Gas-phase reaction cell suitable for in-situ high-temperature electrochemical Raman experiments and its usage method

Abstract

This invention provides a gas-phase reaction cell and its usage method for in-situ high-temperature electrochemical Raman experiments. The cell includes a reaction cell body, a sample stage and heating assembly, a water-cooling assembly, and an electrical interface assembly. The sample stage and heating assembly are installed inside the reaction cell body. The water-cooling assembly is fixed to the lower end face of the reaction cell body. The electrical interface assembly is connected via an electrical interface flange on the side wall of the reaction cell body. This invention addresses two different problems: studying the surface of gas-solid reactions and studying solid-phase changes during the reaction process. It employs two different operating modes to control the environment (temperature and pressure), enabling in-situ monitoring of gas-solid phase electrochemical reactions in conjunction with a Raman spectrometer.

Description

Technical Field

[0001] This invention belongs to the field of in-situ experimental technology, specifically relating to a gas-phase reaction cell and its usage method that can be used for in-situ high-temperature electrochemical Raman experiments. Background Technology

[0002] Fuel cells are considered one of the most promising new clean energy materials, and solid oxide fuel cells are a widely used example. The performance and lifespan of fuel cells are key indicators of interest to researchers, as they depend not only on the reactions at the anode and cathode but also on the properties of the electrode and electrolyte materials themselves. Designing novel electrocatalysts to complement different types of cells can significantly improve various performance metrics.

[0003] To gain a clearer understanding of solid-phase materials and interface structures, in-situ characterization is necessary. Electrochemistry is a commonly used characterization method in battery research, measuring the performance and kinetic processes of battery components (electrodes and electrolytes) in real time. However, its limitation is that it cannot monitor the physical or chemical information involved in the process. Raman spectroscopy, on the other hand, can monitor changes in the chemical composition of a sample in real time without damaging the sample. In-situ experiments combining electrochemistry and Raman spectroscopy have gradually become an important research method for analyzing battery materials and interfacial reactions (including electrode reactions and catalyst-mediated activation) in fuel cells.

[0004] The electrode reactions in solid oxide fuel cells involve the mixing of gaseous fluids and solid phases. Gas-solid reactions are among the most complex chemical reactions, and factors influencing chemical reactions involving gaseous fluids include, but are not limited to, the types and proportions of the reacting gases, as well as the influence of the external environment, such as temperature and pressure. However, almost no device can simultaneously perform in-situ spectroscopic electrochemical techniques for gas-solid phase electrochemical reactions under high temperature and high pressure.

[0005] In addition, one of the most widely used chemical reactions in industry is gas-solid phase catalytic reaction. Under certain temperature and pressure, gaseous fluid components react under the action of solid catalyst. This is also a gas-solid phase reaction. In order to obtain highly efficient catalysts with high catalytic activity and anti-poisoning performance, in-situ spectroscopic electrochemical characterization of gas-solid phase catalytic reaction under high temperature and high pressure is also required.

[0006] When performing in-situ characterization of gas-solid reactions or gas-solid phase catalytic reactions, it is also necessary to consider that the focus of studying the gas-solid interface and the changes in solid materials during the reaction process are different. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a gas-phase reaction cell and its usage method for in-situ high-temperature electrochemical Raman experiments, taking into account the environmental requirements of in-situ gas-solid phase reactions. It provides unique usage methods for characterizing different problems in gas-solid reactions, which is helpful for research in fields such as energy storage materials, novel batteries, and gas-solid catalysis.

[0008] This invention utilizes a small-volume cavity to reduce the dead volume of the gas-solid phase reaction, easily achieving good airtightness and dynamically exchanging the gaseous fluid within the cavity, thereby controlling and monitoring pressure factors during the reaction process. The gaseous fluid can be a gas mixture (a mixture of several different gases in a certain proportion) or a pure gaseous substance.

[0009] A ceramic heater is used to heat the sample platform, thereby controlling and monitoring the temperature factors during the reaction process. This clean heating method does not affect the reaction being observed, and the special material platform is in close contact with the sample, ensuring uniform heating.

[0010] Temperature control is considered in the design of the device: the sample stage is fixed to the bottom of the reaction chamber only by copper studs and does not contact the side wall. With the dynamic gas flow, the temperature of the side wall of the reaction chamber is reduced; while the bottom of the reaction chamber is equipped with a water cooling component to dissipate heat from the reaction chamber while avoiding burns to the characterization platform or personnel.

[0011] To address two different problems—studying gas-solid reaction surfaces and studying solid-phase changes during the reaction—two different operating modes are employed to control the environment (temperature and pressure), combined with Raman spectroscopy to achieve in-situ monitoring of gas-solid phase electrochemical reactions. This in-situ characterization technique is applicable not only to gas-solid phase reactions but also to gas-phase fluid reactions occurring on solid-phase catalytic surfaces.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments includes a reaction cell body, a sample stage and heating components, a water-cooling component and an electrical interface component.

[0014] The sample stage and heating components are installed inside the reaction tank body. The water cooling components are fixed to the lower end face of the reaction tank body. The electrical interface components are connected through the electrical interface flange on the side wall of the reaction tank body.

[0015] The main body of the reaction cell includes a window top cover, a light-transmitting window, a rectangular sealing ring, a reaction cell top cover, an O-ring sealing ring, window precision screws, cavity fastening screws, a reaction cell cavity, a gas phase fluid inlet interface, a gas phase fluid outlet interface, and an electrical interface;

[0016] The top cover of the window, the light-transmitting window, and the top cover of the reaction tank are concentrically assembled. The top cover of the window is fixed to the top cover of the reaction tank by precision screws. A rectangular sealing ring is placed in a rectangular groove on the outside of the top cover of the reaction tank to prevent optical errors caused by deformation and damage due to uneven stress after the light-transmitting window is assembled. An O-ring is placed in a rectangular groove on the inside of the top cover of the reaction tank. The cavity fastening screws press the top cover of the reaction tank against the O-ring, fixing it to the reaction tank cavity and maintaining the internal pressure of the cavity. The gas phase fluid inlet, gas phase fluid outlet, and electrical interface are welded to the outer surface of the reaction tank cavity. The gas inside the cavity exchanges gas through the gas phase fluid inlet and outlet. The gas phase fluid inlet and outlet are symmetrically arranged relative to the electrical interface. The precision screws of the window and the cavity fastening screws are evenly distributed on the top cover of the window and the top cover of the reaction tank. The electrical wiring of the sensors and heaters inside the cavity is connected out through the electrical interface.

[0017] The sample stage and heating assembly consist of electrodes, a carrying platform, a heater, a support platform, conductive screws, support fastening screws, washers, and studs. The sample is clamped and fixed to the carrying platform by the electrodes, and the conductive screws fix the carrying platform to the support platform while clamping the heater. The support fastening screws, along with the washers, are connected to the studs under the support platform, and the studs are installed inside the reaction chamber.

[0018] The water-cooling assembly includes an upper cover, a lower cover, cooling pipes, water-cooling fastening screws, and overall connecting screws. The cooling pipes are placed inside the lower cover, and the water-cooling fastening screws fix the upper cover and the lower cover to form a module. The overall connecting screws connect the water-cooling assembly to the main body of the reaction tank.

[0019] The electrical interface assembly includes a tee pipe, a thermocouple connector, and a feedthrough connector; the tee pipe connects to the electrical interface, the thermocouple connector, and the feedthrough connector, respectively. Electrical wiring for electrodes and heaters within the reaction chamber is led out through the electrical interface and connected to the thermocouple connector and the feedthrough connector, respectively, for external connection to circuitry or a controller.

[0020] This invention also provides a method for using a gas-phase reaction cell that can be used in in-situ high-temperature electrochemical Raman experiments, including methods for controlling and monitoring the temperature and pressure inside the cell:

[0021] The ceramic heater heats the platform, indirectly transferring heat to the solid sample. External control voltage input, via a feedthrough connector, regulates the temperature input of the heating element. The ceramic heater provides thermocouple terminals; wires connect to the positive and negative pins of the thermocouple connector, allowing for external temperature measurement near the solid sample. For accurate solid sample surface temperature measurement, two wires are directly fixed to the sample surface via electrodes and connected to the positive and negative pins. To prevent overheating at the bottom of the reaction tank from scalding the characterization platform, a water-cooling system is installed at the bottom. A pump in the circulating water tank circulates deionized water, cooling the platform.

[0022] The switch valve on the gas cylinder controls the opening and closing of the gas phase fluid inlet. The gas mass flow controller is set to a closed-loop pressure control mode with flow monitoring to dynamically change the pressure of the gas phase fluid in the chamber. The gas phase fluid in the chamber is then discharged through the valve to the safety gas cabinet for processing.

[0023] Beneficial effects:

[0024] (1) This invention provides a device for gas-solid phase chemical reactions that has good airtightness, dynamic gas flow, adjustable reaction environment (temperature and pressure inside the chamber), and modular structure for easy installation and disassembly, while also performing in-situ characterization of electrochemistry and Raman spectroscopy; providing a reliable experimental platform for scientific research such as solid fuel cells and heterogeneous catalysis.

[0025] (2) In order to accurately reproduce the reaction process of gas-solid phase chemical reaction, it is necessary to monitor and control the reaction environment such as temperature and pressure.

[0026] The boron nitride platform is heated by a ceramic heater to ensure uniform heating of the sample. This heating method is safer and cleaner than resistance wire heating and laser heating. Resistance wires are typically made of metal or alloy materials, which can interfere with the catalytic reaction process of gas-phase fluids. Laser heating is attenuated by the gas before contacting the solid sample surface, reducing heating efficiency. The sample temperature is indirectly monitored by thermocouples in the ceramic heater, or the wires can be fixed to the sample surface via electrodes to directly monitor the sample surface temperature.

[0027] The pressure inside the reaction tank can be connected to an adjustable pressure gas cylinder via a gas inlet / outlet interface. At the same time, the high-strength material and airtight reaction tank cavity ensure high-temperature and high-pressure reaction conditions, thereby achieving the purpose of controlling and monitoring the reaction pressure inside the cavity.

[0028] Heaters, thermocouples, and other internal electrical components can be connected through electrically sealed interfaces to ensure the stability of the gas-tight reaction environment.

[0029] (3) The temperature of the device is controlled by the design of the present invention. The reaction platform of the gas-solid phase sample does not contact the side wall of the reaction cell. Copper studs are used to separate the reaction platform from the bottom of the reaction cell. In addition, the gas exchange interface near the side wall of the reaction cell carries away some heat due to the flow of gas, which greatly reduces the temperature of the side wall of the reaction cell. The hottest part of the metal shell should be at the bottom of the reaction cell. A water-cooling component is set at the bottom of the reaction device, which reduces the temperature of the outer shell of the reaction cell and ensures that the Raman spectrometer is not damaged during installation.

[0030] (4) The sample is made into a thin plate and fixed on the boron nitride stage by a pressing electrode. The purpose of this fixing method is as follows:

[0031] The sample is bonded to the boron nitride stage, ensuring uniform heating. Compared to clamping the sample with electrodes at both ends, this design is less likely to cause brittle sample breakage and is unaffected by convection during gas exchange. The pellet electrode is adjustable to accommodate the sample thickness, and since Raman spectroscopy is surface-sensitive, the sample thickness should not be too thick. The boron nitride stage is insulated and will not interfere with the sample during electrochemical testing.

[0032] (5) This invention has the following two working modes for different research problems:

[0033] In the conventional mode, the solid phase is fixed on the carrier platform, and the carrier platform is heated by a ceramic heater to transfer heat to the solid phase. During the reaction, the gas phase fluid is constantly flowing in and out, which can be used to control the proportion of gas phase fluid components in the chamber, and the pressure in the chamber can also be controlled externally. As the gas flows in and out, water cooling circulation occurs simultaneously, and the temperature of the solid phase is relatively higher than that of the gas phase fluid. This mode is suitable for studying the changes of solid phase materials in gas-solid reactions or studying the changes of solid phase catalysts that assist gas phase fluid reactions.

[0034] In high-temperature mode, to ensure airtightness within the chamber, the sealing rings at the top of the window and the top of the reaction tank were replaced with pure gold sealing rings before the experiment. Water cooling circulation was shut off to prevent heat loss. The solid phase was fixed on the platform. Initially, a certain proportion of gaseous fluid was introduced, and then the inlet and outlet valves for the gaseous fluid were closed. Heat transfer was achieved through a ceramic heater, heating the platform in contact with the solid phase. The temperature of the gaseous fluid continuously increased through radiation and convection between the solid phase and the platform, until the solid phase and gaseous fluid temperatures became similar. This mode is suitable for studying surface reaction processes in gas-solid reactions or gaseous fluid reactions on the surface of solid catalysts.

[0035] For gas-solid phase chemical reactions, this invention provides a device with good airtightness, dynamic gas flowability, adjustable reaction environment (temperature, pressure, etc.), and modular structure for easy installation and disassembly, while simultaneously performing in-situ electrochemical and Raman spectroscopy characterization. Attached Figure Description

[0036] Figure 1 The illustration shows the main components of the gas-phase reaction cell of the present invention, which can be used for in-situ high-temperature electrochemical Raman experiments;

[0037] Figure 2 The illustration shows the main components of the gas-phase reaction cell body that can be used for in-situ high-temperature electrochemical Raman experiments according to the present invention;

[0038] Figure 3 This is a schematic diagram of the top cover of the window; where Figure (a) is a sectional view and Figure (b) is a top view;

[0039] Figure 4 This is a schematic diagram of the top cover of the reaction tank; where Figure (a) is a top view and Figure (b) is a bottom view.

[0040] Figure 5 Figure 1 is a schematic diagram of the reaction chamber; where Figure (a) is a front view, Figure (b) is an axonometric view, Figure (c) is a bottom view, and Figure (d) is a top view.

[0041] Figure 6 Illustrations of the main components of the sample stage and heating assembly;

[0042] Figure 7 This is a schematic diagram of the support platform; where Figure (a) is a top view and Figure (b) is an axonometric view.

[0043] Figure 8 Illustration of the main components of the water-cooling assembly;

[0044] Figure 9 This is a top view of the bottom cover;

[0045] Figure 10 Diagram of the main components of the electrical interface assembly;

[0046] Figure 11 This is a diagram showing the overall connection between the system and the external environment. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] This invention proposes a gas-phase reaction cell that can be used for in-situ high-temperature electrochemical Raman experiments, such as... Figure 1 As shown, it includes a reaction tank body 1, a sample stage and heating assembly 2, a water cooling assembly 3, and an electrical interface assembly 4.

[0049] The sample stage and heating assembly 2 are installed inside the reaction tank body 1. The water cooling assembly 3 is fixed to the lower end face of the reaction tank body 1. The electrical interface assembly 4 is connected through the electrical interface flange on the side wall of the reaction tank body 1.

[0050] like Figure 2 As shown, the main body 1 of the reaction tank mainly includes a window top cover 1-1, a light-transmitting window 1-2, a rectangular sealing ring 1-3, a reaction tank top cover 1-4, an O-ring sealing ring 1-5, a window precision screw 1-6, a cavity fastening screw 1-7, a reaction tank cavity 1-8, a gas phase fluid inlet port 1-9, a gas phase fluid outlet port 1-10, and an electrical interface 1-11.

[0051] The top cover 1-1 of the window and the light-transmitting window 1-2 are concentrically assembled with the top cover 1-4 of the reaction tank. The top cover 1-1 of the window is fixed to the top cover 1-4 of the reaction tank by window precision screws 1-6. A rectangular sealing ring 1-3 is placed in a rectangular groove on the outside of the top cover 1-4 of the reaction tank to prevent optical errors caused by deformation and damage due to uneven stress after the light-transmitting window 1-2 is assembled. An O-ring 1-5 is placed in a rectangular groove on the inside of the top cover 1-4 of the reaction tank. The cavity fastening screws 1-7 press the top cover 1-4 of the reaction tank against the O-ring 1-5, fixing it to the cavity 1-8 of the reaction tank, maintaining the internal pressure of the cavity. A gas phase fluid inlet port 1-9, a gas phase fluid outlet port 1-10, and an electrical interface 1-11 are welded to the outer surface of the cavity 1-8 of the reaction tank. The gas phase fluid in the cavity exchanges fluid through convection between the gas phase fluid inlet port 1-9 and the gas phase fluid outlet port 1-10. The gas phase fluid inlet port 1-9 and the gas phase fluid outlet port 1-10 are symmetrically arranged relative to the electrical interface 1-11. To ensure that the light transmission window 1-2 and the reaction tank top cover 1-4 are subjected to uniform stress under the gas pressure inside the cavity, the window precision screws 1-6 and the cavity fastening screws 1-7 are evenly distributed on the window top cover 1-1 and the reaction tank top cover 1-4, respectively. The electrical wiring of the sensors and heaters inside the cavity is connected out through the electrical interface 1-11.

[0052] The window top cover 1-1 is a thick cover with a central cylindrical hole, made of 316L stainless steel. Figure 3 As shown, the lower surface is a fixed surface. To ensure good airtightness, it needs to be polished. Its function is to fix the light transmission windows 1-2, introduce incident light into the reaction tank system, and extract out the outgoing light.

[0053] The light-transmitting windows 1-2 are cylindrical planar lenses made of silicon dioxide with a thickness of 2cm. Their function is to provide good transmittance for incident and outgoing light and to shield impurities from interfering with the reaction inside the reaction tank.

[0054] The rectangular sealing ring 1-3 has a rectangular cross-section and is made of polyimide. Its function is to seal the light transmission window 1-2 with the top cover 1-4 of the reaction tank, preventing gaps from appearing when the light transmission window 1-2 is fixed, which would affect the airtightness of the reaction tank.

[0055] The reaction tank top cover 1-4 is made of 316L stainless steel. The upper surface has a stepped surface that requires polishing for precision installation of the window top cover 1-1. A rectangular groove is provided for the rectangular sealing ring 1-3. The lower surface is flat and has a rectangular groove for the O-ring sealing ring 1-5. Figure 4 As shown.

[0056] The O-ring 1-5 has an O-shaped cross section and is made of polyimide. Its function is to seal the reaction tank top cover 1-4 and the reaction tank cavity 1-8, preventing gaps from appearing when the reaction tank top cover 1-4 is fixed, which would affect the airtightness of the reaction tank.

[0057] The precision screws 1-6 for the window are made of 316L stainless steel, numbered four in total, with small diameter and short lead. Their function is to fix the light-transmitting window 1-2 to the top cover 1-4 of the reaction tank. Under the pressure difference between the inside and outside of the reaction tank, the light-transmitting window 1-2 bears a large pressure per unit area.

[0058] The cavity fastening screws 1-7 are made of 316L stainless steel, and there are 6 of them. Their function is to fix the top cover 1-4 of the reaction tank to the cavity 1-8 of the reaction tank. This ensures good airtightness of the device and a stable experimental environment under the pressure difference between the inside and outside of the reaction tank.

[0059] The reaction chambers 1-8 are hollow cylindrical chambers made of 316L stainless steel. Their function is to contain the reaction samples, create the reaction environment, and ensure experimental safety and stability under high temperature and high pressure. Figure 5 As shown, the upper surface of the reaction chamber 1-8 has six threaded through holes evenly distributed for installing components such as the reaction chamber top cover 1-4. The interior of the reaction chamber 1-8 has three threaded holes evenly distributed at 90° intervals for installing the sample stage and heating assembly 2. The lower surface of the reaction chamber 1-8 has three additional threaded holes in addition to the six threaded through holes for installing the water cooling assembly 3. To dynamically control the pressure and temperature inside the reaction chamber, five through holes are provided on the side for welding two gas phase fluid inlet ports 1-9, two gas phase fluid outlet ports 1-10, and one electrical interface 1-11.

[0060] The gaseous fluid inlet ports 1-9 are made of 316L stainless steel. A standard Swagelok connector is welded to one end of the hollow metal tube, and the other end is welded to the reaction chamber 1-8. Their function is to facilitate the connection of the gaseous fluid from the gas cylinder, to introduce the gaseous fluid reactants into the gas-solid phase reaction, and to provide the high-pressure conditions for the reaction.

[0061] The gas phase fluid outlet 1-10 is made of 316L stainless steel. A standard Swagelok connector is welded to one end of the hollow metal tube, and the other end is welded to the reaction chamber 1-8. Its function is to facilitate the outlet of gas phase fluid or to refresh the gas phase fluid inside the reaction chamber, maintaining the high-pressure conditions required for the reaction.

[0062] The electrical interface 1-11 is made of 316L stainless steel, with a CF flange welded to one end of a hollow metal tube and the other end welded to the reaction tank cavity 1-8. Its function is to lead out the wiring of electrical components (such as electrodes and heaters) inside the cavity.

[0063] like Figure 6 As shown, the sample stage and heating assembly 2 consists of an electrode 2-1, a loading platform 2-2, a heater 2-3, a support platform 2-4, a conductive screw 2-5, a support fastening screw 2-6, a gasket 2-7, and a stud 2-8.

[0064] The sample is clamped and fixed to the platform 2-2 by electrode 2-1, and the platform 2-2 is fixed to the support 2-4 by conductive screw 2-5, while the heater 2-3 is clamped. The support fastening screw 2-6, along with the washer 2-7, is connected to the stud 2-8 under the support 2-4. The stud 2-8 is installed inside the reaction chamber 1-8.

[0065] The electrode 2-1 is made of tantalum, and there are 2 to 4 electrodes of it. It is configured as a slightly warped, elongated thin sheet. The warping allows the solid sample to have a certain thickness. A signal line is connected to the other end. Its function is to cooperate with the sample-carrying platform 2-2 to hold the sample; to apply a certain voltage to the sample; and to monitor the current signal passing through the sample.

[0066] The platform 2-2 is made of boron nitride and has a disk-like configuration. Its function is to place solid samples on it and ensure that they are heated uniformly.

[0067] The heater 2-3 is made of silicon nitride and is clamped between the platform 2-2 and the support 2-4. There are four electrical wires: two apply voltage for heating, and the other two are powered by thermocouples to monitor the heating temperature. According to the temperature tolerance of this invention, the internal thermocouples are type K. Their function is to provide the reaction temperature to the solid sample and simultaneously monitor the temperature.

[0068] The support platform 2-4 is made of 316L stainless steel. The grooves on its surface are for housing the heater 2-3. The four threaded holes on the upper surface are for fixing the electrode 2-1 and the platform 2-2. The three countersunk holes, spaced 90° apart, are for installing fasteners to secure the sample stage components, such as... Figure 7 As shown.

[0069] The conductive screws 2-5 are made of pure copper and there are 4 of them. Their function is to fix the electrode 2-1 and the loading platform 2-2 on the support platform 2-4.

[0070] The supporting fastening screws 2-6 are made of 316L stainless steel, and there are 3 of them. They are centered on the same circle and distributed at 90-degree intervals. Their function is to fix the support platform 2-4 on the stud 2-8.

[0071] The gaskets 2-7 are made of 316L stainless steel, and there are 6 of them. They protect the upper and lower surfaces of the support platform 2-4 and prevent stress concentration.

[0072] The studs 2-8 are made of 316L stainless steel and there are 3 of them. The support platform 2-4 is raised to a certain height to prevent direct contact with the reaction tank cavity 1-8, which would directly transfer heat and cause the lower surface temperature of the reaction tank cavity 1-8 to be high.

[0073] like Figure 8 As shown, the water-cooling component 3 includes an upper cover 3-1, a lower cover 3-2, a cooling pipe 3-3, a water-cooling fastening screw 3-4, and an overall connecting screw 3-5.

[0074] Cooling pipe 3-3 is placed inside lower cover 3-2. Water-cooled fastening screw 3-4 fixes upper cover 3-1 and lower cover 3-2 together to form a module. Overall connecting screw 3-5 connects water-cooled component 3 and reaction tank body 1.

[0075] The upper cover 3-1 is made of pure copper and is a flat disc. Its function is to seal the water-cooling component, so that the bottom of the reaction tank cavity 1-8 is cooled evenly and deformation caused by uneven temperature is avoided.

[0076] The lower cover 3-2 is made of 316L stainless steel and is a hollow cylinder with a hollowed-out interior to accommodate the cooling pipe 3-3. Figure 9 As shown, its function is to fix the cooling pipe and prevent it from burning the optical testing platform on which the device is installed.

[0077] The cooling pipe 3-3 is made of pure copper and is a hollow thin pipe with a certain shape. Its function is to allow cooling water to pass through and to cool the main body of the reaction tank 1 to the maximum extent.

[0078] The water-cooled fastening screws 3-4 are made of 316L stainless steel, and there are 3 of them. Their function is to fix the upper cover 3-1 and the lower cover 3-2 together to form a module.

[0079] The integral connecting screws 3-5 are made of 316L stainless steel, and there are 3 of them. Their function is to connect the water cooling component 3 and the main body of the reaction tank 1.

[0080] like Figure 10As shown, the electrical interface assembly 4 includes a tee tube 4-1, a thermocouple connector 4-2, and a feedthrough connector 4-3.

[0081] The three-way pipe 4-1 connects to the electrical interface 1-11, the thermocouple connector 4-2, and the feedthrough connector 4-3 respectively. The electrical wiring of the electrodes and heaters in the reaction chamber 1-8 is led out through the electrical interface 1-11 and connected to the thermocouple connector 4-2 and the feedthrough connector 4-3 respectively, and externally connected to the circuit or controller.

[0082] The tee pipe 4-1 is made of 316L stainless steel, and all three joints have knife-edge flanges, model DN16CF.

[0083] The thermocouple connector 4-2 has a housing made of 316L stainless steel, a knife-edge flange at the joint, and a model number of DN16CF. The internal sealing material is glass. Two pairs of positive and negative pins are located at the bottom. According to the standard for type K thermocouples, the materials for the positive and negative pins are specified as nickel-chromium and nickel-silicon alloy, respectively. One pair of pins can be used for monitoring inside the heater based on the thermoelectric effect, while the other pair is reserved for backup. If accurate temperature measurement of the sample is required, two wires can be directly fixed to the sample surface through electrode 2-1 and connected to the positive and negative pins.

[0084] The feedthrough connector 4-3 is made of 316L stainless steel, with a knife-edge flange at the joint, model DN16CF, and has 6 conductive pins at the bottom. In addition to the two thermocouple wires, the heater 2-3 is connected to two other wires for heating. The other four electrodes 2-1 are optional and require power supply.

[0085] Example

[0086] A. Design requirements and scope of application of this invention:

[0087] (1) Reaction temperature range: room temperature - 400℃

[0088] (2) Methods for controlling and monitoring intracavitary temperature:

[0089] The ceramic heater heats the sample platform, indirectly transferring heat to the solid sample. External control voltage input, controlling the temperature input of the heating element, is connected to the ceramic heater via a feedthrough connector. Additionally, the ceramic heater provides thermocouple terminals; connecting wires to the positive and negative pins of the thermocouple connector allows for external temperature measurement near the solid sample. For more accurate solid sample surface temperature measurement, two wires can be directly fixed to the sample surface via electrodes and connected to the positive and negative pins.

[0090] To prevent the characterization platform from being scalded by excessively high temperatures at the bottom of the reaction tank, a water-cooling system is installed at the bottom. A pump in the circulating water tank circulates deionized water in and out, cooling the tank. Note that deionized water should be replenished based on the liquid column outside the tank. The dynamic flow of gas also contributes to the cooling effect.

[0091] (3) Pressure range: 1-10 atm;

[0092] (4) Methods for controlling and monitoring intracavitary pressure:

[0093] The gas cylinder valve controls the flow of gaseous fluid through the switch, and the gas mass flow controller is adjusted to a closed-loop pressure control mode with flow monitoring to dynamically change the pressure of the gaseous fluid in the chamber. The gaseous fluid in the chamber is then discharged through the valve to the safety gas cabinet for processing.

[0094] (5) Sample: The sample shape is arbitrary, the size should be within the fixed range of the electrode, and the thickness can be adjusted according to the fixed height of the electrode.

[0095] B. The installation method of this invention is as follows:

[0096] like Figure 11 As shown, this invention can be directly installed on a Raman spectroscopy characterization platform through the bottom threaded hole of the device (including the water-cooling assembly). The gaseous fluid input inside the reaction chamber is achieved via a gas cylinder valve, which is then connected to the gaseous fluid inlet port of the reaction chamber body via a gas mass flow controller. The gaseous fluid output from the chamber is directly introduced into the safety gas cabinet via a gas valve. The cooling water in the water-cooling assembly is circulated and pumped in and out via a circulating water tank.

[0097] The wiring for the electrical components inside the cavity is provided by thermocouple connectors and feedthrough connectors. The thermocouple connectors have two pairs of alloy pins for positive and negative electrode insertion, used to measure temperature; the feedthrough connectors have six pins to provide voltage input to the four electrodes and the ceramic heater.

[0098] C. In-situ Raman spectroscopy testing method for metal-air batteries:

[0099] In an argon-filled glove box, place the solid sample on the sample stage, fix the solid sample on the platform with electrodes, and cover it with the top cover and seal all external connectors to prevent the battery from coming into contact with air; the solid sample can be a battery sample.

[0100] Remove the reaction cell from the glove box and fix it on the Raman spectroscopy characterization platform. Connect the gas phase fluid inlet / outlet connector to the external gas path. Connect the pins on the thermocouple connector and feedthrough connector to the external circuit to provide working voltage or collect signal current. The cooling pipe of the water-cooling component also needs to be connected to the circulating water tank.

[0101] Open the valve at the gas-phase fluid connector and introduce high-purity gas to replace the argon gas in the chamber. Continuously introduce the gas at a flow rate of 100 sccm. To simulate the working environment of the battery in situ, the electrolyte needs to reach a certain working temperature. Provide voltage to the ceramic heater until the temperature monitored by the thermocouple meets the requirements and maintain temperature stability. Power on the circulating water tank to cool the reaction chamber.

[0102] Meanwhile, the incident laser characterization platform monitors the composition changes caused by the chemical reaction during the operation of the reaction chamber; the external circuit monitors the electrochemical process of the battery based on the current changes on the electrodes.

[0103] Preferably, the material of the light-transmitting window in this invention is silicon dioxide with a thickness of 2 mm. Its transmittance in the visible light band can meet the requirements of in-situ Raman experiments. It can also be replaced with materials such as α-alumina, and the thickness can also be changed accordingly according to the transmittance. If it is necessary to test in-situ Raman experiments in other bands, a suitable light-transmitting window can be replaced.

[0104] Preferably, the reaction tank cavity, reaction tank top cover and joints and other parts in this invention need to be made of high-temperature resistant, corrosion resistant and high-strength materials. Since the reaction environment is harsh and the reaction gas may be corrosive, the material used in this invention is 316L stainless steel, which can also be replaced by titanium alloy, polyimide or ceramic.

[0105] Preferably, boron nitride is used as the thermal conductive material in this invention, but it can also be replaced with other thermal conductive materials such as silicon carbide, aluminum nitride, and graphene.

[0106] Preferably, in order to achieve a higher pressure within the reaction chamber, sealing rings are used at all locations in this invention. The materials used are polyimide or oxygen-free copper. At higher temperatures, the polyimide sealing ring at the top cover needs to be replaced with a gold sealing ring. Besides the above-mentioned sealing materials, other flexible materials such as aluminum, nickel, silicone rubber, and polytetrafluoroethylene can also be used as alternatives. The sealing rings are circular in shape and cross-section, but can also be replaced with square, rectangular, or elliptical shapes as needed, and their dimensions can be adjusted accordingly.

[0107] Preferably, the reaction chamber in this invention is cylindrical, but it can also be spherical, cubic, or polyhedral. The smaller the dead volume inside the chamber, the better, so as to facilitate the rapid turnover of the experimental gaseous fluid.

[0108] Preferably, the number of electrodes in this invention can be adjusted to 2 to 4 as needed. A two-electrode system can be used with only a positive electrode and a negative electrode, or a three-electrode system can be used, including a working electrode, a counter electrode and a reference electrode.

[0109] Preferably, the electrode in this invention is tantalum, but it can also be replaced with a conductive material with a high elastic modulus, such as stainless steel.

[0110] Preferably, in this invention, the light-transmitting window is cylindrical with a diameter of 13mm. The limit of the gas phase fluid pressure that the cavity can withstand is related to the mechanical strength of the light-transmitting window. If it is necessary to increase the gas phase fluid pressure in the cavity, a light-transmitting window of other shapes and sizes can be used instead.

[0111] Preferably, Raman experiments under high temperature conditions need to take into account the distance between the window and the sample. If the distance is too small, the lens or detector of the characterization instrument may be damaged due to high temperature. The distance between the window and the sample can be adjusted by using studs of different lengths to install the sample stage.

[0112] Preferably, all conductor materials involved in this invention are silver-plated copper, which can be replaced by copper wire, silver wire, aluminum wire or other conductive materials;

[0113] Preferably, the K-type thermocouple selected in this invention according to the required reaction temperature range can also be replaced with C, E, J, or R-type thermocouples, and the alloy material of the positive and negative pins on the corresponding thermocouple connector also needs to be changed.

[0114] Preferably, in this invention, the pins of the feedthrough connector need to supply power to the electrodes and heater, and need to be connected to a higher voltage. The material can be conductive materials such as gold, silver, or copper.

[0115] Preferably, the orientation of the water-cooling component does not need to be the same as that of the electrical interface component; it can be adjusted to be installed at a 90° or 180° angle.

[0116] Preferably, the present invention uses a CF knife-edge flange as the external sealing element, but other sealing methods such as KF flanges can also be used depending on the vacuum requirements;

[0117] Preferably, in this invention, the space between the reaction chamber and each interface is connected. In order to reduce the dead volume of gas in the sealed space, the diameter of the electrical interface on the reaction chamber can be adjusted.

[0118] Preferably, the gas phase fluid connector welded to the reaction tank cavity in this invention is a standard connector from Swagelok, which can be replaced by other connectors such as VCR connectors and hollow screws for the inlet and outlet of gas phase fluid.

[0119] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. 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 present invention.

Claims

1. A gas-phase reaction cell suitable for in-situ high-temperature electrochemical Raman experiments, characterized in that, Used for gas-solid phase chemical reactions, it features good airtightness, dynamic gas flow, controllable reaction environment, and modular structure for easy installation and disassembly. It includes the main body of the reaction cell, sample stage and heating components, water cooling components and electrical interface components. The sample stage and heating components are installed inside the reaction tank body. The water cooling components are fixed to the lower end face of the reaction tank body. The electrical interface components are connected through the electrical interface flange on the side wall of the reaction tank body. The main body of the reaction cell includes a window top cover, a light-transmitting window, a rectangular sealing ring, a reaction cell top cover, an O-ring sealing ring, window precision screws, cavity fastening screws, a reaction cell cavity, a gas phase fluid inlet interface, a gas phase fluid outlet interface, and an electrical interface; The top cover of the window, the light-transmitting window, and the top cover of the reaction tank are concentrically assembled. The top cover of the window is fixed to the top cover of the reaction tank by precision screws. A rectangular sealing ring is placed in a rectangular groove on the outside of the top cover of the reaction tank to prevent optical errors caused by deformation and damage due to uneven stress after the light-transmitting window is assembled. An O-ring is placed in a rectangular groove on the inside of the top cover of the reaction tank. The cavity fastening screws press the top cover of the reaction tank against the O-ring, fixing it to the cavity of the reaction tank and maintaining the internal pressure of the cavity. The gas phase fluid inlet, gas phase fluid outlet, and electrical interface are welded to the outer surface of the cavity of the reaction tank. The gas inside the cavity exchanges gas through the gas phase fluid inlet and outlet. The gas phase fluid inlet and outlet are symmetrically arranged relative to the electrical interface. The precision screws of the window and the cavity fastening screws are evenly distributed on the top cover of the window and the top cover of the reaction tank. The electrical circuits of the sensors and heaters inside the cavity are connected out through the electrical interface. The sample stage and heating assembly consist of electrodes, a loading platform, a heater, a support platform, conductive screws, support fastening screws, washers, and studs. The sample is clamped and fixed to the loading platform by the electrodes, and the conductive screws fix the loading platform to the support platform while clamping the heater. The groove on the surface of the support platform is used to place the heater. The support fastening screw, along with the washer, is connected to the stud under the support platform. The stud is installed inside the reaction tank cavity. The studs raise the support platform to a certain height to prevent it from directly contacting the reaction tank cavity; The water-cooling assembly includes an upper cover, a lower cover, cooling pipes, water-cooling fastening screws, and overall connecting screws. The cooling pipes are placed inside the lower cover, and the water-cooling fastening screws fix the upper cover and the lower cover to form a module. The overall connecting screws connect the water-cooling assembly to the main body of the reaction tank. The electrical interface assembly includes a tee tube, a thermocouple connector, and a feedthrough connector. The tee tube connects to the electrical interface, the thermocouple connector, and the feedthrough connector respectively. The electrical wiring of the electrodes and heaters inside the reaction chamber is led out through the electrical interface and connected to the thermocouple connector and the feedthrough connector respectively, and externally connected to the circuit or controller.

2. The gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The top cover of the window is a thick cover with a cylindrical hole in the center, and the material is 316L stainless steel. The light-transmitting window is a cylindrical flat lens made of silicon dioxide with a thickness of 2cm; The rectangular sealing ring has a rectangular cross-section and is made of polyimide. The material of the reaction tank top cover is 316L stainless steel. The upper surface has a stepped surface that needs to be polished for precision installation of the window top cover and rectangular grooves for rectangular sealing rings. The lower surface is flat and rectangular grooves are provided for O-ring seals. The O-ring has an O-shaped cross-section and is made of polyimide. The precision screws for the window are made of 316L stainless steel and there are 4 of them. The cavity fastening screws are made of 316L stainless steel and there are 6 of them, which fix the top cover of the reaction tank to the cavity of the reaction tank.

3. A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The reaction chamber is a hollow cylindrical cavity made of 316L stainless steel. Six threaded through holes are evenly distributed on the upper surface of the reaction chamber for installing the top cover. Three threaded holes, evenly distributed at 90° intervals, are located inside the reaction chamber for installing the sample stage and heating components. In addition to the six threaded through holes, the lower surface of the reaction chamber also has three threaded holes for installing water-cooling components. To dynamically control the pressure and temperature inside the reaction chamber, five through holes are provided on the side for welding two gas phase fluid inlet ports, two gas phase fluid outlet ports, and one electrical interface.

4. A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The material of the gas phase fluid inlet is 316L stainless steel. A standard connector is welded to one end of the metal hollow tube, and the other end is welded to the reaction tank cavity. The material of the gas phase fluid outlet is 316L stainless steel. A standard connector is welded to one end of the metal hollow tube, and the other end is welded to the reaction tank cavity. The electrical interface is made of 316L stainless steel, with a CF flange welded to one end of the metal hollow tube and the other end welded to the reaction tank cavity.

5. A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The electrodes are made of tantalum, numbered 2 to 4, and configured as micro-warp elongated thin sheets, which are used in conjunction with a sample-holding platform to hold the sample; a certain voltage is applied to the sample, and the current signal passing through the sample is monitored; The material of the loading platform is boron nitride, and its configuration is a disk. The heater is made of silicon nitride and is clamped by a loading platform and a support platform. The support platform is made of 316L stainless steel. The four threaded holes on the upper surface are for fixing the electrodes and the platform, and the three countersunk holes spaced 90° apart are for installing fasteners to fix the sample stage components. The conductive screws are made of pure copper and there are 4 of them, which are used to fix the electrode and the loading platform on the support. The supporting fastening screws are made of 316L stainless steel, and there are 3 of them. They are centered on the same circle and distributed at 90-degree intervals to fix the support platform on the studs. The gaskets are made of 316L stainless steel and there are 6 of them. They protect the upper and lower surfaces of the support platform and prevent stress concentration. The studs are made of 316L stainless steel and there are 3 of them.

6. A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The upper cover is made of pure copper and is a flat disc; The lower cover is made of 316L stainless steel and is a hollow cylinder with a hollowed-out interior to accommodate cooling pipes. The cooling pipe is made of pure copper and is a hollow thin pipe with a certain shape. The water-cooled fastening screws are made of 316L stainless steel and there are 3 of them. They are used to fix the upper cover and the lower cover to form a module. The integral connecting screws are made of 316L stainless steel and number 3, connecting the water-cooling component and the main body of the reaction tank.

7. A gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to claim 1, characterized in that, The tee pipe is made of 316L stainless steel, and all three joints have knife-edge flanges. The thermocouple connector has a housing material of 316L stainless steel, a knife-edge flange at the joint, glass as the internal sealing material, and two pairs of positive and negative pins at the bottom. The feedthrough connector is made of 316L stainless steel, with a knife-edge flange at the joint and six conductive pins at the bottom.

8. A method of using a gas-phase reaction cell for in-situ high-temperature electrochemical Raman experiments according to any one of claims 1-7, characterized in that, Methods for controlling and monitoring intracavitary temperature and pressure include: The ceramic heater heats the platform, indirectly transferring heat to the solid sample. External control voltage input, via a feedthrough connector, regulates the temperature input of the heating element. The ceramic heater provides thermocouple terminals; wires connect to the positive and negative pins of the thermocouple connector, allowing for external temperature measurement near the solid sample. For accurate solid sample surface temperature measurement, two wires are directly fixed to the sample surface via electrodes and connected to the positive and negative pins. To prevent overheating at the bottom of the reaction tank from scalding the characterization platform, a water-cooling system is installed at the bottom. A pump in the circulating water tank circulates deionized water, cooling the platform. The switch valve on the gas cylinder controls the opening and closing of the gas phase fluid inlet. The gas mass flow controller is set to a closed-loop pressure control mode with flow monitoring to dynamically change the pressure of the gas phase fluid in the chamber. The gas phase fluid in the chamber is then discharged through the valve to the safety gas cabinet for processing.

9. The method of use according to claim 8, characterized in that, In an argon-filled glove box, place the solid sample on the sample stage, fix the solid sample on the platform with electrodes, and cover it with the top cover and seal all external connectors to prevent the battery from coming into contact with air; the solid sample is the battery sample. Remove the reaction cell from the glove box and fix it on the Raman spectroscopy characterization platform. Connect the gas phase fluid inlet connector and the gas phase fluid outlet connector to the external gas path. Connect the pins on the thermocouple connector and the feedthrough connector to the external circuit to provide working voltage or collect signal current. Connect the cooling pipe of the water-cooling component to the circulating water tank. Open the valve at the gas phase fluid connector and introduce high-purity gas to replace the argon gas in the chamber. Continuously introduce the gas at a flow rate of 100 sccm. To simulate the working environment of the battery in situ, the electrolyte needs to reach a certain working temperature to provide voltage to the ceramic heater until the temperature monitored by the thermocouple meets the requirements and the temperature is maintained stable. Power on the circulating water tank to cool the reaction chamber. Meanwhile, the incident laser characterization platform monitors the composition changes caused by the chemical reaction during the operation of the reaction chamber; the external circuit monitors the electrochemical process of the battery based on the current changes on the electrodes.

10. The method of use according to claim 9, characterized in that, It includes a conventional mode and a high-temperature mode. In the conventional mode, the solid sample is fixed on the carrier platform, and the carrier platform is heated by a ceramic heater to transfer heat to the sample. During the reaction, the gas phase fluid is constantly flowing in and out. The proportion of gas phase fluid components in the chamber can be adjusted, or the pressure in the chamber can be controlled externally. Water cooling circulation occurs simultaneously with the gas inflow and outflow, and the temperature of the solid phase is relatively higher than that of the gas phase fluid. This mode is suitable for studying the changes of solid materials in gas-solid reactions or the changes of solid catalysts that assist gas phase fluid reactions. In high-temperature mode, to ensure airtightness within the chamber, the sealing rings at the top cover of the window and the top cover of the reaction tank are replaced with sealing rings made of pure gold before the experiment; the water cooling circulation is turned off to prevent heat loss; the solid sample is fixed on the carrier platform, and a certain proportion of gaseous fluid is introduced at the beginning of the reaction, and then the gaseous fluid inlet and outlet valves are closed. The carrier platform is heated by a ceramic heater to contact the solid phase for heat transfer. The temperature of the gaseous fluid increases continuously due to radiation and convection between the solid phase and the carrier platform, and the temperatures of the solid phase and the gaseous fluid become similar. This mode is suitable for studying surface reaction processes in gas-solid reactions or studying gaseous fluid reactions on the surface of solid catalysts.

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