Electrolyte for improving stability of zinc metal negative electrode, preparation method and battery
By using a mixed electrolyte of zinc trifluoromethanesulfonate, γ-valerol, and propylcaprolactone in aqueous zinc batteries, the instability problem of zinc metal anodes was solved, improving battery cycle life and coulombic efficiency, and promoting the commercial application of zinc metal anodes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN UNIV
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-14
Smart Images
Figure CN121862902A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of aqueous zinc battery electrolytes, and more specifically, to an electrolyte for improving the stability of zinc metal negative electrodes, a preparation method thereof, and a battery. Background Technology
[0002] Aqueous zinc batteries are considered a promising large-scale energy storage system due to their high safety, low cost, and environmental friendliness. However, zinc metal anodes commonly suffer from uncontrolled dendrite growth, hydrogen evolution reaction, surface passivation, and corrosion during actual cycling, severely impacting cycle life, coulombic efficiency, and overall reversibility. These challenges primarily stem from the chemical and electrochemical instability at the zinc metal anode-electrolyte interface, hindering the further commercial application of aqueous zinc batteries. Therefore, designing efficient electrolyte additives to regulate zinc deposition behavior and stabilize the zinc metal anode-electrolyte interface has become a key approach to improving the stability of zinc metal anodes. Summary of the Invention
[0003] The purpose of this application is to provide an electrolyte and preparation method for improving the stability of zinc metal anode, and a battery, so as to regulate zinc deposition behavior, stabilize the zinc metal anode-electrolyte interface, and improve the stability of zinc metal anode.
[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide a method for preparing an electrolyte to improve the stability of a zinc metal anode, the method comprising: Step 1: Prepare a zinc trifluoromethanesulfonate electrolyte with a concentration of 1M-3M using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent. Step 2: Select γ-valerolactone and propylcaprolactone as additives and add them to the zinc trifluoromethanesulfonate electrolyte prepared in Step 1 to obtain a mixed electrolyte.
[0005] Secondly, embodiments of this application provide a zinc trifluoromethanesulfonate mixed electrolyte, which is a mixed electrolyte obtained by the above-described electrolyte preparation method for improving the stability of the zinc metal negative electrode.
[0006] Thirdly, embodiments of this application provide a battery comprising a negative electrode zinc metal sheet, a positive electrode metal sheet, and the aforementioned zinc trifluoromethanesulfonate mixed electrolyte.
[0007] Compared to existing technologies, this application provides an electrolyte and preparation method for improving the stability of a zinc metal anode, along with a battery. Zinc trifluoromethanesulfonate is used as the solute and deionized water as the solvent to prepare a 1M-3M zinc trifluoromethanesulfonate electrolyte. γ-valerol and propylcaprolactone are selected as additives and added to the prepared zinc trifluoromethanesulfonate electrolyte to obtain a mixed electrolyte. Based on this mixed electrolyte, zinc-zinc symmetric batteries and zinc-copper asymmetric batteries are assembled to evaluate its ability to improve the stability of the zinc metal anode. The selection of γ-valerol and propylcaprolactone electrolyte additives simultaneously regulates the deposition crystal orientation of the zinc metal anode and promotes the formation of the solid electrolyte interface, suppressing dendrite formation, hydrogen evolution, corrosion, etc., thereby improving the cycle life of symmetric batteries and stabilizing the coulombic efficiency of asymmetric batteries.
[0008] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0009] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0010] Figure 1 The graphs show the cycle performance of zinc-zinc symmetric batteries in Examples 1, 2, and 3.
[0011] Figure 2 The graphs show the cycle performance of zinc-zinc symmetric batteries in Examples 4, 5, and 6.
[0012] Figure 3 The graphs show the cycle performance of zinc-zinc symmetric batteries in Examples 7, 8, 9, 10, and 11.
[0013] Figure 4 The graphs show the cycle performance of zinc-zinc symmetric batteries in Examples 2, 5, and 9.
[0014] Figure 5 The graph shows the cycle performance of a low-current zinc-zinc symmetric battery in Example 9.
[0015] Figure 6 The graph shows the cycle performance of the low-current zinc-copper asymmetric battery in Example 9.
[0016] Figure 7 The image shows the XRD pattern of the zinc metal anode on the deposited side after cycling in Example 9, a zinc-zinc symmetric battery. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0018] To explore and improve the interfacial relationship between the zinc metal anode and the electrolyte, thereby enhancing the stability of the zinc metal anode, this application proposes a method for preparing an electrolyte to improve the stability of the zinc metal anode, comprising the following steps: Step 1: Prepare a zinc trifluoromethanesulfonate electrolyte with a concentration of 1M-3M using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent.
[0019] Step 2: Select γ-valerolactone and propylcaprolactone as additives and add them to the zinc trifluoromethanesulfonate electrolyte prepared in Step 1 to obtain a mixed electrolyte.
[0020] Glycaprolactone is insoluble in water, but when combined with zinc trifluoromethanesulfonate, it can be made soluble in water. Glycaprolactone is used to form a solid electrolyte interface, which greatly improves corrosion resistance, inhibits dendrite formation, and enhances interface stability.
[0021] In this embodiment of the invention, γ-valerolactone and propylcaprolactone are selected as electrolyte additives. At the same time, the deposition crystal orientation of the zinc metal anode is regulated and the formation of the solid electrolyte interface is promoted, inhibiting dendrites, hydrogen evolution, corrosion, etc., thereby improving the cycle life of symmetric cells and stabilizing the coulombic efficiency of asymmetric cells.
[0022] Optionally, in step 1, after mixing zinc trifluoromethanesulfonate and deionized water, the mixture is ultrasonically stirred until completely dissolved. Of course, other stirring methods can also be used; the advantage of ultrasonic stirring is that it results in a more uniform mixture.
[0023] Optionally, the zinc trifluoromethanesulfonate electrolyte is prepared at a concentration of 2M.
[0024] Optionally, after adding the additive to the zinc trifluoromethanesulfonate electrolyte prepared in step 1, ultrasonic stirring is performed for 30 minutes to promote dispersion and dissolution, so as to obtain a uniform mixed electrolyte.
[0025] Optionally, in step 2, the ratio of the total volume of additives to the volume of deionized water in the zinc trifluoromethanesulfonate electrolyte is 1:8 to 1:2.
[0026] Optionally, in step 2, the total volume ratio of the additives to the deionized water volume in the zinc trifluoromethanesulfonate electrolyte is 1:4.
[0027] The ratio of the total volume of the additive to the volume of deionized water in the zinc trifluoromethanesulfonate electrolyte can be 1:8, 1:4, or 1:2, with a preferred ratio of 1:4.
[0028] Optionally, the volume ratio of γ-valerolactone to propylcaprolactone is 1:4 to 4:1.
[0029] Optionally, the volume ratio of γ-valerolactone to propylcaprolactone is 1:1.
[0030] The volume ratio of the two additives can be 1:4, 2:3, 1:1, 3:2 and 4:1, preferably 1:1.
[0031] This invention also provides a zinc trifluoromethanesulfonate mixed electrolyte, which is a mixed electrolyte obtained by the above-described electrolyte preparation method for improving the stability of the zinc metal negative electrode.
[0032] This invention also provides a battery comprising a negative electrode zinc metal sheet, a positive electrode metal sheet, and the aforementioned zinc trifluoromethanesulfonate mixed electrolyte. The positive electrode metal sheet can be a zinc metal sheet or a copper metal sheet.
[0033] A zinc-zinc symmetric battery is composed of a zinc metal negative electrode, a zinc metal positive electrode, and a zinc trifluoromethanesulfonate mixed electrolyte. A zinc-copper asymmetric battery is composed of a zinc metal negative electrode, a copper metal positive electrode, and a zinc trifluoromethanesulfonate mixed electrolyte. By selecting γ-valerolactone and propylcaprolactone electrolyte additives, the deposition crystal orientation of the zinc metal negative electrode is simultaneously controlled, and the formation of the solid-state electrolyte interface is promoted, suppressing dendrite formation, hydrogen evolution, and corrosion, thereby improving the cycle life of the symmetric battery and stabilizing the coulombic efficiency of the asymmetric battery.
[0034] The zinc-zinc symmetric battery and zinc-copper asymmetric battery prepared in the embodiments of the present invention may be, but are not limited to, button cells.
[0035] The features and performance of this application will be further described in detail below with reference to the embodiments.
[0036] Example 1 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. γ-valerolactone was added as an additive, with a volume ratio of additive to deionized water of 1:8. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation A (1:8). Zinc-zinc symmetric batteries were assembled using electrolyte formulation A, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0037] Example 2 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. γ-valerolactone was added as an additive, with a volume ratio of additive to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation A (1:4). Zinc-zinc symmetric batteries were assembled using electrolyte formulation A, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0038] Example 3 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. γ-valerolactone was added as an additive, with a volume ratio of additive to deionized water of 1:2. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation A (1:2). Zinc-zinc symmetric batteries were assembled using electrolyte formulation A, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0039] Example 4 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Additive propylcaprolactone was added at a volume ratio of 1:8 to deionized water, and the mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation B (1:8). Zinc-zinc symmetric batteries were assembled using this electrolyte formulation B, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0040] Example 5 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Additive propylcaprolactone was added at a volume ratio of 1:4 to deionized water, and the mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation B (1:4). Zinc-zinc symmetric batteries were assembled using this electrolyte formulation B, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the battery exhibited superior cycle performance.
[0041] Example 6 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Additive gluconolactone was added at a volume ratio of 1:2 to deionized water, and the mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming electrolyte formulation B (1:2). Zinc-zinc symmetric batteries were assembled using this electrolyte formulation B, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0042] Example 7 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Simultaneously, additives γ-valerolactone and propylcaprolactone were added, with a volume ratio of γ-valerolactone to propylcaprolactone of 1:4 and a total additive volume ratio to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming a mixed additive formulation (1:4). A zinc-zinc symmetric battery was assembled using this zinc trifluoromethanesulfonate mixed electrolyte, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the battery exhibited superior cycle performance.
[0043] Example 8 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Simultaneously, additives γ-valerolactone and propylcaprolactone were added, with a volume ratio of γ-valerolactone to propylcaprolactone of 2:3 and a total additive volume ratio to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming a mixed additive formulation (2:3). A zinc-zinc symmetric battery was assembled using this zinc trifluoromethanesulfonate mixed electrolyte, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the battery exhibited superior cycle performance.
[0044] Example 9 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Simultaneously, additives γ-valerolactone and propylcaprolactone were added, with a volume ratio of γ-valerolactone to propylcaprolactone of 1:1 and a total additive volume ratio to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming a 1:1 mixed additive formulation. Zinc-zinc symmetric and zinc-copper asymmetric batteries were assembled using this zinc trifluoromethanesulfonate mixed electrolyte, zinc metal sheets, and copper metal sheets. Charge-discharge cycle tests were conducted, and the batteries exhibited superior cycle performance.
[0045] Example 10 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Simultaneously, additives γ-valerolactone and propylcaprolactone were added, with a volume ratio of γ-valerolactone to propylcaprolactone of 3:2 and a total additive volume ratio to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming a mixed additive formulation (3:2). A zinc-zinc symmetric battery was assembled using this zinc trifluoromethanesulfonate mixed electrolyte, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the battery exhibited superior cycle performance.
[0046] Example 11 Using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent, the mixed solute and solvent were weighed and sonicated until completely dissolved to prepare a 2 M zinc trifluoromethanesulfonate electrolyte. Simultaneously, additives γ-valerolactone and propylcaprolactone were added, with a volume ratio of γ-valerolactone to propylcaprolactone of 4:1 and a total additive volume ratio to deionized water of 1:4. The mixture was sonicated for 30 minutes to promote dispersion and dissolution, forming a mixed additive formulation (4:1). A zinc-zinc symmetric battery was assembled using this zinc trifluoromethanesulfonate mixed electrolyte, zinc metal sheets, and zinc metal sheets. Charge-discharge cycle tests were conducted, and the battery exhibited superior cycle performance.
[0047] The button cells (zinc-zinc symmetric) assembled in Examples 1-11 were subjected to constant current charge-discharge tests (5 mA cm⁻¹) at 30 °C. -2 5 mAh cm -2 The button cell (zinc-zinc symmetric) constructed in Example 9 was subjected to a low-current constant-current charge-discharge test (1 mA cm⁻¹). -2 1 mAh cm -2 The button cell (zinc-copper asymmetric) composed in Example 9 was subjected to a low-current constant-current charge-discharge test (1 mA cm⁻¹). -2 1 mAh cm -2 The discharge cutoff voltage is 0.5 V.
[0048] The button batteries constructed in Examples 1-11 were analyzed. Figure 1-2 The cycle performance diagram of the zinc-zinc symmetric battery shows that Examples 2 and 5 are superior in electrolyte formulations A and B, respectively, with only additives. This indicates that the preferred volume ratio of additive to deionized water is 1:4. Figure 3 The cycle performance diagram of the zinc-zinc symmetric battery shows that Example 9 is superior in the mixed additive formulation, indicating that the preferred volume ratio of additives γ-valerolactone and propylcaprolactone is 1:1. Figure 4The cycle performance of zinc-zinc symmetric cells using 2 M zinc trifluoromethanesulfonate and preferred single-additive formulations A, B, and mixed-additive formulations was compared at 5 mA cm⁻¹. -2 5 mAh cm -2 Under the specified conditions, the mixed additive formulation in Example 9 can achieve a cycle performance of 520 h, which is the optimal cycle performance. Figure 5 With a small current of 1 mA cm -2 1 mAh cm -2 Under the same conditions, the cycle performance of the zinc-zinc symmetric battery of 2 M zinc trifluoromethanesulfonate and the mixed additive formulation Example 9 was compared. The mixed additive formulation Example 9 achieved a cycle performance of 2738 h, which far exceeded that of 2 M zinc trifluoromethanesulfonate. Figure 6 With a small current of 1 mA cm -2 1 mAh cm -2 Under the same conditions, the cycle performance of 2 M zinc trifluoromethanesulfonate and zinc-copper asymmetric batteries of the mixed additive formulation Example 9 were compared. The mixed additive formulation Example 9 had an average coulombic efficiency of 99.4% after 1500 cycles, and its stability was much higher than that of 2 M zinc trifluoromethanesulfonate.
[0049] Further analysis and comparison were performed at a small current of 1 mA cm⁻¹ -2 1 mAh cm -2 Under certain conditions, the structural composition of the zinc metal anode on the deposited side after 100 h of cycling in a zinc-zinc symmetric cell. Figure 7 The diffraction peaks appearing at 5-20 degrees represent the basic salts of the byproducts, reflecting the significant side reactions of the zinc metal anode after cycling in the 2 M zinc trifluoromethanesulfonate electrolyte, which depleted the active zinc metal. In contrast, the zinc metal anode after cycling in Example 9 of the mixed additive formulation was relatively stable, and no byproducts were detected.
[0050] In summary, this application provides an electrolyte and preparation method for improving the stability of a zinc metal anode, along with a battery. Zinc trifluoromethanesulfonate is used as the solute and deionized water as the solvent to prepare a 1M-3M zinc trifluoromethanesulfonate electrolyte. γ-valerol and propanylcaprolactone are selected as additives and added to the prepared zinc trifluoromethanesulfonate electrolyte to obtain a mixed electrolyte. Based on this mixed electrolyte, zinc-zinc symmetric batteries and zinc-copper asymmetric batteries are assembled to evaluate its ability to improve the stability of the zinc metal anode. The selection of γ-valerol and propanylcaprolactone electrolyte additives simultaneously regulates the deposition crystal orientation of the zinc metal anode and promotes the formation of the solid electrolyte interface, inhibiting dendrite formation, hydrogen evolution, corrosion, etc., thereby improving the cycle life of the symmetric battery and stabilizing the coulombic efficiency of the asymmetric battery.
[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing an electrolyte to improve the stability of a zinc metal anode, characterized in that, The method includes: Step 1: Prepare a zinc trifluoromethanesulfonate electrolyte with a concentration of 1M-3M using zinc trifluoromethanesulfonate as the solute and deionized water as the solvent. Step 2: Select γ-valerolactone and propylcaprolactone as additives and add them to the zinc trifluoromethanesulfonate electrolyte prepared in Step 1 to obtain a mixed electrolyte.
2. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, In step 1, after mixing zinc trifluoromethanesulfonate and deionized water, the mixture is ultrasonically stirred until completely dissolved.
3. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, The concentration of the zinc trifluoromethanesulfonate electrolyte is 2M.
4. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, After adding the additive to the zinc trifluoromethanesulfonate electrolyte prepared in step 1, the mixture is ultrasonically stirred for 30 minutes.
5. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, In step 2, the ratio of the total volume of additives to the volume of deionized water in the zinc trifluoromethanesulfonate electrolyte is 1:8 to 1:
2.
6. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, In step 2, the total volume ratio of the additives to the deionized water volume in the zinc trifluoromethanesulfonate electrolyte is 1:
4.
7. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, The volume ratio of γ-valerolactone to propylcaprolactone is 1:4 to 4:
1.
8. The method for preparing an electrolyte to improve the stability of a zinc metal anode as described in claim 1, characterized in that, The volume ratio of γ-valerolactone to propylcaprolactone is 1:
1.
9. A zinc trifluoromethanesulfonate mixed electrolyte, characterized in that, The mixed electrolyte obtained by any one of the electrolyte preparation methods for improving the stability of zinc metal anodes according to claims 1-8.
10. A battery, characterized in that, The battery comprises a negative electrode zinc metal sheet, a positive electrode metal sheet, and the zinc trifluoromethanesulfonate mixed electrolyte as described in claim 9.