Deep eutectic electrolyte for stabilizing metal grid electrode and preparation method and application thereof
By designing a deep eutectic electrolyte, constructing an efficient ion conduction network, and forming a stable SEI film at the electrode interface, the stability problem of metal mesh electrodes in electrochemical reactions is solved, enabling long-term cycling of electrochromic devices.
Patent Information
- Application Number
- CN202510968898.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-28
AI Technical Summary
Existing technologies struggle to effectively stabilize metal mesh electrodes during long-term electrochemical reactions, resulting in poor device cycle stability.
By employing a deep eutectic electrolyte formed from metal salts and eutectic solvents, and through a solvation structure design with a specific composition, an efficient ion conduction network is constructed and a dense and stable SEI film is induced to form at the electrode interface, thereby synergistically regulating the interfacial deposition behavior of metal ions.
Significantly improve the stability of metal grid electrodes, achieve long-term cycling of electrochromic devices, optimize the electrochemical window and ionized solvent structure, and block electrolyte decomposition side reactions.
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Figure CN120848077A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a deep eutectic electrolyte, specifically to a deep eutectic electrolyte for stabilizing metal mesh electrodes, its preparation method, and its application, belonging to the field of materials science and technology. Background Technology
[0002] Transparent conductive electrodes (TCEs) are core components of modern optoelectronic devices, and their performance directly affects the device's response speed, optical contrast, and cycling stability. While traditional indium tin oxide (ITO) electrodes possess high transmittance and low sheet resistivity, they are brittle, not resistant to bending, and limited by the scarcity of indium resources, making them unsuitable for flexible electronics and low-cost mass production. Metal mesh electrodes, due to their unique high conductivity, excellent mechanical flexibility, and good optical transmittance, have become an ideal alternative to ITO. However, during long-term electrochemical reactions, metal meshes are prone to structural degradation and even melting, severely impacting the device's cycling stability.
[0003] Currently, existing technologies typically employ polymer additives (such as PVA and PEI) to promote the uniform and reversible deposition of active metals. The specific principle is that a physical barrier is formed at the electrode interface through surface adsorption. The directional alignment of the molecular chains homogenizes the electric field distribution and guides the orderly deposition of metal ions, thereby effectively suppressing dendrite growth and promoting uniform film formation. This exogenous modification mechanism mainly relies on the physicochemical interactions between additive molecules and the electrode surface. However, while single-interface modulation can optimize electrode surface deposition, it cannot control the electrochemical window, operating temperature range, or ionization-solvation structure of the electrolyte. Summary of the Invention
[0004] The main objective of this invention is to provide a deep eutectic electrolyte for stabilizing metal mesh electrodes and a method for preparing the same, in order to overcome the shortcomings of the prior art.
[0005] Another object of the present invention is to provide the application of the deep eutectic electrolyte.
[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:
[0007] This invention provides a deep eutectic electrolyte for stabilizing metal mesh electrodes, comprising: a complex formed by a metal salt and a eutectic solvent, wherein the eutectic solvent comprises one or more combinations of N-methylacetamide, ethylene glycol, acetamide, and N,N-dimethylacetamide.
[0008] In some embodiments, the molar ratio of the metal salt to the eutectic solvent is 1:2 to 1:12.
[0009] This invention also provides a method for preparing the deep eutectic electrolyte for stabilizing metal mesh electrodes, comprising: heating and stirring a mixture containing a metal salt and a eutectic solvent to obtain the deep eutectic electrolyte for stabilizing metal mesh electrodes.
[0010] This invention also provides the application of the deep eutectic electrolyte for stabilizing the metal mesh electrode in an electrochromic device with an active metal mesh as the counter electrode.
[0011] Furthermore, this embodiment of the invention also provides an electrochromic device with an active metal mesh as the counter electrode, comprising a transparent conductive electrode, an electrochromic material, an electrolyte, and a metal mesh electrode arranged sequentially, wherein the electrolyte is the aforementioned deep eutectic electrolyte used to stabilize the metal mesh electrode.
[0012] Compared with the prior art, the beneficial effects of the present invention include at least the following:
[0013] The deep eutectic electrolyte provided by this invention not only optimizes electrode interface deposition but also improves the electrolyte's electrochemical window, operating temperature range, and regulates the ionized solvent structure. Through its unique solvation structure design, it simultaneously achieves the dual functions of bulk transport optimization and interface stability. The solvation clusters with specific compositions not only construct an efficient ion conduction network but also induce the formation of a dense and stable SEI film at the electrode interface. This in-situ generated SEI film has excellent mechanical strength and ion selectivity, effectively blocking electrolyte decomposition side reactions. At the same time, it synergistically regulates the interfacial deposition behavior of metal ions, significantly improving the stability of the metal mesh electrode, thereby achieving long-term cycling of electrochromic devices. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0015] Figure 1 This is an optical photograph of deep eutectic electrolytes with different molar ratios of ZnCl2 to NMA at room temperature in a typical embodiment of the present invention;
[0016] Figure 2 This is a comparison of the SEM morphology of the zinc mesh electrode after 50, 100, 200, and 500 cycles in a deep eutectic electrolyte system with a ZnCl2 to NMA molar ratio of 1:4, a PC / Zn(ClO4)2 system, and a ZnSO4 system, according to a typical embodiment of the present invention. Detailed Implementation
[0017] In view of the shortcomings of the prior art, the inventors of this case, through long-term research and extensive practice, have been able to propose the technical solution of this invention, which mainly proposes to significantly improve the stability of metal mesh electrodes by designing a novel eutectic electrolyte (DEE), thereby achieving long-term cycling of the device.
[0018] The following will further explain the technical solution, its implementation process, and its principles. However, it should be understood that within the scope of this invention, the above-mentioned technical features of this invention and the technical features specifically described below (in embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here.
[0019] As one aspect of the technical solution of the present invention, a deep eutectic electrolyte for stabilizing metal grid electrodes includes: a complex formed by a metal salt and a eutectic solvent, wherein the eutectic solvent may include one or more of N-methylacetamide (NMA), ethylene glycol, acetamide, N,N-dimethylacetamide, etc., but is not limited thereto.
[0020] In some embodiments, the molar ratio of the metal salt to the eutectic solvent is 1:2 to 1:12, for example, it can be 1:2, 1:4, 1:6, 1:8, 1:10, 1:12, etc.
[0021] In some embodiments, the metal salt may include one or more of zinc chloride (ZnCl2), zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonyl)imide, silver chloride, silver bromide, silver nitrate, copper sulfate, copper chloride, copper nitrate, etc., but is not limited thereto.
[0022] Furthermore, the homogeneous deep eutectic electrolyte provided by the present invention can simultaneously optimize interface and bulk transport, thereby improving the interface stability and overall electrochemical performance of electrical devices.
[0023] As another aspect of the technical solution of the present invention, it also relates to a method for preparing the deep eutectic electrolyte for stabilizing metal grid electrodes, which includes: heating and stirring a mixture containing a metal salt and a eutectic solvent to obtain the deep eutectic electrolyte for stabilizing metal grid electrodes.
[0024] In some preferred embodiments, the preparation method specifically includes: mixing a metal salt and a eutectic solvent in a molar ratio of 1:2 to 1:12 to form the mixture.
[0025] In some preferred embodiments, the heating and stirring temperature is 50–100°C, and the time is 0.5–24 h.
[0026] As another aspect of the technical solution of the present invention, it also relates to the application of the deep eutectic electrolyte for stabilizing the metal mesh electrode in an electrochromic device with an active metal mesh as the counter electrode.
[0027] Accordingly, as another aspect of the technical solution of the present invention, it also relates to an electrochromic device with an active metal mesh as the counter electrode, comprising a transparent conductive electrode, an electrochromic material, an electrolyte and a metal mesh electrode arranged sequentially, wherein the electrolyte is the aforementioned deep eutectic electrolyte used to stabilize the metal mesh electrode.
[0028] In some preferred embodiments, the metal mesh electrode is any one of a zinc mesh electrode (obtained by depositing zinc on a stainless steel mesh), a silver mesh electrode, or a copper mesh electrode.
[0029] In some preferred embodiments, the transparent conductive electrode includes any one of ITO transparent conductive electrodes, silver nanowire transparent conductive electrodes, metal mesh transparent conductive electrodes, etc., but is not limited to this.
[0030] In some preferred embodiments, the electrochromic material may include one or more of polyaniline, tungsten oxide, Prussian blue, vanadium pentoxide, etc., but is not limited thereto.
[0031] By employing the above technical solutions, the deep eutectic electrolyte provided by this invention can not only optimize electrode interface deposition but also improve the electrolyte's electrochemical window, operating temperature range, and regulate the ionized solvent structure. The deep eutectic electrolyte can simultaneously achieve bulk transport optimization and interface stability through its unique solvation structure design. Specifically composed solvation clusters not only construct a highly efficient ion conduction network but also induce the formation of a dense and stable SEI film at the electrode interface. This in-situ generated SEI film exhibits excellent mechanical strength and ion selectivity, effectively blocking electrolyte decomposition side reactions while synergistically regulating the interfacial deposition behavior of metal ions.
[0032] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It should be noted that the following embodiments are intended to facilitate understanding of the present invention, and do not constitute any limitation thereof. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the manufacturer.
[0033] Example 1
[0034] This embodiment uses a deep eutectic electrolyte composed of ZnCl2 / NMA and a zinc-based electrochromic system as a model. The specific preparation process is as follows:
[0035] (1) Preparation of deep eutectic electrolyte (DEE)
[0036] Zinc chloride (ZnCl2) and N-methylacetamide (NMA) were mixed at a molar ratio of 1:4 and heated and stirred at 70°C for 2 hours to prepare a deep eutectic electrolyte (named DEE-1:4).
[0037] (2) Verification that deep eutectic electrolytes promote uniform zinc deposition and improve the stability of zinc grids
[0038] A zinc mesh / polyaniline electrochromic device based on the deep eutectic electrolyte prepared in step (1) was assembled. The zinc mesh was obtained by depositing zinc onto a stainless steel mesh, and the polyaniline electrode was prepared by depositing aniline on ITO glass using a three-electrode method. For comparison, the deep eutectic electrolyte prepared in step (1) was replaced with 1 M ZnSO4 and 1 M PC / Zn(ClO4)2, respectively, while other conditions remained unchanged, and the devices were assembled. The three electrochromic devices were subjected to electrochemical cycling (1.4 V / 20 s, 0.4 V / 20 s), and then the cycled devices were disassembled. The morphology of the zinc mesh was analyzed using SEM. Figure 2 The image shows a comparison of the SEM morphology of the zinc mesh electrode after 50, 100, 200, and 500 cycles in a DEE-1:4 deep eutectic electrolyte system, a PC / Zn(ClO4)2 system, and a ZnSO4 system. The experimental results show that in the aqueous ZnSO4 electrolyte, the zinc electrode surface exhibits obvious dendrite growth and corrosion. Even after 50 cycles, significant uneven deposition appears on the electrode surface, and the surface roughness worsens with increasing cycle number, accompanied by significant electrode volume expansion. In contrast, in the DEE-1:4 and PC / Zn(ClO4)2 organic electrolyte systems, the zinc deposition exhibits better morphological uniformity, with smaller and more uniformly distributed grain sizes. Quantitative analysis showed that after 500 cycles, the zinc electrode diameter of the DEE-1∶4 system increased by only 1 μm, which was significantly lower than the 6.5 μm expansion of the PC / Zn(ClO4)2 system. This indicates that the deep eutectic electrolyte (DEE) prepared in step (1) of this embodiment can more effectively promote the uniform deposition of zinc and improve the stability of the zinc grid.
[0039] In the deep eutectic electrolyte prepared in this embodiment, Zn 2+ It has a strong coordination relationship with the carbonyl group (C=O) of NMA, forming [ZnCl(NMA)] + [ZnCl(NMA)2] + [ZnCl(NMA)3] +The reason why these complexes can improve interfacial stability and overall electrochemical performance is that they form a stable organic-inorganic SEI film during the dissociation-reduction process on the zinc electrode. The SEI film not only acts as a protective layer to suppress side reactions and achieve a uniform electric field distribution, but also optimizes the diffusion behavior of zinc ions at the interface, thereby achieving stable zinc ion transfer. Furthermore, it enables the nucleation and deposition of zinc ions on the 002 crystal plane, which has a high activation energy and can induce uniform growth of zinc metal, forming a dendrite-free structure.
[0040] Example 2
[0041] Zinc chloride (ZnCl2) and N-methylacetamide (NMA) were mixed at a molar ratio of 1:12 and heated and stirred at 70°C for 2 hours to prepare a deep eutectic electrolyte.
[0042] Example 3
[0043] Zinc chloride (ZnCl2) and ethylene glycol were mixed at a molar ratio of 1:4 and heated and stirred at 70°C for 2 hours to prepare a deep eutectic electrolyte.
[0044] Example 4
[0045] Zinc bis(trifluoromethylsulfonyl)imide and N-methylacetamide were mixed at a molar ratio of 1:4 and heated and stirred at 70°C for 2 hours to prepare a deep eutectic electrolyte.
[0046] Example 5
[0047] Zinc chloride (ZnCl2) and ethylene glycol were mixed at a molar ratio of 1:2 and heated and stirred at 100°C for 0.5 hours to prepare a deep eutectic electrolyte.
[0048] Example 6
[0049] Zinc chloride (ZnCl2) and N-methylacetamide were mixed at a molar ratio of 1:6 and heated and stirred at 50°C for 2 hours to prepare a deep eutectic electrolyte.
[0050] Example 7
[0051] Zinc chloride (ZnCl2) and N-methylacetamide were mixed at a molar ratio of 1:8 and heated and stirred at 50°C for 24 hours to prepare a deep eutectic electrolyte.
[0052] Example 8
[0053] Zinc trifluoromethanesulfonate and acetamide were mixed at a molar ratio of 1:10 and heated and stirred at 80°C for 10 hours to prepare a deep eutectic electrolyte.
[0054] Figure 1Optical photographs of deep eutectic electrolytes with different molar ratios of ZnCl2 to NMA at room temperature in the above embodiments.
[0055] Example 9
[0056] Silver chloride and N,N-dimethylacetamide were mixed at a molar ratio of 1:10 and heated and stirred at 80°C for 10 hours to prepare a deep eutectic electrolyte.
[0057] Example 10
[0058] Copper chloride and N-methylacetamide were mixed at a molar ratio of 1:10 and heated and stirred at 80°C for 10 hours to prepare a deep eutectic electrolyte.
[0059] Tests showed that the deep eutectic electrolytes obtained in Examples 9 and 10 could also more effectively promote the uniform deposition of silver or copper and improve the stability of the metal mesh electrode.
[0060] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.
[0061] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A deep eutectic electrolyte for stabilizing metal mesh electrodes, characterized in that, include: A complex formed from a metal salt and a eutectic solvent, wherein the eutectic solvent comprises one or more combinations of N-methylacetamide, ethylene glycol, acetamide, and N,N-dimethylacetamide.
2. The deep eutectic electrolyte for stabilizing metal mesh electrodes according to claim 1, characterized in that: The molar ratio of the metal salt to the eutectic solvent is 1:2 to 1:
12.
3. The deep eutectic electrolyte for stabilizing metal mesh electrodes according to claim 1, characterized in that: The metal salt is an active metal salt, including one or more combinations of zinc chloride, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonyl)imide, silver chloride, silver bromide, silver nitrate, copper sulfate, copper chloride, and copper nitrate.
4. The method for preparing a deep eutectic electrolyte for stabilizing a metal mesh electrode as described in any one of claims 1-3, characterized in that, include: The deep eutectic electrolyte for stabilizing the metal grid electrode is prepared by heating and stirring a mixture containing a metal salt and a eutectic solvent.
5. The preparation method according to claim 4, characterized in that, include: The metal salt and eutectic solvent are mixed in a molar ratio of 1:2 to 1:12 to form the mixture.
6. The preparation method according to claim 4, characterized in that: The heating and stirring temperature is 50–100°C, and the time is 0.5–24 h.
7. The application of the deep eutectic electrolyte for stabilizing the metal mesh electrode as described in any one of claims 1-3 in an electrochromic device with an active metal mesh as the counter electrode.
8. An electrochromic device using an active metal mesh as the counter electrode, comprising a transparent conductive electrode, an electrochromic material, an electrolyte, and a metal mesh electrode arranged sequentially, characterized in that: The electrolyte is the deep eutectic electrolyte for stabilizing the metal mesh electrode as described in any one of claims 1-3.
9. The electrochromic device according to claim 8, characterized in that: The metal mesh electrode includes any one of zinc mesh electrode, silver mesh electrode, and copper mesh electrode; And / or, the transparent conductive electrode includes any one of ITO transparent conductive electrode, silver nanowire transparent conductive electrode, and metal mesh transparent conductive electrode.
10. The electrochromic device according to claim 8, characterized in that: The electrochromic material includes one or more of polyaniline, tungsten oxide, Prussian blue, and vanadium pentoxide.