Double-layer interface improves zinc negative electrode of aqueous zinc-ion battery and preparation method and application thereof
By constructing a double-layer interface of polydimethylsiloxane and organic electrolyte on the surface of the zinc anode, the zinc anode is isolated from the aqueous electrolyte, thus solving the problems of zinc anode corrosion and hydrogen evolution reaction, and improving the electrochemical performance and cycle life of aqueous zinc-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUBEI UNIV
- Filing Date
- 2026-03-13
- Publication Date
- 2026-07-21
Smart Images
Figure CN122436424A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aqueous zinc-ion battery technology, specifically to a zinc anode for aqueous zinc-ion batteries with improved double-layer interface, its preparation method, and its application. Background Technology
[0002] In recent years, industrial production and infrastructure construction have developed rapidly, and renewable energy sources such as solar, wind, and tidal energy have gained attention. Lithium-ion batteries have developed rapidly and have been widely used in electronic devices, electric vehicles, and other fields. However, their development is limited by factors such as limited lithium resource reserves and the flammability of electrolytes. Aqueous zinc-ion batteries, due to their inherent safety, natural abundance, and higher theoretical capacity, have gradually developed into highly competitive and efficient energy storage devices. Compared with rechargeable batteries based on organic electrolytes, aqueous rechargeable batteries have broad application prospects in electrochemical energy storage.
[0003] Because zinc anodes are in direct contact with aqueous electrolytes, they are prone to hydrogen evolution reactions, accompanied by irreversible zinc corrosion and loss of active materials. Simultaneously, byproducts from these side reactions may deposit on the zinc surface, hindering ion transport, accelerating capacity decay, and severely impairing the battery's cycle life and safety. Aqueous zinc-ion batteries lack the stable solid-state electrolyte interface film found in organic lithium-ion batteries. The anode / electrolyte interface is thermodynamically always in an "active" state; even when not in operation, corrosion and side reactions continue "silently," continuously consuming active materials, degrading the interface, and generating gas. This characteristic poses a severe challenge to the practical application of these batteries.
[0004] To address these issues, researchers have explored various methods, such as electrolyte engineering, interface control, and cycling strategy optimization, to suppress dendrite formation, reduce side reactions, and improve cycle reversibility. However, these methods still have limitations and have not fundamentally solved the zinc anode corrosion problem. Summary of the Invention
[0005] The purpose of this invention is to overcome the aforementioned problems in the prior art and to provide a double-layer interface improved zinc anode for aqueous zinc-ion batteries, its preparation method, and its application. The method of this invention, through the synergistic effect of PDMS coating and trace organic electrolyte, cuts off the direct contact between the zinc anode and the aqueous electrolyte without hindering the transport of zinc ions, thereby improving the hydrogen evolution reaction of the zinc anode and the formation of by-reaction products, and improving the calendar aging problem and long cycle life of zinc-ion batteries.
[0006] To achieve the above objectives, the present invention provides a zinc anode for an aqueous zinc-ion battery with improved dual-layer interface. The zinc anode for an aqueous zinc-ion battery with improved dual-layer interface includes a zinc sheet, on which a polydimethylsiloxane layer and an organic electrolyte layer are sequentially coated.
[0007] Preferably, the thickness of the polydimethylsiloxane layer is 30~50 nm.
[0008] Preferably, the raw material for the organic electrolyte layer is an organic electrolyte containing inorganic zinc salt and organic solvent; The concentration of inorganic zinc salt in the organic electrolyte is 0.5~1 mol / L.
[0009] Preferably, the inorganic zinc salt is zinc trifluoromethanesulfonate and / or zinc tetrafluoroborate; The organic solvent is N-methylformamide and / or trimethyl phosphate.
[0010] Preferably, the ratio of the amount of organic electrolyte to the area of the zinc sheet is 3~7 μL: 1 cm². 2 .
[0011] A second aspect of the present invention provides a method for preparing the above-mentioned double-layer interface improved zinc anode of an aqueous zinc-ion battery, comprising: Polydimethylsiloxane was coated onto the surface of a zinc sheet, which was then subjected to a series of steps including standing, UV irradiation, cleaning, and drying. Subsequently, an organic electrolyte was coated onto the surface to obtain a zinc anode for an aqueous zinc-ion battery with a double-layer interface improvement.
[0012] Preferably, the settling time is 1 to 5 minutes.
[0013] Preferably, the conditions for ultraviolet irradiation include: a power of 20-30 W, a wavelength of 250-340 nm, a distance of 7-10 cm, and a time of 30-40 min.
[0014] The third aspect of this invention provides the application of the above-mentioned double-layer interface improved zinc anode in aqueous zinc-ion batteries in the preparation of aqueous zinc-ion batteries.
[0015] A fourth aspect of the present invention provides an aqueous zinc-ion battery, the aqueous zinc-ion battery comprising the above-mentioned double-layer interface-improved aqueous zinc-ion battery zinc anode and an aqueous electrolyte; The aqueous electrolyte is a zinc sulfate solution and / or a zinc chloride solution.
[0016] The advantages of this invention are: 1. The preparation process of this invention is simple, highly repeatable, produces a uniform coating, and can be prepared on a large scale.
[0017] 2. Polydimethylsiloxane (PDMS) is grafted onto the zinc sheet surface to form a dense coating that blocks the aqueous electrolyte, effectively inhibiting zinc anode corrosion and zinc dendrite growth.
[0018] 3. Organic electrolytes are more likely to form a stable interface on PDMS@Zn substrates, which is beneficial for the added organic electrolytes to form a uniform SEI film on the surface.
[0019] 4. When in direct contact with aqueous electrolytes, PDMS coatings may fail due to long-term immersion, penetration, or accumulation of interfacial byproducts. Organic electrolytes, on the other hand, greatly reduce the chemical erosion and physical damage to the PDMS coating itself, thus extending the service life of the coating.
[0020] 5. The PDMS coating grafted onto the zinc sheet has a nanoscale or nanoscale pore and structural network inside, which can draw in and temporarily retain low-viscosity organic electrolyte through capillary forces.
[0021] This invention grafts polydimethylsiloxane (PDMS) onto the surface of a zinc sheet to form a coating. This coating, together with a trace amount of organic electrolyte, forms a double barrier that prevents the aqueous electrolyte from directly contacting the zinc anode. This effectively inhibits the formation of zinc dendrites and anode corrosion, thereby improving the electrochemical performance and stability of the battery. Attached Figure Description
[0022] Figure 1 This is a flowchart of a method for preparing a zinc anode in an aqueous zinc-ion battery with improved double-layer interface. Figure 2 This refers to the stratification phenomenon between the organic electrolyte and the ZnSO4 solution in Examples 1 and 2; Figure 3 The images show the scanning electron microscope (SEM) image and EDS (energy dispersive spectroscopy) elemental distribution of PDMS@Zn in Example 1. Figure 4 XPS plot of PDMS@Zn in Example 1; Figure 5 Optical comparison photographs of the symmetrical batteries assembled in Example 1 and Comparative Example 1 after being left to stand for 5, 10, 15, and 20 days, respectively. Figure 6 Optical comparison photographs of the symmetrical batteries assembled in Example 3 and Comparative Example 2 after being left to stand for 5, 10, 15, and 20 days, respectively. Figure 7 SEM images comparing the symmetrical cells assembled in Example 1 and Comparative Example 1 after being left to rest for 5, 10, 15, and 20 days, respectively. Figure 8 SEM comparison images of the symmetrical cells assembled in Example 3 and Comparative Example 2 after being left to stand for 5, 10, 15 and 20 days, respectively. Figure 9 The XRD patterns of the symmetrical cells assembled in Example 1 and Comparative Example 1 after being left to stand for 5, 10, 15 and 20 days, respectively. Figure 10 The XRD patterns of the symmetrical cells assembled in Example 3 and Comparative Example 2 after being left to stand for 5, 10, 15 and 20 days, respectively. Figure 11 The long cycle life of the symmetrical batteries assembled in Example 1 and Comparative Example 1 after being left to stand for 5, 10, 15 and 20 days, respectively; Figure 12 The long cycle life of the symmetrical batteries assembled in Example 3 and Comparative Example 2 after being left to stand for 5, 10, 15 and 20 days, respectively; Figure 13 The full cells assembled for Example 4 and Comparative Example 3 exhibit long cycle life at 2 C current. Detailed Implementation
[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0024] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0025] Furthermore, the technical solutions provided in the various embodiments of the present invention can be combined with each other, but only if they are feasible to those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0026] The present invention provides a zinc anode for an aqueous zinc-ion battery with improved dual-layer interface. The zinc anode for the aqueous zinc-ion battery with improved dual-layer interface includes a zinc sheet, on which a polydimethylsiloxane layer and an organic electrolyte layer are sequentially coated.
[0027] Since side reactions at the zinc anode often occur at the electrode / electrolyte interface, improving zinc anode corrosion by constructing a zinc anode interface layer to directly isolate the zinc anode from the electrolyte has become a research hotspot. In zinc-ion batteries, bilayer interface design is a cutting-edge and highly promising strategy. Its core idea is to construct an interface layer with dual functional characteristics or a gradient structure on the zinc anode surface to achieve precise control over ion transport, deposition behavior, and the interface environment. Its greatest advantage lies in its "synergistic integration" concept. It cleverly and synergistically optimizes the contradictory needs of corrosion prevention and ion conduction, as well as blocking and guiding, which were previously difficult to address with a single interface layer, fundamentally solving the interface problems of the zinc anode. Therefore, this invention designs a bilayer interface to improve zinc anode corrosion and zinc dendrite problems in aqueous zinc-ion batteries, which is of great significance for improving the calendar aging problem of aqueous zinc-ion batteries.
[0028] The thickness of the polydimethylsiloxane layer is in the nanometer range, specifically 30~50 nm.
[0029] In this invention, the raw material for the organic electrolyte layer is an organic electrolyte, obtained by directly coating the surface of the polydimethylsiloxane layer with the organic electrolyte. The organic electrolyte contains inorganic zinc salts and organic solvents, obtained by mixing the inorganic zinc salts and organic solvents. The organic electrolyte must separate from the aqueous electrolyte; otherwise, it is easily lost and cannot form a dense protection for the polydimethylsiloxane layer. Therefore, the inorganic zinc salts are preferably zinc trifluoromethanesulfonate (Zn(OTf)2) and / or zinc tetrafluoroborate (Zn(BF4)2). The purpose of selecting these two inorganic zinc salts is to provide migratable zinc ions, ensuring efficient transport of zinc ions within the protective layer and allowing for normal deposition and dissolution. The purpose of adding the organic electrolyte is to form an anti-corrosion layer; however, without inorganic zinc salts, there will be no mobile zinc ions at the interface, increasing interfacial impedance and potentially affecting battery performance.
[0030] Preferably, the organic solvent is N-methylformamide (NMF) and / or trimethyl phosphate (TMP).
[0031] In this invention, the concentration of inorganic zinc salt in the organic electrolyte is 0.5~1 mol / L. If the concentration is too high, dissolution will be difficult and the solution will be uneven; if the concentration is too low, it will affect the battery interface impedance, leading to an increase in battery polarization voltage. This is the most suitable concentration range.
[0032] In some specific embodiments, when the inorganic zinc salt is zinc trifluoromethanesulfonate, the organic solvent used is a mixture of N-methylformamide and trimethyl phosphate, and the volume ratio of N-methylformamide to trimethyl phosphate is 1:1; when the inorganic zinc salt is zinc tetrafluoroborate, the organic solvent used is trimethyl phosphate.
[0033] Furthermore, the ratio of the amount of organic electrolyte to the area of the zinc sheet is 3~7 μL: 1 cm². 2 .
[0034] In this invention, the polydimethylsiloxane layer and the organic electrolyte work in coordination. The thickness of the polydimethylsiloxane layer is on the nanometer scale. If too much organic electrolyte is added, the polydimethylsiloxane layer will swell, and the excess organic electrolyte will become a free layer, remaining on the electrode surface and affecting zinc ion transport. If the amount is too low, a uniform and continuous protective layer cannot be formed, and the polydimethylsiloxane layer will be directly exposed. Therefore, it is more appropriate to control the amount of organic electrolyte within the above range.
[0035] The ratio of the amount of organic electrolyte to the area of the zinc sheet refers to the ratio of the amount of organic electrolyte on one side to the area of the zinc sheet, that is, the ratio of the amount of organic electrolyte on one side to the area of the corresponding side of the zinc sheet.
[0036] The second aspect of the present invention provides a method such as Figure 1 The above-described method for preparing a zinc anode in an aqueous zinc-ion battery with improved bilayer interface includes: Polydimethylsiloxane was coated onto the surface of a zinc sheet, which was then subjected to a series of steps including standing, UV irradiation, cleaning, and drying. Subsequently, an organic electrolyte was coated onto the surface to obtain a zinc anode for an aqueous zinc-ion battery with a double-layer interface improvement.
[0037] Before coating the zinc sheet with polydimethylsiloxane, the zinc sheet needs to be pretreated. Specifically, the zinc sheet is rinsed with anhydrous ethanol and then dried before being coated with polydimethylsiloxane.
[0038] In a preferred embodiment, the amount of polydimethylsiloxane coating should be sufficient to ensure that the thickness of the final polydimethylsiloxane layer meets the relevant requirements.
[0039] Specifically, the settling time is 1 to 5 minutes.
[0040] The conditions for ultraviolet irradiation include: power of 20-30 W, wavelength of 250-340 nm, distance of 7-10 cm, and time of 30-40 min.
[0041] The distance for ultraviolet irradiation refers to the distance between the zinc sheet after it has been left to stand and the ultraviolet light source.
[0042] When performing polydimethylsiloxane graft modification on the zinc sheet surface, ultraviolet irradiation is crucial for achieving in-situ photo-initiated crosslinking and covalent grafting of the siloxane precursor, thus constructing a protective layer that firmly bonds to the zinc anode. Strict control of the ultraviolet irradiation time, power, and distance is essential to ensure sufficient grafting and appropriate crosslinking of the polydimethylsiloxane layer: insufficient irradiation leads to discontinuous protective layer and weak adhesion; excessive irradiation causes over-crosslinking and density, increasing interfacial impedance and hindering Zn absorption. 2+ Transmission. Suitable ultraviolet conditions are a prerequisite for obtaining a uniform, thin, dense polydimethylsiloxane layer with excellent ion conductivity.
[0043] Specifically, after UV irradiation, excess ungrafted PDMS was washed away with tetrahydrofuran, then washed three times with anhydrous ethanol, and finally dried.
[0044] The drying temperature is 60℃, and the drying time is only needed to dry the liquid.
[0045] The third aspect of this invention provides the application of the above-mentioned double-layer interface improved zinc anode in aqueous zinc-ion batteries in the preparation of aqueous zinc-ion batteries.
[0046] A fourth aspect of the present invention provides an aqueous zinc-ion battery, the aqueous zinc-ion battery comprising the above-mentioned double-layer interface-improved aqueous zinc-ion battery zinc anode and an aqueous electrolyte; The aqueous electrolyte is a zinc sulfate solution and / or a zinc chloride solution.
[0047] The aqueous zinc-ion battery in this invention can be either a symmetrical battery or an asymmetrical battery.
[0048] This invention grafts polydimethylsiloxane (PDMS) onto the surface of a zinc sheet to form a coating with a thickness on the nanometer scale. An organic electrolyte is then dropped onto the coating to achieve dual-interface control. This dual-interface layer aims to suppress zinc dendrite growth, isolate the zinc anode from direct contact with the electrolyte, and provide only ion channels. This invention effectively improves the calendar aging problem of the zinc anode and enhances the long-term cycle life of zinc-ion batteries.
[0049] The present invention will be described in detail below through embodiments. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods in the art.
[0050] The specifications and sources of the raw materials used in the following examples and comparative examples are as follows: 1. Polydimethylsiloxane: Purity: Viscosity 0.65 cSt (Manufacturer: Aladdin); 2. Trimethyl phosphate: Analytical grade AR (manufacturer: Yuanye); 3. N-methylformamide: Purity: 99% (Manufacturer: Sigma); 4. Tetrahydrofuran: Analytical grade AR (manufacturer: Aladdin); 5. Zinc trifluoromethanesulfonate: Purity: 98% (Manufacturer: Bide) 6. Zinc tetrafluoroborate: analytical grade CP (manufacturer: Aladdin); 7. Bacterial cellulose membrane: The bacterial cellulose membrane was placed in an 80℃ deionized water hot water bath for 30 min, then the deionized water was replaced, and the same hot water bath treatment was repeated 4 times until the bacterial cellulose membrane reached its maximum swelling degree. The bacterial cellulose membrane was then placed in a freeze dryer for freeze drying. The freeze-dried bacterial cellulose membrane was cut into 16 mm diameter discs. A portion of the 16 mm diameter bacterial cellulose membranes was immersed in a 2 mol / L ZnSO4 solution for 24 h to obtain ZnSO4 electrolyte bacterial cellulose membranes for later use; another portion of the 16 mm diameter bacterial cellulose membranes was immersed in a 4 mol / L ZnCl2 solution for 24 h to obtain ZnCl2 electrolyte bacterial cellulose membranes for later use.
[0051] Example 1 Zinc foil was rinsed with anhydrous ethanol and dried to obtain pretreated zinc sheets. Polydimethylsiloxane (PDMS) was coated onto the surface of the pretreated zinc sheets using a 150 mm scraper. After standing for 1 min, the sheets were irradiated with a 20 W UV lamp at a wavelength of 254 nm for 30 min at a distance of 7 cm. Excess PDMS was then washed away with tetrahydrofuran, followed by three rinses with anhydrous ethanol and drying in a vacuum oven at 60 °C to obtain zinc sheets with a PDMS coating (denoted as PDMS@Zn). 3.64 g of inorganic zinc salt (zinc trifluoromethanesulfonate) was weighed into a beaker, and 10 mL of trimethyl phosphate and 10 mL of N-methylformamide were added. The mixture was stirred with a magnetic stirrer until the solution became transparent, yielding an organic electrolyte with an inorganic zinc salt concentration of 0.5 mol / L. PDMS@Zn was then cut into 10 mm diameter pieces using a cutting machine. One piece, measuring approximately mm in size, is placed in the negative electrode shell. 5 μL of organic electrolyte is then added dropwise onto the PDMS@Zn sheet, forming an organic electrolyte layer. The ratio of the organic electrolyte volume to the zinc sheet area is 6.4 μL: 1 cm². 2 A double-layer interface improved zinc anode for an aqueous zinc-ion battery was obtained, denoted as PDMS@Zn-TMP:NMF. Then, a bacterial cellulose membrane containing ZnSO4 electrolyte was placed inside, ensuring that the side with the organic electrolyte added was in contact with the ZnSO4 electrolyte-bacterial cellulose membrane. Following the same procedure, 5 μL of organic electrolyte was added to another cut PDMS@Zn sheet. The ratio of organic electrolyte volume to zinc sheet area was 6.4 μL: 1 cm². 2Another zinc anode for an aqueous zinc-ion battery with improved double-layer interface was obtained. This zinc anode was placed on top of the ZnSO4 electrolyte bacterial cellulose membrane (the side with the organic electrolyte added also contacted the ZnSO4 electrolyte bacterial cellulose membrane). Then, a gasket and a spring were placed in place. Finally, the positive electrode shell was attached, and the battery was sealed using a battery packaging machine to obtain an aqueous zinc-ion symmetric button cell battery, marked as PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric cell. In this embodiment, the zinc anode of the aqueous zinc-ion battery with improved dual-layer interface includes a zinc sheet, on which a polydimethylsiloxane layer and an organic electrolyte layer are sequentially coated; the thickness of the polydimethylsiloxane layer is 30 nm.
[0052] Example 2 The method was implemented in accordance with Example 1, except that the inorganic zinc salt used was zinc tetrafluoroborate, and the concentration of the inorganic zinc salt in the organic electrolyte was 1 mol / L. The preparation method of this organic electrolyte was as follows: 2.39 g of zinc tetrafluoroborate was weighed into a beaker, 10 mL of trimethyl phosphate was added, and the mixture was stirred with a magnetic stirrer until the solution became transparent, thus obtaining an organic electrolyte with a zinc salt concentration of 1 mol / L.
[0053] Example 3 The procedure was carried out in accordance with Example 1, except that the ZnSO4 electrolyte bacterial cellulose membrane was replaced with a ZnCl2 electrolyte bacterial cellulose membrane; and finally, a PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric cell was obtained.
[0054] Example 4 The method was implemented in accordance with Example 1, except that a self-supporting iodine positive electrode was used instead of another double-layer interface improved zinc anode in the aqueous zinc-ion battery to obtain a zinc-iodine full cell, labeled as PDMS@Zn-TMP:NMF / / I2 full cell; The self-supported iodine cathode was prepared according to the method described in the literature "High-iodine-loading quasi-solid-state zinc–iodine batteries enabled by a continuous ion-transport network". The specific steps are as follows: Carrier preparation: Weigh 20 g of bacterial cellulose and add 20 mL of deionized water. Dilute the bacterial cellulose slurry by pulsed ultrasound and electromagnetic stirring. Add 160 mg of conductive carbon black and stir electromagnetically for 12 h to fully disperse the conductive carbon black. Continue to add 1.28 g of activated carbon and stir thoroughly for 48 h. Pour into a container and let it dry naturally. After it is fully dried, put it in a vacuum oven at 80 ℃ for 12 h to fully dry, and obtain the BC self-supporting carrier. Iodine loading: Take the BC self-supporting carrier, dry it, and cut it into original pieces with a diameter of 10 mm. Weigh and record the weight of each BC self-supporting carrier piece. Weigh iodine element with an iodine loading of 60% of the weight of the BC self-supporting carrier and put it into a small centrifuge tube together with the BC self-supporting carrier. Then place it in the inner liner of the reactor and replace it with high-purity argon gas in a glove box. Place the reactor in an 80 ℃ oven for 6 hours to obtain a self-supporting iodine cathode. Seal and store it properly for later use. The iodine loading is equal to the weight of the self-supporting iodine cathode obtained after iodine loading - the weight of the BC self-supporting carrier before iodine loading.
[0055] Comparative Example 1 Polish one side of the zinc sheet with 1500-grit sandpaper, then rinse it three times with ethanol. After drying, cut it into 10 mm diameter pieces using a cutting machine to obtain zinc electrode sheets. Place one zinc electrode sheet into the negative electrode shell, then place the ZnSO4 electrolyte bacterial cellulose membrane inside. Place the other zinc electrode sheet on top of the membrane, then add the gasket and spring sheet. Finally, close the positive electrode shell and seal the battery using a battery packaging machine to obtain a primitive zinc negative electrode aqueous zinc-ion symmetric button cell, labeled as a Zn / / Zn symmetric cell.
[0056] Comparative Example 2 The method was carried out in Comparative Example 1, except that the ZnSO4 electrolyte bacterial cellulose membrane was replaced with a ZnCl2 electrolyte bacterial cellulose membrane to obtain a Zn / / Zn symmetric cell.
[0057] Comparative Example 3 The method of Comparative Example 1 was followed, except that a self-supporting iodine positive electrode was used instead of another zinc electrode to obtain a zinc-iodine full cell, labeled as a Zn / / I2 full cell. The self-supporting iodine positive electrode was prepared according to the method of Example 4.
[0058] Test Example 1 A small amount (7 ml) of the organic electrolyte prepared in Example 1—a 0.5 mol / L Zn(OTf)₂ solution—was poured into a transparent glass bottle. A yellow oily staining agent was added to stain the solution, and the mixture was stirred thoroughly. Then, an equal volume of 2 mol / L ZnSO₄ solution was added. After standing for a period of time, the phenomenon was observed. Figure 2As shown in Figure a, the two are clearly separated into layers, with the lower yellow layer being a 0.5 mol / L Zn(OTf)2 solution and the upper transparent layer being a 2 mol / L ZnSO4 solution. Pour a small amount (7 ml) of the organic electrolyte prepared in Example 2—a 1 mol / L Zn(BF4)2 solution—into a transparent glass bottle. Add a red oily staining agent to stain it, stir well, and then add an equal volume of 2 mol / L ZnSO4 solution. After standing for a period of time, observe the phenomenon. Figure 2 As shown in Figure b, the two are clearly separated into layers. The lower red layer is a 1 mol / L Zn(BF4)2 solution, and the upper transparent layer is a 2 mol / L ZnSO4 solution.
[0059] It can be seen that both Zn(OTf)2 solution and Zn(BF4)2 solution meet the conditions for stratification with aqueous electrolyte and can form a dense protection for polydimethylsiloxane layer.
[0060] Test Example 2 The PDMS@Zn prepared in Example 1 was characterized using scanning electron microscopy, EDS spectroscopy, and X-ray photoelectron spectroscopy.
[0061] Scanning electron microscope (SEM) images and EDS images are as follows: Figure 3 As shown: the surface of the PDMS@Zn sheet is smooth without any bumps or depressions, and the EDS elements are evenly distributed. The characteristic elements C, O, and Si have significant signals, indicating that the PDMS layer is attached to the zinc sheet surface. XPS diagram as follows Figure 4 As shown: XPS test of PDMS@Zn shows the corresponding characteristic peaks, proving that the PDMS layer was successfully grafted onto the zinc sheet surface.
[0062] Test Example 3 The symmetric cells assembled in Examples 1-3 and the Zn / / Zn symmetric cells assembled in Comparative Examples 1-2 were placed under the same conditions for 5, 10, 15 and 20 days respectively. Then the cells were disassembled to observe the corrosion on the electrode surface and the results were compared by optical photography (optical photos were obtained directly by taking pictures with a camera), morphological inspection by scanning electron microscopy and X-ray diffraction (XRD).
[0063] Optical photographs of Example 1 and Comparative Example 1 are as follows: Figure 5 As shown, optical photographs of Example 3 and Comparative Example 2 are as follows. Figure 6As shown in the optical photographs, the symmetrical cells assembled with PDMS@Zn-TMP:NMF in Examples 1 and 3 still maintained good metallic luster after 20 days of rest. In contrast, the symmetrical cells assembled with Zn sheets in Comparative Examples 1 and 2 showed little metallic luster after 5 days of rest, and the zinc sheets were severely corroded after 15 and 20 days. The comparison of the optical photographs clearly demonstrates the significant anti-corrosion effect of PDMS@Zn-TMP:NMF on 2 mol / L ZnSO4 electrolyte and 4 mol / L ZnCl2 electrolyte.
[0064] Scanning electron microscope images of Example 1 and Comparative Example 1 are shown below. Figure 7 As shown, the scanning electron microscope images of Example 3 and Comparative Example 2 are as follows: Figure 8 As shown in the comparison images obtained by scanning electron microscopy, the symmetrical cells assembled by PDMS@Zn-TMP:NMF in Examples 1 and 3 remained smooth and flat on the electrode surface after 5, 10, 15, and 20 days of resting, with no obvious byproducts or corrosion pits. However, the symmetrical cells assembled by Zn sheets in Comparative Examples 1 and 2 showed that byproducts accumulated on the surface after 10, 15, and 20 days of resting. As the resting time increased, the byproducts gradually increased and corrosion pits formed.
[0065] The XRD patterns of Example 1 and Comparative Example 1 are as follows: Figure 9 As shown in Figure 1 (Figure a shows the XRD results of Comparative Example 1, and Figure b shows the XRD results of Example 1), the XRD patterns of Example 3 and Comparative Example 2 are as follows: Figure 10 As shown in Figure a (XRD results of Comparative Example 2, XRD results of Example 3): The XRD comparison charts show that the symmetrical cells assembled with PDMS@Zn-TMP:NMF in Examples 1 and 3 did not exhibit the peak of the corrosion byproduct (Zn(OH2)3)(ZnSO4)(H2O)5 at around 10°C after 5, 10, 15, and 20 days of resting. However, the symmetrical cells assembled with Zn sheets in Comparative Examples 1-2 showed the peak of the corrosion byproduct (Zn(OH2)3)(ZnSO4)(H2O)5 at around 10°C after 10, 15, and 20 days of resting, and the peak became more pronounced with increasing resting time. This further demonstrates that PDMS@Zn-TMP:NMF has a significant anti-corrosion effect on 2 mol / L ZnSO4 electrolyte and 4 mol / L ZnCl2 electrolyte.
[0066] The relevant test results of Example 2 are similar to those of Examples 1 and 3, indicating that the double-layer interface improved zinc anode of the aqueous zinc-ion battery of the present invention has a good anti-corrosion effect on both ZnSO4 electrolyte and ZnCl2 electrolyte.
[0067] Test Example 4 The PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric cells assembled in Example 1 and the Zn / / Zn symmetric cells assembled in Comparative Example 1 were subjected to the same conditions for resting for 5, 10, 15, and 20 days, respectively, and then at 2 mA cm⁻¹. -2 At current density and 2 mAh cm -2 Cyclic life tests were conducted at the specified capacity.
[0068] like Figure 11 As shown in Figure a, the cycle life of the Zn / / Zn symmetric battery gradually decreases with increasing resting time. After 5 days of rest, the cycle life is approximately 650 hours; after 10 days, it is approximately 600 hours; after 15 days, it is approximately 550 hours; and after 20 days, it is approximately 450 hours. Figure b shows the cycle life of the PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric battery. Compared with Comparative Example 1, the cycle life is significantly improved. After 5 days of rest, the cycle life is approximately 2500 hours; after 10 days, it is approximately 1800 hours; after 15 days, it is approximately 1800 hours; and after 20 days, it is approximately 1100 hours. It is evident that the anti-calendar aging ability of the aqueous zinc-ion battery of this invention is significantly improved, demonstrating a clear effect.
[0069] The PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric cells assembled in Example 3 and the Zn / / Zn symmetric cells assembled in Comparative Example 2 were subjected to resting periods of 5, 10, 15, and 20 days under the same conditions, respectively, and then subjected to a 2 mA cm⁻¹ test. -2 At current density and 2 mAh cm -2 Cyclic life tests were conducted at the specified capacity.
[0070] like Figure 12As shown in Figure a: Figure a presents the results of the Zn / / Zn symmetric battery. With increasing resting time, the long cycle life of the battery gradually decreases. After 5 days of rest, the cycle life is approximately 510 hours; after 10 days, approximately 450 hours; after 15 days, approximately 210 hours; and after 20 days, approximately 180 hours. Figure b presents the results of the PDMS@Zn-TMP:NMF / / PDMS@Zn-TMP:NMF symmetric battery. Compared with Comparative Example 2, the battery cycle life is significantly improved. After 5 days of rest, the cycle life is approximately 1700 hours; after 10 days, approximately 1600 hours; after 15 days, approximately 1400 hours; and after 20 days, approximately 1100 hours. Similarly, in a 4 mol / L ZnCl2 electrolyte system, the anti-calendar aging ability of the aqueous zinc-ion battery of this invention is also significantly improved.
[0071] The symmetrical battery of Example 2 was subjected to cycle life testing according to the same procedure. The results were similar to those of Examples 1 and 3. It can be seen that the calendar aging problem of the aqueous zinc-ion battery of the present invention is greatly improved in both the 2 mol / L ZnSO4 electrolyte system and the 4 mol / L ZnCl2 electrolyte system, which confirms that the PDMS layer and the organic electrolyte work together to significantly improve the corrosion problem of the zinc sheet.
[0072] Test Example 5 The full cells prepared in Example 4 and Comparative Example 3 were subjected to cycle life tests at a 2 C rate and a voltage range of 0.5 V to 1.6 V.
[0073] The cyclic results of Example 4 and Comparative Example 3 are as follows Figure 13 As shown: The zinc-iodine full cell assembled in Comparative Example 3 exhibited severe capacity decay in the first 50 cycles, with the final discharge capacity stabilizing at around 100 mAh / g; the zinc-iodine full cell assembled in Example 4 showed less capacity decay, retaining a discharge capacity of 180 mAh / g after 1000 cycles. The PDMS@Zn-TMP:NMF||I2 battery demonstrated superior performance, greater stability over long cycles, and higher capacity retention. PDMS@Zn-TMP:NMF effectively isolates the electrolyte from direct contact, mitigating corrosion and zinc dendrite formation, avoiding the consumption of zinc and iodine, and enhancing resistance to calendar aging.
[0074] It should be understood that any parts not described in detail in this specification belong to the prior art.
[0075] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A zinc anode for an aqueous zinc-ion battery with improved dual-layer interface, characterized in that, The dual-layer interface improves the zinc anode of an aqueous zinc-ion battery, which includes a zinc sheet covered with a polydimethylsiloxane layer and an organic electrolyte layer in sequence.
2. The zinc anode of an aqueous zinc-ion battery with improved dual-layer interface according to claim 1, characterized in that, The thickness of the polydimethylsiloxane layer is 30~50 nm.
3. The zinc anode of an aqueous zinc-ion battery with improved dual-layer interface according to claim 1 or 2, characterized in that, The raw material for the organic electrolyte layer is an organic electrolyte, which contains inorganic zinc salts and organic solvents. The concentration of inorganic zinc salt in the organic electrolyte is 0.5~1 mol / L.
4. The zinc anode of an aqueous zinc-ion battery with improved dual-layer interface according to claim 3, characterized in that, The inorganic zinc salt is zinc trifluoromethanesulfonate and / or zinc tetrafluoroborate; The organic solvent is N-methylformamide and / or trimethyl phosphate.
5. The zinc anode of an aqueous zinc-ion battery with improved dual-layer interface according to claim 3, characterized in that, The ratio of organic electrolyte volume to zinc sheet area is 3~7 μL: 1 cm². 2 .
6. The method for preparing the zinc anode of an aqueous zinc-ion battery with improved double-layer interface as described in any one of claims 1-5, characterized in that, include: Polydimethylsiloxane was coated onto the surface of a zinc sheet, which was then subjected to a series of steps including standing, UV irradiation, cleaning, and drying. Subsequently, an organic electrolyte was coated onto the surface to obtain a zinc anode for an aqueous zinc-ion battery with a double-layer interface improvement.
7. The preparation method according to claim 6, characterized in that, The settling time is 1 to 5 minutes.
8. The preparation method according to claim 6 or 7, characterized in that, The conditions for ultraviolet irradiation include: power of 20-30 W, wavelength of 250-340 nm, distance of 7-10 cm, and time of 30-40 min.
9. The application of the double-layer interface improved zinc anode of aqueous zinc-ion battery according to any one of claims 1-5 in the preparation of aqueous zinc-ion battery.
10. An aqueous zinc-ion battery, characterized in that, The aqueous zinc-ion battery includes the double-layer interface-improved aqueous zinc-ion battery zinc anode and aqueous electrolyte as described in any one of claims 1-5; The aqueous electrolyte is a zinc sulfate solution and / or a zinc chloride solution.