Application of pyridine derivative in aluminum air battery electrolyte, electrolyte and aluminum air battery

Abstract

The invention relates to the field of batteries, and discloses an application of a pyridine derivative in an aluminum air battery electrolyte, the electrolyte and an aluminum air battery, and in the application, the adopted pyridine derivative has a pyridine ring, a sulfydryl group and a carboxylic acid group, and the pyridine derivative is used as an aluminum corrosion inhibitor. The pyridine ring, the sulfydryl and the carboxylic acid group of the pyridine derivative cooperate together to construct a stable protective layer on an AABs electrode / electrolyte interface and inhibit direct contact between H2O molecules and the surface of an Al electrode, so that the self-corrosion of an aluminum anode is effectively inhibited, the hydrogen evolution rate of the aluminum anode is reduced, and the purposes of increasing the energy density and improving the discharge performance of the battery are achieved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to application of a pyridine derivative in an electrolyte of an aluminum-air battery, and the electrolyte and the aluminum-air battery. Background Art

[0002] The current global energy structure is seeking transformation, and it is imperative to develop new energy storage technologies that combine high energy density, environmental compatibility, and long-term stability. As an important component of the new energy storage system, aluminum-air batteries (AABs) have a high energy density of 8100Whkg. -1 Its ultra-high theoretical energy density, abundant aluminum resources, and environmentally friendly properties have made it a leading candidate for industrial applications. It possesses unique competitiveness in applications such as electric vehicle range extension systems, grid energy storage, and low-altitude aircraft power supplies.

[0003] However, its industrialization faces multiple scientific challenges. In alkaline electrolytes, aluminum anode surface passivation and self-corrosion caused by the hydrogen evolution side reaction lead to reduced actual energy density, lower discharge voltage, and a sharp drop in anode utilization. To address these bottlenecks, the development of highly efficient corrosion inhibitors has become a key breakthrough direction.

[0004] While traditional inorganic corrosion inhibitors can partially inhibit aluminum corrosion, they generally face bottlenecks such as low cost-effectiveness and poor environmental compatibility. In contrast, organic corrosion inhibitors, with their advantages such as strong molecular structure tunability, high solubility, and environmental friendliness, have become a research focus in the field of metal corrosion protection. In the AABs system, organic corrosion inhibitors primarily inhibit corrosion through the directional adsorption of polar groups and the coordinated regulation of metal deposition to form a protective barrier, or by reconstructing hydrogen bond networks to reduce interfacial water activity, thereby exhibiting corrosion inhibition.

[0005] In view of the limitations of traditional single-action mechanism such as insufficient adsorption strength and poor environmental adaptability, it is very important to develop a new corrosion inhibitor to improve this problem. Summary of the Invention

[0006] The present invention aims to overcome the insufficient corrosion inhibition efficiency of existing corrosion inhibitors by providing a pyridine derivative for use in an aluminum-air battery electrolyte, as well as an electrolyte and an aluminum-air battery. The pyridine ring, thiol, and carboxyl groups of the pyridine derivative employed in the present invention work together to form a stable protective layer at the AABs electrode / electrolyte interface, inhibiting direct contact between H2O molecules and the Al electrode surface.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a use of a pyridine derivative in an aluminum-air battery electrolyte, wherein the pyridine derivative has a pyridine ring, a thiol group and a carboxylic acid group.

[0008] The pyridine ring, thiol and carboxylic acid groups of the pyridine derivative work together to build a stable protective layer at the AABs electrode / electrolyte interface, inhibiting the direct contact between H2O molecules and the Al electrode surface, thereby effectively inhibiting the self-corrosion of the aluminum anode and reducing its hydrogen evolution rate, thereby achieving the purpose of increasing its energy density and improving the battery discharge performance.

[0009] A second aspect of the present invention provides an electrolyte, wherein the electrolyte comprises a solute, a solvent and an additive, wherein the solvent comprises a strong base, and the additive comprises a pyridine derivative having a pyridine ring, a thiol group and a carboxylic acid group.

[0010] The third aspect of the present invention provides an aluminum-air battery comprising the electrolyte described in the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the Nyquist fitting spectrum when Examples 1-4 and Comparative Example 1 are assembled into a three-electrode system;

[0012] Figure 2 The electrochemical Bode fitting spectra of Examples 1-4 and Comparative Example 1 include impedance-frequency and phase angle-frequency plots;

[0013] Figure 3 1 is a polarization curve diagram of Examples 1-4 and Comparative Example 1;

[0014] Figure 4 1 is an electrochemical window diagram of Examples 1-4 and Comparative Example 1;

[0015] Figure 5 1 is a graph of hydrogen evolution volume for Examples 1-4 and Comparative Example 1;

[0016] Figure 6 Graph showing the hydrogen evolution rate and hydrogen evolution inhibition efficiency of Examples 1-4 and Comparative Example 1;

[0017] Figure 7 The full cells assembled in Example 5 and Comparative Example 2 were tested at a current density of 20 mA cm -2 The constant current discharge curve diagram below;

[0018] Figure 8 1 is a graph showing the polarization curves and power density curves of the full batteries assembled in Example 5 and Comparative Example 2;

[0019] Figure 9 is an intermittent discharge curve diagram of the full battery assembled in Example 5 and Comparative Example 2;

[0020] Figure 10 1 is a voltage curve diagram of the full battery assembled in Example 5 and Comparative Example 2 at different current densities;

[0021] Figure 11 1 is a long-term cycle stability curve of the full batteries assembled in Example 5 and Comparative Example 2;

[0022] Figure 12 is a SEM image of an aluminum sample immersed in the solution prepared in Comparative Example 1 for 1 h;

[0023] Figure 13 is a SEM image of an aluminum sample immersed in the solution prepared in Example 3 for 1 h;

[0024] Figure 14 is a CLSM image obtained by immersing the aluminum sample in the solution prepared in Comparative Example 1 for 1 h;

[0025] Figure 15 is a CLSM image obtained when the aluminum sample was immersed in the solution prepared in Example 3 for 1 h;

[0026] Figure 16 is the contact angle graph obtained when the aluminum sample was immersed in the solution prepared in Comparative Example 1 for 1 hour;

[0027] Figure 17 is the contact angle graph obtained when the aluminum sample was immersed in the solution prepared in Example 3 for 1 h;

[0028] Figure 18 This is a schematic diagram of the assembly of a full battery device. DETAILED DESCRIPTION

[0029] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0031] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0032] In addition, the term "and / or" in the specification and claims is used to describe an association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0033] A first aspect of the present invention provides an application of a pyridine derivative in an aluminum-air battery electrolyte, wherein the pyridine derivative has a pyridine ring, a thiol group and a carboxylic acid group, and the pyridine derivative is used as an aluminum corrosion inhibitor.

[0034] Preferably, the pyridine derivative includes 2-mercapto-3-pyridinecarboxylic acid.

[0035] A second aspect of the present invention provides an electrolyte, wherein the electrolyte includes a solute, a solvent and an additive, wherein the solute includes a strong base, and the additive includes a pyridine derivative having a pyridine ring, a thiol group and a carboxylic acid group.

[0036] Preferably, the pyridine derivative includes 2-mercapto-3-pyridinecarboxylic acid. 2-Mercapto-3-pyridinecarboxylic acid (MPA) can promote the expansion of the electrochemical window and improve the stability of the electrolyte.

[0037] Preferably, the concentration of the pyridine derivative is 1-15 mM based on the total amount of the electrolyte.

[0038] Preferably, the concentration of the pyridine derivative is 8-10 mM based on the total amount of the electrolyte.

[0039] The concentration of the pyridine derivative can be 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 8 mM, 10 mM, 12 mM, 15 mM, and any value between any two of these numbers.

[0040] The concentration of pyridine derivatives is directly related to the corrosion inhibition rate of Al anode. Generally speaking, as the concentration of pyridine derivatives increases, the corrosion inhibition rate increases and the hydrogen evolution rate decreases. When the concentration is 10 mM, the hydrogen evolution rate is as low as 0.19 mL·min. -1 cm -2At this time, the coverage and density of the adsorption layer reach the optimal synergy, and the corrosion inhibition effect is the best.

[0041] Preferably, the strong base comprises sodium hydroxide and / or potassium hydroxide. Sodium hydroxide is an ideal electrolyte for aluminum-air batteries, offering superior performance compared to potassium hydroxide. This is primarily due to its lower corrosiveness towards common battery structural materials such as stainless steel and carbon steel, which helps reduce battery casing protection costs and extend battery system life. NaOH also offers significant advantages in affordability and ease of use, as well as lower ecotoxicity.

[0042] Preferably, based on the total amount of the electrolyte, the concentration of the strong base is 3-5 M (such as 3 M, 4 M, 5 M and any value between any two numbers thereof).

[0043] Preferably, the concentration of the strong base is 4M.

[0044] Preferably, the solvent is deionized water.

[0045] Preferably, the electrolyte consists of a solute, a solvent and an additive, wherein the solute is sodium hydroxide, the additive is 2-mercapto-3-pyridinecarboxylic acid, the solvent is deionized water, and based on the total amount of the electrolyte, the concentration of the 2-mercapto-3-pyridinecarboxylic acid is 8-10mM, and the concentration of the sodium hydroxide is 3-5M, preferably 4M.

[0046] The third aspect of the present invention provides an aluminum-air battery comprising the electrolyte described in the second aspect of the present invention.

[0047] The present invention uses MPA as an electrolyte additive. The MPA molecules achieve interfacial stability through multi-center adsorption. The pyridine ring, thiol group, and carboxyl group in the MPA molecules work together to build a stable protective layer at the AABs electrode / electrolyte interface, inhibiting direct contact between H2O molecules and the Al electrode surface. The addition of MPA can also promote the expansion of the electrochemical window and improve the stability of the electrolyte.

[0048] The present invention found that as the concentration of MPA increases, i corr Gradually decreased, when the MPA concentration was 10mM, i corr The blank (no MPA added) has a value of 25.37 mA cm -1 down to 13.68 mA cm -1 The corrosion inhibition efficiency reached 46.08%, and the total resistance increased by 40.8%. Compared with the blank group, when MPA was 10 mM, the hydrogen evolution rate increased from 0.33 mL min to -1 cm -2 Reduced to 0.19 mL min -1 cm -2This shows that when the electrolyte is used on the surface of aluminum anode, it can effectively inhibit the self-corrosion of aluminum anode and reduce its hydrogen evolution rate.

[0049] The aluminum-air battery assembled with the electrolyte provided by the present invention can achieve a capacity density of up to 1379.3 mA·h·g -1 , the energy density can be as high as 1601.8Wh kg -1 , the power density reaches 63.56mW cm -2 Compared with the case without MPA, the stable discharge time of the battery increased from 26h to 44h. This shows that when this electrolyte is used in aluminum-air batteries, it can increase the discharge time of the aluminum anode and effectively improve the discharge performance of aluminum-air batteries.

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] 1. Test Materials

[0052] The open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and polarization curve (PDP) were measured using the first three-electrode system. The working electrode (WE) in the first three-electrode system was prepared by: 3 A pure aluminum cube was welded to a 2mm diameter copper wire. After testing its good conductivity, it was placed on a table. A PVC tube of appropriate height was placed on the outer layer. The gaps were filled with epoxy resin. After curing, the bottom was polished with sandpaper and it was ready for use. The reaction area at this time was controlled to be 1.0cm 2 , the counter electrode (CE) is 2.0cm 2 Platinum sheet, and Hg / HgO electrode was used as reference electrode (RE).

[0053] The electrochemical window test was performed using a second three-electrode system, in which the working electrode and the counter electrode were both platinum electrodes, and the reference electrode was a Hg / HgO electrode.

[0054] The aluminum substrate used in the hydrogen evolution test and immersion corrosion test was commercially pure Al (99.99%), which was polished with 400, 800, 1200, 1500 and 2000 grit sandpaper in sequence, and then ultrasonically cleaned with anhydrous ethanol and deionized water in sequence, and finally dried at room temperature to obtain pretreated Al samples.

[0055] The test temperature of this application is: 25±1℃.

[0056] The full cell device was assembled as follows: the anode was commercially pure Al (99.99%) (purchased from Qinghe County Runde Metal Materials Co., Ltd.), and the cathode was a commercial air cathode (composed of a waterproof and breathable membrane, a current collecting layer, and a Mn2O3-based catalytic layer. The full cell device and cathode-related materials were purchased from Changsha Spring New Energy Technology Co., Ltd.). The specific assembly method was as follows: Figure 18 As shown, a cut aluminum sheet (as an anode, as shown in 18(a)) is placed between the four screws on the bottom plate (numbered 1 in the figure), and the aluminum sheet does not touch the screws. The anode gasket, the middle plate (numbered 2 in the figure), and the cathode gasket are placed in sequence as shown in Figure 18 As shown in (b)-(c), Figure 18 (d)-(e) Then put the air cathode and the top plate (numbered 3 in the figure), and finally put the gasket and nut, and tighten the device. The final device is as follows Figure 18 As shown in (f), in the device, the stacking relationship of the various components is specifically: bottom plate, aluminum sheet (anode), anode gasket, middle plate, cathode gasket, air cathode and top plate. Because a through hole is opened on the middle plate and the anode gasket and cathode gasket, the two ends of the through hole are closed due to the clamping of the bottom plate 1 and the top plate 2, forming an electrolyte storage space (the electrolyte in the space can contact the anode and cathode), and the electrolyte storage space is connected to a pipeline, the inlet and outlet of the pipeline are connected to the liquid storage bottle, add about 500g of electrolyte to the liquid storage bottle, clamp the corresponding positive and negative poles with the test clip, insert the plug of the adapter into the 220V power socket, and the device can start running.

[0057] 2. Test methods

[0058] (1) Perform the following tests on the electrolyte:

[0059] The open circuit potential, electrochemical impedance spectroscopy, and polarization curve were tested using a first three-electrode system based on a GAMRY Reference 600+ electrochemical workstation (purchased from Gamry Electrochemical Import Equipment Company, USA). The electrochemical window was tested using a second electrode system based on a CHi760e electrochemical workstation (purchased from Shanghai Chenhua Instrument Co., Ltd.).

[0060] Open circuit potential test method (OCP) test method: Under the environmental conditions of 25°C, using the first three-electrode system, immerse the pretreated working electrode in the electrolyte, and test the open circuit potential (OCP) for 1200s.

[0061] Electrochemical impedance spectroscopy (EIS) test method: Under ambient conditions of 25°C, using the first three-electrode system, the pretreated working electrode was immersed in the electrolyte, and a sinusoidal perturbation signal with an amplitude of 5 mV was applied under steady-state OCP. The frequency sweep range was 10^5 Hz-1 Hz.

[0062] Polarization curve (PDP) test method: Under the environmental condition of 25°C, the first three-electrode system is used, and the steady-state OCP voltage is set from -250mV to +250mV at a scan rate of 1mV / s.

[0063] Electrochemical window test method: Under the environmental condition of 25°C, a second three-electrode system was used and linear sweep voltammetry (LSV) was used at a scan rate of 5 mV / s.

[0064] Hydrogen evolution test method: The amount of hydrogen evolved is measured using the water drainage method, which is then used to calculate the corresponding hydrogen evolution rate. The pretreated Al sample is immersed in the electrolyte to be tested for 30 minutes, and the drainage volume is recorded every 5 minutes.

[0065] (2) Perform the following tests on the full battery:

[0066] Constant current discharge curve test method: temperature is 25℃, at 20mA cm -2 The battery was discharged at a current density of 1 h to obtain its voltage-time curve.

[0067] Intermittent discharge curve test method: temperature is 25℃, at 20mA cm -2 Discharge at a current density of 1 h, and discharge at open circuit conditions for 20 min, for a total of four groups of intermittent discharges;

[0068] Long-term cycle discharge curve: temperature is 25℃, at 20mA cm -2 Discharge for 30 min at the current density and 30 min under open circuit conditions;

[0069] Step discharge curve test method: the temperature is 25℃, open circuit for 3min, then charge at 5, 10, 20, 40, 60, 80mA cm -2 A voltage-time curve of 10 minutes of discharge under step current density.

[0070] Linear sweep voltammetry (LSV) was used at a scan rate of 1 mV / s and a temperature of 25°C.

[0071] Example 1

[0072] 16 g of NaOH was weighed and dissolved in 100 mL of deionized water, and the solution was cooled to room temperature to obtain an alkaline solution. Subsequently, 0.0153 g of MPA was weighed and added to the alkaline solution, stirred and ultrasonicated to completely dissolve it, and cooled to room temperature to obtain an electrolyte solution (MPA concentration was 1 mM and NaOH concentration was 4 M).

[0073] Example 2

[0074] 16 g of NaOH was weighed and dissolved in 100 mL of deionized water, and the solution was cooled to room temperature to obtain an alkaline solution. Subsequently, 0.0765 g of MPA was weighed and added to the alkaline solution, stirred and ultrasonicated to completely dissolve it, and cooled to room temperature to obtain an electrolyte solution (MPA concentration of 5 mM, NaOH concentration of 4 M).

[0075] Example 3

[0076] 16 g of NaOH was weighed and dissolved in 100 mL of deionized water, and the solution was cooled to room temperature to obtain an alkaline solution. Subsequently, 0.1530 g of MPA was weighed and added to the alkaline solution, stirred and ultrasonicated to completely dissolve the solution, and cooled to room temperature to obtain an electrolyte solution (MPA concentration of 10 mM, NaOH concentration of 4 M).

[0077] Example 4

[0078] 16 g of NaOH was weighed and dissolved in 100 mL of deionized water, and the solution was cooled to room temperature to obtain an alkaline solution. Subsequently, 0.2295 g of MPA was weighed and added to the alkaline solution. The solution was stirred and ultrasonicated to completely dissolve the MPA, and the solution was cooled to room temperature to obtain an electrolyte solution (MPA concentration was 15 mM and NaOH concentration was 4 M).

[0079] Example 5

[0080] The same electrolyte (200 mL) was prepared according to the method of Example 3, placed in the liquid storage bottle of the full battery device, and connected to the assembled full battery device via a circulation pump at a flow rate of 5 mL / min.

[0081] Comparative Example 1

[0082] 16 g of NaOH was weighed and dissolved in 100 mL of deionized water, stirred thoroughly with ultrasound to completely dissolve it, and cooled to room temperature to obtain an electrolyte solution (NaOH concentration was 4 M).

[0083] Comparative Example 2

[0084] According to the method of Comparative Example 1, 200 mL of the same electrolyte was prepared, placed in the liquid storage bottle of the full battery device, and connected to the full battery device through a circulation pump with a flow rate of 5 mL / min.

[0085] Test Example 1

[0086] The electrolytes prepared in Examples 1-4 and Comparative Example 1 were subjected to electrochemical tests using the first three-electrode system, and their open circuit potential (OCP), electrochemical impedance spectrum (EIS), and polarization curve (PDP) were measured respectively. The data were fitted using ZSimpWin3.60 software. The impedance spectrum fitting diagrams of each sample are shown in FIG. Figure 1 、 2 The fitting results are shown in Table 1.

[0087] In Table 1, C represents the corresponding concentration R of MPA s is the solution resistance in the high frequency region, R ct,1 is the charge transfer resistance in the high frequency region, CPE1 is the constant phase component in the high frequency region, L is the inductance in the intermediate frequency region, R is the inductor resistance, and R ct,2 is the charge transfer resistance in the low-frequency region and CPE2 is the constant phase component in the low-frequency region, R T is the total c resistance of the system, is the polarization resistance, and η is the corrosion inhibition efficiency.

[0088] Table 1

[0089]

[0090]

[0091] The Tafel curve fitting results obtained using the polarization curves of each sample are shown in Table 2.

[0092] Table 2

[0093]

[0094] In Table 2, C represents the corresponding concentration of MPA, E corr is the potential corresponding to the self-corrosion current (icorr), which reflects the corrosion tendency of the material in its natural state, and β c is the cathode Tafel slope, β a is the anodic Tafel slope, calculated by the Tafel extrapolation method.

[0095] Combining Table 1 and Table 2 and Figure 1-4 It can be seen that as the MPA concentration increases, the impedance spectrum radius increases significantly, the polarization resistance increases, and the corrosion current density decreases. Among them, Example 3 shows the best corrosion inhibition performance, with a corrosion inhibition efficiency of 40.8%.

[0096] Test Example 2

[0097] The electrolytes prepared in Examples 1-4 and Comparative Example 1 were used to perform electrochemical window tests using the second three-electrode body.

[0098] The results are as follows Figure 4 As shown in Figure 3, the improvement of electrolyte stability by MPA is further revealed, which is manifested as a significant expansion of the electrochemical window.

[0099] Test Example 3

[0100] The electrolytes prepared in Examples 1-4 and Comparative Example 1 were subjected to hydrogen evolution tests. The pretreated Al samples were immersed in the corresponding electrolytes for 30 minutes, and the discharge volume was recorded every 5 minutes.

[0101] The results are as follows Figure 5 As shown in the figure, it can be seen that the volume of hydrogen evolution in the MPA-containing system is significantly reduced, and the reduction amount is positively correlated with the concentration of MPA.

[0102] The hydrogen volume obtained in this test was used to further calculate the hydrogen evolution rate and inhibition efficiency, where hydrogen evolution rate = hydrogen evolution volume / (reaction area × reaction time), inhibition efficiency = (hydrogen evolution rate of experimental group - hydrogen evolution rate of blank group) / hydrogen evolution rate of blank group × 100% (wherein the blank group refers to Comparative Example 1). The results are as follows: Figure 6 As shown in the figure, it can be seen that as the MPA concentration increases to 10 mM, the hydrogen evolution rate shows a downward trend, and the highest inhibition efficiency can reach 41.7%.

[0103] Test Example 4

[0104] At 20 mA cm -2 The batteries were discharged at a current density of 1 h, and the constant current discharge curve, intermittent discharge curve, and long-term cycle discharge curve of Example 5 and Comparative Example 2 were tested respectively.

[0105] At 5, 10, 20, 40, 60 and 80 mA cm -2 The step discharge curves of Example 5 and Comparative Example 2 were tested respectively at a current density of 10 min.

[0106] Linear sweep voltammetry (LSV, 2 mV S -1 ) Obtain the polarization curves and power density curves of Example 5 and Comparative Example 2.

[0107] The constant current discharge curve results are as follows Figure 7 As shown, from Figure 7 It can be seen that after adding 10mM MPA, the battery capacity density increased to 1379.3mA·h·g -1 , the energy density reaches 1601.8Wh·kg -1 , aluminum anode utilization rate increased to 46.3% ( Among them, U a is the anode utilization efficiency (%), I is the discharge current (mA), t is the discharge time (h), Δm is the weight loss of Al after discharge, and F is the Faraday constant (C / mol).

[0108] Polarization curves and power density curves are shown in Figure 2. Figure 8 As shown in the figure, it can be seen that the battery power density of Example 5 reaches 63.56mW·cm -2 , compared with Comparative Example 2, it is increased by 21.7%.

[0109] Intermittent discharge curve Figure 9As shown in the figure, it can be seen that compared with Comparative Example 2, Example 5 has a higher and more stable discharge voltage, and also has better discharge performance during the 6-hour continuous intermittent discharge process.

[0110] Step discharge curve Figure 10 As shown, from Figure 10 It can be seen that when the current density is increased from 5 mA cm -2 Increase to 80mAcm -2 When the voltage of Comparative Example 2 drops sharply from 1.2V to 0.2V in 1.2 hours, Example 5 can maintain a higher output voltage during continuous discharge under the same conditions, showing better discharge performance.

[0111] from Figure 11 It can be seen that the long cycle stable discharge time of the battery of Example 5 is 44 hours, while the long cycle stable discharge time of the battery of Comparative Example 2 is only 26 hours, after which a potential drop occurs (complete penetration failure of the anode). Compared with Comparative Example 2, the discharge time of the battery of Example 5 is extended by 69%, which is directly related to the corrosion inhibition effect of MPA.

[0112] Test Example 5

[0113] Pretreated Al samples were taken and immersed in the electrolytes prepared in Example 3 and Comparative Example 1 for 1 hour, and then the samples were subjected to SEM test (ZEISS EVO18), CLSM test (CLSM, OLS 5000) and water contact angle test (CA, SL150E, θ / 2 method). The results are shown in Figure 2. Figure 12-17 shown.

[0114] analyze Figure 12 and 13 It can be seen that the aluminum sample after being immersed in the electrolyte prepared in Example 3 only exhibits superficial etching, confirming the effective adsorption of MPA molecules on the Al surface.

[0115] analyze Figure 14 and 15 It was found that the surface roughness of the aluminum sample immersed in the electrolyte prepared in Comparative Example 1 was 168.9 nm, while the surface roughness of the aluminum sample immersed in the electrolyte prepared in Example 3 was significantly reduced to 49.7 nm, and its surface became smoother.

[0116] Further analysis Figure 16-17 It is shown that compared with Comparative Example 1, the MPA treatment contained in Example 3 increases the contact angle of the aluminum sample from 41° to 55°. This hydrophobic transformation is due to the formation of an adsorption layer by MPA molecules on the electrode surface, which effectively blocks the direct contact between the electrolyte and the metal substrate.

[0117] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention may be subjected to various simple modifications, including combining the specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. Application of a pyridine derivative in an aluminum-air battery electrolyte, characterized in that: The pyridine derivative has a pyridine ring, a thiol group and a carboxylic acid group, and the pyridine derivative serves as an aluminum corrosion inhibitor.

2. The use according to claim 1, wherein The pyridine derivatives include 2-mercapto-3-pyridinecarboxylic acid.

3. An electrolyte, characterized in that The electrolyte includes a solute, a solvent and an additive, wherein the solute includes a strong base, and the additive includes a pyridine derivative having a pyridine ring, a thiol group and a carboxylic acid group.

4. The electrolyte according to claim 3, wherein The pyridine derivatives include 2-mercapto-3-pyridinecarboxylic acid.

5. The electrolyte according to claim 3 or 4, wherein Based on the total amount of the electrolyte, the concentration of the pyridine derivative is 1-15 mM, preferably 8-10 mM.

6. The electrolyte according to any one of claims 3 to 5, wherein The strong base is sodium hydroxide and / or potassium hydroxide.

7. The electrolyte according to claim 6, wherein Based on the total amount of the electrolyte, the concentration of the strong base is 3-5M, preferably 4M.

8. The electrolyte according to claim 7, wherein The solvent is deionized water.

9. The electrolyte according to claim 7, wherein The electrolyte consists of a solute, a solvent and an additive, wherein the solute is sodium hydroxide, the additive is 2-mercapto-3-pyridinecarboxylic acid, and the solvent is deionized water. Based on the total amount of the electrolyte, the concentration of the 2-mercapto-3-pyridinecarboxylic acid is 8-10 mM, and the concentration of the sodium hydroxide is 3-5 M, preferably 4 M.

10. An aluminum-air battery comprising the electrolyte according to any one of claims 2 to 9.

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