Anode alloy material for magnesium air battery, preparation method thereof and battery
Technical Field
The invention relates to the technical field of materials, in particular to an anode alloy material for a magnesium air battery, a preparation method of the anode alloy material and the battery.
Background
The magnesium air battery is a metal fuel battery, which is composed of an anode, a cathode, electrolyte and the like. The magnesium air battery has the advantages of rich resources, high reaction activity, light weight, no pollution of reaction products, low price, wide working temperature range, high safety, high theoretical energy density and the like. The earliest applications of magnesium air batteries dates back to the 60's of the 20 th century when the U.S. general electric company developed a neutral electrolyte magnesium air battery. Currently, the magnesium air battery can be used as an emergency power supply for hospitals, schools and other places, and in the fields of military affairs, communication and the like, and can also be used as an underwater power supply for lighthouses, buoys, underwater real equipment and the like.
The performance of magnesium alloy anodes is critical in determining the performance of magnesium air cells. Magnesium is an ideal anode material for chemical power sources. Magnesium has a lower density, a more negative standard electrode potential, a large theoretical specific capacity. However, magnesium alloys have many problems as anodes for magnesium air batteries, and first, magnesium has strong hydrogen self-corrosion, and generates a large amount of hydrogen gas during discharge, thereby lowering the faraday efficiency of the anode. Secondly, the magnesium anode generates compact Mg (OH) on the surface during the self-corrosion process2The passive film hinders the dissolution of the magnesium anode, thereby reducing the discharge performance of the battery; in addition, magnesium has a negative differential effect during corrosion, which results in a magnesium anode having a low anode efficiency during discharge. Thus, a suitable magnesium anode should have a low hydrogen evolution self-corrosion rate, a small negative differential effect, and easily shed corrosion products.
Around reducing the hydrogen evolution reaction of the magnesium air battery anode and improving the discharge activity of the magnesium anode, researchers at home and abroad develop binary, ternary or even multi-element magnesium alloy anode materials, and a main alloy system comprises: Mg-Al-Zn, Mg-Al-Mn, Mg-Al-Pb, Mg-Al-Sn, Mg-Ca, Mg-Li, etc. Aiming at the existing alloy material, the magnesium alloy anode material with more negative discharge potential and higher anode utilization rate can be further researched.
In view of this, the invention is particularly proposed.
Disclosure of Invention
The invention aims to provide an anode alloy material for a magnesium air battery, a preparation method thereof and the battery.
The invention is realized by the following steps:
in a first aspect, an embodiment of the present invention provides an anode alloy material for a magnesium air battery, which includes, by mass: 1.5 to 11.5% of Al, 0.5 to 6.5% of Ca, 0.2 to 6.0% of Bi, 0.1 to 4.0% of Ce, and the balance of Mg and inevitable impurities.
In a second aspect, an embodiment of the present invention provides a preparation method of the anode alloy material for a magnesium air battery, including: and carrying out solution treatment, rolling and annealing on the casting blank, wherein the content of each element component in the casting blank is matched with the content of the element component of the anode alloy material to be prepared.
In an alternative embodiment, the solution treatment is a two-stage solution treatment, the two-stage solution treatment comprising:
low-temperature solid solution: keeping the temperature of the casting blank at 300-380 ℃ for 2-8 h;
high-temperature solid solution: and (3) placing the product obtained by low-temperature solid solution at 400-500 ℃ and keeping the temperature for 8-15 h.
In an alternative embodiment, the slab is obtained after the solution treatment, and the removing of the oxide layer on the surface of the slab is further included before the rolling.
In an optional embodiment, the rolling is performed by controlling the temperature of the roller to be 100-320 ℃ for multiple times of rolling, and except for the last time of rolling, intermediate annealing is performed after each time of rolling;
in an optional embodiment, after the solution treatment, the plate blank is heated to 120-380 ℃, and then is rolled after heat preservation for 20-80 min.
In an optional embodiment, the intermediate annealing temperature is 100-300 ℃, and the annealing time is 10-60 min.
In an optional embodiment, the deformation amount of each pass during rolling is controlled within 10-35%.
In an optional embodiment, the annealing temperature after the rolling to the target thickness is 120-380 ℃, and the annealing time is 30-180 min.
In an alternative embodiment, the solution treatment further comprises: and after melting the pure magnesium ingot, adding pure aluminum, pure bismuth, pure calcium, Mg-Ca alloy and Mg-Ce alloy into the molten pure magnesium ingot, refining, standing and pouring to obtain a casting blank.
In a second aspect, embodiments of the present invention provide a battery, which includes an anode made of the anode alloy material provided in the embodiments of the present invention or an anode made of the anode alloy material provided in the embodiments of the present invention.
The invention has the following beneficial effects:
the anode alloy material for the magnesium air battery is added with Al with proper content, so that the corrosion resistance of the magnesium alloy can be effectively improved; the addition of Ca with proper content can improve the discharge voltage, specific capacity and anode efficiency of the magnesium alloy anode, so that the open-circuit potential of the magnesium alloy anode is more negative; the addition of Bi with proper content can effectively improve the hydrogen evolution overpotential of the magnesium alloy anode; the addition of Ce with proper content can make the grain structure of the magnesium alloy finer and more uniform, thereby effectively improving the utilization rate of the anode. The elements have synergistic effect in multiple aspects, can form various precipitated phases, make the structure fine and uniform, improve the hydrogen evolution overpotential of the magnesium anode, effectively inhibit the hydrogen evolution reaction, make the discharge potential of the alloy material more negative, and make the anode utilization rate higher.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The anode alloy material for the magnesium air battery, the preparation method thereof and the battery provided by the invention are specifically explained below.
The embodiment of the invention provides an anode alloy material for a magnesium air battery, which comprises the following components in percentage by mass: 1.5 to 11.5% of Al, 0.5 to 6.5% of Ca, 0.2 to 6.0% of Bi, 0.1 to 4.0% of Ce, and the balance of Mg and inevitable impurities.
Al with proper content is added into the anode alloy material, so that the corrosion resistance of the magnesium alloy can be effectively improved; the addition of Ca with proper content can improve the discharge voltage, specific capacity and anode efficiency of the magnesium alloy anode, so that the open-circuit potential of the magnesium alloy anode is more negative; the addition of Bi with proper content can effectively improve the hydrogen evolution overpotential of the magnesium alloy anode; the addition of Ce with proper content can make the grain structure of the magnesium alloy finer and more uniform, thereby effectively improving the utilization rate of the anode. The elements have synergistic effect in multiple aspects, can form various precipitated phases, make the structure fine and uniform, improve the hydrogen evolution overpotential of the magnesium anode, effectively inhibit the hydrogen evolution reaction, make the discharge potential of the alloy material more negative, and make the anode utilization rate higher.
The content of inevitable impurities is negligible, and the inevitable impurities mainly comprise iron, copper and nickel, and the inevitable impurities comprise the following components in percentage by mass in the alloy: fe is less than or equal to 0.01 percent, Cu is less than or equal to 0.01 percent, and Ni is less than or equal to 0.01 percent.
The preparation method of the anode alloy material for the magnesium air battery comprises the following steps:
and carrying out solution treatment, rolling and annealing on a casting blank, wherein the content of each element component in the casting blank is matched with the content of the element component of the anode alloy material to be prepared.
The method specifically comprises the following steps:
s1, preparing casting blank
Preparing materials according to the content requirements of each element component in the anode alloy material. And then melting the pure magnesium ingot, adding pure aluminum, pure bismuth, pure calcium, Mg-Ca alloy and Mg-Ce alloy, melting, refining, stirring, deslagging, standing and pouring to obtain a casting blank.
Preferably, the Mg-Ca alloy and the Mg-Ce alloy are respectively Mg-20Ca intermediate alloy and Mg-25Ce intermediate alloy.
S2 solution treatment
And carrying out solid solution treatment on the casting blank by adopting a two-stage solid solution treatment mode to obtain a slab.
The two-stage solution treatment comprises the following steps:
low-temperature solid solution: keeping the temperature of the casting blank at 300-380 ℃ for 2-8 h;
high-temperature solid solution: and (3) placing the product obtained by low-temperature solid solution at 400-500 ℃ and keeping the temperature for 8-15 h.
According to the method, the casting blank is subjected to double-stage solution treatment, so that the structure of the magnesium alloy anode material can be effectively refined, the hydrogen evolution overpotential of the magnesium anode is further improved, and the hydrogen evolution reaction is effectively inhibited, so that the anode alloy material for the magnesium air battery with more negative discharge potential and higher anode utilization rate is obtained.
S3 rolling
Heating the plate blank to 120-380 ℃, preserving heat for 20-80 min, and then rolling. The heat preservation is carried out for a proper time at the temperature, and then the rolling is carried out, so that the grain size of the magnesium alloy anode can be refined, and the uniformity of the structure is improved.
In order to ensure that the alloy material with more uniform as-cast structure is prepared, the method is carried out by adopting a multi-pass rolling mode.
The temperature of the roller is controlled to be 100-320 ℃ during rolling, and the deformation of each pass is controlled to be 10-35%. Except for the last pass, intermediate annealing is carried out after each pass of rolling. Preferably, the intermediate annealing temperature is 100-300 ℃, and the annealing time is 10-60 min.
The rolling times are selected to be appropriate according to the target thickness of the anode alloy material plate to be obtained. And stopping rolling after the last rolling to the required target thickness.
S4 annealing
And (4) annealing after the last rolling is finished, wherein the annealing temperature is 120-380 ℃, and the annealing time is 30-180 min.
The embodiment of the invention also provides a battery, which comprises an anode made of the anode alloy material provided by the embodiment of the invention or an anode made of the anode alloy material prepared by the preparation method provided by the embodiment of the invention. Therefore, the battery has good performance.
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
Preparing materials: the alloy comprises the following elements in percentage by mass:
7.5 percent of Al, 5.6 percent of Ca, 3.4 percent of Bi, 3.5 percent of Ce, and the limiting elements of less than or equal to 0.01 percent of Fe, less than or equal to 0.01 percent of Cu, less than or equal to 0.01 percent of Ni, and the balance of Mg.
Firstly, heating and melting a pure magnesium ingot with the magnesium content of 99.99%, heating to 680-760 ℃ under the protection of a flux for smelting, sequentially adding pure aluminum, pure bismuth and intermediate alloys of Mg-20Ca and Mg-25Ce according to the component proportion, and obtaining a magnesium alloy anode material casting blank for the air battery through refining, stirring, deslagging, standing and pouring.
Then, carrying out two-stage solution treatment on the casting blank, wherein the low-temperature solution temperature is 350 ℃, and the heat preservation time is 4 h; the high-temperature solid solution temperature is 480 ℃, and the heat preservation time is 9 hours; and (4) carrying out warm rolling on the slab subjected to the double-stage solution treatment after removing the surface oxide layer. Heating the plate blank to 280 ℃, preserving heat for 40min, then starting warm rolling, controlling the temperature of a roller at 180 ℃, and controlling the deformation of rolling passes at 20%. And (3) performing intermediate annealing once after each rolling pass, wherein the intermediate annealing temperature is 200 ℃, and the annealing time is 20 min. And finally, annealing the magnesium alloy anode material at 260 ℃ for 40 min.
Example 2
Preparing materials: the alloy comprises the following elements in percentage by mass:
1.5 percent of Al, 6.5 percent of Ca, 0.2 percent of Bi and 4.0 percent of Ce, less than or equal to 0.01 percent of limiting element Fe, less than or equal to 0.01 percent of Cu, less than or equal to 0.01 percent of Ni and the balance of Mg.
Firstly, heating and melting a pure magnesium ingot with the magnesium content of 99.99%, heating to 680 ℃ under the protection of a flux for smelting, sequentially adding pure aluminum, pure bismuth and intermediate alloys of Mg-20Ca and Mg-25Ce according to the component proportion, and obtaining a magnesium alloy anode material casting blank for the air battery through refining, stirring, deslagging, standing and pouring.
Then, carrying out two-stage solution treatment on the casting blank, wherein the low-temperature solution temperature is 300 ℃, and the heat preservation time is 2 h; the high-temperature solid solution temperature is 400 ℃, and the heat preservation time is 8 hours; and (4) carrying out warm rolling on the slab subjected to the double-stage solution treatment after removing the surface oxide layer. Heating the plate blank to 120 ℃, preserving heat for 80min, then starting warm rolling, controlling the temperature of a roller at 100 ℃, and controlling the deformation of rolling passes at 35%. And (3) performing intermediate annealing once after each rolling pass, wherein the intermediate annealing temperature is 100 ℃, and the annealing time is 10 min. And finally, annealing the magnesium alloy anode material at 120 ℃ for 30 min.
Example 3
Preparing materials: the alloy comprises the following elements in percentage by mass:
preparing 11.5 percent of Al, 0.5 percent of Ca, 6.0 percent of Bi and 0.1 percent of Ce, limiting elements of less than or equal to 0.01 percent of Fe, less than or equal to 0.01 percent of Cu, less than or equal to 0.01 percent of Ni and the balance of Mg.
Firstly, heating and melting a pure magnesium ingot with the magnesium content of 99.99%, heating to 680 ℃ under the protection of a flux for smelting, sequentially adding pure aluminum, pure bismuth and intermediate alloys of Mg-20Ca and Mg-25Ce according to the component proportion, and obtaining a magnesium alloy anode material casting blank for the air battery through refining, stirring, deslagging, standing and pouring.
Then, carrying out two-stage solution treatment on the casting blank, wherein the low-temperature solution temperature is 380 ℃, and the heat preservation time is 8 h; the high-temperature solid solution temperature is 500 ℃, and the heat preservation time is 15 h; and (4) carrying out warm rolling on the slab subjected to the double-stage solution treatment after removing the surface oxide layer. Heating the plate blank to 380 ℃, preserving heat for 20min, then starting warm rolling, controlling the temperature of a roller at 320 ℃, and controlling the deformation of rolling passes at 10%. And (3) performing intermediate annealing once after each rolling pass, wherein the intermediate annealing temperature is 300 ℃, and the annealing time is 60 min. And finally, annealing the magnesium alloy anode material at 380 ℃ for 180 min.
Example 4
This embodiment is substantially the same as embodiment 1 except that:
the alloy comprises the following elements in percentage by mass:
4.0 percent of Al, 4.2 percent of Ca, 1.7 percent of Bi, 2.9 percent of Ce, less than or equal to 0.01 percent of limiting element Fe, less than or equal to 0.01 percent of Cu, less than or equal to 0.01 percent of Ni and the balance of Mg.
Example 5
This embodiment is substantially the same as embodiment 1 except that:
the alloy comprises the following elements in percentage by mass:
8.3 percent of Al, 2.1 percent of Ca, 4.8 percent of Bi, 1.6 percent of Ce, less than or equal to 0.01 percent of limiting element Fe, less than or equal to 0.01 percent of Cu, less than or equal to 0.01 percent of Ni and the balance of Mg.
Example 6
This example is substantially the same as example 1 except that the solution treatment was carried out in a single stage at 440 ℃ for 14 hours.
Comparative example 1
This comparative example provides a commercial magnesium alloy AZ61 alloy anode material.
Comparative example 2
This comparative example is essentially the same as example 1, except that: ca in the alloy components is replaced by Mg with the same quantity.
Comparative example 3
This comparative example is essentially the same as example 1, except that: al in the alloy components is replaced by Mg with the same quantity.
Comparative example 4
This comparative example is essentially the same as example 1, except that: bi in the alloy components is replaced by Mg with the same quantity.
Comparative example 5
This comparative example is essentially the same as example 1, except that: the Ce in the alloy components is replaced by the same amount of Mg.
Examples of the experiments
The electrochemical properties of the magnesium alloy anode materials of examples 1 to 6 and comparative examples 1 to 5 were measured by constant current discharge at a current density of 50mA/cm2Under the condition of the reaction. Data are recorded in table 1.
TABLE 1 electrochemical Properties of magnesium alloy anode materials of each group
As can be seen from table 1, the average discharge potential of the magnesium alloy anode material provided in the embodiments of the present invention is more negative than that of the conventional AZ61 magnesium alloy anode material, and the anode utilization rate is higher. Comparing example 6 with example 1, it is found that the average discharge potential of example 1 is more negative than that of example 6, the anode utilization rate is higher, and the two-stage solution treatment can further refine the structure of the magnesium alloy anode material, further improve the hydrogen evolution overpotential of the magnesium anode and inhibit the hydrogen evolution reaction compared with the conventional one-stage solution treatment. Comparing example 1 with comparative examples 2-5, it is found that each electrochemical performance of example 1 is better than that of comparative examples 2-5, which indicates that any one of Al, Ca, Bi and Ce in the element composition is not indispensable.
In conclusion, the anode alloy material for the magnesium air battery provided by the invention has the advantages that the corrosion resistance of the magnesium alloy can be effectively improved by adding Al with proper content; the addition of Ca with proper content can improve the discharge voltage, specific capacity and anode efficiency of the magnesium alloy anode, so that the open-circuit potential of the magnesium alloy anode is more negative; the addition of Bi with proper content can effectively improve the hydrogen evolution overpotential of the magnesium alloy anode; the addition of Ce with proper content can make the grain structure of the magnesium alloy finer and more uniform, thereby effectively improving the utilization rate of the anode. The elements have synergistic effect in multiple aspects, can form various precipitated phases, make the structure fine and uniform, improve the hydrogen evolution overpotential of the magnesium anode, effectively inhibit the hydrogen evolution reaction, make the discharge potential of the alloy material more negative, and make the anode utilization rate higher.
The preparation method of the anode alloy material for the magnesium air battery can prepare the anode alloy material for the magnesium air battery with negative potential and high anode utilization rate.
Furthermore, the two-stage solution treatment is adopted during preparation, so that the structure of the magnesium alloy anode material can be refined, the hydrogen evolution overpotential of the magnesium anode is further improved, and the hydrogen evolution reaction is inhibited, so that the alloy material with more negative discharge potential and higher anode utilization rate is prepared.
The battery provided by the invention has good performance because the battery comprises the anode made of the anode alloy material for the magnesium air battery.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.