Alkaline aluminum-air battery electrolyte, preparation method thereof and alkaline aluminum-air battery
By adding mercaptosuccinic acid as an additive to the electrolyte of aluminum-air batteries, a stable polymer film is formed, which solves the problems of aluminum electrode corrosion and hydrogen evolution, improves the energy density and anode utilization of aluminum-air batteries, and realizes the construction of high-performance aluminum-air batteries.
Patent Information
- Application Number
- CN202511828334.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-05
- Publication Date
- 2026-02-24
AI Technical Summary
The aluminum electrodes of aluminum-air batteries are prone to corrosion, have low cycle life, and rapid capacity decay, resulting in unsatisfactory anode utilization.
Mercaptosuccinic acid was used as an additive to prepare an alkaline aluminum-air battery electrolyte by adding it to an alkaline solution. The concentration of mercaptosuccinic acid was 5 mM. It formed a stable polymer solid electrolyte interface film, which covered the aluminum anode surface and inhibited self-corrosion and hydrogen evolution reaction.
The energy density and anode utilization rate of the aluminum-air battery have been significantly improved. The energy density of the aluminum-air battery has been increased to 2790.7 mWh g-1, and the anode utilization rate has reached 78.1%, while the cost has been reduced and environmental protection requirements have been met.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology, and particularly relates to an alkaline aluminum-air battery electrolyte and its preparation method, as well as an alkaline aluminum-air battery. Background Technology
[0002] Next-generation batteries with high energy density, capacity, and safety have attracted significant research interest. Aluminum-air batteries (AAB) have emerged as a promising candidate for next-generation energy storage / conversion systems, surpassing lithium-ion batteries, due to their cost-effectiveness and impressive theoretical energy density of 8100 Wh / kg.
[0003] However, the practical applicability of AABs is hampered by severe self-corrosion side reactions and significant capacity loss, resulting in unsatisfactory anode utilization. Therefore, improving anode utilization to promote the construction of high-performance AABs has attracted widespread attention.
[0004] However, the strongly alkaline electrolyte used in traditional aluminum-air batteries corrodes the aluminum anode, leading to passivation of the electrode surface and severe hydrogen evolution problems, resulting in rapid capacity decay and significantly limiting the development and application of aluminum-air batteries. Therefore, developing a novel electrolyte to inhibit aluminum anode corrosion is crucial for constructing high-performance aluminum-air batteries. Summary of the Invention
[0005] The purpose of this invention is to provide an alkaline aluminum-air battery electrolyte that can solve the technical problems of current aluminum-air batteries, such as easy corrosion of aluminum electrodes, low cycle life, and rapid capacity decay.
[0006] To achieve the above objectives, the present invention provides an alkaline aluminum-air battery electrolyte, comprising an additive and an alkaline solution, wherein the additive is mercaptosuccinic acid, wherein the mass percentage of the additive is 0.01-10%, and the molar concentration of the alkaline solution is 0.1 mol / L-10 mol / L.
[0007] The alkaline solution is an aqueous solution of potassium hydroxide, sodium hydroxide, or lithium hydroxide.
[0008] The concentration of the mercaptosuccinic acid is 1 mM-7 mM.
[0009] The concentration of the mercaptosuccinic acid is 5 mM. A method for preparing an alkaline aluminum-air battery electrolyte involves adding mercaptosuccinic acid to an alkaline solution and stirring to dissolve it, thereby obtaining the alkaline aluminum-air battery electrolyte.
[0010] An alkaline aluminum-air battery includes an air electrode and a metallic aluminum electrode, and also uses the alkaline aluminum-air battery electrolyte.
[0011] The use of mercaptosuccinic acid in the preparation of the alkaline aluminum-air battery electrolyte, which is used to inhibit the self-corrosion and hydrogen evolution reaction of the aluminum anode and improve the anode utilization rate.
[0012] Beneficial effects: The polar groups (-OH, -COOH, SH) of the additive mercaptosuccinic acid in this invention can preferentially adsorb onto the metal surface, effectively covering the HER sites, significantly inhibiting self-corrosion and hydrogen evolution of the aluminum anode, and optimizing the distribution of discharge products. This achieves a high energy density (2790.7 mWh g⁻¹) in the aluminum-air battery, and also improves the electrochemical performance of the aluminum-air battery, increasing anode utilization rate to as high as 78.1%. The electrolyte and its additives proposed in this invention have a simple composition, low cost, are safe, and meet environmental protection requirements, avoiding the use of rare heavy metal ions and harmful substances. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the aluminum-air battery system structure used in an embodiment of the present invention; Figure 2 The diagram shows the open-circuit voltage (OCP) test results of the 5052 grade aluminum alloy of this invention in sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid. Figure 3 This is a test graph showing the polarization (Tafel) curves of the 5052 grade aluminum alloy of the present invention in sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid. Figure 4 The electrochemical impedance spectroscopy (EIS) test results of the 5052 grade aluminum alloy of this invention in sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid are shown. Figure 5 This is a LSV test diagram of the alkaline aluminum-air battery of the present invention; Figure 6 This is a constant current discharge test diagram of the alkaline aluminum-air battery of the present invention; Figure 7 This is a test diagram of the intermittent discharge of the alkaline aluminum-air battery of the present invention; Figure 8 This is a stepped discharge test diagram of the alkaline aluminum-air battery of the present invention; Figure 9 This is a graph showing the hydrogen evolution volume results of sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid in this invention. Figure 10 The graph shows the results of hydrogen evolution rate and inhibition of hydrogen evolution rate using sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid according to the present invention. Figure 11 A comparison of the battery performance of alkaline aluminum-air batteries at a current density of 20 mA cm⁻². Detailed Implementation
[0014] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared using conventional methods in the art. Specific details not described in the following embodiments can be achieved using conventional experimental methods in the art.
[0015] Electrochemical experiments were conducted using a three-electrode system, with a platinum electrode as the auxiliary electrode and an Hg / HgO electrode as the reference electrode. The working electrode was sealed with epoxy resin, leaving 1 cm exposed. 2 The working surface was then sanded (400-2000 grit), ultrasonically degreased with alcohol, rinsed with deionized water, and air-dried. Electrochemical tests were performed on the Chenhua 760E testing system.
[0016] Example 1 An alkaline aluminum-air battery electrolyte comprises sodium hydroxide and an additive, wherein the additive is mercaptosuccinic acid; the electrolyte is prepared by: (1) Prepare 200 mL of a 4 M sodium hydroxide aqueous solution and cool it to room temperature; (2) Add mercaptosuccinic acid to the above sodium hydroxide aqueous solution to make its concentration reach 1 mM, and stir for 10 min until completely dissolved. Under the conditions of Example 1, the hydrogen evolution efficiency (10.7%) and corrosion inhibition efficiency (15.4%) of the aluminum block in the electrolyte are relatively low.
[0017] Example 2 The difference between this embodiment and Example 1 is that the concentration of mercaptosuccinic acid is 3 mM, while other conditions remain unchanged. Compared with the conditions of Example 1, the improvement in hydrogen evolution inhibition efficiency (21.5%) and corrosion inhibition efficiency (20.9%) of the aluminum block in the electrolyte is relatively low in Example 2.
[0018] Example 3 The difference between this example and Example 1 is that the concentration of mercaptosuccinic acid is 5 mM, while other conditions remain unchanged. Example 3 shows a significant and substantial improvement in hydrogen evolution inhibition efficiency (47.6%) and corrosion inhibition efficiency (46.6%) in the electrolyte compared to Examples 1 and 2.
[0019] Example 4 The difference between this embodiment and Example 1 is that the concentration of mercaptosuccinic acid is 7 mM, while other conditions remain unchanged. However, compared with Example 3, the efficiency of hydrogen evolution inhibition (38.4%) and corrosion inhibition efficiency (25.9%) in the electrolyte are significantly reduced under these conditions.
[0020] Therefore, compared with other embodiments, under the same conditions, when the concentration of mercaptosuccinic acid was 5 mM, the aluminum block achieved the best hydrogen evolution inhibition efficiency (47.6%) in the electrolyte. Subsequent tests verified that the corrosion inhibition efficiency (46.6%) and battery performance were also optimal.
[0021] A method for preparing an alkaline electrolyte for an aluminum-air battery is as follows: (1) Prepare 200 mL of a 4 M sodium hydroxide aqueous solution and cool it to room temperature.
[0022] Experimental testing 1. Three-electrode test The electrolytes prepared in Examples 1, 2, 3, 4, and Comparative Example 1 were poured into different electrolytic cells for three-electrode testing. The three-electrode tests primarily measured open-circuit voltage (OCP), electrochemical impedance spectroscopy (EIS), and polarization curves (Tafel). The OCP test duration was 1800 s; the EIS spectroscopy frequency was 1-10. 5 The impedance measurement signal amplitude is 5 mV sine wave at Hz; the Tafel curve scan rate is 1 mV / min, and the scan range is ±300 mV relative to the open circuit potential.
[0023] An electrochemical experiment on an alkaline aluminum-air battery electrolyte includes the following steps: The pretreated 5052 grade aluminum alloy electrode was placed in the prepared electrolyte and the open circuit potential was tested for 1800 s to stabilize the electrode potential. Then, Tafel curve test and EIS test were performed.
[0024] Corrosion inhibition efficiency ( η i %) is calculated using the following formula: in, i corr and i corr(inh) Corrosion current densities of 5052 grade aluminum alloys before and after additive treatment, respectively.
[0025] By extending the cathodic and anodic branches of the Tafel curve, we obtained the corrosion potential ( E corr), the Tafel constant of the cathode and anode ( βc , β a ) and corrosion inhibition efficiency ( η i The relevant parameters are summarized in Table 1. The polarization curve fitting parameters of the aluminum electrode in sodium hydroxide solutions containing different concentrations of mercaptosuccinic acid are shown in Table 1.
[0026] Table 1 E corr , β c、 β a These represent corrosion potential, anodic Tafel slope, and cathodic Tafel slope, respectively. As shown in Table 1, the corrosion inhibition efficiency of the blank is lower than that of the aluminum electrode with added mercaptosuccinic acid. Moreover, the corrosion inhibition rate of the aluminum electrode by the additive increases with the increase of the additive concentration. When the concentration of mercaptosuccinic acid is 5mM, the corrosion inhibition rate is the largest, with an optimal corrosion inhibition rate of 46.6%. Therefore, the present invention preferably uses 5mM mercaptosuccinic acid, as the additive at this concentration has the best corrosion inhibition effect on aluminum.
[0027] like Figure 2 As shown, the open-circuit potential of the aluminum electrode in the electrolyte containing additives is 1.511 V, while the open-circuit voltage in the electrolyte containing mercaptosuccinic acid additives is the largest.
[0028] like Figure 3 As shown, the cathode and anodic corrosion current densities of aluminum electrodes in electrolytes containing additives both decrease, and the potentials shift in the negative direction. This indicates that the mercaptosuccinic acid additive mainly reduces the self-corrosion hydrogen evolution reaction of aluminum by adsorbing onto the active sites of the aluminum electrode. The negatively charged mercaptosuccinic acid groups can be adsorbed on the surface of the aluminum anode to form a stable polymer solid electrolyte interface film. This polymer film helps protect the aluminum anode from corrosion by strongly alkaline electrolytes, effectively solving the surface passivation problem of the aluminum anode during cycling, thereby improving the cycle performance of aluminum-air batteries.
[0029] like Figure 4 As shown, the aluminum electrode exhibits the smallest capacitive arc in the blank solution. The capacitive arc increases with the addition of different concentrations of additives, demonstrating that the additives effectively inhibit corrosion. The aluminum electrode shows the largest capacitive arc when the concentration of mercaptosuccinic acid is 5 mM. This indicates that the additive provides the best protective effect at this concentration.
[0030] 2. Aluminum-air battery testing The electrolytes from Example 3 and Comparative Example 1 were used in the preparation of aluminum-air batteries, and the performance of the aluminum-air batteries was tested. An experiment on the performance of an alkaline aluminum-air battery containing the electrolytes included the following steps: like Figure 5 As shown, the LSV polarization of the pretreated 5052 grade aluminum alloy anode in the Blank electrolyte and mercaptosuccinic acid prepared in this embodiment was tested using an electrochemical workstation. The test voltage range was 0 V - 2 V (vs. Hg / HgO). This test reflects the power density and polarization curve of the aluminum-air battery.
[0031] With the addition of additives to the electrolyte, aluminum-air batteries exhibit lower polarization and higher power density. The overall power density of the aluminum-air battery containing the additive-containing electrolyte is 61.8 mW / cm². -2 Significantly higher than the 28.2 mW cm⁻¹ of the additive-free electrolyte. -2 .
[0032] like Figure 6 As shown, the pretreated 5052 grade aluminum alloy anode was tested using an electrochemical workstation in the Blank electrolyte and mercaptosuccinic acid prepared in Example 3, with constant current discharge at 20 mA cm⁻¹. -2 The battery was tested at a constant current density for 1 hour. The mass difference of the aluminum block before and after discharge was calculated to reflect the battery's capacity density.
[0033] Aluminum-air batteries tested using additive electrolyte at 20 mA cm⁻¹ -2 The capacity density is 2325.6 mAhg. -1 It is an additive-free electrolyte (1176.4 mAh g). -1 The energy density was twice that of the test result. It also increased from 1317.6 mWh / g. -1 Increased to 2790.7 mWh g -1 The anode utilization rate of aluminum-air batteries tested using additive electrolytes reached as high as 78.1%.
[0034] Bulk density is calculated using the following formula: in, Q Capacity density (mAh g) -1 ), I Current density (mA cm) -2 ), t For time (h), Δ m The mass difference (g) of the aluminum anode before and after the constant current test.
[0035] Energy density is calculated using the following formula: in, W Energy density (mWh g) -1 ), E It is the average discharge voltage (V). I Current density (mA cm) -2 ), t For time (h), Δ m The mass difference (g) of the aluminum anode before and after the constant current test.
[0036] Anode utilization rate is calculated using the following formula: in, U a represents the anode utilization rate (%). I The discharge current density is (A). t Δ is the discharge time (s). m The mass difference (g) of the aluminum anode before and after the constant current test. F Faraday constant (96485 C·mol) -1 ).
[0037] like Figure 7 As shown, the intermittent discharge of the pretreated 5052 grade aluminum alloy anode in the Blank electrolyte and mercaptosuccinic acid prepared in this embodiment was tested using an electrochemical workstation. First, the voltage of the aluminum-air battery under a constant current discharge of 20 mA for 60 min was tested, followed by an open-circuit voltage test for 20 min. This constitutes one cycle. Through the cyclic testing of the aluminum-air battery, the stability of its discharge performance can be observed.
[0038] The aluminum-air battery tested in Example 3 showed higher voltage at 20 mA and higher open-circuit voltage than that of Comparative Example 1. This indicates that the aluminum-air battery containing additive electrolyte has better and more stable discharge performance.
[0039] like Figure 8 As shown, the pretreated 5052 grade aluminum alloy anode was tested in the electrolyte of Comparative Example 1 and Example 3 using an electrochemical workstation for stepped discharge. The overall performance of the aluminum-air battery was judged by testing the voltage stability at different currents of 1 mA, 10 mA, 20 mA, 40 mA, 60 mA, 80 mA, 100 mA and 120 mA. Each current test lasted for 600 s. This test can show whether the aluminum-air battery can discharge stably under high current discharge.
[0040] At 20 mA cm -2 At the circuit density, the voltage of the electrolyte containing additives is significantly higher than that of the aluminum-air battery without additives, while at 100 mA cm⁻¹... -2and 120 mA cm -2 At higher current densities, the discharge voltage of aluminum-air batteries containing electrolytes tends to be unstable. This is because higher current densities affect the adsorption of additives on the aluminum surface, thereby reducing the discharge performance of aluminum-air batteries.
[0041] 3. Hydrogen evolution test The reaction area is 1 cm² 2 5052 grade aluminum blocks were placed in the electrolytes of Example 1, Example 2, Example 3, Example 4, and Comparative Example 1, respectively. The temperature of the electrolyte was kept constant at 25°C. The H2 generated by the self-corrosion of the aluminum blocks was recorded every 5 minutes using the water displacement gas collection method for a total of 30 minutes.
[0042] like Figure 9 As shown, the electrolyte containing the additive mercaptosuccinic acid has a lower H2 precipitation volume in the same amount of time.
[0043] like Figure 10 As shown, the hydrogen evolution rate of Comparative Example 1 was 0.65 mL cm⁻¹. -2 min -1 The hydrogen evolution efficiency of the electrolyte in Example 3 was significantly lower, at 0.34 mL cm⁻¹. -2 min -1 The corresponding hydrogen evolution inhibition efficiency also reached 47.6%.
[0044] hydrogen evolution rate ( Calculate using the following formula: in, This represents the volume of hydrogen evolution (mL). A Reaction area (cm²) 2 ), T The hydrogen evolution time (min) is used. Suppressing hydrogen evolution efficiency ( Calculate using the following formula: in, The hydrogen evolution rate of Blank electrolyte. The hydrogen evolution rate is the rate of hydrogen evolution in the electrolyte containing additives.
[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
[0046] It should be understood that the above description of the preferred embodiments is quite detailed, but it should not be considered as a limitation on the scope of protection of this invention. Those skilled in the art, under the guidance of this invention, can make substitutions or modifications without departing from the scope of protection of the claims of this invention, and all such substitutions or modifications fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.
Claims
1. An alkaline aluminum-air battery electrolyte, characterized in that, The mixture includes an additive and an alkaline solution, wherein the additive is mercaptosuccinic acid, the mass percentage of the additive is 0.01-10%, and the molar concentration of the alkaline solution is 0.1 mol / L-10 mol / L.
2. The alkaline aluminum-air battery electrolyte according to claim 1, characterized in that, The alkaline solution is an aqueous solution of potassium hydroxide, sodium hydroxide, or lithium hydroxide.
3. The alkaline aluminum-air battery electrolyte according to claim 1, characterized in that, The concentration of the mercaptosuccinic acid is 1 mM-7 mM.
4. The alkaline aluminum-air battery electrolyte according to claim 3, characterized in that, The concentration of the mercaptosuccinic acid is 5 mM.
5. A method for preparing an alkaline aluminum-air battery electrolyte as described in any one of claims 1-4, characterized in that, The alkaline aluminum-air battery electrolyte is prepared by adding mercaptosuccinic acid to an alkaline solution and stirring to dissolve it.
6. An alkaline aluminum-air battery, comprising an air electrode and a metallic aluminum or aluminum alloy electrode, characterized in that, The alkaline aluminum-air battery electrolyte according to any one of claims 1-4 is also used.
7. Use of mercaptosuccinic acid in the preparation of the alkaline aluminum-air battery electrolyte as described in claim 1, wherein the alkaline aluminum-air battery electrolyte is used to inhibit the self-corrosion and hydrogen evolution reaction of the aluminum anode and to improve the anode utilization rate.