Water-based zinc ion battery electrolyte containing a chain polyether additive and application thereof

Abstract

The application discloses a water-based zinc ion battery electrolyte containing a chain polyether additive and application thereof, and belongs to the technical field of water-based zinc ion batteries. By adding 0.05-0.5 mol / L of an ether additive in the electrolyte of a water-based zinc ion battery, triple synergistic effects are realized: the solvation structure of zinc ions is adjusted, free water is reduced, and hydrogen evolution and side reactions are inhibited; zinc is induced to preferentially grow along a (002) crystal surface, dendrites are inhibited, and corrosion resistance is improved; and the ether additive participates in the formation of a dense and stable SEI film to block water molecules from contacting the zinc negative electrode. The electrolyte is suitable for Zn||Zn symmetric batteries, Zn||Cu asymmetric batteries and full battery systems such as Zn||vanadium-based positive electrodes, can significantly improve the cycle life and coulombic efficiency of the batteries, and has important practical value.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery technology, specifically relating to an aqueous zinc-ion battery electrolyte containing chain-like polyether additives and its application. Background Technology

[0002] Aqueous zinc-ion batteries have shown great application potential in the field of large-scale energy storage due to their inherent safety, low cost, environmental friendliness, and the high theoretical capacity (820 mAh / g) and low redox potential (-0.76 V vs. SHE) of zinc metal anode.

[0003] However, the commercialization of aqueous zinc-ion batteries still faces severe challenges, with the main bottleneck being the irreversible side reactions at the zinc anode / electrolyte interface. In traditional aqueous electrolytes, direct contact between free water molecules and the zinc anode surface leads to hydrogen evolution side reactions and induces local alkalization, generating inert basic zinc sulfate and other byproducts. Simultaneously, the dendrites formed by uneven zinc deposition can puncture the separator, causing a short circuit. Furthermore, randomly oriented zinc deposition exposes highly active (100), (101), and other crystal planes, further exacerbating side reactions and corrosion. These problems collectively result in low coulombic efficiency and shortened cycle life of the zinc anode, severely restricting the performance and practical application of aqueous zinc-ion batteries.

[0004] To stabilize the zinc anode interface, existing technologies mainly focus on: 1) constructing artificial protective layers; 2) developing high-concentration electrolytes; and 3) introducing electrolyte additives. Among these, the electrolyte additive strategy has attracted much attention due to its simplicity and efficiency. However, most additive research focuses on suppressing side reactions, while research on the precise control of the crystallographic orientation of zinc deposition and the synergistic optimization of interfacial chemistry and solvation structure is still insufficient. In particular, there are very few reports on single additive systems that can simultaneously control the zinc ion solvation structure, induce the preferred growth of zinc (002) crystal faces, and participate in the formation of a stable solid-state electrolyte interfacial film.

[0005] Therefore, developing a novel electrolyte additive that can synergistically solve the aforementioned multiple interface problems is of great significance for promoting the development of high-performance aqueous zinc-ion batteries. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide an aqueous zinc-ion battery electrolyte containing chain-like polyether additives.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The aqueous zinc-ion battery electrolyte contains a chain polyether of general formula (I); HO-(CH2CH2O) x -(CH2) y -H formula (I); In the formula, x is an integer from 4 to 20, and y is an integer from 1 to 15.

[0010] As a preferred embodiment of the aqueous zinc-ion battery electrolyte containing chain polyether additives according to the present invention, the chain polyether includes one or more of monododecyl nonethylene glycol ether, tetraethylene glycol monododecyl ether, nonethylene glycol monomethyl ether, and eicosyl glycol dodecyl ether.

[0011] As a preferred embodiment of the aqueous zinc-ion battery electrolyte containing chain polyether additives according to the present invention, the molar concentration of the chain polyether in the aqueous zinc-ion battery electrolyte is 0.05 mol / L to 0.6 mol / L.

[0012] As a preferred embodiment of the aqueous zinc-ion battery electrolyte containing chain-like polyether additives according to the present invention, the aqueous zinc-ion battery electrolyte further includes zinc salt with a molar concentration of 0.5 mol / L to 3 mol / L.

[0013] As a preferred embodiment of the aqueous zinc-ion battery electrolyte containing chain-like polyether additives according to the present invention, the zinc salt includes one or more of bis(trifluoromethanesulfonyl)imide zinc, zinc trifluoromethanesulfonate, zinc perchlorate, zinc nitrate, and zinc acetate.

[0014] Another object of the present invention is to provide an application of an aqueous zinc-ion battery electrolyte containing chain-like polyether additives in the preparation of aqueous zinc-ion batteries.

[0015] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An aqueous zinc-ion battery includes the aqueous zinc-ion battery electrolyte containing chain-like polyether additives, and further includes a positive electrode, a negative electrode, and a separator.

[0016] The aqueous zinc-ion battery includes one of the following: a Zn||Zn symmetric cell, a Zn||Cu asymmetric cell, or a Zn|| positive electrode full cell with manganese-based oxide, vanadium-based oxide, or Prussian blue-like compound as the positive electrode.

[0017] Beneficial effects of this invention: (1) By introducing ether additives, the present invention adjusts the solvation structure of zinc ions in the electrolyte, significantly reducing the free water content and water activity in the solvation structure, thereby effectively inhibiting the hydrogen evolution reaction and the generation of by-products from the source; (2) The additive molecules can be specifically adsorbed on the surface of the zinc anode. Under the regulation of ether additives, the zinc anode after cycling exhibits a highly preferred (002) crystal orientation. This highly preferred (002) crystal orientation not only effectively inhibits the formation of zinc dendrites, but its excellent chemical stability also significantly slows down the corrosion rate of the zinc anode.

[0018] (3) During charge-discharge cycles, some additive molecules or their reduction decomposition products participate in the formation of a dense and stable solid electrolyte interface film. This organic-inorganic composite SEI film has good Zn content. 2+ Its conductivity acts as a highly efficient physical and chemical barrier, effectively preventing direct contact between free water molecules and the active material of the zinc negative electrode, inhibiting water decomposition side reactions, and further greatly improving the chemical and electrochemical stability of the electrode-electrolyte interface.

[0019] (4) By introducing ether additives with specific structures, a high-performance aqueous zinc-ion battery electrolyte was successfully constructed. Through multiple synergistic effects, the cycle stability and coulombic efficiency of the battery were significantly improved, which has important practical value. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the 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. Wherein: Figure 1 This is a comparison of the Raman spectra of the electrolytes from Example 1 and Comparative Example 1 in this invention; Figure 2 The images show the SEM morphology of the zinc negative electrode after cycling in the electrolytes of Example 1 and Comparative Example 1 in this invention. Figure 3 This is a comparison of XRD patterns of zinc anodes after cycling in the electrolytes of Example 1 and Comparative Example 1 in this invention; Figure 4 The Zn||Zn symmetric cell containing the electrolytes of Example 1 and Comparative Example 1 in this invention is used at 1 mA cm⁻¹ -2 Comparison of long-cycle performance under certain conditions; Figure 5The Zn||Cu asymmetric cell containing the electrolytes of Example 1 and Comparative Example 1 in this invention was tested at 1 mA cm⁻¹. -2 A comparison chart of Coulomb efficiency; Figure 6 The full cell containing the electrolytes of Example 1 and Comparative Example 1 in this invention was tested at 5 A g. -1 A comparison chart of long-cycle performance. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0025] The method for testing the electrochemical performance of materials in this invention is as follows: Using zinc foil as the negative electrode, an electrode sheet coated with positive electrode active material or zinc foil or copper foil as the positive electrode, and a glass fiber membrane as the separator; 60-120 μL of the electrolyte prepared in each example or comparative example is dropped onto the separator and encapsulated to obtain a battery; the encapsulated battery is left to stand at 20-30°C for 2-6 hours and then subjected to electrochemical testing.

[0026] Example 1 This embodiment provides an aqueous zinc-ion battery electrolyte containing chain-like polyether additives: Composed of monododecyl nonaethylene glycol ether (x=9, y=12, i.e., HO-(CH2CH2O)9-(CH2) 12 The solution was prepared by mixing monododecyl nonaethylene glycol ether (-H), zinc trifluoromethanesulfonate, and deionized water, wherein the molar concentration of monododecyl nonaethylene glycol ether was 0.1 mol / L and the concentration of zinc trifluoromethanesulfonate was 1 mol / L.

[0027] Comparative Example 1 Compared with Example 1, this comparative example omits monododecyl nonethylene glycol ether and prepares an electrolyte with a zinc trifluoromethanesulfonate concentration of 1 mol / L.

[0028] Figure 1 This is a comparison of the Raman spectra of the electrolytes from Example 1 and Comparative Example 1 in this invention. Figure 1 It can be clearly observed that the introduction of chain-like polyether additives disrupts the original hydrogen bond network between solvent molecules. The hydrophilic hydroxyl ends of these ether additives form highly ordered aggregate structures with water, while the hydrophobic segments repel water molecules, leading to an increase in the proportion of highly disordered free water, thereby reconstructing the solvation environment.

[0029] The electrolytes from Example 1 and Comparative Example 1 were used to prepare aqueous zinc-ion batteries. The zinc anodes after cycling in these electrolytes were characterized by SEM morphology and XRD analysis. The results are as follows: Figure 2 , 3 As shown.

[0030] Figure 2 , 3 It can be clearly observed that after the addition of chain-like polyether additives, the deposition morphology on the zinc anode surface is more uniform and dense, and the relative intensity of the (002) crystal plane diffraction peak of Zn in the XRD pattern is significantly enhanced. This indicates that the introduction of chain-like polyether additives can not only regulate the solvation environment, but also induce zinc to preferentially deposit along the (002) crystal plane direction. This orientation is generally beneficial for achieving more uniform zinc deposition and suppressing dendrite growth.

[0031] The electrolytes obtained in Example 1 and Comparative Example 1 were used to prepare aqueous zinc-ion batteries. The electrochemical performance of these batteries was tested, and the results are as follows: Figure 4 , 5 As shown in Table 1, 6, and 1.

[0032] Table 1. Effect of presence or absence of chain polyether additives on battery performance According to Table 1 and Figure 3 , 4 As can be seen from point 5, the addition of chain-like polyether additives to aqueous zinc-ion batteries not only improves the cycle stability and deposition / dissolution reversibility of the zinc anode, but also solves the problem of a sharp reduction in lifespan caused by side reactions.

[0033] Example 2 Compared with Example 1, the concentration of monododecyl nonaethylene glycol ether in this embodiment was adjusted to 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.2 mol / L, 0.6 mol / L, and 0.8 mol / L, respectively. The other components were the same as in Example 1, resulting in electrolytes with different concentrations of monododecyl nonaethylene glycol ether in this embodiment.

[0034] Electrolytes with different additive concentrations in this embodiment were assembled into aqueous zinc-ion batteries. The electrochemical performance of the batteries was tested and compared with that of Example 1 and Comparative Example 1. The results are shown in Table 2.

[0035] Table 2. Effect of different concentrations of chain polyether additives on battery performance Table 2 shows that adding ether additives can improve the cycle life of the zinc anode. However, it is also observed that the cycle life of the corresponding battery does not increase indefinitely with increasing ether additive concentration. This may be related to the excessive adsorption of zinc anode by excessive ether additives, hindering zinc ion transport. Among the symmetrical batteries, the one with the highest ether additive concentration (0.1 mol / L) exhibits the longest cycle life under high current, reaching 400 hours, demonstrating the best overall performance.

[0036] Example 3 Compared with Example 1, this embodiment adjusts the monododecyl nonethylene glycol ether to tetraethylene glycol monododecyl ether (x=4, y=12, i.e., HO-(CH2CH2O)4-(CH2). 12 -H), and the remaining components are as described in Example 1 to obtain the electrolyte of this example.

[0037] Example 4 Compared with Example 1, this embodiment adjusts the monododecyl nonethylene glycol ether to nonethylene glycol monomethyl ether (x=9, y=1, i.e., HO-(CH2CH2O)9-CH3), and the other components are the same as in Example 1, to obtain the electrolyte of this embodiment.

[0038] Example 5 Compared with Example 1, this embodiment adjusts the monododecyl nonethylene glycol ether to eicosyl glycol dodecyl ether (x=20, y=12, i.e., HO-(CH2CH2O)). 20 -(CH2) 12 -H), and the remaining components are as described in Example 1 to obtain the electrolyte of this example.

[0039] Comparative Example 2 Compared with Example 1, this comparative example adjusts the monododecyl nonethylene glycol ether to eicosyl glycol (x=20, y=20, i.e., HO-(CH2CH2O)). 20 -(CH2) 20 -H), and the remaining components were as described in Example 1 to obtain the electrolyte of this comparative example.

[0040] Comparative Example 3 Compared with Example 1, this comparative example adjusts the monododecyl nonethylene glycol ether to dodecyl glycol eicosyl ether (x=12, y=20, i.e., HO-(CH2CH2O)). 12 -(CH2) 20 -H), and the remaining components were as described in Example 1 to obtain the electrolyte of this comparative example.

[0041] Comparative Example 4 Compared with Example 1, the electrolyte of this comparative example was obtained by adjusting the monododecyl nonethylene glycol ether to HPEG-2400 (methyl allyl polyoxyethylene ether with a number average molecular weight of 2400 Da), the concentration of zinc trifluoromethanesulfonate to 2 mol / L, and the other components to be the same as in Example 1.

[0042] The electrolytes from Examples 3 to 5 and Comparative Examples 2 to 4 were assembled into aqueous zinc-ion batteries. The electrochemical performance of the batteries was tested and compared with that of Example 1 and Comparative Example 1. The results are shown in Table 3.

[0043] Table 3. Effects of different types of chain polyether additives on battery performance As shown in Table 3, the type of ether additive has a significant impact on the performance of the zinc anode in aqueous zinc-ion batteries. This phenomenon is attributed to the balance among the functional groups in different ether additive molecules. This balance collectively optimizes the interfacial adsorption and solvation structure of zinc ions and guides a more stable interfacial deposition process. Based on the table, the best technical effect can be obtained when the ether additive in this invention is monododecyl nonaethylene glycol ether.

[0044] In summary, existing aqueous zinc-ion batteries suffer from problems such as unstable zinc anode interface, easy hydrogen evolution, dendrite formation, and severe side reactions, leading to poor cycle life and coulombic efficiency. This invention addresses these issues by introducing specific ether additives to alter the solvation structure of zinc ions, induce preferential growth of the zinc (002) crystal plane, and participate in the formation of a stable SEI film, thereby improving the battery's interface stability, cycle life, and coulombic efficiency.

[0045] In addition, by optimizing the electrolyte composition, not only is the cycle reversibility of the zinc anode improved, but the problem of lifespan degradation caused by side reactions is also solved. Furthermore, due to the simple electrolyte formulation and good compatibility with existing battery manufacturing processes, it provides the possibility for the rapid commercialization of long-life zinc-ion batteries.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An aqueous zinc-ion battery electrolyte containing chain-like polyether additives, characterized in that: The aqueous zinc-ion battery electrolyte contains a chain polyether of general formula (I); HO-(CH2CH2O) x -(CH2) y -H formula (I); In the formula, x is an integer from 4 to 20, and y is an integer from 1 to 15.

2. The aqueous zinc-ion battery electrolyte containing chain-like polyether additives as described in claim 1, characterized in that: The chain polyether includes one or more of monododecyl nonethylene glycol ether, tetraethylene glycol monododecyl ether, nonethylene glycol monomethyl ether, and eicosyl glycol dodecyl ether.

3. The aqueous zinc-ion battery electrolyte containing chain-like polyether additives as described in claim 1, characterized in that: The molar concentration of the chain polyether in the aqueous zinc-ion battery electrolyte is 0.05 mol / L to 0.6 mol / L.

4. The aqueous zinc-ion battery electrolyte containing chain-like polyether additives as described in claim 3, characterized in that: The aqueous zinc-ion battery electrolyte also includes zinc salts with a molar concentration of 0.5 mol / L to 3 mol / L.

5. The aqueous zinc-ion battery electrolyte containing chain-like polyether additives as described in claim 4, characterized in that: The zinc salt includes one or more of bis(trifluoromethanesulfonyl)imide zinc, zinc trifluoromethanesulfonate, zinc perchlorate, zinc nitrate, and zinc acetate.

6. The application of the aqueous zinc-ion battery electrolyte as described in any one of claims 1 to 5 in the preparation of aqueous zinc-ion batteries.

7. An aqueous zinc-ion battery, characterized in that: The electrolyte for an aqueous zinc-ion battery as described in any one of claims 1 to 5 further includes a positive electrode, a negative electrode, and a separator.

8. The aqueous zinc-ion battery as described in claim 7, characterized in that: The aqueous zinc-ion battery includes one of the following: a Zn||Zn symmetric cell, a Zn||Cu asymmetric cell, or a Zn|| positive electrode full cell with manganese-based oxide, vanadium-based oxide, or Prussian blue-like compound as the positive electrode.

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