XRD in-situ test auxiliary device and application

Abstract

The invention discloses an XRD (X-Ray Diffraction) in-situ test auxiliary device and application. Comprising a freezing substance source, an unfreezing substance source, a pipeline and a control device, the control device controls the on-off of the pipeline; the frozen substance source and / or the unfrozen substance source are / is connected with the pipeline and are / is led to an XRD in-situ test area through the pipeline. By means of instant freezing of liquid electrolyte on the surface of a sample, long-range disordered molecules are converted into long-range ordered molecules (especially liquid water molecules are converted into solid ice crystals), and the X-ray absorption state of oxygen atoms can be changed. The problem that accurate X-ray maps of most batteries cannot be obtained due to the masking effect of long-range disordered molecules in the in-situ X-ray detection process is solved.

Description

Technical Field

[0001] The present application relates to an XRD in-situ testing auxiliary device and application, belonging to the field of XRD detection instruments. Background Art

[0002] X-ray diffractometers (XRD testing equipment) are usually used to detect the structure and composition of various powder materials in an ex situ manner. The tested samples are usually required to be dried to remove the solvent molecules (water molecules or organic solvent molecules) on the surface. The reason is that if the surface of the tested material is covered by an amorphous liquid film (especially a thin layer of liquid water), the test sensitivity will be seriously reduced.

[0003] Taking the in-situ test process of aqueous batteries as an example, if an in-situ XRD test is required during the battery charging and discharging process, the X-rays will be absorbed by the aqueous electrolyte on the surface of the sample being tested, making it difficult to obtain accurate results for the phase structure analysis of the active material under the electrolyte membrane. When the wavelength range of X-rays is between 2.34nm and 4.4nm (2.34nm corresponds to the K absorption band of oxygen atoms, and 4.4nm corresponds to the K absorption band of carbon atoms), X-rays will not be absorbed by water molecules, that is, water is transparent to X-rays. This X-ray wavelength range is called the "water window". However, the KαX-ray wavelength generated by the copper target commonly used in X-ray diffractometers is 0.154056nm, which is much smaller than 2.34nm. X-rays of this wavelength will be absorbed by oxygen atoms in amorphous (liquid) water molecules, and other commonly used types of targets cannot produce X-rays with wavelengths within the "water window" range. This seriously hinders the in-situ X-ray diffraction test and analysis of aqueous batteries.

[0004] In order to reduce the impact of liquid film coverage on the sample surface on in-situ XRD testing, some researchers have used the method of closely attaching a film (resin film or glass film) to the electrode surface for testing. These methods can only reduce the thickness of the water film to a certain extent, and cannot offset the absorption of X-rays by liquid water molecules. In addition, the material composition of the surface film also has a certain impact on the XRD test results. Therefore, this type of solution is not the best solution to the above problem. Summary of the invention

[0005] The present invention proposes an X-ray diffractometer in-situ test auxiliary device, which is characterized in that it can spray cooling gas or cooling liquid (or ultra-low temperature gas or liquid) onto the target surface to achieve the purpose of instantaneously freezing the liquid aqueous solution on the surface of the sample to be tested, and then spray normal temperature or high temperature gas from the same nozzle or different nozzles to achieve the purpose of quickly thawing the sample surface, so that the sample to be tested can be restored to the temperature before cooling in the shortest time. The designed device has an instantaneous temperature measurement function and a gas or liquid injection flow control function, the purpose of which is to detect the temperature of the surface of the sample to be tested before freezing and the temperature change during the heating and thawing process, and control the ejection amount of the ultra-low temperature gas or liquid and the thawing gas accordingly. In addition, the designed auxiliary device is equipped with a programmable intelligent control module, which can realize intelligent control of the injection time, injection interval, injection flow, and the sample surface temperature before and after injection, and the intelligent control system can communicate with other instruments and equipment through an adapter. The designed device converts long-range disordered molecules into long-range ordered molecules (especially liquid water molecules into solid ice crystals) by instantaneously freezing the liquid electrolyte on the sample surface, thereby changing the absorption state of oxygen atoms to X-rays, thereby solving the problem that most batteries cannot obtain accurate X-ray spectra during in-situ X-ray detection due to the masking effect of the long-range disordered electrolyte.

[0006] According to one aspect of the present application, there is provided an XRD in-situ test auxiliary device, comprising a frozen material source, a thawed material source, a pipeline, and a control device;

[0007] The control device controls the on-off of the pipeline;

[0008] The frozen material source and / or the thawed material source are connected to the pipeline and lead to the XRD in-situ testing area through the pipeline.

[0009] The frozen substance source and the thawed substance source are connected to the same gas pipeline.

[0010] The pipeline includes pipeline I and pipeline II;

[0011] The freezing material source is connected to one of pipeline I and pipeline II;

[0012] The thawing material source is connected to the other one of pipeline I and pipeline II;

[0013] The control device uniformly controls the on and off of pipelines I and II.

[0014] The control device includes electronic control and / or manual control.

[0015] The control device is connected with the control system of XRD to achieve unified control.

[0016] The control device comprises a temperature detection device, which can detect the temperature of the surface of the sample located in the XRD in-situ test area.

[0017] The XRD in-situ test auxiliary device comprises a fixing device;

[0018] The fixing device fixes the pipeline.

[0019] According to another aspect of the present application, an XRD in-situ testing method is provided, using the above-mentioned XRD in-situ testing auxiliary device;

[0020] The following steps are involved:

[0021] The sample is placed in the XRD in-situ test area, and a freezing material is sprayed onto the sample surface to instantly freeze the solution on the sample surface for testing. Subsequently, a thawing material is sprayed onto the sample surface to thaw and recover the solution on the sample surface.

[0022] The freezing substance is selected from liquid nitrogen.

[0023] The temperature of the freezing material can be slightly lower than the freezing point of the solution on the sample surface.

[0024] The temperature of the thawed material is 25-30°C.

[0025] The frozen material and the thawed material are both selected to be non-contaminating to the sample.

[0026] The beneficial effects of this application include:

[0027] The present invention proposes an X-ray diffractometer in-situ test auxiliary device, which is characterized in that cooling gas or cooling liquid (or ultra-low temperature gas or liquid) can be sprayed onto the target surface to achieve the purpose of instantaneous freezing of the liquid aqueous solution on the surface of the sample to be tested, and then normal temperature or high temperature gas can be sprayed from the same nozzle or different nozzles to achieve the purpose of rapid thawing of the sample surface, so that the sample to be tested can be restored to the temperature before cooling in the shortest time.

[0028] The designed device has instantaneous temperature measurement function and gas or liquid injection flow control function. The purpose is to detect the temperature of the surface of the sample before freezing and the temperature change during the heating and thawing process, and control the injection amount of ultra-low temperature gas or liquid and thawing gas accordingly.

[0029] In addition, the designed auxiliary device is equipped with a programmable intelligent control module, which can realize intelligent control of the injection time, injection interval, injection flow rate, and sample surface temperature before and after injection, and the intelligent control system can communicate with other instruments and equipment through an adapter.

[0030] The designed device can change the absorption state of oxygen atoms to X-rays by instantly freezing the liquid electrolyte on the surface of the sample, thereby converting the long-range disordered molecules into long-range ordered molecules (especially liquid water molecules into solid ice crystals). This solves the problem that most batteries cannot obtain accurate X-ray spectra during in-situ X-ray detection due to the masking effect of long-range disordered molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of device example 1 of the present application.

[0032] Figure 2 This is a schematic diagram of device example 2 of the present application.

[0033] Figure 3 The following are the test results of the XRD test in Example 1.

[0034] Figure 4 This is the test result of the XRD test in Example 2.

[0035] Figure 5 This is the test result of the XRD test in Example 3.

[0036] Figure 6 The following are the test results of the XRD test in Comparative Example 1.

[0037] Figure 7 This is the test result of the XRD test in Comparative Example 4.

[0038] Figure 8 This is the test result of the XRD test in Comparative Example 5.

[0039] The list of parts and reference numerals is as follows:

[0040] 1. Communication cable; 2. Power cord; 3. Control system;

[0041] 4. Valve I; 5. Valve II; 6. Temperature sensor;

[0042] 7. Temperature sensor; 8. Pipeline I; 9. Pipeline II;

[0043] 10. Fixing device; 11. X-ray emitting device; 12. X-ray receiving device;

[0044] 13. Battery sample to be tested; 14. In-situ test area; 15. Battery positive electrode;

[0045] 16. Negative pole of the battery. DETAILED DESCRIPTION

[0046] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0047] Device example 1

[0048] An XRD in-situ test auxiliary device, Figure 1 This is a schematic diagram of the device example 1 of the present application. It includes 1. communication cable; 2. power line; 3. control system; 4. valve I; 5. valve II; 6. temperature sensor; 7. temperature sensor; 8. pipeline I; 9. pipeline II; 10. fixing device; 11. X-ray emitting device; 12. X-ray receiving device; 13. battery sample to be tested; 14. in-situ test area; 15. battery positive electrode; 16. battery negative electrode.

[0049] 1. Communication cable and 2. Power cable are connected to 3. Control system.

[0050] 3. The control system controls 4. Valve I, 5. Valve II, 6. Temperature sensor, 7. Temperature sensor, 11. X-ray transmitting device, 12. X-ray receiving device, and is connected thereto.

[0051] 4. Valve I controls the on / off of pipeline II;

[0052] 5. Valve II controls the on / off of pipeline I;

[0053] Among them, 8. Pipeline I is the passage for frozen materials; 9. Pipeline II is the passage for thawed materials.

[0054] Device example 2

[0055] Device Example 2 is attached Figure 1 Another variation of the dotted line portion, where 8, pipeline I and 9, pipeline II are merged into one pipeline, and the rest are the same.

[0056] The following examples are all carried out using the apparatus described in Apparatus Example 1.

[0057] The sample to be tested may be any undried powder material or electrode material with a liquid film on the surface or diaphragm material with a liquid film on the surface. The electrode material with a liquid film on the surface refers to an aqueous battery electrode material or an organic battery electrode material. The aqueous battery electrode material refers to the positive or negative electrode material of lead-acid batteries, lead-carbon batteries, zinc ion batteries, flow batteries, etc. The organic battery electrode material refers to the positive or negative electrode material of lithium ion batteries, sodium ion batteries, magnesium ion batteries, potassium ion batteries, etc.

[0058] During the test, the designed equipment is used in conjunction with the electrochemical test equipment and XRD equipment to condense and thaw the surface of the tested sample.

[0059] The coordination method refers to that during the operation of the electrochemical testing equipment, the XRD equipment scans and tests the sample according to a designed program, measures the temperature and sprays the surface of the sample within 0.1s-1000min before the XRD equipment is started, and sprays low-temperature gas or low-temperature liquid that can be instantly vaporized; during the XRD equipment test, continuously sprays low-temperature gas or low-temperature liquid that can be instantly vaporized to ensure that the liquid film on the surface of the sample is in a solidified state; 0.1s-1000min after the end of the current XRD test cycle, spray normal temperature or heated gas on the surface of the sample until the surface temperature of the sample is consistent with the surface temperature before spraying the low-temperature gas.

[0060] Among them, low-temperature gas or low-temperature liquid that can be vaporized instantly refers to gaseous substances at normal temperature and pressure with a boiling point below 0 degrees Celsius, mainly including nitrogen, carbon dioxide, oxygen, argon, etc.

[0061] After a cycle of XRD testing is completed, the normal temperature or heated gas sprayed to restore the sample to its original temperature is one or a combination of various component gases in the air.

[0062] Example 1

[0063] Turn on the power to test the active material of the lead-carbon battery electrode.

[0064] The preparation method of the battery is:

[0065] 1) Preparation of negative electrode: (1) Premix 600g lead powder, 9g activated carbon, 8.4g barium sulfate, and 0.3g polypropylene short fibers with a length of 5mm and a diameter of 0.5-1.5μm in a high-speed mixer, add 84g deionized water to the premixed powder while stirring, and continue stirring for 10 minutes to obtain lead paste; (2) Scrape the lead paste onto a metal lead grid with a size of 70mm long, 50mm wide, and 2mm thick, and cure and dry to obtain a lead-carbon battery negative electrode. The curing temperature is 40°C, the humidity is 80%, and the curing time is 20 hours; the drying temperature is 80°C, and the time is 24 hours;

[0066] 2) Preparation of the positive electrode: The positive electrode of the lead-acid battery is prepared according to the same process steps as the negative electrode preparation steps (1) and (2), except that no carbon material is added to the positive electrode;

[0067] 3) Preparation of lead-carbon battery: three positive plates and two negative plates are placed in parallel with each other in an alternating manner, and a colloidal PE separator for lead-carbon battery is placed between the positive plates and the negative plates, and two negative plates are welded in parallel and three positive plates are welded in parallel respectively. The total mass of positive active material of the lead-acid battery (the total mass of the lead paste on the three positive plates after drying) is 60.0g, and the total mass of positive active material refers to the total mass of the lead paste contained in the three positive plates welded in parallel. The total mass of negative active material (the total mass of the lead paste on the two negative plates after drying) is 52.9g, and the total mass of negative active material refers to the total mass of the lead paste contained in the two negative plates welded in parallel. The positive and negative electrode grids are conventional lead grids with dimensions of 70 mm long, 50 mm wide and 2 mm thick. The positive and negative electrodes are placed in a tightly assembled battery box with a length of 76 mm, a width of 40 mm and a height of 100 mm. 83 g of sulfuric acid electrolyte with a density of 1.275 g / ml is injected into the battery box.

[0068] 4) The battery is subjected to the formation step by the commonly used industrial formation method, and then a through hole is cut on the shell surface of the battery with a length of 76 mm and a width of 40 mm. During the cutting process, it should be ensured that there is no damage to the internal electrode material. The through hole size requirement can ensure that the temperature sensor and gas injection hole of the designed X-ray diffractometer in-situ test auxiliary device can normally realize the designed functions, and the X-ray can be perfectly absorbed by the active material surface. In this embodiment, its size is 30 mm long and 20 mm wide.

[0069] Correctly connect the positive and negative electrodes of the battery to the blue electricity tester and perform a 10-hour constant current charge and discharge test on the battery. The discharge current is set to 0.52A, the discharge time is 10 hours, and the charging current is 0.52A for 10 hours. During the charge and discharge process, a 10-minute standby step is set every 1 hour. Set the XRD tester and the designed X-ray diffractometer in-situ test auxiliary device. Turn on the designed X-ray diffractometer in-situ test auxiliary device 5s after the battery enters the standby state, and measure the temperature and spray liquid nitrogen at the battery opening. When the electrode surface temperature reaches -5°C, turn on the XRD tester, and set the XRD equipment to complete the test within 5 minutes. Then spray room temperature nitrogen to the battery opening and monitor the surface temperature until its surface temperature reaches the temperature before cooling. Repeat this process many times until the battery in-situ XRD test is completed.

[0070] Figure 3 The test results of XRD test on the negative electrode surface of the lead-carbon battery during the first storage process of the battery under the above test conditions are compared with the test results of Comparative Example 1 without turning on the in-situ test auxiliary device of the X-ray diffractometer. The test of this embodiment obtained a clear X-ray diffraction spectrum with obvious peaks.

[0071] Example 2

[0072] According to the same requirements as in Example 1, without changing other conditions, the lead-carbon battery was replaced by a zinc-ion battery, and the conventional preparation method of zinc-ion batteries reported in the literature was used to assemble and test the battery.

[0073] Figure 4 This is the XRD test result curve of the negative electrode active material when the battery is placed for the first time under the test conditions, compared with the test results of Example 4 without turning on the X-ray diffractometer in-situ test auxiliary device. The test of this embodiment obtained a clear X-ray diffraction spectrum with obvious peaks.

[0074] Example 3

[0075] According to the same requirements as in Example 1, without changing other conditions, the lead-carbon battery is replaced by a lithium-ion battery, and the conventional preparation method of lithium titanate lithium-ion battery reported in the literature is used to assemble and test the battery. Before the in-situ test begins, the environment around the tested battery is filled with inert gas, and the corresponding test is performed.

[0076] Figure 5 3 is the XRD test result curve of the negative electrode active material when the battery is placed for the first time under the test conditions, compared with the test results of Example 5 without turning on the in-situ test auxiliary device of the X-ray diffractometer. The test of this embodiment obtains a clear X-ray diffraction spectrum with obvious peaks.

[0077] Comparative Example 1

[0078] According to the same requirements as in Example 1, other conditions are not changed, and the designed X-ray diffractometer in-situ test auxiliary device is not turned on. The test results are plotted as follows: Figure 6 curve.

[0079] Due to the presence of electrolyte on the surface of the active material of the lead-carbon battery during the in-situ XRD test, a large amount of X-rays are absorbed by water molecules, resulting in the diffraction peaks of each active material in the test result curve not being obvious, and it is impossible to analyze the crystallization state of each active material in the battery and the changes in the crystallization state of the active material under different charge and discharge depths of the battery.

[0080] Comparative Example 2

[0081] According to the same requirements as in Example 1, other conditions were not changed, and the temperature sensor of the designed X-ray diffractometer in-situ test auxiliary device was not turned on. Since the battery surface temperature could not be restored to the original temperature, the test could not be completed normally.

[0082] Comparative Example 3

[0083] According to the same requirements as in Example 1, other conditions were not changed, the normal temperature gas injection module of the designed X-ray diffractometer in-situ test auxiliary device was not turned on, and normal temperature nitrogen was not sprayed on the sample surface after the test. Since the battery surface temperature took too long to return to normal temperature, the test could not be completed normally.

[0084] Comparative Example 4

[0085] According to the same requirements as in Example 2, without changing other conditions and without turning on the designed X-ray diffractometer in-situ test auxiliary device, the test results are plotted as Figure 7 curve.

[0086] Due to the presence of electrolyte on the surface of the negative electrode active material of the zinc ion battery during the in-situ XRD test, a large amount of X-rays are absorbed by water molecules, resulting in the diffraction peaks of each active material in the test result curve not being obvious, and it is impossible to analyze the crystallization state of each active material in the battery and the changes in the crystallization state of the active material under different charge and discharge depth conditions of the battery.

[0087] Comparative Example 5

[0088] According to the same requirements as in Example 3, without changing other conditions and without turning on the designed X-ray diffractometer in-situ test auxiliary device, the test results are plotted as Figure 8 curve.

[0089] Due to the presence of electrolyte on the surface of the negative electrode active material of the lithium titanate battery during the in-situ XRD test, a large amount of X-rays are absorbed by water molecules, resulting in the diffraction peaks of each active material in the test result curve not being obvious, and it is impossible to analyze the crystallization state of each active material in the battery and the changes in the crystallization state of the active material under different charge and discharge depths of the battery.

[0090] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An XRD in-situ test auxiliary device, characterized in that: Including frozen material source, thawed material source, pipelines, and control devices; The control device controls the on-off of the pipeline; The frozen material source and / or the thawed material source are connected to the pipeline and lead to the XRD in-situ testing area through the pipeline.

2. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The frozen substance source and the thawed substance source are connected to the same gas pipeline.

3. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The pipeline includes pipeline I and pipeline II; The freezing material source is connected to one of pipeline I and pipeline II; The thawing material source is connected to the other one of pipeline I and pipeline II; The control device uniformly controls the on and off of pipelines I and II.

4. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The control device includes electronic control and / or manual control.

5. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The control device is connected to the control system of XRD for unified control.

6. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The control device comprises a temperature detection device for detecting the temperature of the surface of the sample located in the XRD in-situ test area.

7. The XRD in-situ test auxiliary device according to claim 1, characterized in that: The XRD in-situ test auxiliary device comprises a fixing device; The fixing device fixes the pipeline.

8. An XRD in-situ testing method, characterized in that: An XRD in-situ test auxiliary device as claimed in any one of claims 1 to 7; The following steps are involved: The sample is placed in the XRD in-situ test area, and a freezing material is sprayed onto the sample surface to instantly freeze the solution on the sample surface for testing. Subsequently, a thawing material is sprayed onto the sample surface to thaw and recover the solution on the sample surface.

9. The method according to claim 8, characterized in that The freezing substance is selected from liquid nitrogen.

10. The method according to claim 8, characterized in that The temperature of the thawed material is 25-30°C.

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