Aluminum-sulfur battery electrolyte for promoting high-valence oxidation of sulfur and aluminum-sulfur battery

Abstract

The invention discloses an aluminum-sulfur battery electrolyte for promoting high-valence oxidation of sulfur. The aluminum-sulfur battery electrolyte comprises Lewis acidic electrolyte salt; an organic ligand, wherein the organic ligand and the Lewis acidic electrolyte salt form a room temperature ionic liquid or an ionic-like liquid; a chloride ion concentration regulating agent; the chloride ion concentration regulating agent is used for promoting elemental sulfur of the positive electrode of the battery to be subjected to electrochemical oxidation in the charging process of the aluminum-sulfur secondary battery so as to generate a sulfur oxidation product with the valence state of + 2. Meanwhile, the invention provides the aluminum-sulfur battery, high-valence electrochemical oxidation of the positive sulfur element in the charging process is remarkably promoted, and the specific discharge capacity is greatly improved, so that the aluminum-sulfur battery with high energy density is constructed.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to an aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in high valence states and the aluminum-sulfur battery thereof. Background Technology

[0002] Electrochemical energy storage devices play a crucial role in portable electronic devices, electric vehicles, and energy storage power stations. In recent years, aluminum has been considered an ideal anode material for constructing novel rechargeable batteries due to its extremely high theoretical volumetric capacity (8046 mAh / cm3), high theoretical mass capacity (2978 mAh / g), abundant reserves in the Earth's crust, and low cost.

[0003] However, the practical application of aluminum-ion batteries is limited by the lack of high-performance cathode materials. Traditional cathode materials such as graphite, oxides, and sulfides generally have low specific capacities, which limits the overall energy density of the battery. Elemental sulfur (S) has a theoretical specific capacity as high as 1672 mAh / g and low cost advantages, and is considered one of the most promising cathode materials for aluminum-ion batteries.

[0004] Despite their immense potential, the development of traditional aluminum-sulfur batteries faces a fundamental bottleneck: an excessively low discharge voltage plateau. The electrochemical reaction process in these batteries is similar to that of lithium-sulfur batteries, involving a reversible reaction between elemental sulfur (S8) and its sulfide (S2-), i.e., the electrochemical reduction mechanism of sulfur. The theoretical discharge voltage plateau for this reaction is only about 1.25V (vs. Al / Al3+). This low voltage severely limits the energy density of Al-S batteries. To improve the voltage plateau of aluminum-sulfur batteries, researchers have tried various strategies, including porous carbon frameworks, the introduction of catalysts, and electrolyte modification. However, these strategies have only increased the voltage plateau to 0.7V to 1.0V, failing to break through the theoretical upper limit of 1.25V.

[0005] In recent years, a new type of aluminum-sulfur battery has emerged, fundamentally altering its mechanism. In this system (e.g., using AlCl3 / urea or AlCl3 / acetamide electrolytes), elemental sulfur is oxidized to positively charged sulfur compounds during charging. These oxidation products have been confirmed to be chlorine-containing sulfides, such as AlSCl7 or S2Cl2, SCl2. This oxidation mechanism fundamentally increases the battery's discharge voltage plateau (greater than 1.8V). The valence state of sulfur is closely related to the theoretical voltage: when the oxidation product is S2Cl2 (sulfur at +1), the theoretical voltage is 1.8V, and the theoretical capacity is 836mAh / g; while when the oxidation product is SCl2 (sulfur at +2), the theoretical voltage reaches as high as 2.0V, and the theoretical capacity is 1672mAh / g.

[0006] However, this novel oxidation mechanism of Al-S batteries still faces its unique challenges: the electrochemical oxidation valence state of sulfur is relatively low. Among the products reported so far, +1 valence S2Cl2 often dominates, resulting in an actual voltage plateau (~1.8V) that is still lower than the theoretical value (e.g., 2.03V for S(+2) or 2.10V for S(+4)). Therefore, how to effectively control the valence state of sulfur, prompting elemental sulfur to be oxidized to a higher valence state (e.g., +2, +3, or +4) during charging, is a key technical problem for further improving the energy density of Al-S batteries. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide an aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in a high valence state. This invention significantly promotes the electrochemical oxidation of elemental sulfur in the cathode to a high valence state (+2 valence) during charging, greatly improving the discharge specific capacity, thereby constructing a high energy density aluminum-sulfur battery.

[0008] To achieve the above objectives, the present invention provides an aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in its high valence state, comprising:

[0009] Lewis acidic electrolyte salts;

[0010] An organic ligand that forms a room-temperature ionic liquid or ionic liquid-like substance with the Lewis acidic electrolyte salt;

[0011] Chloride ion concentration regulator; the chloride ion concentration regulator is used to promote the electrochemical oxidation of elemental sulfur in the positive electrode of the aluminum-sulfur secondary battery during the charging process, generating sulfur oxide products with a +2 valence state.

[0012] Furthermore, the Lewis acidic electrolyte salt is AlCl3, and the organic ligand is acetamide, propionamide, butyramide, urea, 1-ethyl-3-methylimidazolium chloride, or triethylamine hydrochloride, and the molar ratio of the Lewis acidic electrolyte salt to the organic ligand is 1.1:1 to 1.7:1.

[0013] Furthermore, the chloride ion concentration regulator is an alkali metal chloride.

[0014] Furthermore, the alkali metal chloride is one or a combination of two or more of lithium chloride, sodium chloride, and potassium chloride.

[0015] Furthermore, the concentration of the chloride ion concentration regulator in the electrolyte is 0.01 mol / L to 1.0 mol / L.

[0016] The present invention also provides an aluminum-sulfur battery, comprising a metallic aluminum negative electrode, a sulfur-containing positive electrode, and the above-mentioned aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in high valence states.

[0017] Furthermore, the sulfur-containing cathode comprises elemental sulfur and a porous conductive framework.

[0018] Furthermore, the porous conductive framework is composed of ordered mesoporous carbon (CMK3).

[0019] Furthermore, the aluminum-sulfur secondary battery exhibits a discharge voltage of not less than 1.8V (vs. Al / Al). 3+ The average discharge voltage plateau.

[0020] Furthermore, the discharge voltage of the average discharge voltage plateau is 2.0V (vs. Al / Al). 3+ ).

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The inventors discovered that in room-temperature ionic liquid systems like AlCl3 / acetamide, the electrochemical oxidation state of sulfur is highly sensitive to the activity (pCl) of Cl- in the electrolyte. This invention achieves precise control of the electrolyte's pCl value by introducing an independent chloride ion concentration regulator (such as NaCl), rather than adjusting the amount of AlCl3.

[0023] This regulation of Cl- activity can effectively reduce the Gibbs free energy of high-valence sulfur chlorides (such as SCl2 (S(+2) valence) or SCl3+ (S(+3) valence)), thereby thermodynamically promoting the transformation of sulfur to higher oxidation states during charging.

[0024] The comparative battery without the added regulator had a discharge voltage plateau mainly below 1.5V; however, after adding the chloride ion concentration regulator, the discharge voltage plateau was significantly improved, and the discharge specific capacity increased substantially. This invention successfully raised the electrochemical oxidation valence state of sulfur to a higher level (approaching or reaching the theoretical plateau of 2.03V for S(+2) valence).

[0025] Furthermore, theoretical calculations show that sulfur chlorides with S(+5) and S(+6) valences exhibit poor stability, while products with S(+2) valences (such as SCl2) and S(+3) valences (such as SCl3+) demonstrate better stability. This invention achieves effective control over the S(+2) / S(+3) valence range by adjusting the Cl- concentration, thus achieving an ideal balance between increasing energy density and ensuring product stability. Attached Figure Description

[0026] To more clearly illustrate the technology in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 The discharge curve of the aluminum-sulfur battery with 0.1 mol / L NaCl added to the electrolyte in Example 1 of this invention is shown.

[0028] Figure 2 The discharge curve of the aluminum-sulfur battery with 0.1 mol / L LiCl added to the electrolyte in Example 2 of this invention is shown.

[0029] Figure 3 The discharge curve of the aluminum-sulfur battery with 0.5 mol / L NaCl added to the electrolyte in Example 3 of this invention is shown.

[0030] Figure 4 This is the discharge curve of an aluminum-sulfur battery with 1 mol / L NaCl added to the electrolyte in Example 4 of this invention;

[0031] Figure 5 The discharge curve of an aluminum-sulfur battery with an anhydrous aluminum trichloride and acetamide molar ratio of 1.1:1 and 0.1 mol / L NaCl added to the electrolyte in Example 5 of this invention is shown.

[0032] Figure 6 The discharge curve of an aluminum-sulfur battery with an anhydrous aluminum trichloride and acetamide molar ratio of 1.7:1 and 0.1 mol / L NaCl added in the electrolyte of Example 5 of this invention is shown.

[0033] Figure 7 The discharge curve of the aluminum-sulfur battery of Comparative Example 1 (without additives) of this invention is shown.

[0034] Figure 8 This is the XPS S2p plot of the charged electrode of the aluminum-sulfur battery with 0.1 mol / L NaCl added to the electrolyte of this invention. Detailed Implementation

[0035] The technology of this embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiment is one embodiment of the present invention, and not all embodiments thereof. Based on this embodiment of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] Furthermore, if the embodiments of the present invention involve descriptions such as "first" or "second", such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0038] This invention provides an aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in its higher oxidation state, comprising:

[0039] Lewis acidic electrolyte salts, organic ligands, and chloride ion concentration modifiers.

[0040] Preferably, the Lewis acidic electrolyte salt of the present invention is AlCl3.

[0041] The organic ligand is an amide compound such as acetamide, propionamide, butyramide, or urea, or it can be 1-ethyl-3-methylimidazolium chloride or triethylamine hydrochloride, etc. The Lewis acid electrolyte salt and the organic ligand are mixed in a certain molar ratio to form an ionic liquid or ionic liquid-like solution (eutectic salt electrolyte) at room temperature. For example, AlCl3 and acetamide are mixed to form an AlCl3 / acetamide eutectic salt electrolyte at room temperature. Preferably, the molar ratio of Lewis acid electrolyte salt to organic ligand is 1.1:1 to 1.7:1. When the molar ratio is lower than 1.1:1, the Lewis acidity in the electrolyte is insufficient, making it difficult to effectively promote the oxidation of sulfur in its higher valence state. When the molar ratio is higher than 1.7:1, crystallization is likely to occur in the system, affecting the stability and ionic conductivity of the electrolyte.

[0042] The chloride ion concentration regulator is used to promote the electrochemical oxidation of elemental sulfur at the positive electrode of the aluminum-sulfur secondary battery during the charging process, generating sulfur oxide products with a +2 oxidation state.

[0043] Specifically, the chloride ion concentration regulator is added independently of the basic electrolyte components. After the Lewis acidic electrolyte salt and organic ligands are mixed to form a room-temperature ionic liquid or ionic liquid-like substance, the chloride ion concentration regulator is added to regulate the activity of free chloride ions (Cl-) in the electrolyte (i.e., pCl value).

[0044] Preferably, the chloride ion concentration regulator is an alkali metal chloride. More preferably, the alkali metal chloride is selected from one or more combinations of lithium chloride (LiCl), sodium chloride (NaCl), and potassium chloride (KCl).

[0045] The concentration of the chloride ion concentration regulator added to the electrolyte is preferably from 0.01 mol / L to 1.0 mol / L, more preferably from 0.05 mol / L to 0.5 mol / L, and even more preferably 0.1 mol / L.

[0046] The present invention also provides an aluminum-sulfur battery, comprising a metallic aluminum negative electrode, a sulfur-containing positive electrode, and the above-mentioned aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in high valence states.

[0047] Preferably, in the sulfur-containing cathode, since the electrochemical oxidation products of sulfur (such as SCl2) may be in liquid state, the sulfur-containing cathode of this embodiment preferably includes elemental sulfur and a porous conductive framework composed of ordered mesoporous carbon, which is used to anchor sulfur and sulfur oxidation products.

[0048] The aluminum-sulfur secondary battery of this embodiment has an average discharge voltage plateau of not less than 1.8V (vs. Al / Al3+) during discharge. Preferably, the average discharge voltage plateau of the aluminum-sulfur secondary battery of this embodiment is 2.0V (vs. Al / Al3+), which significantly improves cycle stability.

[0049] Example 1

[0050] This invention provides an aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in its higher oxidation states, comprising: a Lewis acidic electrolyte salt, wherein in this embodiment, the Lewis acidic electrolyte salt is AlCl3.

[0051] The organic ligand, in this embodiment, is acetamide;

[0052] And a chloride ion concentration regulator, in this embodiment the chloride ion concentration regulator is sodium chloride;

[0053] The specific preparation method is as follows:

[0054] (1) Preparation of basic electrolyte: Anhydrous aluminum trichloride (AlCl3) and acetamide (CH3CONH2) were mixed in a molar ratio of 1.3:1 in a glove box filled with high-purity argon. Then the mixture was magnetically stirred at room temperature for 2 hours until a clear and transparent AlCl3 / acetamide ionic liquid (eutectic salt) electrolyte was formed;

[0055] (2) In the glove box, take the basic electrolyte prepared in step (1), add analytical grade sodium chloride (NaCl) powder to it, so that the final concentration of NaCl in the electrolyte is 0.1 mol / L, stir magnetically for 4 hours to ensure that NaCl is completely dissolved, and obtain the regulated electrolyte of the present invention.

[0056] Based on the regulated electrolyte of the present invention, an aluminum-sulfur secondary battery is also provided, which includes a metallic aluminum anode, a sulfur-containing cathode, and the above-mentioned regulated electrolyte.

[0057] The preparation method of this aluminum-sulfur secondary battery is as follows:

[0058] (3) Preparation of positive electrode: Ordered mesoporous carbon (CMK3) is used as carrier. CMK3 and sublimed sulfur are mixed and ground evenly in a mortar at a mass ratio of 40:60 (i.e., sulfur loading rate of 60%). The mixture is placed in a tube furnace and heated at 155°C for 12 hours under an argon atmosphere to melt the sulfur and allow it to fully penetrate into the pores of CMK3. After cooling, S@CMK3 composite positive electrode material is obtained.

[0059] S@CMK3 composite material, conductive carbon black (SuperP), and binder (PVDF) were mixed in N-methylpyrrolidone (NMP) solvent at a mass ratio of 8:1:1 to form a slurry. The slurry was uniformly coated onto an aluminum foil current collector, dried in a vacuum oven at 60°C for 12 hours, and then cut into sheets to obtain sulfur cathode sheets.

[0060] Battery assembly: In the glove box, a high-purity aluminum sheet (Al) is used as the negative electrode, the S@CMK3 sulfur positive electrode obtained in step (3) is used as the positive electrode, the glass fiber membrane (WhatmanGF / D) is used as the separator, and the basic electrolyte prepared in step (2) is used as the electrolyte to assemble a CR2032 coin cell.

[0061] Electrochemical testing: At room temperature, the battery was subjected to constant current charge-discharge testing using the LAND battery testing system, with a charging cutoff voltage of 2.4V and a discharging cutoff voltage of 0.5V.

[0062] Results Analysis: The test results are as follows: Figure 1 The curve for "addition of 0.1 mol / L sodium chloride" is shown in the figure. Compared with the reference battery of Comparative Example 1, the first discharge curve of the battery in this embodiment shows a significant difference:

[0063] 1. Increased voltage plateau: The discharge voltage plateau is significantly increased, with a relatively long discharge plateau appearing at approximately 2.0V.

[0064] 2. Increased specific capacity: The specific capacity of the first discharge cycle is significantly increased to approximately 500 mAh / g.

[0065] Conclusion: Experimental data clearly demonstrate that the addition of 0.1 mol / L NaCl, as a chloride ion concentration regulator, successfully modulates the electrochemical oxidation reaction pathway of sulfur, causing it to transition to a higher oxidation state (close to the theoretical plateau of 2.03V for S(+2) oxidation state), thereby significantly improving the battery's discharge voltage and energy density.

[0066] Example 2

[0067] The difference between this embodiment and Example 1 is that in the electrolyte preparation, the 0.1 mol / L NaCl in Example 1 is replaced with 0.1 mol / L anhydrous lithium chloride (LiCl), while the remaining steps (basic electrolyte preparation, positive electrode preparation, and battery assembly) are the same as in Example 1.

[0068] The battery obtained in this embodiment was tested under the same charging and discharging conditions as in Embodiment 1 (charging cutoff 2.4V, discharging cutoff 0.5V).

[0069] Result: As Figure 2 As shown, electrochemical tests revealed that the battery obtained in this embodiment also exhibited a significantly higher discharge plateau (approximately 1.9 V) and improved specific capacity compared to Comparative Example 1. This result demonstrates that LiCl is also effective as a chloride ion concentration regulator, and the technical solution of this invention is not limited to NaCl.

[0070] Example 3

[0071] The difference between this embodiment and Example 1 is that in the preparation of the electrolyte, the 0.1 mol / L NaCl in Example 1 is replaced with 0.5 mol / L NaCl, and the remaining steps are the same as in Example 1.

[0072] The battery obtained in this embodiment was tested under the same charging and discharging conditions as in Embodiment 1 (charging cutoff 2.4V, discharging cutoff 0.5V).

[0073] Result: As Figure 3 As shown, electrochemical tests revealed that the battery obtained in this embodiment exhibited similar high electrochemical performance (high voltage plateau and high capacity) to that in Example 1, demonstrating that the technical solution of the present invention has a regulatory effect over a wide concentration range of 0.01-1.0 mol / L.

[0074] Example 4

[0075] The difference between this embodiment and Example 1 is that in the preparation of the electrolyte, the 0.1 mol / L NaCl in Example 1 is replaced with 1.0 mol / L NaCl, and the remaining steps are the same as in Example 1.

[0076] The battery obtained in this embodiment was tested under the same charging and discharging conditions as in Embodiment 1 (charging cutoff 2.4V, discharging cutoff 0.5V).

[0077] Result: As Figure 4As shown, electrochemical tests revealed that the battery obtained in this embodiment exhibited similar high electrochemical performance (high voltage plateau and high capacity) to that in Example 1, demonstrating that the technical solution of the present invention has a regulatory effect over a wide concentration range of 0.01-1.0 mol / L.

[0078] Example 5

[0079] The difference between this embodiment and Example 1 is that in the preparation of the electrolyte, the molar ratio of anhydrous aluminum trichloride and acetamide in Example 1 is replaced with 1.1:1 instead of 1.3:1. All other steps are the same as in Example 1.

[0080] The battery obtained in this embodiment was tested under the same charging and discharging conditions as in Embodiment 1 (charging cutoff 2.4V, discharging cutoff 0.5V).

[0081] Result: As Figure 5 As shown, electrochemical tests revealed that the battery obtained in this embodiment exhibited similar high electrochemical performance (high voltage plateau and high capacity) to that of Example 1, proving that the technical solution of the present invention works when the molar ratio of anhydrous aluminum trichloride and acetamide is 1.1:1 under the control of 0.1 mol / L. This result proves that changing the molar ratio of anhydrous aluminum trichloride and acetamide is also effective, and the technical solution of the present invention is not limited to a ratio of 1.3:1.

[0082] Example 6

[0083] The difference between this embodiment and Example 1 is that in the preparation of the electrolyte, the molar ratio of anhydrous aluminum trichloride and acetamide in Example 1 is replaced with 1.7:1 instead of 1.3:1, while the other steps are the same as in Example 1.

[0084] The battery obtained in this embodiment was tested under the same charging and discharging conditions as in Embodiment 1 (charging cutoff 2.4V, discharging cutoff 0.5V).

[0085] Result: As Figure 6 As shown, electrochemical testing revealed that the battery obtained in this embodiment exhibited similar high electrochemical performance (high voltage plateau and high capacity) to that of Example 1, proving that the technical solution of the present invention works when the molar ratio of anhydrous aluminum trichloride to acetamide is 1.7:1 under the control of 0.1 mol / L. This result demonstrates that changing the molar ratio of anhydrous aluminum trichloride to acetamide is also effective, and the technical solution of the present invention is not limited to a ratio of 1.3:1.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that no chloride is added in the preparation of the electrolyte, only the basic electrolyte prepared in step (1) is used, and the remaining steps are the same as in Example 1.

[0088] The battery obtained in this comparative example was tested under the same charge and discharge conditions as in Example 1 (charge cutoff 2.4V, discharge cutoff 0.5V).

[0089] Results: The initial discharge curve of the comparative battery is as follows: Figure 7 The curve shown is for the "no sodium chloride added" scenario. Its discharge voltage plateau is mainly below 1.95V, the discharge curve is sloping, and the initial discharge specific capacity is approximately 350 mAh / g. This indicates that in the basic electrolyte, the oxidation reaction of sulfur has poor reversibility or a low oxidation state.

[0090] Mechanism verification - XPS characterization

[0091] Finally, to verify the regulatory mechanism of the present invention (i.e., promoting the generation of high-valence sulfur), the battery of Example 1 (with added NaCl) was charged to 2.4V and then stopped, and the battery was disassembled in a glove box.

[0092] XPS Analysis: The positive electrode was removed, and the surface residual electrolyte was quickly cleaned with solvent before being transferred to an X-ray photoelectron spectroscopy (XPS) instrument for testing.

[0093] The results are as follows Figure 8 As shown: After fitting, the S 2p spectrum of the positive electrode in Example 1 mainly shows the signal peaks from S(+2) valence to S(+4) valence.

[0094] Conclusion: The XPS characterization results above conclusively prove the core mechanism of the present invention: the addition of NaCl as a chloride ion concentration regulator successfully promoted the formation of high-valence (+2) sulfur chloride oxidation products through the electrochemical oxidation pathway of sulfur. This is completely consistent with the 2.0V high-voltage plateau observed in Example 1. Therefore, the present invention achieves effective control towards the S(+2) / S(+3) valence range by regulating the Cl- concentration, thereby achieving an ideal balance between improving energy density and ensuring product stability.

[0095] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aluminum-sulfur battery electrolyte that promotes the oxidation of sulfur in its high valence state, characterized in that, include: Lewis acidic electrolyte salts; An organic ligand that forms a room-temperature ionic liquid or ionic liquid-like substance with the Lewis acidic electrolyte salt; Chloride ion concentration regulator; the chloride ion concentration regulator is used to promote the electrochemical oxidation of elemental sulfur in the positive electrode of the aluminum-sulfur secondary battery during the charging process, generating sulfur oxide products with a +2 valence state.

2. The aluminum-sulfur battery electrolyte for promoting the oxidation of sulfur in its high valence state according to claim 1, characterized in that, The Lewis acidic electrolyte salt is AlCl3, and the organic ligand is acetamide, propionamide, butyramide, urea, 1-ethyl-3-methylimidazolium chloride, or triethylamine hydrochloride. The molar ratio of the Lewis acidic electrolyte salt to the organic ligand is 1.1:1 to 1.7:

1.

3. The aluminum-sulfur battery electrolyte for promoting the oxidation of sulfur in its high valence state according to claim 1, characterized in that, The chloride ion concentration regulator is an alkali metal chloride.

4. The aluminum-sulfur battery electrolyte for promoting the oxidation of sulfur in its high valence state according to claim 3, characterized in that, The alkali metal chloride is one or a combination of two or more of lithium chloride, sodium chloride, and potassium chloride.

5. An aluminum-sulfur battery electrolyte for promoting the oxidation of sulfur in its high valence state according to any one of claims 1-4, characterized in that, The concentration of the chloride ion concentration regulator in the electrolyte is 0.01 mol / L to 1.0 mol / L.

6. An aluminum-sulfur battery, characterized in that, It includes a metallic aluminum anode, a sulfur-containing cathode, and an aluminum-sulfur battery electrolyte according to any one of claims 1 to 5 that promotes the oxidation of sulfur in a high valence state.

7. An aluminum-sulfur battery according to claim 6, characterized in that, The sulfur-containing cathode comprises elemental sulfur and a porous conductive framework.

8. An aluminum-sulfur battery according to claim 7, characterized in that, The porous conductive framework is composed of ordered mesoporous carbon.

9. An aluminum-sulfur battery according to claim 6, characterized in that, The aluminum-sulfur secondary battery has an average discharge voltage plateau of not less than 1.8V during discharge.

10. An aluminum-sulfur battery according to claim 9, characterized in that, The discharge voltage of the average discharge voltage platform is 2.0V.

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