Oxygen-deficient nanomaterial, solid-phase melting zinc hot reduction preparation method and application thereof

Abstract

An oxygen-deficient nanomaterial, its solid-phase molten zinc thermal reduction preparation method, and its application. This invention uses zinc powder as a reducing agent. The target metal oxide, such as anatase TiO2, is uniformly mixed with zinc powder, followed by mild high-temperature annealing in an inert gas atmosphere. The product is then washed with dilute acid / alkali to obtain oxygen-deficient TiO2. 2‑x Nanomaterials. Similarly, oxygen-deficient SnO can be prepared using this method. 2‑x ZrO 2‑x and BaTiO 3‑x Materials. Compared to existing techniques for preparing oxygen-deficient nanomaterials, such as high-temperature hydrogen reduction, complex structure carbonization, and solvothermal reduction, this invention employs solid-phase molten zinc thermal reduction technology. Using environmentally friendly and low-cost zinc powder as a reducing agent, oxygen-deficient nanomaterials are prepared through a mild and high-temperature solid-phase molten zinc thermal reduction process. This method has no special requirements for production equipment, exhibits universal processing applicability and industrial production compatibility, and has successfully prepared a series of defect nanomaterials with adjustable oxygen defect concentrations. These nanomaterials have been applied to the negative electrode protection of zinc-ion batteries, effectively improving the cycle life of zinc batteries.

Description

Technical Field

[0001] This invention relates to the field of oxygen-deficient nanomaterial preparation technology, specifically to an oxygen-deficient nanomaterial, its solid-phase molten zinc thermal reduction preparation method, and its application. Background Technology

[0002] In recent years, renewable energy technologies such as wind power and solar power have developed rapidly. However, the distribution of these renewable energy sources is mostly limited by geographical location and seasonal factors, and there is an urgent need for efficient and new energy storage technologies to enable their effective output and utilization.

[0003] With its advantages of high energy density, high energy conversion efficiency, and no memory effect, lithium-ion battery technology is widely used in portable electronic devices and new energy vehicles. However, after deep cycling, lithium batteries are prone to lithium plating at the graphite negative electrode during overcharging, with dendrites piercing the separator and causing internal short circuits. Simultaneously, due to their high sensitivity to moisture, lithium batteries use organic electrolytes, which are prone to electrolyte decomposition and gas generation. Lithium dendrites further exacerbate these problems, generating significant heat and potentially leading to fires, explosions, and other serious safety accidents. In recent years, fires and explosions involving lithium-ion battery electric vehicles have been frequent, posing a serious safety challenge. On the other hand, global terrestrial lithium resources are limited and extremely unevenly distributed, and lithium resource extraction technology is demanding and costly, resulting in high costs for battery-grade lithium carbonate. Therefore, developing new high-efficiency energy storage technologies is of great scientific significance and application value.

[0004] Aqueous zinc-ion batteries possess high volumetric energy density and operational safety (no fire risk), making them a highly promising large-scale energy storage technology. Zinc metal, with its water stability, low electrode potential, and high hydrogen evolution barrier, is used as the anode material in many zinc-based battery technologies. However, in aqueous electrolytes, zinc metal anodes face severe challenges such as dendrite growth, hydrogen evolution side reactions, and interfacial byproduct deposition. Many oxide nanomaterials have been used for zinc anode interface modification, and oxygen-deficient nanomaterials can further reduce the zinc deposition barrier and improve its cycle life. However, current oxygen-deficient material preparation mainly relies on high-temperature hydrogen reduction, complex structure carbonization, and solvothermal reduction techniques, which are difficult to control in terms of defect introduction and large-scale supply, involve complex preparation processes, and pose safety risks. Therefore, developing efficient, universal, and scalable oxygen-deficient nanomaterial preparation technologies has significant scientific importance, broad application prospects, and economic value. Summary of the Invention

[0005] Technical problems to be solved: In view of the difficulties in controlling the introduction of defects and large-scale supply in the preparation process of oxygen defect materials in the existing technology, as well as the complexity of the preparation process and the safety risks, this invention proposes an oxygen defect nanomaterial, its preparation method of solid-phase molten zinc thermal reduction and its application. The preparation method is efficient, simple and universal. It adopts solvent-free solid-phase molten zinc thermal reduction technology, which can realize the preparation of oxygen defect nanomaterials with adjustable oxygen defect concentration. It can be used for surface protection of aqueous zinc metal anodes.

[0006] Technical solution: The first objective of this invention is to provide a solid-phase molten zinc thermal reduction method for preparing oxygen-deficient nanomaterials, the steps of which are as follows:

[0007] Step 1: Mix the transition metal oxide nanomaterials with zinc powder, place them in a ball mill jar, and add milling beads. The mass ratio of zinc powder to transition metal oxide nanomaterials is 0.5% to 200%.

[0008] Step 2: Add dispersant to the ball mill jar, seal the ball mill jar, and perform ball milling. The ratio of dispersant to powder mixture is 0.5-10 mL / g.

[0009] Step 3: Dry the ball-milled mixture and pulverize it;

[0010] Step 4: Place the transition metal oxide nanomaterial / zinc powder mixture in a crucible and heat it in a tube furnace under a protective atmosphere for 0.5 to 5 hours. The upper limit of the annealing temperature shall not exceed the phase transition temperature of the target defect oxide, which shall be determined by the species crystal form of the target defect oxide. The lower limit shall be higher than the melting point of zinc powder.

[0011] Step 5: The calcined product of the above transition metal oxide nanomaterial / zinc powder mixture is treated with sufficient 0.1-1.0M dilute acid or dilute alkali, and the treated product is centrifuged, washed with deionized water, and dried to obtain oxygen defect nanomaterial.

[0012] This invention involves ball milling and mixing transition metal oxide materials with reducing agent zinc powder, followed by inert annealing, and then acid / alkali washing of the final product to remove zinc and other impurities. It innovatively proposes a solid-phase molten zinc thermal reduction technology, and successfully prepares oxygen defect nanomaterials with adjustable oxygen defect concentration, which has important scientific significance, broad application prospects and economic value.

[0013] Preferably, the transition metal oxide nanomaterial in step one is TiO2, SnO2, ZrO2, or BaTiO3 powder, and the oxygen-deficient TiO3 is prepared accordingly in step five. 2-x SnO 2-x ZrO 2-x or BaTiO 3-x Nanomaterials.

[0014] Preferably, in step one, the mass ratio of zinc powder to TiO2 powder is 0.5% to 200%, the mass ratio of zinc powder to SnO2 powder is 0.5% to 110%, the mass ratio of zinc powder to ZrO2 powder is 0.5% to 130%, and the mass ratio of zinc powder to BaTiO3 powder is 0.5% to 100%.

[0015] Preferably, the dispersant in step two is at least one of ethanol, isopropanol, N,N-dimethylformamide (DMF), acetonitrile, and tetrahydrofuran (THF).

[0016] Preferably, in step two, the ball milling speed is 200-600 rpm, the rotation direction is forward or a combination of forward and reverse rotation, and the ball milling time is 1-72 h.

[0017] Preferably, the protective atmosphere in step four is at least one of nitrogen (N2), argon (Ar) and helium (He).

[0018] Preferably, the annealing temperature in step four is 420–550°C.

[0019] Preferably, in step five, the dilute acid is dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid, and the dilute alkali is dilute ammonia, sodium hydroxide, or potassium hydroxide solution.

[0020] Furthermore, in step five, zinc can be recovered and extracted by diluting the washing leachate, thus realizing the recycling of the reducing agent.

[0021] A second objective of this invention is to provide an oxygen-deficient nanomaterial prepared based on the above-described method.

[0022] A third objective of this invention is to provide the application of the aforementioned oxygen-deficient nanomaterial as a protective material for the negative electrode of an aqueous zinc-ion battery. This oxygen-deficient nanomaterial can be used as a protective material for the negative electrode of an aqueous zinc-ion battery, effectively improving the cycle life of the zinc battery.

[0023] Beneficial effects: (1) This invention provides a simple, controllable, universal and scalable mild solid-phase molten zinc thermal reduction technology to prepare oxygen defect nanomaterials. It uses environmentally friendly and low-cost zinc powder as a reducing agent, and uses zinc molten impregnation oxide under solvent-free, mild high temperature to remove surface oxygen atoms for reduction. The results were verified by electron paramagnetic resonance test, and a series of defect nanomaterials with adjustable oxygen defect concentration were successfully prepared. The oxygen defect nanomaterials prepared were used as metal anode protection materials for zinc-ion batteries, which effectively improved the cycle life of zinc batteries.

[0024] (2) Compared with existing commonly used oxygen defect material preparation technologies such as high-temperature hydrogen reduction, complex structure carbonization, and solvothermal reduction (which are difficult to introduce defects in a controllable manner, have complex preparation processes and safety risks), the solid-phase molten zinc thermal reduction technology reported in this invention prepares oxygen defect materials with a mild operating temperature, no special equipment requirements, and compatibility with existing industrial production technologies. It has good processing safety, industrial compatibility and production universality, and has broad application prospects and economic value.

[0025] (3) Zinc can be recovered and extracted by diluting the washing leachate, thus realizing the recycling of the reducing agent.

[0026] (4) The defect oxide nanomaterials proposed in this invention are also widely reported excellent catalyst materials that can be used in related fields such as catalysis, energy storage and environmental science, and have important scientific significance and application value. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 For a series of zinc thermal reduction TiO 2-x XRD patterns.

[0029] Figure 2 For a series of zinc thermal reduction TiO 2-x TEM images, where a is the initial TiO2 and b is the reduced TiO2. 2-x (10% Zn); c is reduced TiO 2-x (20% Zn); d represents reduced TiO2. 2-x (30% Zn).

[0030] Figure 3 For a series of zinc thermal reduction TiO 2-x The room temperature EPR spectrum.

[0031] Figure 4 Zinc thermal reduction of TiO 2-x The room temperature EPR spectrum of the controlled experimental sample.

[0032] Figure 5 Zinc thermal reduction of SnO 2-x (20% Zn), ZrO 2-x (20% Zn) and BaTiO 3-x XRD pattern of (20% Zn), where a in the figure represents zinc thermal reduction of SnO.2-x b represents zinc thermal reduction of ZrO. 2-x c represents zinc thermal reduction of BaTiO₂ 3-x .

[0033] Figure 6 SEM images of SnO2, ZrO2, and BaTiO3 before and after zinc thermal reduction treatment are shown. In the image, a represents initial SnO2; b represents initial ZrO2; c represents initial BaTiO3; and d represents SnO2 after zinc thermal reduction. 2-x e represents zinc thermal reduction ZrO 2-x f represents zinc thermal reduction of BaTiO₂ 3-x .

[0034] Figure 7 Zinc thermal reduction of SnO 2-x (20% Zn), ZrO 2-x (20% Zn) and BaTiO 3-x The room temperature EPR spectrum of (20% Zn), where a represents the zinc thermal reduction of SnO. 2-x b represents zinc thermal reduction of ZrO. 2-x c represents zinc thermal reduction of BaTiO₂ 3-x .

[0035] Figure 8 Zinc thermal reduction of TiO 2-x Symmetrical cells protecting the zinc metal anode at 1 mAh cm⁻¹ -2 Cyclic performance diagram under areal capacity conditions, where a represents TiO2. 2-x (30% Zn) Protect zinc foil at 5 mA cm -2 At current density; b is TiO 2-x (30% Zn) Protective zinc foil at 20 mA cm⁻¹ -2 Cyclic performance at current density was assessed using unprotected bare zinc foil as a control sample.

[0036] Figure 9 Zinc thermal reduction of SnO 2-x ZrO 2-x and BaTiO 3-x Symmetrical cells protecting the zinc anode at 20 mAcm -2 Current density and 1mAh cm -2 Cyclic performance diagram under areal capacity conditions, where a represents SnO. 2-x (20% Zn) protective zinc foil; b is ZrO 2-x (20% Zn) protective zinc foil; c is BaTiO 3-x (20% Zn) Protective zinc foil. Detailed Implementation

[0037] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Unless otherwise specified, all raw materials used in the examples in this specification are from commercially available products.

[0040] The zinc powder was purchased from Sinopharm Chemical Reagent Co., Ltd., with an initial particle size of 2-20 μm.

[0041] Anatase TiO2 powder was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with an initial particle size of ~60nm.

[0042] The tetragonal SnO2 powder was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with an initial particle size of 50-70 nm.

[0043] The monoclinic ZrO2 powder was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with an original particle size of ~200nm.

[0044] The tetragonal BaTiO3 powder was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with an original particle size of ~0.3-3μm;

[0045] The grinding beads are agate grinding beads with particle sizes of 5mm, 8mm and 10mm, used in a 2:1:1 ratio.

[0046] The zinc foil was purchased from Qinghe County Tengfeng Metal Materials Co., Ltd., and its thickness is 100μm.

[0047] Example 1

[0048] This embodiment provides an oxygen-deficient TiO₂ 2-x The specific steps for preparing nanomaterials are as follows:

[0049] Weigh 2g of anatase TiO2 powder and 0.2g of zinc powder (or 0.4g or 0.6g of zinc powder), mix them, and place them in a ball mill jar. Add agate beads and 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 400rpm for 20 hours in both forward and reverse directions. Place the ball-milled product in an oven and dry it at 60℃ to obtain a TiO2 / zinc powder mixture. Mechanically pulverize it, take an appropriate amount of the TiO2 / zinc powder ball-milled mixture, place it in a crucible, and anneal it in a high-temperature tube furnace at 500℃ for 2 hours under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 0.5M dilute hydrochloric acid for 1 hour, centrifuge, wash three times with deionized water, and dry to obtain oxygen-deficient titanium dioxide nanomaterials, denoted as TiO2. 2-x (10 / 20 / 30% Zn). Zinc can be recovered and extracted by diluting the washing leachate, thus achieving the recycling of the reducing agent.

[0050] A series of zinc thermal reduction TiO2 prepared 2-x See the XRD pattern. Figure 1 As can be seen from the figure, compared with the initial anatase TiO2 powder (denoted as initial TiO2 (0% Zn)), the prepared products all maintain the anatase crystal phase structure, indicating that the zinc thermal reduction process does not change the material nature and ensures that the prepared material maintains the target crystal form (the upper limit of the annealing temperature is determined according to the species crystal form of the target defect oxide prepared, and the lower limit should not be lower than the melting point of zinc powder).

[0051] A series of zinc thermal reduction TiO2 prepared 2-x See TEM image Figure 2 As can be seen from the figure, the obtained product still maintains the nanoparticle morphology of the initial TiO2 material, and no obvious secondary particle growth or particle sintering and agglomeration phenomenon has occurred.

[0052] A series of zinc thermal reduction TiO2 prepared 2-x See the room temperature EPR (electron paramagnetic test) spectrum. Figure 3 The results showed that the initial TiO2 material had no obvious oxygen vacancy signal, while the zinc-reduced TiO2 material... 2-x The (10 / 20 / 30% Zn) material exhibits a clear oxygen vacancy signal, and the oxygen vacancy signal increases with the increase of the zinc reducing agent ratio, indicating that the oxygen defect concentration is adjustable and controllable.

[0053] Comparative Example 1

[0054] Same as Example 1, except that no zinc powder is added, and no ball milling or pickling is performed.

[0055] Specifically, the initial anatase TiO2 powder was placed in a crucible and then placed in a high-temperature tube furnace. It was annealed at 500°C for 2 hours under a nitrogen atmosphere and then cooled to room temperature to obtain directly inert annealed TiO2 material, denoted as annealed TiO2 (0% Zn).

[0056] Comparative Example 2

[0057] Same as Example 1, except that no annealing process is performed.

[0058] The specific steps are as follows: Weigh 2g of anatase TiO2 powder and 0.6g of zinc powder, mix them, and place them in a ball mill jar; add agate beads, then add 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 400rpm in both forward and reverse directions for 20h; place the ball-milled product in an oven and dry it at 60℃ to obtain a TiO2 / zinc powder mixture. Mechanically pulverize it, treat it with sufficient 0.5M dilute hydrochloric acid for 1h, centrifuge, wash it three times with deionized water, and dry it to obtain the ball-milled acid-washed TiO2 (30% Zn, unannealed).

[0059] Zinc thermal reduction TiO2 prepared in Example 1 and Comparative Examples 1-2 2-x See the room temperature EPR spectrum of the controlled experimental samples. Figure 4 In Example 1, TiO was thermally reduced with zinc. 2-x Using 30% Zn as an example, the figure shows that under zinc powder-free conditions, the same inert atmosphere annealing process cannot introduce oxygen vacancies into TiO2; when using zinc powder for co-ball milling, direct acid washing without annealing also cannot introduce oxygen vacancies into TiO2. These results indicate that both the zinc powder reducing agent and the temperature-controlled annealing process are indispensable. Solid-state molten zinc thermal reduction is a complete process; only by combining both can TiO2 with adjustable and controllable oxygen vacancies concentration be prepared. 2-x Oxygen-deficient materials.

[0060] Example 2

[0061] This embodiment provides an oxygen-deficient SnO 2-x The specific steps for preparing nanomaterials are as follows:

[0062] Weigh 2g of tetragonal SnO2 powder and 0.4g of zinc powder, mix them, and place them in a ball mill jar. Add agate beads and 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 400rpm for 20 hours in both forward and reverse directions. Place the ball-milled product in an oven and dry it at 60℃ to obtain a SnO2 / zinc powder mixture. Powder it, take an appropriate amount of the SnO2 / zinc powder ball-milled mixture, place it in a crucible, put it in a high-temperature tube furnace, and anneal it at 500℃ for 2 hours under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 0.5M dilute hydrochloric acid for 1 hour, centrifuge, wash three times with deionized water, and dry to obtain the final product, denoted as SnO2.2-x (20% Zn).

[0063] Example 3

[0064] This embodiment provides an oxygen-deficient ZrO₂ 2-x The specific steps for preparing nanomaterials are as follows:

[0065] Weigh 2g of monoclinic ZrO2 powder and 0.4g of zinc powder, mix them, and place them in a ball mill jar. Add agate beads and 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 400rpm for 20 hours in both forward and reverse directions. Place the ball-milled product in an oven and dry it at 60℃ to obtain a SnO2 / zinc powder mixture. Powder the mixture, take an appropriate amount of the ZrO2 / zinc powder ball-milled mixture, place it in a crucible, and anneal it in a high-temperature tube furnace at 500℃ for 2 hours under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 0.5M dilute hydrochloric acid for 1 hour, centrifuge, wash three times with deionized water, and dry to obtain the final product, denoted as ZrO2. 2-x (20% Zn).

[0066] Example 4

[0067] This embodiment provides an oxygen-deficient BaTiO₂ 3-x The specific steps for preparing nanomaterials are as follows:

[0068] Weigh 2g of tetragonal BaTiO3 powder and 0.4g of zinc powder, mix them, and place them in a ball mill jar. Add agate beads and 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 400rpm for 20 hours in both forward and reverse directions. Place the ball-milled product in an oven and dry it at 60℃ to obtain a SnO2 / zinc powder mixture. Powder it, take an appropriate amount of the BaTiO3 / zinc powder ball-milled mixture, place it in a crucible, put it in a high-temperature tube furnace, and anneal it at 500℃ for 2 hours under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 0.5M dilute hydrochloric acid for 1 hour, centrifuge, wash three times with deionized water, and dry to obtain the final product, denoted as BaTiO3. 3-x (20% Zn).

[0069] like Figure 5 As shown, when SnO2, ZrO2 and BaTiO3 powders were subjected to zinc thermal reduction treatment, the resulting products still maintained the original material crystal form, and no obvious phase transformation was found.

[0070] SEM images of the relevant zinc thermal reduction products prepared in Examples 2-4 are shown below. Figure 6 Compared with the initial material, the heat treatment process did not cause significant particle size growth, and the resulting product was nanoscale in size.

[0071] Furthermore, such as Figure 7As shown, the room temperature electron paramagnetic test results of the products prepared in Examples 2-4 demonstrate that the solid-phase molten zinc thermal reduction technology successfully introduces stable oxygen defect structures in SnO2, ZrO2 and BaTiO3 materials, proving the processing effectiveness and universality of this method.

[0072] Example 5

[0073] This embodiment provides an oxygen-deficient TiO₂ 2-x The specific steps for preparing nanomaterials are as follows:

[0074] Weigh 2g of anatase TiO2 powder and 4g of zinc powder, mix them, and place them in a ball mill jar. Add agate beads and 60mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 200rpm in both forward and reverse directions for 72h. Place the ball-milled product in an oven and dry it at 60℃ to obtain a TiO2 / zinc powder mixture. Mechanically pulverize it, take an appropriate amount of the TiO2 / zinc powder ball-milled mixture, place it in a crucible, put it in a high-temperature tube furnace, and anneal it at 420℃ for 0.5h under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 1M dilute hydrochloric acid for 1h, centrifuge, wash three times with deionized water, and dry to obtain oxygen-deficient titanium dioxide nanomaterials.

[0075] Example 6

[0076] This embodiment provides an oxygen-deficient TiO₂ 2-x The specific steps for preparing nanomaterials are as follows:

[0077] Weigh 2g of anatase TiO2 powder and 0.01g of zinc powder, mix them, and place them in a ball mill jar. Add agate beads and 10mL of anhydrous ethanol, seal the ball mill jar, and ball mill at 600rpm for 1 hour in both forward and reverse directions. Place the ball-milled product in an oven and dry it at 60℃ to obtain a TiO2 / zinc powder mixture. Mechanically pulverize it, take an appropriate amount of the TiO2 / zinc powder ball-milled mixture, place it in a crucible, and anneal it in a high-temperature tube furnace at 550℃ for 5 hours under a nitrogen atmosphere. Cool to room temperature, treat the annealed product with sufficient 0.1M dilute hydrochloric acid for 1 hour, centrifuge, wash three times with deionized water, and dry to obtain oxygen-deficient titanium dioxide nanomaterials. Application Examples and Effect Verification:

[0078] The oxygen-deficient nanomaterials (TiO2) prepared 2-x (30% Zn), SnO 2-x (20% Zn), ZrO 2-x (20% Zn) or BaTiO 3-x(20% Zn), conductive carbon black Super P, and battery-grade polyvinylidene fluoride powder were mixed and ground evenly at a mass ratio of 8:1:1, and dispersed in methylpyrrolidone solvent at a solvent-to-powder ratio of 1–10 mL / g. The mixture was stirred to obtain an active material slurry. This slurry was then coated onto a commercial zinc foil surface, vacuum dried, and stamped to obtain a working electrode. This electrode was used to assemble a Zn-Zn symmetric battery (using a 1 mol / L ZnSO4 aqueous electrolyte and a glass fiber separator). Subsequently, the battery underwent constant current charge-discharge cycle testing using a Blue Battery testing system.

[0079] like Figure 8 As shown, compared to unmodified bare zinc foil, oxygen-deficient TiO₂... 2-x Zinc anodes modified with (30% Zn) material can effectively improve cycle stability and cycle life, and reduce their potential polarization. At 1 mAh cm⁻¹ -2 At surface capacity, respectively at 5mA cm -2 and 20mAcm -2 At the given current density, the cycle life of bare zinc foil symmetric cells is approximately 180 cycles and 325 cycles, respectively, while that of TiO2 cells is... 2-x The cycle life of the (30% Zn) protected zinc foil symmetric cells is approximately 1320 cycles and 3950 cycles, respectively.

[0080] like Figure 9 As shown, compared to unprotected bare zinc foil, SnO 2-x (20% Zn), ZrO 2-x (20% Zn) and BaTiO 3-x (20% Zn) and other additives can also effectively improve the cycle stability and cycle life of zinc electrodes at 20 mA / cm. -2 Current density and 1mAhcm -2 Under the surface capacity, SnO 2-x (20% Zn), ZrO 2-x (20% Zn) and BaTiO 3-x The cycle life of the (20% Zn) protected zinc foil symmetric cells was approximately 1640 cycles, 2380 cycles, and 775 cycles, respectively, demonstrating the effectiveness of the oxygen defect materials prepared by this method.

[0081] Given its small particle size, high oxygen defect concentration, and zinc affinity, among the several oxygen-deficient materials selected for modifying zinc anodes in the experiment, oxygen-deficient TiO₂ was the most suitable. 2-x (30% Zn) has the most significant effect on improving the cycle life of zinc anodes, and preferably, it can be used as an ideal zinc anode protection material.

[0082] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. The application of an oxygen-deficient nanomaterial as a negative electrode protection material for aqueous zinc-ion batteries, characterized in that, The oxygen-deficient nanomaterial is oxygen-deficient TiO₂. 2-x SnO 2-x ZrO 2-x or BaTiO 3-x The nanomaterials are prepared by solid-phase molten zinc thermal reduction, and the specific steps are as follows: Step 1: Mix the transition metal oxide nanomaterials with zinc powder, place the mixture in a ball mill jar, and add milling beads. The transition metal oxide nanomaterials are TiO2, SnO2, ZrO2, or BaTiO3 powders. TiO2, SnO2, ZrO2, and BaTiO3 powders are all commercially available products. The initial particle size of TiO2 powder is 60 nm, the initial particle size of SnO2 powder is 50-70 nm, and the initial particle size of ZrO2 powder is 200 nm. The mass ratio of zinc powder to TiO2 powder is 10%~30%, the mass ratio of zinc powder to SnO2 powder is 0.5%~110%, the mass ratio of zinc powder to ZrO2 powder is 0.5%~130%, and the mass ratio of zinc powder to BaTiO3 powder is 0.5%~100%. Step 2: Add dispersant to the ball mill jar, seal the ball mill jar, and perform ball milling. The ratio of dispersant to powder mixture is 0.5~10 mL / g. Step 3: Dry the ball-milled mixture and pulverize it; Step 4: Place the powdered material obtained in Step 3 into a crucible and heat it in a tube furnace under a protective atmosphere for 0.5 to 5 hours. The upper limit of the annealing temperature shall not exceed the phase transformation temperature of the target defect oxide to be prepared, and the lower limit shall be higher than the melting point of zinc powder. Step 5: Treat the calcined product obtained in Step 4 with sufficient 0.1~1.0 M dilute acid or dilute alkali, centrifuge the treated product, wash it with deionized water, and dry it to obtain oxygen-deficient TiO2. 2-x SnO 2-x ZrO 2-x or BaTiO 3-x Nanomaterials; wherein the oxygen defect concentration of the oxygen defect nanomaterial is controllably adjustable by adjusting the mass ratio of zinc powder to transition metal oxide nanomaterial in step one, and the oxygen defect concentration increases with the increase of the zinc powder ratio.

2. The application according to claim 1, characterized in that, The dispersant in step two is at least one of ethanol, isopropanol, N,N-dimethylformamide, acetonitrile, and tetrahydrofuran.

3. The application according to claim 1, characterized in that, In step two, the ball milling speed is 200-600 rpm, the rotation direction is forward or a combination of forward and reverse rotation, and the ball milling time is 1-72 h.

4. The application according to claim 1, characterized in that, In step four, the protective atmosphere is at least one of nitrogen, argon, and helium.

5. The application according to claim 1, characterized in that, The annealing temperature in step four is 420~550℃.

6. The application according to claim 1, characterized in that, In step five, the dilute acid is dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid, and the dilute alkali is dilute ammonia, sodium hydroxide, or potassium hydroxide solution.

Images