Electrochemical in-situ characterization method and electrochemical integrated system

Abstract

The invention belongs to the technical field of electrochemistry and surface analysis testing, and discloses an electrochemical in-situ characterization method and an electrochemical integration system.The method comprises the steps that in a controllable inert atmosphere low-pressure environment, a liquid electrolyte is sealed through a packaging layer, the liquid electrolyte and an electrode are assembled into a closed total battery, and the closed total battery is integrated on a special sample carrying table; the sample carrying table is transferred to an analysis chamber of the near-normal-pressure X-ray photoelectron spectrometer without exposure through interconnection transmission; the battery is connected with an external electrochemical workstation in the cavity, and interface photoelectron spectrograms are synchronously acquired during charging and discharging, so that in-situ characterization of dynamic changes of chemical components on the surface of the battery is realized. According to the scheme, through double guarantee of physical isolation of the packaging layer and the inert atmosphere, zero air exposure and complete sealing operation in the whole process from battery assembly to test are achieved, volatilization and decomposition of liquid electrolyte are effectively inhibited, and a key technical means is provided for revealing real interface reaction kinetics of the battery.

Description

Technical Field

[0001] This invention relates to the field of electrochemical and surface analysis and testing technology, and in particular to an electrochemical in-situ characterization method and an integrated electrochemical system. Background Technology

[0002] The performance of secondary batteries (including metal-ion batteries, flow batteries, and solid-state batteries) is highly dependent on the dynamic physicochemical processes at the electrode-electrolyte interface, such as the formation and evolution of the solid electrolyte interface (SEI) and the cathode electrolyte interface (CEI). However, traditional ultra-high vacuum X-ray photoelectron spectroscopy (UHV-XPS) typically requires a vacuum level below 10⁻⁶. -9 The mbar concentration makes in-situ observation impossible in a real electrochemical environment. Samples must be disassembled, transferred, and prepared under non-operating conditions, a process that significantly alters the intrinsic state of the sensitive interface layer. For example, some components in the SEI are extremely sensitive to air and humidity, and irreversible decomposition or transformation will occur upon exposure, causing the measured components to deviate from the actual situation during battery operation, thus making it difficult to accurately reflect the dynamic evolution mechanism of the interface.

[0003] In recent years, near-atmospheric pressure X-ray photoelectron spectroscopy ((N)AP-XPS) has enabled real-time monitoring of surface chemical composition and electronic structure under gas-solid or gas-liquid coexistence conditions by increasing the detection pressure to the range of 2–30 mbar. This technology has achieved breakthroughs in fields such as electrocatalysis, enabling direct monitoring of binding energy shifts caused by potential gradients and the dynamic behavior of reaction intermediates, providing a key means for understanding interfacial processes. In secondary battery research, NAP-XPS has been preliminarily used to reveal the multilayer structure of SEI / CEI and its evolution under complex environments, establishing some correlations between interfacial properties and battery performance.

[0004] Nevertheless, directly applying this technology to in-situ characterization of secondary batteries containing liquid electrolytes still faces a series of challenges. On the one hand, common organic liquid electrolytes are highly volatile, and the vapor pressure required for their stable existence is usually higher than the conventional operating pressure range of NAP-XPS. Therefore, special designs such as thin liquid films, meniscus constraints, or micro-sealed cells must be used to introduce a liquid environment. However, these methods often lead to severe attenuation of XPS signals or localized electron beam damage. On the other hand, existing NAP-XPS studies mostly use simplified model systems (such as planar electrodes and simplified electrolyte compositions), whose structures differ significantly from real porous electrodes and complex liquid electrolyte systems containing additives. The results obtained often fail to fully reflect the interface evolution behavior of actual batteries under operating conditions, limiting the extrapolation and realism of the conclusions.

[0005] To address the aforementioned bottlenecks, there is an urgent need to develop a highly integrated in-situ electrochemical characterization platform. This platform should possess highly compatible, pollution-free battery assembly modules, interconnected transfer interfaces, and an in-situ electrochemical cell capable of operating within an XPS analysis chamber. By achieving complete isolation from air and moisture throughout the assembly, transfer, and testing processes, the platform can maintain the original state of the interfaces to the greatest extent possible, thereby enabling true in-situ monitoring of the surface and interface chemistry under battery operating conditions. The establishment of such a system is expected to closely link laboratory-level model research with actual battery systems, further revealing key interfacial processes such as the dynamic formation of mixed conductive interfaces (MCI) in solid-state batteries and the voltage-dependent polymerization behavior of liquid electrolyte additives, providing a solid scientific foundation for the interface design and regulation of next-generation high-performance rechargeable batteries. Summary of the Invention

[0006] The purpose of this invention is to provide an electrochemical in-situ characterization method and integrated system, aiming to solve the problems of interfacial composition changes caused by air exposure during traditional characterization processes of secondary batteries containing liquid electrolytes, and the difficulty in achieving in-situ monitoring under real-world operating conditions in near-ambient pressure XPS technology due to liquid evaporation and pressure limitations. This system and method can establish and maintain a controllable inert low-pressure environment, enabling air-isolated operations throughout the entire process from battery assembly to transfer to in-situ spectroscopic testing. This effectively suppresses the volatilization, decomposition, and unexpected side reactions of the liquid electrolyte, ensuring accurate capture of the original interfacial chemical processes under battery operating conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an electrochemical in-situ characterization method, the method comprising the following steps:

[0009] S1. Battery Assembly: The battery assembly is assembled in a low-pressure environment or glove box filled with an inert gas (such as argon) within a dedicated sample stage. Specifically, the working electrode and counter electrode are placed horizontally and isolated from each other within the sample stage housing. The surface of the working electrode can be pre-treated to create a smooth area, facilitating the subsequent formation of a uniform liquid electrolyte layer and reducing unnecessary attenuation of the X-ray signal. Subsequently, the liquid electrolyte is precisely applied to the surface of the working electrode and immediately covered and sealed with an encapsulation layer that allows excitation rays to penetrate and allows the generated photoelectrons to pass through, while preventing the evaporation of the liquid electrolyte, thereby forming a closed full-cell structure inside the sample stage. The encapsulation layer is located on the opposite side of the X-ray incident light path within the sample stage housing, serving simultaneously as a vacuum / pressure sealing layer and an X-ray detection window.

[0010] S2. Sample Transfer and Positioning: Under inert atmosphere conditions, the sealed full-cell sample stage is transferred to the analytical chamber of the analytical equipment (such as a near-atmospheric pressure X-ray photoelectron spectrometer) via an interconnected transfer system or a controlled atmosphere transfer chamber. A precision robotic arm or manipulator within the analytical chamber precisely fixes and positions the sample stage, ensuring that the cell's test interface region is within the detection focus of the X-ray beam and the receiving range of the electron energy analyzer. Stable mechanical fixation helps maintain the morphological stability of the electrolyte film / meniscus during testing, minimizing the impact of gravity or mechanical vibration on the film distribution.

[0011] S3. In-situ Electrochemical and Spectroscopic Testing: Inside the analytical chamber, the electrode contacts integrated on the sample stage are electrically connected to the corresponding interface of the electrochemical workstation outside the analytical chamber via a vacuum-compatible electrical feedthrough. The electrical connection components can use wires with corrosion-resistant coatings or be protected by a composite sealing structure of high-temperature ceramic and vacuum silicone to ensure performance stability under the corrosive environment of the electrolyte and maintain the airtightness of the analytical chamber. Subsequently, the electrochemical workstation applies a precise charge-discharge program to the full cell, controlling its potential or current. Simultaneously, the analytical equipment synchronously acquires X-ray photoelectron spectroscopy or other spectral signals from the battery electrode / electrolyte interface, enabling real-time, in-situ monitoring of changes in interfacial chemical composition, elemental valence states, and binding energies during the charge-discharge process.

[0012] As an optional or further optimized technical solution to the above method:

[0013] Electrical Connection and Compatibility Assurance: The working electrode and counter electrode are connected to dedicated adapters on the sample stage via integrated wires within the stage. These adapters connect to an external electrochemical workstation via a vacuum feedthrough on the analytical chamber wall (or by modifying an existing thermocouple / signal contact port within the chamber). The entire electrical connection path must ensure compatibility with a wide range of pressure conditions from ultra-high vacuum (UHV) to near-atmospheric pressure (NAP, such as 2-30 mbar), and shielding measures must be implemented to minimize electrical noise interference and ensure the synchronization accuracy of electrochemical control and spectral acquisition.

[0014] Sealing and pressure control: After the electrical feedthrough or other connecting components are installed, the feedthrough hole is finally sealed with an appropriate vacuum sealing material (such as oxygen-free copper gaskets, metal sintered seals or special epoxy resins) to ensure that no pressure leakage occurs during the transfer from an atmospheric pressure inert gas environment (such as a glove box) to a low-pressure environment (analytical chamber, etc.) and to maintain the pressure stability required for analysis.

[0015] Environmental atmosphere control: The low-pressure environment in the analysis chamber is not limited to inert gas. Reactive gases (such as O2, CO2, etc.) with a certain partial pressure can also be introduced according to experimental needs to study the evolution behavior of the battery interface under a specific atmosphere.

[0016] Secondly, the present invention provides an electrochemical integrated system for implementing the above-described method. The system includes:

[0017] 1. Dedicated Full-Battery Sample Stage: Featuring a precision-machined housing and base, this stage houses and secures a "sandwich" structure full-battery consisting of a working electrode, counter electrode, liquid electrolyte, and encapsulation layer. The stage integrates electrode leads and contacts and is compatible with transfer and analysis equipment via standardized mechanical interfaces (such as flanges or quick-lock mechanisms).

[0018] 2. Analytical equipment: Preferably, it is an X-ray photoelectron spectrometer capable of operating under near-ambient pressure conditions. Its analytical chamber is equipped with a precision sample manipulator for receiving and accurately positioning the full-cell sample stage, ensuring the reproducibility and stability of the test position.

[0019] 3. Electrochemical workstation: Used to provide precise electrochemical excitation signals (such as charge and discharge programs) and monitor the voltage and current response of the battery in real time.

[0020] 4. Interconnected Transfer System: This includes a glove box, one or more interconnected transition chambers, and corresponding robotic arms or tracks. This system is used to safely and non-destructively transfer the full-cell sample stage from one inert environment (such as a glove box) to another low-pressure or near-atmospheric-pressure inert environment (such as an analytical equipment chamber) without air contact after assembly.

[0021] As an optional or further optimization technical solution for this system:

[0022] The sample stage base is designed with a standardized interface that matches the sample rod of the XPS spectrometer or the robotic arm. It can be quickly fixed to the manipulator by screws or clips to ensure that the battery is in a horizontal and stable state, which is crucial for maintaining a uniform electrolyte layer under near-normal pressure.

[0023] The electrochemical workstation and the analytical equipment are interconnected via a synchronous trigger cable to achieve hardware-level synchronization between the charging / discharging program and the spectral acquisition, ensuring that each spectral data point has an accurate corresponding electrochemical state information.

[0024] Beneficial effects:

[0025] The electrochemical in-situ characterization method and integrated electrochemical system provided by this invention creatively achieve air-free operation from assembly to in-situ spectroscopic characterization of secondary batteries containing liquid electrolytes through a dual protection strategy combining "physical sealing of the encapsulation layer" and "inert atmosphere low-pressure environment". This method effectively overcomes the disadvantage of traditional UHV-XPS, which requires battery disassembly leading to interface changes, and also solves the bottleneck of conventional NAP-XPS, which is difficult to directly study real liquid electrolyte systems due to liquid evaporation pressure limitations.

[0026] The electrochemical integrated system of this invention integrates standardized sealed battery design, vacuum-compatible electrochemical interface, and inert atmosphere transport technology, providing a stable and reliable technical platform for real-time, in-situ study of the dynamic formation and evolution of battery interfaces (such as SEI / CEI) under pressure conditions close to actual working conditions. This not only avoids artifacts introduced by sample processing in non-in-situ analysis, but also allows direct observation of key kinetic information such as interfacial chemical bonding, intermediate product formation and transformation under voltage / current driven conditions. Therefore, it provides crucial experimental evidence for a deeper understanding of battery failure mechanisms, optimization of electrolyte formulations, and interface engineering design. Attached Figure Description

[0027] Figure 1 This is a flowchart of the electrochemical in-situ characterization method provided in the embodiments of the present invention;

[0028] Figure 2 This is a partial structural schematic diagram of the electrochemical integrated system provided in an embodiment of the present invention;

[0029] Figure 3 This is a partial structural schematic diagram of the full-cell sample stage provided in an embodiment of the present invention.

[0030] In the picture:

[0031] 1. Base; 2. Sealed housing; 21. Main housing; 22. Top cover; 221. Injection channel; 36. Working electrode wiring; 37. Counter electrode wiring; 4. Encapsulation layer; 5. Washer; 6. Working electrode conversion seat; 7. Counter electrode conversion seat; 8. Fasteners; 8a. Screw; 8b. Nut. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] like Figures 1 to 3 As shown, this embodiment provides an electrochemical integrated system, which includes a dedicated full-cell sample stage, a near-atmospheric pressure X-ray photoelectron spectrometer, an electrochemical workstation, and an interconnection and transmission system. The dedicated full-cell sample stage is used to house a full cell consisting of a working electrode, a counter electrode, a liquid electrolyte, and an encapsulation layer 4 within a sealed housing 2, and integrates vacuum-compatible electrode contacts. The analytical chamber of the near-atmospheric pressure X-ray photoelectron spectrometer is equipped with a precision manipulator for fixing and positioning the sample stage. The electrochemical workstation is used to provide electrochemical excitation and measurement. The interconnection and transmission system includes an inert atmosphere glove box for interconnecting the dedicated full-cell sample stage, the inert atmosphere glove box, and the analytical chamber of the near-atmospheric pressure X-ray photoelectron spectrometer, enabling pollution-free and atmospheric-exposure-free transfer of the sample stage.

[0037] Specifically, the dedicated full-cell sample stage includes a sample stage and a full cell placed within the sample stage. The sample stage includes a base 1 and a sealed housing 2. The sealed housing 2 includes a main housing 21 fixed to the base 1 and a top cover 22 fixed above the main housing 21. The top cover 22 and the main housing 21 are fixed to the base 1 by four screws. The top cover 22 has a central through-hole injection channel 221, and its side facing the main housing 21 is used to position the encapsulation layer 4 of the full cell. The encapsulation layer 4 is one or more of a polymer film, a low-dimensional layered material, a metal-organic framework film, or an inorganic ceramic film.

[0038] The electrochemical sample stage also includes a gasket 5, a working electrode conversion seat 6, and a counter electrode conversion seat 7. The working electrode conversion seat 6 is fixed to the base 1, and a gasket 5 is provided between the working electrode conversion seat 6 and the base 1. The counter electrode conversion seat 7 is stacked and fixed on the working electrode conversion seat 6, and a gasket 5 is provided between the counter electrode conversion seat 7 and the working electrode conversion seat 6. The gasket 5 effectively prevents direct contact between the base 1, the working electrode conversion seat 6, and the counter electrode conversion seat 7, preventing accidental discharge or grounding.

[0039] One end of the counter electrode wiring 37 passes tightly through the sealed housing 2 and is connected to the counter electrode of the full battery, while the other end of the counter electrode wiring 37 is connected to the counter electrode conversion seat 7. One end of the working electrode wiring 36 passes tightly through the sealed housing 2 and is connected to the working electrode of the full battery, while the other end of the working electrode wiring 36 is connected to the working electrode conversion seat 6.

[0040] The main housing 21 has two wiring holes corresponding to the working electrode wiring 36 and the counter electrode wiring 37, respectively. The working electrode wiring 36 and the counter electrode wiring 37 are tightly embedded in the corresponding wiring holes to ensure that there is no leakage of gas or liquid under vacuum conditions. When the wiring is inserted into the corresponding wiring hole and the electrode lines are connected, the liquid electrolyte will not leak out of the main housing 21.

[0041] In this embodiment, the working electrode conversion seat 6, the counter electrode conversion seat 7, and the washer 5 are fixed to the base 1 by fasteners 8. Three washers 5 are provided. The fasteners 8 consist of screws 8a and nuts 8b. Screw 8a passes through the base 1. The first washer 5, working electrode conversion seat 6, second washer 5, counter electrode conversion seat 7, and third washer 5 are sequentially stacked and fitted over screw 8a, and locked by nuts 8b. Both screws 8a and nuts 8b are made of insulating material, such as polytetrafluoroethylene (PTFE), to prevent short circuits / grounding caused by electronic contact between different circuits. The working electrode conversion seat 6 and the counter electrode conversion seat 7 are used to interface with the spring probe or vacuum feedthrough socket on the spectrometer sample stage to extract electrical signals.

[0042] The near-atmospheric pressure X-ray photoelectron spectroscopy (NAP-XPS) analyzer is equipped with a multi-axis precision sample manipulator, an ion etching gun, and a differential pumping system.

[0043] The interconnected transmission system includes a high-purity inert atmosphere glove box, one or more interconnected transition chambers, and corresponding transmission mechanisms, used to achieve contamination-free transfer of the sample stage between different chambers.

[0044] The innovation of this system lies in its modularization and standardization of electrochemical cells, and its deep integration with a high-end surface analysis platform through interconnection technology, forming a closed and controllable in-situ research environment, providing a powerful experimental tool for secondary battery interface science.

[0045] This embodiment also provides an in-situ electrochemical characterization method, which aims to achieve in-situ, real-time chemical analysis of the electrode / electrolyte interface of a secondary battery containing a liquid electrolyte under operating conditions. The core of this method lies in constructing an inert atmosphere environment that isolates the entire process from air, and seamlessly integrating battery assembly, transport, and near-atmospheric pressure spectroscopic analysis through a standardized, vacuum-compatible battery design and transfer system. Specifically, it includes the following steps:

[0046] Step S1: In an inert atmosphere, assemble a battery structure containing a working electrode and a counter electrode in the sample stage; apply liquid electrolyte to the working electrode and seal it with an encapsulation layer that has high X-ray transmittance to form a sealed full cell, thereby obtaining a sample stage that integrates the full cell.

[0047] S1.1 Construction and Control of the Inert Atmosphere Environment: Before the experiment, the entire system (including the glove box and other inert environment chambers, the vacuum transfer chamber, and the analytical equipment chamber) was pre-purified with high-purity inert gas through multiple purging and pressurization processes to create a stable, clean, low-water-oxygen environment. This environment is the basis for all subsequent operations. The pressure within the analytical chamber was maintained in the near-atmospheric pressure range of 2-30 mbar, and the inert atmosphere consisted of an inert gas or a reactive gas in a controllable proportion.

[0048] S1.2 Fine surface processing of the working electrode: To obtain a uniform and smooth electrode surface to facilitate the formation of a stable liquid electrolyte thin layer and optimize the X-ray detection signal, the surface of the working electrode needs to be pre-treated before assembling the battery structure to form a smooth region with a roughness of less than 50 nm, which is used to support the liquid electrolyte and the encapsulation layer. The pre-treatment is a surface planarization process.

[0049] In this embodiment, the working electrode is a three-dimensional electrode loaded with active material. The smooth region of the working electrode is used to support the liquid electrolyte and the encapsulation layer 4. Surface smoothing treatment can be performed by focused ion beam (FIB) or helium ion beam processing, etc. The "smooth region" refers to a nanoscale smooth and flat area on the surface of the working electrode, with extremely low roughness, approaching the effect of an optical mirror, which is very suitable for uniform electrolyte distribution and contact with the encapsulation layer 4. The working electrode is placed in a surface processing or pretreatment equipment (such as focused ion beam equipment, plasma cleaner, etc.) connected to the system under inert environmental protection. Ion beam polishing technology is used to gradually optimize the surface smoothness of the electrode through a multi-step process, preparing a microscale smooth region with appropriate roughness in the active material region of the electrode. This step can significantly reduce the gap between the subsequent encapsulation layer and the electrode surface, reduce the scattering attenuation of photoelectron signals, and improve the detection sensitivity of the buried interface. Optionally, to reduce ion contamination, helium ion microscopy (HIM) or low-energy argon cluster beam can be used for surface polishing.

[0050] S1.3 Full Cell Packaging and Sample Stage Integration: Under inert conditions, the working electrode and counter electrode (and / or reference electrode), after surface planarization, are horizontally stacked and separated from adjacent electrodes by a diaphragm or insulating gasket within the sealed housing of a dedicated sample stage. Liquid electrolyte is precisely dripped onto the smooth area of ​​the working electrode using a micro-syringe. Immediately afterwards, a thin film with high X-ray transmittance is used as an encapsulation layer to cover the liquid electrolyte. The surface tension of the film and the sealing structure on the sealed housing form a physical seal, thus creating a closed "sandwich" structure full cell. The encapsulation layer faces the pre-designed X-ray entrance window on the sample stage's sealed housing. The entire sample stage's sealed housing is designed as a vacuum-sealed structure, ensuring airtightness during subsequent transfer and under different pressure environments through O-rings or metal gaskets.

[0051] Step S2: Transfer the sample stage to the analysis chamber of the near-atmospheric pressure X-ray photoelectron spectrometer via interconnection and transmission while maintaining an inert atmosphere. Use the manipulator in the analysis chamber to position the sample stage so that the interface of the full cell to be measured is within the X-ray detection range of the near-atmospheric pressure X-ray photoelectron spectrometer.

[0052] The assembled full-cell sample stage is transferred directly from the glove box environment to the analysis chamber of the near-atmospheric-pressure X-ray photoelectron spectrometer via interconnected transmission, without contact with the atmosphere. During the transfer, the system pressure can be gradually adjusted according to the program under the protection of an inert atmosphere to avoid sudden pressure changes that could impact the encapsulation layer.

[0053] Optionally, after transferring the sample stage to the analysis chamber, the stage is adjusted to a horizontal and stable position using a manipulator to minimize the influence of gravity on the distribution of the liquid electrolyte. Specifically, after entering the analysis chamber, the sample stage is precisely fixed and positioned using a precision multi-axis sample manipulator within the chamber. The manipulator is adjusted so that the area of ​​the battery to be tested on the sample stage (i.e., the electrode / electrolyte interface under the sealing layer) is precisely within the detection range of the X-ray source, i.e., within the focal point of the X-ray source and the receiving cone angle of the electron energy analyzer. To ensure the stability of the liquid electrolyte distribution, the sample stage is typically adjusted to a horizontal position to minimize the influence of gravity on the liquid film / meniscus morphology.

[0054] Step S3: Connect the electrode contacts integrated on the sample stage to the electrochemical workstation outside the analysis chamber via a vacuum-compatible electrical connection; the electrochemical workstation controls the charging and discharging of the full cell, and simultaneously drives the near-ambient pressure X-ray photoelectron spectrometer to synchronously collect photoelectron spectra from the interface to be tested, thereby performing in-situ characterization of the dynamic changes in the chemical composition of the working electrode-liquid electrolyte interface during the charging and discharging process.

[0055] S3.1 Electrical Connection and Compatibility Assurance: Inside the analytical chamber, the electrode contacts (working electrode and counter electrode contacts) integrated on the sample stage are connected to the vacuum feedthrough connectors on the chamber wall. These feedthroughs lead the electrical signals to the electrochemical workstation outside the chamber. The sample stage integrates mutually insulated working electrode and counter electrode conversion seats, which are connected to the working electrode and counter electrode respectively via wires. The working electrode and counter electrode conversion seats are connected to the external electrochemical workstation via the vacuum feedthroughs on the analytical chamber wall or via a pre-set electrical signal transmission interface on the analytical chamber. This ensures long-term stability and low leakage rate (typically required <10%) in low-pressure to near-ambient-pressure environments and in the presence of liquid electrolyte vapors. -6 mbar·L / s).

[0056] Taking a dedicated full-cell sample stage as an example, the wiring includes a working electrode connector 36 and a counter electrode connector 37. The working electrode is connected to the working electrode conversion seat 6 of the sample stage via the working electrode connector 36, and the counter electrode is connected to the counter electrode conversion seat 7 of the sample stage via the counter electrode connector 37. The working electrode conversion seat 6 and the counter electrode conversion seat 7 are electrically connected to the corresponding interface of the electrochemical workstation via a vacuum power feedthrough or a preset electrical signal transmission interface of the energy dispersive spectrometer (such as a thermocouple contact wire). The vacuum power feedthrough refers to a vacuum-compatible multi-channel electrical lead used to lead the battery electrode signal from inside the NAP-XPS analysis chamber to an external electrochemical workstation.

[0057] In this embodiment, the existing thermocouple contact wires or vacuum feeders on the energy dispersive spectrometer sample stage are used as the positive / negative current leads. The pre-designed electrical signal transmission interface is equipped with a PTFE or gold-plated corrosion-resistant layer, or a ceramic and vacuum silicone composite sealing structure for sheathing. The corrosion-resistant layer wraps around the transmission interface contact wires; it effectively isolates corrosive media, protects the transmission interface contact wires from corrosion, and extends their service life. If a high-temperature ceramic tube and vacuum silicone sealing structure is used, the high-temperature ceramic tube provides rigid protection, while the vacuum silicone provides flexible sealing, significantly improving the performance of the transmission interface contact wires in high-temperature, corrosive, or low-pressure environments. A corresponding corrosion-resistant layer or sealing structure can also be provided outside the conductors.

[0058] Optionally, one or two vacuum-compatible copper wires are connected in parallel with the transmission interface contact wire to achieve a charging and discharging current of >50mA; the transmission interface contact wire and the vacuum-compatible copper wire pass through the same feedthrough hole of the energy dispersive spectrometer.

[0059] If a vacuum electric feedthrough connection is used, the vacuum electric feedthrough must be fixed through and fixed to the feedthrough hole of the energy dispersive spectrometer, and then the feedthrough hole should be filled with sealing material; the sealing material is vapor pressure vacuum grease or UV adhesive. Use low vapor pressure vacuum grease or UV adhesive to fill the feedthrough hole, ensuring <10 -6 Low leakage rate (mbar·L / s).

[0060] S3.2 Controllable Encapsulation Layer Thinning and Interface Exposure: To optimize XPS signal intensity and approximate the actual liquid-solid interface as closely as possible, the encapsulation layer can be controlled and thinned in situ before spectral acquisition. The inert gas ion gun (e.g., Ar⁺) or cluster ion source integrated within the analysis chamber is activated to perform low-speed, controllable layer-by-layer sputtering etching on the central region of the encapsulation layer. During this process, broadband XPS scans can be acquired simultaneously to monitor changes in the signal intensity of specific elements. When the characteristic XPS signal intensity from the liquid electrolyte reaches its maximum value and tends to a stable plateau, it indicates that the etching has approached the interface between the encapsulation layer and the liquid electrolyte. Etching should be stopped immediately to avoid over-etching and damaging the underlying liquid electrolyte or electrodes. The ion source used for etching can be argon ions, gas cluster ion beams, synchrotron soft X-rays, or electron beams.

[0061] In this embodiment, in-situ layer-by-layer etching is used to thin the encapsulation layer 4. The change in the intensity of the characteristic XPS signal from the liquid electrolyte is monitored as feedback to determine the thinning progress. Thinning is stopped when the signal intensity stabilizes to avoid artifacts such as electrolyte decomposition that may be caused by over-etching. At this point, the thickness of the thinned encapsulation layer 4 is sufficient to allow photoelectrons to escape while preventing the liquid electrolyte from evaporating. During the etching process, this technique selectively thins the encapsulation layer 4 material without penetrating the encapsulation layer or causing liquid leakage.

[0062] S3.3 Pressure Equilibrium and Electrochemical Testing: After etching, a trace amount of high-purity inert gas or liquid electrolyte saturated vapor can be backfilled into the analysis chamber to stabilize the chamber pressure within the optimal operating range of NAP-XPS, thereby balancing the pressure difference, stabilizing the interface, and maintaining sufficient electron mean free path.

[0063] S3.4 In-situ Electrochemical-Spectroscopic Synchronous Acquisition: Set the charge / discharge program of the electrochemical workstation (e.g., constant current charge / discharge, cyclic voltammetry, etc.) and start the program. Through hardware trigger lines or software synchronization, ensure complete synchronization between the electrochemical workstation and the XPS spectrometer. While the battery is undergoing charge / discharge cycles, the XPS system continuously acquires high-resolution spectra of the target elements at preset time or potential intervals. By analyzing the dynamic changes in the binding energy shift, peak shape, and relative intensity of specific elements (e.g., C 1s, O 1s, F 1s, Li 1s, etc.), key information such as the evolution of the chemical composition of the electrode-electrolyte interface phase, the formation and consumption of reaction intermediates, and real-time changes in interfacial potential can be revealed in situ.

[0064] The electrochemical in-situ characterization method provided in this embodiment deeply integrates "in-situ sealing technology of encapsulation layer", "contamination-free transmission in a fully inert atmosphere" and "controllable interface exposure and synchronous measurement technology", which realizes accurate and dynamic observation of the interface chemical process of real liquid electrolyte battery system under working conditions, and effectively avoids the sample distortion problem caused by traditional non-in-situ characterization.

[0065] 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. An electrochemical in-situ characterization method, characterized in that, Includes the following steps: In an inert atmosphere-protected environment, a battery structure containing a working electrode and a counter electrode is assembled in a sample stage; a liquid electrolyte is applied to the working electrode and sealed with an encapsulation layer that has high X-ray transmittance to form a sealed full cell, thereby obtaining a sample stage that integrates the full cell. The sample stage is transferred to the analysis chamber of the near-atmospheric pressure X-ray photoelectron spectrometer under the condition of maintaining an inert atmosphere via an interconnected transmission system. The sample stage is then positioned using a manipulator in the analysis chamber so that the test interface of the full cell is within the X-ray detection range of the near-atmospheric pressure X-ray photoelectron spectrometer. The electrode contacts integrated on the sample stage are connected to the electrochemical workstation outside the analysis chamber via a vacuum-compatible electrical connection. The electrochemical workstation controls the charging and discharging of the full cell and simultaneously drives the near-ambient pressure X-ray photoelectron spectrometer to synchronously acquire photoelectron spectra from the interface under test, thereby performing in-situ characterization of the dynamic changes in the chemical composition of the working electrode-liquid electrolyte interface during the charging and discharging process.

2. The electrochemical in-situ characterization method according to claim 1, characterized in that, After transferring the sample stage to the analysis chamber, the sample stage is adjusted to a horizontal and stable position using the manipulator to minimize the influence of gravity on the distribution of the liquid electrolyte.

3. The electrochemical in-situ characterization method according to claim 1, characterized in that, When assembling the battery structure, the working electrode and the counter electrode are horizontally stacked and isolated by an insulating component, and then placed inside the sealed housing of the sample stage; the encapsulation layer covers the working electrode on which the liquid electrolyte has been applied, and its position is directly opposite the X-ray incident window opened on the sealed housing.

4. The electrochemical in-situ characterization method according to claim 3, characterized in that, The sample stage integrates a working electrode conversion seat and a counter electrode conversion seat that are insulated from each other, and the working electrode and the counter electrode are respectively connected by wires; the working electrode conversion seat and the counter electrode conversion seat are connected to an external electrochemical workstation through a vacuum feedthrough on the wall of the analysis chamber or through a preset electrical signal transmission interface on the analysis chamber.

5. The electrochemical in-situ characterization method according to claim 4, characterized in that, The wires used for electrical connection or the preset electrical signal transmission interface are protected by a polytetrafluoroethylene or gold-plated corrosion-resistant layer, or by a sealing structure composed of ceramic and vacuum silicone.

6. The electrochemical in-situ characterization method according to claim 1, characterized in that, Before assembling the battery structure, the surface of the working electrode is pretreated to form a smooth area for supporting the liquid electrolyte and the encapsulation layer. The surface roughness Ra of the smooth region is less than 50 nm, preferably less than 10 nm; The liquid electrolyte is applied to the smooth area and then sealed with the encapsulation layer.

7. The electrochemical in-situ characterization method according to claim 1, characterized in that, Before spectral acquisition, the encapsulation layer is thinned in a controlled in-situ etching process using an ion source integrated within the analysis chamber until the intensity of the characteristic XPS signal from the liquid electrolyte stabilizes.

8. The method according to claim 7, characterized in that, Before the controllable in-situ etching and thinning, the sample stage is placed horizontally and stably in the analysis chamber.

9. The electrochemical in-situ characterization method according to claim 1, characterized in that, The pressure inside the analysis chamber is maintained in the near-normal pressure range of 2-30 mbar, and the inert atmosphere is an inert gas or a reactive gas in a controllable proportion.

10. An electrochemical integrated system, characterized in that, For implementing the electrochemical in-situ characterization method as described in any one of claims 1-8, comprising: A dedicated full-cell sample stage is used to house a full cell consisting of a working electrode, a counter electrode, a liquid electrolyte, and an encapsulation layer (4) within a sealed housing (2), and integrates vacuum-compatible electrode contacts. A near-atmospheric pressure X-ray photoelectron spectrometer, the analysis chamber of which is equipped with a precision manipulator for fixing and positioning the sample stage; An electrochemical workstation is used to provide electrochemical excitation and measurement. The interconnected transmission system includes an inert atmosphere glove box, and the dedicated full-cell sample stage, the inert atmosphere glove box, and the analysis chamber of the near-atmospheric pressure X-ray photoelectron spectrometer are interconnected to achieve pollution-free and atmospheric-free transfer of the sample stage.

11. The electrochemical integrated system according to claim 10, characterized in that, The sample stage is fixed to the manipulator of the near-atmospheric pressure X-ray photoelectron spectrometer via a mechanical interface; the base (1) of the sample stage is provided with an insulated working electrode conversion seat (6) and a counter electrode conversion seat (7) for connecting to an external circuit via a spring probe or a vacuum feed socket.

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