Rubidium ion solid electrolyte, method for preparing same, application thereof, and rubidium atom source device

Abstract

The present application provides a rubidium ion solid electrolyte, a preparation method thereof, an application thereof, and a rubidium atomic source device. The preparation method of the rubidium ion solid electrolyte includes: adjusting the pH value of a solution containing an acid root anion, rubidium ions, and aluminum ions to 3-6, and preparing a wet gel through aging, wherein the molar ratio of rubidium ions to aluminum ions is 1:(5-17); performing heat drying treatment on the wet gel to prepare a gel dry powder; heat-treating the gel dry powder at 1000°C - 1600°C for 30 min - 4.5 h to prepare a powder of the rubidium ion solid electrolyte, and the rubidium ion solid electrolyte is Rb-β-Al2O3; compacting and sintering the powder of the rubidium ion solid electrolyte to prepare the rubidium ion solid electrolyte. The preparation method provided by the present application can prepare an Rb-β-Al2O3 solid electrolyte with very high purity and effectively improve its ionic conductivity.

Description

Technical Field

[0001] The present application relates to the field of solid electrolyte technology, and in particular to a rubidium ion solid electrolyte and a preparation method, application, and rubidium atomic source device thereof. Background Art

[0002] The rubidium ion solid electrolyte Rb-β-Al2O3 is based on the β-phase alumina structure, which is doped with alkali metal cations Rb + It is prepared by the method of β-Al2O3, which realizes the orderly transmission of rubidium ions in the interlayer structure. Its ideal chemical formula is Rb2O·11Al2O3. The remarkable feature of this structure is that the oxygen atoms form a cubic close-packed structure in the ABCA type order. In this structure, the aluminum atoms are located in the gaps between the oxygen atoms, and the tetrahedron and octahedron formed are the basic units of the β-Al2O3 structure; importantly, Rb + Distributed between the layers of these units. Due to its unique advantages in electrochemical properties and stability, Rb-β-Al2O3, as a rubidium ion solid electrolyte, has attracted some attention in rubidium ion batteries and other rubidium ion-driven electrochemical storage systems.

[0003] At present, the method for preparing rubidium ion solid electrolyte Rb-β-Al2O3 is usually solid phase sintering method, which usually needs to be carried out in a high standard inert environment, which is not only demanding, but also complicated and time-consuming. In addition, Rb-β-Al2O3 prepared by this method usually contains more α-Al2O3 impurities, which will seriously affect the transport properties of Rb ions and reduce the ionic conductivity of the solid electrolyte. Summary of the invention

[0004] Based on this, the present application provides a method for preparing a rubidium ion solid electrolyte, which can suppress the generation of α-Al2O3 impurity phase, prepare a very high purity Rb-β-Al2O3 phase, and effectively improve the Rb ion conductivity. In addition, the method is simple in process, cheap in raw materials, and does not require inert environmental protection, and is an economical and efficient preparation method.

[0005] The first aspect of the present application provides a method for preparing a rubidium ion solid electrolyte, comprising:

[0006] The solution containing acid anions, rubidium ions and aluminum ions is adjusted to a pH value of 3-6, and a wet gel is prepared after aging, wherein the molar ratio of the rubidium ions to the aluminum ions is 1:(5-17);

[0007] The wet gel is subjected to heat drying treatment to prepare a gel dry powder;

[0008] Heat-treat the gel dry powder at 1000 °C to 1600 °C for 30 min to 4.5 h to prepare a powder of rubidium ion solid electrolyte, and the rubidium ion solid electrolyte is Rb-β-Al2O3;

[0009] Press and sinter the powder of the rubidium ion solid electrolyte to prepare the rubidium ion solid electrolyte.

[0010] In some embodiments of the present application, at least one of the following conditions is satisfied:

[0011] (1) The molar ratio of the rubidium ion to the aluminum ion is 1:(10 to 15), and can be optionally 1:(10 to 12);

[0012] (2) The acid root anion includes nitrate;

[0013] (3) The temperature of the heat drying treatment is below 90 °C.

[0014] In some embodiments of the present application, at least one of the following conditions is satisfied:

[0015] (1) The temperature of the heat treatment is 1000 °C to 1500 °C, and can be optionally 1000 °C to 1300 °C;

[0016] (2) The time of the heat treatment is 30 min to 4 h, and can be optionally 30 min to 3 h.

[0017] In some embodiments of the present application, the sintering includes one of hot sintering, hot pressing sintering and spark plasma sintering.

[0018] In some embodiments of the present application, the sintering is spark plasma sintering.

[0019] In some embodiments of the present application, at least one of the following conditions is satisfied:

[0020] (1) The temperature of the hot sintering is 1000 °C to 1800 °C, and the time is 30 min to 4 h;

[0021] (2) The temperature of the hot pressing sintering is 1000 °C to 1800 °C, the time is 30 min to 4 h, and the pressure is 10 MPa to 45 MPa;

[0022] (3) The temperature of the spark plasma sintering is 1000 °C to 1500 °C, the time is 5 min to 20 min, and the pressure is 10 MPa to 45 MPa.

[0023] The second aspect of the present application provides a rubidium ion solid electrolyte prepared by the preparation method described in the first aspect of the present application.

[0024] In some embodiments of the present application, at least one of the following conditions is satisfied:

[0025] (1) The purity of the Rb-β-Al2O3 phase in the rubidium ion solid electrolyte is ≥99%;

[0026] (2) The ionic conductivity of the rubidium ion solid electrolyte is ≥10 -7 S / cm.

[0027] The third aspect of the present application provides an application of the rubidium ion solid electrolyte described in the second aspect of the present application in the preparation of a rubidium atomic source device.

[0028] The fourth aspect of the present application provides a rubidium atomic source device, including a first electrode layer, a rubidium ion storage layer, a rubidium ion conduction layer, and a second electrode layer stacked in sequence. The first electrode layer is electrically connected to the second electrode layer. The rubidium ion conduction layer contains the rubidium ion solid electrolyte described in the second aspect of the present application, and the second electrode layer contains pores penetrating through the second electrode layer.

[0029] In the above preparation method provided by the present application, by controlling the molar ratio of rubidium ions to aluminum ions, the pH value of the solution, the temperature and time of heat treatment within their respective corresponding ranges, it is beneficial to produce a cooperation among these conditions; through the cooperation, the formation of α-Al2O3 heterophase can be effectively inhibited and the formation of β-Al2O3 phase can be promoted, improving the purity of the β-Al2O3 phase in the rubidium ion solid electrolyte, so that the obtained rubidium ion solid electrolyte has a very high purity Rb-β-Al2O3 phase. In addition, the process of the above preparation method is simple and does not need to be carried out in an inert environment, and the requirements for the preparation environment are relatively low. Compared with the traditional solid-phase sintering method, the preparation cost can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of a rubidium atomic source device according to an embodiment of the present application.

[0031] Figure 2 It is a Nyquist diagram of the electrochemical impedance spectrum of the rubidium ion solid electrolyte prepared in Example 1.

[0032] Figure 3 It is an X-ray diffraction pattern of the rubidium ion solid electrolyte prepared in Example 1.

[0033] Figure 4 It is a morphology diagram of the rubidium ion solid electrolyte prepared in Example 1.

[0034] Figure 5 It is an X-ray diffraction pattern of Examples 1 to 12.

[0035] Figure 6 X-ray diffraction patterns of Example 1, Examples 13 to 15, and Comparative Examples 1 to 5.

[0036] Description of the drawings: 1 First electrode layer; 2 Rubidium ion storage layer; 3 Rubidium ion conduction layer; 4 Second electrode layer; 5 Control power supply; 6 Rubidium atom. Detailed implementation manners

[0037] To facilitate the understanding of this application, the following will provide a more comprehensive description of this application. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure content of this application more thorough and comprehensive.

[0038] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly recorded; and any lower limit can be combined with other lower limits to form a range not explicitly recorded, and similarly any upper limit can be combined with any other upper limit to form a range not explicitly recorded. In addition, although not explicitly recorded, each point or single value between the range endpoints is included in this range. Thus, each point or single value can be used as its own lower or upper limit and combined with any other point or single value or combined with other lower or upper limits to form a range not explicitly recorded.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. It should be noted that unless otherwise stated, the term "and / or" used herein includes any and all combinations of one or more of the related listed items, "above" and "below" include the recited numbers, and the meaning of "one or more" in "one or more" is two or more.

[0040] The above application content of this application does not intend to describe each disclosed embodiment or each implementation manner of this application. The following description more specifically illustrates exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments, which can be used in various combinations. In each instance, the listing is only as a representative group and should not be construed as exhaustive.

[0041] The first aspect of this application provides a preparation method of a rubidium ion solid electrolyte, which may include the following steps:

[0042] S1. Adjust the pH value of a solution containing an acid radical anion, rubidium ions, and aluminum ions to 3 to 6, and prepare a wet gel after aging, wherein the molar ratio of the rubidium ions to the aluminum ions is 1:(5 to 17);

[0043] S2. Perform heat drying treatment on the wet gel to prepare a dry gel powder.

[0044] S3. Heat-treat the dry gel powder at 1000 °C to 1600 °C for 30 min to 4.5 h to prepare a powder of rubidium ion solid electrolyte, and the rubidium ion solid electrolyte is Rb-β-Al2O3.

[0045] S4. Press and sinter the powder of the rubidium ion solid electrolyte to prepare the rubidium ion solid electrolyte.

[0046] Without intending to be limited by any theory, the inventors found that in the above preparation method provided by the present application, by controlling the molar ratio of rubidium ions to aluminum ions, the pH value of the solution, the temperature and time of heat treatment within their respective corresponding ranges, it is possible to facilitate the cooperation among these conditions. Through this cooperation, the formation of α-Al2O3 impurity phase can be effectively inhibited and the formation of β-Al2O3 phase can be promoted, improving the purity of β-Al2O3 phase in the rubidium ion solid electrolyte, so that the prepared rubidium ion solid electrolyte Rb-β-Al2O3 has a β-Al2O3 phase with very high purity. In addition, the process of the above preparation method is simple and does not need to be carried out in an inert environment, and the requirements for the preparation environment are relatively low. Compared with the traditional solid-phase sintering method, the preparation cost can be greatly reduced.

[0047] Among them, the inventors found that in the crystal lattice structure of β-Al2O3, rubidium ions not only serve as a key component of the conduction layer but also play a role in supporting the crystal lattice structure. When the concentration of rubidium ions is relatively high, it may lead to the formation of complex rubidium oxide compounds in the crystal lattice rather than the expected Rb2O, and this abnormal concentration may hinder the preferential formation of β-Al2O3 phase. On the contrary, when the concentration of rubidium ions is relatively low, it is beneficial to the formation of a more stable α-Al2O3 impurity phase, but it is likely to reduce the lattice stability of the β-Al2O3 phase. Therefore, in the above step S1, controlling the molar ratio of rubidium ions to aluminum ions within the above range can not only reduce the formation of complex rubidium oxide compounds in the crystal lattice due to too high a concentration of rubidium ions, so that more Rb2O is formed in the crystal lattice, reducing the hindrance to the formation of β-Al2O3 phase; but also inhibit the formation of α-Al2O3 phase and improve the lattice stability of β-Al2O3 phase. In this way, it is beneficial to the stable formation of β-Al2O3 phase.

[0048] Meanwhile, the inventors also found that the pH value of the solution has a significant impact on the deposition kinetics of rubidium ions and aluminum ions in the solution, thereby affecting the crystal growth rate and the quality of the final product. A suitable pH environment helps control the ion deposition rate, thereby optimizing the overall quality of the crystal structure and the phase purity. Thus, in the above step S1, after adjusting the pH of the solution to 3 - 6, the solution will contain more cationic positive charges, and the acid radical anions will have Coulomb (electrostatic) interactions with the cationic positive charges, complex through the Coulomb interaction, and form a wet gel containing rubidium ions and aluminum ions.

[0049] In addition, the inventors also found that the temperature and time of heat treatment are key parameters that affect the formation of the β-Al2O3 phase. Too low a temperature may not be sufficient to promote the formation of the β phase, while too high a temperature may cause the evaporation of rubidium elements in the lattice, which not only reduces the purity of the β-Al2O3 phase but also may lead to structural instability and promote the formation of the impurity phase α-Al2O3. Therefore, the temperature and time of heat treatment are crucial for ensuring the purity and stability of the β-Al2O3 phase. Thus, in the above step S3, heat treatment of the gel dry powder under suitable conditions can promote the formation of the β-Al2O3 phase while suppressing the generation of the insulating α-Al2O3 impurity phase, and prepare a rubidium ion solid electrolyte Rb-β-Al2O3 with a very high purity β-Al2O3 phase.

[0050] In some embodiments, in the solution, the molar ratio of rubidium ions to aluminum ions can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17 or within the range composed of any of the above values.

[0051] Controlling the molar ratio of rubidium ions to aluminum ions within the above range can, in combination with other conditions (the pH value of the solution, the temperature and time of heat treatment), make the gel product prepared hardly generate the α-Al2O3 impurity phase during the heat treatment process and facilitate the formation of the β-Al2O3 phase.

[0052] In some embodiments, the molar ratio of the rubidium ions to the aluminum ions is 1:(10 - 15), optionally 1:(10 - 12), and further optionally 1:11.

[0053] In some embodiments, the pH value of the solution can be 3, 3.5, 4, 4.5, 5, 5.5, 6 or within the range composed of any of the above values.

[0054] Controlling the pH value of the solution within the above range can provide the cationic positive charge required for complexation for the formation of the gel, promoting the formation of the gel; meanwhile, it can also cooperate with other conditions (the molar ratio of rubidium ions to aluminum ions, the temperature and time of heat treatment), so that almost no α-Al2O3 impurity phase is formed during the heat treatment of the prepared gel product, and it is beneficial to the formation of the β-Al2O3 phase.

[0055] In some embodiments, the temperature of the heat treatment can be 1000 °C, 1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C, 1600 °C or within the range composed of any of the above values.

[0056] In some embodiments, the temperature of the heat treatment is 1000 °C to 1500 °C, optionally 1000 °C to 1300 °C, and further optionally 1300 °C.

[0057] In some embodiments, the time of the heat treatment can be 30 min, 50 min, 1 h, 2 h, 3 h, 4 h, 4.5 h or within the range composed of any of the above values.

[0058] In some embodiments, the time of the heat treatment is 30 min to 4 h, optionally 30 min to 3 h, and further optionally 2 h.

[0059] Controlling the temperature and time of the heat treatment within the above range can, through cooperation with other conditions (the molar ratio of rubidium ions to aluminum ions, the pH value of the solution), make almost no α-Al2O3 impurity phase formed during the heat treatment of the prepared gel product, and it is beneficial to the formation of the β-Al2O3 phase.

[0060] In some embodiments, the acid radical anion includes nitrate.

[0061] The acid radical anion in the solution can produce Coulomb interaction with the cationic positive charge and produce complexation, thereby promoting the formation of the gel through the complexation between the two.

[0062] In some embodiments, the solution containing acid radical anions, rubidium ions and aluminum ions can be prepared by dissolving rubidium salt and aluminum salt in distilled water.

[0063] Optionally, the rubidium salt includes rubidium nitrate.

[0064] Optionally, the aluminum salt includes aluminum nitrate (nonahydrate, chemical formula Al(NO3)3∙9H2O).

[0065] Selecting rubidium nitrate and aluminum nitrate as the rubidium salt and aluminum salt respectively can not only provide reactants for the formation of the rubidium ion solid electrolyte, but also the cost of rubidium nitrate and aluminum nitrate is relatively lower, which is beneficial to reducing the preparation cost.

[0066] In some embodiments, the pH value of the solution can be adjusted by adding NH4HCO3 to the solution.

[0067] In some embodiments, the temperature of the heat drying treatment is below 90 °C.

[0068] In some embodiments, the sintering includes one of hot sintering, hot press sintering, and spark plasma sintering.

[0069] In some embodiments, the sintering is spark plasma sintering.

[0070] The preparation time of spark plasma sintering is short (such as about 10 min), almost no evaporation of conductive active cations in the raw materials, and the relative density of the prepared rubidium ion solid electrolyte is relatively high, so excellent ionic conduction performance can be obtained.

[0071] In some embodiments, the temperature of the hot sintering is 1000 °C to 1800 °C, and the time is 30 min to 4 h. For example, the temperature of the hot sintering can be 1000 °C, 1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C, 1600 °C, 1700 °C, 1800 °C or within the range composed of any of the above values; the time can be 30 min, 50 min, 1 h, 2 h, 3 h, 4 h, 5 h or within the range composed of any of the above values.

[0072] In some embodiments, the temperature of the hot press sintering is 1000 °C to 1800 °C, the time is 30 min to 4 h, and the pressure is 10 MPa to 45 MPa. For example, the temperature of the hot press sintering can be 1000 °C, 1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C, 1600 °C, 1700 °C, 1800 °C or within the range composed of any of the above values; the time can be 30 min, 50 min, 1 h, 2 h, 3 h, 4 h, 5 h or within the range composed of any of the above values.

[0073] In some embodiments, the temperature of the spark plasma sintering is 1000 °C to 1500 °C, the holding time is 5 min to 20 min, and the pressure is 10 MPa to 45 MPa. For example, the temperature of the spark plasma sintering can be 1000 °C, 1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C or within the range composed of any of the above values; the time can be 5 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min or within the range composed of any of the above values.

[0074] The second aspect of the present application provides a rubidium ion solid electrolyte prepared by the preparation method described in the first aspect of the present application.

[0075] In some embodiments, the purity of the Rb-β-Al2O3 phase in the rubidium ion solid electrolyte is ≥99%. For example, the purity of the Rb-β-Al2O3 phase can be 100%.

[0076] It can be understood that the "purity of the Rb-β-Al2O3 phase" described in the present application refers to the mass ratio of the β-Al2O3 phase in all phases contained in the rubidium ion solid electrolyte.

[0077] In some embodiments, the ionic conductivity of the rubidium ion solid electrolyte is ≥10 -7 S / cm.

[0078] The third aspect of the present application provides an application of the rubidium ion solid electrolyte described in the second aspect of the present application in the preparation of a rubidium atomic source device.

[0079] It can be understood that the "rubidium atomic source device" described in the present application refers to an atomic device using rubidium atoms as the atomic source.

[0080] In some embodiments, the types of rubidium atomic source devices are not limited. For example, they can be rubidium atomic clocks, rubidium atomic oscillators, etc.

[0081] The fourth aspect of the present application provides a rubidium atomic source device, see Figure 1 , which includes a first electrode layer, a rubidium ion storage layer, a rubidium ion conduction layer, and a second electrode layer stacked in sequence. The first electrode layer and the second electrode layer are electrically connected through a control power supply. The rubidium ion conduction layer contains the rubidium ion solid electrolyte described in the second aspect of the present application, and the second electrode layer contains pores penetrating the second electrode layer.

[0082] It can be understood that the "electrical connection" described in the present application means that the first electrode layer and the second electrode layer are connected through the transmission of electrons.

[0083] The rubidium ion solid electrolyte provided by the present application is a pure β-Al2O3 phase, ensuring unobstructed ion channels inside the material, thereby achieving a high rubidium ion conductivity. In the Figure 1 shown rubidium atomic source device, this pure β-Al2O3 phase electrolyte can effectively promote the conversion between neutral rubidium atoms and rubidium ions, realizing the efficient conversion between rubidium atoms and rubidium ions. This conversion is a key link in the device function. This efficient atom-ion conversion directly affects the release or recovery efficiency of rubidium atoms at the active interface of the second electrode layer, which is the core part of the device operation.

[0084] When the device needs to release rubidium atoms, a high-purity electrolyte can accelerate the conversion of rubidium ions into neutral rubidium atoms, thus improving the release efficiency. Conversely, in the recovery mode, the high ionic conductivity in the electrolyte helps to quickly convert neutral rubidium atoms back into rubidium ions, thereby enhancing the recovery efficiency. This rapid and efficient conversion process significantly improves the overall performance of the device, including response speed, efficiency, and stability. Therefore, the rubidium-ion solid electrolyte provided in this application not only performs excellently at the material level but also demonstrates its significant advantages in device applications. The application of this material may promote the further development of rubidium atom device technology, especially in high-performance applications that require efficient ion transport and conversion.

[0085] Example

[0086] The following are specific examples. The following examples more specifically describe the content disclosed in this application. These examples are only for illustrative purposes, as various modifications and changes within the scope of the content disclosed in this application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and all instruments used in the examples are commercially available.

[0087] Example 1

[0088] S1. Prepare a mixed solution of rubidium nitrate and aluminum nitrate with the atomic ratio (i.e., molar ratio) of Rb to Al being 1:11. Use 2 mol / L ammonium bicarbonate to adjust the pH value of the solution to 5.1, and obtain a wet gel after stirring and aging.

[0089] S2. Dry the wet gel at 80 °C for 24 h to obtain a gel dry powder.

[0090] S3. Heat the gel dry powder at 1100 °C for 2 h to obtain Rb-β-Al2O3 powder.

[0091] S4. Pass the Rb-β-Al2O3 powder through a 200-mesh sieve, press it into shape, and then perform spark plasma hot pressing sintering. The sintering temperature is 1300 °C, the pressure is 40 MPa, and the heat preservation time is 15 min to obtain the Rb-β-Al2O3 solid electrolyte. In this solid electrolyte, the purity of the Rb-β-Al2O3 phase is 100%.

[0092] Example 2

[0093] Similar to the preparation process of Example 1, the main difference is that in step S1, the atomic ratio of Rb to Al is 1:5.

[0094] Example 3

[0095] Similar to the preparation process of Example 1, the main difference is that in step S1, the atomic ratio of Rb to Al is 1:12.

[0096] Example 4

[0097] Similar to the preparation process of Example 1, the main difference is that in step S1, the atomic ratio of Rb to Al is 1:15.

[0098] Example 5

[0099] Similar to the preparation process of Example 1, the main difference is that in step S1, the pH value is 3.

[0100] Example 6

[0101] Similar to the preparation process of Example 1, the main difference is that in step S1, the pH value is 6.

[0102] Example 7

[0103] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating temperature is 1000 °C.

[0104] Example 8

[0105] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating temperature is 1300 °C.

[0106] Example 9

[0107] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating temperature is 1500 °C.

[0108] Example 10

[0109] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating time is 30 min.

[0110] Example 11

[0111] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating time is 3 h.

[0112] Example 12

[0113] Similar to the preparation process of Example 1, the main difference is that in step S3, the heating time is 4 h.

[0114] Example 13

[0115] Similar to the preparation process of Example 1, the main difference is that in step S1, the atomic ratio of Rb to Al is 1:17.

[0116] Example 14

[0117] The preparation process is similar to that of Example 1, and the main difference is that: in step S3, the heating temperature is 1600 °C.

[0118] Example 15

[0119] The preparation process is similar to that of Example 1, and the main difference is that: in step S3, the heating time is 4.5 h.

[0120] Comparative Example 1

[0121] The preparation process is similar to that of Example 1, and the main difference is that: in step S1, the atomic ratio of Rb to Al is 1:3.

[0122] Comparative Example 2

[0123] The preparation process is similar to that of Example 1, and the main difference is that: in step S1, the pH value is 2.

[0124] Comparative Example 3

[0125] The preparation process is similar to that of Example 1, and the main difference is that: in step S1, the pH value is 7.

[0126] Comparative Example 4

[0127] The preparation process is similar to that of Example 1, and the main difference is that: in step S3, the heating temperature is 900 °C.

[0128] Comparative Example 5

[0129] The preparation process is similar to that of Example 1, and the main difference is that: in step S3, the heating time is 20 min.

[0130] Comparative Example 6

[0131] The Rb-β-Al2O3 solid electrolyte was prepared by using the traditional solid-phase sintering method, and the preparation method is as follows:

[0132] (1) Hydrated alumina gel Al2O3·nH2O (80 < n < 120) was precipitated from an aqueous solution of Al2(SO4)3 or Al(NO3)3 under the condition of pH ≈ 8.

[0133] (2) The gel was washed to remove anionic contaminants such as sulfates or nitrates.

[0134] (3) The gel was suspended in ethanol containing rubidium hydroxide.

[0135] (4) The reaction flask was equipped with a water-cooled reflux condenser and an alkali protection tube to prevent the entry of carbon dioxide.

[0136] (5) Stir the reaction mixture using a magnetic stirrer in a nitrogen atmosphere and maintain boiling conditions for 6 - 8 hours.

[0137] (6) Wash the obtained solid product to remove the alkali.

[0138] (7) Calcinate the washed product at 1273 - 1473 K to obtain the Rb-β-Al2O3 product.

[0139] Perform relevant performance tests on the Rb-β-Al2O3 solid electrolytes prepared in Examples 1 - 15 and Comparative Examples 1 - 6, and the test results are shown in Table 1 below.

[0140] Among them, the test conditions or test standards for each performance test item are as follows:

[0141] (1) Determine whether the Rb-β-Al2O3 is a pure β-Al2O3 phase

[0142] Test instrument: Malvern Panalytical Empyrean X-ray diffractometer.

[0143] Test conditions: The scanning range is from 5° to 80°, and the scanning rate is 0.02° / s.

[0144] Test method: The characteristic peak analysis of the XRD technique provides a systematic framework to determine the phase purity of the Rb-β-Al2O3 sample. By detecting specific XRD diffraction peaks, we can determine the different alumina phases present in the sample. Since the β’’-Al2O3 phase was not found in any of our products, its characteristic peak positions are: 22.0° (015), 22.9° (009), 27.3° (018), and 34.2° (0111) at 2θ angle respectively. Therefore, the main phases to be concerned about are the β-Al2O3 and α-Al2O3 phases.

[0145] Obtaining theoretical XRD: The theoretical crystal structure of Rb-β-Al2O3 comes from the Materials Project crystal database. In the theoretical crystal structure of Rb-β-Al2O3, Al2O3 is in the β phase and the mobile cation is the Rb ion. Based on the theoretical crystal structure of Rb-β-Al2O3, the theoretical XRD can be calculated to obtain the characteristic peak positions.

[0146] Step 1: Determine the presence of the β-Al2O3 phase

[0147] Characteristic peak positions: at 2θ angles of 7.8° (002), 15.6° (004), 19.9° (012), 31.2° (008), 32.0° (110), 33.1° (107), 35.6° (114), 42.2° (205), 44.4° (206), 57.7° (217), 58.6° (1112), and 66.8° (220) respectively.

[0148] Basis for judgment: If all these characteristic peaks exist, it indicates the presence of β-Al2O3 phase in the sample.

[0149] Step 2: Judgment of the presence of α-Al2O3 phase (PDF#46 - 1212)

[0150] Characteristic peak positions: at 2θ angles of 25.3° (015), 43.0° (113), and 67.6° (030) respectively.

[0151] Basis for judgment: The presence of these characteristic peaks indicates the presence of α-Al2O3 phase in the sample.

[0152] Comprehensive judgment

[0153] Pure phase Rb-β-Al2O3: If only the characteristic peaks in Step 1 exist and the characteristic peaks in Step 2 do not exist, then the sample is pure phase Rb-β-Al2O3.

[0154] Non-Rb-β-Al2O3: If the characteristic peaks in Step 1 do not exist, then the sample is not Rb-β-Al2O3.

[0155] Non-pure phase Rb-β-Al2O3: If in addition to the characteristic peaks in Step 1, the characteristic peaks in Step 2 also exist, then the sample is non-pure phase Rb-β-Al2O3.

[0156] Purity judgment: Based on the ratio of the peak areas of the characteristic peaks corresponding to different phases, the purity of the phase can be judged.

[0157] (2) Ionic conductivity

[0158] Testing instrument: Keysight E4990A impedance analyzer

[0159] Testing conditions: The frequency range is 20 Hz ~ 30 MHz, the testing temperature is 30 °C, and after reaching the set temperature, it is kept constant for 30 min before measurement.

[0160] Testing method: Evenly apply conductive nickel paste on both sides of the Rb-β-Al2O3 solid electrolyte. After curing, apply an alternating current impedance at both ends to conduct the test of ionic conductivity (blocking electrode method).

[0161] Calculation of ionic conductivity: σ = d / (Re × S), where d is the thickness of the sample under test (cm); Re is the bulk impedance of the sample under test (ohm), which can be obtained from the Nyquist plot of the electrochemical impedance spectroscopy ( Figure 2 ) is obtained by the intersection of the semicircle and the oblique line; S is the effective area of ​​the electrode (cm 2 ).

[0162] Table 1

[0163]

[0164] from Figure 3 It can be seen that compared with the XRD of the theoretical perfect crystal of Rb-β-Al2O3, the Rb-β-Al2O3 synthesized in Example 1 has a very good agreement with the theoretical XRD, especially without showing any α-Al2O3 peak, which can prove that the method of the present application can synthesize pure phase Rb-β-Al2O3.

[0165] from Figure 4 (a) and 4 (b) show that the product synthesized in Example 1 has a layered structure, which is consistent with the structure of Rb-β-Al2O3. + transmission channel. Figure 4 The lattice plane spacing in (c) is d = 2.72Å, corresponding to the Miller index (107), which is consistent with the peak of Rb-β-Al2O3 theoretical XRD at 32.8°. Therefore, the lattice fringe information in the SAED pattern and HRTEM pattern is consistent with the XRD results. Figure 4 (d) shows an EDS mapping overlay, including individual element mappings of rubidium (Rb), aluminum (Al), and oxygen (O). The individual elements are evenly distributed without any element aggregation. The above results verify that the material is Rb-β-Al2O3.

[0166] Figure 5 It shows that Examples 2 to 12 are not pure phase Rb-β-Al2O3, and the ionic conductivity is lower than that of Example 1. Figure 6 This indicates that in Comparative Examples 1 to 5, almost no Rb-β-Al2O3 phase is contained.

[0167] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0168] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A preparation method of a rubidium ion solid electrolyte, characterized in that, Comprising: Adjust the pH value of a solution containing an acid radical anion, rubidium ions and aluminum ions to 3 - 6, and prepare a wet gel through aging. Among them, the molar ratio of the rubidium ions to the aluminum ions is 1:(5 - 17), and the pH value of the solution is adjusted by adding NH4HCO3 to the solution; Perform heat drying treatment on the wet gel to prepare a gel dry powder; Heat treat the gel dry powder at 1000°C - 1600°C for 30 min - 4.5 h to prepare a powder of rubidium ion solid electrolyte, and the rubidium ion solid electrolyte includes Rb-β-Al2O3; Press and sinter the powder of the rubidium ion solid electrolyte to prepare the rubidium ion solid electrolyte.

2. The preparation method according to claim 1, characterized in that, Meet at least one of the following conditions: (1) The molar ratio of the rubidium ions to the aluminum ions is 1:(10 - 15); (2) The acid radical anion includes nitrate; (3) The temperature of the heat drying treatment is below 90°C.

3. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of the rubidium ions to the aluminum ions is 1:(10 - 12).

4. The preparation method according to claim 1 or 2, characterized in that Meet at least one of the following conditions: (1) The temperature of the heat treatment is 1000°C - 1500°C; (2) The time of the heat treatment is 30 min - 4 h.

5. The preparation method according to claim 4, wherein Meet one or more of the following conditions: (1) The temperature of the heat treatment is 1000°C - 1300°C; (2) The time of the heat treatment is 30 min - 3 h.

6. The preparation method according to claim 1 or 2, characterized in that, The sintering includes one of hot sintering, hot press sintering and spark plasma sintering.

7. The preparation method according to claim 6, wherein The sintering is spark plasma sintering.

8. The preparation method according to claim 6, characterized in that Meet at least one of the following conditions: (1) The temperature of the hot sintering is 1000°C - 1800°C, and the time is 30 min - 4 h; (2) The temperature of the hot press sintering is 1000°C - 1800°C, the time is 30 min - 4 h, and the pressure is 10 MPa - 45 MPa; (3) The temperature of the spark plasma sintering is 1000°C - 1500°C, the holding time is 5 min - 20 min, and the pressure is 10 MPa - 45 MPa.

9. A rubidium ion solid electrolyte, characterized in that, Obtained by the preparation method according to any one of claims 1 - 8.

10. The rubidium ion solid electrolyte according to claim 9, characterized in that, Meet at least one of the following conditions: (1) The purity of the Rb-β-Al2O3 phase in the rubidium ion solid electrolyte is ≥99%; (2) The ionic conductivity of the rubidium ion solid electrolyte is ≥ 10 -7 S / cm.

11. Use of the rubidium ion solid electrolyte according to claim 9 or 10 in the preparation of a rubidium atomic source device.

12. A rubidium atomic source device, characterized in that, Comprising a first electrode layer, a rubidium ion storage layer, a rubidium ion conduction layer and a second electrode layer which are sequentially stacked. The first electrode layer and the second electrode layer are electrically connected through a control power supply. The rubidium ion conduction layer contains the rubidium ion solid electrolyte according to claim 9 or 10, and the second electrode layer contains pores penetrating through the second electrode layer.

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