A dynamic alloy co-deposition co-stripping electrolyte for aluminum metal batteries, methods and batteries

Abstract

The application discloses a dynamic alloy co-deposition and co-stripping electrolyte for an aluminum metal battery, a method and the battery, and relates to the technical field of aluminum metal batteries.The application comprises a halogen aluminate system electrolyte and a soluble precursor of an alloying metal M; the halogen aluminate system electrolyte contains an aluminum halogen complex active species; the alloying metal M is one or more of metal elements capable of alloying with aluminum and forming a metal element capable of participating in an electrochemical interface process in the halogen aluminate system.By introducing the soluble precursor of the alloying metal M into the halogen aluminate system, the alloying metal M participates in the interface reaction process during aluminum deposition and / or aluminum stripping, thereby adjusting the nucleation and growth behavior of aluminum, improving the uniformity of aluminum deposition and reducing the dendrite / protrusion growth tendency, and improving the stability and controllability of the aluminum deposition / stripping process.

Description

Technical Field

[0001] This invention belongs to the field of aluminum metal battery technology, and in particular relates to a dynamic alloy co-deposition and co-stripping electrolyte, method and battery for aluminum metal batteries. Background Technology

[0002] Against the backdrop of "dual carbon" goals and the large-scale integration of renewable energy, large-scale energy storage and safe, low-cost rechargeable battery technologies have received continuous attention. Compared to lithium systems, aluminum resources are abundant, low-cost, and have a high theoretical volumetric capacity, possessing the potential to construct low-cost, high-safety energy storage systems. Regarding rechargeable aluminum metal batteries, existing technologies typically employ aluminohalate electrolytes (including aluminohalate ionic liquids and molten aluminohalate salts), with AlX4 as the primary electrolyte. − / Al2X7 − (X represents Cl, Br, etc.) As the main active aluminum species, they typically possess high ionic conductivity and fast interfacial kinetics, thus being used in aluminum deposition / stripping batteries (such as Al||graphite intercalation systems) and related electrochemical devices. However, during aluminum deposition at high current densities or with large areal capacities, aluminum nucleation and growth are prone to spatial inhomogeneity, leading to dendrite / protrusion growth, interface coarsening, and the risk of localized short circuits, which in turn cause increased polarization, decreased coulombic efficiency, and shortened cycle life. To address these issues, existing technologies mainly follow two routes: one is electrolyte formulation modification, and the other is electrode interface engineering or alloying strategies.

[0003] Regarding electrolyte formulations, existing patents have proposed adding components such as dendrite inhibitors, viscosity modifiers, and corrosion inhibitors to aluminohalate ionic liquid electrolytes to reduce viscosity, improve conductivity, and reduce aluminum dendrite formation at high current densities. For example, CN105870453A / B discloses an electrolyte for aluminum batteries, in which the main component is a specific aluminohalate ionic liquid, and dendrite inhibitors (such as potassium nitrate, thionyl chloride, etc.), viscosity modifiers, and corrosion inhibitors are added to "reduce the generation of aluminum dendrites at high current densities and improve cycle performance." Furthermore, its aluminum halide component allows for the selection of aluminum chloride or aluminum bromide, thus covering the chlorine / bromine system. Such solutions typically adjust electrolyte properties or interfacial reaction processes by introducing additives such as small molecules / inorganic salts, but their dendrite-suppressing effect often depends on the long-term stable presence of the additives in the electrolyte; under high areal capacity and long-term deposition conditions, problems such as interfacial morphology instability may still occur.

[0004] Regarding haloaluminate electrolyte systems and aluminum battery configurations, earlier patents have disclosed rechargeable aluminum batteries and their haloaluminate ionic liquid electrolyte systems to achieve reversible deposition / stripping of aluminum and full-cell cycling. For example, CN101764253A discloses a secondary aluminum battery with an aluminum or aluminum alloy as the negative electrode and a haloaluminate ionic liquid as the electrolyte. The ionic liquid environment prevents the formation of a passivation oxide film on the aluminum negative electrode surface and enables rechargeability. However, these prior technologies focus on the rechargeability of the system and the availability of the electrolyte, and do not provide a solution for continuous and effective interface control during long-term cycling to address the problems of dendrite formation and continuous interface instability under high current density and high areal capacity conditions.

[0005] In terms of interface engineering / alloying strategies, numerous patents and studies related to metal anodes have shown that constructing alloy layers, seed layers, or surface modification layers can, to some extent, regulate nucleation, achieve uniform current distribution, and suppress dendrite growth. Taking lithium metal anodes as an example, patent CN113793920B discloses the idea of ​​constructing a lithium-aluminum alloy layer in situ on the surface of lithium metal to reduce interfacial activity, increase nucleation sites, and suppress dendrite growth. When similar concepts are applied to aluminum deposition systems, they typically involve first forming an alloyed layer or a low-activity layer on the substrate, followed by the deposition of the main aluminum layer (i.e., "sequential alloying / pre-alloying / seed layer"). However, this sequential strategy has inherent limitations: as deposition continues, subsequent aluminum deposition can easily cover and "bury" the early alloyed layer, leading to a decrease in the regulatory effect; simultaneously, alloying elements or modification layers may remain during the stripping process, causing pores and uneven roughness at the interface, which can exacerbate the tendency for uneven nucleation and dendrite growth in the next cycle.

[0006] Currently, the dendrite suppression methods for aluminum batteries based on aluminohalate systems mainly involve regulating electrolyte properties and interfacial reactions through electrolyte additives, or improving the nucleation and deposition morphology of aluminum through interface engineering such as pre-alloying / seed layers. However, these methods generally suffer from problems such as uneven deposition, gradual deterioration of interfacial morphology, and insufficient cycle stability under high current density and high areal capacity conditions. Therefore, developing an electrolyte system and interface control strategy that can stably suppress aluminum dendrites under harsh operating conditions, improve the reversibility of aluminum deposition / stripping, and meet the requirements of high power and long lifespan is of great significance for improving the cycle stability and engineering application feasibility of rechargeable aluminum metal batteries. Summary of the Invention

[0007] The purpose of this invention is to provide a dynamic alloy co-deposition and co-stripping electrolyte, method, and battery for aluminum metal batteries. By introducing a soluble precursor of alloying metal M into the aluminohalate system, it participates in the interfacial electrochemical reaction process during aluminum deposition and / or aluminum stripping, thereby regulating the nucleation and growth behavior of aluminum, improving the uniformity of aluminum deposition and reducing the tendency of dendrite / protrusion growth, and enhancing the stability and controllability of the aluminum deposition / stripping process.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A dynamic alloy co-deposition and co-stripping electrolyte for aluminum metal batteries includes a haloaluminate system electrolyte and a soluble precursor of alloying metal M.

[0010] The haloaluminate system electrolyte refers to an electrolyte system containing aluminum halide complex anions, which can be formed by AlX3 and one or more halide salts (or salts that can provide the corresponding halide anions), where X is a halogen. The system can be a molten salt or an ionic liquid. The haloaluminate system may contain one or more aluminum halide complex anions. Aluminum halide complex anions refer to aluminum halide complex anions or related species in their equilibrium system that can participate in the electrochemical reaction of aluminum deposition / stripping at the electrode interface, preferably including but not limited to AlX4⁻ and Al2X7⁻ (X is a halogen). This invention is not necessarily limited to the exclusive presence of a specific species.

[0011] The alloying metal M refers to a metallic element that can alloy with aluminum and be used to regulate aluminum deposition / stripping behavior. M can be introduced into the aluminohalate system as a soluble precursor and exists in the electrochemical process as a metal halide complex, ion pair, cluster, or other forms that can participate in the electrochemical process; this invention does not necessarily limit it to a specific complex structure.

[0012] The alloying metal M is preferably selected to meet one or a combination of the following conditions: it can form a reducible metal halide complex active species in the aluminohalate system; its precursor is soluble in the electrolyte or can form a stable complex; it can undergo deposition or co-deposition with aluminum within the aluminum deposition potential window, thereby enabling M to participate in aluminum deposition and exhibit co-deposition characteristics; in embodiments including deposition-stripping cycles, M can also exhibit reversible participation characteristics during stripping. The above conditions are used to illustrate preferred selection principles and do not constitute the only limitation on the alloying metal M. The present invention further preferably includes: the aluminum halide complex active species being a chlorine system, a bromine system, an iodine system, or a mixed halide system; and the alloying metal M being selected from one or more of Mn, Mg, Fe, Co, Ni, Cr, V, Ti, Zn, Sn, Bi, and Sb.

[0013] Preferably, the alloying metal M is selected from one or more of Mn, Mg, Zn, and Sn;

[0014] More preferably, the alloying metal M is Mn.

[0015] The present invention is further preferred in that: the soluble precursor of the alloying metal M is a halide of M, or other salts or complexes that can be converted into corresponding active metal species in the aluminohalate system;

[0016] The halide of M is MCl. x ,MBr x or MI x , where x is 2 or 3;

[0017] The salts or complexes include, but are not limited to, one or more of MnCl2, MgCl2, ZnCl2 and SnCl2;

[0018] The precursor of the alloying metal M can be added within a certain concentration range to meet different deposition conditions; preferably, its influence on deposition behavior can be adjusted by changing the metal salt concentration. Preferably, the amount of the soluble precursor of the alloying metal M added to the haloaluminate electrolyte is 0.1–20 mol%; more preferably 0.5–10 mol%.

[0019] The present invention also includes an alloy co-deposition and co-stripping method, wherein only aluminum deposition is performed in the electrolyte, so that alloy metal M is co-deposited with aluminum to form a deposition layer or interface layer containing alloy metal M on the electrode surface.

[0020] The present invention also includes a dynamic alloy co-deposition and co-stripping method for aluminum metal, wherein aluminum deposition and / or stripping operations are performed on aluminum electrodes in the above-mentioned electrolyte.

[0021] The alloying metal M participates in the interfacial electrochemical process during deposition and / or stripping operations, forming a deposition layer or interfacial layer containing the alloying metal M on the electrode surface, thereby regulating the morphology of aluminum deposition.

[0022] A further preferred embodiment of the present invention is that the method comprises the following steps:

[0023] S1) Assemble the electrochemical system: Use aluminum metal as the working electrode or the two electrodes of a symmetrical battery, place a membrane between the electrodes, add the above electrolyte, and obtain an electrochemical device;

[0024] S2) Deposition step: Apply deposition current or deposition potential to the electrochemical device to reduce and deposit aluminum active species on the electrode surface. The alloying metal M comes from the electrolyte and participates in the deposition interface process.

[0025] S3) Stripping step: Apply stripping current or stripping potential to the electrochemical device to oxidize and strip the deposited aluminum, and the alloyed metal M participates in the stripping interface process.

[0026] S4) Perform S2 once or alternately repeat S2 and S3 to form at least one deposition-stripping cycle, and may further repeat the deposition-stripping cycle; the cycle may start from the deposition step or from the stripping step, preferably from the deposition step;

[0027] The method is applicable to aluminum deposition scenarios with high current density or large area capacity.

[0028] The present invention also includes an aluminum metal battery, comprising a positive electrode, a separator, a negative electrode, and the electrolyte described in the claims above, wherein the negative electrode is an aluminum metal negative electrode, and the aluminum negative electrode is deposited and / or stripped using the method described above.

[0029] A further preferred embodiment of the present invention is that the aluminum metal battery is an aluminum symmetrical battery or an aluminum metal full battery.

[0030] The present invention is further preferred in that the positive electrode of the aluminum metal full battery is an intercalation type positive electrode material or other positive electrode material suitable for a haloaluminate system.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention introduces a soluble precursor of alloying metal M into the haloaluminate system, enabling it to participate in the interfacial reaction process during aluminum deposition and / or aluminum stripping, thereby regulating the nucleation and growth behavior of aluminum, improving the uniformity of aluminum deposition and reducing the tendency of dendrite / protrusion growth, and enhancing the stability and controllability of the aluminum deposition / stripping process.

[0033] 2. The system proposed in this invention has good long-term cycle stability of aluminum anode: The introduced alloying metal M participates in the interfacial reaction during aluminum deposition and / or aluminum stripping, and exhibits reversible participation and regeneration characteristics in the system, so that the interface regulation effect does not depend on the one-time prefabricated layer or short-term effective additives, thus being less affected by the running time, which is conducive to reducing interface roughness and defect accumulation and improving the long-term cycle stability of aluminum anode.

[0034] 3. The electrolyte and method proposed in this invention have good device compatibility and scalability: This invention can be used in devices such as symmetric cells related to aluminum deposition / stripping and aluminum metal full cells, and can be used in combination with different aluminohalate systems (chlorine / bromine / iodine / mixed halides) and different alloying metals M, providing a new technical path for the design of electrolytes and interface control for aluminum metal batteries under different application requirements.

[0035] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a comparative illustration of the existing sequential alloying / seed layer (static control) and the strategy of this invention (introducing metal M into the electrolyte, and participating in the interface process through deposition / stripping);

[0038] Figure 2 This serves as the basis for determining differences in deposition behavior under different electrochemical conditions;

[0039] Figure 3 The X-ray diffraction (XRD) pattern of the aluminum deposition product in Example 1 of this invention;

[0040] Figure 4 This is a graph showing the deposition / stripping cycle performance of the Al‖Al symmetric cell under constant current conditions in Example 1 of this invention;

[0041] Figure 5 The graph shows the cycling performance of the aluminum metal full cell (Al‖graphite) in Example 1 of this invention under constant current conditions.

[0042] Figure 6 This is a comparison chart of the maximum initial deposition capacity of Al|Mo half-cells with different MnCl2 contents in Example 2 of the present invention;

[0043] Figure 7 This is a comparison chart of the cycle performance of Al‖Al symmetric batteries with different MnCl2 contents in Example 2 of the present invention;

[0044] Figure 8 This is a graph showing the deposition / stripping cycle performance of the Al‖Al symmetric cell under constant current conditions in Example 3 of the present invention;

[0045] Figure 9 This is a graph showing the deposition / stripping cycle performance of the Al‖Al symmetric cell under constant current conditions in Example 4 of the present invention. Detailed Implementation

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0048] Unless otherwise stated, "%" in this document refers to the mole fraction (mol%) relative to the molten salt electrolyte of the haloaluminate system.

[0049] Please see Figure 1 , Figure 1 a is a schematic diagram of the existing sequential alloying / seed layer strategy, showing that when the alloying layer is pre-formed and the main aluminum is deposited, the alloying layer may be covered by the subsequent deposited layer and generate residue and interface defect accumulation during the peeling process.

[0050] Figure 1 b is a schematic diagram of the strategy of the present invention, showing that after introducing alloying metal components into the electrolyte of the haloaluminate system, the alloying metal components participate in the interfacial electrochemical process during aluminum deposition and / or aluminum stripping, thereby regulating the nucleation and growth behavior of aluminum.

[0051] Please see Figure 2 In a molten salt electrolyte system containing 3% MnCl2, the voltage curves of the Al|Mo half-cell under different current densities during the first cycle of constant current deposition are used to characterize the characteristics of the deposition voltage response as a function of current density and to determine the electrochemical condition window for Al–Mn co-deposition.

[0052] Based on the above Figure 1-2 The following specific embodiments are provided in this application.

[0053] Specific Example 1: A haloaluminate electrolyte system containing 3% MnCl2

[0054] Please see Figure 3-5 This embodiment provides a preferred electrolyte formulation of the present invention and its application in an aluminum deposition / stripping system. First, a molten salt electrolyte based on a haloaluminate system is prepared as the base electrolyte. The molten salt electrolyte based on the haloaluminate system can be prepared by mixing AlX3 with one or more halide salts under an inert atmosphere and heating to melt, where X is a halogen. Preferably, the molten salt electrolyte based on the haloaluminate system is an AlCl3–NaCl–KCl system, prepared with a molar ratio of KCl:NaCl:AlCl3 = 0.375:0.625:1.56; after mixing in an inert atmosphere with controlled water and oxygen content, it is melted at approximately 140°C and held at that temperature until the system is homogeneous. After cooling, it is set aside and electrochemically tested at approximately 110°C. 3% MnCl2 is added to this base electrolyte, and mixing / holding is continued under molten conditions until the MnCl2 is fully and uniformly dispersed or dissolved in the system, thereby obtaining a homogeneous MnCl2-containing haloaluminate system electrolyte.

[0055] Subsequently, an aluminum deposition system was constructed using the electrolyte, and aluminum deposition experiments were conducted: a metal substrate (e.g., an inert conductor substrate such as Mo) was used as the working electrode, and aluminum metal was used as the counter / reference electrode. After adding the electrolyte, a deposition current or deposition potential was applied, causing aluminum active species to undergo reduction deposition on the surface of the working electrode to form a deposition layer. The deposition product was characterized by XRD. The XRD results showed that the deposition product exhibited diffraction features related to Al–Mn alloying, indicating that Mn participated in and entered the deposition product during the deposition process, forming a deposition phase structure with alloying characteristics, such as... Figure 3 As shown; Figure 3 X-ray diffraction (XRD) patterns of aluminum deposits obtained under optimal electrolyte conditions are used to characterize the crystal structure and phase composition of the deposits and to demonstrate that the deposits contain Al–M alloying-related phases.

[0056] Based on this, an aluminum symmetrical battery was assembled using aluminum metal as the two electrodes: two aluminum metal electrodes were placed opposite each other, a separator was placed between the two electrodes, and the above-mentioned haloaluminic acid electrolyte containing 3% MnCl2 was added to assemble the symmetrical battery. A constant current deposition / stripping test was applied to the symmetrical battery (deposition and stripping could be performed alternately in cycles), and the voltage response during the cycle was recorded. The symmetrical battery was tested at approximately 110 °C. The separator was preferably a glass fiber separator (e.g., GF / D), and the electrolyte amount was sufficient to fully wet the separator. Deposition / stripping was performed using a constant current method, with a preferred current density of 2 mA cm⁻² and a preferred areal capacity of 2 mAh cm⁻². Figure 4 As shown, the test results indicate that the symmetrical cell exhibits stable voltage response and minimal polarization fluctuations during deposition / stripping cycling, and no abrupt failure characteristics were observed during the cycling process. This data reflects the voltage response characteristics and stability of the system during deposition / stripping, thus demonstrating the improvement effect of the present invention's technical solution on the deposition / stripping behavior of aluminum anodes.

[0057] Furthermore, an aluminum metal full cell is assembled using an embedded positive electrode (e.g., a graphite positive electrode) and an aluminum metal negative electrode: the positive electrode, separator, and aluminum negative electrode are assembled sequentially, and the aforementioned haloaluminate electrolyte containing 3% MnCl2 is added to obtain the aluminum metal full cell. The full cell is tested within the temperature range where the haloaluminate molten salt can operate stably, preferably around 110 °C, with the current density / rate set according to the mass load of the positive electrode material. Charge-discharge cycle tests are performed on the full cell. The test results show that the full cell exhibits a stable cycling process and maintains a good capacity retention trend, indicating that the preferred electrolyte and corresponding method of this invention are suitable for battery configurations at the device level, such as… Figure 5 As shown; Figure 5This is used to reflect the cyclic behavior characteristics of the full battery, such as voltage response and capacity retention, during the charging and discharging process, thereby illustrating the applicability and stability improvement effect of the technical solution of the present invention at the device level.

[0058] Specific Example 2: A haloaluminate electrolyte system containing 1%–10% MnCl2

[0059] Please see Figure 6-7 This embodiment illustrates that when the amount of MnCl2 added varies within a certain range, the technical solution of the present invention can achieve co-deposition and co-exfoliation involving Mn, and the deposition capacity and cycle stability show a regular change with the MnCl2 concentration. Using the same molten salt electrolyte system as in Example 1 as the substrate, 1%, 3%, 5%, and 10% MnCl2 were added respectively, and the mixture was thoroughly mixed under molten conditions and kept at a constant temperature until the system was homogeneous, thereby obtaining molten salt electrolyte systems with different MnCl2 concentrations. An electrolyte system without MnCl2 was used as a control for comparison.

[0060] Aluminum deposition / stripping test systems (preferably aluminum symmetric cells) were constructed using electrolytes of different concentrations: aluminum metal was used as the two electrodes, a diaphragm was placed between the electrodes and the corresponding electrolyte was added to assemble a symmetric cell, and constant current deposition / stripping tests were performed under the same test conditions to evaluate: (i) whether Mn participates in the deposition process and exhibits co-deposition characteristics and subsequent co-stripping characteristics; (ii) the maximum deposition capacity achievable in a single deposition; and (iii) the cycle stability and cycle life under alternating deposition / stripping cycle conditions.

[0061] Test results show that when the MnCl2 concentration is between 1% and 10%, the system can achieve Mn-involved co-deposition and subsequent co-exfoliation processes, indicating that the technical solution described in this invention has good feasibility and repeatability within this concentration range. Furthermore, within the range of 0%–5%, the maximum deposition capacity achievable in a single deposition increases significantly with increasing MnCl2 concentration, such as... Figure 6 As shown; Figure 6 This is a comparison of the initial capacity-limiting deposition voltage curves of Al|Mo half-cells in haloaluminate electrolyte systems with different MnCl2 concentrations under constant current conditions. This is used to characterize and compare the maximum depositable capacity under each electrolyte system, thereby illustrating the influence of MnCl2 concentration on the upper limit of deposition capacity and the stability of the deposition process.

[0062] The deposition / stripping cycle life also showed a synchronous increasing trend, such as Figure 7 As shown; Figure 7In the figure, the deposition / stripping cycle performance of Al‖Al symmetric cells under constant current conditions is compared in haloaluminate electrolytes containing different amounts of MnCl2 (e.g., 1%, 3%, 5%). The inset shows the voltage curves over a specific time period, used to characterize the effect of MnCl2 concentration changes on the voltage response and cycle stability of the symmetric cells, indicating that adjusting the MnCl2 concentration can enhance the interface regulation and improve the stability of the deposition / stripping process.

[0063] Specific Example 3: A haloaluminate electrolyte system containing 10% MgCl2

[0064] Please see Figure 8 This embodiment provides a MgCl2-introduced haloaluminic acid system electrolyte and its application in an aluminum deposition / stripping system. First, a molten salt electrolyte of haloaluminic acid system is prepared as a base electrolyte. 10% MgCl2 is added to the base electrolyte and the mixture is thoroughly mixed and kept warm under molten conditions until the system is homogeneous, thereby obtaining a MgCl2-containing haloaluminic acid system electrolyte with homogeneous composition.

[0065] Subsequently, aluminum deposition / stripping tests were conducted using the MgCl2-containing electrolyte. Preferably, an aluminum symmetrical cell was assembled: two aluminum metal electrodes were placed opposite each other, a separator was placed between the two electrodes, and the aforementioned electrolyte was added to assemble the symmetrical cell. A deposition / stripping test was performed on the symmetrical cell using a constant current method (deposition and stripping could be performed alternately in cycles), and the voltage response during the cycle was recorded.

[0066] Test results show that in a haloaluminate electrolyte containing 10% MgCl2, Mg-related components can participate in the deposition / stripping interface process and exhibit co-deposition characteristics. Simultaneously, the deposition / stripping process of the symmetric cell exhibits improved stability compared to the baseline haloaluminate electrolyte. Figure 8 As shown; Figure 8 This is used to reflect the voltage response characteristics and stability of the system during the deposition / stripping process, thereby illustrating the improvement effect of the technical solution of the present invention on the deposition / stripping behavior of aluminum anodes.

[0067] Specific Example 4: A haloaluminate system electrolyte containing ZnCl2

[0068] Please see Figure 9 This embodiment provides a haloaluminate system electrolyte incorporating ZnCl2 and its application in an aluminum deposition / stripping system. First, a haloaluminate system molten salt electrolyte is prepared as the base electrolyte. Then, 10% ZnCl2 is added to this base electrolyte, and the mixture is thoroughly mixed under molten conditions and kept at a constant temperature until the system becomes homogeneous, thereby obtaining a homogeneous ZnCl2-containing haloaluminate system electrolyte.

[0069] Subsequently, aluminum deposition / stripping tests were conducted using the ZnCl2-containing electrolyte. Preferably, an aluminum symmetrical cell was assembled: two aluminum metal electrodes were placed opposite each other, a separator was placed between the two electrodes, and the aforementioned electrolyte was added to assemble the symmetrical cell. A deposition / stripping test was performed on the symmetrical cell using a constant current method (deposition and stripping could be performed alternately in cycles), and the voltage response during the cycle was recorded.

[0070] Test results show that in the ZnCl2-containing haloaluminic acid electrolyte system, Zn-related components can participate in the interfacial electrochemical process and exhibit co-deposition characteristics during deposition. Simultaneously, the deposition / stripping process of the symmetrical cell exhibits corresponding electrochemical responses and stability characteristics, such as... Figure 9 As shown; Figure 9 This is used to reflect the voltage response characteristics and stability of the system during the deposition / stripping process, thereby illustrating the improvement effect of the technical solution of the present invention on the deposition / stripping behavior of aluminum anodes.

[0071] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A dynamic alloy co-deposition and co-stripping electrolyte for aluminum metal batteries, characterized in that: Including soluble precursors of haloaluminate system electrolytes and alloyed metal M; The haloaluminate system electrolyte contains aluminum halide complexed active species. The electrolyte enables the alloyed metal M and aluminum to be co-deposited on the electrode surface, and during the stripping process, at least part of the alloyed metal M and aluminum are stripped together into the electrolyte; The alloying metal M is one or more of the metal elements that can alloy with aluminum and form an electrochemical interface process in the aluminohalate system.

2. The dynamic alloy co-deposition and co-stripping electrolyte for aluminum metal batteries according to claim 1, characterized in that, The aluminum halide complex active species is a chlorine system, a bromine system, an iodine system, or a mixed halide system; the alloying metal M is one or more of Mn, Mg, Fe, Co, Ni, Cr, V, Ti, Zn, Sn, Bi, and Sb.

3. The dynamic alloy co-deposition and co-stripping electrolyte for aluminum metal batteries according to claim 2, characterized in that, The soluble precursor of the alloying metal M is a halide of M, or other salts or complexes that can be converted into corresponding active metal species in the aluminohalate system. The halide of M is MClx, MBrx or MIx, where x is 2 or 3; The salts or complexes include, but are not limited to, one or more of MnCl2, MgCl2, ZnCl2 and SnCl2; The amount of the soluble precursor of the alloying metal M added to the haloaluminate electrolyte is 0.1–20 mol.

4. A method for dynamic alloy co-deposition and co-exfoliation of aluminum metal, characterized in that: In the electrolyte according to any one of claims 1-3, an aluminum deposition operation is performed on the aluminum electrode to deposit the alloyed metal M together with the aluminum, thereby forming a deposition layer or interface layer containing aluminum and the alloyed metal M on the electrode surface.

5. The dynamic alloy co-deposition and co-exfoliation method for aluminum metal according to claim 4, characterized in that, At least one deposition-stripping cycle is performed on the aluminum electrode in the electrolyte; During the deposition process, the alloyed metal M and aluminum are deposited together to form a deposition layer containing M; During the stripping process, at least a portion of the alloyed metal M is stripped together with the aluminum into the electrolyte.

6. The dynamic alloy co-deposition and co-exfoliation method for aluminum metal according to claim 5, characterized in that, Includes the following steps: S1) Assemble the electrochemical system: Use aluminum metal as the working electrode or the two electrodes of a symmetrical battery, set a membrane between the electrodes, and add the electrolyte to obtain an electrochemical device. S2) Deposition step: Apply deposition current or deposition potential to the electrochemical device to reduce and deposit aluminum active species on the electrode surface. The alloying metal M comes from the electrolyte and participates in the deposition interface process. S3) Stripping step: Apply stripping current or stripping potential to the electrochemical device to oxidize and strip the deposited aluminum, and the alloyed metal M participates in the stripping interface process. S4) Depending on the application requirements, execute S2 or S3 once, or alternately repeat S2 and S3 to achieve multiple deposition / stripping cycles; the cycle can start from the deposition step or from the stripping step, preferably from the deposition step.

7. An aluminum metal battery, characterized in that, The method includes a positive electrode, a separator, a negative electrode, and an electrolyte as described in any one of claims 1-3, wherein the negative electrode is an aluminum metal negative electrode, and the aluminum negative electrode is deposited and / or stripped using the method described in any one of claims 4-6.

8. An aluminum metal battery according to claim 7, characterized in that, The aluminum metal battery is either an aluminum symmetric battery or an aluminum metal full battery.

9. An aluminum metal battery according to claim 8, characterized in that, The positive electrode of the aluminum metal full cell is suitable for intercalation-type positive electrode materials in haloaluminate systems or other positive electrode materials.

Images