Raman spectroscopy-confocal differential interference contrast microscopy combined analysis system

Abstract

The present invention relates to a Raman spectroscopy-confocal differential interference contrast microscope combined analysis system, characterized in that the system comprises: an electrochemical in-situ reaction device, which is used for in-situ testing of the electrode charging and discharging process and is provided with an optical window; a Raman spectroscopy system, which is used to realize the in-situ Raman spectroscopy test of the electrode electrochemical process by irradiating the optical window; and a confocal differential interference contrast microscope, which is used to obtain the optical imaging of the electrode in the electrochemical process by irradiating the optical window. The present invention can realize the in-situ Raman spectroscopy test and high-resolution optical imaging of the electrode process, ensure the synchronous detection of the material structure and chemical composition, and thus obtain more abundant interface electrochemical reaction information.

Description

Technical Field

[0001] The present invention relates to a Raman spectrum-confocal differential interference contrast microscope combined analysis system, which can synchronously analyze and detect the chemical components and material structure of an electrode process in real time and in situ, and relates to the technical field of electrochemical energy storage devices. Background Art

[0002] As energy issues become increasingly prominent, the research and development of electrochemical energy storage technology has become a hot topic, especially for lithium-ion batteries and secondary batteries such as sodium ions and potassium ions. Currently, a large number of studies are focused on improving the cycle life and electrochemical performance of such batteries, as well as optimizing storage devices. The electrode / electrolyte interface is an important component of secondary batteries. Systematic exploration of the reaction mechanism, kinetic behavior and attenuation mechanism of the electrochemical charge and discharge process of the battery interface is a prerequisite for further improving battery performance. However, there are only a handful of studies on this work at home and abroad, and most of the research methods are in the non-in-situ characterization stage, and cannot perform real-time detection of the microstructure or material components of the interfacial electrochemical process. How to conduct in-situ research on the electrode / electrolyte interface of the battery to obtain more accurate and reliable test data is an urgent problem to be solved.

[0003] In recent years, confocal differential interference contrast microscopy (LCM-DIM) has become a new optical microscopic imaging technology due to its advantages of high spatial resolution up to nanometers in the Z axis, high temporal resolution (scanning speed 0.25 seconds / frame) and spatial non-interference. Therefore, LCM-DIM can observe the electrode / electrolyte solid-liquid interface dynamics process in situ at the nanoscale quickly and in real time.

[0004] However, high-resolution optical imaging technology can only measure the surface morphology of samples, and cannot perform functional identification of material components like in-situ spectroscopy technology. At the same time, single spectroscopy technology can only detect the material elements or molecular structure of the sample in situ, but cannot monitor the microstructure of the sample in real time. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide a Raman spectroscopy-confocal differential interference contrast microscope combined analysis system that can efficiently characterize the characteristics of the battery interface.

[0006] To achieve the above object, the present invention adopts the following technical solution: a Raman spectroscopy-confocal differential interference contrast microscope combined analysis system, the system comprising:

[0007] An electrochemical in-situ reaction device, used for in-situ testing of the electrode charge and discharge process and provided with an optical window;

[0008] Raman spectroscopy system, used to realize in-situ Raman spectroscopy testing of the electrode electrochemical process by irradiating the optical window, and obtain the molecular structure and chemical composition of the working electrode at different voltages;

[0009] A confocal differential interference contrast microscope system is used to obtain optical imaging of the electrode during an electrochemical process by illuminating the optical window.

[0010] In some embodiments of the present invention, the electrochemical in-situ reaction device includes a first packaging shell, a second packaging shell and a planar battery; the first packaging shell and the second packaging shell are fixedly connected by bolts; the planar battery is fixedly arranged between the first shell and the second packaging shell, the working electrode of the planar battery is connected to the second packaging shell, and the counter electrode of the planar battery is connected to the first packaging shell.

[0011] In some embodiments of the present invention, the first packaging shell includes a first insulating plate, a first conductive plate, a second insulating plate and a first sealing ring; the second packaging shell includes a second conductive plate, a third insulating plate, a quartz plate, a second sealing ring and a third sealing ring; the planar battery includes a working electrode, a solid electrolyte membrane, a counter electrode and a pressurized fixing member;

[0012] The first insulating plate and the first conductive plate are fixedly connected, and a battery slot is provided at the bottom of the first conductive plate; the pressurized fixing member, the counter electrode, the solid electrolyte membrane and the working electrode are arranged in sequence from top to bottom in the battery slot; a second insulating plate and a first sealing ring are provided at the bottom of the first conductive plate located outside the battery slot;

[0013] The second conductive plate is disposed at the bottom of the second insulating plate, corresponding to the battery slot, and the second conductive plate is provided with a first optical window; the third insulating plate is disposed at the bottom of the second conductive plate, corresponding to the first optical window, and the third insulating plate is provided with a second window;

[0014] The quartz plate is arranged between the first optical window and the second optical window via a second sealing ring and a third sealing ring.

[0015] In some embodiments of the present invention, the Raman spectroscopy system includes a laser light source, a first color filter, a dichroic mirror, a microscope objective, a first semi-transparent and semi-reflective mirror, a first lens, a second color filter, a first reflector, a second lens, a Raman spectrometer and a CCD detector; the laser signal generated by the laser light source is transmitted to the dichroic mirror through the first color filter, the dichroic mirror splits the laser signal, the laser signal reflected by the dichroic mirror is transmitted to the microscope objective, the microscope objective faces the second optical window, the microscope objective focuses the laser signal on the working electrode, the Raman signal generated by the working electrode is collected by the microscope objective, then reflected by the dichroic mirror and the first semi-transparent and semi-reflective mirror, and sequentially passes through the first lens, the second color filter, the first reflector and the second lens, and is coupled into the Raman spectrometer for Raman signal detection; the CCD detector is used to assist in observing the surface of the working electrode.

[0016] In some embodiments of the present invention, the confocal differential interference contrast microscope system includes an illumination light source, a second reflector, a polarizer, a second semi-transparent and semi-reflective mirror, an optical assembly, a third reflector, a Nomarski prism, a confocal aperture pinhole, an analyzer, and a photomultiplier tube;

[0017] The light emitted by the illumination light source is reflected by the second reflector and enters the polarizer to generate linear polarized light. The linear polarized light is reflected by the second semi-transparent and semi-reflective mirror and enters the optical assembly to adjust the direction of the light path, and is reflected by the third reflector to the Nomarski prism to decompose the linear polarized light into two beams of light with polarization directions perpendicular to each other. The two beams of light are sequentially transmitted through the first semi-transparent and semi-reflective mirror, the dichroic mirror and the microscope objective lens to irradiate the working electrode. The two light beams reflected by the working electrode are sequentially transmitted through the microscope objective lens, the dichroic mirror and the first semi-transparent and semi-reflective mirror to the Nomarski prism. The Nomarski prism makes the two beams of light recombine and become collinear again, and then sequentially pass through the third reflector, the optical assembly, the second semi-transparent and semi-reflective mirror, the confocal aperture pinhole and the analyzer to be received by the photomultiplier tube, and the optical imaging of the working electrode is obtained after processing.

[0018] In some embodiments of the present invention, the wavelength of the laser light source is 532 nm.

[0019] In some embodiments of the present invention, the illumination light source is a superluminescent diode.

[0020] The present invention adopts the above technical solution, which has the following advantages:

[0021] 1. The Raman spectroscopy-confocal differential interference contrast microscope combined analysis system of the present invention perfectly combines the Raman spectrometer system and the confocal differential interference contrast microscope system, and has the functions of Raman spectrometer and high-resolution optical imaging at the same time, and can obtain the relevant material components at the same position while analyzing the surface morphology structure of the sample to be tested;

[0022] 2. The present invention is aimed at the electrochemical system in the energy storage device, which makes up for the lack of in-situ characterization means of electrode process and in-situ electrochemical reaction device;

[0023] In summary, the present invention can achieve high spatial resolution and high temporal resolution in situ tracking of electrode processes, and can realize simultaneous monitoring of interface structure and corresponding species analysis, thereby obtaining richer electrochemical interface reaction information. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are only used for the purpose of illustrating preferred embodiments and are not to be considered as limiting the present invention. The same reference numerals are used to represent the same components throughout the accompanying drawings. In the accompanying drawings:

[0025] Figure 1 This is a light path structure diagram of the Raman spectroscopy-confocal differential interference contrast microscope combined analysis system of this embodiment;

[0026] Figure 2 Schematic diagram of the structure of the electrochemical in-situ reaction device of this embodiment. DETAILED DESCRIPTION

[0027] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0028] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0029] like Figure 1 As shown, the Raman spectroscopy-confocal differential interference contrast microscopy combined analysis system provided in this embodiment includes an electrochemical in-situ reaction device 1, a Raman spectroscopy system and a confocal differential interference contrast microscopy system, wherein the electrochemical in-situ reaction device 1 is placed on a test bench 2.

[0030] An electrochemical in-situ reaction device 1, used for in-situ testing of the electrode charge and discharge process and provided with an optical window;

[0031] Raman spectroscopy system, used to realize in-situ Raman spectroscopy testing of the electrode electrochemical process by irradiating the optical window, and obtain the molecular structure and chemical composition of the working electrode at different voltages;

[0032] The confocal differential interference contrast microscope system is used to obtain optical imaging of the electrode electrochemical process by illuminating the optical window and obtain the microstructure of the working electrode at different voltages.

[0033] Specifically, the Raman spectroscopy system includes a laser light source 3 , a color filter 4 , a dichroic mirror 5 , a microscope objective 6 , a semi-transparent and semi-reflective mirror 7 , a lens 8 , a color filter 9 , a reflector 10 , a lens 11 , a Raman spectrometer 12 and a CCD detector 13 .

[0034] The laser signal generated by the laser light source 3 is emitted to the dichroic mirror 5 through the color filter 4. The dichroic mirror 5 splits the laser signal. The laser signal reflected by the dichroic mirror 5 is emitted to the microscope objective 6. The microscope objective 6 faces the optical window of the electrochemical in-situ reaction device 1 to be tested on the test bench 2. The microscope objective 6 focuses the laser signal on the working electrode of the electrochemical in-situ reaction device 1 to be tested. At the same time, the CCD detector 13 is used to assist in observing the surface of the working electrode. The molecules of the substance on the electrode surface scatter the incident light. The scattered Raman spectrum signal is collected by the microscope objective 6 and then passes through the dichroic mirror 5. The Raman signal transmitted by the dichroic mirror 5 is reflected by the semi-transparent and semi-reflective mirror 7, and sequentially passes through the lens 8, the color filter 9, the reflector 10 and the lens 11, and is coupled into the Raman spectrometer 12 for Raman signal detection, which can quickly characterize the molecular structure and chemical composition of the electrode to be tested under different voltages. Among them, the function of the dichroic mirror 5 is to reflect the laser signal and transmit the Raman signal; the function of the semi-transparent and semi-reflective mirror 7 is to reflect the generated Raman signal; in addition, the microscope objective lens 6, the dichroic mirror 5 and the semi-transparent and semi-reflective mirror 7 are arranged in sequence from top to bottom under the test bench 2, and the center lines of the microscope objective lens 6, the dichroic mirror 5 and the semi-transparent and semi-reflective mirror 7 are on the same vertical straight line to ensure that the Raman signal can pass smoothly.

[0035] Specifically, the confocal differential interference contrast microscope system includes a superluminescent diode 14, a reflector 15, a polarizer 16, a semi-transparent and semi-reflective mirror 17, an optical assembly 18, a reflector 19, a Nomarski prism 20, a confocal aperture 21, an analyzer 22 and a photomultiplier tube 23.

[0036] The light emitted by the superluminescent diode 14 is reflected by the reflector 15 and enters the polarizer 16. The polarizer 16 is used to make the light emitted by the superluminescent diode 14 produce linear polarization. The linear polarized light is reflected by the semi-transparent and semi-reflective mirror 17 and enters the optical assembly 18 to adjust the direction of the light path. Then, it is reflected by the reflector 19 and passes through the Nomarski prism 20 to decompose the linear polarized light into two beams of light with polarization directions perpendicular to each other. The two beams of light pass through the semi-transparent and semi-reflective mirror 7, the dichroic mirror 5 and the microscope objective lens 6 in turn with a very small lateral offset, and are incident on the surface of the working electrode of the electrochemical in-situ reaction device 1 to be measured. Due to the different heights of the incident points, an optical path difference is formed. The two light beams reflected by the working electrode pass through the microscope objective lens 6, the dichroic mirror 5, the semi-transparent and semi-reflective mirror 7 and the Nomarski prism 20 in turn. The Nomarski prism 20 makes the two beams of light recombine and collinear again, and another part of the optical path difference is generated in the process of the light passing through the Nomarski prism, and then in turn The light is received by the photomultiplier tube 23 through the reflector 19, the optical assembly 18, the semi-transparent and semi-reflective mirror 17, the confocal aperture pinhole 21 and the analyzer 22, wherein the analyzer 22 is used to combine the two light waves into two light beams with the same polarization direction, so that the two light waves interfere with each other. At this time, the phase difference formed by the total optical path difference between the two light waves on the sample surface and through the Nomarski prism will form a light-dark contrast in the interference fringes. According to this contrast, the difference in the surface structure and the convex-concave direction of the sample will be reflected, and finally a surface 3D imaging will be formed. The interference signal received by the photomultiplier tube 23 is converted into an electrical signal for processing to obtain the structural conversion imaging of the electrode surface under the electrochemical environment. Among them, the dichroic mirror 5 in the confocal differential interference contrast microscope system can allow the light beam signal to pass directly; the semi-transparent and semi-reflective mirror 7 in the confocal differential interference contrast microscope system can directly pass the light beam signal. In the confocal differential interference contrast microscope system, the center lines of the microscope objective 6, the dichroic mirror 5, the semi-transparent and semi-reflective mirror 7 and the Nomarski prism 20 are on the same vertical straight line to ensure a smooth optical path, wherein the optical assembly 18 can use a reflector to adjust the direction of the optical path.

[0037] In summary, the Raman spectroscopy system and the confocal differential interference contrast microscope system of the present embodiment share a dichroic mirror 5 and a semi-transparent and semi-reflective mirror 7, thereby realizing the combined use of the Raman spectroscopy system and the confocal differential interference contrast microscope system, and sharing a test bench 2 and a microscope objective lens 6, so that the Raman spectrum and high-resolution optical imaging data can be collected at the same position of the electrochemical in-situ reaction device, and the relevant material composition can be obtained at the same position while analyzing the surface morphology structure of the sample to be tested.

[0038] Specifically, Figure 2 As shown, the electrochemical in-situ reaction device 1 includes a first packaging shell, a second packaging shell and a planar battery.

[0039] The first packaging shell and the second packaging shell are fixedly connected by bolts, and the flat battery is fixed and sealed by the extrusion force between the first packaging shell and the second packaging shell. The working electrode of the flat battery is connected to the second packaging shell, and the counter electrode of the flat battery is connected to the first packaging shell.

[0040] Preferably, the first packaging shell includes a first insulating plate 1-1, a first conductive plate 1-2, a second insulating plate 1-3 and a first sealing ring 1-4, and a battery slot is provided at the bottom of the first conductive plate 1-2;

[0041] The second packaging shell includes a second conductive plate 1-5, a third insulating plate 1-6, a quartz plate 1-7, a second sealing ring 1-8 and a third sealing ring 1-9;

[0042] The flat battery includes a working electrode 1-10, a diaphragm (or solid electrolyte membrane) 1-11, a counter electrode 1-12, a pressurized fixture 1-13 and a battery container 1-14, wherein the specific installation process of the electrochemical in-situ reaction device is as follows:

[0043] First, assemble the first packaging shell, that is, fix the first insulating plate 1-1 and the first conductive plate 1-2 by screws, and then place the second insulating plate 1-3 and the first sealing ring 1-4 on the first conductive plate 1-2 outside the battery slot;

[0044] Next, the second packaging shell is assembled, that is, the second conductive plate 1-5, the second sealing ring 1-9, the quartz plate 1-7, the third sealing ring 1-8 and the third insulating plate 1-6 are assembled in sequence and then fixed by screws, wherein the second conductive plate 1-5 and the third insulating plate 1-6 are both provided with optical windows;

[0045] Next, the pressurized fixture 1-13, the counter electrode 1-12, the diaphragm (or solid electrolyte membrane) 1-11 and the working electrode 1-10 are sequentially placed in the battery slot 1-14 of the first conductive plate 1-2, and then the assembled second packaging shell is placed on the first packaging shell; finally, the screws 1-15 that pass through the fixing holes of the third insulating plate 1-6, the second conductive plate 1-5, the second insulating plate 1-3, the first conductive plate 1-2 and the first insulating plate 1-1 are fixed by nuts 1-16 to assemble as shown in the figure. Figure 2 The device shown in the figure, wherein the pressurized fixing part 1-13 contacts the bottom of the first conductive plate, the working electrode contacts the top of the second conductive plate 1-5, wires are connected from the first conductive plate 1-2 and the second conductive plate 1-5 respectively, and are connected to an electrochemical analyzer for electrochemical testing. At the same time, the device is placed on a test bench 2, and through the optical window at the second conductive plate 1-5, in-situ Raman spectroscopy testing and high-resolution optical observation of the electrode electrochemical process can be achieved.

[0046] In some embodiments of the present invention, the first conductive plate 1-2 and the second conductive plate 1-5 are both made of stainless steel, and corresponding screw holes are provided; the first insulating plate 1-1, the second insulating plate 1-3 and the third insulating plate 1-6 are all made of polytetrafluoroethylene, and corresponding screw holes are provided.

[0047] In some embodiments of the present invention, the Raman spectroscopy system uses a 532 nm laser light source 3, and the confocal differential interference contrast microscope system uses a superluminescent diode 14 as an illumination light source.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A Raman spectroscopy-confocal differential interference contrast microscope combined analysis system, characterized in that: The system includes: An electrochemical in-situ reaction device, used for in-situ testing of the electrode charge and discharge process and provided with an optical window; A Raman spectroscopy system is used to implement in-situ Raman spectroscopy testing of an electrode electrochemical process by irradiating an optical window, and obtain the molecular structure and chemical composition of a working electrode under different voltages; the Raman spectroscopy system comprises a laser light source, a first color filter, a dichroic mirror, a microscope objective, a first semi-transparent and semi-reflective mirror, a first lens, a second color filter, a first reflective mirror, a second lens, a Raman spectrometer and a CCD detector; a laser signal generated by the laser light source is emitted to the dichroic mirror via the first color filter, the dichroic mirror splits the laser signal, and the laser signal reflected by the dichroic mirror is emitted to the microscope objective, the microscope objective faces the optical window, and the microscope objective focuses the laser signal on the working electrode of the electrochemical in-situ reaction device, and the Raman signal generated by the working electrode is collected by the microscope objective, then reflected by the dichroic mirror via the first semi-transparent and semi-reflective mirror, and sequentially passes through the first lens, the second color filter, the first reflective mirror and the second lens, and is coupled into the Raman spectrometer for Raman signal detection; the CCD detector is used to assist in observing the surface of the working electrode; A confocal differential interference contrast microscope system is used to obtain optical imaging of the electrode in an electrochemical process by irradiating the optical window; the confocal differential interference contrast microscope system comprises an irradiation light source, a second reflector, a polarizer, a second semi-transparent and semi-reflective mirror, an optical assembly, a third reflector, a Nomarski prism, a confocal aperture pinhole, an analyzer and a photomultiplier tube; the light emitted by the irradiation light source is reflected by the second reflector into the polarizer to generate linear polarized light, the linear polarized light is reflected by the second semi-transparent and semi-reflective mirror into the optical assembly to adjust the light path direction, and is reflected by the third reflector The light is reflected by the reflector to the Nomarski prism to decompose the linear polarized light into two beams of light with mutually perpendicular polarization directions; the two beams of light are sequentially transmitted through the first semi-transparent and semi-reflective mirror, the dichroic mirror and the microscope objective to irradiate the working electrode, and the two beams of light reflected by the working electrode are sequentially transmitted through the microscope objective, the dichroic mirror and the first semi-transparent and semi-reflective mirror to the Nomarski prism, and the Nomarski prism makes the two beams of light recombine and become collinear, and then sequentially pass through the third reflector, the optical assembly, the second semi-transparent and semi-reflective mirror, the confocal aperture pinhole and the analyzer to be received by the photomultiplier tube, and the optical imaging of the working electrode is obtained after processing.

2. The Raman spectroscopy-confocal differential interference contrast microscope combined analysis system according to claim 1, characterized in that: The electrochemical in-situ reaction device comprises a first packaging shell, a second packaging shell and a planar battery; the first packaging shell and the second packaging shell are fixedly connected by bolts; the planar battery is fixedly arranged between the first packaging shell and the second packaging shell, the working electrode of the planar battery is connected to the second packaging shell, and the counter electrode of the planar battery is connected to the first packaging shell.

3. The Raman spectroscopy-confocal differential interference contrast microscope combined analysis system according to claim 2, characterized in that: The first packaging shell includes a first insulating plate, a first conductive plate, a second insulating plate and a first sealing ring; the second packaging shell includes a second conductive plate, a third insulating plate, a quartz plate, a second sealing ring and a third sealing ring; the planar battery includes a working electrode, a solid electrolyte membrane, a counter electrode and a pressurized fixing member; The first insulating plate and the first conductive plate are fixedly connected, and a battery slot is provided at the bottom of the first conductive plate; the pressurized fixing member, the counter electrode, the solid electrolyte membrane and the working electrode are arranged in sequence from top to bottom in the battery slot; a second insulating plate and a first sealing ring are provided at the bottom of the first conductive plate located outside the battery slot; The second conductive plate is disposed at the bottom of the second insulating plate, corresponding to the battery slot, and the second conductive plate is provided with a first optical window; the third insulating plate is disposed at the bottom of the second conductive plate, corresponding to the first optical window, and the third insulating plate is provided with a second window; The quartz plate is arranged between the first optical window and the second optical window via a second sealing ring and a third sealing ring.

4. The Raman spectroscopy-confocal differential interference contrast microscope combined analysis system according to claim 1, characterized in that: The wavelength of the laser light source is 532 nm.

5. The Raman spectroscopy-confocal differential interference contrast microscope combined analysis system according to claim 1, characterized in that: The irradiation light source is a super luminescent diode.

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