CN114606418B - A kind of magnesium-air battery Mg-Bi-In-Y anode material and its preparation method and application - Google Patents

Abstract

The invention belongs to the field of chemical power supply electrode materials, and discloses a Mg-Bi-In-Y anode material of a magnesium air battery, and a preparation method and application thereof. The anode material is prepared from the following raw materials in percentage by mass: 0.1-0.4% of bismuth, 0.1-0.4% of indium, 0.5-2% of intermediate alloy Mg-20Y and the balance of high-purity metal magnesium. The preparation method comprises the following steps: weighing raw materials and carrying out pretreatment; placing the pretreated high-purity magnesium in a graphite crucible, placing the graphite crucible in a well type furnace under the protection of a covering agent, heating at 710-730 ℃, sequentially adding the pretreated bismuth, indium and an intermediate alloy Mg-20Y after the high-purity magnesium is molten, stirring for 1-3 min, and then preserving heat for 10min to obtain a melt; and standing the melt In a well type furnace for 5min, and casting the melt In a preheated iron mold under the protection of sulfur powder to obtain the Mg-Bi-In-Y anode material of the magnesium air battery.

Description

A kind of magnesium-air battery Mg-Bi-In-Y anode material and its preparation method and application

technical field

The invention belongs to the field of chemical power supply electrode materials, and in particular relates to a Mg-Bi-In-Y anode material for a magnesium-air battery and a preparation method and application thereof.

Background technique

Magnesium has a relatively negative standard electrode potential, a large theoretical specific capacity, and a small density. Based on the above advantages, magnesium is widely used in various chemical power sources as an ideal anode material. At the same time, the reserves of magnesium in the earth's crust are very rich, and the price is relatively low. In addition, most of the magnesium alloys are non-toxic and environmentally friendly. It can be seen that magnesium alloys have great application potential as battery anode materials, and it is of great significance to study the electrochemical properties of magnesium alloys as battery anode (negative) materials.

Magnesium-air batteries have the advantages of low cost, high energy conversion rate, abundant resources and no pollution, and have great development and application prospects. However, magnesium anodes face problems such as difficult peeling of corrosion products, severe hydrogen evolution self-corrosion reaction, metal particle shedding, and low anode utilization during application, which limit the further development of magnesium-air batteries. In addition, magnesium-air batteries need to prolong the storage time when they are not discharged, which puts forward higher requirements for the corrosion resistance of magnesium anodes at open circuit potential. Therefore, finding high-performance magnesium alloy anode materials is one of the hotspots and difficulties in magnesium-air battery research. conflicting.

At present, adding other alloying elements to magnesium is a conventional method to effectively improve the anode utilization rate of magnesium alloys. Add one or more elements such as aluminum, zinc, tin, indium, bismuth, lead, gallium, manganese to magnesium to form binary, ternary or even multi-element magnesium alloy anode materials, so as to improve magnesium alloy anode materials The discharge activity of magnesium anode can be improved, which can promote corrosion homogenization and grain refinement, and improve the corrosion electrochemical performance of magnesium anode. At present, magnesium alloy anodes mainly exist in the following systems: Mg-Al-Zn-(RE), Mg-Al-Pb, Mg-Ca, Mg-Li, Mg-Hg-X, etc.

However, there are few reports on the microalloying of high-purity magnesium with more than two elements. Taking high-purity magnesium as the research object, the composite addition of activating elements bismuth and indium, and the microalloying of rare earth element yttrium are used to solve the contradiction between passivation and activation Not yet reported in the literature. In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a Mg-Bi-In-Y anode material for a magnesium-air battery. This method takes high-purity magnesium as the research object. Through the micro-alloying of bismuth, indium, yttrium and other elements, the corrosion resistance of magnesium anode at open circuit potential is enhanced, and the corrosion products peeling off during the discharge process are promoted, and hydrogen evolution and metal particles are inhibited. Improve anode utilization, thereby improving overall anode performance.

Another object of the present invention is to provide a Mg-Bi-In-Y anode material for a magnesium-air battery prepared by the above preparation method.

Another object of the present invention is to provide an application of the above-mentioned Mg-Bi-In-Y anode material for magnesium-air batteries.

The object of the present invention is achieved through the following technical solutions:

A Mg-Bi-In-Y anode material for a magnesium-air battery, the anode material is prepared from the following raw materials by mass percentage: bismuth 0.1-0.4%, indium 0.1-0.4%, and intermediate alloy Mg-20Y 0.5- 2%, and the balance is high-purity metal magnesium.

The above-mentioned preparation method of a magnesium-air battery Mg-Bi-In-Y anode material, comprising the following steps:

(1) in a dry environment, take by weighing high-purity metal magnesium, bismuth, indium and master alloy Mg-20Y according to the mass percentage of the above-mentioned raw materials, and carry out pretreatment of each raw material respectively;

(2) Place the pretreated high-purity metal magnesium in a graphite crucible, put it into a pit-type resistance furnace under the protection of a covering agent, and heat it at 710-730 ° C. After the high-purity metal magnesium is melted, add it in turn. The pretreated bismuth, indium, and intermediate alloy Mg-20Y are stirred with a high-purity graphite rod for 1-3 minutes and then kept for 10 minutes to obtain a melt;

(3) After standing the melt in a pit-type resistance furnace for 5 minutes, it is cast in a preheated iron mold under the protection of sulfur powder to obtain a Mg-Bi-In-Y anode material for a magnesium-air battery.

The pretreatment in step (1) refers to cleaning and removing oxide scale, and baking in an oven at 100-200° C. for 1-2 hours.

The covering agent of step (2) is a mixture of magnesium chloride, potassium chloride, calcium fluoride and sodium chloride.

In the step (2), the preheated iron mold is subjected to rust removal treatment and zinc oxide coating on its inner wall before use, and is preheated in an oven at 100-200° C. for 1-2 hours.

The covering agent in step (2) and the sulfur powder in step (3) were both dried in a vacuum drying oven at 60° C. for 12 hours before use.

The size of the Mg-Bi-In-Y anode material for the magnesium-air battery obtained by casting in the step (3) is 200 mm×200 mm×(15-20) mm.

A Mg-Bi-In-Y anode material for a magnesium-air battery prepared by the above-mentioned preparation method.

Application of the above-mentioned magnesium-air battery Mg-Bi-In-Y anode material in the preparation of magnesium-air battery.

Compared with the prior art, the present invention has the following advantages and effects:

The invention prepares Mg-Bi-In-Y anode ingot by smelting and casting method, takes high-purity magnesium as the matrix, adopts the compound addition of activating elements bismuth and indium and rare earth element yttrium, realizes the micro-alloying of high-purity magnesium, and solves the problem of activation of magnesium anode material. In contradiction to passivation, the dissolution uniformity and corrosion resistance of magnesium anodes are increased. The results show that the coexistence of the three alloy elements can reduce the corrosion current density and increase the discharge voltage, and at the same time suppress the discharge hydrogen evolution, so that the Mg-Bi-In-Y has a higher anode utilization rate. good usability.

Description of drawings

Fig. 1 is the polarization curve diagram of high-purity magnesium and the magnesium anode material of Example 1 and Comparative Examples 1-3;

Fig. 2 is the voltage-time curve of high-purity magnesium and magnesium anode materials of Example 1 and Comparative Examples 1-3 assembled into a magnesium-air battery at 10 mA cm ^-2 in a 3.5% NaCl solution;

Fig. 3 is the discharge hydrogen evolution of high-purity magnesium and Example 1 and the magnesium anode material of Comparative Examples 1-3 at 10mA cm ^-2 ;

FIG. 4 shows the anode utilization rate of high-purity magnesium and the magnesium anode materials of Example 1 and Comparative Examples 1-3 at 10 mA cm ⁻² .

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

The experimental methods involved in this example, if the specific conditions are not indicated, are processed according to the conventional conditions in the art; the raw materials, reagents, etc. used, if there is no special description, are regarded as the raw materials and reagents obtained from the conventional market. . Any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention fall within the scope of protection claimed by the present invention.

Example 1

This embodiment provides a Mg-0.1Bi-0.1In-0.1Y anode material, and its preparation method is as follows:

1. The Mg-0.1Bi-0.1In-0.1Y anode material of this embodiment is composed of elements in the following mass fractions: bismuth 0.1%, indium 0.1%, yttrium 0.1%, magnesium 99.97%. The raw materials used are high-purity magnesium, high-purity bismuth, high-purity indium and magnesium-yttrium master alloy (Mg-20Y).

2. Weigh high-purity magnesium, bismuth, indium and Mg-20Y, and wash these raw materials to remove surface dirt and oxide scale. All raw materials must be baked in an oven at a temperature of 100-200 ℃ before smelting 1 -2 hours to remove the contained moisture.

3. The inner wall of the iron mold used for smelting and casting must be cleaned (mainly rust removal) and coated with zinc oxide before smelting. Preheat for 1 to 2 hours. Crucibles used for smelting must be cleaned of slag and checked for integrity before use.

4. The covering agent and sulfur powder added in the smelting process must be dried in a vacuum drying oven at 60°C for 12 hours.

5. Put the pretreated high-purity magnesium into the graphite crucible, in the covering agent (the covering agent is composed of the following components by mass fraction: MgCl ₂ 45%, KCl 35%, CaF ₂ 10%, NaCl 10% ) placed in a pit furnace under the protection of Stir for 2 to 3 minutes to make the composition uniform, and keep the temperature for 10 minutes.

6. After the well-stirred melt is allowed to stand for 5 minutes in a pit furnace, it is cast into a flat iron mold under the protection of sulfur powder to obtain Mg-0.1Bi with a size of 200mm×200mm×(15～20)mm -0.1In-0.1Y anode ingot. The middle area of the ingot is selected as the test sample, denoted as Mg-Bi-In-Y.

Example 2

This embodiment provides an Mg-0.4Bi-0.4In-0.4Y anode material, the preparation method of which is basically the same as that of Embodiment 1, except that the anode material is composed of the following elements in mass fractions: bismuth 0.4%, indium 0.4%, Yttrium 0.4%, Magnesium 98.8%. The raw materials used are high-purity magnesium, high-purity bismuth, high-purity indium and magnesium-yttrium master alloy.

Example 3

This embodiment provides a Mg-0.1Bi-0.1In-0.1Y anode material, the preparation method of which is basically the same as that of Embodiment 1, the only difference is that the smelting temperature of the pit furnace is 710°C.

Example 4

This embodiment provides a Mg-0.1Bi-0.1In-0.1Y anode material, the preparation method of which is basically the same as that of Embodiment 1, the only difference is that the smelting temperature of the pit furnace is 720°C.

Comparative Example 1

This comparative example provides a Mg-Bi anode material, the preparation method of which is similar to that of Example 1, the difference is that only high-purity magnesium and Bi are used as raw materials, and the mass fractions are 99.9% and 0.1%, respectively, to obtain a Mg-0.1%Bi anode For ingot casting, the middle area of the ingot is selected as a comparative test sample, denoted as Mg-Bi.

Comparative Example 2

This comparative example provides a Mg-In anode material, the preparation method of which is similar to that of Example 1, the difference is that only high-purity magnesium and In are used as raw materials, and the mass fractions are 99.9% and 0.1%, respectively, to obtain Mg-0.1%In For anode ingot casting, the middle area of the ingot is selected as a comparative test sample, denoted as Mg-In.

Comparative Example 3

This comparative example provides a Mg-Bi-In anode material, the preparation method of which is similar to that of Example 1, the difference is that only high-purity magnesium, Bi and In are used as raw materials, and the mass fractions are 99.8%, 0.1% and 0.1%, respectively. A Mg-0.1%Bi-0.1%In anode ingot was obtained, and the middle area of the ingot was selected as a comparative test sample, denoted as Mg-Bi-In.

Performance testing and analysis

As shown in Figure 1, compared with high-purity magnesium and the corresponding Comparative Examples 1-3, after adding Y element, the corrosion current density of the magnesium anode material (Mg-Bi-In-Y) in Example 1 is significantly reduced, indicating that Y The addition of elements can improve the compactness and corrosion resistance of the magnesium alloy surface film.

As shown in Figure 2, under the current density of 10 mA cm ^-2 , the discharge platforms of the magnesium anode materials of Example 1 and Comparative Examples 1-3 are higher than those of pure magnesium, and the magnesium anode material of Example 1 (Mg-Bi- In-Y) has the highest discharge voltage, indicating that the magnesium anode material of the present invention has higher discharge activity during the re-discharge process.

As shown in Figure 3, the hydrogen evolution behavior of galvanostatic discharge for 3h under the current density of 10mA cm ^-2 shows that the hydrogen evolution behavior of Comparative Examples 1-3 is relatively similar, and all are lower than pure magnesium, with Example 1 magnesium anode material ( The hydrogen evolution rate of Mg-Bi-In-Y) is the lowest, which is lower than that of high-purity magnesium and comparative examples 1-3, indicating that the alloy material of the present invention has good performance of inhibiting the side reaction of hydrogen evolution.

As shown in Figure 4, the magnesium anode material (Mg-Bi-In-Y) of Example 1 maintained a relatively high anode utilization rate (61.5%).

From the above, it can be seen that the present invention prepares a Mg-Bi-In-Y anode material by combining several alloy elements in appropriate proportions. During the discharge process of the magnesium-air battery, the anode material can provide higher voltage and The anode utilization rate is excellent, and the comprehensive electrochemical performance is excellent.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (8)

1. a magnesium-air battery Mg-Bi-In-Y anode material, is characterized in that: this anode material is prepared from the following raw materials by mass percentage: bismuth 0.1～0.4%, indium 0.1～0.4%, middle Alloy Mg-20Y 0.5~2%, the balance is high-purity metal magnesium; The magnesium-air battery Mg-Bi-In-Y anode material is prepared according to the following preparation method: (1) In a dry environment, weigh high-purity metal magnesium, bismuth, indium and master alloy Mg-20Y according to the mass percentage of the raw materials, and preprocess the raw materials respectively; (2) Place the pretreated high-purity metal magnesium in a graphite crucible, put it into a pit-type resistance furnace under the protection of a covering agent, and heat it at 710~730 ° C. After the high-purity metal magnesium is melted, add it in turn. The pretreated bismuth, indium and master alloy Mg-20Y are stirred with a high-purity graphite rod for 1-3 minutes and then kept for 10 minutes to obtain a melt; (3) After the melt was allowed to stand in a pit-type resistance furnace for 5 minutes, it was cast in a preheated iron mold under the protection of sulfur powder to obtain a Mg-Bi-In-Y anode material for a magnesium-air battery. 2. The Mg-Bi-In-Y anode material for a magnesium-air battery according to claim 1, characterized in that: the pretreatment in step (1) refers to cleaning and removing oxide scale, and placing it in an oven at 100 Bake at ~200℃ for 1~2 hours. 3. The Mg-Bi-In-Y anode material for a magnesium-air battery according to claim 1, wherein the covering agent in step (2) is magnesium chloride, potassium chloride, calcium fluoride and sodium chloride mixture. 4 . The Mg-Bi-In-Y anode material for a magnesium-air battery according to claim 1 , wherein the preheated iron mold in step (3) is derusted on its inner wall before use. 5 . Treated and coated with zinc oxide, preheated in an oven at 100~200°C for 1~2 hours. 5. The Mg-Bi-In-Y anode material for a magnesium-air battery according to claim 1, wherein the covering agent in step (2) and the sulfur powder in step (3) are both in Dry in a vacuum oven at 60 °C for 12 h. 6. The Mg-Bi-In-Y anode material for a magnesium-air battery according to claim 1, characterized in that: the size of the Mg-Bi-In-Y anode material for the magnesium-air battery obtained by casting in step (3) It is 200 mm×200 mm×(15~20) mm. 7. the preparation method of a kind of magnesium-air battery Mg-Bi-In-Y anode material according to claim 1, is characterized in that according to the following operation steps: (1) In a dry environment, weigh high-purity metal magnesium, bismuth, indium and master alloy Mg-20Y according to the mass percentage of the raw materials described in claim 1, and preprocess the raw materials respectively; (2) Place the pretreated high-purity metal magnesium in a graphite crucible, put it into a pit-type resistance furnace under the protection of a covering agent, and heat it at 710~730 ° C. After the high-purity metal magnesium is melted, add it in turn. The pretreated bismuth, indium and master alloy Mg-20Y are stirred with a high-purity graphite rod for 1-3 minutes and then kept for 10 minutes to obtain a melt; (3) After the melt was allowed to stand in a pit-type resistance furnace for 5 minutes, it was cast in a preheated iron mold under the protection of sulfur powder to obtain a Mg-Bi-In-Y anode material for a magnesium-air battery. 8. The application of the Mg-Bi-In-Y anode material for magnesium-air batteries according to claim 1 in the preparation of magnesium-air batteries.

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