the surface of the working electrode.

8. The processing method according to claim 1, characterized in that, Forming an initial encapsulation layer on the surface of the working electrode includes: First, a thin film is formed on the surface of the working electrode as the initial encapsulation layer by a deposition process. The liquid electrolyte is then introduced into the gap between the encapsulation layer and the surface of the working electrode.

9. The processing method according to claim 7 or 8, characterized in that, The encapsulation layer is made of polymer film, low-dimensional layered material, metal oxide film, or functional film with nanoscale pores.

10. The method according to claim 1 or 2, characterized in that, The thinning process is controlled by feedback based on the signal changes until the initial encapsulation layer is thinned to a thickness range of 1 nanometer to 20 nanometers.

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