Preparation method of modified zinc anode, aqueous zinc ion battery

Abstract

The present disclosure relates to a preparation method of a modified zinc anode and an aqueous zinc-ion battery, and pertains to the technical field of aqueous zinc-ion batteries. The preparation method includes: S10. Patterning the surface of a zinc foil by using an ultraviolet picosecond pulsed laser to obtain a laser-reconstructed zinc anode; S20. Performing plasma treatment on the surface of the laser-reconstructed zinc anode by using a plasma technology to obtain a modified zinc anode. The preparation method provided by the present disclosure reduces the growth of zinc dendrites on the surface during the use of the modified zinc anode and the occurrence of side reactions at the zinc anode-electrolyte interface through the combined application of laser patterning treatment and plasma treatment, and the preparation process is simple and the cost is low.

Description

Technical Field

[0001] The present disclosure relates to the technical field of aqueous zinc-ion batteries, and in particular, to a method for preparing a modified zinc anode and an aqueous zinc-ion battery. Background Art

[0002] Aqueous zinc-ion batteries are regarded as a large-scale energy storage solution with great development potential due to their intrinsic safety, environmental friendliness, and cost advantages. Benefiting from the abundant natural reserves of metallic zinc (crustal abundance reaches 75 ppm), high theoretical specific capacity (820 mAh / g), and low redox potential (relative to the standard hydrogen electrode is -0.76 V), metallic zinc as the active material of the anode of aqueous zinc-ion batteries exhibits significant application value.

[0003] However, the core bottleneck restricting the large-scale application of aqueous zinc-ion batteries lies in the interfacial stability problem of zinc anode materials, which is specifically manifested in the following two dimensions:

[0004] Firstly, the surface integrity defects of commercial rolled zinc foils significantly affect the electrochemical performance. The industrial rolling process results in common technological defects such as microcracks, mechanical scratches, and unpolished edges on the surface of zinc electrodes. These micro-nano scale structures, as high-curvature active sites, will cause uneven distribution of zinc ion flux, accelerate the nucleation and growth of dendrites, and ultimately lead to internal short circuit and capacity attenuation of the battery.

[0005] Secondly, the insufficient dynamic wettability of the solid-liquid interface exacerbates side reactions. The contact angle between traditional zinc electrodes and electrolytes is relatively large (usually > 90°), and this interfacial non-wetting characteristic will lead to three chain effects: 1) significantly reduce the effective electrochemical active area, triggering the electrode passivation phenomenon; 2) promote the decomposition of H2O molecules at the interface, exacerbating the hydrogen evolution corrosion reaction; 3) induce local electric field distortion, forming a self-catalytic microenvironment for dendrite growth. Research data shows that the above interfacial failure mechanism can reduce the Coulombic efficiency of the battery to less than 85% after 50 cycles.

[0006] It should be noted that there is a strong coupling relationship between the zinc deposition morphology and the interfacial characteristics. The disordered dendrite growth not only causes the loss of active substances, but the accumulation of "dead zinc" caused by it will also lead to the volume expansion of the electrode, forming a vicious cycle. Therefore, constructing a stable zinc deposition / dissolution interfacial microenvironment has become the key scientific issue to promote the practical application process of aqueous zinc-ion batteries, and it is urgent to realize the synergistic optimization of zinc foil surface morphology regulation and interfacial chemical modification through surface engineering strategies.

[0007] At present, to solve the problem of dendritic growth of zinc anodes, the common treatment methods mainly include the following: (1) Surface functionalization coating technology; regulating zinc ion deposition kinetics by constructing an interfacial modification layer. In the article "An extended substrate screening strategy enabling a low lattice mismatch for highly reversible zinc anodes" published by the team of Zhou Guangmin at Tsinghua University in Nat. Commun. (Nature Communications 15, Article number: 753 (2024)), a layered vermiculite coating was used to optimize the electrolyte contact angle from 95° to 27°, and the directional transport of zinc ions was achieved by means of the confinement effect of two-dimensional nanochannels. In the article " In-situ grown hydrophilic-zinophilic ZnCr2O4protective layer to guide horizontal Zn 2+ deposition fordendrite -free Zn anodes for aqueous Zn-ion batteries" published by Lin et al. of Xichuan Normal University in Electrochim. Acta (Volume 470, December 1, 2023), by developing a ZnCr2O4 bifunctional interfacial layer, the wetting angle was reduced to 6.05°, and dense deposition was induced by a strong Zn² + adsorption energy (-3.12 eV). However, there are intrinsic defects in the technology in this article: 1) It is difficult to achieve sub-micron thickness uniformity by physical / chemical deposition methods; 2) The mismatch between the Young's modulus of the coating and the substrate (>5 GPa) leads to interfacial delamination under cyclic stress; 3) Dissolution of coating components during the formation of the dynamic SEI (such as Cr³ +The dissolution rate reaches 1.8 μg / cm² / cycle), which easily triggers secondary dendrite nucleation. (2) Three-dimensional structure engineering strategy: By designing a special zinc negative electrode structure, such as a three-dimensional porous structure, etc., to increase the contact area and achieve full contact between the electrode and the electrolyte, so as to improve the transmission and deposition of zinc ions. However, this method usually has a complex preparation process, high cost, and is difficult to mass-produce. The Chinese patent with the publication number CN117317118A discloses a scheme for realizing the B / C / N ternary co-permeation of Zn foil by using a 1064 nm nanosecond laser to construct a gradient doping layer, but the laser thermal effect (peak temperature > 1600 K) induces microcracks and ZnO phase transformation, making it difficult to carry out homogenized production. In the Chinese patent with the publication number CN115360317A, a scheme for laser engraving using a laser with a wavelength of 1064 nm to optimize the contact angle between the surface of the negative electrode of an aqueous zinc-ion battery and the electrolyte is disclosed. The current collector of its positive electrode is titanium foil, and the positive electrode active material is V2O5. Similarly, although the 1064 nm red light band can pattern and uniformly reconstruct the interface, the thermal effect of the heat source will change the chemical properties of the zinc metal surface, possibly causing excessive ablation and damaging the structural integrity and stability of the negative electrode. Generally speaking, although the existing zinc negative electrode treatment methods have improved the electrochemical performance of the zinc negative electrode to a certain extent, there are still many deficiencies. The modification methods only delay rather than block dendrite nucleation, fail to reconstruct the interfacial double-layer structure and eliminate local electric field distortion, and cannot fundamentally solve problems such as dendrite growth, low Coulomb efficiency, and poor cycle performance.

[0008] It should be noted that the information disclosed in the above background art section is only used to strengthen the understanding of the background of the present disclosure, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0009] The purpose of the present disclosure is to overcome the above-mentioned deficiencies of the prior art, and provide a preparation method for a modified zinc negative electrode and an aqueous zinc-ion battery. By the combined application of laser patterning treatment and plasma treatment, the growth of zinc dendrites on the surface during the use of the modified zinc negative electrode and the occurrence of side reactions at the zinc negative electrode - electrolyte interface are reduced.

[0010] According to one aspect of the present disclosure, a preparation method for a modified zinc negative electrode is provided, including the following steps:

[0011] S10. Perform patterning treatment on the surface of a zinc foil using an ultraviolet picosecond pulsed laser to obtain a laser-reconstructed zinc negative electrode;

[0012] S20. Perform plasma treatment on the surface of the laser-reconstructed zinc negative electrode using plasma technology to obtain a modified zinc negative electrode.

[0013] In an exemplary embodiment of the present disclosure, in step S10, the patterning process is to directly write a laser on the surface of the zinc foil;

[0014] The processing speed of the laser direct writing is 1000 - 2000 mm / s, the linear filling pitch is 0.005 mm - 0.01 mm, the linear filling angle is 0 - 90°, and the linear filling times are 1 - 10 times.

[0015] In an exemplary embodiment of the present disclosure, the processing speed of the laser direct writing is 1200 - 1600 mm / s, the linear filling pitch is 0.005 mm - 0.007 mm, the filling angle is 30 - 60°, and the filling times are 2 - 4 times.

[0016] In an exemplary embodiment of the present disclosure, the wavelength of the laser is 355 nm;

[0017] The actual power used by the laser is 1 - 5 W, and the maximum average power of the laser is 10 - 30 W.

[0018] In an exemplary embodiment of the present disclosure, in the laser direct writing, the angle between the laser head of the laser and the surface of the zinc foil is 90°.

[0019] In an exemplary embodiment of the present disclosure, the pattern obtained by the patterning process is a striped pattern or a dot matrix pattern.

[0020] In an exemplary embodiment of the present disclosure, in step S20, the working gas used in the plasma treatment is at least one of helium, argon, oxygen, nitrogen, hydrogen, carbon dioxide, chlorine, xenon, and water vapor.

[0021] In an exemplary embodiment of the present disclosure, the gas purity of the working gas is greater than or equal to 99.99%.

[0022] In an exemplary embodiment of the present disclosure, in step S20, the plasma treatment process includes:

[0023] The first stage: The gas flow rate is in the range of 10 - 80 sccm, the gas vacuum degree is in the range of 10 Pa - 30 Pa, the radio frequency power is in the range of 50 W - 200 W, and the treatment time is ≥100 s;

[0024] The second stage: The gas flow rate is in the range of 80 - 200 sccm, the gas vacuum degree is in the range of 30 Pa - 50 Pa, the radio frequency power is in the range of 200 W - 300 W, and the treatment time is ≥100 s.

[0025] According to another aspect of the present disclosure, there is provided an aqueous zinc-ion battery, and the negative electrode of the aqueous zinc-ion battery uses the modified zinc negative electrode prepared by the above preparation method.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0028] Figure 1 It is a flowchart of the preparation method of the modified zinc negative electrode in an embodiment of the present disclosure.

[0029] Figure 2 It is a comparative diagram of optical microscope characterization before and after the surface of zinc foil is patterned by laser in an embodiment of the present disclosure; wherein, (a) is the optical microscope characterization diagram before the surface of zinc foil is patterned by laser, and (b) is the optical microscope characterization diagram after the surface of zinc foil is patterned by laser.

[0030] Figure 3 It is a schematic diagram of the contact angle comparison between the surface of zinc foil and the electrolyte before laser treatment, after laser treatment, and after laser treatment combined with plasma treatment in an embodiment of the present disclosure; wherein, (a) is the contact angle characterization diagram of the surface of zinc foil and the electrolyte before laser treatment; (b) is the contact angle characterization diagram of the surface of zinc foil and the electrolyte after laser treatment; (c) is the contact angle characterization diagram of zinc foil and the electrolyte after laser treatment combined with plasma treatment.

[0031] Figure 4 It is a SEM characterization diagram of the surface of the zinc negative electrode after 100 charge-discharge cycles of the commercial metal zinc foil symmetric battery in the comparative example.

[0032] Figure 5 It is a SEM characterization diagram of the surface of the zinc negative electrode after 100 charge-discharge cycles of the modified zinc negative electrode electrode 1 symmetric battery obtained in Example 1.

[0033] Figure 6 It is a nucleation overpotential characterization diagram of the commercial metal zinc foil symmetric battery, the laser-reconstructed zinc negative electrode 1 symmetric battery in Example 1, and the modified zinc negative electrode electrode 1 symmetric battery in the comparative example. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0035] The terms "a", "an", "the", "said", and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.; the terms "first", "second", etc. are used only as labels and are not a limitation on the quantity of their objects.

[0036] An embodiment of the present disclosure provides a method for preparing a modified zinc negative electrode, and the modified zinc negative electrode can be used as the negative electrode of an aqueous zinc ion battery. As Figure 1 shown, the method for preparing the modified zinc negative electrode includes the following steps:

[0037] S10. Pattern the surface of the zinc foil with an ultraviolet picosecond pulsed laser to obtain a laser-reconstructed zinc negative electrode;

[0038] S20. Perform plasma treatment on the surface of the laser-reconstructed zinc negative electrode by using plasma technology to obtain a modified zinc negative electrode.

[0039] In step S10, as Figure 2 shown in (b) of [], perform laser treatment on the surface of the zinc foil with an ultraviolet picosecond pulsed laser to reduce the adverse effects of inherent defects such as microcracks, scratches, folding lines, and unpolished edges generated during the preparation of the zinc foil (as Figure 2 shown in (a) of []), and improve the surface stability and uniformity of the zinc foil when used as the negative electrode of the battery. At the same time, laser treatment is used to form nanoscale grooves and protrusions on the surface of the zinc foil, so that the surface texture of the zinc negative electrode is reconstructed, and then the preferred orientation of the interface (zinc negative electrode - electrolyte interface) formed by the contact between the surface of the zinc negative electrode and the electrolyte is reduced, thereby avoiding the growth of zinc dendrites on the surface of the zinc negative electrode. In addition, through laser treatment, the specific surface area of the zinc negative electrode is further increased, the active sites on the surface of the zinc negative electrode are increased, and more and uniform "anchor points" for the nucleation and deposition of zinc ions are provided, thereby improving the electrochemical performance of the aqueous zinc ion battery.

[0040] After reconstructing the texture characterization on the surface of the zinc anode by laser treatment, a laser-reconstructed zinc anode is formed. It is found in the experiment that when the electrolyte is dropped on the surface of the laser-reconstructed zinc anode, as shown in (a) and (b) of Figure 3 , the contact angle after laser treatment becomes larger compared with that before laser treatment, and the contact angle increases from 94.3° to 142.7°. However, it is also found in the experiment that when the electrolyte is dropped again at the position where the electrolyte has contacted (the area wetted by the electrolyte), the electrolyte can spread quickly, that is, the electrolyte can be evenly distributed on the surface of the laser-reconstructed zinc anode quickly. Based on this, in step S20, by performing plasma treatment on the surface of the laser-reconstructed zinc anode, the plasma can homogenize the electric field distribution at the zinc anode-electrolyte interface and can also form polar functional groups on the surface of the zinc anode, thereby improving the contact at the zinc anode-electrolyte interface. As shown in (c) of Figure 3 , the contact angle after the combination of laser treatment and plasma treatment decreases to 53.2°.

[0041] In this embodiment, the interface layer of the zinc anode (the surface where the zinc anode contacts the electrolyte) is reconstructed by laser treatment, and the texture on the interface layer of the zinc anode is optimized, which greatly reduces the preferred orientation conducive to the formation of dendrite growth and optimizes the zinc anode structurally to reduce dendrite growth. At the same time, on the basis of the structural optimization, the interface double-layer structure formed at the zinc anode-electrolyte interface is homogenized by plasma treatment, realizing the reconstruction of the interface double-layer structure. While further suppressing the growth of zinc dendrites and reducing side reactions, polar functional groups are introduced to increase the wettability of the electrolyte and the zinc anode interface, further improving the uniformity of zinc deposition, thereby reducing the generation of dendrites. Moreover, the preparation process of the modified zinc anode provided in this embodiment is simple and the manufacturing cost is low, which is beneficial to industrial production applications.

[0042] Optionally, the zinc foil can be a commercial zinc foil, which is the negative electrode of a water-based zinc-ion battery in the related art. In this way, the commercial zinc foil can be directly modified, and without affecting the original production line, the zinc foil can be modified to improve its performance as a zinc anode, reducing the production cost.

[0043] In an embodiment of the present disclosure, in step S10, the patterning process is to perform direct laser writing on the surface of the zinc foil using a laser; the processing speed of the direct laser writing is 1000-2000 mm / s, the linear filling pitch is 0.005 mm-0.01 mm, the linear filling angle is 0-90°, and the number of linear filling times is 1-10 times. In this embodiment, by limiting the processing speed, linear filling pitch, filling angle, and filling times in the direct laser writing. Combined with the plasma treatment process in step S20, uniform zinc deposition on the zinc negative electrode - electrolyte interface is achieved, and the growth of zinc dendrites on the zinc negative electrode during use is reduced.

[0044] In this embodiment, the processing speed of the direct laser writing is 1000-2000 mm / s. If the processing speed is too fast, the grooves formed on the surface of the zinc foil are shallower and cannot achieve the effect of modifying the texture of the zinc foil surface; if the processing speed is too slow, the grooves formed on the surface of the zinc foil are deeper. At the same time, slow processing will cause heat accumulation, resulting in ablation damage to the local area of the zinc foil and introducing an amorphous region, and the introduction of the amorphous region will hinder the chemical modification efficiency of the subsequent plasma. Thus, a suitable direct laser writing processing speed is required to obtain deeper grooves on the surface of the zinc foil to increase the unit contact area between the subsequent plasma and the zinc foil surface, promote the uniform growth of the oxide layer, and at the same time avoid ablation on the surface of the zinc foil by the direct laser writing, which affects the chemical modification treatment of the plasma. For example, the processing speed of the direct laser writing can be 1000 mm / s, 1100 mm / s, 1200 mm / s, 1300 mm / s, 1400 mm / s, 1500 mm / s, 1600 mm / s, 1700 mm / s, 1800 mm / s, 1900 mm / s or 2000 mm / s.

[0045] In this embodiment, the linear filling pitch is 0.005 mm-0.01 mm. This is because the linear filling pitch of the direct laser writing is related to the density of the etching pattern formed on the final zinc foil. When the linear filling pitch is small (for example, less than 0.01 mm), continuous grooves can be formed, increasing the specific surface area of the zinc foil, thereby increasing the active sites on the surface of the zinc foil and also enhancing the efficiency of grafting functional groups of the plasma gas on the surface of the zinc foil in the subsequent plasma treatment. However, on the one hand, if the linear filling pitch is too small, the formed etching pattern is too dense, which will limit the subsequent plasma treatment efficiency, and the plasma is difficult to penetrate to the bottom of the groove structure, resulting in uneven modification of the zinc negative electrode and affecting the uniform deposition of zinc, and instead is prone to the growth of zinc dendrites. On the other hand, if the linear filling pitch is too large, isolated structures may be formed on the surface of the zinc foil, thereby reducing the electrical performance of the zinc negative electrode in the overall structure. For example, the linear filling pitch can be 0.005 mm, 0.006 mm, 0.007 mm, 0.008 mm, 0.009 mm or 0.010 mm.

[0046] In this embodiment, the linear filling angle is 0 to 90°. Different linear filling angles in laser direct writing result in different texture patterns formed on the zinc foil surface, which in turn affects the distribution of plasma in the grooves during the subsequent plasma treatment process, and affects the efficiency and distribution uniformity of grafted functional groups. For example, the linear filling angle can be 0°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 50°, 65°, 50°, 75°, 80°, 85°, or 90°.

[0047] In this embodiment, the number of linear filling times is 1 to 10 times. Multiple linear fillings can obtain deeper grooves and form a layered structure during multiple fillings. The formed layered structure may enhance the residence time of the plasma and promote the formation of grafted functional groups in the deep layer of the grooves. However, too many filling times will form more cracks, introduce nucleation points for zinc dendrites, and increase the possibility of zinc dendrite growth. For example, the number of linear filling times can be 1 time, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, or 10 times.

[0048] That is to say, the laser direct writing parameters provided in the embodiments of the present disclosure need to cooperate with each other and synergistically interact with the subsequent plasma treatment to prepare a modified zinc negative electrode with an optimized surface structure and a reconstructed electric double layer structure at the zinc negative electrode - electrolyte interface, realizing the optimization of the zinc negative electrode from multiple aspects such as texture, electric double layer structure, and chemical functional groups, thereby reducing the growth of zinc dendrites during use and reducing the occurrence of side reactions on the zinc negative electrode.

[0049] Furthermore, the processing speed of the laser direct writing is 1200 to 1600 mm / s, the linear filling spacing is 0.005 mm to 0.007 mm, the filling angle is 30 to 60°, and the filling times are 2 to 4 times.

[0050] Preferably, the processing speed is 1500 mm / s, the linear filling spacing is 0.005 mm, the filling angle is 45°, and the filling times are 2 times.

[0051] In an embodiment of the present disclosure, the wavelength of the laser is 355 nm; the actual power of the laser used is 1 - 5 W, and the maximum average power of the laser is 10 - 30 W; the pulse width is less than 15 ps. That is to say, ultraviolet light with a wavelength of 355 nm is used. Ultraviolet light is also called a cold light source. During the laser direct writing process, the risk of ablation on the surface of the zinc foil is relatively small. During laser direct writing, the actual power of the laser used is 1 - 5 W. For example, the actual power used can be 1.0 W, 1.5 W, 2.0 W, 2.7 W, 3 W, 3.6 W, 4 W, 4.2 W, 4.8 W, or 5 W. To ensure the accuracy of the power, the maximum average power of the laser used is 10 - 30 W. For example, the maximum average power of the laser can be 10 W, 15 W, 20 W, 25 W, or 30 W. For example, when the maximum average power of the laser is 30 W, the actual power of the laser used is 9% of the maximum average power of the laser, that is, 2.7 W.

[0052] In one example, the pulse frequency range of the laser is 1 Hz - 2000 kHz, the power stability of the laser is less than 3%, the minimum focused spot is less than or equal to 9 μm, the beam quality M2 value is less than 1.2, the beam divergence angle is less than 2 mrad, and the spot roundness is greater than or equal to 90%. Exemplarily, the actual pulse frequency range of the laser used is 600 kHz - 2000 kHz. In this way, within this range, it not only avoids ablation on the surface of the zinc foil but also improves the processing accuracy and processing efficiency of laser direct writing.

[0053] In an embodiment of the present disclosure, during the laser direct writing, the angle between the laser head of the laser and the surface of the zinc foil is 90°. That is to say, the angle between the laser beam and the surface of the zinc foil is 90°. In this way, when the laser beam irradiates perpendicular to the surface of the zinc foil, the laser energy can be absorbed by the zinc foil to the greatest extent, and it is beneficial to the relatively uniform distribution of the laser energy on the surface of the zinc foil, avoiding unevenness in the depth or width of the processed pattern. At the same time, when the laser beam is perpendicular to the surface of the zinc foil, the focal position of the laser beam can be more easily and accurately controlled on the surface of the zinc foil, reducing spot distortion and improving processing accuracy.

[0054] In an embodiment of the present disclosure, the pattern obtained by the patterning process is a striped pattern. Exemplarily, grooves and protrusions arranged in an array are formed on the surface of the laser - reconstructed zinc negative electrode. Perpendicular to the extending direction of the grooves, the width dimension of the grooves is not greater than 1000 nm; perpendicular to the extending direction of the protrusions, the width dimension of the protrusions is not greater than 1000 nm.

[0055] In one embodiment of the present disclosure, the pattern obtained by the patterning process is a dot matrix pattern. In one embodiment, a cross-filling method can be adopted to obtain a dot matrix pattern. Exemplarily, grooves and protrusions arranged in an array are formed on the surface of the laser-reconstructed zinc anode. Perpendicular to the extending direction of the grooves, the width dimension of the grooves is not greater than 1000 nm. Exemplarily, the protrusions can be rectangles, rhombuses, etc. Among them, the short side dimension of the rectangle is not greater than 1000 nm; among the diagonals of the rhombus, the shorter diagonal dimension is not greater than 1000 nm.

[0056] In one embodiment of the present disclosure, in step S20, the working gas used for the plasma treatment is at least one of helium (He), argon (Ar), oxygen (O2), nitrogen (N2), hydrogen (H2), carbon dioxide (CO2), chlorine (Cl2), xenon (Xe), and water vapor (H2O). For example, using oxygen for plasma treatment can directly introduce functional polar groups such as hydroxyl (-OH) and carboxyl (-COOH) on the surface of the zinc foil. These polar groups interact with the components in the electrolyte, which can not only assist in inducing the stable and uniform dissolution and deposition of zinc ions at the active sites in the patterned array, avoiding the disordered formation and growth of zinc dendrites, but also effectively reduce the decomposition of water in the electrolyte on the surface of the zinc anode and the occurrence of other side reactions, thereby improving the capacity retention rate and cycle life of the aqueous zinc-ion battery. For another example, argon plasma treatment can also activate the surface of the zinc foil. Argon plasma can generate free radicals on the surface through physical bombardment and chemical action. These free radicals may react with oxygen in the air to indirectly form some oxygen-containing functional groups (such as polar groups like hydroxyl and carboxyl).

[0057] Exemplarily, the gas purity of the working gas is greater than or equal to 99.99%.

[0058] In one embodiment of the present disclosure, in step S20, the plasma treatment process includes: The first stage: the gas flow rate range is 10 - 80 sccm (standard cubic centimeters per minute), the gas vacuum degree range is 10 Pa - 30 Pa, the radio frequency power is 50 W - 200 W, and the treatment time ≥ 100 s; The second stage: the gas flow rate range is 80 - 200 sccm, the gas vacuum degree range is 30 Pa - 50 Pa, the radio frequency power is 200 W - 300 W, and the treatment time ≥ 100 s. In the first stage, it is possible to achieve preliminary cleaning and preliminary modification of the surface of the laser-reconstructed zinc anode, further removing the attached contaminants, oxides or residues on the surface, and at the same time introducing some active sites or functional groups that change the surface chemical properties. In the second stage, through plasma treatment, in-depth surface modification is carried out, functional groups are grafted uniformly on the surface, and the interfacial double-layer structure on the surface of the zinc anode is reconstructed.

[0059] The embodiments of the present disclosure also provide an aqueous zinc-ion battery, and the negative electrode of the aqueous zinc-ion battery uses the modified zinc negative electrode obtained by the above preparation method.

[0060] The following further illustrates the preparation method and performance of the negative electrode of the aqueous zinc-ion battery of the present disclosure in conjunction with specific embodiments.

[0061] In the embodiment provided by the present invention, the commercial zinc foil is purchased from Dongguan Kelude New Energy Technology Co., Ltd.

[0062] Comparative Example

[0063] The commercial zinc foil is cut into a zinc negative electrode with a diameter of 14 mm, and the assembled aqueous zinc-ion symmetric battery is a commercial metal zinc foil symmetric battery (Zn / Zn). Among them, the electrolyte is 1 mol L -1 aqueous zinc sulfate solution, and qualitative filter paper is used as the separator.

[0064] Using the commercial metal zinc foil symmetric battery (Zn / Zn), the charge-discharge cycle test is carried out under the conditions of a current density of 1 mA·cm -2 and a capacity cut-off of 0.5 mAh·cm -2 . After 156 cycles, the commercial metal zinc foil symmetric battery (Zn / Zn) short-circuits. As Figure 6 shown, during the charge-discharge cycle test, the average nucleation overpotential of the commercial metal zinc foil symmetric battery (Zn / Zn) is measured to be 170 mV.

[0065] Example 1

[0066] Step S10: Pattern the surface of the zinc foil by using an ultraviolet picosecond pulsed laser to obtain a laser-reconstructed zinc negative electrode. The following operations are included:

[0067] S101: Place the commercial zinc foil on the vacuum adsorption platform at the bottom of the laser, use an Advantech industrial computer to control for calibration, move the zinc foil, and then control the laser to perform laser direct writing on the surface of the zinc foil. Among them, the included angle between the laser head of the laser and the surface of the zinc foil is 90°.

[0068] The parameters for laser direct writing on the surface of commercial zinc foil by the laser are as follows: the laser wavelength is 355 nm, the selected laser direct writing area is multiple circular areas with a diameter of 14 mm, the maximum average power of the laser is 30 W, and the actual power used is 9% of the maximum average power of the laser (that is, the actual power used is 2.7 W). The pulse width is adjusted to 10 ps, and the pulse frequency is 700 kHz; the laser power stability is 1%, the minimum focused spot is 2 μm, and the spot roundness is 95%. The processing speed of laser direct writing is 1500 mm / s, the linear filling pitch is 0.005 mm, the linear filling angle is 45 degrees, and the number of linear filling times is 2 times.

[0069] S102. Cut the zinc foil after laser direct writing into circular electrodes with a diameter of 14 mm. The processing speed of laser cutting is 1000 mm / s, the laser power stability of laser cutting is 30%, the pulse frequency of laser cutting is 700 kHz, and the laser-reconstructed zinc negative electrode obtained is defined as laser-reconstructed zinc negative electrode 1 (L-Zn-1).

[0070] S20. Perform plasma treatment on the commercially available metallic zinc foil after laser etching using plasma technology. This step includes the following operations:

[0071] Place the laser-reconstructed surface of the laser-reconstructed zinc negative electrode obtained in step S102 face up in the plasma instrument, with 10 electrodes placed in each layer; the working gas used is oxygen (O2) with a purity of 99.99%.

[0072] The first stage: During the plasma treatment, the gas flow rate is set at 50 sccm, the vacuum degree is 30 Pa, the radio frequency power is 200 W, and the treatment time is 200 s. The second stage: Set the gas flow rate at 100 sccm, the vacuum degree at 40 Pa, the radio frequency power at 300 W, and the treatment time at 200 s. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment is defined as modified zinc negative electrode 1 (PL-Zn-1).

[0073] Assemble the laser-reconstructed zinc negative electrode 1 (L-Zn-1) obtained in step S102 into an aqueous zinc ion symmetric battery, and name it laser-reconstructed zinc negative electrode 1 symmetric battery (L-Zn-1 / L-Zn-1); among them, the electrolyte is 1 mol L -1 aqueous zinc sulfate solution, and qualitative filter paper is used as the separator.

[0074] Assemble the modified zinc negative electrode 1 (PL-Zn-1) obtained in step S20 into an aqueous zinc ion symmetric battery, and name it modified zinc negative electrode 1 symmetric battery (PL-Zn-1 / PL-Zn-1); among them, the electrolyte is 1 mol L -1 aqueous zinc sulfate solution, and qualitative filter paper is used as the separator.

[0075] The laser-reconstructed zinc anode 1 symmetric battery (L-Zn-1 / L-Zn-1) and the modified zinc anode electrode 1 symmetric battery (PL-Zn-1 / PL-Zn-1) were respectively used to carry out charge-discharge cycle tests under the conditions of a current density of 1 mA·cm -2 , and a capacity cut-off of 0.5 mAh·cm -2 . The laser-reconstructed zinc anode 1 symmetric battery (L-Zn-1 / L-Zn-1) short-circuited after 470 cycles; the modified zinc anode electrode 1 symmetric battery (PL-Zn-1 / PL-Zn-1) short-circuited after 661 cycles. Compared with the comparative example, the charge-discharge cycle number (470 times) of the L-Zn-1 / L-Zn-1 symmetric battery was significantly increased compared with that of the Zn / Zn symmetric battery (156 times); at the same time, the charge-discharge cycle number (661 times) of the PL-Zn-1 / PL-Zn-1 symmetric battery after oxygen plasma treatment was further improved. It shows that the modified zinc anode obtained by the preparation method provided in Example 1 greatly improves the cycle performance of the symmetric battery through laser direct writing and plasma treatment.

[0076] At the same time, the nucleation overpotential of the laser-reconstructed zinc anode 1 symmetric battery (L-Zn-1 / L-Zn-1) and the modified zinc anode electrode 1 symmetric battery (PL-Zn-1 / PL-Zn-1) was detected. As Figure 6 shown, the average nucleation overpotential of the L-Zn-1 / L-Zn-1 symmetric battery was 49 mV; the average nucleation overpotential of the PL-Zn-1 / PL-Zn-1 symmetric battery was 35 mV. Compared with the average nucleation overpotential (170 mV) of the Zn / Zn symmetric battery in the comparative example, the nucleation overpotentials of the L-Zn-1 / L-Zn-1 symmetric battery and the PL-Zn-1 / PL-Zn-1 symmetric battery were significantly reduced. Among them, the average nucleation overpotential of the PL-Zn-1 / PL-Zn-1 symmetric battery was less than that of the L-Zn-1 / L-Zn-1 symmetric battery. That is to say, the modified zinc anode obtained through laser direct writing and plasma treatment forms a symmetric battery with small energy loss during charge and discharge, and higher battery efficiency; at the same time, the smaller nucleation overpotential helps the zinc to grow uniformly, further reducing the formation of zinc dendrites, thereby improving the cycle stability and safety of the battery and prolonging the cycle life of the battery.

[0077] As Figure 4 shown, it is a schematic SEM (Scanning Electron Microscope) diagram of the surface of the zinc anode of the commercial metal zinc foil symmetric battery (Zn / Zn) in the comparative example after 100 charge-discharge cycles. From Figure 4It can be seen that the zinc deposition on the surface of the zinc anode is uneven, and there are obviously many zinc dendrites growing. The existence of zinc dendrites increases the nucleation overpotential, and the increase in nucleation overpotential further promotes the growth of zinc dendrites, ultimately causing the Zn / Zn symmetric battery to short-circuit after 156 cycles. As Figure 5 shown, it is the SEM schematic diagram of the surface of the zinc anode of the PL-Zn-1 / PL-Zn-1 symmetric battery in Example 1 after 100 charge-discharge cycles. Compared with Figure 4 that, the zinc deposition on the surface of the zinc anode of the PL-Zn-1 / PL-Zn-1 symmetric battery is uniform, and there are only a small amount of zinc dendrites. Thus, the nucleation overpotential of the PL-Zn-1 / PL-Zn-1 symmetric battery is small, and the small nucleation overpotential avoids the induction of dendrite formation, thereby improving the cycle performance of the battery.

[0078] Example 2

[0079] The difference between Example 2 and Example 1 is that in step S101, the processing speed of laser direct writing is 1200 mm / s, the linear filling spacing is 0.009 mm, the linear filling angle is 60 degrees, the linear filling times is 1 time, and the actual power used by the laser is 1 W.

[0080] In step S20, in the plasma treatment, in the first stage: the gas flow rate during the plasma treatment is set at 60 sccm, the vacuum degree is 20 Pa, and the radio frequency power is 100 W; in the second stage: the gas flow rate is set at 120 sccm, the vacuum degree is 50 Pa, and the radio frequency power is 220 W. The laser-reconstructed zinc anode treated by oxygen plasma prepared in this example is defined as the modified zinc anode 2 (PL-Zn-2).

[0081] The modified zinc anode 2 (PL-Zn-2) electrode is assembled into a symmetric battery, and charge-discharge cycle detection is carried out under the same conditions as in Example 1. The PL-Zn-2 / PL-Zn-2 symmetric battery short-circuits after 654 cycles.

[0082] Example 3

[0083] The difference between Example 3 and Example 1 is that in step S101, the processing speed of laser direct writing is 1600 mm / s, the linear filling spacing is 0.007 mm, the linear filling angle is 30 degrees, the linear filling times is 5 times, and the actual power used by the laser is 2 W.

[0084] In step S20, during plasma treatment, the first stage: the gas flow rate during plasma treatment is set at 40 sccm, the vacuum degree is 25 Pa, and the radio frequency power is 50 W; the second stage: the gas flow rate is set at 90 sccm, the vacuum degree is 45 Pa, and the radio frequency power is 200 W. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment in this example is defined as the modified zinc negative electrode 3 (PL-Zn-3).

[0085] The modified zinc negative electrode 3 (PL-Zn-3) electrode was assembled into a symmetric battery, and charge-discharge cycle testing was carried out under the same conditions as in Example 1. The PL-Zn-3 / PL-Zn3 symmetric battery short-circuited after 632 cycles.

[0086] Example 4

[0087] The difference between Example 4 and Example 1 is that in step S101, the processing speed of laser direct writing is 1400 mm / s, the linear filling pitch is 0.006 mm, the linear filling angle is 0 degrees, the number of linear filling times is 4 times, and the actual power used by the laser is 3 W.

[0088] In step S20, during plasma treatment, the first stage: the gas flow rate during plasma treatment is set at 80 sccm, the vacuum degree is 20 Pa, and the radio frequency power is 150 W; the second stage: the gas flow rate is set at 130 sccm, the vacuum degree is 40 Pa, and the radio frequency power is 280 W. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment in this example is defined as the modified zinc negative electrode 4 (PL-Zn-4).

[0089] The modified zinc negative electrode 4 (PL-Zn-4) electrode was assembled into a symmetric battery, and charge-discharge cycle testing was carried out under the same conditions as in Example 1. The PL-Zn-4 / PL-Zn-4 symmetric battery short-circuited after 644 cycles.

[0090] Example 5

[0091] The difference between Example 5 and Example 1 is that in step S101, the processing speed of laser direct writing is 1800 mm / s, the linear filling pitch is 0.005 mm, the linear filling angle is 90 degrees, the number of linear filling times is 10 times, and the actual power used by the laser is 5 W.

[0092] In step S20, during plasma treatment, the first stage: the gas flow rate during plasma treatment is set at 30 sccm, the vacuum degree is 15 Pa, and the radio frequency power is 120 W; the second stage: the gas flow rate is set at 80 sccm, the vacuum degree is 30 Pa, and the radio frequency power is 250 W. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment in this example is defined as the modified zinc negative electrode 5 (PL-Zn-5).

[0093] The modified zinc negative electrode 5 (PL-Zn-5) electrode was assembled into a symmetric battery, and charge-discharge cycle tests were carried out under the same conditions as in Example 1. The PL-Zn-5 / PL-Zn-5 symmetric battery short-circuited after 635 cycles.

[0094] Example 6

[0095] The difference between Example 6 and Example 1 is that in step S101, the processing speed of laser direct writing is 1000 mm / s, the linear filling pitch is 0.008 mm, the linear filling angle is 70 degrees, the number of linear filling times is 8 times, and the actual power used by the laser is 4 W.

[0096] In step S20, during the plasma treatment, in the first stage: the gas flow rate during the plasma treatment is set at 10 sccm, the vacuum degree is 10 Pa, and the radio frequency power is 180 W; in the second stage: the gas flow rate is set at 180 sccm, the vacuum degree is 35 Pa, and the radio frequency power is 270 W. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment in this example is defined as the modified zinc negative electrode 6 (PL-Zn-6).

[0097] The modified zinc negative electrode 6 (PL-Zn-6) electrode was assembled into a symmetric battery, and charge-discharge cycle tests were carried out under the same conditions as in Example 1. The PL-Zn-6 / PL-Zn-6 symmetric battery short-circuited after 637 cycles.

[0098] Example 7

[0099] The difference between Example 7 and Example 1 is that in step S101, the processing speed of laser direct writing is 2000 mm / s, the linear filling pitch is 0.010 mm, the linear filling angle is 80 degrees, the number of linear filling times is 6 times, and the actual power used by the laser is 3.5 W.

[0100] In step S20, during the plasma treatment, in the first stage: the gas flow rate during the plasma treatment is set at 70 sccm, the vacuum degree is 30 Pa, and the radio frequency power is 130 W; in the second stage: the gas flow rate is set at 200 sccm, the vacuum degree is 40 Pa, and the radio frequency power is 290 W. The laser-reconstructed zinc negative electrode obtained by oxygen plasma treatment in this example is defined as the modified zinc negative electrode 7 (PL-Zn-7).

[0101] The modified zinc negative electrode 7 (PL-Zn-7) electrode was assembled into a symmetric battery, and charge-discharge cycle tests were carried out under the same conditions as in Example 1. The PL-Zn-7 / PL-Zn-7 symmetric battery short-circuited after 620 cycles.

[0102] It should be noted that although the steps of the method for preparing the modified zinc negative electrode in the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and / or one step may be decomposed into multiple steps for execution, etc.

[0103] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not disclosed in the present disclosure.

Claims

1. A method for preparing a modified zinc negative electrode, characterized in that: The following steps are involved: S10, patterning the surface of the zinc foil using an ultraviolet picosecond pulse laser to obtain a laser reconstructed zinc negative electrode; the patterning process is to use a laser to directly write the surface of the zinc foil; the processing speed of the laser direct writing is 1000~2000mm / s, the straight line filling spacing is 0.005mm~0.01mm, the straight line filling angle is 0~90°, and the number of straight line fillings is 1~10 times; the actual power used by the laser is 1~5W; S20. Using plasma technology to perform plasma treatment on the surface of the laser reconstructed zinc negative electrode to obtain a modified zinc negative electrode; the contact angle of the modified zinc negative electrode is 53.2°; the working gas used in the plasma treatment is at least one of helium, argon, oxygen, nitrogen, hydrogen, carbon dioxide, chlorine, xenon, and water vapor.

2. The method for preparing the modified zinc negative electrode according to claim 1, characterized in that: The processing speed of the laser direct writing is 1200-1600 mm / s, the straight line filling spacing is 0.005 mm-0.007 mm, the straight line filling angle is 30-60°, and the number of straight line filling times is 2-4 times.

3. The method for preparing the modified zinc negative electrode according to claim 2, characterized in that: The wavelength of the laser is 355nm; The maximum average power of the laser is 10~30W.

4. The method for preparing the modified zinc negative electrode according to claim 2, characterized in that: In the laser direct writing, the angle between the laser head of the laser and the surface of the zinc foil is 90°.

5. The method for preparing a modified zinc negative electrode according to any one of claims 1 to 4, characterized in that: The pattern obtained by the patterning process is a stripe pattern or a dot pattern.

6. The method for preparing a modified zinc negative electrode according to claim 1, characterized in that: The gas purity of the working gas is greater than or equal to 99.99%.

7. The method for preparing a modified zinc negative electrode according to claim 1 or 6, characterized in that: In step S20, the plasma treatment process includes: The first stage: the gas flow rate is in the range of 10-80sccm, the gas vacuum is in the range of 10Pa-30Pa, the RF power is in the range of 50W-200W, and the processing time is ≥100s; The second stage: the gas flow rate is in the range of 80 to 200 sccm, the gas vacuum is in the range of 30 Pa to 50 Pa, the RF power is in the range of 200 W to 300 W, and the processing time is ≥100 s.

8. An aqueous zinc ion battery, characterized in that: The negative electrode of the aqueous zinc ion battery is a modified zinc negative electrode prepared by the preparation method described in any one of claims 1 to 7.

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