Zinc metal anodes with a textured zinc sulfide solid state electrolyte interface layer and methods of making the same

Abstract

The application discloses a zinc metal negative electrode with a textured zinc sulfide solid electrolyte interface layer and a preparation method thereof, and belongs to the technical field of zinc ion batteries. The negative electrode is composed of a cold-rolled zinc base and a zinc sulfide solid electrolyte interface layer. The zinc sulfide target material is bombarded by a high-energy laser beam to cause plasma state transformation and deposition on the cold-rolled zinc base. By controlling the deposition temperature and time, cavity gas pressure, laser frequency and power, a zinc sulfide solid electrolyte interface layer with a (111) texture strength higher than 2.5 and a layer thickness of 0.3-2.0 microns can be prepared, and a zinc metal negative electrode with the interface layer is obtained. In the aqueous zinc ion battery system, the negative electrode material exhibits a cycle service life of not less than 3400 times at a current density of 5 mA / cm 2 2, and a coulomb efficiency of 99.9%. The application is used for improving the cycle service life of zinc ion batteries, and has the advantages of simple and controllable process, high product stability and durability, non-toxic process, and greatly improved service life and reliability of commercial zinc ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of zinc-ion battery technology, and particularly relates to a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer and its preparation method. Background Technology

[0002] Aqueous zinc-ion batteries, with their advantages of low cost, high safety, environmental friendliness, and high volumetric energy density, have become highly promising energy storage devices in the "post-lithium battery era." However, uncontrollable dendrite growth and electrochemical corrosion reactions on the zinc metal anode surface limit its coulombic efficiency and cycle life, severely hindering the application of zinc-ion batteries. Notably, constructing an artificial solid-state electrolyte interface layer on the metal anode surface is considered an effective means to solve these problems. This strategy aims to regulate ion diffusion and nucleation, suppress dendrite growth, and mitigate corrosion reactions by physically isolating harmful reactions at the electrode / electrolyte interface, homogenizing ion diffusion, reshaping the surface electric field distribution, and providing strong mechanical support. This is expected to significantly improve the electrochemical reversibility and cycle life of zinc anodes. Therefore, developing a highly stable artificial solid-state electrolyte interface layer for zinc metal anodes has significant scientific value and strategic importance.

[0003] For an ideal solid electrolyte interface layer, in addition to electronic insulation properties, it should also possess excellent electrochemical activity and mechanical strength. Good electrochemical activity not only helps the uniform diffusion and nucleation of ions, but also inhibits hydrogen evolution and corrosion reactions; high mechanical strength can provide strong support to resist local stress concentration caused by dendrites and cause uniform plastic deformation. Zinc sphalerite phase zinc sulfide (ZnS) as a solid electrolyte interface layer for zinc metal anodes can meet the above requirements. Under normal conditions, ZnS has a stable crystal structure. However, different crystal microstructure characteristics will exhibit drastically different physicochemical properties. Density functional theory calculations show that the (111) crystal plane, as the electronegative sulfur atom close-packed plane of ZnS, is more conducive to controlling the adsorption, diffusion and nucleation of zinc ions than other crystal planes, thereby achieving uniform and ordered metal deposition behavior; at the same time, the ZnS (111) orientation has the highest elastic modulus and the lowest Schmidt factor, thus providing stronger mechanical support; in addition, the ZnS (111) crystal plane is more conducive to inhibiting electrochemical corrosion reactions. However, the ZnS produced by current mainstream methods for constructing artificial solid electrolyte interface layers (such as coating, in-situ chemical methods, and high-temperature gas-phase reaction methods) usually exists in a polycrystalline form. This forces a large number of amorphous (111) crystal planes to be exposed at the interface between the solid electrolyte interface layer and the electrolyte. The differences in electrochemical activity and mechanical strength between different crystal planes can easily lead to non-uniform nucleation of zinc ions and dendrite growth, which severely limits the cycle stability of the battery. Based on this, it is of great significance to develop a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer and its preparation method. The zinc metal anode comprises a cold-rolled zinc substrate and a zinc sulfide solid electrolyte interface layer. A textured zinc sulfide solid electrolyte interface layer is obtained on the surface of the cold-rolled zinc metal anode by bombarding a zinc sulfide target with a high-energy laser beam. This effectively suppresses the growth of zinc dendrites and the occurrence of electrochemical corrosion reactions during cycling. In an aqueous zinc-ion battery system, a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer is constructed. This zinc metal anode operates at 5 mA / cm². 2 It exhibits a cycle life of no less than 3400 cycles at current densities, with a coulomb efficiency of 99.9%.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The zinc metal anode with a textured zinc sulfide solid electrolyte interface layer uses rolled zinc metal with a cold working strain greater than 40% and a thickness of 50~200 μm as the anode substrate; the (111) texture strength of the zinc sulfide solid electrolyte interface layer is greater than 2.5 and the layer thickness is 0.3~2.0 μm.

[0006] The zinc metal anode is at 5 mA / cm 2 It exhibits a cycle life of no less than 3400 cycles at current densities, with a coulomb efficiency of 99.9%.

[0007] This invention provides a method for preparing a zinc metal anode material with a textured zinc sulfide solid electrolyte interface layer, comprising the following steps: 1) Low-temperature cold-rolled zinc metal to a reduction rate of more than 40%, and thinned to a specified thickness of 50~200 μm, is used as the negative electrode substrate; 2) The negative electrode substrate is sealed and fixed to the heating stage with high-temperature resistant silver paste, and then placed in a vacuum environment for high-temperature curing under pressure. The purpose of pressurization is to remove dissolved gases from the silver paste, and the purpose of high temperature is to accelerate the curing of the silver paste and ensure that residual organic solvents are fully volatilized to prevent cavity contamination. The heating stage is fixed in the ultra-vacuum reaction chamber, and the high-purity zinc sulfide target is fixed below the heating stage. Before deposition, the gas pressure in the reaction chamber is evacuated to 4×10⁻⁶. -8The process involves introducing high-purity argon gas into the cavity and simultaneously raising the temperature of the heating stage to 120–320 °C. During deposition, the heating stage and the target material are rotated at speeds of 1–5 rpm and 10–30 rpm, respectively. A 248 nm excimer KrF2 laser is activated, outputting pulsed laser light at a constant laser energy of 300–600 mJ. The pulse frequency is adjusted to 2–5 Hz, and the deposition time is controlled to be 30–160 min. The high-purity zinc sulfide target material is bombarded by the high-energy laser beam, causing it to undergo a plasma transformation and deposit onto the cold-rolled zinc substrate. After deposition, argon gas is introduced until the pressure in the ultra-vacuum reaction chamber reaches 1–20 Torr. The chamber is then held at the set temperature for 30–120 min before being cooled to room temperature. The silver paste adhesion area is removed, yielding a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer.

[0008] Preferably, the high-purity zinc sulfide target is fixed 5-10 cm below the heating stage to ensure the uniformity of the large-area film formation of the deposited layer. The crystal texture intensity of the deposited layer can be adjusted by controlling the target-substrate spacing.

[0009] Preferably, high-purity argon gas is introduced into the ultra-vacuum reaction chamber until the pressure reaches 3 × 10⁻⁶. -3 ~1.5×10 -1 Torr can inhibit the loss of sulfur and prevent the formation of sulfur vacancies during the deposition process, thereby ensuring the high chemical purity and structural integrity of the deposited layer.

[0010] Preferably, the heating stage temperature is increased from 2~10℃ / min to 120~320℃ to ensure sufficient thermal relaxation time for the zinc metal substrate to avoid thermal damage, while ensuring a high deposition rate and dense growth of the deposited layer.

[0011] Preferably, after holding at the set temperature for 30 to 120 minutes, the temperature is lowered to 20°C at a rate of 0.1 to 1°C / min to promote lattice rearrangement and densification of the deposited layer, effectively release the residual stress at the interface caused by the difference in thermal expansion coefficients, and prevent the deposited layer from cracking or peeling off.

[0012] The beneficial effects of this invention are as follows: This invention utilizes a laser beam bombardment method to synthesize in situ a zinc sulfide solid electrolyte interface layer with a strong (111) texture (texture strength higher than 2.5) on the surface of a cold-rolled zinc metal anode, thereby preparing a zinc anode material with high deposition / stripping reversibility and long cycle life. The strong (111) texture of zinc sulfide ensures that the closely packed (111) plane of strongly electronegative sulfur atoms participates in the zinc deposition regulation process as the main crystal plane, optimizing zinc ion adsorption, diffusion and nucleation, thereby achieving uniform and ordered metal deposition behavior. At the same time, the strong (111) texture has both the highest elastic modulus and the lowest Schmidt factor, which can provide stronger mechanical support and effectively suppress dendrite growth. In addition, the electrochemical corrosion reaction can also be significantly alleviated. In an aqueous zinc-ion battery system, the zinc metal anode with this interface layer can achieve a cycle life of 5 mA / cm 2 It exhibits a cycle life of no less than 3400 cycles at a given current density, with a coulombic efficiency of 99.9%. This invention is used to improve the cycle life of zinc-ion batteries. The process is simple and controllable, the product has high stability and durability, and the process is non-toxic, significantly improving the service life and reliability of commercial zinc-ion batteries. Attached Figure Description

[0013] Figure 1 This is a grazing incidence X-ray diffraction pattern of a zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in an embodiment of the present invention. Figure 2 The images show scanning electron microscope (SEM) images of the surface (a) and cross-section (b) of the zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in the embodiments of the present invention. Figure 3 This is a nanoindentation hardness diagram of a cold-rolled zinc metal anode and a zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in an embodiment of the present invention. Figure 4 The activation energy diagram of the reaction of the cold-rolled zinc metal anode and the zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in the embodiment of the present invention is shown. Figure 5 The Tafel curve of the cold-rolled zinc metal anode and the zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in the embodiment of the present invention is shown. Figure 6This is a cycle performance diagram of a cold-rolled zinc metal anode and a zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer in an embodiment of the present invention. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions herein are used to explain the invention but are not intended to limit it. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0015] This invention relates to a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer and its preparation method. The zinc metal anode consists of a cold-rolled zinc substrate and a zinc sulfide solid electrolyte interface layer. A zinc sulfide target is bombarded with a high-energy laser beam, causing it to undergo a plasma transformation and deposit onto the cold-rolled zinc substrate. By controlling the deposition temperature and time, cavity pressure, laser frequency, and power, a zinc sulfide solid electrolyte interface layer with a texture strength higher than 2.5 and a thickness of 0.3~2.0 μm can be prepared, resulting in a zinc metal anode with this interface layer. In an aqueous zinc-ion battery system, this anode material achieves a performance of 5 mA / cm². 2 It exhibits a cycle life of no less than 3400 cycles at current densities, with a coulomb efficiency of 99.9%.

[0016] Example 1 Low-temperature cold-rolled zinc metal was used to a reduction rate of 60% and the thickness reduced to 100 μm as the negative electrode substrate. The negative electrode substrate was sealed and fixed to the heating stage with high-temperature resistant silver paste, and then the heating stage was placed in a vacuum environment for high-temperature curing under pressure. The heating stage was fixed in an ultra-vacuum reaction chamber, and a high-purity zinc sulfide target was fixed 5 cm below the heating stage. Before deposition, the gas pressure in the reaction chamber was evacuated to 4 × 10⁻⁶. -8 Torr then introduced high-purity argon gas into the cavity until the internal pressure reached 1.5 × 10⁻⁶. -1 Torr, while heating the stage to 150℃ at 2℃ / min; during deposition, control the heating stage and target to rotate at 1 rpm and 10 rpm respectively; start the excimer KrF2 laser with a wavelength of 248 nm, output pulsed laser at a frequency of 2 Hz under a constant laser energy of 300 mJ, and control the deposition time to 120 min; after deposition, turn off the laser, introduce argon gas until the cavity pressure reaches 1.0 Torr, keep at 150℃ for 120 min and then reduce to 20℃ at 0.1℃ / min, cut off the silver paste adhesion area, and obtain the zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer.

[0017] Example 2 Low-temperature cold-rolled zinc metal was used to reduce the thickness to 100 μm with a reduction rate of 50%. This was then used as the negative electrode substrate. The substrate was sealed and fixed to a heating stage using high-temperature silver paste, followed by high-temperature curing under vacuum. The heating stage was then fixed within an ultra-vacuum reaction chamber, and a high-purity zinc sulfide target was fixed 8 cm below the heating stage. Before deposition, the gas pressure in the reaction chamber was evacuated to 4 × 10⁻⁶. -8 Torr then introduced high-purity argon gas into the cavity until the internal pressure reached 6.5 × 10⁻⁶. -2 Torr, while heating the stage to 240℃ at 6℃ / min; during deposition, control the heating stage and target to rotate at 3 rpm and 20 rpm respectively; start the excimer KrF2 laser with a wavelength of 248 nm, output pulsed laser at a frequency of 3 Hz under a constant laser energy of 520 mJ, and control the deposition time to 160 min; after deposition, turn off the laser, introduce argon gas until the cavity pressure reaches 10.0 Torr, keep at 240℃ for 30 min and then reduce to 20℃ at 0.5℃ / min, cut off the silver paste adhesion area, and obtain a zinc metal anode with a strong (111) texture (texture strength of 2.8) zinc sulfide solid electrolyte interface layer.

[0018] Example 3 Low-temperature cold-rolled zinc metal was used to reduce the thickness to 80 μm with a reduction rate of 42%. The negative electrode substrate was then sealed and fixed onto a heating stage using high-temperature resistant silver paste. The heating stage was then placed in a vacuum environment for high-temperature curing under pressure. The heating stage was fixed within an ultra-vacuum reaction chamber, and a high-purity zinc sulfide target was fixed 10 cm below the heating stage. Before deposition, the gas pressure in the reaction chamber was evacuated to 4 × 10⁻⁶. -8 Torr then introduced high-purity argon gas into the cavity until the internal pressure reached 3.0 × 10⁻⁶. -3 Torr, while heating the stage to 320℃ at 10℃ / min; during deposition, control the heating stage and target to rotate at 5 rpm and 30 rpm respectively; start the excimer KrF2 laser with a wavelength of 248 nm, output pulsed laser at a frequency of 5 Hz under a constant laser energy of 600 mJ, and control the deposition time to 30 min; after deposition, turn off the laser, introduce argon gas until the cavity pressure reaches 20.0 Torr, keep at 320℃ for 30 min and then reduce to 20℃ at 1℃ / min, cut off the silver paste adhesion area, and obtain a zinc metal anode with a strong (111) texture (texture strength of 2.6) zinc sulfide solid electrolyte interface layer.

[0019] like Figure 1The grazing incidence X-ray diffraction pattern of the zinc metal anode (Zn@ZnS_ST) with a zinc sulfide solid electrolyte interface layer having a strong (111) texture (texture intensity of 3.2) shows that Zn@ZnS_ST has an extremely strong (111) diffraction peak intensity and almost no other diffraction peaks belonging to zinc sulfide are observed, confirming that the artificial solid electrolyte layer of zinc sulfide constructed in Example 1 has a crystal microstructure feature with a strong (111) texture and a texture intensity of 3.2.

[0020] like Figure 2 Scanning electron microscope images of the surface (Figure a) and cross-section (Figure b) of the zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer show a highly dense ZnS grain distribution with uniform grain size, an average grain size of 60 nm, and a layer thickness of 1.5 μm.

[0021] like Figure 3 Nanoindentation hardness diagrams of zinc metal anodes (Zn@ZnS_ST) with strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer corresponding to cold-rolled zinc metal anodes show that the zinc sulfide interface layer with (111) texture strength of 3.2 exhibits extremely high hardness (~3.2 GPa) compared to cold-rolled zinc anodes. This is because the ZnS (111) orientation has the lowest Schmidt factor and the highest elastic modulus. This phenomenon indicates that the zinc sulfide solid electrolyte interface layer with strong (111) texture can provide better mechanical support to cope with the stress concentration distribution caused by dendrites and induce it to undergo planarization plastic deformation.

[0022] like Figure 4 The activation energy diagrams of the reaction of the corresponding cold-rolled zinc metal anode and the zinc metal anode with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer (Zn@ZnS_ST) are shown. The results indicate that the activation energy of the reaction of Zn@ZnS_ST is significantly reduced compared with that of the cold-rolled zinc anode, indicating that its electrochemical reaction activity is enhanced, thereby enabling more efficient and uniform metal deposition behavior.

[0023] like Figure 5 Tafel curves were plotted for a zinc metal anode with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer (Zn@ZnS_ST) corresponding to a cold-rolled zinc metal anode. The results show that compared with the cold-rolled zinc anode, Zn@ZnS_ST has a lower electrochemical corrosion current and a better corrosion potential, indicating its superior resistance to electrochemical corrosion.

[0024] A cold-rolled zinc metal anode and a zinc metal anode (Zn@ZnS_ST) with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer were cut into 12 mm diameter circular electrodes as anodes. A 2M ZnSO4 aqueous solution was used as electrolyte, a 12 mm diameter circular titanium electrode was used as positive electrode, and glass fiber was used as separator to assemble an asymmetric battery for cycle stability testing.

[0025] like Figure 6 The cycling performance diagram of the corresponding cold-rolled zinc metal anode and the zinc metal anode with a strong (111) texture (texture strength of 3.2) zinc sulfide solid electrolyte interface layer (Zn@ZnS_ST) shows that at a speed of up to 5 mA / cm², the performance is as follows: 2 At the specified current density, the Zn@ZnS_ST battery exhibited a cycle life of no less than 3400 cycles with a coulombic efficiency of 99.9%; in contrast, the battery with a cold-rolled zinc metal anode failed after only about 300 cycles. These phenomena confirm that a zinc sulfide interface layer with a strong (111) texture (texture strength of 3.2) can significantly enhance the cycle performance of the zinc anode, which is beneficial for promoting the application and commercialization of zinc-ion batteries.

[0026] The embodiments described above are merely preferred embodiments of the present invention and do not constitute a limitation on the scope of protection of this technical solution. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A zinc metal anode having a textured zinc sulfide solid electrolyte interface layer, characterized in that: Rolled zinc metal with a cold working strain greater than 40% and a thickness of 50~200 μm was used as the negative electrode substrate; the (111) texture strength of the zinc sulfide solid electrolyte interface layer was greater than 2.5 and the layer thickness was 0.3~2.0 μm.

2. The zinc metal anode with a textured zinc sulfide solid electrolyte interface layer according to claim 1, characterized in that: The zinc metal anode is at 5 mA / cm 2 It exhibits a cycle life of no less than 3400 cycles at current densities, with a coulomb efficiency of 99.9%.

3. The method for preparing a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer as described in claim 1 or 2, characterized in that, Includes the following steps: 1) Low-temperature cold-rolled zinc metal to a reduction rate of more than 40%, and thinned to a specified thickness of 50~200 μm, is used as the negative electrode substrate; 2) The negative electrode substrate is sealed and fixed on the heating stage with high-temperature resistant silver paste, and then placed in a vacuum environment for high-temperature curing under pressure; the heating stage is fixed in the ultra-vacuum reaction chamber, and the high-purity zinc sulfide target is fixed below the heating stage; Before deposition, the gas pressure in the ultra-vacuum reaction chamber was evacuated to 4 × 10⁻⁶. -8 The process involves introducing high-purity argon gas into the ultra-vacuum reaction chamber and simultaneously raising the temperature of the heating stage to 120–320 °C. During deposition, the heating stage and the high-purity zinc sulfide target are rotated at speeds of 1–5 rpm and 10–30 rpm, respectively. An excimer KrF2 laser with a wavelength of 248 nm is activated, outputting pulsed laser light at a constant laser energy of 300–600 mJ. The pulse frequency is adjusted to 2–5 Hz, and the deposition time is controlled to be 30–160 min. The high-purity zinc sulfide target is bombarded by the high-energy laser beam, causing it to undergo a plasma transformation and deposit onto the cold-rolled zinc substrate. After deposition, argon gas is introduced until the pressure in the ultra-vacuum reaction chamber reaches 1–20 Torr. The chamber is held at the set temperature for 30–120 min and then cooled to room temperature. The silver paste adhesion area is removed, yielding a zinc metal anode with a textured zinc sulfide solid electrolyte interface layer.

4. The preparation method according to claim 3, characterized in that: The high-purity zinc sulfide target is fixed 5-10 cm below the heating table.

5. The preparation method according to claim 3, characterized in that: High-purity argon gas was introduced into the ultra-vacuum reaction chamber until the pressure reached 3 × 10⁻⁶. -3 ~1.5×10 -1 Torr.

6. The preparation method according to claim 3, characterized in that: The temperature of the heating platform is increased to 120-320℃ at a rate of 2-10℃ / min.

7. The preparation method according to claim 3, characterized in that: After maintaining the temperature at the set temperature for 30-120 minutes, the temperature is lowered to 20℃ at a rate of 0.1-1℃ / min.

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