A method for preparing a vanadium-based layered electrode material for zinc-ion batteries

Abstract

This invention discloses a method for preparing a vanadium-based metamorphic electrode material for zinc-ion batteries, comprising the following steps: providing a vanadium-based metamorphic oxide precursor; performing a first intercalation treatment on the vanadium-based metamorphic oxide precursor, introducing a metal ion source to allow metal ions to insert into the interlayer space of the vanadium-based metamorphic oxide precursor, accompanied by the formation of a soluble ineffective transition phase; performing a second intercalation treatment on the product after the first intercalation treatment, introducing organic amine molecules to dissolve the soluble ineffective transition phase, and co-intercalating the organic amine molecules and the metal ions into the interlayer space of the vanadium-based metamorphic oxide precursor to obtain the vanadium-based metamorphic electrode material. This invention utilizes the synergistic intercalation of metal ions and organic amine molecules and the growth-dissolution activation mechanism of the transition phase to achieve synergistic optimization of interlayer spacing expansion, structural stability improvement, and unobstructed ion transport channels, thereby significantly improving specific capacity and cycle stability.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage materials, specifically to a method for preparing a vanadium-based substrate electrode material for zinc-ion batteries. Background Technology

[0002] Currently, aqueous zinc-ion batteries have shown broad application prospects in the field of flexible wearable energy storage devices due to their advantages such as high safety, low cost, and environmental friendliness. Vanadium-based layered oxides, as candidates for zinc-ion battery cathode materials, have characteristics such as high theoretical specific capacity and suitable redox potential. However, existing vanadium-based layered oxide cathode materials generally suffer from small interlayer spacing, which hinders the diffusion kinetics of zinc ions during insertion / extraction. At the same time, under repeated charge-discharge cycles, the strong electrostatic interaction of zinc ions easily causes the collapse and destruction of the layered structure, resulting in poor cycle stability. In addition, conventional single-ion intercalation modification strategies often fail to effectively open ion transport channels while improving structural stability, and may even generate ineffective phases that hinder ion migration, resulting in low utilization of active sites and difficulty in achieving breakthroughs in specific capacity. Therefore, there is an urgent need for a layered electrode material design scheme that can synergistically expand the interlayer spacing, stabilize the crystal structure, and open up ion transport channels. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a vanadium-based substrate electrode material for zinc-ion batteries. This invention utilizes the synergistic intercalation of metal ions and organic amine molecules, along with the growth-dissolution activation mechanism of the transition phase, to achieve synergistic optimization of interlayer spacing, improved structural stability, and unobstructed ion transport channels, thereby significantly improving specific capacity and cycle stability.

[0004] The technical solution of the present invention: a method for preparing a vanadium-based substrate electrode material for zinc-ion batteries, comprising:

[0005] Provides vanadium-based base oxide precursors;

[0006] The vanadium-based oxide precursor is subjected to a first intercalation treatment, in which a metal ion source is introduced to allow metal ions to be inserted into the interlayer of the vanadium-based oxide precursor, accompanied by the formation of a soluble ineffective transition phase.

[0007] A second intercalation treatment is performed on the product after the first intercalation treatment to introduce organic amine molecules, dissolve the soluble ineffective transition phase, and co-intercalate the organic amine molecules and the metal ions into the interlayer of the vanadium-based oxide precursor to obtain a vanadium-based electrode material.

[0008] In the above-mentioned method for preparing vanadium-based substrate electrode materials, the soluble ineffective transition phase is a metal carbonate.

[0009] In the aforementioned method for preparing vanadium-based substrate electrode materials, the organic amine molecule is a polyamine organic molecule or a nitrogen-containing chelating intercalating agent.

[0010] In the aforementioned method for preparing vanadium-based substrate electrode materials, the metal ion is calcium ion, the organic amine molecule is diethylenetriamine, and the metal carbonate is calcium carbonate.

[0011] The aforementioned method for preparing vanadium-based morphological electrode materials further includes immersing carbon paper as a substrate into a reaction system, thereby allowing the vanadium-based morphological electrode material to grow in situ on the surface of the carbon paper to form a self-supporting electrode structure.

[0012] In the aforementioned method for preparing vanadium-based crystalline electrode materials, the temperature of the first intercalation treatment is 110°C to 130°C, and the time is 1 hour to 3 hours.

[0013] The second intercalation treatment is carried out at a temperature of 170°C to 190°C for a time of 0.5 hours to 2 hours, and at a pH of 2 to 4.

[0014] The aforementioned method for preparing vanadium-based substrate electrode materials includes a metal ion source comprising a soluble calcium salt and a calcium complex containing a carbon source; the soluble calcium salt includes calcium metavanadate, and the calcium complex containing a carbon source includes calcium gluconate.

[0015] A vanadium-based morphological electrode material includes a vanadium-based morphological oxide matrix, wherein the interlayers of the vanadium-based morphological oxide matrix contain intercalated metal ions and organic amine molecules, and the vanadium-based morphological electrode material does not contain a soluble ineffective transition phase.

[0016] The aforementioned vanadium-based morphological electrode material has an interlayer spacing of 1.0 nm to 1.2 nm and contains oxygen vacancies.

[0017] A zinc-ion battery includes a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode comprises the aforementioned vanadium-based layered electrode material.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention utilizes the synergistic intercalation of metal ions and organic amine molecules. The pillar effect of metal ions effectively expands and stabilizes the interlayer spacing of layered oxides, suppressing structural collapse during zinc ion insertion / extraction. The co-intercalation of organic amine molecules further optimizes the interlayer microenvironment, and its nitrogen-containing groups chelate zinc ions, reducing the intercalation energy barrier of zinc ions. The synergistic effect of both significantly improves the reaction kinetics and cycle stability of the material.

[0020] 2. This invention utilizes a unique "transition phase growth-dissolution activation" mechanism. In the first intercalation process, the soluble ineffective transition phase (such as metal carbonate) generated during the first intercalation process acts as a condensation nucleus, promoting the dense growth and uniform coating of the active material on the substrate surface, thus fully utilizing the conductive network of the substrate. In the second intercalation process, the ineffective transition phase is dissolved and removed, and the originally occupied or blocked ion transport channels are completely activated, allowing the electrolyte to fully wet the internal active sites, thereby eliminating ineffective mass and significantly improving the utilization rate and specific capacity of the active material.

[0021] 3. This invention constructs an integrated self-supporting structure of active material and three-dimensional conductive network by in-situ growing active material on carbon paper substrate. The porous skeleton of carbon paper not only provides sufficient load space and mechanical support for active material, giving the electrode excellent flexibility and mechanical strength, but its three-dimensional conductive network also ensures rapid electron transport and full penetration of electrolyte, effectively reducing interface impedance and meeting the requirements of flexible wearable devices for high safety and mechanical deformation tolerance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the formation of the layered electrode material according to an embodiment of the present invention;

[0023] Figure 2 These are characterization images of the electrode surface morphology and microstructure according to embodiments of the present invention; wherein, (b) is the surface morphology of Ca-EDA@VO / CP; (c) is the flower-like crystal cluster morphology of Ca-EDA@VO; (d) is the internal morphology of Ca-EDA@VO / CP; (e) is the surface morphology of VO / CP; (f) is the TEM image of the crystals on VO / CP; (g) is the TEM image of the crystals on Ca-EDA@VO / CP; (h) is the SADE image of the crystals on Ca-EDA@VO / CP; and (i) is the EDS spectrum of the crystals on Ca-EDA@VO / CP.

[0024] Figure 3 These are phase and spectral characterization diagrams of the electrode materials according to embodiments of the present invention; wherein (a) is an XRD pattern; (b) is an FTIR pattern; (c) is a Raman pattern; (d) is an EPR pattern; (e) is an XPS total spectrum; (f) is an XPS pattern of V 2p; (g) is an ICP-MS pattern of Ca and VO; (h) is a TGA pattern; and (i) is an infrared thermogravimetric correlation diagram of the crystal clusters on Ca-EDA@VO / CP.

[0025] Figure 4 These are physical property characterization diagrams of the self-supporting electrode according to an embodiment of the present invention; (a) is the vertical resistivity; (b) is the planar resistivity; (c) is the water contact angle; (d) is the adsorption-desorption curve; (e) is the pore size distribution; (f) is the stress-strain intensity; and (g) is a physical image of different electrode sheets.

[0026] Figure 5 These are electrochemical performance characterization diagrams of the coin cell according to embodiments of the present invention; (a) is the CV curve tested at 0.5 mV·s⁻¹; (b) is the GCD curve tested at 0.5 A·g⁻¹; (c) is the rate performance; (d) is the capacitance contribution at different scan rates; (e) is the Zn content under different discharge states. 2+ Diffusion coefficient; (f) EIS curve; (g) Long-cycle test at 0.5 A·g⁻¹; (h) Application diagram of button cell;

[0027] Figure 6 These are characterization diagrams of the electrode zinc storage mechanism in embodiments of the present invention; (a) is a charge-discharge schematic diagram; (b) is the XPS of the crystal on Ca-EDA@VO / CP at different voltages under C 1s; (c) is the XPS of the crystal on Ca-EDA@VO / CP at different voltages under N 1s; (d) is the XPS of the crystal on Ca-EDA@VO / CP at different voltages under O 1s; (e) is the XPS of the crystal on Ca-EDA@VO / CP at different voltages under V 2p; (f) is the Raman diagram of the crystal on Ca-EDA@VO / CP at different voltages; (g) is the EDS diagram of the crystal on Ca-EDA@VO / CP after charging; (h) is the EDS diagram of Ca-EDA@VO / CP after discharging.

[0028] Figure 7 The following are diagrams illustrating the structure and performance testing of the flexible pouch battery according to an embodiment of the present invention: (a) Schematic diagram of the assembly of Ca-EDA@VO / CP SSGE-ZIBs; (b) GCD curves of Ca-EDA@VO / CP SSGE-ZIBs at different current densities; (c) CV curves of Ca-EDA@VO / CP SSGE-ZIBs at different scan speeds; (d) Pseudocapacitance contribution ratio of Ca-EDA@VO / CP SSGE-ZIBs at different scan speeds; (e) Impedance change of Ca-EDA@VO / CP SSGE-ZIBs after different number of cycles; (f) LED wristband illuminated by three Ca-EDA@VO / CP SSGE-ZIBs; (g) Voltage performance of Ca-EDA@VO / CP SSGE-ZIBs under different bending angles and damage conditions. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides a method for preparing a vanadium-based substrate electrode material for zinc-ion batteries. Through the "transition phase growth-dissolution activation" mechanism, the synergistic optimization of dense growth of active materials and unobstructed ion transport channels is achieved.

[0032] Step S100: Provide a vanadium-based layered oxide precursor. In this embodiment, the vanadium-based layered oxide precursor is layered ammonium vanadium oxide (NH4V4O). 10 It is formed by hydrothermal in-situ crystallization of calcium metavanadate. It has open layered channels, high crystallinity and good intercalation compatibility. The original interlayer spacing is about 0.98 nm. It can accept the co-intercalation of metal ions and organic amine molecules. It is the core framework for constructing high-capacity, long-cycle zinc-ion battery cathodes.

[0033] Step S200: Perform a first intercalation treatment on the vanadium-based oxide precursor by introducing a metal ion source to insert metal ions into the interlayer of the vanadium-based oxide precursor, accompanied by the formation of a soluble ineffective transition phase.

[0034] Specifically, in the first intercalation process, metal ions enter the interlayer of the precursor to exert a pillar effect, while a soluble ineffective transition phase is generated in the reaction system. This ineffective transition phase acts as a condensation nucleus, promoting the dense growth of the active material, which in turn allows layered oxides to grow rapidly around it, achieving a high-density loading of the active material.

[0035] Step S300: Perform a second intercalation treatment on the product after the first intercalation treatment, introduce organic amine molecules, dissolve the soluble ineffective transition phase, and co-intercalate the organic amine molecules and the metal ions into the interlayer of the vanadium-based oxide precursor to obtain a vanadium-based electrode material.

[0036] Specifically, in the second intercalation process, organic amine molecules and metal ions co-intercalate into the interlayer space, while the soluble ineffective transition phase generated in the first step is dissolved and removed. The space previously occupied by the ineffective transition phase is transformed into unobstructed ion transport channels. The co-intercalation of organic amine molecules and metal ions further expands the interlayer spacing and enhances structural stability. This embodiment is illustrative only and not limiting.

[0037] Example 2

[0038] Based on Example 1, this example further specifies the specific material forms of the soluble ineffective transition phase, organic amine molecules, and metal ion source.

[0039] First, the soluble ineffective transition phase is a metal carbonate. Specifically, metal carbonates readily crystallize spontaneously under hydrothermal reaction conditions, serving as condensation nuclei to promote the dense growth of active substances; simultaneously, they dissolve rapidly under acidic conditions, achieving environmentally responsive generation and dissolution.

[0040] Secondly, the organic amine molecule is either a polyamine organic molecule or a nitrogen-containing chelating intercalating agent. Specifically, a polyamine organic molecule refers to an organic compound whose molecular structure contains two or more amino groups, and a nitrogen-containing chelating intercalating agent refers to an organic guest molecule that contains both coordinating nitrogen atoms and sufficient molecular length to widen the interlayer spacing. These two types of substances perform a dual function in the second intercalation treatment: the nitrogen atoms in the polyamine structure chelate with zinc ions, reducing the zinc ion insertion and extraction energy barrier; their molecular chains exert a physical support effect during co-intercalation, widening the interlayer spacing.

[0041] Finally, the metal ion is a calcium ion, the organic amine molecule is diethylenetriamine, and the metal carbonate is calcium carbonate. Specifically, the calcium ion has a suitable ionic radius and charge density, which allows it to stably enter the interlayer and exert a pillar effect during the first intercalation treatment; the diethylenetriamine (EDA) contains three coordinating nitrogen atoms, and its chelating ability and molecular length are well balanced; the formation and dissolution of calcium carbonate are well-regulated and reliable. In Example 4 below, the specific preparation operation of this preferred combination will be described in detail, and the following product names will be defined: the intermediate product containing calcium gluconate after only performing the first intercalation treatment will be denoted as Ca@VO / CP, and its crystals will be denoted as Ca@VO; the comparative product omitting calcium gluconate will be denoted as VO / CP, and its crystals will be denoted as VO; the final product of Ca@VO / CP after the second intercalation treatment will be denoted as Ca-EDA@VO / CP, and its crystals will be denoted as Ca-EDA@VO; the comparative product of VO / CP after the second intercalation treatment will be denoted as EDA@VO / CP, and its crystals will be denoted as EDA@VO. To empirically demonstrate the actual occurrence of "calcium carbonate dissolution" and "Ca-EDA co-intercalation" in this preferred combination, this embodiment combines the following... Figure 3 The XRD and ICP-MS data shown were verified. The XRD patterns showed that the intermediate product, which underwent only the first intercalation treatment, had obvious characteristic diffraction peaks of calcium carbonate, and all of its diffraction peaks could be matched to the monoclinic phase standard card.

[0042] To further verify the actual existence and evolution of each component in the above-mentioned preferred combination at the microstructural level, this embodiment systematically verified the results using multiple characterization methods, including FTIR, Raman, XPS, and TG-FTIR. In the FTIR spectrum, the absorption peaks at 540, 780, and 990 cm⁻¹ were attributed to the VO bond bending vibration, the VOV bridge symmetric stretching vibration, and...

[0043]

[0044] Example 3

[0045] Based on Example 1 or Example 2, this example further defines the macroscopic structural morphology of the electrode. The method also includes immersing carbon paper as a substrate into the reaction system, allowing the vanadium-based layered electrode material to grow in situ on the surface of the carbon paper, forming a self-supporting electrode structure.

[0046] Specifically, a self-supporting electrode structure refers to an integrated structure formed by the direct growth of active materials on a conductive substrate, eliminating the need for binders and metal current collectors required in traditional electrode fabrication. Carbon paper is immersed in a hydrothermal reaction system containing a vanadium-based layered oxide precursor and an intercalating agent. With the two-step intercalation process, the layered electrode material nucleates in situ on the surface of the three-dimensional porous network of the carbon paper and gradually grows. For example... Figure 2 As shown, SEM characterization results indicate that the active material is uniformly coated on the surface of the carbon fiber, forming a fluffy flower-like crystal cluster, and penetrates deep into the fiber intersections inside the carbon paper, making full use of the three-dimensional space of the carbon paper.

[0047]

[0048] Example 4

[0049] Based on Example 2 or Example 3, this example further limits the process parameters of the two-step intercalation process and the source of raw materials in the first intercalation process.

[0050] First, the temperature of the first intercalation treatment is 110°C to 130°C, and the time is 1 hour to 3 hours. Specifically, the core objective of the first intercalation treatment is to achieve effective intercalation of metal ions and sufficient generation of soluble ineffective transition phase. In this embodiment, the preferred parameters are a reaction at 120°C for 2 hours. In the preferred operation of the first intercalation treatment, 2 mmol of calcium metavanadate and 2.4 mmol of soluble carbonate are dissolved in 40 mL of deionized water and stirred for 15 minutes; then 1 mmol of calcium gluconate is added, and stirring is continued for 3 minutes; the prepared mixed solution is transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE), and carbon paper (CP) is immersed in the bottom of the high-pressure reactor as a substrate, and heated at 120°C for 2 hours; after naturally cooling to room temperature, it is taken out, rinsed several times with ethanol and deionized water, and finally dried in an oven at 60°C for 12 hours to obtain the intermediate product Ca@VO / CP, and the crystals grown on it are denoted as Ca@VO. In contrast, if the addition of calcium gluconate is omitted in the above operation, i.e., only 2 mmol of calcium metavanadate and 2.4 mmol of soluble carbonate are dissolved in 40 mL of deionized water for hydrothermal reaction, while keeping other conditions the same, the resulting product is denoted as VO / CP, and the crystals grown on it are denoted as VO. This comparative product does not contain calcium ion intercalation, nor does it generate an ineffective transition phase of calcium carbonate. Its active material growth density is significantly lower than that of the calcium-containing sample, and the interlayer spacing remains at the original level of approximately 0.98 nm.

[0051] The second intercalation treatment is carried out at a temperature of 170°C to 190°C for 0.5 to 2 hours, and at a pH of 2 to 4. Specifically, the second intercalation treatment needs to simultaneously complete three tasks: organic amine molecule intercalation, dissolution of metal carbonates, and prevention of layered framework collapse. A pH of 2 to 4 is a necessary condition for realizing the "use first, dissolve later" mechanism: metal carbonates are stable in weakly acidic or neutral environments and only dissolve rapidly in strongly acidic environments, but if the pH is too low, it will destroy the layered oxide framework. In this embodiment, the preferred parameters are a reaction at 180°C for 1 hour and a pH of 3. In the preferred operation of the second intercalation treatment, 28 mmol of diethylenetriamine (EDA) was dispersed in 40 mL of deionized water, and the pH was adjusted to pH 3 with acetic acid. The pH-adjusted solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave, and the Ca@VO / CP obtained in the first step was immersed in the bottom of the autoclave and heated at 180°C for 1 hour. After naturally cooling to room temperature, it was removed, rinsed several times with ethanol and deionized water, and dried in an oven at 60°C for 12 hours to obtain the final product Ca-EDA@VO / CP. The crystals grown on it are denoted as Ca-EDA@VO. Figure 3As shown, under these conditions, the characteristic peaks of calcium carbonate significantly weakened or even disappeared in the XRD pattern, and the interlayer spacing was successfully expanded to 1.12 nm. In contrast, if VO / CP underwent a second intercalation treatment under the same conditions as Ca@VO / CP, the resulting product is denoted as EDA@VO / CP, and the crystals grown on it are denoted as EDA@VO. This comparative product only underwent single intercalation modification of EDA molecules and did not have the support effect of calcium ions; therefore, its interlayer spacing expansion and structural stability were inferior to those of Ca-EDA@VO / CP.

[0052] Secondly, the metal ion source includes soluble calcium salts and carbon-containing calcium complexes; the soluble calcium salts include calcium metavanadate, and the carbon-containing calcium complexes include calcium gluconate. Specifically, the soluble calcium salts (such as calcium metavanadate) provide free calcium ions to participate in interlayer intercalation and exert a supporting effect, while also providing a vanadium source to form the basis for the growth of vanadium-based basal oxide precursors; the carbon-containing calcium complexes (such as calcium gluconate) gradually hydrolyze and release calcium ions under hydrothermal conditions. The released carbon-containing organic ligands decompose or transform under high-temperature hydrothermal conditions, combining with free calcium ions and carbonate sources in the system to generate metal carbonates as condensation nuclei in situ. The two work synergistically to achieve the synchronization of "intercalation ion supply" and "condensation nuclei carbon source supply".

[0053] Example 5

[0054] This embodiment provides a vanadium-based morphological electrode material, the core structural feature of which is: it includes a vanadium-based morphological oxide matrix, the interlayers of the vanadium-based morphological oxide matrix contain metal ions and organic amine molecules co-intercalated, and the vanadium-based morphological electrode material does not contain a soluble ineffective transition phase.

[0055] Specifically, metal ions (such as calcium ions) act as pillars in the interlayer, expanding the oxide layers and inhibiting their collapse; organic amine molecules (such as diethylenetriamine) enter the interlayer in synergy with nitrogen-containing coordinating groups, further increasing the interlayer spacing and generating a chelating affinity for zinc ions, thus lowering the zinc ion migration barrier. The co-intercalation of these two types of molecules significantly increases the interlayer spacing from approximately 0.98 nm to 1.12 nm. Simultaneously, the characteristic of "free from soluble ineffective transition phases" ensures that the ineffective transition phases, which act as condensation nuclei in the early stages of preparation, are completely dissolved and removed in the final product. This transforms the previously occupied space into unobstructed ion transport channels, eliminating ineffective mass and allowing zinc ions to fully utilize the active sites.

[0056]

[0057] The aforementioned structural features of "co-intercalation and absence of ineffective transition phases" significantly improve macroscopic electrochemical performance. Combined with... Figure 5The GCD and long-cycle test data shown are as follows: At 0.5 A / g, the specific capacity of the Ca-EDA@VO / CP electrode reaches 629.5 mAh / g, approximately six times that of the Ca@VO / CP electrode (100.9 mAh / g), and far exceeding that of VO / CP (338.1 mAh / g) and EDA@VO / CP (391.4 mAh / g). In rate performance tests, the specific capacities of the Ca-EDA@VO / CP electrode at 0.5, 1, 2, 4, and 5 A / g are 644.8, 580.9, 492.1, 366.6, and 318.2 mAh / g, respectively. After 5000 cycles at 1 A / g, the capacity retention is 80.3%, superior to VO / CP (65.4%) and EDA@VO / CP (65.3%). Figure 6 XPS and Raman characterization further confirmed the reversible insertion and extraction of zinc ions in the interlayer: CV tests showed that all samples exhibited two pairs of typical redox peaks, with approximately 1.0 V corresponding to V. 5 ⁺ / V 4 The ⁺ reaction corresponds to a V value at approximately 0.6 V. 4 ⁺ / V³⁺ transition; VO / CP and

[0058] Example 6

[0059] Based on Example 5, this example further refines and defines the microstructure parameters of the vanadium-based substrate electrode material. The interlayer spacing of the vanadium-based substrate electrode material is 1.0 nm to 1.2 nm, and the vanadium-based substrate electrode material has oxygen vacancies.

[0060] Specifically, an interlayer spacing range of 1.0 nm to 1.2 nm represents a balance between low diffusion barriers and high structural stability. This embodiment combines... Figure 3 The XRD and HRTEM data shown were determined: the XRD pattern shows a shift in the (001) diffraction peak of the final product, with a calculated interlayer spacing of 1.12 nm; the HRTEM image clearly shows a lattice fringe spacing of 1.12 nm. The corresponding SAED pattern indicates that the crystal on Ca-EDA@VO has single-crystal properties, and crystal ring data at 3.02 nm, 0.56 nm, and 1.12 nm can be observed.

[0061] Regarding the characteristics of oxygen vacancies, oxygen vacancies are a structural evolution product that inevitably accompanies the stepwise intercalation process of this invention. Their formation follows a "two-step reduction" path: in the first intercalation process, calcium ions enter the interlayer, leading to partial V... 5 ⁺ was restored to V 4⁺, accompanied by the generation of the first batch of oxygen vacancies; in the second intercalation treatment, EDA molecules, acting as organic reducing agents, further reduce the vanadium oxide framework, inducing the generation of the second batch of oxygen vacancies. For example... Figure 3 As shown, EPR test results indicate that the final product exhibits a significantly stronger oxygen vacancy characteristic signal at g=2.003 than other samples; XPS V 2p high-resolution spectrum shows that V in the final product 4 The relative content of ⁺ increased stepwise compared to the intermediate product, confirming the occurrence of a two-step reduction process. The presence of oxygen vacancies lowered the zinc ion insertion energy barrier and improved the structural reversibility of insertion and extraction. Combined with... Figure 5 The GITT test data shown indicate that the final product with a high concentration of oxygen vacancies exhibits a significantly higher zinc ion diffusion coefficient than the control group.

[0062] Example 7

[0063] This embodiment provides a zinc-ion battery. The zinc-ion battery includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode comprises a vanadium-based substrate electrode material as described in Embodiment 5 or Embodiment 6.

[0064] Specifically, the negative electrode is preferably zinc foil, the electrolyte is preferably a 2M aqueous solution of zinc trifluoromethanesulfonate, and the positive electrode is the vanadium-based substrate electrode material described in this invention. During the coin cell assembly process, the self-supporting positive electrode material is immersed in BP-2000 conductive carbon black dispersion (10 wt%), and then dried at 60°C for 1 hour to obtain the positive electrode sheet; the electrolyte is a 2M aqueous solution of zinc trifluoromethanesulfonate, the separator is a glass fiber membrane (Whatman GF / D), and the negative electrode is zinc foil; the above components are assembled into a CR 2032 type coin cell in the order of positive electrode sheet, separator, and zinc foil negative electrode stacking. Electrochemical tests are performed using a two-electrode system on an electrochemical workstation, including GCD, CV, and EIS tests; during the GITT test, the battery is charged and discharged at a current density of 0.05 A / g for 5 minutes, and then allowed to stand for 15 minutes to allow the voltage to reach equilibrium.

[0065] As detailed in Example 5, this vanadium-based substrate electrode material, with its core structural feature of "co-intercalation and no ineffective transition phase," exhibits synergistic advantages in zinc-ion battery systems, including rapid zinc-ion diffusion kinetics, excellent structural reversibility, and low charge transfer resistance. Figure 5 As shown, the battery using this cathode material has a specific capacity of 629.5 mAh / g at 0.5 A / g, a capacity retention of 80.3% after 5000 cycles at 1 A / g, and a charge transfer resistance of only about 20 Ω, all of which are significantly better than the control group.

[0066] Comparative Example 1

[0067] To demonstrate the irreplaceable nature of the second intercalation treatment for dissolving the ineffective transition phase and co-intercalating, this comparative design only performs the first intercalation treatment, omitting the step of introducing organic amine molecules to dissolve the ineffective transition phase, resulting in an intermediate product electrode (denoted as Ca@VO / CP) that retains a large amount of calcium carbonate.

[0068] Specifically, this comparative example only includes steps S100 and S200, introducing a calcium ion source to allow calcium ions to insert into the interlayer of the vanadium-based base oxide precursor, accompanied by the formation of an ineffective calcium carbonate transition phase. The surface and interlayer channels of the product in this comparative example are filled with a large number of undissolved bulk calcium carbonate crystals. For example... Figure 2 As shown in the image, the SEM image clearly shows the presence of obvious smooth, blocky calcium carbonate crystals in the comparative electrode.

[0069] This structural defect leads to a significant deterioration in macroscopic electrochemical performance. For example... Figure 5 As shown, at 0.5 A / g, the specific capacity of this comparative electrode is only 100.9 mAh / g, far lower than the 629.5 mAh / g of the final product. Physical performance tests also confirmed the negative impact of residual calcium carbonate: at 2 MPa, the vertical resistivity is as high as 16.1 mΩ·cm (compared to only 3.2 mΩ·cm for the final product), and the tensile strength is 37.21 MPa.

[0070] Furthermore, this comparative electrode exhibited an unusual capacity evolution trend of "increase followed by decrease" during long-cycle testing. After 5000 cycles at 1 A / g, the capacity retention rate reached 173.1%, with the capacity continuously increasing to 199.7% of the initial capacity during the first 2200 cycles. The microscopic mechanism of this anomaly can be explained by the synergistic effect of two slow hysteresis processes: firstly, in the high-potential region of the initial cycle, residual oxalate ions underwent slow electrochemical oxidative decomposition. The process gradually frees up the physical space occupied by calcium carbonate, slowly opening blocked ion transport channels and deliberately activating some "dead sites." Secondly, calcium ions released from the dissolution of calcium carbonate are slowly intercalated in situ into the vanadium oxide interlayer under the drive of an electric field, exerting a belated pillar effect. However, this "slow activation" and "in-situ intercalation," which rely on long-term cycling, has extremely low initial energy efficiency and lacks the synergistic chelation and pre-opening of interlayer spacing by organic amine molecules, leaving the structure at risk of collapse in later stages. This anomaly contrasts sharply with the high capacity and stable cycling of the final product achieved in one step, strongly demonstrating the irreplaceable role of the second intercalation in dissolving the ineffective transition phase and achieving organic amine co-intercalation.

[0071] Example 8

[0072] Building upon Example 7, this example further demonstrates the application of this vanadium-based substrate electrode material in flexible wearable energy storage scenarios. For example... Figure 7 As shown, Ca-EDA@VO / CP is used as the positive electrode and assembled with a semi-solid gel electrolyte and a zinc foil negative electrode to form a flexible pouch cell (SSGE-ZIBs).

[0073] Semi-solid gel electrolytes are electrolyte materials that combine ion conductivity and morphological stability, formed by crosslinking an aqueous electrolyte with a PVA polymer matrix. They contain 2M zinc trifluoromethanesulfonate as a zinc ion source. During assembly, 10.0 g of PVA is added to 100 mL of a 2M zinc trifluoromethanesulfonate aqueous solution and stirred vigorously at 80°C for 6 hours. After cooling to room temperature, a gel electrolyte is formed. The Ca-EDA@VO / CP positive electrode and glass fiber separator are immersed in this gel electrolyte for 15 minutes and dried at 60°C for 15 minutes. Using zinc foil as the negative electrode, the flexible pouch battery is assembled with the soaked and dried separator and positive electrode in a stacked sequence.

[0074] like Figure 7 As shown, at 0.5 A / g, the SSGE-ZIBs maintain a specific capacity of 453.5 mAh / g. Open-circuit voltage testing shows that the initial open-circuit voltage of the battery is 1.223 V; it drops to 1.219 V after a 90° bend; it still maintains 1.219 V after a 180° bend; and even after breakage, the voltage remains at 1.2173 V. This excellent safety, which prevents short circuits or voltage collapse under severe deformation and even breakage, is the result of the synergistic effect of the self-supporting positive electrode structure and the characteristics of the semi-solid gel electrolyte: the Ca-EDA@VO / CP positive electrode, relying on the three-dimensional carbon fiber network on the carbon paper substrate, gives the electrode flexibility and tensile strength, and the active material is firmly anchored on the carbon fiber surface in a fluffy flower-like crystal cluster; the semi-solid gel electrolyte can adaptively maintain close interfacial contact with the positive and negative electrodes during deformation, preventing voltage drops caused by partial open circuits.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention, as long as their essence still follows the synergistic intercalation and channel activation mechanism disclosed in the present invention, should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a vanadium-based substrate electrode material for zinc-ion batteries, characterized in that: Includes the following steps: Provides vanadium-based base oxide precursors; The vanadium-based oxide precursor is subjected to a first intercalation treatment, in which a metal ion source is introduced to allow metal ions to be inserted into the interlayer of the vanadium-based oxide precursor, accompanied by the formation of a soluble ineffective transition phase. A second intercalation treatment is performed on the product after the first intercalation treatment to introduce organic amine molecules, dissolve the soluble ineffective transition phase, and co-intercalate the organic amine molecules and the metal ions into the interlayer of the vanadium-based oxide precursor to obtain a vanadium-based electrode material.

2. The method for preparing the vanadium-based substrate electrode material according to claim 1, characterized in that: The soluble ineffective transition phase is a metal carbonate.

3. The method for preparing the vanadium-based substrate electrode material according to claim 2, characterized in that: The organic amine molecule is a polyamine organic molecule or a nitrogen-containing chelating intercalating agent.

4. The method for preparing the vanadium-based substrate electrode material according to claim 3, characterized in that: The metal ion is a calcium ion, the organic amine molecule is diethylenetriamine, and the metal carbonate is calcium carbonate.

5. The method for preparing the vanadium-based substrate electrode material according to claim 1, characterized in that: The method further includes immersing carbon paper as a substrate into the reaction system, so that the vanadium-based layered electrode material grows in situ on the surface of the carbon paper to form a self-supporting electrode structure.

6. The method for preparing the vanadium-based substrate electrode material according to claim 4, characterized in that: The temperature of the first intercalation process is 110°C to 130°C, and the time is 1 hour to 3 hours. The second intercalation treatment is carried out at a temperature of 170°C to 190°C for a time of 0.5 hours to 2 hours, and at a pH of 2 to 4.

7. The method for preparing the vanadium-based substrate electrode material according to claim 4, characterized in that: The metal ion source includes soluble calcium salts and calcium complexes containing carbon sources; the soluble calcium salts include calcium metavanadate, and the calcium complexes containing carbon sources include calcium gluconate.

8. A vanadium-based substrate electrode material, characterized in that: The material includes a vanadium-based morphological oxide matrix, wherein the interlayers of the vanadium-based morphological oxide matrix contain intercalation of metal ions and organic amine molecules, and the vanadium-based morphological electrode material does not contain a soluble ineffective transition phase.

9. The vanadium-based substrate electrode material according to claim 8, characterized in that: The vanadium-based morphological electrode material has an interlayer spacing of 1.0 nm to 1.2 nm and has oxygen vacancies.

10. A zinc-ion battery, comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that: The positive electrode comprises the vanadium-based layered electrode material according to claim 8.

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