Alkaline ionic liquid electrolytes, methods of preparation and use in aluminum primary batteries

Abstract

This invention belongs to the field of aluminum-based galvanic cell technology and discloses an alkaline ionic liquid electrolyte, which is composed of AlCl3 and 1-ethyl-3-methylimidazolium chloride and Cl from an alkali metal chloride salt. ‑ The reaction proceeds to obtain the product through a coordination reaction; the general formula of the starting material is A. a E b X c A is aluminum chloride, E is 1-ethyl-3-methylimidazolium chloride, and X is an alkali metal chloride; 0.4 ≤ a ≤ 0.8, 0.9 ≤ b ≤ 1, 0 ≤ c ≤ 0.1. This invention is the first to propose using an alkaline ionic liquid electrolyte to replace the traditional acidic ionic liquid electrolyte, changing the composition of the active ion / molecular groups and promoting the release of free Cl... ‑ The stable presence of alkali metal cations can significantly improve the electrochemical performance of aluminum-carbon fluoride and aluminum-sulfur primary batteries, exhibiting higher discharge specific capacity, discharge voltage plateau and excellent rate performance, effectively balancing advantages such as high energy density, excellent safety performance, low cost and wide operating temperature range.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-based primary battery technology, specifically relating to an alkaline ionic liquid electrolyte, its preparation method, and its application in aluminum primary batteries. Background Technology

[0002] Fluorinated carbon materials, due to their high theoretical specific capacity, excellent chemical stability, and thermal stability, enable lithium-fluorinated carbon primary batteries (primary batteries) to achieve high energy density and low self-discharge rates, making them a stable and reliable power source option. Similarly, sulfur, as a cathode material, offers advantages such as extremely high theoretical specific capacity (~1675 mAh / g) and low cost, making lithium-sulfur primary batteries a promising candidate for high-energy-density applications. Thanks to these properties, lithium-fluorinated carbon and lithium-sulfur primary batteries demonstrate continued and significant application value in specific fields with stringent requirements for energy density, reliability, and long-term stability.

[0003] However, the high cost and limited reserves of lithium restrict its widespread adoption in large-scale energy storage applications. In contrast, aluminum batteries, with their low-cost aluminum anodes, abundant crustal reserves, and high theoretical volumetric capacity, are considered a promising next-generation energy storage system. Aluminum-carbon fluoride and aluminum-sulfur primary batteries combine the advantages of aluminum anodes with carbon fluoride or sulfur cathodes, and are expected to overcome the limitations of lithium-based batteries in terms of cost and resource reserves, providing new solutions for high-performance energy storage systems.

[0004] In aluminum-carbon fluoride and aluminum-sulfur galvanic cell systems, the electrolyte is crucial for achieving high performance. As the medium for electrochemical reactions and the ion transport carrier, the electrolyte not only directly participates in the redox reactions at the cathode and anode but also determines the overall electrochemical performance of the battery system. 3+ Ions, with their small ionic radii and high charge densities, involve complex three-electron transfer processes, placing higher demands on the ionic conductivity and reaction kinetics of electrolytes. Existing aluminum batteries typically use an acidic ionic liquid prepared from aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) as the electrolyte. Under acidic conditions, the main anion in the electrolyte is AlCl4. - and Al2Cl7 - During the secondary battery charging process, Al2Cl7 - The presence of ion clusters is crucial to ensuring the effective deposition of aluminum ions at the negative electrode; therefore, existing research typically uses acidic ionic liquid electrolytes.

[0005] However, when preparing aluminum-carbon fluoride primary batteries using acidic electrolytes, the conversion reaction kinetics are slow, facing significant kinetic limitations. This results in a low actual discharge voltage plateau (0.1-0.2 V), insufficient specific capacity (<100 mAh / g, far below the theoretical capacity of fluoride), and poor rate performance, making it difficult to meet practical application requirements. Similarly, aluminum-sulfur primary batteries in acidic ionic liquid electrolyte systems exhibit a low discharge voltage plateau (0.4-0.5 V) and poor rate performance due to the limited kinetics of the sulfur cathode reaction, restricting their effectiveness in practical applications.

[0006] Further development of aluminum-ion electrolytes with excellent reaction kinetics to promote high specific capacity and superior rate performance in aluminum-carbon fluoride and aluminum-sulfur primary batteries is a key prerequisite for constructing high energy density and high power density aluminum-based primary batteries. Summary of the Invention

[0007] To address the problems and shortcomings of existing technologies, this invention proposes an alkaline ionic liquid electrolyte and novel aluminum-based primary battery systems (aluminum-carbon fluoride and aluminum-sulfur primary battery systems) based on this electrolyte. By replacing the traditional acidic ionic liquid electrolyte with an alkaline ionic liquid electrolyte and introducing alkali metal cations into the electrolyte, the electrochemical performance of the aluminum-based primary battery can be significantly improved, exhibiting higher discharge specific capacity, discharge voltage plateau, and excellent rate performance. It can also effectively balance the advantages of excellent safety performance, low cost, and wide operating temperature range.

[0008] One objective of this invention is to provide an alkaline ionic liquid electrolyte that optimizes the solvation structure of the electrolyte, alters the composition of active ions / molecular groups, and promotes the release of free Cl-. - The stable presence of ions and alkali metal cations significantly enhances and optimizes the electrochemical reaction kinetics of aluminum-based galvanic cell systems.

[0009] The second objective of this invention is to provide a method for preparing an alkaline ionic liquid electrolyte, which has the advantages of simple operation, short process flow, low preparation cost, and suitability for mass production.

[0010] The third objective of this invention is to provide a novel aluminum-carbon fluoride primary battery with high specific energy, which utilizes the above-mentioned alkaline ionic liquid electrolyte to effectively accelerate electrochemical reaction kinetics, thereby achieving excellent characteristics such as high discharge specific capacity, excellent rate performance, and a wide operating temperature range.

[0011] The fourth objective of this invention is to provide an aluminum-sulfur primary battery with high rate performance and a high discharge platform, which effectively enhances the electrochemical reaction kinetics by utilizing the aforementioned alkaline ionic liquid electrolyte.

[0012] To achieve the above-mentioned objectives of this invention, the following technical solution is adopted:

[0013] An alkaline ionic liquid electrolyte, using AlCl3 as a Lewis acid, reacting with [EMIm]Cl and Cl in alkali metal chloride salts. - (Lewis base) undergoes a coordination reaction to form an alkaline ionic liquid electrolyte, the general formula of which is A. a E b X c Wherein A is aluminum chloride (AlCl3); E is 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl); X is an alkali metal chloride, specifically selected from at least one of LiCl, NaCl, KCl, RbCl, CsCl, etc.; a, b, and c are the molar proportions of the corresponding raw materials, and 0.4≤a≤0.8, 0.9≤b≤1, 0≤c≤0.1. The ionic liquid exhibits a clear liquid state at temperatures above its melting point.

[0014] The solvation structure of the ionic liquid electrolyte is influenced by the ratio of aluminum chloride (AlCl3) to 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and alkali metal chloride, as shown in the following reaction formula:

[0015] .

[0016] The resulting alkaline ionic liquid electrolyte contains Cl- as anion. - and AlCl4 - It contains the cation [EMIm]. + and X + (Li) + Na + K + 、Rb + Cs + (One or more of the following). As the value of a increases from 0.4 to 0.8, the Cl in the electrolyte... - The concentration of AlCl4 gradually decreased, while the concentration of AlCl4... - The concentration of [something] increases accordingly.

[0017] The above-mentioned method for preparing an alkaline ionic liquid electrolyte includes the following steps: under an inert atmosphere and anhydrous conditions, aluminum chloride (AlCl3), 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl), and alkali metal chloride (one or more of LiCl, NaCl, KCl, RbCl, CsCl, etc.) are accurately weighed according to the specified ratio; then, under continuous stirring, aluminum chloride is added to the mixture of [EMIm]Cl and alkali metal chloride, and the mixture is stirred until a clear liquid is formed, thereby obtaining the alkaline ionic liquid electrolyte.

[0018] Furthermore, [EMIm]Cl needs to be pretreated to remove water of crystallization before use.

[0019] Furthermore, the pretreatment can be carried out by methods such as high-temperature vacuum drying, molecular sieve drying, or heat treatment drying.

[0020] The alkaline ionic liquid electrolyte obtained according to the above scheme has a melting point of -30~-20℃, which can exhibit a wider operating temperature range; after being placed at -20℃ for 24 hours, the traditional acidic electrolyte usually solidifies, but the alkaline electrolyte of the present invention remains in a liquid state.

[0021] The present invention also provides an aluminum primary battery based on the above-mentioned alkaline ionic liquid electrolyte, which is composed of the following key components: an aluminum negative electrode, the alkaline ionic liquid electrolyte (electrolyte) described above, a separator, and a positive electrode material.

[0022] In the above scheme, the primary aluminum battery is an aluminum-fluorocarbon primary battery or an aluminum-sulfur primary battery; the positive electrode material used is a fluorocarbon-based positive electrode material (aluminum-fluorocarbon primary battery) or a sulfur-containing conductive positive electrode material (aluminum-sulfur primary battery).

[0023] Furthermore, the fluorinated carbon-based cathode material includes fluorinated carbon materials and conductive materials; the fluorinated carbon materials include, but are not limited to, at least one of fluorinated graphite, fluorinated graphene, fluorinated carbon fiber, fluorinated carbon nanotubes, etc.; the conductive materials include, but are not limited to, at least one of graphene, reduced graphene oxide, carbon nanotubes, carbon fiber materials, porous carbon materials, carbon black, activated carbon, conductive polymers, etc.

[0024] Furthermore, in the fluorinated carbon-based cathode material, the conductive polymer can be at least one of polyaniline, polypyrrole, polythiophene, etc.

[0025] Preferably, in the positive electrode of the aluminum-carbon fluoride galvanic cell, the areal loading of the fluoride carbon material is ≥1.5 mg / cm³. 2 The preferred concentration is 1.5~30 mg / cm³. 2 .

[0026] In the above scheme, the sulfur-containing conductive positive electrode material in the aluminum-sulfur primary battery includes sulfur-containing materials and conductive materials.

[0027] Preferably, the sulfur-containing material includes at least one of elemental sulfur, sulfurized polyacrylonitrile, sulfur-selenium compounds, aluminum-sulfur compounds, etc.; the conductive material includes at least one of graphene, reduced graphene oxide, carbon nanotubes, carbon fiber materials, porous carbon materials, carbon black, activated carbon, conductive polymers, etc.

[0028] Preferably, in the positive electrode of the aluminum-sulfur galvanic cell, the areal loading of sulfur is ≥1.5 mg / cm³. 2 The preferred concentration is 1.5~8 mg / cm³. 2 .

[0029] Furthermore, the alkaline ionic liquid electrolyte is in a liquid state, which allows it to fully wet the positive electrode, the separator, and the aluminum negative electrode.

[0030] Preferably, the operating temperature range of the aluminum primary battery (aluminum-carbon fluoride primary battery or aluminum-sulfur primary battery) is -10~100℃.

[0031] The present invention also provides a method for preparing the above-mentioned aluminum primary battery, comprising the following steps: obtaining a positive electrode material (conversion type), a positive electrode current collector, an aluminum negative electrode and a separator; mixing the positive electrode material with a conductive agent and a binder and coating it on the surface of the current collector to obtain a positive electrode; and then assembling and encapsulating the positive electrode, the aluminum negative electrode, the separator and the alkaline ionic liquid electrolyte.

[0032] Furthermore, the aluminum-carbon fluoride and aluminum-sulfur primary batteries can be applied to portable electronic devices (smart glasses, walkie-talkies), military and aerospace (satellites), implantable medical devices (cardiac pacemakers, nerve stimulators), Internet of Things terminals and long-term monitoring systems (sensors, smart home devices) and other fields.

[0033] Compared with the prior art, the beneficial effects of the present invention include:

[0034] (1) This invention optimizes the solvation structure of alkaline ionic liquid electrolytes in a targeted manner, resulting in a stable free Cl- in the electrolyte. - and metal cations (Li + Na + K + 、Rb + Cs + One or more of these can effectively promote the breaking of CF bonds during the discharge process of aluminum-carbon fluoride galvanic cells, and at the same time promote the breaking of SS bonds during the discharge process of aluminum-sulfur galvanic cells, thereby significantly improving the electrochemical performance of aluminum-carbon fluoride and aluminum-sulfur galvanic cells, giving them a high discharge voltage platform, excellent discharge specific capacity and excellent high rate performance.

[0035] (2) Compared with traditional acidic ionic liquid electrolytes, the alkaline ionic liquid electrolyte provided by this invention has a significantly lower melting point and can exhibit a wider operating temperature range; the alkaline ionic liquid electrolyte contains free Cl... - The enhanced coordination between ions leads to structural disorder, hindering crystal formation. This results in a glass transition with temperature changes, and the crystal can remain in a liquid state over a wide temperature range.

[0036] (3) The aluminum-carbon fluoride primary battery based on alkaline ionic liquid electrolyte described in this invention can achieve the theoretical specific capacity of fluoride (up to 865 mAh / g) with a stable discharge platform (1.1 V); which is significantly better than the aluminum-carbon fluoride primary battery based on traditional acidic ionic liquid electrolyte (the discharge platform is usually only 0.1-0.2 V and the discharge specific capacity is less than 100 mAh / g).

[0037] (4) The aluminum-sulfur primary battery based on alkaline ionic liquid electrolyte provided by the present invention exhibits a high discharge voltage platform and has excellent high-rate discharge performance, which can meet the fast discharge requirement of 1.5 C; in the positive electrode, the high specific capacity of sulfur is fully utilized, thereby significantly improving the energy density of the battery.

[0038] (5) The aluminum-carbon fluoride and aluminum-sulfur primary batteries provided by the present invention further demonstrate excellent safety performance; in the puncture test, the temperature fluctuation of the aluminum-carbon fluoride and aluminum-sulfur soft pack batteries did not exceed 0.3℃, showing excellent thermal stability; at the same time, no potential dangerous phenomena such as battery expansion, smoke or combustion were observed.

[0039] (6) The present invention can significantly reduce the manufacturing cost of aluminum-sulfur primary batteries and has significant economic and environmental benefits. Attached Figure Description

[0040] Figure 1 It is an alkaline ionic liquid electrolyte (A 0.5 E1X0, A 0.7 E1X0) and acidic electrolyte (A 1.3 Raman test results of E1X0.

[0041] Figure 2 The alkaline ionic liquid electrolyte (A) obtained in Example 1 was used. 0.4 E 0.95 X 0.08 The constant current discharge test results of the aluminum-fluorinated graphite primary cell (Application Example 1) prepared by )

[0042] Figure 3 The alkaline ionic liquid electrolyte (A) obtained in Example 1 was used. 0.4 E 0.95 X 0.08 The constant current discharge test results of the aluminum-Ketjen black / sulfur primary cell (Application Example 2) prepared by [the experiment].

[0043] Figure 4 To use the alkaline ionic liquid electrolyte (A) obtained in Example 2 0.5 E 0.95 X 0.05 The constant current discharge test results of the aluminum-fluorinated graphene primary cell (Application Example 3) prepared by )

[0044] Figure 5 To use the alkaline ionic liquid electrolyte (A) obtained in Example 2 0.5 E 0.95 X 0.05 The constant current discharge test results of the aluminum-carbon nanotube / sulfur primary battery (Application Example 4) prepared by )

[0045] Figure 6 To use the alkaline ionic liquid electrolyte (A) obtained in Example 3 0.7 E 0.9 X 0.1 The constant current discharge test results of the aluminum-fluorinated carbon fiber primary battery (Application Example 5) prepared by )

[0046] Figure 7 To use the alkaline ionic liquid electrolyte (A) obtained in Example 4 0.7 E 0.9 X 0.1 The constant current discharge test results of the aluminum-carbon nanotube / sulfur primary battery (Application Example 6) prepared by )

[0047] Figure 8 To use the alkaline ionic liquid electrolyte (A) obtained in Example 5 0.8 E 0.9 X 0.1 An aluminum-fluorinated carbon fiber primary battery (Application Example 7) was prepared with a highly active material loading (13.5 mg / cm³). 2 The constant current discharge test results under the condition of )

[0048] Figure 9 To use the alkaline ionic liquid electrolyte (A) obtained in Example 6 0.8 E 0.9 X 0.1 The results of constant current discharge test of the aluminum-fluorinated carbon fiber primary cell (Application Example 8) prepared at a high current density (100 mA / g).

[0049] Figure 10 To use the alkaline ionic liquid electrolyte (A) obtained in Example 7 0.5 E 0.95 X 0.05 The results of constant current discharge tests of aluminum-Ketjen black / sulfur primary cells at high current density (1C).

[0050] Figure 11 Comparative Example 1 uses an acidic ionic liquid electrolyte (A) 1.3 Constant current discharge test results of aluminum-fluorinated carbon fiber primary cells obtained by E1X0.

[0051] Figure 12 Comparative Example 2 used an acidic ionic liquid electrolyte (A) 1.3Constant current discharge test results of aluminum-Ketjen black / sulfur primary cells obtained by E1X0.

[0052] Figure 13 The constant current discharge test results of the aluminum-fluorinated carbon fiber primary cell obtained by Comparative Example 3 using neutral ionic liquid electrolyte (A1E1X0) are shown.

[0053] Figure 14 In Comparative Example 4, an acidic ionic liquid electrolyte (A) was used. 1.3 E 0.8 X 0.2 The constant current discharge test results of the aluminum-fluorinated carbon fiber primary cell obtained. Detailed Implementation

[0054] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0055] Figure 1 For different AlCl3 and [EMIm]Cl ratios, the resulting alkaline ionic liquid electrolytes (A... 0.5 E1X0, A 0.7 E1X0) and acidic ionic liquid electrolytes (A 1.3 Raman spectroscopy results for E1X0. The results indicate that the only ionic group present in both alkaline ionic liquid electrolytes and neutral electrolytes is AlCl4. - (Raman tests typically fail to detect Cl) - (e.g., individual ions); while acidic electrolytes contain AlCl4. - and Al2Cl7 - It has a different structure from the alkaline electrolyte obtained in this invention.

[0056] In the following examples, all operations were performed in an argon-filled glove box (conditions: O2 < 0.01 ppm, H2O < 0.01 ppm).

[0057] Before use, the EMICl was dried at 160℃ for 12 hours, cooled, and then ground into powder for later use.

[0058] Example 1

[0059] An alkaline ionic liquid electrolyte, the preparation method of which includes the following steps:

[0060] First, weigh aluminum chloride (AlCl3), 1-methyl-3-ethylimidazole chloride (EMICl), and lithium chloride (LiCl) in a molar ratio of 0.4:0.95:0.08. Under room temperature conditions, add aluminum chloride (AlCl3) to the mixture of 1-methyl-3-ethylimidazole chloride and lithium chloride (LiCl) in portions (5 to 10 times) over 30-60 minutes, stirring (200-600 rpm) to ensure complete mixing and liquefaction of all components. After the aluminum chloride has been added, continue stirring for 30-60 minutes until the system is completely liquefied and a clear ionic liquid electrolyte is formed with a melting point of -25 to -20°C.

[0061] Application Example 1

[0062] The alkaline ionic liquid electrolyte obtained in Example 1 was used to prepare an aluminum-carbon fluoride primary battery. A Swagelok-type sealed structure was adopted. The separator, positive electrode, and negative electrode were cut according to the battery model. The specific preparation method included the following steps: CF... x Cathode material (fluorinated graphite CF) x (x=1.08, stable in the obtained electrolyte system), conductive carbon black and polytetrafluoroethylene (PTFE) are mixed in a mass ratio of 7:2:1, pressed into sheets and cut to prepare positive electrode sheets, aluminum sheets are used as negative electrodes, the obtained alkaline ionic liquid electrolyte is used as electrolyte, and glass fiber is used as a separator for assembly and encapsulation.

[0063] Figure 2 The results show the electrochemical performance of the aluminum-carbon fluoride primary battery obtained in this application example. The test results indicate that the obtained aluminum-carbon fluoride primary battery exhibits a stable discharge plateau close to 1.1 V at a current density of 10 mA / g, with a discharge specific capacity of 839.03 mAh / g, demonstrating excellent discharge capacity and good electrochemical stability.

[0064] Application Example 2

[0065] The alkaline ionic liquid electrolyte described in Example 1 was used to prepare an aluminum-sulfur primary battery. A Swagelok-type sealed structure was adopted. The separator, positive electrode, and negative electrode were cut according to the battery model design. The positive electrode material was prepared as follows: Ketjen black (KB) and sulfur powder were weighed in a mass ratio of 2:3 and ground until homogeneous. The resulting mixture was placed in a mold, shaped using a hydraulic press, sealed, and placed in a 160°C oven to prepare KB / S by melt melting. After 12 hours, it was removed and ground for later use. In the preparation of the positive electrode sheet, the mass ratio of KB / S, conductive carbon black, and PTFE was 7:2:1. The aluminum sheet was used as the negative electrode, the organic ionic liquid obtained in Example 1 was used as the electrolyte, and glass fiber was used as the separator.

[0066] Figure 3 The electrochemical performance test results of the aluminum-sulfur primary battery prepared for this application example show that, at a current density of 0.1C (167.5 mA / g, the same below), the discharge specific capacity of the battery reaches 1405 mAh / g, which is close to the theoretical capacity of sulfur 1675 mAh / g, exhibiting excellent discharge performance and a stable 0.9 V discharge plateau.

[0067] The battery electrochemical performance test results of Application Example 1 and Application Example 2 show that the aluminum primary battery based on alkaline ionic liquid electrolyte described in this invention has high specific capacity and excellent discharge platform, which fully utilizes the capacity release of the positive electrode material, indicating that the positive electrode material is stable and reacts completely in alkaline ionic liquid; the resulting alkaline ionic electrolyte shows great application potential in aluminum primary batteries.

[0068] Example 2

[0069] An alkaline ionic liquid electrolyte is prepared using a method largely the same as in Example 1, with the only difference being that the molar ratio of AlCl3, [EMIM]Cl, and LiCl is 0.5:0.95:0.05. The resulting alkaline ionic liquid electrolyte has a melting point of -30 to -25°C.

[0070] Application Example 3

[0071] The alkaline ionic liquid electrolyte obtained in Example 2 was used to prepare an aluminum-carbon fluoride primary battery. A Swagelok-type sealed structure was adopted. The separator, positive electrode, and negative electrode were cut according to the battery model design. The positive electrode material introduced was fluorinated graphene (CF3). x (x=1.07); at 30℃, CF x The properties are stable in this electrolyte system; the specific preparation method of the aluminum-carbon fluoride primary battery includes the following steps: the positive electrode preparation method is the same as in Example 1, the aluminum sheet is the negative electrode, the alkaline ionic liquid electrolyte obtained in Example 2 is used as the electrolyte, and the glass fiber is used as the separator.

[0072] Figure 4 The electrochemical performance test results of the aluminum-carbon fluoride primary battery obtained in Example 3 show that at a current density of 10 mA / g, the battery exhibits a stable discharge plateau close to 1.1 V, with a discharge specific capacity of 1126.82 mAh / g, demonstrating excellent discharge capacity and good electrochemical stability.

[0073] Application Example 4

[0074] The alkaline ionic liquid electrolyte described in Example 2 was used to prepare an aluminum-sulfur primary battery. A Swagelok-type sealed structure was adopted. According to the battery model, the separator, positive electrode and negative electrode were cut. The positive electrode was prepared by weighing carbon nanotubes and sulfur powder in a mass ratio of 2:3 and preparing carbon-sulfur composite material by melting method. The specific method was the same as in Example 2.

[0075] Figure 5 The figure shows the electrochemical performance of the aluminum-carbon nanotube sulfur galvanic cell obtained in Example 4. The test data shows that the cell has a discharge plateau close to 0.9 V and a discharge specific capacity of 1571.42 mAh / g, exhibiting excellent electrochemical performance.

[0076] The excellent electrochemical performance of the aluminum-carbon nanotube sulfur galvanic cell obtained in Application Example 4 can be further attributed to its carbon framework structure, which provides efficient electronic conduction, abundant active material deposition sites, and a stable host structure.

[0077] Example 3

[0078] An alkaline ionic liquid electrolyte is prepared using a method largely the same as in Example 1, with the only difference being that alkali metal salts LiCl and NaCl are used to replace part of [EMIM]Cl; and the molar ratio of the introduced AlCl3, [EMIM]Cl, LiCl, and NaCl is 0.7:0.9:0.05:0.05. The resulting alkaline ionic liquid electrolyte has a melting point of -30 to -25°C.

[0079] Application Example 5

[0080] The alkaline ionic liquid electrolyte obtained in Example 3 was used to prepare an aluminum-fluorinated carbon fiber primary battery with a Swagelok-type sealed structure. The battery preparation method used was exactly the same as that in Example 1, except that the positive electrode material used was fluorinated carbon fiber (x=0.97). This positive electrode material is stable in the obtained electrolyte.

[0081] The corresponding organic ion electrolyte aluminum-fluorinated carbon fiber primary cell obtained in Example 5 was subjected to constant current discharge testing, and the results are as follows: Figure 6 As shown, it exhibits a high discharge specific capacity of 1004 mAh / g at a current density of 10 mA / g and a stable discharge plateau of 1.1 V, demonstrating excellent discharge performance and electrochemical stability.

[0082] Example 4

[0083] An alkaline ionic liquid electrolyte is prepared in a manner largely the same as in Example 1, except that alkali metal salts LiCl and KCl are used to replace part of [EMIM]Cl. The molar ratio of AlCl3, [EMIM]Cl, LiCl, and KCl introduced is 0.7:0.9:0.05:0.05. The resulting alkaline ionic liquid electrolyte has a melting point of -30 to -25°C.

[0084] Application Example 6

[0085] The alkaline ionic liquid electrolyte obtained in Example 4 was used to prepare an aluminum-sulfur primary battery. The preparation method was basically the same as in Example 4, except that the cathode material was a carbon nanotube-sulfur composite material. The cathode preparation method was as follows: carbon nanotubes and sulfur powder were weighed at a mass ratio of 2:3, and the carbon-sulfur composite material was prepared by melting, just like in Example 2.

[0086] The aluminum-carbon fiber sulfur galvanic cell obtained in Example 6 was subjected to constant current discharge testing. For example... Figure 7 As shown, at a current density of 0.1C (167.5 mA / g), the battery achieves a discharge specific capacity of 1300.01 mAh / g, exhibiting excellent discharge performance and a stable 0.9 V discharge plateau.

[0087] The above results indicate that when the molar ratio of AlCl3 to EMIC in the alkaline ionic liquid electrolyte is in the range of 0.4–0.8, both the resulting aluminum-carbon fluoride and aluminum-sulfur galvanic cells exhibit excellent electrochemical performance. Furthermore, this alkaline ionic liquid electrolyte demonstrates good versatility and can be effectively adapted to various fluoride carbon and sulfur cathode materials.

[0088] Example 5

[0089] An alkaline ionic liquid electrolyte is prepared in a manner largely the same as in Example 1, with the only difference being that an alkali metal salt, KCl, is used to replace part of [EMIM]Cl; and the molar ratio of AlCl3, [EMIM]Cl, and KCl introduced is 0.8:0.9:0.1. Its melting point is -25 to -20°C.

[0090] Application Example 7

[0091] The alkaline ionic liquid electrolyte obtained in Example 5 was used to prepare an aluminum-fluorinated carbon fiber primary battery using a Swagelok-type sealed structure. The battery preparation method was exactly the same as in Example 1, except that the positive electrode used had a high active material (fluorinated carbon fiber) loading (13.5 mg / cm³). 2 ).

[0092] like Figure 8As shown, at a current density of 20 mA / g, the obtained aluminum-fluorinated carbon fiber primary cell exhibits a stable discharge voltage plateau of 1.1 V and a discharge specific capacity of 816.47 mAh / g.

[0093] Example 6

[0094] An alkaline ionic liquid electrolyte is prepared using a method largely the same as in Example 1, with the only difference being that alkali metal salts LiCl, NaCl, and KCl are used to replace part of [EMIM]Cl, and the molar ratio of AlCl3, [EMIM]Cl, LiCl, NaCl, and KCl is 0.8:0.9:0.05:0.02:0.03. The resulting alkaline ionic liquid electrolyte has a melting point of -25 to -20°C.

[0095] Application Example 8

[0096] The alkaline ionic liquid electrolyte obtained in Example 6 was used to prepare an aluminum-carbon fluoride primary battery. The preparation method was basically the same as in Example 1, and the positive electrode material was fluorinated carbon fiber (fluorine-carbon ratio 0.89).

[0097] like Figure 9 As shown, at a current density of 100 mA / g, the obtained aluminum-fluorinated carbon fiber primary cell exhibits a stable discharge voltage plateau of 0.9 V and a discharge specific capacity of 800 mAh / g, indicating that the cell has excellent rate performance.

[0098] Application Example 9

[0099] The alkaline ionic liquid electrolyte obtained in Example 2 was used to prepare an aluminum-sulfur primary battery. The preparation method was basically the same as in Example 1, and the cathode material used was the same as in Application Example 2.

[0100] like Figure 10 As shown, at a high current density of 1C (1675mA / g), the Al-KB / S primary cell can still maintain a high voltage plateau and achieve a discharge specific capacity of 1283.51 mAh / g, demonstrating excellent rate performance.

[0101] Comparative Example 1

[0102] An acidic ionic liquid electrolyte was prepared using a method largely the same as in Example 1, the only difference being that AlCl3 and 1-methyl-3-ethylimidazole chloride (EMICl) were prepared in a molar ratio of 1.3:1, and the test temperature was also 30°C. The resulting acidic ionic liquid electrolyte had a freezing point of approximately -1°C.

[0103] The acidic ionic liquid electrolyte obtained in this comparative example was used to prepare an aluminum-fluorinated carbon fiber primary battery, using a Swagelok-type sealed structure. The specific battery preparation method was the same as in Example 1.

[0104] The aluminum-fluorinated carbon fiber galvanic cell prepared in this comparative example was subjected to constant current discharge testing. The same current density of 10 mA / g was used for testing. Figure 11 As shown, the battery exhibits poor discharge capacity and plateau.

[0105] As can be seen from Example 1, under the same current density and test temperature, the aluminum-carbon fluoride battery using an acidic electrolyte system has poor electrochemical performance.

[0106] Comparative Example 2

[0107] The acidic ionic liquid electrolyte obtained in Comparative Example 1 was used to prepare an aluminum-sulfur primary battery using a Swagelok-type sealed structure. The battery preparation method used was exactly the same as that in Example 1.

[0108] like Figure 12 As shown, at a current density of 0.1C (167.5 mAh / g), the discharge voltage plateau of the Al-KB / S galvanic cell with a molar ratio of aluminum chloride (AlCl3) to 1-ethyl-3-methylimidazolium chloride (EMIC) of 1.3:1 is 0.4 V, which is significantly lower than the discharge plateau of the cell using an alkaline electrolyte.

[0109] Comparative Example 3

[0110] A neutral ionic liquid electrolyte was prepared using a method largely the same as in Example 1, except that AlCl3 and 1-methyl-3-ethylimidazole chloride (EMICl) were weighed in a 1:1 molar ratio, and the testing temperature was also 30°C. The resulting neutral ionic liquid electrolyte had a melting point of approximately -1°C.

[0111] The neutral ionic liquid electrolyte obtained in this comparative example was used to prepare an aluminum-fluorinated carbon fiber primary battery, using a Swagelok-type sealed structure. The specific battery preparation method was the same as in Example 1.

[0112] The aluminum-fluorinated carbon fiber galvanic cell prepared in this comparative example was subjected to constant current discharge testing. The same current density of 10 mA / g was used for testing. Figure 13 As shown, the battery exhibits poor discharge capacity and plateau.

[0113] Comparative Example 4

[0114] An acidic ionic liquid electrolyte is prepared in a manner largely the same as in Example 1, except that: alkali metal salt KCl is used to replace part of [EMIM]Cl, and the molar ratio of AlCl3, [EMIM]Cl and KCl introduced is 1.3:0.8:0.2.

[0115] The acidic ionic liquid electrolyte obtained in this comparative example was used to prepare an aluminum-fluorinated carbon fiber primary battery, using a Swagelok-type sealed structure. The specific battery preparation method was the same as in Example 1.

[0116] The aluminum-fluorinated carbon fiber galvanic cell prepared in this comparative example was subjected to constant current discharge testing. The same current density of 10 mA / g was used for the tests. Figure 14 As shown, compared to A 1.3 E1X0 electrolyte, introducing alkali metal cations K + The discharge specific capacity was significantly improved, reaching 1003.18 mAh / g, and the voltage plateau was also improved (0.2-0.4V); indicating that the introduction of alkali metal cations can promote the improvement of kinetic effect to a certain extent; however, there is still a significant gap compared with the voltage plateau (1.1V) of the aluminum-carbon fluoride battery based on alkaline electrolyte described in this invention.

[0117] Comparative Example 5

[0118] An alkaline ionic liquid electrolyte is prepared in a manner largely similar to that in Example 1, with the only difference being that the molar ratio of aluminum chloride (AlCl3) to 1-methyl-3-ethylimidazole chloride (EMICl) is 0.3:1. Under room temperature conditions, aluminum chloride (AlCl3) is added to 1-methyl-3-ethylimidazole chloride in portions over 30-60 minutes. After thorough stirring (200-600 rpm), some of the aluminum chloride and 1-methyl-3-ethylimidazole chloride (EMICl) remain as solids, indicating that the electrolyte cannot be uniformly mixed when there is insufficient aluminum chloride (AlCl3), and therefore cannot be effectively used in the preparation of aluminum primary batteries.

[0119] The constant current discharge performance of the aluminum-galvanic cells prepared with ionic liquid electrolytes in the above embodiments and comparative examples was tested respectively, and the test results are shown in Table 1.

[0120] Table 1. Test results of discharge performance of aluminum primary batteries in application examples and comparative examples.

[0121]

[0122] As can be seen from Table 1, the aluminum primary cells prepared in each embodiment have high discharge specific capacity and a very stable discharge plateau in the alkaline electrolyte system.

[0123] In Comparative Examples 1 and 2, the ionic liquid electrolyte was acidic, resulting in extremely low discharge capacity and no obvious discharge plateau. The battery performance was unstable, indicating that the cathode material had lower reactivity, which prevented the capacity from being fully released.

[0124] In Comparative Example 3, the ionic liquid electrolyte was neutral, and the majority of the anions in the electrolyte were AlCl4. -Lack of Cl - This prevents the reaction on the negative electrode side from proceeding, resulting in poor discharge performance.

[0125] Although the present invention has been described through specific embodiments, it should be understood that these embodiments are only used to illustrate technical solutions and do not constitute a limitation of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions in the embodiments without departing from the spirit and scope of the present invention, and such modifications or substitutions will not exceed the technical scope of the present invention. Therefore, the appended claims should include all such substitutions and modifications.

Claims

1. An alkaline ionic liquid electrolyte, characterized in that, It is the Cl in aluminum chloride and 1-ethyl-3-methylimidazolium chloride and alkali metal chlorides. - The alkaline ionic liquid electrolyte produced by the coordination reaction; the general formula of the raw material component is A. a E b X c Where A is aluminum chloride; E is 1-ethyl-3-methylimidazolium chloride; X is an alkali metal chloride; a, b, and c are the molar percentages of the corresponding raw materials, and 0.4≤a≤0.8, 0.9≤b≤1, and 0.02≤c≤0.1; The melting point of the alkaline ionic liquid electrolyte is -30 to -20°C.

2. The alkaline ionic liquid electrolyte according to claim 1, characterized in that, The alkali metal chloride is at least one of LiCl, NaCl, KCl, RbCl, and CsCl.

3. The alkaline ionic liquid electrolyte according to claim 1, characterized in that, In alkaline ionic liquid electrolytes, the anions include Cl-. - and AlCl4 - The cation contains [EMIm] + And alkali metal ions.

4. The method for preparing the alkaline ionic liquid electrolyte according to any one of claims 1 to 3, characterized in that, The process includes the following steps: under an inert atmosphere, anhydrous conditions, and stirring, aluminum chloride is added to a mixture of 1-ethyl-3-methylimidazolium chloride and alkali metal chloride, and the mixture is stirred to form a clear liquid, thus obtaining the alkaline ionic liquid electrolyte.

5. The preparation method according to claim 4, characterized in that, The stirring speed used is 200~600 rpm.

6. An aluminum primary battery based on the alkaline ionic liquid electrolyte according to any one of claims 1 to 3, characterized in that, The aluminum primary battery consists of the following key components: an aluminum negative electrode, an alkaline ionic liquid electrolyte, a separator, and a positive electrode.

7. The aluminum primary battery according to claim 6, characterized in that, The primary aluminum battery is either an aluminum-carbon fluoride primary battery or an aluminum-sulfur primary battery; the positive electrode material used is either a fluoride-carbon based positive electrode material or a sulfur-containing conductive positive electrode material.

8. The aluminum primary battery according to claim 6, characterized in that, The operating temperature range of the aluminum primary battery is -10~100℃.

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