A multi-doped-ammonium intercalated vanadium oxide material, its preparation method and use

Abstract

The present application relates to a kind of poly-doped-ammonium intercalation vanadium oxide material and its preparation method and purposes, the preparation method includes the following steps: (1) the alkali leaching solution of sodium calcined vanadium residue is added to desilication agent and carries out desilication reaction, obtains desilication leaching solution;(2) the desilication leaching solution in step (1) is added to ammonium salt and carries out precipitation reaction, obtains precursor;(3) the precursor in step (2) is sequentially carried out drying treatment, calcination treatment, and the poly-doped-ammonium intercalation vanadium oxide material is prepared.The preparation process of the present application reduces the requirement for vanadium species purity in preparation process on the one hand by using the alkali leaching solution of vanadium residue as raw material, on the other hand, the associated excellent impurities therein serve as a doping source for the preparation process, making the preparation process more simplified, and the zinc ion battery prepared from the obtained vanadium oxide material has excellent electrochemical performance.

Description

Technical Field

[0001] This invention relates to the field of energy storage materials technology, and in particular to a multi-doped ammonium intercalated vanadium oxide material, its preparation method, and its applications. Background Technology

[0002] Vanadium oxides, due to their unique electrochemical reversibility, high theoretical capacity, and the ability of multiple oxidation states to participate in charge transfer reactions, have become highly promising electrode materials in energy storage devices such as sodium-ion batteries, aqueous zinc-ion batteries, and supercapacitors. However, their practical application is limited by several factors, such as poor conductivity and short cycle life. Doping technology improves the electrochemical performance of vanadium oxides by introducing metallic or non-metallic dopants into the vanadium oxide lattice, mainly by improving conductivity, enhancing structural stability, and optimizing ion diffusion. Pre-intercalation technology, by intercalating vanadium oxide layers to increase the interlayer spacing and facilitate zinc ion diffusion, is also an effective improvement method. To date, in the preparation of doped or intercalated modified vanadium oxide materials, the vanadium source is mostly a chemically pure vanadium compound reagent, and the dopants and intercalating agents are mostly high-purity chemicals. High synthesis costs and raw material expenses restrict its further development as an energy storage material. Literature reports mainly focus on the study of single dopant ions, but research on multi-component and synergistic doping systems is lacking.

[0003] Si-yuan Zhang et al. reported the use of chemically pure vanadium and doped calcium sources in constructing vanadium oxide electrode materials (see Zhang SY, Lang LM, Hu YJ, et al. Strong Lewis electron-pair bonding in vanadium oxide for ultra-fast and long-term stable Zn-ionstorage[J]. Energy Storage Materials, 2024). Qi-jian Li et al. reported the preparation of cobalt-doped vanadium pentoxide hollow microspheres using a vanadium-based metal-organic framework as a template, synthesized via hydrothermal and calcination methods, using chemically pure reagents, resulting in high synthesis consumption (see Li QJ, Wei F X. Co doped V2O5 Hollow Microsphere as High-performance Cathode for Aqueous Zinc-ion Battery[J]. Journal of PowerSources, 2025).

[0004] Prior art CN114050256A discloses a metal-doped vanadium-based oxide nanomaterial, its preparation method, and its applications. The chemical formula of this nanomaterial is M. x V5O 12 Where M is any one of magnesium, manganese, cobalt, and nickel, and 0.005≤x≤0.03, the preparation method of metal-doped vanadium-based oxide nanomaterials includes the following steps: dissolving V₂O₅ and oxalic acid in a solvent to obtain precursor solution A; adding a dopant M-based salt to precursor solution A to obtain precursor solution B; and adding precursor solution B to an alcohol solvent to carry out a solvothermal reaction. This scheme uses chemically pure vanadium pentoxide as the vanadium source, and the dopant M-based salt is a commercially available raw material. Its preparation process is relatively complex and costly.

[0005] Although the above methods provide some ways to prepare doped modified vanadium oxide energy storage materials, the preparation process still has problems such as the need to use chemically pure vanadium salts, the complexity of the preparation process, the high cost, and the low and unstable capacity of the product. Therefore, it is still of great significance to develop a low-cost preparation method that combines the advantages of doping and intercalation to prepare modified vanadium oxides. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a multi-component doped ammonium intercalated vanadium oxide material, its preparation method, and its applications. The method uses a sodium-calcined alkaline leaching solution of vanadium slag as the raw material, thereby reducing the purity requirements of vanadium and lowering the cost of the preparation process. Simultaneously, impurity elements such as chromium, calcium, and potassium ions in the leaching solution can serve as natural dopant sources to improve the conductivity of vanadium oxides, eliminating the need for high-purity chemicals as dopant sources. The ammonium ions of the vanadium-precipitating intermediate ammonium metavanadate are used as intercalating agents to prepare vanadium oxides with large interlayer spacing.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a multi-component doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Add a desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out a desilication reaction, and obtain a desilication leachate; (2) Add ammonium salt to the desilication leachate obtained in step (1) to carry out a precipitation reaction, and obtain the precursor by solid-liquid separation; (3) The precursor described in step (2) is subjected to drying and calcination treatment in sequence to prepare the multi-doped ammonium intercalated vanadium oxide material.

[0008] This invention uses an alkaline leaching solution of vanadium slag (sodium-calcined) as the raw material, thereby reducing the purity requirements of vanadium and lowering the cost of the preparation process. A precipitation method is employed, where ammonium salts are added to the desilication leaching solution to produce a precipitate, which is then calcined to obtain the multi-element doped-ammonium intercalated vanadium oxide material. The calcination method used in this invention retains the ammonium ions in the precursor as intercalation ions. This invention simplifies the preparation process by using an alkaline leaching solution of vanadium slag as the raw material, reducing the purity requirements of the vanadium species, and by utilizing the associated high-quality impurities as doping sources.

[0009] In this invention, the alkaline leachate of the sodium-roasted vanadium slag is an alkaline vanadium-containing solution obtained by leaching (usually water leaching) the vanadium slag after sodium roasting. Vanadium mainly enters the liquid phase as sodium vanadate (Na3VO4), while silicon coexists as sodium silicate (Na2SiO3). Silicon is a harmful impurity that must be removed. If it remains in the leachate, it will form silica gel or silicate co-precipitates during subsequent ammonium salt precipitation, which will not only severely reduce the purity of the product but also interfere with the crystallization behavior of vanadium.

[0010] As a preferred technical solution of the present invention, the desilication agent in step (1) includes any one or a combination of at least two of aluminum salt desilication agent, calcium salt desilication agent or magnesium salt desilication agent, wherein typical but non-limiting combinations include: a combination of aluminum salt desilication agent and calcium salt desilication agent, a combination of aluminum salt desilication agent and magnesium salt desilication agent, a combination of calcium salt desilication agent and magnesium salt desilication agent, preferably an aluminum salt desilication agent.

[0011] Preferably, the aluminum salt desilication agent comprises any one or a combination of at least two of aluminum sulfate, sodium aluminate, or aluminum chloride, wherein typical but non-limiting combinations include: a combination of aluminum sulfate and sodium aluminate, a combination of aluminum sulfate and aluminum chloride, and a combination of sodium aluminate and aluminum chloride.

[0012] In this invention, the core reaction mechanism of desilication is the addition of a desilication agent (such as NaAlO2 or Al2(SO4)3) to the alkaline leachate, utilizing Al... 3+ With SiO3 2- The strong affinity between them generates aluminosilicate precipitates with extremely low solubility (such as hydrated sodium aluminosilicate), thereby removing silicon from the liquid phase. In this process, desilication is only targeted at removing harmful impurities (such as silicon), while other beneficial impurity elements (such as chromium, calcium, potassium, etc.) are intentionally retained. These elements will act as "natural dopants" in subsequent steps to achieve synergistic doping modification of multiple elements.

[0013] As a preferred embodiment of the present invention, the vanadium concentration in the desilication leaching solution in step (1) is 32-46 g / L, for example, it can be 32 g / L, 34 g / L, 36 g / L, 38 g / L, 40 g / L, 42 g / L, 43 g / L, 44 g / L or 46 g / L; the chromium concentration is 1.3-2.7 g / L, for example, it can be 1.3 g / L, 1.5 g / L, 1.6 g / L, 1.7 g / L, 2.0 g / L, 2.2 g / L, 2.5 g / L, 2.6 g / L or 2.7 g / L; and the calcium concentration is 0.01-1 g / L, for example, it can be 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.3 g / L. / L, 0.4g / L, 0.5g / L, 0.6g / L, 0.7g / L, 0.8g / L, 0.9g / L or 1g / L, the mass concentration of potassium is 0.1-0.3g / L, for example it can be 0.1g / L, 0.15g / L, 0.2g / L, 0.25g / L or 0.3g / L, the mass concentration of other elements is <0.005g / L, for example it can be 0.0045g / L, 0.004g / L, 0.0035g / L, 0.003g / L, 0.0025g / L, 0.002g / L, 0.0015g / L or 0.001g / L, but is not limited to the listed values, other unlisted values ​​within the above range are also applicable.

[0014] As a preferred technical solution of the present invention, the molar ratio of the ammonium salt in step (2) to the vanadium in the desilication leaching solution is (1-2):1, for example, it can be 1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable, preferably (1.1-1.3):1.

[0015] In this invention, when the molar ratio of ammonium salt to vanadium in the desilication leaching solution is too low, and there is insufficient ammonium ion, most of the vanadium remains in the solution. Ammonium salt acts as a precipitant and intercalating agent; when insufficient, the lack of ammonium ion prevents effective vanadium precipitation, leading to a decrease in vanadium conversion and utilization. Conversely, when the molar ratio of ammonium salt to vanadium in the desilication leaching solution is too high, the ammonium salt hydrolyzes into a weakly acidic solution. Excessive ammonium salt lowers the solution pH, potentially causing partial dissolution of the already formed ammonium vanadate precipitate. Excessive ammonium salt also leads to the formation of anions (such as Cl-). - SO4 2- NO3 - The ammonium salt will be adsorbed or encapsulated in the precipitate and remain in the product after calcination, affecting the electrochemical performance of the material. Secondly, the excessive amount of ammonium salt fails to participate in the reaction effectively, resulting in a direct waste of ammonium salt reagent and increasing the cost of raw materials.

[0016] Preferably, the ammonium salt in step (2) includes any one or a combination of at least two of ammonium sulfate, ammonium chloride, or ammonium nitrate, wherein typical but non-limiting combinations include: a combination of ammonium sulfate and ammonium chloride, a combination of ammonium sulfate and ammonium nitrate, and a combination of ammonium chloride and ammonium nitrate.

[0017] In this invention, ammonium salts (such as NH4Cl, NH4NO3, (NH4)2SO4, etc.) are added to the desilication leaching solution, and a precipitation reaction occurs under suitable conditions to generate the precursor—ammonium vanadate precipitate.

[0018] Preferably, the precipitation reaction in step (2) is carried out under stirring.

[0019] Preferably, the stirring speed is 200-500 r / min, and the stirring time is 2-5 h.

[0020] As a preferred technical solution of the present invention, the silicon content in the desilication leachate in step (1) is ≤20mg / L, for example, it can be 20mg / L, 19mg / L, 18mg / L, 17mg / L, 16mg / L, 15mg / L, 14mg / L, 13mg / L or 20mg / L, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0021] Preferably, the pH value of the desilication leachate in step (1) is 8-11, for example, it can be 8, 8.2, 8.4, 8.6, 8.8, 8.9, 9.0, 9.2, 9.4, 9.6, 9.8, 10, 10.2, 10.4, 10.6, 10.8 or 11, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable, preferably 9-10.

[0022] In this invention, the desilication rate decreases when the pH value of the desilication leachate is too low or too high.

[0023] As a preferred technical solution of the present invention, the calcination temperature in step (3) is 250-350°C, for example, it can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0024] In this invention, if the calcination temperature is too low, excessive retention of interlayer ammonium ions affects ion diffusion and reduces electrochemical capacity; if the calcination temperature is too high, vanadium oxide may transform from a layered structure to other thermodynamically more stable phases at high temperatures (such as from V2O5 to V3O7 and V6O). 13This process disrupts the electrochemical activity of the target material. The particles also undergo severe sintering and growth, forming micron-sized bulk particles, which is detrimental to subsequent electrode fabrication and ion diffusion. Therefore, this invention controls the calcination temperature to 250-350℃, retaining the ammonium ions in the precursor as intercalation ions, resulting in a suitable interlayer spacing.

[0025] Preferably, the calcination time in step (3) is 1-3 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] Preferably, the heating rate of the calcination treatment in step (3) is 1-5°C / min, for example, it can be 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0027] Preferably, the calcination treatment in step (3) is carried out under an inert atmosphere.

[0028] Preferably, the inert atmosphere includes nitrogen and / or argon.

[0029] As a preferred technical solution of the present invention, the preparation method specifically includes the following steps: (1) Add a desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out a desilication reaction to obtain a desilication leachate; wherein, the desilication agent includes any one or a combination of at least two of aluminum salt desilication agent, calcium salt desilication agent or magnesium salt desilication agent, the aluminum salt desilication agent includes any one or a combination of at least two of aluminum sulfate, sodium aluminate or aluminum chloride, the mass concentration of vanadium in the desilication leachate is 32-46 g / L, the mass concentration of chromium is 1.3-2.7 g / L, the mass concentration of calcium is 0.01-1 g / L, the mass concentration of potassium is 0.1-0.3 g / L, the mass concentration of other elements is <0.005 g / L, the silicon content in the desilication leachate is ≤20 mg / L, and the pH value of the desilication leachate is 8-11; (2) Add ammonium salt to the desilication leaching solution in step (1) to carry out a precipitation reaction, and obtain the precursor by solid-liquid separation; wherein, the molar ratio of the ammonium salt to vanadium in the desilication leaching solution is (1-2):1, the ammonium salt includes any one or a combination of at least two of ammonium sulfate, ammonium chloride or ammonium nitrate, the precipitation reaction is carried out under stirring, the stirring speed is 200-500 r / min, and the stirring time is 2-5 h; (3) The precursor described in step (2) is subjected to drying and calcination treatment in sequence to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination treatment temperature is 250-350°C, the calcination treatment time is 1-3h, the calcination treatment heating rate is 1-5°C / min, and the calcination treatment is carried out under an inert atmosphere, the inert atmosphere including nitrogen and / or argon.

[0030] In a second aspect, the present invention provides a multi-element doped ammonium intercalated vanadium oxide material prepared by the preparation method described in the first aspect, wherein the doped elements in the multi-element doped ammonium intercalated vanadium oxide material include chromium, calcium and potassium; The mass percentage of chromium, calcium, and potassium doped in the multi-doped ammonium intercalated vanadium oxide material is independently 0.2%-2%, for example, 0.2%, 0.5%, 1.0%, 1.5%, or 2%, and the mass percentage of nitrogen is 1%-3%, for example, 1%, 1.5%, 2%, 2.5%, or 3%, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0031] As a preferred technical solution of the present invention, the multi-doped ammonium intercalated vanadium oxide material is a layered material, and the interlayer spacing of the layered material is 1.2-1.3 nm, for example, it can be 1.2 nm, 1.22 nm, 1.24 nm, 1.26 nm, 1.28 nm or 1.3 nm, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0032] Preferably, the average particle size of the multi-doped ammonium intercalated vanadium oxide material is 1-5 μm, for example, it can be 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0033] Thirdly, the present invention provides an application of the multi-doped ammonium intercalated vanadium oxide material described in the second aspect, wherein the multi-doped ammonium intercalated vanadium oxide material is used as a positive electrode active material.

[0034] Preferably, the positive electrode active material is used in a zinc-ion battery, and more preferably in an aqueous zinc-ion battery.

[0035] In this invention, the positive electrode of the zinc-ion battery is composed of a positive electrode active material, a conductive agent, a binder, and a current collector. The conductive agent and binder, and their amounts, are not specifically limited; those skilled in the art can choose known conductive agents and binders, such as conductive carbon black as the conductive agent and polyvinylidene fluoride as the binder. Those skilled in the art can choose known current collectors, such as titanium foil, carbon cloth, or carbon paper, without specific limitations.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The preparation method of the present invention uses sodium roasting alkaline leaching solution of vanadium slag as preparation raw material, thereby reducing the requirements for vanadium purity in the preparation process and reducing the cost of the preparation process; the precipitation method is adopted, by adding ammonium salt to the desilication leaching solution to generate a precipitate to obtain a precursor, and then calcining the dried precursor to obtain the multi-doped-ammonium intercalated vanadium oxide material. (2) The multi-component doped ammonium intercalated material prepared by this invention contains ammonium ion intercalation and also has the characteristic of large interlayer spacing, with an interlayer spacing of 1.2-1.3 nm. When used as a cathode material for aqueous zinc-ion batteries, it has a density of 0.1 A·g -1 The specific capacity is higher than 389 mAh·g under current density conditions. -1 Under preferred conditions, the capacity is higher than 432 mAh•g-1, and after 600 cycles, it can retain more than 87.5% of the initial capacity, with a retention rate of more than 91.8% under preferred conditions. Attached Figure Description

[0037] Figure 1 This is an X-ray powder diffraction pattern of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 2 This is the Raman spectrum of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 3 This is a scanning electron microscope image of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 4 This is a scanning electron microscope image of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 2 of this invention; Figure 5 This is a scanning electron microscope image of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 3 of this invention; Figure 6 This is a transmission electron microscope (TEM) image of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 7 This is the XPS curve of O1s of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 8 This is the XPS curve of V2p of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of this invention; Figure 9 This is a charge-discharge curve of the electrode of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of the present invention, tested in an aqueous zinc ion system. Figure 10 This is a cycle diagram of the electrode of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 of the present invention, tested in an aqueous zinc ion system. Detailed Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0039] Example 1 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Add aluminum sulfate desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out desilication reaction to obtain desilication leachate; wherein, the mass concentration of vanadium in the desilication leachate is 43 g / L, the mass concentration of chromium is 1.3 g / L, the mass concentration of calcium is 0.05 g / L, the mass concentration of potassium is 0.1 g / L, and the mass concentrations of other elements such as iron, manganese, titanium, and sodium are <0.005 g / L, the silicon content in the desilication leachate is ≤10 mg / L, and the pH value of the desilication leachate is 8.9; (2) Add ammonium sulfate to the desilication leaching solution in step (1) to carry out a precipitation reaction, wherein the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 1.2:1, the precipitation reaction is carried out under stirring, the stirring speed is 400 r / min, the stirring time is 3 h until the precipitation is completed, and the precipitate is filtered to obtain the precursor. (3) The precursor described in step (2) is dried at 70°C and calcined in a nitrogen atmosphere to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination temperature is 300°C, the calcination time is 2h, and the calcination heating rate is 5°C / min.

[0040] The X-ray powder diffraction pattern of the multi-doped ammonium intercalated vanadium oxide material prepared by the preparation method provided in this embodiment is as follows: Figure 1 As shown, by Figure 1It can be seen that the product is a vanadium oxide with a large interlayer spacing, which can be calculated to be 1.23 nm using Bragg's law; its Raman spectrum is as follows. Figure 2 As shown, by Figure 2 It can be seen that the V=O bonds in the product are similar to those in vanadium pentoxide; its scanning electron microscope image is shown below. Figure 3 As shown, the particle size of vanadium oxide is 1-5 μm; its transmission electron microscopy (TEM) image is shown below. Figure 6 As shown, the prepared product contains intercalated vanadium oxide with a lattice spacing of 1.23 nm, consistent with XRD. Figure 7 , Figure 8 The XPS curves for O1s and V2p of vanadium oxides with multi-component doping and ammonium intercalation are shown respectively. It can be seen that vanadium in the product mainly exists in pentavalent and tetravalent forms, and there are defect O in the product.

[0041] Example 2 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Add aluminum sulfate desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out desilication reaction to obtain desilication leachate; wherein, the mass concentration of vanadium in the desilication leachate is 43 g / L, the mass concentration of chromium is 2.6 g / L, the mass concentration of calcium is 0.1 g / L, the mass concentration of potassium is 0.2 g / L, and the mass concentrations of other elements such as iron, manganese, titanium, and sodium are <0.005 g / L, the silicon content in the desilication leachate is ≤20 mg / L, and the pH value of the desilication leachate is 9; (2) Add ammonium sulfate to the desilication leaching solution in step (1) to carry out a precipitation reaction, wherein the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 1.2:1, the precipitation reaction is carried out under stirring, the stirring speed is 300 r / min, the stirring time is 3 h until the precipitation is completed, and the precipitate is filtered to obtain the precursor. (3) The precursor described in step (2) is dried at 70°C and calcined in a nitrogen atmosphere to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination temperature is 300°C, the calcination time is 2h, and the calcination heating rate is 5°C / min.

[0042] The scanning electron microscope (SEM) image of the multi-doped ammonium-intercalated vanadium oxide material prepared by the preparation method provided in this embodiment is shown below. Figure 4 As shown, the particle size of vanadium oxide is 2-4 μm.

[0043] Example 3 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Sodium aluminate desilication agent is added to the alkaline leachate of sodium-roasted vanadium slag to carry out desilication reaction to obtain desilication leachate; wherein, the mass concentration of vanadium in the desilication leachate is 40 g / L, the mass concentration of chromium is 1.6 g / L, the mass concentration of calcium is 0.2 g / L, the mass concentration of potassium is 0.3 g / L, and the mass concentrations of other elements such as iron, manganese, titanium, and sodium are <0.005 g / L, the silicon content in the desilication leachate is ≤20 mg / L, and the pH value of the desilication leachate is 9; (2) Add ammonium sulfate to the desilication leaching solution in step (1) to carry out a precipitation reaction, wherein the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 1.3:1, the precipitation reaction is carried out under stirring, the stirring speed is 500 r / min, the stirring time is 3 h until the precipitation is completed, and the precipitate is filtered to obtain the precursor. (3) The precursor described in step (2) is dried at 70°C and calcined in a nitrogen atmosphere to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination temperature is 300°C, the calcination time is 2h, and the calcination heating rate is 5°C / min.

[0044] The scanning electron microscope (SEM) image of the multi-doped ammonium-intercalated vanadium oxide material prepared by the preparation method provided in this embodiment is shown below. Figure 5 As shown, the particle size of vanadium oxide is 1-3 μm.

[0045] Example 4 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Add aluminum sulfate to the alkaline leachate of sodium-roasted vanadium slag to carry out desilication reaction to obtain desilication leachate; wherein, the mass concentration of vanadium in the desilication leachate is 40 g / L, the mass concentration of chromium is 1.6 g / L, the mass concentration of calcium is 0.2 g / L, the mass concentration of potassium is 0.3 g / L, and the mass concentrations of other elements such as iron, manganese, titanium, and sodium are <0.005 g / L, the silicon content in the desilication leachate is ≤10 mg / L, and the pH value of the desilication leachate is 9; (2) Add ammonium salt to the desilication leaching solution in step (1) to carry out a precipitation reaction, wherein the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 1:1, the precipitation reaction is carried out under stirring, the stirring speed is 200 r / min, the stirring time is 5 h until the precipitation is completed, and the precipitate is filtered to obtain the precursor. (3) The precursor described in step (2) is dried at 80°C and calcined in an argon atmosphere to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination temperature is 250°C, the calcination time is 3h, and the calcination heating rate is 1°C / min.

[0046] Example 5 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material, the method comprising the following steps: (1) Sodium aluminate is added to the alkaline leachate of sodium-roasted vanadium slag to carry out desilication reaction to obtain desilication leachate; wherein, the mass concentration of vanadium in the desilication leachate is 40 g / L, the mass concentration of chromium is 1.6 g / L, the mass concentration of calcium is 0.2 g / L, the mass concentration of potassium is 0.3 g / L, and the mass concentrations of other elements such as iron, manganese, titanium, and sodium are <0.005 g / L, the silicon content in the desilication leachate is ≤20 mg / L, and the pH value of the desilication leachate is 9; (2) Add ammonium salt to the desilication leaching solution in step (1) to carry out a precipitation reaction, wherein the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 2:1, the precipitation reaction is carried out under stirring, the stirring speed is 500 r / min, the stirring time is 2 h until the precipitation is completed, and the precipitate is filtered to obtain the precursor. (3) The precursor described in step (2) is dried at 90°C and calcined in a nitrogen atmosphere to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination temperature is 350°C, the calcination time is 1h, and the calcination heating rate is 3°C / min.

[0047] Example 6 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Example 1 is that, except for the pH value of the desilication leaching solution in step (1) being 7, all other aspects are the same as in Example 1.

[0048] Example 7 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Embodiment 1 is that, except for the pH value of the desilication leaching solution in step (1) being 12, all other aspects are the same as in Embodiment 1.

[0049] Example 8 This embodiment provides a method for preparing a multi-element doped ammonium intercalated vanadium oxide material. The only difference from Embodiment 1 is that the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 0.5:1. All other aspects are the same as in Embodiment 1.

[0050] Example 9 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Embodiment 1 is that, except that the molar ratio of the ammonium salt to the vanadium element in the desilication leaching solution is 3:1, everything else is the same as in Embodiment 1.

[0051] Example 10 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Embodiment 1 is that, except that the calcination temperature in step (3) is 200°C, everything else is the same as in Embodiment 1.

[0052] Example 11 This embodiment provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Embodiment 1 is that, except that the calcination temperature in step (3) is 400°C, everything else is the same as in Embodiment 1.

[0053] Comparative Example 1 This comparative example provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference between this example and Example 1 is that, except for step (1) which does not involve a desiliconization reaction, the rest is the same as in Example 1.

[0054] Comparative Example 2 This comparative example provides a method for preparing vanadium oxide material with ammonium intercalation and no other element doping. The only difference from Example 1 is that, except that step (2) uses a pure sodium metavanadate solution instead of a desilication leaching solution, the rest is the same as Example 1.

[0055] Comparative Example 3 This comparative example provides a method for preparing a multi-doped ammonium intercalated vanadium oxide material. The only difference from Example 1 is that, except for step (3) which involves calcination in air, the rest is the same as in Example 1.

[0056] Application Example 1 In this application example, the multi-doped ammonium intercalated vanadium oxide material obtained in Example 1 is used to manufacture an electrode. The preparation method of the electrode includes: mixing active material, carbon black (Super P) and polyvinylidene fluoride (PVDF) binder in a weight ratio of 7:2:1, dissolving in an appropriate amount of N-methylpyrrolidone (NMP), forming a homogeneous slurry, coating it on a titanium foil, and drying it in a vacuum oven at 70°C.

[0057] Figure 9 The electrode prepared in this application example is used in an aqueous zinc-ion battery system at 0.1 A·g -1The charge-discharge curves under the test current density conditions are shown in the figure. It can be seen from the figure that the electrode at 0.1 A·g -1 The specific capacity can reach 454.4 mAh·g. -1 . Figure 10 The cycling stability of the multi-doped ammonium intercalated vanadium oxide material prepared in Example 1 as an electrode in an aqueous zinc-ion battery system is demonstrated at 1 A·g. -1 The initial capacity is maintained at 93.8% after 600 cycles.

[0058] Application Example 2-11 The difference from Application Example 1 is that, except that this Application Example uses the multi-component doped ammonium intercalated vanadium oxide material prepared in Examples 2-11, everything else is the same as Application Example 1.

[0059] Application Comparative Examples 1-3 The difference from Application Example 1 is that, except that this Application Example uses the multi-component doped ammonium intercalated vanadium oxide material prepared in Comparative Examples 1-3, everything else is the same as Application Example 1.

[0060] Test method: The electrode is in an aqueous zinc-ion battery system and at 0.1 A·g -1 Charge-discharge curves, specific capacity, and current density at 1 A·g were measured under current density conditions. -1 The capacity retention rate after 600 cycles is shown in Table 1.

[0061] Table 1 The test results show that: (1) As can be seen from Application Examples 1 to 5, the present invention uses the sodium-calcined alkaline leaching solution of vanadium slag as the raw material, thereby reducing the requirements for vanadium purity in the preparation process and reducing the cost of the preparation process; by using the precipitation method, ammonium salt is added to the desilication leaching solution to generate a precipitate to obtain the precursor, and then the dried precursor is calcined at low temperature to obtain the multi-element doped-ammonium intercalated vanadium oxide material. The multi-element doped-ammonium intercalated vanadium oxide material has the characteristic of large interlayer spacing. When the obtained cathode material is used in an aqueous zinc-ion battery, it achieves a purity of 0.1 A·g -1 The specific capacity can reach up to 463 mAh·g under current density conditions. -1 After 600 cycles, it can retain up to 93.8% of its initial capacity.

[0062] (2) As can be seen from Application Examples 1, 6 and 7, when the pH value of the desilication leachate is too high or too low, the desilication rate decreases, silicon impurities increase, and the electrochemical performance of the battery decreases.

[0063] (3) As can be seen from Application Examples 1 and 8 and 9, when the molar ratio of ammonium salt to vanadium in the desilication leaching solution is too low, and there is insufficient ammonium ions, most of the vanadium remains in the solution. Ammonium salt acts as a precipitant and intercalating agent. When there is insufficient ammonium salt, the mass of the precipitate precursor generated is small, and the vanadium utilization rate is low. When the molar ratio of ammonium salt to vanadium in the desilication leaching solution is too high, the ammonium salt hydrolyzes to a weakly acidic state. Excessive ammonium salt causes the pH of the solution to drop, which may lead to partial dissolution of the already formed ammonium vanadate precipitate. Excessive ammonium salt is accompanied by anions (such as Cl-). - SO4 2- NO3 - It will be adsorbed or encapsulated in the precipitate, and remain in the product after calcination, affecting the electrochemical performance of the material.

[0064] (4) As can be seen from Application Examples 1, 10, and 11, when the calcination temperature is too low, too many ammonium ions are retained in the interlayer, affecting ion diffusion and reducing the electrochemical capacity; when the calcination temperature is too high, vanadium oxide may transform from a layered structure to other thermodynamically more stable phases at high temperatures (such as transforming from V2O5 phase to V3O7 and V6O). 13 This process disrupts the electrochemical activity of the target material. The particles also undergo severe sintering and growth, forming micron-sized bulk particles, which is detrimental to subsequent electrode fabrication and ion diffusion. Therefore, this invention controls the calcination temperature to 250-350℃, retaining the ammonium ions in the precursor as intercalation ions, thus achieving a suitable interlayer spacing.

[0065] (5) As can be seen from Example 1 and Comparative Example 1, when the present invention does not perform desiliconization treatment, impurities such as silicon in the leachate may co-precipitate during vanadium precipitation, resulting in a significant excess of silicon content in the final vanadium oxide material, which seriously affects the electrochemical performance of the material.

[0066] (6) As can be seen from Example 1 and Comparative Example 2, there is a significant difference between multi-metal ion doping and no doping. Multi-metal ion doping has the effect of electronic structure regulation, which can effectively reduce the band gap and significantly improve the conductivity, thus obtaining higher capacity performance and rate performance.

[0067] (7) As can be seen from Example 1 and Comparative Example 3, vanadium pentoxide calcined in air has too low a capacity and does not have an advantage in electrochemical energy storage. Low-temperature calcination in an inert atmosphere forms vanadium pentoxide with redox activity. 5+ / V 4+ The mixed valence system allows for suitable ammonium intercalation and O vacancies, all of which are beneficial for electrochemical energy storage. Vanadium pentoxide obtained by calcination in air primarily exists as V... 5+ Its main characteristics are small interlayer spacing and few oxygen vacancies, large band gap, low electronic conductivity and slow ion migration rate, resulting in poor electrochemical performance.

[0068] In summary, this invention uses the sodium-calcined alkaline leaching solution of vanadium slag as the raw material, thereby reducing the requirements for vanadium purity and the cost of the preparation process. The precipitation method is adopted, in which ammonium salt is added to the desilication leaching solution to generate a precipitate to obtain the precursor. Then, the dried precursor is calcined under an inert atmosphere to obtain the multi-doped-ammonium intercalated vanadium oxide material.

[0069] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a multi-component doped-ammonium intercalated vanadium oxide material, characterized in that, The preparation method includes the following steps: (1) Add a desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out a desilication reaction, and obtain a desilication leachate; (2) Add ammonium salt to the desilication leachate obtained in step (1) to carry out a precipitation reaction, and obtain the precursor by solid-liquid separation; (3) The precursor described in step (2) is subjected to drying and calcination treatment in sequence to prepare the multi-doped ammonium intercalated vanadium oxide material.

2. The preparation method according to claim 1, characterized in that, The desilication agent in step (1) includes any one or a combination of at least two of aluminum salt desilication agents, calcium salt desilication agents or magnesium salt desilication agents, preferably aluminum salt desilication agents; Preferably, the aluminum salt desilication agent includes any one or a combination of at least two of aluminum sulfate, sodium aluminate, or aluminum chloride.

3. The preparation method according to claim 1 or 2, characterized in that, The mass concentration of vanadium in the desilication leaching solution in step (1) is 32-46 g / L, the mass concentration of chromium is 1.3-2.7 g / L, the mass concentration of calcium is 0.01-1 g / L, the mass concentration of potassium is 0.1-0.3 g / L, and the mass concentration of other elements is <0.005 g / L.

4. The preparation method according to any one of claims 1-3, characterized in that, In step (2), the molar ratio of the ammonium salt to the vanadium in the desilication leaching solution is (1-2):1, preferably (1.1-1.3):1; Preferably, the ammonium salt in step (2) includes any one or a combination of at least two of ammonium sulfate, ammonium chloride, or ammonium nitrate; Preferably, the precipitation reaction in step (2) is carried out under stirring. Preferably, the stirring speed is 200-500 r / min, and the stirring time is 2-5 h.

5. The preparation method according to any one of claims 1-4, characterized in that, The silicon content in the desilication leachate of step (1) is ≤20 mg / L; Preferably, the pH value of the desilication leachate in step (1) is 8-11, and more preferably 9-10.

6. The preparation method according to any one of claims 1-5, characterized in that, The calcination temperature in step (3) is 250-350°C; Preferably, the calcination treatment in step (3) takes 1-3 hours; Preferably, the heating rate of the calcination treatment in step (3) is 1-5°C / min; Preferably, the calcination treatment in step (3) is carried out under an inert atmosphere; Preferably, the inert atmosphere includes nitrogen and / or argon.

7. The preparation method according to any one of claims 1-6, characterized in that, The preparation method specifically includes the following steps: (1) Add a desilication agent to the alkaline leachate of sodium-roasted vanadium slag to carry out a desilication reaction to obtain a desilication leachate; wherein, the desilication agent includes any one or a combination of at least two of aluminum salt desilication agent, calcium salt desilication agent or magnesium salt desilication agent, the aluminum salt desilication agent includes any one or a combination of at least two of aluminum sulfate, sodium aluminate or aluminum chloride, the mass concentration of vanadium in the desilication leachate is 32-46 g / L, the mass concentration of chromium is 1.3-2.7 g / L, the mass concentration of calcium is 0.01-1 g / L, the mass concentration of potassium is 0.1-0.3 g / L, the mass concentration of other elements is <0.005 g / L, the silicon content in the desilication leachate is ≤20 mg / L, and the pH value of the desilication leachate is 8-11; (2) Add ammonium salt to the desilication leaching solution in step (1) to carry out a precipitation reaction, and obtain the precursor by solid-liquid separation; wherein, the molar ratio of the ammonium salt to vanadium in the desilication leaching solution is (1-2):1, the ammonium salt includes any one or a combination of at least two of ammonium sulfate, ammonium chloride or ammonium nitrate, the precipitation reaction is carried out under stirring, the stirring speed is 200-500 r / min, and the stirring time is 2-5 h; (3) The precursor described in step (2) is subjected to drying and calcination treatment in sequence to prepare the multi-doped ammonium intercalated vanadium oxide material; wherein the calcination treatment temperature is 250-350°C, the calcination treatment time is 1-3h, the calcination treatment heating rate is 1-5°C / min, and the calcination treatment is carried out under an inert atmosphere, the inert atmosphere including nitrogen and / or argon.

8. A multi-component doped ammonium intercalated vanadium oxide material prepared by the preparation method according to any one of claims 1-7, characterized in that, The elements doped in the multi-doped ammonium intercalated vanadium oxide material include chromium, calcium, and potassium; The mass percentages of chromium, calcium, and potassium in the multi-doped ammonium intercalated vanadium oxide material are each 0.2%-2%, and the mass percentage of nitrogen is 1%-3%.

9. The multi-doped ammonium intercalated vanadium oxide material according to claim 8, characterized in that, The multi-doped ammonium intercalated vanadium oxide material is a layered material with an interlayer spacing of 1.2-1.3 nm. Preferably, the average particle size of the multi-doped ammonium intercalated vanadium oxide material is 1-5 μm.

10. An application of a multi-doped ammonium intercalated vanadium oxide material according to claim 8 or 9, characterized in that, The multi-doped ammonium intercalated vanadium oxide material is used as the positive electrode active material; Preferably, the positive electrode active material is used in a zinc-ion battery, and more preferably in an aqueous zinc-ion battery.

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