Water-based zinc ion battery electrolyte for promoting rapid activation and water-based zinc ion battery
By adding persulfate to the electrolyte of aqueous zinc-ion batteries, the problem of irreversible loss of active materials caused by manganese dissolution was solved, and rapid activation and long-term stability of the battery were achieved.
Patent Information
- Application Number
- CN202610054323.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-15
- Publication Date
- 2026-03-06
AI Technical Summary
Existing aqueous zinc-ion batteries suffer from a disruption of the manganese dissolution-deposition balance during charge-discharge cycles, leading to irreversible loss of active materials and affecting the battery's cycle life and capacity retention. Meanwhile, high concentrations of Mn2+ result in slow activation of the battery during the initial charge-discharge cycle.
Introducing persulfate as a functional additive into the electrolyte promotes the regeneration of failed active sites and the directional deposition of Mn2+ by directional adsorption onto the active sites of manganese oxide cathode, thereby repairing the active material and achieving rapid battery activation.
It significantly shortens the battery activation cycle, enabling the capacity to quickly reach its maximum stable value, and improves the battery's long-cycle stability and electrochemical performance.
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Figure CN121618077A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery electrolyte technology, specifically to an aqueous zinc-ion battery electrolyte and an aqueous zinc-ion battery that promotes rapid activation. Background Technology
[0002] The information disclosed in this background section is intended only to enhance some understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.
[0003] With the development of clean energy technologies such as wind, solar, and tidal power, large-scale energy storage technology has become increasingly important. In recent years, lithium-ion batteries have been widely used in portable electronic devices, electric vehicles, and large-scale energy storage due to their high energy density, long lifespan, and portability. However, limited lithium resources and demanding assembly conditions have increased the cost of commercial lithium-ion batteries. Meanwhile, compared to lithium-ion batteries based on organic electrolytes, aqueous metal-ion batteries, represented by aqueous zinc-ion batteries, offer higher safety and lower cost, demonstrating significant application potential in large-scale energy storage. Furthermore, the zinc anode has a high theoretical capacity and a low redox potential (-0.76V vs. standard hydrogen electrode). These characteristics make aqueous zinc-ion batteries promising for future large-scale energy storage applications.
[0004] Among numerous cathode materials, manganese-based oxides (such as MnO, MnO2, and Mn3O4) are considered promising cathode materials for aqueous zinc-ion batteries due to their abundant resources, low cost, high operating voltage, and large theoretical capacity. However, these materials suffer from a disruption of the manganese dissolution-deposition balance during charge-discharge cycles, leading to irreversible loss of active materials and severely limiting the battery's cycle life and capacity retention.
[0005] To suppress manganese dissolution at the cathode, existing technologies commonly employ the strategy of introducing manganese salts (such as MnSO4) into the electrolyte, thereby increasing the concentration of Mn in the electrolyte. 2+ Concentration is used to suppress the dissolution of manganese oxides using the law of mass action. However, while this strategy alleviates dissolution, it often leads to a slow activation process in the battery during the initial charge-discharge cycles. This is because high concentrations of Mn... 2+ It will competitively adsorb onto the positive electrode active site and may form insulating byproducts, hindering Zn adsorption. 2+ The insertion / extraction of the electrode material and the full activation of the electrode material mean that the battery capacity needs to undergo a long cycle period to slowly reach its peak, which affects the rapid manifestation of its comprehensive electrochemical performance.
[0006] Therefore, developing an electrolyte strategy that can effectively suppress manganese dissolution and promote rapid battery activation is of great significance for promoting the practical application of aqueous zinc-ion batteries. Summary of the Invention
[0007] Therefore, this invention aims to provide an optimized solution, proposing an aqueous zinc-ion battery electrolyte and a corresponding aqueous zinc-ion battery. The electrolyte of this invention incorporates persulfate as a functional additive. This persulfate acts as an electron mediator for divalent manganese ions, directionally adsorbing onto the surface of the active sites on the manganese oxide cathode, promoting the regeneration of failed active sites in the manganese-based cathode material, and inducing manganese ions in the electrolyte to repair and replenish the active material, accelerating the battery activation process in the initial stage and enabling the capacity to rapidly reach its highest stable value.
[0008] The technical solution adopted in this invention is as follows: In a first aspect, the present invention provides an aqueous zinc-ion battery electrolyte that promotes rapid activation, comprising an aqueous solvent, a soluble zinc salt, a soluble manganese salt, and a persulfate additive; wherein the molar concentration of the persulfate additive is from 0.001 mol / L to 0.5 mol / L, and the molar concentration of the soluble manganese salt is from 0.01 mol / L to 3 mol / L.
[0009] Preferably, the persulfate is one or more of lithium persulfate, sodium persulfate, potassium persulfate, and ammonium persulfate.
[0010] More preferably, the persulfate is sodium persulfate.
[0011] Preferably, the molar concentration of the persulfate is 0.05 mol / L.
[0012] Preferably, the soluble zinc salt is one or more of zinc sulfate, zinc acetate, zinc chloride, zinc trifluoromethanesulfonate, and zinc perchlorate.
[0013] Preferably, the molar concentration of the soluble zinc salt is from 0.01 mol / L to 5 mol / L.
[0014] Preferably, the soluble manganese salt is one or more of manganese sulfate, manganese carbonate, manganese acetate, manganese chloride, and manganese nitrate.
[0015] Secondly, the present invention provides a method for preparing the aqueous zinc-ion battery electrolyte that promotes rapid activation, comprising: dissolving the soluble zinc salt, soluble manganese salt and persulfate additive in an aqueous solvent and mixing them evenly.
[0016] Thirdly, an aqueous zinc-ion battery is provided, comprising: The positive electrode contains manganese oxide active material; The negative electrode contains metallic zinc or a zinc alloy; Diaphragm; And the aqueous zinc-ion battery electrolyte that promotes rapid activation as described in the first aspect.
[0017] Preferably, the positive electrode is one or more of manganese monoxide, manganese dioxide, manganese trioxide, and manganese tetroxide; or, it is a composite material of the above-mentioned manganese oxide and carbon material, wherein the carbon material includes, but is not limited to, one or more of graphene, carbon nanotubes, carbon nanofibers, or activated carbon.
[0018] Fourthly, the present invention provides a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Preparation of positive electrode sheet: The positive electrode material, graphite, acetylene black and binder are thoroughly mixed. The resulting slurry is evenly coated onto the stainless steel mesh current collector with a scraper. After drying and pressing, the positive electrode sheet can be obtained. (2) Assemble the negative electrode shell, negative zinc sheet, separator, aqueous zinc-ion battery electrolyte of the present invention, positive electrode sheet, gasket, spring sheet and positive electrode shell in that order to obtain an aqueous zinc-ion battery.
[0019] Preferably, in step (1), the adhesive includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, etc.
[0020] Preferably, in step (1), the mass ratio of the positive electrode material, acetylene black, graphite and binder is 70~95:0~10:0~10:5~10.
[0021] Preferably, in step (1), the coating thickness of the slurry is 5~50 μm.
[0022] Preferably, in step (1), the drying temperature is 35~95 ℃ and the time is 2~24 h.
[0023] Preferably, in step (2), the thickness of the zinc sheet negative electrode is 10~500 μm.
[0024] Preferably, in step (2), the material of the diaphragm includes at least one of glass fiber, polypropylene, non-woven fabric, etc.
[0025] Compared with the related technologies known to the inventors, one of the technical solutions of the present invention has the following beneficial effects: This invention cleverly resolves the contradiction between "inhibiting dissolution" and "rapid activation" by introducing a specific concentration of persulfate additive into a conventional manganese salt electrolyte. Its synergistic mechanism is mainly reflected in the following three points: Promote the regeneration of deactivated sites: Persulfate ions can selectively adsorb onto active sites on the surface of manganese oxide cathodes. As a highly efficient electronic mediator, it promotes the electrochemical oxidation and regeneration of deactivated manganese sites during cycling (such as sites covered by low-valence manganese species or with structural distortions), thereby restoring their reactivity.
[0026] Induced directed deposition remediation: The adsorption energy of persulfate can alter the properties of the cathode / electrolyte interface, inducing Mn in the electrolyte. 2+ Ions preferentially and orderly deposit on the surface of the positive electrode active material, forming electrochemically active manganese oxides, thereby repairing and replenishing the active material dissolved and lost during the cycle in situ.
[0027] The aforementioned synergistic effect enables the battery to quickly establish a stable cathode / electrolyte interface and activate a large number of active sites in the early stages of cycling, significantly shortening the activation cycle for capacity ramp-up. This allows the battery specific capacity to quickly reach and maintain its highest stable value. At the same time, through continuous "dissolution-repair" dynamic balance, it effectively improves long-cycle stability. Attached Figure Description
[0028] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0029] Figure 1 The graph shows the cyclic test results of the zinc-ion batteries assembled in Example 1 and Comparative Example 1 at a current density of 0.2 A / g.
[0030] Figure 2 The charge-discharge curves of the zinc-ion batteries assembled for Example 2 and Comparative Example 2 during the second cycle at a current density of 0.2 A / g.
[0031] Figure 3 Charge-discharge curves of the zinc-ion batteries assembled for Example 3 and Comparative Example 3 after 15 cycles at a current density of 0.2 A / g.
[0032] Figure 4 Cycling curves of zinc-ion batteries assembled in Example 4 and Comparative Example 4 at a high current density of 2.0 A / g.
[0033] Figure 5 Cycling curves of zinc-ion batteries assembled in Examples 1, 5, and 6 at a current density of 0.2 A / g.
[0034] Figure 6 Cycling curves of zinc-ion batteries assembled in Example 1 and Comparative Example 7 at a current density of 0.2 A / g.
[0035] Figure 7Cycling curves of zinc-ion batteries assembled in Example 1 and Comparative Example 8 at a current density of 0.2 A / g.
[0036] Figure 8 Cycling curves of zinc-ion batteries assembled in Examples 1, 9, and 10 at a current density of 0.2 A / g. Detailed Implementation
[0037] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0038] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.
[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0040] Example 1: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: Add 2 mol of zinc sulfate, 0.2 mol of manganese sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, and stir thoroughly to obtain the target electrolyte.
[0041] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0042] The aqueous zinc-ion battery of this embodiment was subjected to constant current charge-discharge cycle testing at a current density of 0.2 A / g, and the results are shown in... Figure 1 The results showed that in Example 1, after introducing sodium persulfate into the electrolyte system, a high specific capacity of 314.4 mA h / g was achieved after only 15 initial activation cycles, and a stable output with no decay was achieved after 160 long-term cycles.
[0043] Comparative Example 1: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate and 0.2 mol of manganese sulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0044] (2) An aqueous zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested. This embodiment is a comparative example of Embodiment 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 1 The results showed that without the introduction of sodium persulfate, the aqueous zinc-ion battery exhibited slow initial activation kinetics, with the activation cycle significantly prolonged to over 120 cycles. After 15 cycles, the specific capacity reached only 242.8 mA h / g, a value far lower than that of Example 1. Furthermore, this battery showed significant capacity decay after 120 cycles, failing to achieve stable output, a stark contrast to the performance of Example 1, which showed no capacity decay after 160 cycles.
[0045] Example 2: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 3 mol of zinc sulfate, 1 mol of manganese sulfate and 0.05 mol of potassium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0046] (2) A water-based zinc-ion battery was assembled using manganese dioxide / carbon nanotube composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and the electrochemical performance was tested.
[0047] The charge-discharge curve of the aqueous zinc-ion battery in this embodiment at a current density of 0.2 A / g in the second cycle is shown below. Figure 2 The results showed that the battery with potassium persulfate introduced exhibited a significant increase in charge-discharge specific capacity during the second cycle. This directly confirms that the introduction of potassium persulfate can exert a capacity-gain effect in the early stages of battery cycling, laying the foundation for efficient utilization of active materials and capacity stability in subsequent cycles.
[0048] Comparative Example 2: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 3 mol of zinc sulfate and 1 mol of manganese sulfate to 1 L of pure water and stir thoroughly to obtain the target electrolyte.
[0049] (2) A water-based zinc-ion battery was assembled using manganese dioxide / carbon nanotube composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and the electrochemical performance was tested.
[0050] This embodiment is a comparative example of Embodiment 2 above. The charge-discharge curve of the aqueous zinc-ion battery of this comparative example at a current density of 0.2 A / g in the second cycle is shown below. Figure 2 The results showed that the specific capacity of Comparative Example 2 was lower than that of Example 2 in the second charge-discharge cycle, indicating that its specific capacity increased more slowly, further confirming the slow initial cycle activation process.
[0051] Example 3: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 3 mol of zinc sulfate, 1 mol of manganese carbonate and 0.05 mol of ammonium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0052] (2) A water-based zinc-ion battery was assembled using manganese oxide / graphene composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and non-woven fabric as the separator, and its electrochemical performance was tested.
[0053] The charge-discharge curves of the aqueous zinc-ion battery in this embodiment at a current density of 0.2 A / g on the 15th cycle are shown below. Figure 3 The results showed that the battery's charge and discharge capacity significantly improved during this cycle. This phenomenon stems from the continuous regulatory effect of persulfate on the positive electrode reaction system, which efficiently mediates the Mn content in the electrolyte. 2+ The directional oxidation-deposition process promotes the dynamic replenishment of active materials in the cycle, ultimately resulting in a significant increase in charge and discharge capacity.
[0054] Comparative Example 3: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 3 mol of zinc sulfate and 1 mol of manganese carbonate to 1 L of pure water and stir thoroughly to obtain the target electrolyte.
[0055] (2) A water-based zinc-ion battery was assembled using manganese oxide / graphene composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and non-woven fabric as the separator, and its electrochemical performance was tested.
[0056] This example is a comparative example of Example 3 above. The charge-discharge curve of the aqueous zinc-ion battery of this comparative example at a current density of 0.2 A / g on the 15th cycle is shown below. Figure 3The results showed that the specific capacity of the battery without added ammonium persulfate was still significantly lower than that of Example 3, even after a longer initial cycle, further confirming the important role of 0.05 mol of ammonium persulfate in the initial cycle activation.
[0057] Example 4: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc trifluoromethanesulfonate, 0.5 mol of manganese sulfate and 0.1 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0058] (2) A water-based zinc-ion battery was assembled using manganese dioxide / carbon nanofiber composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and the electrochemical performance was tested.
[0059] The aqueous zinc-ion battery of this embodiment was subjected to constant current charge-discharge cycle testing at a current density of 2.0 A / g, and the results are shown in... Figure 4 The results showed that the battery's specific capacity was significantly higher than 50 mAh / g, and the cycling curve exhibited excellent stability, maintaining a high initial specific capacity value even after 4000 cycles.
[0060] Comparative Example 4: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc trifluoromethanesulfonate and 0.5 mol of manganese sulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0061] (2) A water-based zinc-ion battery was assembled using manganese dioxide / carbon nanofiber composite material as the positive electrode, a 200 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and the electrochemical performance was tested.
[0062] This embodiment is a comparative example of Embodiment 4 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 2.0 A / g. The results are shown below. Figure 4 It is evident that in batteries without 0.1 mol of sodium persulfate, the discharge specific capacity is less than 50 mAh / g, and the specific capacity continues to decrease during cycling. Furthermore, the battery fails after 3000 cycles and cannot continue cycling.
[0063] Example 5: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc trifluoromethanesulfonate, 0.2 mol of manganese sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0064] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0065] The aqueous zinc-ion battery in Example 5 was subjected to constant current charge-discharge cycle testing at a current density of 1.0 A / g. The results showed that after 1000 consecutive cycles at a relatively high current density, the battery maintained 100% capacity, achieving stable output with no capacity decay over long-term cycling.
[0066] Example 6: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc chloride, 0.2 mol of manganese sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0067] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0068] The aqueous zinc-ion battery in Example 6 was subjected to constant current charge-discharge cycle testing at a current density of 2.0 A / g. It showed that even at a high current density of 2.0 A / g, it could still maintain a stable discharge capacity of 114.1 mA h / g, demonstrating excellent high current stability.
[0069] Example 7: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese chloride and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0070] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0071] The aqueous zinc-ion battery in Example 7 was subjected to constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results showed that after introducing 0.05 mol of sodium persulfate as an additive, the initial activation cycle was shortened to less than 25 cycles, and stable output with no capacity decay was achieved after 180 cycles.
[0072] Example 8: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese nitrate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0073] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0074] The aqueous zinc-ion battery in Example 8 was subjected to constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results showed that after introducing 0.05 mol of sodium persulfate as an additive, the initial activation cycle was shortened to less than 22 cycles, and stable output with no capacity decay was achieved after 150 cycles.
[0075] Example 9: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese carbonate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0076] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0077] The aqueous zinc-ion battery in Example 9 was subjected to constant current charge-discharge cycle testing at a current density of 1.0 A / g. The results showed that after introducing sodium persulfate as an additive, the initial activation cycle was shortened to less than 25 cycles, and stable output with no capacity decay was achieved after 1000 cycles.
[0078] Example 10: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese acetate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0079] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0080] The aqueous zinc-ion battery of Example 10 was subjected to constant current charge-discharge cycle testing at a current density of 1.0 A / g. The results showed that after introducing sodium persulfate as an additive, the initial activation cycle was shortened to less than 23 cycles, and stable output with no capacity decay was achieved after 3000 cycles.
[0081] Comparative Example 5: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese sulfate and 0.0005 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0082] (2) An aqueous zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested. This embodiment is a comparative example of Example 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 5 The test results showed that the system only exhibited a weak activation-promoting effect, far less than the significant improvement in Example 1, indicating that the addition of persulfate needs to reach a specific "critical concentration" in order to effectively exert its function as an electronic mediator and induce deposition.
[0083] Comparative Example 6: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese sulfate and 0.6 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0084] (2) An aqueous zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested. This embodiment is a comparative example of Example 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 5 The test results showed that the system exhibited low coulombic efficiency and a sharp decline in cycle stability, indicating that there is an upper limit to the concentration of persulfate added; exceeding this limit will lead to rapid degradation of battery performance.
[0085] Comparative Example 7: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.2 mol of manganese sulfate and 0.05 mol of hydrogen peroxide to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0086] (2) An aqueous zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested. This embodiment is a comparative example of Embodiment 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 6 The results showed deterioration in battery performance, side reactions, and uncontrolled deposition. This indicates that not all oxidants can achieve good electrochemical stability, and the role of persulfate is unique.
[0087] Comparative Example 8: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0088] (2) An aqueous zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested. This embodiment is a comparative example of Embodiment 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 7 In the middle. Due to the lack of Mn available for "induced deposition". 2+ The source of the problem is that persulfate additives cannot replenish or repair the active materials. The oxidation caused by persulfate leads to damage to the positive electrode structure or corrosion of the zinc negative electrode, resulting in poor cycle performance. This underscores the importance of the premise in this invention: "adding persulfate to an electrolyte containing existing manganese salts."
[0089] Comparative Example 9: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 0.005 mol of manganese sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0090] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0091] This embodiment is a comparative example of Embodiment 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 8 The result is Mn 2+ Insufficient manganese source limits the "repair" effect of persulfate, leading to a severe decline in battery specific capacity and cycle performance, highlighting the importance of a certain concentration of manganese salt.
[0092] Comparative Example 10: An aqueous zinc-ion battery electrolyte and a method for preparing an aqueous zinc-ion battery, comprising the following steps: (1) Add 2 mol of zinc sulfate, 3 mol of manganese sulfate and 0.05 mol of sodium persulfate to 1 L of pure water, stir thoroughly to obtain the target electrolyte.
[0093] (2) A water-based zinc-ion battery was assembled using manganese oxide quantum dot / graphene composite material as the positive electrode, a 100 μm thick zinc sheet as the negative electrode, and glass fiber as the separator, and its electrochemical performance was tested.
[0094] This embodiment is a comparative example of Embodiment 1 above. The aqueous zinc-ion battery of this comparative example underwent constant current charge-discharge cycle testing at a current density of 0.2 A / g. The results are shown below. Figure 8 The results showed high Mn levels. 2+ The concentration itself strongly inhibits activation, and even with the addition of persulfate, its effect of promoting activation is partially offset, but it is still better than the case where no persulfate is added.
[0095] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A water-based zinc-ion battery electrolyte that promotes fast activation, characterized in that, The water-based electrolyte for promoting rapid activation of a zinc ion battery comprises a water solvent, a soluble zinc salt, a soluble manganese salt and a persulfate additive; wherein the molar concentration of the persulfate additive is 0.001 mol / L to 0.5 mol / L, and the molar concentration of the soluble manganese salt is 0.01 mol / L to 3 mol / L.
2. The water-based zinc-ion battery electrolyte facilitating fast activation of claim 1, wherein, The persulfate salt is one or more of lithium persulfate, sodium persulfate, potassium persulfate and ammonium persulfate.
3. The water-based zinc-ion battery electrolyte facilitating fast activation of claim 2, wherein, The persulfate salt is sodium persulfate, and the molar concentration of the persulfate salt is 0.05 mol / L.
4. The water-based zinc-ion battery electrolyte facilitating fast activation of claim 1, wherein, The soluble zinc salt is one or more of zinc sulfate, zinc acetate, zinc chloride, zinc triflate and zinc perchlorate. The molar concentration of the soluble zinc salt is 0.01 mol / L to 5 mol / L. The soluble manganese salt is one or more of manganese sulfate, manganese carbonate, manganese acetate, manganese chloride and manganese nitrate.
5. The method for preparing the electrolyte for a rapid activation-promoted aqueous zinc ion battery according to any one of claims 1 to 4, characterized in that, The water-based electrolyte for promoting rapid activation of a zinc ion battery comprises: The soluble zinc salt, the soluble manganese salt and the persulfate additive are dissolved in the water solvent and uniformly mixed.
6. A water-based zinc ion battery, characterized in that it comprises: a positive electrode comprising a manganese oxide active material; a negative electrode comprising metallic zinc or a zinc alloy; a separator; and the water-based electrolyte for promoting rapid activation of a zinc ion battery of any one of claims 1-4.
7. The aqueous zinc ion battery of claim 6, wherein the zinc metal is in the form of a zinc foil. The positive electrode is one or more of manganous oxide, manganese dioxide, dimanganese trioxide and trimanganese tetraoxide; or a composite material of the above manganese oxide and a carbon material, wherein the carbon material is one or more of graphene, carbon nanotubes, carbon nanofibers and activated carbon.
8. A method of preparing an aqueous zinc-ion battery, characterized in that, The water-based electrolyte for promoting rapid activation of a zinc ion battery comprises the following steps: (1) preparing a positive electrode sheet: the positive electrode material, graphite, acetylene black and a binder in claim 6 are thoroughly mixed, the obtained slurry is uniformly coated on a stainless steel mesh current collector by a doctor blade, and the positive electrode sheet is obtained after drying and pressing; (2) assembling in the order of a negative electrode shell, a zinc sheet negative electrode, a separator, the water-based electrolyte for promoting rapid activation of a zinc ion battery, the above positive electrode sheet, a gasket, a spring and a positive electrode shell, to obtain the water-based zinc ion battery.
9. The preparation method of the water-based zinc ion battery of claim 8, characterized in that: In step (1), the binder is at least one of polytetrafluoroethylene and polyvinylidene fluoride; In step (1), the mass ratio of the positive electrode material, acetylene black, graphite and binder is 70-95:0-10:0-10:5-10; In step (1), the coating thickness of the slurry is 5-50 μm; In step (1), the drying temperature is 35-95 ℃, and the drying time is 2-24 h.
10. The method for preparing a water-based zinc ion battery according to claim 8, characterized in that, In step (2), the thickness of the zinc sheet negative electrode is 10-500 μm; In step (2), the material of the separator is at least one of glass fiber, polypropylene and non-woven fabric.