Method for removing ice pollution of electrochemical sample of cryoelectron microscope and application

Abstract

The invention discloses a method for removing ice pollution of an electrochemical sample of a cryoelectron microscope and application, and belongs to the technical field of preparation of cryoelectron microscope samples. The method comprises the following steps: firstly, filling a transfer cabin and a Dewar tank for freezing and transmitting a sample rod with liquid nitrogen; the temperature of the front end of the sample freezing and conveying rod is controlled to be-120 DEG C or below, and the temperature of the Dewar tank is controlled to be-180 DEG C or below; installing the copper mesh attached with the solid electrolyte electrochemical sample in a liquid nitrogen environment into a freezing transmission sample rod, and then placing the freezing transmission sample rod into a transmission electron microscope; and finally, emptying the liquid nitrogen in the Dewar tank, immediately stopping heating when the temperature of the front end of the freezing transmission sample rod is raised to-90 DEG C, and then adding the liquid nitrogen into the Dewar tank for cooling, so that ice pollution can be removed. By regulating and controlling the temperature and the liquid nitrogen environment of the front end of the freezing transmission sample rod and the Dewar tank, ice pollution in the electrochemical sample attached with the solid electrolyte can be removed, and the authenticity of the electrochemical sample can be conveniently observed by adopting a freezing electron microscope.

Description

Technical Field

[0001] The present invention belongs to the technical field of cryo-electron microscopy sample preparation, and in particular relates to a method and application for removing ice contamination from cryo-electron microscopy electrochemical samples. Background Art

[0002] As people are eager to observe electrochemical reactions in electrode materials, they are more aware of the importance of deeply understanding the relationship between the evolution of material microstructure and performance. All-solid-state lithium batteries based on solid electrolytes are one of the ultimate solutions to the current safety problems of lithium-ion batteries. However, the interface problems of solid-state batteries lead to poor performance of solid-state batteries, which greatly limits the development of all-solid-state batteries in the field of new energy. The study of interfaces plays a vital role in all-solid-state batteries. At present, the research on interfaces is mostly based on X-ray diffraction, X-ray photoelectron spectroscopy and other methods, while microscopic characterization methods, especially transmission electron microscopy, are still difficult to use in research. Transmission electron microscopy technology plays an irreplaceable role in studying the evolution and growth mechanism of interfaces. Electrode materials and electrolytes are sensitive to the electron beam of the transmission electron microscope, and it is easy to fail to obtain real information when obtaining information about samples.

[0003] Cryo-electron microscopy technology is currently widely used in the field of biopolymers. It makes it possible to observe samples that are sensitive to electron beams and can reduce the damage caused by electron beams to samples. However, solid-state battery samples can only be transferred by freezing in liquid nitrogen. It is difficult to avoid the formation of ice crystals during the sample preparation process, thereby contaminating the samples. Moreover, the electrolytes in solid-state batteries, especially sulfide electrolytes and halide electrolytes, are extremely sensitive to water and will decompose when exposed to water. When collecting high-magnification transmission photographs, ice crystals are easily melted by electron beam irradiation, thereby reacting with the sample and obtaining no true information about the sample. Therefore, ice contamination is still a very challenging problem in cryo-electron microscopy, especially for water-sensitive samples. Summary of the invention

[0004] In response to the above technical problems, the present invention proposes a method for removing ice contamination from cryo-electron microscopy electrochemical samples.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A method for removing ice contamination from a cryo-electron microscopy electrochemical sample comprises the following steps:

[0008] (1) Filling the transfer chamber and the dewar tank of the cryotransfer sample rod with liquid nitrogen; and controlling the temperature of the front end of the cryotransfer sample rod to be below -120° C. and the temperature of the dewar tank to be below -180° C.;

[0009] (2) installing a copper mesh with a solid electrolyte electrochemical sample in a liquid nitrogen environment into a cryotransfer sample holder, and then placing the cryotransfer sample holder in a transmission electron microscope;

[0010] (3) Empty the liquid nitrogen in the Dewar tank, and stop heating the front end of the cryotransfer sample rod when the temperature rises to -90°C. Then add liquid nitrogen to the Dewar tank to cool it down, and ice contamination can be removed.

[0011] Preferably, the model of the cryotransfer sample rod is Fischione Model 2550.

[0012] Preferably, the electrochemical sample with solid electrolyte includes a microgrid with solid electrolyte particles or a solid battery slice processed by focused ion beam.

[0013] Preferably, the electron microscope model used in the focused ion beam processing is Helios G4 cx

[0014] Preferably, the solid electrolyte includes but is not limited to a sulfide electrolyte or a halide electrolyte.

[0015] Preferably, the solid electrolyte includes but is not limited to NZC electrolyte or NPS electrolyte.

[0016] Preferably, the front end of the cryotransfer sample rod and the Dewar tank are connected with a controller for controlling the temperature.

[0017] Preferably, the electrochemical samples after step (2) and step (3) are photographed using a transmission electron microscope.

[0018] Preferably, the model of the transmission electron microscope is FEI-Titan G2.

[0019] The second technical solution of the present invention:

[0020] The above method for removing ice contamination from cryo-electron microscopy electrochemical samples is applied in microscopic observation of solid-state batteries. Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] (1) The electrode material and the electrolyte are relatively sensitive to the electron beam, and it is easy to fail to obtain true information when obtaining information about the sample; the present invention uses a cryo-electron microscope to observe the sample and characterize the fine structure of the electrode material and the electrolyte at liquid nitrogen temperature, which can effectively reduce the damage of the electron beam to the sample;

[0022] (2) It is difficult to avoid the generation of ice crystals in the sample preparation process of solid-state battery electrochemical samples, and the samples are extremely sensitive to water and will react with water to damage the samples. The method of the present invention removes ice contamination and retains the original sample, so that the real information of the sample can be collected. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 This is an electron microscope image of the NZC sample of Example 1 of the present invention transferred to an electron microscope;

[0025] Figure 2 This is an electron microscope image of the NZC sample after ice contamination is removed from Example 1 of the present invention;

[0026] Figure 3 This is an electron microscope image of the NPS sample transferred to an electron microscope in Example 2 of the present invention;

[0027] Figure 4 This is an electron microscope image of the NPS sample after ice contamination is removed from Example 2 of the present invention. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] The present invention provides a method for removing ice contamination from cryo-electron microscopy electrochemical samples, making it applicable to various electrochemical systems. In the preferred embodiment of the present invention, typical but non-limiting examples include NZC electrolyte and NPS electrolyte. Among them, the NZC electrolyte used in the following embodiments is Na2ZrCl6, and the preparation process is: NaCl (99.99%, Alfa Aeser) and ZrCl4 (99.99%, Sigma Aldrich) mixed in stoichiometric amounts are placed in a ZrO2 vial containing ZrO2 balls, and ball milled at a speed of 600 rpm for 10 hours using a Pulverisette 7PL (Fritsch GmbH). For further heat treatment, the ball-milled powder was placed in a vacuum-sealed fused quartz ampoule and annealed at 400°C for 12 hours; the NPS electrolyte was Na3PS4, which was prepared by ball-milling a stoichiometric mixture of Na2S (SigmaAldrich) and P2S5 (99%, SigmaAldrich), and then heat-treating it at 270°C for 1 hour in a vacuum-sealed fused quartz ampoule.

[0034] A method for removing ice contamination from cryo-electron microscopy electrochemical samples, comprising the following specific steps:

[0035] (1) placing a microgrid with solid electrolyte particles or a copper mesh with a solid-state battery sheet processed by a focused ion beam prepared in a glove box filled with argon atmosphere into a thermos cup filled with liquid nitrogen;

[0036] (2) Fill the transfer chamber and dewar tank of the cryotransfer sample rod with liquid nitrogen, connect the controller to ensure that the temperature of the front end of the sample rod drops to -120°C or below, and the temperature of the dewar tank drops to -180°C or below;

[0037] (3) Mount the sample into a cryotransfer sample holder in liquid nitrogen and place it into a transmission electron microscope;

[0038] (4) Take a photo to check ice contamination;

[0039] (5) Empty the liquid nitrogen in the Dewar tank, connect the controller, heat the sample rod, and stop heating immediately when the temperature at the front end of the sample rod reaches -90°C, and add liquid nitrogen to the Dewar tank to cool it down;

[0040] (6) Take a photo to check the ice pollution removal status.

[0041] The raw materials used in the present invention are all purchased from the market.

[0042] The technical solution of the present invention is further illustrated by the following embodiments.

[0043] Example 1

[0044] (1) Place the copper mesh with NZC electrolyte processed by FEI-Helios G4 cx focused ion beam into a thermos cup filled with liquid nitrogen;

[0045] (2) Fill the transfer chamber and dewar tank of the Fischione Model 2550 cryotransfer sample holder with liquid nitrogen and connect the controller to ensure that the temperature of the front end of the sample holder drops to -120°C and the temperature of the dewar tank drops to -189°C;

[0046] (3) Mount the sample into a cryotransfer sample holder in liquid nitrogen and place it into a FEI-Titan G2 transmission electron microscope;

[0047] (4) Take a photo and check the ice contamination. Figure 1 As shown, there are sporadically dispersed areas of ice contamination on the samples;

[0048] (5) Empty the liquid nitrogen in the Dewar tank, connect the controller, heat the sample rod, and stop heating immediately when the temperature at the front end of the sample rod reaches -90°C, and add liquid nitrogen to the Dewar tank to cool it down;

[0049] (6) Take a photo to check the ice pollution removal status, such as Figure 2 As shown, all ice on the sample was removed.

[0050] Example 2

[0051] (1) Place the copper mesh with NPS electrolyte processed by FEI-Helios G4 cx focused ion beam into a thermos cup filled with liquid nitrogen;

[0052] (2) Fill the transfer chamber and dewar tank of the Fischione Model 2550 cryotransfer sample holder with liquid nitrogen and connect the controller to ensure that the temperature of the front end of the sample holder drops to -120°C and the temperature of the dewar tank drops to -189°C;

[0053] (3) Mount the sample into a cryotransfer sample holder in liquid nitrogen and place it into a FEI-Titan G2 transmission electron microscope;

[0054] (4) Take a photo and check the ice contamination. Figure 3 As shown, there are sporadically dispersed areas of ice contamination on the samples;

[0055] (5) Empty the liquid nitrogen in the Dewar tank, connect the controller, heat the sample rod, and stop heating immediately when the temperature at the front end of the sample rod reaches -90°C, and add liquid nitrogen to the Dewar tank to cool it down;

[0056] (6) Take a photo to check the ice pollution removal status, such as Figure 4 As shown, all ice on the sample was removed.

[0057] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for removing ice contamination from cryo-electron microscopy electrochemical samples, characterized in that: The following steps are involved: (1) Filling the transfer chamber and the dewar tank of the cryotransfer sample rod with liquid nitrogen; and controlling the temperature of the front end of the cryotransfer sample rod to be below -120° C. and the temperature of the dewar tank to be below -180° C.; (2) installing a copper mesh with a solid electrolyte electrochemical sample in a liquid nitrogen environment into a cryotransfer sample holder, and then placing the cryotransfer sample holder in a transmission electron microscope; (3) Empty the liquid nitrogen in the Dewar tank, and stop heating the front end of the cryotransfer sample rod when the temperature rises to -90°C. Then add liquid nitrogen to the Dewar tank to cool it down, and ice contamination can be removed.

2. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 1, characterized in that: The model of the cryotransfer sample holder is Fischione Model 2550.

3. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 1, characterized in that: The electrochemical sample with solid electrolyte includes a microgrid with solid electrolyte particles or a solid battery slice processed by focused ion beam.

4. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 3, characterized in that: The electron microscope model used in the focused ion beam processing is Helios G4 cx.

5. A method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 1 or 3, characterized in that: The solid electrolyte includes a sulfide electrolyte or a halide electrolyte.

6. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 5, characterized in that: The solid electrolyte includes an NZC electrolyte or an NPS electrolyte.

7. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 1, characterized in that: The front end of the cryotransfer sample rod and the Dewar tank are respectively connected with controllers for controlling the temperature.

8. The method for removing ice contamination from cryo-electron microscopy electrochemical samples according to claim 1, characterized in that: The model of the transmission electron microscope is FEI-Titan G2.

9. Application of the method according to any one of claims 1 to 8 in microscopic observation of solid-state batteries.

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