Core-shell structured hydrogen anion conductor and preparation method therefor and application thereof

Abstract

A core-shell structured hydrogen anion conductor and a preparation method therefor and an application thereof. The core-shell structured hydrogen anion conductor comprises a core portion and a coating layer, wherein the coating layer coats the core portion. For the core-shell structured hydrogen anion conductor, the core is a mixed ion conductor that conducts hydrogen anions, and the shell is made of a material having high electronic resistance. The conductor exhibits excellent ionic conductivity at room temperature and high temperature, and is expected to be applied to hydrogen anion batteries, fuel cells, electroreduction reaction devices, etc. The conductor greatly broadens the research system and application range of metal hydrides and solid electrolyte materials.

Description

A core-shell structured hydrogen anion conductor and its preparation method and application Technical Field

[0001] The present application relates to a core-shell structured hydrogen anion conductor, a preparation method and an application thereof, and belongs to the field of new energy and solid electrolyte technology. Background Art

[0002] Can conduct Li + 、Na + 、H + , O 2- Various ion conductors of plasma have been widely used in secondary batteries, fuel cells, electrochemical reactions, separation membranes, sensors and other fields. - / H2 has a redox potential as high as -2.3V. Hydrogen ion conductors can be used to construct novel hydrogen ion batteries and fuel cells, and also have the potential to serve as electrolytes for the electrochemical reduction of small molecules (such as CO2 and N2). Several hydrogen ion conductors have been reported, mainly in two categories: one based on alkaline earth metals, including binary hydrides, oxyhydrides, and halogenated hydrogens; the other based on rare earth metals, mainly oxyhydrides and pure hydrides. Research systems for hydrogen ion conductors are still relatively limited, and most systems have poor ionic conductivity at low to medium temperatures and room temperature. Furthermore, because hydrogen ions easily dissociate electrons, the materials often have high electronic conductivity, resulting in a lack of application in the electrochemical field. Achieving high pure hydrogen ion conduction at low to medium temperatures remains a significant challenge.

[0003] The rapid diffusion of hydrogen in rare earth hydrides was discovered as early as the 1990s. Recent studies have shown that the rare earth metal hydride lanthanum hydride can exhibit excellent performance as a hydride ion conductor at both room and low temperatures. However, its operating temperature range is narrow and its thermal stability is poor. Furthermore, the high electronic conductivity of rare earth metal hydrides is not conducive to achieving pure hydride ion conduction. Alkaline earth metal hydrides were shown to be useful as hydride ion conductors as early as the last century, but their operating temperatures are relatively high. While much research has focused on synthesizing new materials, there are fewer reports on the tuning of specialized composite structures to achieve hydride ion conduction.

[0004] Summary of the Invention

[0005] The invention, by constructing a unique core-shell structure, enables it to exhibit excellent hydrogen ion conductivity at both room temperature and low and medium temperatures. This invention will greatly expand the research system and application scope of solid electrolyte materials.

[0006] This invention provides a novel hydrogen ion conductor structure. Specifically, a core-shell microstructured hydrogen ion conductor is constructed, in which the core of the particle is a mixed hydrogen ion conductor and the shell is a high-electronic-resistance material. This conductor exhibits excellent ionic conductivity at both room and elevated temperatures.

[0007] The core material is primarily composed of rare earth metal hydrides, which exhibit excellent hydrogen migration at room temperature and high hydrogen ion conductivity. However, their electronic conductivity is also very high, often on the same order of magnitude as the ionic conductivity or even higher. Therefore, they have previously been unable to be used as hydrogen ion conductors. Our core-shell structure can significantly suppress the electronic conductivity of the core material while retaining considerable hydrogen ion conduction. The cladding material is primarily composed of materials with very low electronic conductivity, preferably insulators, whose electronic conductivity should be at least two orders of magnitude lower than that of the core material, thus suppressing electron transfer in the core. Examples include alkaline (earth) metal hydrides and oxides.

[0008] According to one aspect of the present application, a core-shell structured hydrogen ion conductor is provided, wherein the core-shell structured hydrogen ion conductor comprises a core portion and a coating layer, wherein the coating layer is coated on the core portion;

[0009] The core part is a mixed ion conductor that conducts negative hydrogen ions.

[0010] Optionally, the carriers of the mixed ion conductor are electrons and hydrogen anions, and the ion transfer number thereof is 0.01 to 0.99.

[0011] Optionally, the core portion is a particle with a diameter of 0.01 nm to 1 mm.

[0012] Optionally, the core diameter is selected from any value among 0.01 nm, 0.05 nm, 0.1 nm, 0.5 μm, 1 μm, 5 μm, 10 μm, 100 μm, 1 mm, or a range between any two of the above values.

[0013] Optionally, the coating layer has a thickness of 0.001 nm to 1 mm.

[0014] Optionally, the thickness of the coating layer is selected from any value of 0.001 nm, 0.01 nm, 0.1 nm, 1 nm, 10 nm, 1 μm, 10 μm, 1 mm, or a range between any two of the above values.

[0015] Optionally, the electronic resistivity of the cladding layer at the operating temperature is 100 to 100,000 times that of the core.

[0016] Optionally, the electronic conductivity of the coating layer is 0.001 to 1000 S cm -1 .

[0017] Optionally, the resistivity of the core is 10 -10 ~0.001S cm -1 .

[0018] In this application, a core-shell microstructured hydrogen ion conductor is constructed, in which the particle core of the material is a mixed hydrogen ion conductor and the shell is a material with high electronic resistance; the core size of the heterostructure is 0.01nm~1mm, and the size of the coating layer is 0.001nm~1mm.

[0019] Optionally, the carriers of the mixed ion conductor are electrons and hydrogen anions, and the ion transfer number thereof is 0.01 to 0.99.

[0020] Optionally, within the operating temperature range, the electronic resistivity of the cladding material is more than 100 times the resistivity of the core material.

[0021] Optionally, the covering may be full covering or partial covering.

[0022] Optionally, the core material and the cladding material may be in a single phase, a multi-phase or an amorphous state.

[0023] According to another aspect of the present application, a method for preparing the above-mentioned hydrogen ion conductor is provided, the preparation method comprising:

[0024] A mixture containing a rare earth metal hydride and a main group metal compound is mixed to obtain the core-shell structured hydrogen anion conductor;

[0025] The main group metal compound is an alkali metal compound and / or an alkaline earth metal compound.

[0026] Optionally, the mixed construction method is selected from at least one of ball milling, grinding, wet chemical method, and vapor deposition method.

[0027] Optionally, the ball milling conditions are: a ball milling rotation speed of 50 to 500 rpm, and a ball-to-mass ratio of 1:1 to 100:1.

[0028] Optionally, the ball milling speed is selected from any value of 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm or a range between any two of the above.

[0029] Optionally, the spherical-to-mass ratio is selected from any value of 1:1, 5:1, 10:1, 20:1, 30:1, 50:1, 80:1, 100:1 or a range between any two of the above values.

[0030] Optionally, the ball milling atmosphere has a partial pressure of 0.1 to 100 bar, and the ball milling time is 0.1 to 60 h.

[0031] Optionally, the ball milling atmosphere partial pressure is selected from any value among 0.1 bar, 0.5 bar, 1 bar, 5 bar, 10 bar, 20 bar, 30 bar, 50 bar, 80 bar, 100 bar, or a range between any two of the above values.

[0032] Optionally, the grinding atmosphere is selected from hydrogen and / or argon.

[0033] Optionally, the wet chemical method is carried out under the following conditions: the mixture contains a solvent, and the solvent is selected from at least one of tetrahydrofuran, cyclohexane, and benzene.

[0034] Optionally, the reaction temperature in the wet chemical method is -100 to 900°C.

[0035] Optionally, the reaction temperature in the wet chemical method is selected from any value of -100°C, 0°C, 10°C, 50°C, 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C or a range between any two of the above.

[0036] Optionally, the reaction atmosphere in the wet chemical method is selected from hydrogen and / or argon.

[0037] Optionally, the conditions of the vapor deposition method are: a temperature of -100 to 900° C., and a deposition atmosphere selected from hydrogen and / or argon.

[0038] In the present application, the preparation method of the core-shell structured hydrogen ion conductor comprises the following steps:

[0039] The required raw material powder is constructed into a hydrogen anion conductor powder with a composite core-shell structure through mechanical ball milling, simple grinding and mixing, wet chemical method, vapor deposition and other methods; and the obtained powder is extruded or calcined.

[0040] Optionally, the structure construction method includes at least one of mechanical ball milling, simple grinding and mixing, wet chemical method, vapor deposition, etc.

[0041] Optionally, the method of processing the core-shell structure powder to form a hydrogen anion conductor is extrusion molding or calcination and sintering.

[0042] Optionally, the method of processing the core-shell structure powder to form a hydrogen ion conductor is powder extrusion molding or calcination molding.

[0043] Optionally, the method further comprises installing electrodes at both ends of the extruded or calcined hydrogen ion conductor.

[0044] According to another aspect of the present application, there is provided an application of the core-shell structured hydrogen ion conductor described above in a novel secondary battery, fuel cell, hydrogen separation membrane, sensor, and membrane reactor.

[0045] This application also proposes the use of the aforementioned hydrogen ion conductors in constructing novel secondary batteries, fuel cells, electrochemical reaction devices, hydrogen separation membranes, sensors, and membrane reactors. Specifically, pure rare earth metal binary hydride conductors are used in constructing novel secondary batteries, fuel cells, and electrochemical reaction devices. Mixed metal binary hydride conductors are used in hydrogen separation membranes, sensors, and membrane reactors.

[0046] Hydrogen ion (H - ) has strong reducing properties and high redox potential, is a highly reactive hydrogen source, and is a new type of energy carrier with great development potential. Hydrogen ion conductors have broad application prospects in research fields such as secondary batteries, fuel cells, electrochemical reactions, and hydrogen separation membranes. The present invention proposes a hydrogen ion conductor with a core-shell structure, in which the core is a mixed ion conductor that conducts hydrogen ions, and the shell is a material with relatively large electronic resistance. It exhibits excellent ionic conductivity at room temperature and high temperature, and is expected to be used in hydrogen ion batteries, fuel cells, and electroreduction reaction devices. This invention will greatly broaden the research system and application scope of metal hydrides and solid electrolyte materials.

[0047] The beneficial effects of this application include:

[0048] This application is the first to use a core-shell composite material as a hydrogen ion conductor, broadening the research scope of solid electrolyte systems. The hydrogen ion conductor developed by this method has excellent room temperature and even high temperature conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG1 is a schematic structural diagram of the core-shell structure powder described in Example 1 of the present application.

[0050] FIG2 is a 5 nm electron microscope image of the powder synthesized in Example 1 of the present application and the element distribution of the electron energy loss spectrum.

[0051] FIG3 is a curve showing the change of ionic conductivity with temperature in Example 1 of the present application. DETAILED DESCRIPTION

[0052] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0054] The instrument used in this application is: BioLogic VSP-300 electrochemical workstation.

[0055] The present invention uses a mixed hydrogen ion conductor and a high electronic resistance compound or element as precursors, and synthesizes a hydrogen ion conductor material having a core-shell structure complex as the main material through various physical and chemical methods, and studies the performance and application of the hydrogen ion conductor.

[0056] Example 1

[0057] This embodiment provides a CeH3@BaH2 core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0058] (1) 2 g of CeH3 and 0.648 g of barium hydride were weighed in a glove box and placed in a ball mill. The atmosphere in the ball mill was Ar and the mill was milled for 10 h at a speed of 300 rpm. After running for 10 min, the mill stopped for 2 min and rotated in the opposite direction. The schematic diagram of the powder microstructure is shown in Figure 1, and the electron microscope micrograph and its element distribution are shown in Figure 2. It can be seen from Figure 1 that cerium hydride serves as the core and barium hydride with high electronic resistance serves as the coating layer. It can be seen from Figure 2 that the core-shell structure particles formed are about 10 nm in size, and the main phase is cerium hydride crystals. The corresponding element distribution shows that barium is enriched on the particle surface, while cerium is concentrated in the core.

[0059] (2) Take 400 mg of the reaction product of step (1) and use a hydraulic press to press the powder into a thin sheet with a diameter of 10 mm and a thickness of about 1 mm at a pressure of 100 MPa.

[0060] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were measured using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with measurements taken at 20°C intervals. Each temperature point was kept constant for 2 hours before testing again. The curve of ionic conductivity versus temperature is shown in Figure 3. As can be seen from Figure 3, the sample exhibits good ionic conductivity from room temperature to 240°C.

[0061] Example 2

[0062] This embodiment provides a CeH3@BaO core-shell structure hydrogen ion conductor, the preparation method of which is as follows:

[0063] (1) In a glove box, weigh 2 g of metallic Ce and 0.648 g of barium oxide, place them in a ball mill, fill the mill with 20 bar of H2, and mill for 10 h at 300 rpm. After every 10 min of operation, pause for 2 min and rotate in the opposite direction.

[0064] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0065] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0066] Example 3

[0067] This embodiment provides a CeH3@BaH2 core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0068] (1) In a glove box, weigh 2 g of metallic CeH3 and 0.648 g of barium hydride, place them in a mortar, and grind them by hand for 1 h under an argon atmosphere;

[0069] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0070] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0071] Example 4

[0072] This embodiment provides a LaH3@BaH2 core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0073] (1) In a glove box, 2 g of metallic LaH3 and 0.648 g of barium hydride were weighed, mixed, and placed in THF liquid. The mixture was sealed and shaken for 20 h. The product was filtered and dried under an argon atmosphere.

[0074] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0075] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0076] Example 5

[0077] This embodiment provides a CaH2@BaO core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0078] (1) Using calcium hydride as a substrate in a glove box, barium oxide was deposited onto CaH2;

[0079] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0080] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0081] Example 6

[0082] This embodiment provides a PrH3@MgO core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0083] (1) In a glove box, weigh 2 g of PrH3 and 0.648 g of MgO, place them in a ball mill, and place them in an Ar atmosphere. Mill the mill for 10 h at 300 rpm, stopping for 2 min after every 10 min and rotating in the opposite direction.

[0084] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0085] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0086] Example 7

[0087] This embodiment provides a BaClH@BaH2 core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0088] (1) In a glove box, 3 g of BaClH and 0.648 g of barium hydride were weighed and placed in a ball mill. 20 bar of H2 was then introduced into the mill and the mill was milled for 10 h at 300 rpm. After every 10 min of operation, the mill was stopped for 2 min and rotated in the opposite direction.

[0089] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0090] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 400°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0091] Example 8

[0092] This embodiment provides a BaLiOH@MgO core-shell structure hydrogen anion conductor, the preparation method of which is as follows:

[0093] (1) In a glove box, weigh 2 g of BaLiOH and 0.648 g of MgO, place them in a mortar, and grind them by hand under argon atmosphere for 1 h;

[0094] (2) 400 mg of the reaction product from step (1) was taken and pressed into a sheet with a diameter of 10 mm and a thickness of about 1 mm using a hydraulic press at a pressure of 100 MPa;

[0095] (3) The thin sheet prepared in step (2) was loaded into a stainless steel battery buckle. Nickel foam was used as electrodes on both sides of the thin sheet to increase the contact area and reduce the contact resistance. The impedance spectrum and DC polarization curve of the battery buckle were tested using an electrochemical workstation. The test temperature ranged from 20°C to 260°C, with one point measured every 20°C. Each temperature point was kept constant for 2 hours before testing again.

[0096] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present 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. A core-shell structure hydrogen anion conductor, characterized in that: The core-shell structured hydrogen anion conductor comprises a core portion and a coating layer, wherein the coating layer is coated on the core portion; The core part is a mixed ion conductor that conducts negative hydrogen ions.

2. The hydrogen anion conductor according to claim 1, characterized in that The carriers of the mixed ion conductor are electrons and hydrogen anions, and the ion migration number is 0.01 to 0.

99.

3. The hydrogen anion conductor according to any one of claims 1 to 2, characterized in that The core part is a particle with a diameter of 0.01nm to 1mm; the thickness of the coating layer is 0.001nm to 1mm.

4. The hydrogen anion conductor according to any one of claims 1 to 3, characterized in that The electronic resistivity of the coating layer at the operating temperature is 100 to 100,000 times that of the core.

5. The method for preparing a hydrogen anion conductor according to any one of claims 1 to 4, characterized in that: The preparation method comprises: A mixture containing rare earth metal hydride and main group metal compound is mixed to obtain the core-shell structured hydrogen anion conductor; The main group metal compound is an alkali metal compound and / or an alkaline earth metal compound.

6. The preparation method according to claim 5, characterized in that: The mixed construction method is selected from at least one of ball milling, grinding, wet chemical method, and vapor deposition method.

7. The preparation method according to claim 6, characterized in that: The conditions of the ball milling are as follows: the rotation speed of the ball milling is 50 to 500 rpm, and the ball-mass ratio is 1:1 to 100:

1.

8. The preparation method according to claim 6 or 7, characterized in that: The ball milling atmosphere partial pressure is 0.1 to 100 bar, and the ball milling time is 0.1 to 60 hours.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The grinding atmosphere is selected from hydrogen and / or argon.

10. The preparation method according to any one of claims 6 to 9, characterized in that: The conditions of the wet chemical method are: the mixture contains a solvent, and the solvent is selected from at least one of tetrahydrofuran, cyclohexane, and benzene.

11. The preparation method according to any one of claims 6 to 10, characterized in that: The reaction temperature in the wet chemical method is -100 to 900°C.

12. The preparation method according to any one of claims 6 to 11, characterized in that: The reaction atmosphere in the wet chemical method is selected from hydrogen and / or argon.

13. The preparation method according to any one of claims 6 to 12, characterized in that: The conditions of the vapor deposition method are: the temperature is -100 to 900° C., and the deposition atmosphere is selected from hydrogen and / or argon.

14. Use of the core-shell structured hydrogen anion conductor according to any one of claims 1 to 4 in novel secondary batteries, fuel cells, hydrogen separation membranes, sensors, and membrane reactors.

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