阅读说明：本技术 一种碱性铝-空气电池用含钙铝合金阳极材料及制备方法 (Calcium-containing aluminum alloy anode material for alkaline aluminum-air battery and preparation method thereof ) 是由 吴子彬 张海涛 邹晶 秦克 版春燕 崔建忠 于 2020-05-11 设计创作，主要内容包括：本发明提供一种碱性铝-空气电池用含钙铝合金阳极材料及制备方法,按质量百分比,所述含钙铝合金阳极材料由下述成分组成：Ca：0.01～1.0％,Sn：0～1.0％,Bi：0～1.0％,杂质含量≤0.30％,余量为Al；所述含钙铝合金阳极材料经熔炼、除气、扒渣、浇注、均匀化退火、轧制,固溶后制得。本发明所述阳极材料采用工业纯铝为原料,不含贵重的In、Ga等元素,不含对环境有害的Pb、Hg等元素,含有可以细化晶粒,改善阳极电化学性能的钙,降低了生产成本的同时,保持了阳极活性；合金元素Sn具有较高的氢过电位,可抑制析氢腐蚀,增加合金有效利用率,合金元素Bi可以降低铝合金表面的钝化性能并且提高阳极利用率,Bi还可以减少阳极微观结构的不均匀性,提高电流效率。(The invention provides a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery and a preparation method thereof, wherein the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.0%, Sn: 0 to 1.0%, Bi: 0-1.0%, impurity content less than or equal to 0.30%, and the balance of Al; the calcium-containing aluminum alloy anode material is prepared by smelting, degassing, slagging off, casting, homogenizing annealing, rolling and solid dissolving. The anode material adopts industrial pure aluminum as a raw material, does not contain valuable elements such as In and Ga, does not contain elements such as Pb and Hg which are harmful to the environment, and contains calcium which can refine crystal grains and improve the electrochemical performance of the anode, thereby reducing the production cost and simultaneously keeping the activity of the anode; the alloy element Sn has higher hydrogen overpotential, can inhibit hydrogen evolution corrosion, increases the effective utilization rate of the alloy, can reduce the passivation performance of the surface of the aluminum alloy and improve the utilization rate of the anode, and can reduce the nonuniformity of the microstructure of the anode and improve the current efficiency.)

1. A calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery is characterized in that: the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0 to 1.00%, Bi: 0-1.00%, less than or equal to 0.30% of impurity content, and the balance of Al.

2. The calcium-containing aluminum alloy anode material for alkaline aluminum-air batteries according to claim 1, wherein: the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

3. The calcium-containing aluminum alloy anode material for alkaline aluminum-air batteries according to claim 1, wherein: the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Bi: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

4. The calcium-containing aluminum alloy anode material for alkaline aluminum-air batteries according to claim 1, wherein: the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0.01 to 1.00%, Bi: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

5. The calcium-containing aluminum alloy anode material for alkaline aluminum-air batteries according to claim 1, wherein: the open-circuit voltage of the calcium-containing aluminum alloy anode material is 1.87-1.99V (Vs.SHE) and is 40 mA-cm^-2The discharge efficiency reaches 91.2-98.9% at the current density of (2), and the energy density is 3587.4-4037.7 Wh.kg^-1。

6. A method for preparing the calcium-containing aluminum alloy anode material for alkaline aluminum-air batteries according to claim 1, characterized in that: the calcium-containing aluminum alloy anode material is prepared by smelting, degassing, slagging off, casting, homogenizing annealing, rolling and solid solution, wherein the smelting process comprises the following steps: the method comprises the steps of proportioning according to alloy components, adding industrial pure aluminum into a medium-frequency smelting furnace, heating to 760-790 ℃ for melting, controlling the temperature to 720-750 ℃, adding an aluminum-calcium intermediate alloy into a melt, carrying out electromagnetic stirring on the melt for 5-30 min when the aluminum-calcium intermediate alloy is completely melted, controlling the temperature to 670-720 ℃ after the electromagnetic stirring if the alloy components contain low-melting-point alloy elements, adding the low-melting-point alloy elements, carrying out electromagnetic stirring on the melt for 5-15 min after the low-melting-point alloy elements are melted, wherein the low-melting-point alloy elements are Sn and/or Bi.

7. The method for preparing a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery according to claim 6, wherein: the degassing and slagging-off process comprises the following steps: introducing the melt obtained after smelting into a standing furnace at 730-750 ℃, introducing mixed gas into the standing furnace for 5-10 min, introducing argon for 10-15 min, then standing for 5-15 min, and removing floating slag on the surface of the melt; the mixed gas is a mixture of argon and hexachloroethane powder, wherein the concentration of hexachloroethane is 40-60 g/m³。

8. The method for preparing a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery according to claim 6, wherein: the casting and homogenizing annealing processes comprise: and continuously heating the melt obtained after degassing and slagging-off to 720-740 ℃ under the protection of argon, preserving heat for 5-20 min, then casting into a block-shaped cast ingot, and carrying out homogenizing annealing on the cast ingot at 550-600 ℃ for 12-24 h.

9. The method for preparing a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery according to claim 6, wherein: the rolling process comprises the following steps: and (3) hot rolling the cast ingot obtained by casting and homogenizing annealing to 3-5 mm at 300-400 ℃, and then cold rolling to finally obtain an anode plate with the thickness of 1-1.5 mm.

10. The method for preparing a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery according to claim 6, wherein: the solid solution process comprises the following steps: and carrying out solution treatment on the rolled anode plate at 400-600 ℃ for 4-12 h.

Technical Field

The invention relates to the field of metal-air batteries, in particular to a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery and a preparation method thereof.

Background

In recent years, research on metal-air batteries has been gradually a hot topic due to its extremely high theoretical energy density and specific capacitance, its discharge process is not strongly dependent on load and temperature, and its manufacturing cost is low, recyclability and environmental friendliness. The metal-air battery is a semi-fuel battery which takes metal as an anode, oxygen in air as a cathode and adopts neutral or alkaline electrolyte as a medium. The discharge principle is that the metal anode loses electrons to obtain electric energy.

Currently, metal-air batteries include lithium-air batteries, aluminum-air batteries, magnesium-air batteries, zinc-air batteries, and the like. Wherein the aluminum-air battery has a theoretical energy density of 8.1 kWh.kg^-1Second only to lithium-air batteries (13.0 kWh.kg)^-1) Higher than that of a magnesium-air battery (6.8 kWh.kg)^-1) And a zinc-air battery (1.3 kWh. kg)^-1). In addition, the aluminum anode has the advantages of rich resources, low manufacturing cost, easy processing and forming, no toxicity, high recoverability and the like. The lithium anode is relatively expensive and is prone to safety hazards due to its thermal instability. Therefore, aluminum-air batteries are expected to be sustainable, inexpensive, and high energy density electrochemical storage devices. Alkaline aluminum-air cells can provide higher and more stable operating potentials. However, pure aluminum anodes undergo severe hydrogen evolution corrosion in alkaline electrolytes, which reduces the discharge efficiency of the anode and causes voltage hysteresis during discharge, so that pure aluminum cannot be directly used as an anode material. In recent years, it has been found that by adding alloying elements to pure aluminum or to the electrolyteThe corrosion inhibitor can greatly improve the discharge performance of the anode material. At present, there are many patents and literature reports that alloy elements such as Ga, Sn, Mg, Zn, In, Hg, Pb, etc. are added into pure aluminum to improve the electrochemical performance of the aluminum anode. A plurality of anodes with better performance are obtained by adding alloy elements, such as Al-Ga-Mg, Al-In-Zn, Al-Zn-Hg, Al-In-Mg, Al-In-Sn, Al-Mg-Ga-Sn-Pb, Al-Ga-Sn-Mg-Mn (grant No. CN102820472B), Al-In-Ga-Zn (grant No. CN105140596B) and other alloys, but the components of the anodes contain noble elements such as In and Ga, which causes the production cost to be overhigh; in addition, Hg and Pb are harmful to the ecological environment. Therefore, the method has great significance in seeking an anode material which is low in cost, environment-friendly, good in discharge activity and low in self-corrosion rate.

Disclosure of Invention

The technical task of the invention is to provide an anode material for an alkaline aluminum-air battery, which has good discharge characteristics, low cost and environmental friendliness, and a preparation method thereof.

The invention provides a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery, which comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0 to 1.00%, Bi: 0-1.00%, less than or equal to 0.30% of impurity content, and the balance of Al.

Further, the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

Further, the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Bi: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

Further, the calcium-containing aluminum alloy anode material comprises the following components in percentage by mass: ca: 0.01 to 1.00%, Sn: 0.01 to 1.00%, Bi: 0.01-1.00%, impurity content less than or equal to 0.30%, and the balance of Al.

Further, the open-circuit voltage of the calcium-containing aluminum alloy anode material is 1.87-1.99V (Vs.SHE) and is 40mAcm^-2The discharge efficiency reaches 91.2-98.9% at the current density of (2), and the energy density is 3587.4-4037.7 Wh.kg^-1。

The invention also provides a preparation method of the calcium-containing aluminum alloy anode material for the alkaline aluminum-air battery based on the components, the calcium-containing aluminum alloy anode material is prepared by smelting, degassing, slagging off, casting, homogenizing annealing, rolling and solid solution, wherein the smelting process comprises the following steps: proportioning according to alloy components, adding industrial pure aluminum into a medium-frequency smelting furnace, heating to 760-790 ℃ for melting, controlling the temperature to 720-750 ℃, adding an aluminum-calcium intermediate alloy into the melt, electromagnetically stirring the melt for 5-30 min when the aluminum-calcium intermediate alloy is completely melted, controlling the temperature to 670-720 ℃ after the electromagnetic stirring if the alloy components contain low-melting-point alloy elements, adding the low-melting-point alloy elements, and electromagnetically stirring the melt for 5-15 min after the low-melting-point alloy elements are melted; the low-melting-point alloy element is Sn and/or Bi.

Further, the degassing and slagging-off process comprises the following steps: introducing the melt obtained after smelting into a standing furnace at 730-750 ℃, introducing mixed gas into the standing furnace for 5-10 min, introducing argon for 10-15 min, then standing for 5-15 min, and removing floating slag on the surface of the melt; the mixed gas is a mixture of argon and hexachloroethane powder, wherein the concentration of hexachloroethane is 40-60 g/m³。

Further, the casting and homogenizing annealing process comprises the following steps: and continuously heating the melt obtained after degassing and slagging-off to 720-740 ℃ under the protection of argon, preserving heat for 5-20 min, then casting into a block-shaped cast ingot, and carrying out homogenizing annealing on the cast ingot at 550-600 ℃ for 12-24 h.

Further, the rolling process comprises: and (3) hot rolling the cast ingot obtained by casting and homogenizing annealing to 3-5 mm at 300-400 ℃, and then cold rolling to finally obtain an anode plate with the thickness of 1-1.5 mm.

Further, the solid solution process comprises: and carrying out solution treatment on the rolled anode plate at 400-600 ℃ for 4-12 h.

The invention discloses a preferable technical scheme of a preparation method of a calcium-containing aluminum alloy anode material for an alkaline aluminum-air battery, which comprises the following steps:

(1) preparing materials: taking industrial pure aluminum, industrial pure tin, industrial pure bismuth and aluminum calcium intermediate alloy as raw materials, and batching according to alloy components;

(2) smelting: in the smelting process, firstly adding industrial pure aluminum into a medium-frequency smelting furnace, heating to 760-790 ℃ for melting, controlling the temperature to 720-750 ℃, adding an aluminum-calcium intermediate alloy into the melt, electromagnetically stirring the melt for 5-30 min when the intermediate alloy is completely melted, controlling the temperature to 670-720 ℃ after the electromagnetic stirring if the alloy components contain low-melting-point alloy elements, adding the low-melting-point alloy elements, electromagnetically stirring the melt for 5-15 min after the low-melting-point alloy elements are melted, and introducing argon as a protective gas in the whole smelting process; the low-melting-point alloy element is Sn and/or Bi, and the low-melting-point alloy element is pressed in by a bell jar in an aluminum foil coating mode for 2-4 min;

(3) degassing and slagging off: introducing the melt obtained in the step (2) into a standing furnace at 730-750 ℃, introducing mixed gas into the standing furnace for 5-10 min, introducing argon for 10-15 min, standing for 5-15 min, and removing floating slag on the surface of the melt by using a graphite tool, wherein the mixed gas is a mixture of argon and hexachloroethane powder (the hexachloroethane concentration is 40-60 g/m)³)；

(4) Pouring: continuously heating the melt obtained in the step (3) to 720-740 ℃ under the protection of argon, preserving heat for 5-20 min, then casting into a block-shaped cast ingot, and carrying out homogenizing annealing on the cast ingot at 550-600 ℃ for 12-24 h;

(5) rolling: hot rolling the cast ingot obtained in the step (4) to 3-5 mm at 300-400 ℃, and then finally rolling the cast ingot into an anode plate with the thickness of 1-1.5 mm through cold rolling;

(6) solid solution: and (4) carrying out solution treatment on the anode plate obtained in the step (5) at 400-600 ℃ for 4-12 h.

The invention adopts binary or ternary alloy as the anode material of the alkaline aluminum-air battery, wherein trace Ca in the aluminum alloy is beneficial to reducing the tendency of over-activation of the anode and is beneficial to displaying better voltage recovery after the precipitation of aluminum hydroxide; in addition, calcium is an environmentally friendly element, and its standard electrode potential is higher than that of aluminum (-2.35V (vs. she)), i.e., -3.02V (vs. she), in an alkaline solution, and can improve the discharge voltage of an aluminum anode. Sn in the aluminum alloy can activate the anode through the principle of dissolution-redeposition; meanwhile, the alloy element Sn has higher hydrogen overpotential, so that the hydrogen evolution corrosion can be inhibited, and the effective utilization rate of the alloy is increased. The alloy element Bi can expand the crystal lattice of the aluminum alloy, so that the solid solubility of other alloy elements is increased, the passivation performance of the surface of the aluminum alloy can be reduced, and the utilization rate of the anode is improved; bi can also reduce the nonuniformity of the anode microstructure and improve the current efficiency; in addition, Bi element has the advantages of low price and relative innocuity.

The invention has the beneficial effects that:

1. the anode material adopts industrial pure aluminum as a raw material, does not contain valuable elements such as In and Ga, does not contain elements such as Pb and Hg which are harmful to the environment, contains Ca which can refine crystal grains and improve the electrochemical performance of the anode, reduces the production cost, simultaneously maintains the activity of the anode, and the alloy element Sn has higher hydrogen overpotential, can inhibit hydrogen evolution corrosion and increase the effective utilization rate of the alloy;

2. according to the preparation method, the anode material is processed into the anode plate which can be directly used at any time by adopting a rolling process, the process is simple, the method is suitable for batch production, the defects of the anode material are reduced, the yield is improved, the energy consumption is reduced, the production cost is reduced, and good economic benefits are achieved;

3. according to the anode material, through a solid solution process after rolling, the solid solubility of each alloy element is increased, and the formation of segregation phase is reduced, so that the discharge characteristics (discharge efficiency, energy density and specific capacitance) of the anode are greatly improved, and the open-circuit potential of the aluminum alloy anode is 1.87-1.99V (Vs.SHE) in 4mol/L NaOH electrolyte; at 40mA cm^-2The discharge efficiency and the energy density respectively reach 91.2-98.9% and 3587.4～4037.7Wh·kg^-1And the problems of serious hydrogen evolution corrosion, serious polarization, voltage hysteresis and the like are solved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified, and the raw materials in the examples have a purity of, in terms of mass fraction, 99.8% of commercially pure aluminum Al, 99.9% of commercially pure tin Sn, 99.9% of commercially pure bismuth Bi, and 75% of Ca in an aluminum-calcium master alloy.

Table 1 composition (mass%) of the calcium-containing aluminum alloy anode material in each example