Aqueous zinc ion battery electrolyte and aqueous zinc ion battery

Abstract

This invention discloses an aqueous zinc-ion battery electrolyte and an aqueous zinc-ion battery. The aqueous zinc-ion battery electrolyte uses zinc trifluoromethanesulfonate as the electrolyte, amlodipine benzenesulfonate as an additive, and an ethanol-water mixture as the solvent. Utilizing amlodipine benzenesulfonate as an interface modifier, it effectively protects the zinc anode, suppresses interfacial side reactions, induces uniform zinc deposition, and improves the initial capacity and cycle stability of the aqueous zinc-ion battery. The aqueous zinc-ion battery electrolyte of this invention enables zinc-zinc symmetric batteries to achieve stable cycling for over 4400 hours. With ammonium vanadate as the cathode material, the capacity retention rate is 91.0% after 1000 cycles, solving the problem of poor battery cycle life caused by the interface challenges of the zinc electrode.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, and more specifically, to an aqueous battery electrolyte and an aqueous zinc-ion battery. Background Technology

[0002] Aqueous zinc-ion batteries have broad application prospects in large-scale and distributed energy storage due to their advantages such as high safety, ease of assembly, low cost, environmental friendliness, and high specific capacity of zinc metal anodes. However, the practical application of existing aqueous zinc-ion batteries is still constrained by the following: First, zinc dendrite growth and uneven electric field distribution lead to zinc deposition, which can easily puncture the separator and cause short circuits; second, severe side reactions occur because the zinc anode in aqueous electrolytes is thermodynamically unstable and prone to hydrogen evolution reactions, resulting in a decrease in coulombic efficiency. These problems seriously restrict the commercial application of zinc-ion batteries in the field of large-scale energy storage.

[0003] Currently, modifying the electrolyte is an effective way to suppress interfacial side reactions and induce uniform zinc deposition. As the ion transport medium connecting the zinc anode and cathode, the electrolyte's solvent composition, salt concentration, and additive type directly determine the solvation structure of zinc ions, interfacial mass transfer kinetics, and deposition behavior on the electrode surface. Targeted modification methods can fundamentally regulate the physicochemical properties of the electrode-electrolyte interface, solving the interfacial challenges of the zinc anode. Using electrolyte additives is a common approach to improve the zinc anode interface. For example, CN114725537A discloses an aqueous zinc-ion battery electrolyte that can suppress zinc dendrites and side reactions, and its application. This electrolyte, containing tripropylene glycol and propylene glycol additives, effectively improves the reversibility of the metallic zinc anode and reduces the occurrence of battery side reactions. CN114824511A discloses an organic salt for use as an electrolyte in an aqueous zinc-ion battery, which can suppress dendrite formation and corrosion side reactions. This discloses the use of sodium tartrate or sodium citrate as an electrolyte additive. The organic salt additive can be adsorbed onto the zinc surface in the electrolyte, improving the interfacial environment between the zinc anode and the electrolyte, disrupting the original solvation shell of zinc ions, thereby suppressing dendrite formation and corrosion side reactions, ultimately extending the lifespan of the aqueous zinc-ion battery and improving cycle stability. CN118800980A discloses a novel aqueous zinc-ion battery electrolyte additive and its application, using tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate as additives. These additives have abundant oxygen-containing groups on their surface, which facilitates the in-situ formation of a zinc-loving layer containing silicon oxides at the zinc anode, promoting uniform deposition of zinc ions on the zinc anode surface, thereby effectively suppressing the formation and excessive growth of zinc dendrites; and can also modify the Zn... 2+The solvation chemistry suppresses water-induced side reactions and reduces the activity of free water in the electrolyte. However, the regulatory effects of the electrolyte additives such as alcohols, organic salts, or silicon oxides are relatively singular, resulting in poor interfacial protective layer stability, high ion transport impedance, and an inability to simultaneously address both side reactions and regulate uniform deposition. Summary of the Invention

[0004] The main technical problem to be solved by this invention is to address the interface challenges of zinc anodes and the resulting rapid dendrite formation and poor cycle life, and to provide an aqueous battery electrolyte.

[0005] The objective of this invention is achieved through the following technical solution: An aqueous zinc-ion battery electrolyte comprises an electrolyte, an additive, and a solvent. The electrolyte is a soluble zinc salt, and the additive is amlodipine besylate. The concentration of the electrolyte is 0.5–3 mol / L, and the concentration of the additive is 0.02–0.16 mmol / L. This invention utilizes amlodipine besylate as an electrolyte additive, leveraging its various functional groups, such as amino groups, ether bonds, and dihydropyridine rings, to regulate the negative electrode-electrolyte interface performance, reduce system kinetic losses, maintain good electrolyte stability, and improve conductivity.

[0006] Furthermore, the soluble zinc salt includes one or more of zinc sulfate, zinc chloride, zinc bromide, zinc nitrate, zinc acetate, and zinc trifluoromethanesulfonate.

[0007] Furthermore, the solvent is an ethanol-water mixture, with a volume ratio of ethanol to water of 1:2 to 4.

[0008] Preferably, the aqueous zinc-ion battery electrolyte comprises a zinc trifluoromethanesulfonate, amlodipine benzenesulfonate, and an ethanol-water mixture, wherein the molar concentration of zinc trifluoromethanesulfonate is 2 mol / L, the concentration of amlodipine benzenesulfonate is 0.04 mmol / L, and the volume ratio of ethanol to water is 1:3.

[0009] Furthermore, the preparation steps of the aqueous zinc-ion battery electrolyte include: first dissolving the electrolyte in a solvent to obtain a mixed solution, and then adding additives to the mixed solution and stirring evenly to obtain the electrolyte.

[0010] Furthermore, the stirring time is 12~24h.

[0011] An aqueous zinc-ion battery includes a positive electrode, a negative electrode, and the aforementioned aqueous zinc-ion battery electrolyte.

[0012] Furthermore, the positive electrode material is one of vanadium-based materials, manganese-based materials, or Prussian blue compounds, and the negative electrode material is zinc material.

[0013] Furthermore, the cathode material includes vanadium-based materials, acetylene black, and a binder.

[0014] Furthermore, the vanadium-based material includes at least one of sodium vanadate, ammonium vanadate, or vanadium dioxide.

[0015] Furthermore, the mass ratio of the vanadium-based material, acetylene black, and binder is 7:2:1.

[0016] Compared with existing technologies, the beneficial effects are: This invention utilizes amlodipine besylate as a multifunctional electrolyte additive. Amlodipine besylate contains zinc-loving and hydrophobic functional groups. Due to its unique amino and dihydropyridine ring functional groups, amlodipine besylate is stably adsorbed onto the zinc surface. The hydrophobic benzene ring, chlorine atom, and alkyl chain structure form a water-depleted electric double layer (EDL) structure. Amlodipine besylate creates a zinc-loving and hydrophobic interfacial environment on the zinc surface. This water-depleted EDL structure inhibits the hydrogen evolution reaction and can modulate the Zn... 2+ The deposition behavior isolates the zinc anode from the desolvation process, suppresses the generation of side reactions, and induces uniform deposition. This invention also uses ethanol-water as a solvent, replacing some water with ethanol, which has a low dielectric constant. This enhances cation-anion interactions and promotes in-situ formation of a solid electrolyte interphase (SEI). Furthermore, ethanol can replace a certain amount of water molecules on the zinc surface, effectively reducing the number of active water molecules, decreasing the water activity at the electrolyte-electrode interface, increasing the solubility of amlodipine besylate, and accelerating the construction of a water-poor double-layer structure.

[0017] This invention uses amlodipine benzylsulfonate as a multifunctional electrolyte additive in an aqueous battery electrolyte at 1 mA cm⁻¹ 2 Current density, 1mAh cm 2 With its areal capacity, it can cycle stably for over 4400 hours. Using ammonium vanadate as the cathode material, this novel electrolyte achieves stable cycling at 5Ag... 1 After 1000 cycles, the capacity retention rate is 91.0%, demonstrating stable cycle performance and an ultra-long service life. Attached Figure Description

[0018] Figure 1 The ionic conductivity diagrams are for the electrolytes of Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2. Figure 2 The graphs show the performance of the full battery described in Example 1, Comparative Example 1, and Comparative Example 2. Figure 3 For 1mA cm 2 1mAh cm 2 Coulombic efficiency diagrams of Zn / / Cu half-cells in Example 1, Comparative Example 1, and Comparative Example 2 at current densities; Figure 4 CA curves of Zn / / Zn symmetric cells prepared in different electrolytes in Example 1 and Comparative Example 2; Figure 5 The zinc-zinc symmetric cells of Examples 1, 2, 3, 4, Comparative Example 1, and Comparative Example 2 were tested at 1 mA cm⁻¹. 2 Current density, 1mAh cm 2 Long-cycle voltage-time curves under area capacity; Figure 6 Examples 1, 1, and 2 were measured at 3 mA cm. 2 The current density, 1 mAh cm⁻¹ 2 Long-cycle voltage-time curves under area capacity; Figure 7 The zinc-zinc symmetric cells of Examples 1, 1, and 2 are used at 4 mA cm⁻¹. 2 The current density is 4 mAh / cm³. 2 Long-cycle voltage-time curves under area capacity; Figure 8 Examples 1, 1, and 2 are shown to have an areal capacity of 1 mAh cm⁻¹ under different current densities. 2 A comparison chart of rate performance; Figure 9 The full cells of Example 1, Comparative Example 1, and Comparative Example 2 are used at a current density of 1 A g. 1 2 A g 1 3 A g 1 4 A g 1 5A g 1 A comparison chart of rate performance; Figure 10 Zn / / NH4V4O is from Example 1 and Comparative Example 2. 10 The CV curve; Detailed Implementation The following examples further explain and clarify the invention, but the specific examples do not limit the invention in any way.

[0019] Example 1 This embodiment provides a method for preparing an aqueous zinc-ion battery electrolyte, the steps of which include: S1. At room temperature, 7.27 g of zinc trifluoromethanesulfonate was dissolved in 10 mL of a mixed solution of ethanol and deionized water, wherein the volume ratio of ethanol to deionized water was 1:3, to obtain an aqueous solution of zinc trifluoromethanesulfonate in ethanol.

[0020] S2. Amlodipine besylate (BHSA C) 26 H 31 ClN2O8S) was dissolved in S1, and the concentration of amlodipine benzylsulfonate was controlled at 0.04 mmol / L. The mixed solution was stirred for 12 h to obtain an aqueous zinc-ion battery electrolyte.

[0021] In other embodiments, the volume ratio of ethanol to deionized water in the ethanol-deionized water mixed solution can also be 1:2 or 1:4, and stirring the mixed solution for 24 hours can also achieve the purpose of the invention.

[0022] Example 2 This embodiment provides a method for preparing an aqueous zinc-ion battery electrolyte, the steps of which are the same as in Example 1, except that the concentration of amlodipine benzylsulfonate in the electrolyte is 0.02 mmol / L.

[0023] Example 3 This embodiment provides a method for preparing an aqueous zinc-ion battery electrolyte, the steps of which are the same as in Example 1, except that the concentration of amlodipine benzylsulfonate in the electrolyte is 0.08 mmol / L.

[0024] Example 4 This embodiment provides a method for preparing an aqueous battery electrolyte, the steps of which are the same as in Example 1, except that the concentration of amlodipine benzylsulfonate in the electrolyte is 0.16 mmol / L.

[0025] Comparative Example 1 This comparative example provides a method for preparing an aqueous battery electrolyte, the steps of which are as follows: at room temperature, 7.27 g of zinc trifluoromethanesulfonate is dissolved in 10 mL of deionized water, and the mixed solution is stirred for 12 h to obtain the electrolyte.

[0026] Comparative Example 2 This comparative example provides a method for preparing an aqueous battery electrolyte, comprising the following steps: at room temperature, 7.27 g of zinc trifluoromethanesulfonate is dissolved in 10 mL of a mixed solution of ethanol and deionized water, wherein the ratio of ethanol to deionized water is 1:3, and the mixed solution is stirred for 12 h to obtain the electrolyte.

[0027] (1) The ionic conductivity of the electrolytes in the examples and comparative examples was tested, such as... Figure 1 The results show that introducing an appropriate amount of amlodipine besylate into the electrolyte alleviated the decrease in ionic conductivity to some extent. Furthermore, the concentration of the additive had a significant impact on conductivity; compared to the ionic conductivity of Example 2 (0.02 mmol / L) and Example 3 (0.08 mmol / L), Example 1 (0.04 mmol / L) exhibited the highest ionic conductivity. This indicates that the optimal concentration of the additive amlodipine besylate is that of Example 1 (0.04 mmol / L), and introducing the optimal concentration of the additive is more conducive to constructing a highly efficient ion transport channel.

[0028] (2) Full cells were assembled for Examples 1, 1, and 2, with ammonium vanadate selected as the positive electrode material. The amlodipine benzenesulfonate additive imparted higher specific capacity and better charge transfer capability to the full cells, thus contributing to better electrochemical performance. The anode-electrolyte interface layer composed of amlodipine benzenesulfonate significantly suppressed water-induced side reactions, making the anode-electrolyte interface more stable. Full cells containing amlodipine benzenesulfonate in the electrolyte exhibited better long-cycle performance. Specifically, as follows... Figure 2 As shown, the battery containing amlodipine besylate at 5.0 A g 1 It still retains 211.8 mAh g after 1000 cycles. 1 The capacity of Example 1 corresponds to a capacity retention of 91.0%, with a coulombic efficiency close to 100%. In contrast, the full cell assembled in Comparative Example 2 exhibited severe capacity decay in the first 1000 cycles. After 5000 cycles, the capacity retention of Example 1 was still as high as 61.3%, higher than the capacity retention of 57.1% in Comparative Example 1. This indicates that the presence of amlodipine benzylsulfonate suppressed the capacity decay of the full cell.

[0029] (3) The coulombic efficiency of the Zn / / Cu half-cells assembled in Example 1, Comparative Example 1, and Comparative Example 2 was tested to effectively evaluate the Zn efficiency. 2+ Reversibility of deposition / exfoliation. For example... Figure 3 As shown, the Zn / / Cu half-cell of Example 1 exhibits an average coulombic efficiency of up to 99.45% and can cycle stably for more than 1000 cycles. The Zn / / Cu half-cell of Comparative Example 1 can only cycle stably for 546 cycles, while the Zn / / Cu half-cell of Comparative Example 2 exhibits large fluctuations in coulombic efficiency within 200 cycles and has a lower average coulombic efficiency.

[0030] (4) Using the Zn / / Zn symmetric cells of Example 1 and Comparative Example 2 in Chorioamperometry (CA) measurements were performed at a potential of 150 mV to investigate the formation mechanism of uniform morphology in electrodeposited Zn, thereby effectively evaluating Zn. 2+ Surface diffusion behavior. For example... Figure 4 As shown, the response current of the symmetrical cell in Comparative Example 2 continuously increases, indicating that continuous 2D diffusion occurs on the electrode surface. Under this diffusion mode, Zn 2+ The particles tend to accumulate at protruding sites on the electrode surface, exacerbating the "point effect" and gradually forming dendrites. Conversely, Example 1 achieved a stable current density within a short time, forming a 3D diffusion mode in which Zn... 2+ The tendency to nucleate in situ after reaching the Zn anode surface helps to alleviate the "tip effect" and obtain a uniform Zn deposition morphology.

[0031] (5) Zn / / Zn symmetrical cells were assembled to evaluate the long-term cycle stability and reversibility of the zinc anode, in order to verify the positive effect of amlodipine benzyl sulfonate additive on stabilizing the zinc anode. For example... Figure 5 As shown, the symmetrical cell of Example 1 operates at 1.0 mA cm⁻¹ 2 and 1.0 mAh cm 2 Under the same operating conditions, the symmetrical cell of Example 2 achieved a cycle life of 4400 hours, the symmetrical cell of Example 3 achieved a cycle life of 2200 hours, and the symmetrical cell of Example 4 achieved a cycle life of 1900 hours. This was achieved when the areal capacity remained constant and the current density was increased.

[0032] As shown in Figure 6, the symmetrical cell of Example 1 at 3.0 mA cm⁻¹ 2 and 1.0 mAh cm 2 Under certain operating conditions, it achieved a cycle life of 2100 hours, which is approximately 61 times that of the symmetrical cell in Comparative Example 1 (34 hours). For example... Figure 7 As shown, the symmetrical cell of Example 1 operates at 4.0 mA cm⁻¹ 2 and 4.0 mAh cm 2 Under the specified operating conditions, it achieved a cycle life of 600 hours. Comparative Examples 1 and 2, however, both failed within 200 hours. Furthermore, as... Figure 8 As shown, for Zn / / Zn symmetric cells at 1.0, 2.0, 3.0, 4.0 and 5.0 mAcm 2 The test was conducted below, and the surface capacity is 1.0 mAh cm⁻¹. 2 The test results show that the electrolyte in Example 1 has a better current recovery ability.

[0033] (6) Electrochemical performance tests were conducted on coin cells assembled with the electrolyte materials of Example 1, Comparative Example 1, and Comparative Example 2 and ammonium vanadate cathodes, respectively. The results of the discharge specific capacity tests at different current densities are shown in Table 1 below: Table 1

[0034] As shown in Table 1 and Figure 9 As shown, the sample of Example 1 was tested at 1.0, 2.0, 3.0, 4.0, and 5.0 A·g. 1 At current densities of 491.3, 453.0, 422.0, 395.4, and 373.0 mAh g, respectively. 1 The discharge specific capacity when the current density returns to 1.0 A·g 1 The specific capacity recovered to 488.4 mAh g. 1 Comparative Example 1 samples were tested at concentrations of 1.0, 2.0, 3.0, 4.0, and 5.0 A·g. 1 At current densities of 420.7, 379.3, 348.5, 321.2 and 294.6 mAh g, respectively. 1 The specific capacity when the current density returns to 1.0 A·g 1 The specific capacity returned to 424.4 mAh g. 1 Comparative Example 2 samples were tested at concentrations of 1.0, 2.0, 3.0, 4.0, and 5.0 A·g. 1 At current densities of 374.5, 339.9, 309.8, 282.5 and 249.8 mAh g, respectively. 1 The specific capacity when the current density returns to 1.0 A·g 1 The specific capacity returned to 390.2 mAh g. 1 Therefore, it can be seen that the discharge specific capacity of Example 1 is significantly improved compared to the comparative example. Furthermore, from... Figure 10The cyclic voltammetry (CV) curves show that Example 1 and Comparative Example 2 exhibit similar electrochemical behavior, indicating that amlodipine besylate does not participate in the reaction in the full cell. The CV curve area of ​​Example 1 is larger, indicating that the introduction of amlodipine besylate results in a faster electrochemical reaction rate and more reaction sites at the full cell electrode.

[0035] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An aqueous zinc-ion battery electrolyte, characterized in that, It includes an electrolyte, an additive, and a solvent. The electrolyte is a soluble zinc salt, and the additive is amlodipine besylate. The concentration of the electrolyte is 0.5~3 mol / L, and the concentration of the additive is 0.02~0.16 mmol / L.

2. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The soluble zinc salt includes one or more of zinc sulfate, zinc chloride, zinc bromide, zinc nitrate, zinc acetate, and zinc trifluoromethanesulfonate.

3. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The solvent is an ethanol-water mixture, with a volume ratio of ethanol to water of 1:2 to 4.

4. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The aqueous zinc-ion battery electrolyte comprises zinc trifluoromethanesulfonate, amlodipine benzenesulfonate, and an ethanol-water mixture, wherein the molar concentration of zinc trifluoromethanesulfonate is 2 mol / L, the concentration of amlodipine benzenesulfonate is 0.04 mmol / L, and the volume ratio of ethanol to water is 1:

3.

5. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The preparation steps of the aqueous zinc-ion battery electrolyte include: first, dissolving the electrolyte in a solvent solution to obtain a mixed solution, and then adding additives to the mixed solution and stirring evenly to obtain the electrolyte.

6. The aqueous zinc-ion battery electrolyte according to claim 4, characterized in that, The stirring time is 12-24 hours.

7. An aqueous zinc-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and the aqueous zinc-ion battery electrolyte as described in claims 1 to 6.

8. The aqueous zinc-ion battery according to claim 7, characterized in that, The positive electrode material is one of vanadium-based materials, manganese-based materials, or Prussian blue compounds, and the negative electrode material is zinc sheet.

9. The aqueous zinc-ion battery according to claim 8, characterized in that, The cathode material includes vanadium-based materials, acetylene black, and a binder.

10. The aqueous zinc-ion battery according to claim 8, characterized in that, The vanadium-based material includes at least one of sodium vanadate, ammonium vanadate, or vanadium dioxide.

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