A magnesium-based anode for constructing a rare earth hydride dispersion structure in situ by hydrogenation and a preparation method and application thereof

Abstract

This invention provides a magnesium-based anode with an in-situ hydrogenation-constructed rare-earth hydride dispersion structure, its preparation method, and its application, belonging to the field of metallic materials technology. The magnesium-based anode comprises a magnesium matrix and a rare-earth hydride phase distributed within the magnesium matrix; wherein the rare-earth hydride phase is formed by in-situ hydrogenation of a magnesium-based alloy containing rare-earth elements, and the rare-earth hydride phase is dispersed within the magnesium matrix or at the interface, forming a rare-earth hydride / magnesium composite structure. The magnesium-based anode of this invention maintains good output performance under high current density conditions, making it suitable for applications such as high-power magnesium-air batteries.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, and in particular to a magnesium-based anode with an in-situ hydrogenation structure for constructing a rare earth hydride dispersion, its preparation method, and its application. Background Technology

[0002] Metal-air batteries are considered a promising chemical power source system due to their high theoretical energy density, abundant raw material sources, and environmental friendliness. Among them, magnesium-air batteries, using magnesium metal as the anode, are characterized by abundant resources, low cost, high safety, and the ability to operate in aqueous electrolytes, demonstrating potential application value in emergency power supplies, marine equipment, power supply security, and distributed energy.

[0003] However, in practical applications, the output performance and operational stability of magnesium-air batteries are largely limited by the reaction behavior of the magnesium-based anode material. In existing technologies, magnesium anodes are prone to self-corrosion in aqueous or chloride-containing electrolyte environments, accompanied by hydrogen evolution and the generation of corrosion products, leading to a reduction in the effective discharge reaction ratio. Simultaneously, under higher discharge current densities, the anode surface is susceptible to uneven reaction, localized rapid consumption, and corrosion product accumulation, resulting in rapid voltage decay and limiting the application of magnesium-air batteries under high-power output conditions.

[0004] To improve the discharge performance of magnesium-based anodes, existing research typically employs alloying, heat treatment, or plastic deformation to introduce a second phase or regulate the microstructure to influence magnesium dissolution behavior. For example, adding alloying elements to form intermetallic compound phases or altering the precipitation state and distribution morphology of the second phase through heat treatment can improve the anode's reactivity to some extent. However, these methods still have limitations in practical applications, such as difficulty in precisely controlling the distribution of the second phase, localized reaction concentration, and insufficient stability under high current conditions. Furthermore, rare earth elements, due to their unique metallurgical properties, have been extensively studied in magnesium alloys. Some rare earth elements can form intermetallic compounds with magnesium, affecting the microstructure and corrosion behavior of magnesium-based materials. However, in current technologies, rare earth elements typically exist as alloying elements or second phases, and their role in the electrochemical reaction process still mainly relies on static structural regulation, making it difficult to continuously adjust the reaction behavior at the anode interface during discharge.

[0005] Therefore, how to effectively control the microstructure and reaction behavior of magnesium-based anodes without significantly increasing material complexity and preparation costs, and improve their discharge uniformity and operational stability under high current density conditions, remains a pressing technical problem to be solved in the field of magnesium-air batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a magnesium-based anode with an in-situ hydrogenation structure for constructing a rare earth hydride dispersion, its preparation method, and its application, in order to solve the problems of uneven reaction, severe self-corrosion, and insufficient output voltage and stability under high current density conditions in existing magnesium-based anodes in magnesium-air batteries.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a magnesium-based anode with an in-situ hydrogenation structure for constructing a rare earth hydride dispersion, the magnesium-based anode comprising a magnesium matrix and a rare earth hydride phase distributed in the magnesium matrix; The rare earth hydride phase is formed by in-situ hydrogenation of a magnesium-based alloy containing rare earth elements. The rare earth hydride phase is dispersed in the interior or interface region of the magnesium matrix to form a rare earth hydride / magnesium composite structure.

[0008] Furthermore, the rare earth elements include one or more of cerium, lanthanum, praseodymium, neodymium, samarium, and yttrium.

[0009] Furthermore, the magnesium-based alloy containing rare earth elements is a magnesium-rare earth binary alloy or a multi-element magnesium-based alloy containing other alloying elements.

[0010] Furthermore, the rare earth hydride phase is a nano- or submicron-sized particle, an island structure, or a continuous network structure.

[0011] Furthermore, the dispersion method is a discontinuous or semi-continuous dispersion distribution method.

[0012] This invention also provides a method for preparing a magnesium-based anode with an in-situ hydrogenation structure of rare earth hydrides, comprising the following steps: In-situ hydrogenation treatment of magnesium-based alloys containing rare earth elements allows for the selective hydrogenation of rare earth elements, forming rare earth hydride phases, thus yielding magnesium-based anodes.

[0013] Furthermore, the in-situ hydrogenation process is carried out in a hydrogen atmosphere or a hydrogen-containing environment.

[0014] Furthermore, the in-situ hydrogenation treatment is as follows: first, pre-activate in a hydrogen environment at 150~250℃ for 1~3h; then raise the temperature to 350~450℃ and dehydrogenate under vacuum for 0.5~1.5h, repeat several times, and then cool down to 100~200℃ for hydrogenation for 12~36h.

[0015] This invention also provides the application of a magnesium-based anode with an in-situ hydrogenated rare-earth hydride dispersion structure in a metal-air battery.

[0016] Furthermore, the metal-air battery is a magnesium-air battery, a magnesium-seawater battery, or a magnesium-silver halide battery.

[0017] The beneficial effects of this invention are: (1) By constructing a rare earth hydride dispersion structure inside the magnesium matrix through in-situ hydrogenation, the reaction uniformity of the magnesium-based anode is effectively improved and the risk of local reaction concentration is reduced. (2) The rare earth hydride phase exists stably in the magnesium matrix, which helps to improve the working stability of the anode during the discharge process and slow down the voltage decay; (3) The magnesium-based anode can still maintain good output performance under high current density conditions, and is suitable for high-power magnesium-air batteries and other application scenarios; (4) The preparation method of the present invention is simple and highly controllable, applicable to a variety of rare earth magnesium-based materials, and has good engineering application prospects. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the effect of the in-situ hydrogenation technology solution of the present invention; Figure 2 Backscattered images of the Mg-RE alloy (Mg3Ce alloy) before and after hydrogenation; Figure 3 The discharge voltage and energy density curves of magnesium-air batteries assembled from samples before and after hydrogenation are shown. Figure 4 The discharge voltage-time curves of the seawater-activated battery assembled from samples before and after hydrogenation are shown. Detailed Implementation

[0019] This invention provides a magnesium-based anode with an in-situ hydrogenation structure for constructing a rare earth hydride dispersion, the magnesium-based anode comprising a magnesium matrix and a rare earth hydride phase distributed in the magnesium matrix; The rare earth hydride phase is formed by in-situ hydrogenation of a magnesium-based alloy containing rare earth elements. The rare earth hydride phase is dispersed in the interior or interface region of the magnesium matrix to form a rare earth hydride / magnesium composite structure.

[0020] In this invention, the rare earth element comprises one or more of cerium, lanthanum, praseodymium, neodymium, samarium, and yttrium, preferably one or more of cerium, lanthanum, and praseodymium.

[0021] In this invention, the magnesium-based alloy containing rare earth elements is a magnesium-rare earth binary alloy or a multi-element magnesium-based alloy containing other alloying elements, preferably a magnesium-rare earth binary alloy.

[0022] The magnesium-based material described in this invention can be any magnesium or magnesium alloy material containing rare earth elements. The rare earth elements are not limited to a single element, but can be a combination of one or more rare earth elements. The rare earth elements in the magnesium-based material can exist in a solid solution state, an intermetallic compound state, or other forms, as long as they can undergo a hydrogenation reaction under hydrogenation conditions to form rare earth hydrides.

[0023] In this invention, the rare earth hydride phase is nano- or submicron-sized particles, island structure, or continuous network structure, preferably a continuous network structure.

[0024] In this invention, the dispersion method is a discontinuous or semi-continuous dispersion distribution method, preferably a semi-continuous dispersion distribution method.

[0025] This invention also provides a method for preparing a magnesium-based anode with an in-situ hydrogenation structure of rare earth hydrides, comprising the following steps: In-situ hydrogenation treatment of magnesium-based alloys containing rare earth elements allows for the selective hydrogenation of rare earth elements, forming rare earth hydride phases, thus yielding magnesium-based anodes.

[0026] In this invention, the in-situ hydrogenation treatment is carried out in a hydrogen atmosphere or a hydrogen-containing environment.

[0027] In this invention, the in-situ hydrogenation treatment is as follows: first, pre-activate in a hydrogen atmosphere at 150~250℃ for 1~3h; then raise the temperature to 350~450℃ and dehydrogenate under vacuum for 0.5~1.5h, repeating this process several times, and then cool down to 100~200℃ for hydrogenation for 12~36h; preferably, first, pre-activate in a hydrogen atmosphere at 200℃ for 2h; then raise the temperature to 400℃ and dehydrogenate under vacuum for 0.5h, repeating this process twice, and then cool down to 100℃ for hydrogenation for 24h.

[0028] In this invention, the in-situ hydrogenation process can be carried out in a closed reaction environment. By controlling the hydrogen pressure, reaction temperature, and reaction time, rare earth elements undergo hydrogenation within the magnesium matrix. By rationally controlling the hydrogenation parameters, the generated rare earth hydrides can be dispersed in the magnesium matrix in a particulate or near-particulate form, avoiding the formation of a continuous phase or locally enriched structures. The magnesium-based anode material after in-situ hydrogenation maintains the overall structural integrity of the magnesium matrix while constructing a dispersed rare earth hydride structure within it. This structure can remain stable for a long period during the electrochemical reaction, resulting in uniform reaction characteristics of the anode during discharge, suitable for energy output under high discharge current density conditions.

[0029] In this invention, unlike existing methods that form a second phase through surface coating, external introduction, or post-treatment modification, the rare earth hydride phase is generated in situ inside the magnesium-based material. Its formation process is coupled with the material's bulk structure, and the resulting rare earth hydride phase has a stable interfacial bonding relationship with the magnesium matrix, which is beneficial for maintaining structural stability during the electrochemical reaction process.

[0030] This invention also provides the application of a magnesium-based anode with an in-situ hydrogenated rare-earth hydride dispersion structure in a metal-air battery.

[0031] In this invention, the metal-air battery is a magnesium-air battery, a magnesium-seawater battery, or a magnesium-silver halide battery, and the magnesium-based anode with an in-situ hydrogenated rare earth hydride dispersion structure is used as the anode material in the metal-air battery.

[0032] The magnesium-based anode material described in this invention can be used as the anode material in magnesium-air batteries, seawater-activated batteries, or other electrochemical energy conversion devices using magnesium as the active material. Its application is not limited to single-electrode use; it can also be used in combination with different types of air cathodes or other cathode materials.

[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a method for preparing a magnesium-based anode material, including the following steps: Single-phase Mg3Ce magnesium-based alloy was selected as the raw material. The alloy was placed in a sealed, controlled atmosphere reaction vessel. After evacuation, high-purity hydrogen gas (>99.999%) at 0.2 MPa was introduced, and pre-activation was performed at 200°C for 2 hours. Then, dehydrogenation was carried out under vacuum at 400°C for half an hour. This process was repeated twice. Finally, hydrogenation was performed at 100°C and 0.1 MPa for 24 hours to obtain the hydrogenated sample. By controlling the reaction temperature within the range where rare earth elements preferentially undergo hydrogenation without significant structural damage to the magnesium matrix, and maintaining this temperature for a certain period, rare earth elements preferentially react with hydrogen, generating rare earth hydride phases in situ within the magnesium matrix.

[0036] After the in-situ hydrogenation treatment, the rare earth hydrides are dispersed in the magnesium matrix in a particulate or near-particulate form, forming a two-phase composite structure composed of the magnesium matrix and rare earth hydrides. The rare earth hydride phase exhibits a discontinuous and non-connected dispersed distribution within the magnesium matrix. Backscattering images before and after hydrogenation are shown below. Figure 2 As shown.

[0037] The above method can be used to obtain a magnesium-based anode material with a rare earth hydride dispersion structure inside.

[0038] Example 2

[0039] Same as Example 1, except that the processing conditions are as follows: after vacuuming, high-purity hydrogen gas with a purity of >99.999% is introduced at 0.2 MPa, pre-activated at 150°C for 3 hours, and then dehydrogenated under vacuum at 400°C for half an hour. This process is repeated twice, and then hydrogenated at 100°C and 0.1 MPa for 24 hours to obtain the hydrogenated sample.

[0040] Example 3

[0041] The magnesium-based anode material prepared in Example 1 was used as the anode of a magnesium-air battery and paired with an air cathode to form a magnesium-air battery. A seawater-type electrolyte containing chloride ions was used.

[0042] During battery discharge, the rare-earth hydride dispersion structure can remain stable within the magnesium matrix for a long period, causing the anode to exhibit uniform dissolution behavior during discharge, thereby improving the battery's operational stability at higher discharge current densities. Figure 3 As shown.

[0043] Example 4

[0044] The magnesium-based anode material prepared in Example 2 was paired with an AgCl cathode to construct a seawater-activated power supply system.

[0045] The power supply can be stored in a dry state before use. When the power supply comes into contact with seawater, the magnesium-based anode material undergoes an electrochemical reaction under the action of the electrolyte, thereby outputting electrical energy.

[0046] Because the magnesium-based anode has a rare-earth hydride dispersion structure inside, the power supply can maintain stable output characteristics even under high discharge load conditions, such as... Figure 4 As shown. Suitable for emergency power supply, marine equipment power supply, or other power supply scenarios requiring rapid activation.

[0047] Comparative Example

[0048] Similar to Example 1, except that the magnesium-based material containing rare earth elements was heat-treated under an inert atmosphere. The heat treatment conditions were as follows: after evacuation, high-purity argon gas with a purity of >99.999% was introduced at 0.2 MPa, and heat-treated at 200°C for 2 hours, then heat-treated at 400°C for half an hour. This process was repeated twice, and then heat-treated at 100°C under a 0.1 MPa argon atmosphere for 24 hours.

[0049] After the above treatment, the structure and performance of the obtained magnesium-based material were tested. The results showed that no rare earth hydride phase was formed in the material, and the rare earth elements still existed in the original solid solution state or intermetallic compound state. No structural features of dispersed distribution of rare earth hydrides were observed in the material.

[0050] The anode material obtained from the comparative example was processed into an anode component and used in an electrochemical energy conversion device for discharge testing under the same conditions. The results showed that during discharge, the anode was prone to uneven reaction, increased polarization, or unstable output under high current density conditions, and its overall discharge performance was significantly lower than that of the magnesium-based anode material treated with in-situ hydrogenation in Example 1.

[0051] The comparative results show that it is difficult to achieve the same technical effect as the present invention by simply using conventional heat treatment or inert atmosphere treatment without constructing a rare earth hydride dispersion structure in situ inside the material. This further proves the key role of in-situ hydrogenation construction of rare earth hydride dispersion structure in improving the performance of magnesium-based anodes.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A magnesium-based anode with an in-situ hydrogenation structure for constructing a rare-earth hydride dispersion, characterized in that, The magnesium-based anode comprises a magnesium matrix and a rare earth hydride phase distributed in the magnesium matrix; The rare earth hydride phase is formed by in-situ hydrogenation of a magnesium-based alloy containing rare earth elements. The rare earth hydride phase is dispersed in the interior or interface region of the magnesium matrix to form a rare earth hydride / magnesium composite structure.

2. The magnesium-based anode with an in-situ hydrogenation structure for constructing a rare-earth hydride dispersion as described in claim 1, characterized in that, The rare earth elements include one or more of cerium, lanthanum, praseodymium, neodymium, samarium, and yttrium.

3. The magnesium-based anode with an in-situ hydrogenation structure for constructing a rare-earth hydride dispersion according to claim 1 or 2, characterized in that, The magnesium-based alloy containing rare earth elements is a magnesium-rare earth binary alloy or a multi-element magnesium-based alloy containing other alloying elements.

4. The magnesium-based anode with an in-situ hydrogenation structure for constructing a rare-earth hydride dispersion as described in claim 3, characterized in that, The rare earth hydride phase is composed of nano- or submicron-sized particles, island structures, or continuous network structures.

5. The magnesium-based anode with an in-situ hydrogenation structure for constructing a rare-earth hydride dispersion according to claim 1 or 4, characterized in that, The dispersion mode is a discontinuous or semi-continuous dispersion distribution mode.

6. The method for preparing a magnesium-based anode with an in-situ hydrogenation structure of rare earth hydride dispersion as described in any one of claims 1 to 5, characterized in that, Includes the following steps: In-situ hydrogenation treatment of magnesium-based alloys containing rare earth elements allows for the selective hydrogenation of rare earth elements, forming rare earth hydride phases, thus yielding magnesium-based anodes.

7. The preparation method according to claim 6, characterized in that, The in-situ hydrogenation process is carried out in a hydrogen atmosphere or a hydrogen-containing environment.

8. The preparation method according to claim 7, characterized in that, The in-situ hydrogenation process is as follows: first, pre-activate in a hydrogen atmosphere at 150~250℃ for 1~3h; then raise the temperature to 350~450℃ and dehydrogenate under vacuum for 0.5~1.5h, repeat several times, and then cool down to 100~200℃ for hydrogenation for 12~36h.

9. The application of the magnesium-based anode with a rare earth hydride dispersion structure constructed according to any one of claims 1 to 5 in a metal-air battery.

10. The application according to claim 9, characterized in that, The metal-air battery is a magnesium-air battery, a magnesium-seawater battery, or a magnesium-silver halide battery.

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