Modified positive electrode structure, method for preparing the same, zinc vanadium battery, and method for preparing the same

Abstract

This invention provides a modified positive electrode structure, a method for preparing the same, a zinc-vanadium battery, and a method for preparing the same. [Solution] The zinc-vanadium battery comprises a modified positive electrode structure (including a positive electrode and a first modified layer), a separator, a negative electrode, and an aqueous electrolyte. The positive electrode contains aluminum covered with a carbon coating. The first modified layer is located on the positive electrode and contains 70-95 parts by weight of vanadium-based material, 3-45 parts by weight of conductive agent, and 3-45 parts by weight of binder. The separator is located on the first modified layer. The negative electrode contains zinc and is located on the separator. The positive electrode, the first modified layer, the separator, and the negative electrode are all in the aqueous electrolyte. In the X-ray diffraction pattern of the vanadium-based material measured by XRD using CuKα1 rays, the peak intensity at 2θ=8°±1.0° is I8, and the peak intensity at 2θ=20°±1.0° is I 20 In that case, I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 It satisfies ≤ 1.4.

Description

Technical Field

[0001] The present invention relates to a modified positive electrode structure and a method for preparing the same, and particularly to a modified positive electrode structure containing a modified vanadium-based material and a method for preparing the same. The present invention also relates to a zinc vanadium battery and a method for preparing the same, and particularly to a zinc vanadium battery containing a modified positive electrode structure and a method for preparing the same.

Background Art

[0002] Conventional batteries using zinc as the negative electrode have many structural and characteristic limitations. For example, the capacity per gram of a battery using zinc as the negative electrode is about 100 to 200 mAh / g, and there is still room for improvement. In addition, at the initial stage of charge and discharge of such a battery using zinc as the negative electrode, the discharge environment of the battery was not completely balanced, so the discharge reaction was unstable.

[0003] Furthermore, for example, in a battery using zinc as the negative electrode, zinc plating products gradually accumulate on the negative electrode during use, and further grow into dendritic crystals (also called dendrites) in the electrolyte. These dendrites pierce through the separator and cause battery failure.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to increase the capacity per gram of a battery using zinc as the negative electrode, the inventors of the present application recognize that zinc perchlorate (Zn(ClO4)2) or other zinc salts having higher cost or stronger acidity are often used as electrolytes in the technical field to which they belong. However, although this improvement method can improve the discharge performance of the battery, since the electrolyte becomes acidic and side reactions are likely to occur, the manufacturing difficulty of the battery increases and the process technology cost becomes relatively high.

Means for Solving the Problems

[0005] Therefore, some embodiments propose a modified positive electrode structure including a positive electrode and a first modification layer. The positive electrode includes aluminum covered with a carbon coating. The first modification layer is located on the positive electrode and includes 70-95 parts by weight of a vanadium-based material, 3-45 parts by weight of a conductive agent, and 3-45 parts by weight of a binder. In the X-ray diffraction pattern of the vanadium-based material measured by an X-ray diffractometer (XRD) using CuKα1 radiation, the peak intensity at 2θ = 8° ± 1.0° is I8, and the peak intensity at 2θ = 20° ± 1.0° is I 20 When it is 20 The ratio (I8 / I 20 ) satisfies 0 < I8 and I 20 ≤ 1.4.

[0006] In addition, some embodiments propose a method for preparing the above modified positive electrode structure, including a first homogenization step, a drying step, a second homogenization step, and a coating step. The first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a van -adium-based homogeneous mixture. The drying step includes freeze - drying or heat - drying the vanadium-based homogeneous mixture to obtain a vanadium-based material. The second homogenization step includes mixing the vanadium-based material, the conductive agent, and the binder and homogenizing them to obtain a first modified material. The coating step includes coating the first modified material on the positive electrode to form a first modification layer on the positive electrode, thereby obtaining a modified positive electrode structure.

[0007] In some embodiments, the above modified positive electrode structure further includes a second modification layer, and the second modification layer is located on the first modification layer. In some embodiments, the above second modification layer includes at least one selected from poly(3,4 - ethylenedioxythiophene) (PEDOT) and polyaniline (PANI).

[0008] Furthermore, some embodiments propose a method for preparing the modified cathode structure, comprising a first homogenization step, a drying step, a second homogenization step, a first coating step, and a second coating step. The first homogenization step includes mixing and homogenizing vanadium oxide, water, and hydrogen peroxide to obtain a vanadium-based homogeneous mixture. The drying step includes freeze-drying or heat-drying the vanadium-based homogeneous mixture to obtain a vanadium-based material. The second homogenization step includes mixing and homogenizing the vanadium-based material, a conductive agent, and a binder to obtain a first modified material. The first coating step includes coating the first modified material onto the cathode to form a first modified layer on the cathode. The second coating step includes coating the second modified material onto the first modified layer to form a second modified layer on the first modified layer. The modified cathode structure is obtained by including at least one selected from PEDOT and PANI in the second modified material.

[0009] Furthermore, some embodiments propose a zinc-vanadium battery comprising a modified cathode structure (including a cathode and a first modified layer), a separator, a negative electrode, and an aqueous electrolyte. The cathode contains aluminum covered with a carbon coating. The first modified layer is located on the cathode and contains 70-95 parts by weight of vanadium-based material, 3-45 parts by weight of conductive agent, and 3-45 parts by weight of binder. The separator is located on the first modified layer. The negative electrode contains zinc and is located on the separator. The cathode, first modified layer, separator, and negative electrode are in an aqueous electrolyte. In the X-ray diffraction pattern of the vanadium-based material measured by XRD using CuKα1 rays, the peak intensity at 2θ = 8° ± 1.0° is I8, and the peak intensity at 2θ = 20° ± 1.0° is I 20 In that case, I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 It satisfies ≤ 1.4.

[0010] Some embodiments also propose a method for preparing the above zinc vanadium battery, which includes a first homogenization step, a drying step, a second homogenization step, a coating step, and an assembly step. The first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture. The drying step includes freeze-drying or heat-drying the vanadium-based homogeneous mixture to obtain a vanadium-based material. The second homogenization step includes mixing the vanadium-based material, a conductive agent, and a binder and homogenizing them to obtain a first modified material. The coating step includes coating the first modified material on the positive electrode to form a first modified layer on the positive electrode. The assembly step includes sequentially assembling a separator and a negative electrode on the first modified layer, and immersing the positive electrode, the first modified layer, the separator, and the negative electrode in an aqueous electrolyte to obtain a zinc vanadium battery.

[0011] Also, some embodiments further propose a zinc vanadium battery including a modified positive electrode structure (including a positive electrode, a first modified layer, and a second modified layer), a separator, a negative electrode, and an aqueous electrolyte. The positive electrode includes aluminum covered with a carbon coat. The first modified layer is located on the positive electrode and includes 70 to 95 parts by weight of a vanadium-based material, 3 to 45 parts by weight of a conductive agent, and 3 to 45 parts by weight of a binder. The second modified layer is located on the first modified layer and includes at least one selected from PEDOT and PANI. The separator is located on the second modified layer. The negative electrode includes zinc and is located on the separator. The positive electrode, the first modified layer, the second modified layer, the separator, and the negative electrode are in the aqueous electrolyte. In the X-ray diffraction pattern of the vanadium-based material measured by XRD using CuKα1 radiation, when the peak intensity at 2θ = 8° ± 1.0° is I8 and the peak intensity at 2θ = 20° ± 1.0° is I 20 when taken, the ratio (I8 / I 20 ) of I8 to I 20 ) satisfies 0 < I8 / I 20 ≦1.4.

[0012] Furthermore, some embodiments propose a method for preparing the above-mentioned zinc-vanadium battery, which includes a first homogenization step, a drying step, a second homogenization step, a first coating step, a second coating step, and an assembly step. The first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture. The drying step includes freeze-drying or heat-drying the vanadium-based homogeneous mixture to obtain a vanadium-based material. The second homogenization step includes mixing the vanadium-based material, a conductive agent, and a binder and homogenizing them to obtain a first modified material. The first coating step includes coating the first modified material onto the positive electrode to form a first modified layer on the positive electrode. The second coating step includes coating the second modified material, which includes at least one selected from PEDOT and PANI, onto the first modified layer to form a second modified layer on the first modified layer. The assembly process includes sequentially assembling the separator and negative electrode on the second modified layer, and immersing the positive electrode, first modified layer, second modified layer, separator, and negative electrode in an aqueous electrolyte to obtain a zinc vanadium battery.

[0013] The following drawings are used for illustrative purposes only to provide a more comprehensive understanding of some embodiments of the present invention, but are not intended to limit the scope of the invention by these embodiments. [Brief explanation of the drawing]

[0014] [Figure 1A] This is a schematic diagram of a zinc-vanadium battery including a modified positive electrode structure according to several embodiments. [Figure 1B] This is a schematic diagram of a zinc-vanadium battery including a modified positive electrode structure according to several embodiments. [Figure 2A] Figure 1A is a flowchart illustrating a method for preparing a zinc-vanadium battery according to several embodiments. [Figure 2B] Figure 1B is a flowchart illustrating a method for preparing a zinc-vanadium battery according to several embodiments. [Figure 3A]This is the X-ray diffraction pattern of Comparative Example 1 (known to the inventors of this application), a vanadium-based material, measured by XRD using CuKα1 radiation. [Figure 3B] This is the X-ray diffraction pattern of the vanadium-based material of Example 1 (several embodiments of the present invention) measured by XRD using CuKα1 rays. [Figure 3C] This is the X-ray diffraction pattern of the vanadium-based material of Example 2 (another embodiment of the present invention) measured by XRD using CuKα1 rays. [Figure 4] This is a comparison chart of the discharge capacities of the zinc-vanadium battery of Comparative Example 2 (using zinc foil for the positive electrode) and the zinc-vanadium batteries of Examples 3 to 8 (using carbon-coated aluminum foil for the positive electrode). [Figure 5] This is a comparison chart of the average lifespan of the zinc-vanadium battery of Comparative Example 2 (using zinc foil for the positive electrode) and the zinc-vanadium batteries of Examples 3 to 8 (using carbon-coated aluminum foil for the positive electrode). [Modes for carrying out the invention]

[0015] The term "approximately" may vary depending on the technology and within the range of deviations understood by those skilled in the art. The term "approximately" in relation to a specific distance or dimension may be interpreted as not excluding a small deviation from the specified distance or dimension. For example, the term "approximately" may include a deviation of up to 10% of the specified quantity, but embodiments of this disclosure are not limited thereto. The term "approximately" in relation to a numerical value x may indicate x ± 5 or 10% of the specified quantity, but embodiments of this disclosure are not limited thereto.

[0016] Referring to Figure 1A, Figure 1A is a schematic diagram of a zinc-vanadium battery 1a including a modified cathode structure according to several embodiments. In Figure 1A, the modified cathode structure includes a cathode 10 and a first modified layer 12. The cathode 10 includes aluminum foil covered with a carbon coating, and the first modified layer 12 is located on the cathode 10 and includes a vanadium-based material, a conductive agent, and a binder. In the X-ray diffraction pattern of the vanadium-based material measured by an X-ray diffractometer (XRD) using CuKα1 rays, the peak intensity at 2θ = 8° ± 1.0° is I8, and the peak intensity at 2θ = 20° ± 1.0° is I 20 In that case, I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 The condition ≤1.4 is satisfied (details will be described later). In Figure 1A, the zinc-vanadium battery 1a includes the modified positive electrode structure (including the positive electrode 10 and the first modified layer 12), a separator 14, a negative electrode 16, and an aqueous electrolyte 18. The separator 14 is located on the first modified layer 12, and the negative electrode 16 contains zinc (Zn) and is located on the separator 14. The positive electrode 10, the first modified layer 12, the separator 14, and the negative electrode 16 are all in the aqueous electrolyte 18. As a result, the zinc-vanadium battery 1a including the modified positive electrode structure can have more stable charge and discharge performance, higher battery capacity, and a longer lifespan compared to a zinc-vanadium battery known to the inventors (without the modified positive electrode structure) (details will be described later).

[0017] The positive electrode 10 may be a metal foil or a metal material having a porous structure (e.g., a metal mesh). The positive electrode 10 may be a metal foil containing a carbon coating (e.g., aluminum foil covered with a carbon coating, i.e., "carbon-coated aluminum foil" as used herein), anodic aluminum oxide (AAO), or a metal material having a porous structure (e.g., aluminum mesh covered with a carbon coating with a mesh size of about 100 to 500 nm). The thickness of the positive electrode 10 may be, but is not limited to, 5 to 50 μm, or for example, about 10 to 50 μm. The thickness may be adjusted according to requirements such as physical properties such as tensile strength. The thickness of the carbon coating is about 1 to 5 μm. In some embodiments, the positive electrode 10 is a metal foil containing a carbon coating of a commercially available specification, for example, aluminum foil (about 20 μm thick) covered with a carbon coating (about 1 to 5 μm thick).

[0018] The first modified layer 12 contains 70 to 95 parts by weight of vanadium-based material, 3 to 45 parts by weight of conductive agent, and 3 to 45 parts by weight of binder. The total weight of the vanadium-based material, conductive agent, and binder is not limited to 100 parts by weight, but can be adjusted to less than 100 parts by weight or more than 100 parts by weight as needed. In some embodiments, the weights of the vanadium-based material, conductive agent, and binder are 80 parts by weight, 10 parts by weight, 10 parts by weight, or 90 parts by weight, 5 parts by weight, 5 parts by weight, or 92 parts by weight, 5 parts by weight, and 3 parts by weight, respectively, but are not limited to these. If the vanadium-based material, conductive agent, and binder are not added in the respective weight parts described above, even if the modified cathode structure contains the vanadium-based material, at least one of the charge / discharge performance, battery capacity, and lifespan of a zinc-vanadium battery manufactured according to the weight ratio cannot be significantly better than that of a zinc-vanadium battery known to the inventors (without the above-mentioned modified cathode structure). The thickness of the first modified layer 12 is 50 to 90 μm, but is not limited thereto.

[0019] The vanadium-based materials described above, as measured by XRD using CuKα1 radiation, showed a peak intensity of I8 at 2θ = 8° ± 1.0° and a peak intensity of I8 at 2θ = 20° ± 1.0° in their X-ray diffraction patterns. 20 In that case, I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 The condition ≤ 1.4 is satisfied (details below). In some embodiments, I8 / I 20 is 1.1 ≤ I8 / I 20 Satisfying ≤1.4. In some embodiments, I8 / I 20 is 1.13 ≤ I8 / I 20 The condition satisfies ≤1.35. In some embodiments, I8 / I 20 I8 is any value between 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 0 and any of the above values, or any value between any two of the above values. In some embodiments, I8 refers to the peak intensity at 2θ = 8° ± 0.5°, and I 20 This refers to the peak intensity at 2θ = 20° ± 0.5°. I8 / I for vanadium-based materials. 20 If the value is not within the above range (for example, below the lower limit of the above range or above the upper limit of the above range), even if the modified cathode structure contains vanadium-based material, at least one of the charge / discharge performance, battery capacity, and lifespan of a zinc-vanadium battery manufactured according to the weight ratio cannot be significantly better than the performance of a zinc-vanadium battery known to the inventors (without the above modified cathode structure).

[0020] Referring to Figure 2A, Figure 2A is a flowchart of a method 2a for preparing a zinc-vanadium battery 1a shown in Figure 1A according to several embodiments. The vanadium-based material may be a vanadium-based material prepared through some steps of method 2a in Figure 2A, for example, obtained through step S20 or steps S20-S21 in Figure 2A (details will be described later). Therefore, the vanadium-based material may include vanadium oxide or its derivatives, which are the initial materials used in step S20 in Figure 2A, and the vanadium-based material I8 and I 20 The ratio to the aforementioned relationship is also given by, for example, 0 <I8 / I 20 The above vanadium oxide satisfies ≤ 1.4. x O y The compound may contain any compound represented by (x and y are both positive numbers), and the possibility of doping with impurities that do not affect the physicochemical properties of vanadium oxide is not ruled out. For example, the vanadium oxide or its derivatives may include V2O5, VO2, NaV3O8·1.5H2O, LiV3O8, Na2V6O 16 • 1.63H2O, Fe5V 15 O 39 (OH)9·9H2O, Zn3V2O7(OH)2·2H2O, and a mixture of two or more of their derivatives may be used.

[0021] The conductive agent may include at least one selected from conductive carbon black and carbon nanotubes (CNTs). The conductive carbon black may be any commercially available conductive carbon black, but may include at least one selected from, for example, acetylene black, Ketjenblack, Super P, XC-72, N220, N330, N550, S204, FW200, VGCF, and KS6. In other words, the conductive carbon black may be a mixture of one or more of acetylene black, Ketjenblack, Super P, XC-72, N220, N330, N550, S204, FW200, VGCF, and KS6. In some embodiments, the conductive agent includes Super P or a mixture thereof. The above-mentioned CNTs may be various commercially available CNTs, and may include, for example, at least one selected from single-walled carbon nanotubes (SCNTs) and multi-walled carbon nanotubes (MCNTs). In other words, the CNTs may be a mixture of one or more types of SCNTs and MCNTs.

[0022] The above binder may contain at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polyimide (PI). In other words, the binder may be a mixture of one or more of PVDF, PTFE, CMC, SBR, and PI. In some embodiments, the binder contains at least one selected from PVDF and PTFE. In some embodiments, the binder contains PVDF or a mixture thereof.

[0023] Please refer to Figure 1A. The separator 14 may include at least one selected from cellulose, synthetic fibers, and glass fibers. Examples of synthetic fibers include polyester fibers or polyaramid fibers. In some embodiments, the separator 14 includes at least one selected from cellulose and glass fibers. In some embodiments, the separator 14 has corresponding usage combinations depending on different aqueous electrolytes 18 (details will be described later). The thickness of the separator 14 is 30 to 400 μm, but is not limited thereto.

[0024] Please continue to refer to Figure 1A. The negative electrode 16 may be a metal foil or a metal material having a porous structure (e.g., a metal mesh). The negative electrode 16 may be a metal foil containing zinc (e.g., zinc foil) or a metal material having a porous structure (e.g., a zinc mesh with a mesh size not exceeding 1 μm). The purity of the zinc is, for example, 95 wt% or more relative to the metal foil or metal material. The thickness of the negative electrode 16 may be, but is not limited to, 10 to 50 μm, or for example, about 20 to 50 μm. In some embodiments, the negative electrode 16 is a metal foil containing zinc (e.g., zinc foil), and the positive electrode 10 is a metal foil containing a carbon coating (e.g., carbon-coated aluminum foil).

[0025] Please continue to refer to Figure 1A. The aqueous electrolyte 18 may be various organic or inorganic salts that dissolve in water and release the same metal ions as the metal contained in the negative electrode 16. For example, when a metal foil containing zinc is used for the negative electrode 16, the aqueous electrolyte 18 must be selected to contain an organic or inorganic salt that can release zinc ions (the same as the metallic zinc ions contained in the negative electrode 16) after dissolving in water. In this case, the aqueous electrolyte 18 may contain at least one selected from, for example, zinc triflate (Zn(OTf)2) and zinc sulfate (ZnSO4).

[0026] In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing water and Zn(OTf)2, and the weight ratio of water to Zn(OTf)2 may be, but is not limited to, 1:1 to 7:3, for example about 6:4 or 57.72:42.28. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing water, Zn(OTf)2 and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(CF3SO2)2), and the weight ratio of water to Zn(OTf)2 and LiN(CF3SO2)2 may be, but is not limited to, 1.5:1:0.01 to 0.30 or 1.4:1:0.01 to 0.28, for example about 1.5:1:0.05 or 1.4:1:0.05. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing Zn(OTf)2. In other embodiments, the aqueous electrolyte 18 is an aqueous solution containing 1 to 5 M of Zn(OTf)2. The above 1 to 5 M of Zn(OTf)2 is, for example, 2 M of Zn(OTf)2. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing Zn(OTf)2 and 0.1 to 1 M of LiN(CF3SO2)2. In yet another embodiment, the aqueous electrolyte 18 is an aqueous solution containing 2 M of Zn(OTf)2 and 0.1 to 1 M of LiN(CF3SO2)2. The above 0.1 to 1 M of LiN(CF3SO2)2 is, for example, one selected from 0.125 M, 0.25 M, 0.5 M, and 0.75 M of LiN(CF3SO2)2. For example, the above LiN(CF3SO2)2 is 0.125 M of LiN(CF3SO2)2.

[0027] In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing water and ZnSO4, and the weight ratio of water to ZnSO4 may be, but is not limited to, 1:1 to 7:3, for example about 6:4 or 57.72:42.28. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing water, ZnSO4 and ammonium sulfate ((NH4)2SO4), and the weight ratio of water to ZnSO4 to (NH4)2SO4 may be, but is not limited to, 1.5:1:0.03 to 0.18 or 1.4:1:0.02 to 0.17, for example 1.5:1:0.05 or 1.4:1:0.05. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing ZnSO4. In other embodiments, the aqueous electrolyte 18 is an aqueous solution containing 0.5 to 3 M ZnSO4. The above 0.5-3M ZnSO4 is, for example, one selected from 0.5, 1, 2, 2.5, and 3M ZnSO4. In some embodiments, the aqueous electrolyte 18 is an aqueous solution containing ZnSO4 and 0.1-0.3M (NH4)2SO4. In yet another embodiment, the aqueous electrolyte 18 is an aqueous solution containing 2M ZnSO4 and 0.1-0.3M (NH4)2SO4. The above 0.1-0.3M (NH4)2SO4 is, for example, one selected from 0.125M and 0.25M (NH4)2SO4. For example, the above (NH4)2SO4 is 0.25M (NH4)2SO4.

[0028] In some embodiments, the separator 14 has a corresponding combination of uses depending on the different aqueous electrolyte 18. For example, if the aqueous electrolyte 18 is an aqueous solution containing water and Zn(OTf)2, a separator containing glass fibers may be selected as the separator 14. Alternatively, if the aqueous electrolyte 18 is an aqueous solution containing water and ZnSO4, a separator containing cellulose may be selected as the separator 14. As a result, in some embodiments, a zinc vanadium battery 1a including the above-mentioned specific combination of separator 14 and aqueous electrolyte 18 can have relatively superior battery performance compared to a zinc vanadium battery that does not select the above-mentioned specific combination of separator 14 and aqueous electrolyte 18.

[0029] Next, please refer to Figure 2A in conjunction with Figure 1A. Figure 2A shows a method for preparing a modified cathode structure and a method 2a for preparing a zinc vanadium battery 1a including the modified cathode structure. It should be noted that before preparing a zinc vanadium battery 1a including the modified cathode structure, it is necessary to first prepare the modified cathode structure. In other words, the method for preparing the modified cathode structure can be included in the method 2a for preparing a zinc vanadium battery 1a including the modified cathode structure. For example, the method for preparing the modified cathode structure may be steps S20 to S23 of method 2a, and the method 2a for preparing a zinc vanadium battery 1a including the modified cathode structure can be completed by assembling the modified cathode structure, separator 14 and negative electrode 16 obtained through steps S20 to S23 according to step S25a, and immersing these structures in an aqueous electrolyte 18.

[0030] For further details, please refer to Figure 2A. The method 2a for preparing a zinc vanadium battery 1a including a modified cathode structure may include steps S20-S23 and S25a.

[0031] Step S20 is a first homogenization step, which includes mixing and homogenizing vanadium oxide, water, and hydrogen peroxide to obtain a vanadium-based homogeneous mixture. For example, step S20 involves homogenizing (e.g., stirring) vanadium oxide, water, and hydrogen peroxide in a weight ratio of 7:120:2 to 7:120:12 for 12 to 15 hours under normal conditions to obtain a vanadium-based homogeneous mixture. The above normal conditions may be a process environment with a humidity of 40% or less. In some embodiments, step S20 is carried out at room temperature and atmospheric pressure. In some embodiments, the weights of vanadium oxide, water, and hydrogen peroxide are 35g, 600g, and 10g (i.e., 7:120:2), or 35g, 600g, and 20g (i.e., 7:120:4), or 35g, 600g, and 60g (i.e., 7:120:12). In other words, the weight ratio of water to hydrogen peroxide may be 60:1, 30:1, or 10:1. Specific embodiments of the vanadium oxide described above can be found in the preceding text, so a detailed explanation is omitted here. The water and hydrogen peroxide may be, but are not limited to, commercially available or laboratory-grade water and hydrogen peroxide that are available to a person with ordinary skill in the art. In step S20, the reaction between hydrogen peroxide and vanadium oxide forms a layered structure in which the crystals of vanadium oxide itself are stacked, and the interlayer spacing of these layered structures is expanded and further enlarged. Because the interlayer spacing between these layered structures is enlarged, it is possible to provide greater charge storage during the subsequent charge-discharge process of the zinc-vanadium battery 1a, and the difficulty of ion exchange between these layered structures can also be reduced. This makes it possible to extend the battery life of the zinc-vanadium battery 1a by avoiding the problem of power decay after multiple charge-discharge cycles in some embodiments.

[0032] Step S21 is a drying step that includes further freeze-drying or heat-drying the vanadium-based homogeneous mixture obtained in step S20 to obtain a vanadium-based material.

[0033] In some embodiments, the heating and drying in step S21 involves first removing the solvent contained in the vanadium-based homogeneous mixture obtained in step S20, then placing it in an oven and drying it under vacuum and high temperature to obtain a vanadium-based material. The above step of removing the solvent contained in the vanadium-based homogeneous mixture can be carried out by a filtration step and / or a concentration step. The above filtration step can be carried out by, for example, vacuum filtration, gravity filtration, pressure filtration, or centrifugal filtration, but is not limited to these. The above concentration step can be carried out by, for example, cyclotron concentration or reduced-pressure concentration, but is not limited to these. In some embodiments, the above step of drying the vanadium-based material under vacuum and high temperature can be carried out by heating it to about 50-70°C (e.g., about 60°C) and maintaining that temperature overnight. In some embodiments, in step S20, an organic solvent (e.g., N-methyl-2-pyrrolidone (NMP)) is added to the vanadium-based material to improve the vacuum filtration efficiency by substituting NMP for water, and then the process proceeds to step S21, where the material is dried, for example, by the above-described heating and drying method, to obtain the vanadium-based material. In some embodiments, the vanadium-based material obtained by the above-described heating and drying method can be further pulverized as appropriate to further refine the vanadium-based material that has aggregated after drying.

[0034] In some embodiments, freeze-drying in step S21 means first freezing the vanadium-based homogeneous mixture obtained in step S20 into a frozen state before heating and drying, then applying a vacuum and heating to directly sublimate the water molecules in the vanadium-based homogeneous mixture from a solid state. Therefore, in some embodiments, drying by the above freeze-drying method can avoid the aggregation phenomenon of the vanadium-based material after drying and provide a softer dried powder.

[0035] After completing step S21, the obtained vanadium-based material can be measured by XRD using CuKα1 radiation. In the X-ray diffraction pattern of this vanadium-based material, a peak of intensity I8 appears at 2θ = 8° ± 1.0°, and a peak of intensity I8 appears at 2θ = 20° ± 1.0°. 20 A peak appears, and I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 ≤ 1.4, for example 1.1 ≤ I8 / I 20 The condition ≤1.4 is satisfied. In some embodiments, the above XRD measurement allows for early confirmation of whether the vanadium-based material prepared in step S21 can subsequently be used in the manufacture of the zinc-vanadium battery 1a, thereby saving manufacturing costs.

[0036] Step S22 is a second homogenization step that includes mixing the vanadium-based material, conductive agent, and binder obtained in step S21 and homogenizing them to obtain a first modified material. For example, step S22 involves homogenizing (e.g., stirring) the vanadium-based material, conductive agent, and binder in a weight ratio of 70-95:3-45:3-45 under normal conditions for 1-15 hours to obtain the first modified material. The above normal conditions may be a process environment with a humidity of 40% or less. In some embodiments, step S22 is carried out at room temperature and atmospheric pressure. In some embodiments, the weights of the vanadium-based material, conductive agent, and binder are 70-95 parts by weight, 3-45 parts by weight, and 3-45 parts by weight, respectively. For example, the weights of the vanadium-based material, conductive agent, and binder are 80 parts by weight, 10 parts by weight, and 10 parts by weight, respectively. Specific embodiments of the vanadium-based material, conductive agent, and binder described above can be found in the previously mentioned content, so a detailed explanation is omitted here. In some embodiments, the vanadium-based material, conductive agent, and binder from step S22 are homogenized by adding them to an organic solvent (e.g., NMP), which ensures that the vanadium-based material, conductive agent, and binder are sufficiently and uniformly dispersed by the organic solvent, preventing aggregation and particle generation. In some embodiments, the first modified material obtained in step S22 must satisfy particle size requirements; for example, the particle size of the first modified material must be less than 60 μm.

[0037] Step S23 is a first coating step that includes coating the first modified material obtained in step S22 onto the positive electrode 10 (Figure 1A) to form a first modified layer 12 on the positive electrode 10. For example, the first modified material can be coated onto the positive electrode 10 using a frame-type four-sided applicator. In some embodiments, after coating the first modified material onto the positive electrode 10, the first modified material and the positive electrode 10 can be subjected to a further drying step to complete the first modified layer 12. For example, step S23 is completed by drying the first modified layer 12 on the positive electrode 10 and the positive electrode 10 at about 80-100°C (e.g., about 100°C) for about 1 hour. Specific embodiments of the positive electrode 10 and the first modified layer 12 can be found in the above description, so a detailed explanation is omitted here.

[0038] After completing step S23 in Figure 2A, the first modified layer 12 on the obtained positive electrode 10 can be used as the modified positive electrode structure described above. In some embodiments, a zinc-vanadium battery 1a can be obtained by further performing step S25a on the obtained modified positive electrode structure according to Figure 2A. Alternatively, in some embodiments, a zinc-vanadium battery 1b can be obtained by further performing steps S24 and S25b on the obtained positive electrode 10's first modified layer 12 according to Figure 2B (details will be described later).

[0039] Please refer to Figure 2A. Step S25a is an assembly step that includes assembling the separator 14 and the negative electrode 16 sequentially on the first modified layer 12, and immersing the positive electrode 10, the first modified layer 12, the separator 14, and the negative electrode 16 in an aqueous electrolyte 18 (Figure 1A) to obtain a zinc vanadium battery 1a. For example, after assembling the modified positive electrode structure (including the positive electrode 10 and the first modified layer 12), the separator 14, and the negative electrode 16 sequentially, the final zinc vanadium battery 1a can be obtained by sealing it with a hydraulic press in accordance with the specifications for a CR2032 button cell battery. Specific embodiments of the positive electrode 10, the first modified layer 12, the separator 14, the negative electrode 16, and the aqueous electrolyte 18 can be found in the previously described content, so a detailed explanation is omitted here. In some embodiments, the thickness of the positive electrode 10 is approximately 5 to 50 μm, the thickness of the first modified layer 12 is approximately 70 to 90 μm, the thickness of the separator 14 is approximately 30 to 400 μm, and the thickness of the negative electrode 16 is approximately 10 to 50 μm.

[0040] Referring to Figure 1B, Figure 1B is a schematic diagram of a zinc-vanadium battery 1b including a modified positive electrode structure according to several embodiments. The zinc-vanadium battery 1b shown in Figure 1B is substantially the same as the zinc-vanadium battery 1a shown in Figure 1A, the main difference being that the zinc-vanadium battery 1b shown in Figure 1B further includes a second modified layer 13 located on the first modified layer 12, which contains at least one selected from poly(3,4-ethylenedioxythiophene) (PEDOT) and polyaniline (PANI). Therefore, the zinc-vanadium battery 1b shown in Figure 1B includes the modified positive electrode structure (including the positive electrode 10, the first modified layer 12, and the second modified layer 13), a separator 14, a negative electrode 16, and an aqueous electrolyte 18. The separator 14 is located on the second modified layer 13, and the negative electrode 16 contains Zn and is located on the separator 14. The positive electrode 10, the first modified layer 12, the second modified layer 13, the separator 14, and the negative electrode 16 are all located in an aqueous electrolyte 18. As a result, compared to zinc vanadium batteries known to the inventors (without the above modified positive electrode structure), the zinc vanadium battery 1b including the above modified positive electrode structure can have more stable charge and discharge performance, higher battery capacity, and a longer lifespan (details will be described later).

[0041] Since the specific embodiments of the positive electrode 10 and the first modified layer 12 shown in Figure 1B can be found by referring to the above description, a detailed explanation is omitted here.

[0042] Next, referring to Figure 2B, Figure 2B is a flowchart of a method 2b for preparing the zinc-vanadium battery 1b shown in Figure 1B according to several embodiments. The method 2b shown in Figure 2B is substantially the same as the method 2a shown in Figure 2A, the main difference being that, for example, the method 2b shown in Figure 2B further includes step S24, and step S25b is replaced by step S25a shown in Figure 2A. Also, steps S20 to S23 shown in Figure 2B are substantially the same as steps S20 to S23 shown in Figure 2A. Therefore, the vanadium-based material may be a vanadium-based material prepared by, for example, some steps of the method 2a in Figure 2A or the method 2b in Figure 2B, and can be obtained, for example, by step S20 or steps S20 to S21 in Figure 2A or Figure 2B, and a detailed explanation of its specific embodiment is omitted here, as it can be found by referring to the above description. The specific embodiments of the conductive agent and binder shown in step S22 of Figures 1B and 2B can be found by referring to the above description, so a detailed explanation is omitted here.

[0043] Please refer to Figure 1B. The second modified layer 13 shown in Figure 1B may contain at least one selected from PEDOT and PANI. In some embodiments, the second modified layer 13 contains at least one selected from PEDOT and its derivatives, such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS). The thickness of the second modified layer 13 may be 5 to 15 μm, for example about 10 μm, but is not limited thereto.

[0044] The specific embodiments of the separator 14, negative electrode 16, and aqueous electrolyte 18 shown in Figure 1B can be found by referring to the above description, so a detailed explanation is omitted here.

[0045] Next, please refer to Figure 2B in conjunction with Figure 1B. Figure 2B shows a method for preparing a modified cathode structure and a method 2b for preparing a zinc vanadium battery 1b including the modified cathode structure. It should be noted that before preparing a zinc vanadium battery 1b including the modified cathode structure, it is necessary to first prepare the modified cathode structure. In other words, the method for preparing the modified cathode structure can be included in the method 2b for preparing a zinc vanadium battery 1b including the modified cathode structure. For example, the method for preparing the modified cathode structure may be steps S20 to S24 of method 2b, and the method 2b for preparing a zinc vanadium battery 1b including the modified cathode structure can be completed by assembling the modified cathode structure, separator 14 and negative electrode 16 obtained through steps S20 to S24 according to step S25b, and immersing these structures in an aqueous electrolyte 18.

[0046] For more details, please refer to Figure 2B. The method 2b for preparing a zinc-vanadium battery 1b including a modified cathode structure may include steps S20-S24 and S25b.

[0047] The specific embodiments of steps S20 (first homogenization step), S21 (drying step), S22 (second homogenization step), and S23 (first coating step) shown in Figure 2B can be found by referring to the specific embodiments of steps S20 to S23 in Figure 2A, so a detailed explanation is omitted here.

[0048] Step S24, shown in Figure 2B, is a second coating step that includes coating the second modifying material onto the first modified layer 12 (Figure 1B) to form the second modified layer 13 on the first modified layer 12. For example, the second modifying material can be coated onto the second modified layer 13 using a frame-type four-sided applicator. In some embodiments, after coating the second modifying material onto the first modified layer 12, the second modifying material, the first modified layer 12, and the positive electrode 10 can be subjected to a further drying step to complete the second modified layer 13. For example, step S24 is completed by drying the second modified layer 13 on the first modified layer 12, the first modified layer 12, and the positive electrode 10 at approximately 80-100°C (e.g., approximately 100°C) for approximately one hour. Specific embodiments of the positive electrode 10, the first modified layer 12, and the second modified layer 13 can be found in the previously described content, so a detailed explanation is omitted here.

[0049] After completing step S24 in Figure 2B, the first modified layer 12 and the second modified layer 13 on the obtained positive electrode 10 can be used as the modified positive electrode structure described above. In some embodiments, the obtained modified positive electrode structure can be further subjected to step S25b according to Figure 2B to obtain a zinc-vanadium battery 1b.

[0050] Please refer to Figure 2B. Step S25b is an assembly step that includes assembling the separator 14 and the negative electrode 16 sequentially on the second modified layer 13, and immersing the positive electrode 10, the first modified layer 12, the second modified layer 13, the separator 14, and the negative electrode 16 in an aqueous electrolyte 18 (Figure 1B) to obtain a zinc vanadium battery 1b. For example, after assembling the modified positive electrode structure (including the positive electrode 10, the first modified layer 12, and the second modified layer 13), the separator 14, and the negative electrode 16 sequentially, the final zinc vanadium battery 1b can be obtained by sealing it with a hydraulic press in accordance with the specifications for a CR2032 button cell battery. Specific embodiments of the positive electrode 10, the first modified layer 12, the second modified layer 13, the separator 14, the negative electrode 16, and the aqueous electrolyte 18 can be found in the previously described content, so a detailed explanation is omitted here. In some embodiments, the thickness of the positive electrode 10 is approximately 5 to 50 μm, the thickness of the first modified layer 12 is approximately 70 to 90 μm, the thickness of the second modified layer 13 is approximately 5 to 15 μm, the thickness of the separator 14 is approximately 30 to 400 μm, and the thickness of the negative electrode 16 is approximately 10 to 50 μm.

[0051] The following shows the X-ray diffraction patterns of Comparative Example 1 and Examples 1-2 for the modified vanadium-based material I8 / I 20 Explain.

[0052] (Comparative Example 1: Unmodified vanadium-based material (I8 / I 20 =0)) Material selection: Vanadium oxide (V2O5). Specifications of the vanadium oxide used in this comparative example: CAS No. 1314-62-1, average particle size 50 μm, purity > 99%. This vanadium oxide has a peak at 2θ = 20° ± 1.0°, but no peak corresponding to 2θ = 8° ± 1.0° (i.e., I8 = 0), indicating that I8 / I 20 = 0.

[0053] (XRD measurement results: Unmodified vanadium-based material used in Comparative Example 1) Referring to Figure 3A, Figure 3A shows the X-ray diffraction pattern of Comparative Example 1 (known to the present inventors) of a vanadium-based material measured by XRD using CuKα1 rays. As can be seen from the XRD measurement results in Figure 3A, when vanadium oxide (V2O5) is not modified with hydrogen peroxide and water, this vanadium-based material does not show a peak corresponding to the position 2θ = 8° ± 1.0° (i.e., I8 = 0), and therefore I8 / I 20 = 0.

[0054] (Example 1: Modified vanadium-based material (I8 / I 20 =1.13)) Material selection: The solution contained vanadium oxide (V2O5), water, and hydrogen peroxide, in weight proportions of 35 parts by weight, 600 parts by weight, and 10 parts by weight, respectively. Specifications of the vanadium oxide used in this example: CAS No. 1314-62-1, average particle size 50 μm, purity >99%. This vanadium oxide exhibits a peak at 2θ = 20° ± 1.0°, but does not exhibit a peak corresponding to 2θ = 8° ± 1.0° (i.e., I8 = 0), indicating I8 / I 20 = 0.

[0055] [Manufacturing method] (1) Mix 35 parts by weight of vanadium oxide (V2O5), 600 parts by weight of water, and 60 parts by weight of hydrogen peroxide, and homogenize to obtain a vanadium-based homogeneous mixture. (2) After freezing a vanadium-based homogeneous mixture into a frozen state, a vacuum is applied, and the mixture is heated to 40°C and maintained at that temperature for 12 hours or more (maintained for approximately 12 hours) to obtain a dry, powdered vanadium-based material.

[0056] (XRD measurement results: Modified vanadium-based material used in Example 1) Referring to Figure 3B, Figure 3B shows the X-ray diffraction pattern of the vanadium-based material of Example 1 (several embodiments of the present invention) measured by XRD using CuKα1 rays. As can be seen from the XRD measurement results in Figure 3B, the vanadium-based material used in Example 1 is a vanadium-based material obtained by modifying vanadium oxide (V2O5) with hydrogen peroxide and water, and therefore the peak corresponding to the position 2θ = 20° ± 1.0° (I 20 In addition to the possibility of the following appearing, a peak (I8) also appears at the position 2θ = 8° ± 1.0°, and I8 / I 20 = 1.13 was calculated.

[0057] (Example 2: Modified vanadium-based material (I8 / I 20 =1.35)) Selection of materials: Since the materials are the same as in Example 1 described above, please refer to the description of Example 1, and a detailed explanation will be omitted here.

[0058] Manufacturing method: Since it is the same as in Example 1 described above, please refer to the description of Example 1, and a detailed explanation will be omitted here.

[0059] (XRD measurement results: Modified vanadium-based material used in Example 2) Referring to Figure 3C, Figure 3C shows the X-ray diffraction pattern of the vanadium-based material of Example 2 (another embodiment of the present invention) measured by XRD using CuKα1 rays. As can be seen from the XRD measurement results in Figure 3C, similar to Example 1, the vanadium-based material used in Example 2 is a vanadium-based material obtained by modifying vanadium oxide (V2O5) with hydrogen peroxide and water, and therefore the peak corresponding to the position 2θ = 20° ± 1.0° (I 20 In addition to the possibility of the following appearing, a peak (I8) also appears at the position 2θ = 8° ± 1.0°, and I8 / I 20 = 1.35 was calculated.

[0060] When the XRD measurement results of Comparative Example 1 and Examples 1-2 described above are combined, only the X-ray diffraction patterns of Examples 1-2 (vanadium-based materials are vanadium-based materials obtained by modifying vanadium oxide (V2O5) with at least hydrogen peroxide and water) show simultaneous peaks at positions 2θ=8°±1.0° and 2θ=20°±1.0°, and the two resulting peaks are 0 <I8 / I 20 The peak intensity relationship ≤ 1.4 is satisfied, and 1.1 ≤ I8 / I 20 It can be seen that the peak intensity relationship of ≤1.4 is also satisfied.

[0061] The preparation methods for Comparative Example 2 and Examples 3-7 will be described below. Comparative Example 2 is a zinc vanadium battery (I8 / I8) known to the inventors of the present invention. 20 Examples 3-7 are zinc vanadium batteries 1a, 1b (I8 / I8) of several embodiments of the present invention. 20 (The first modified layer 12, which contained a vanadium-based material with a ratio of 1.35, was used), and further comparisons were made as shown in Table 1 below.

[0062] [Table 1]

[0063] The preparation methods for Comparative Example 2 and Example 8 will be described below. Comparative Example 2 is a zinc vanadium battery (I8 / I) known to the inventors of the present invention. 20 Example 8 is a zinc vanadium battery 1a (I8 / I) containing a vanadium-based material with a ratio of 1.35. 20 (The first modified layer 12, which contained vanadium-based material with a value of 1.13, was used), and further comparisons were made as shown in Table 2 below.

[0064] [Table 2]

[0065] (Comparative Example 2: Zinc-vanadium battery with titanium foil as the positive electrode) [Selection of materials] (1) Positive electrode: Contains titanium foil and has a thickness of approximately 50 μm. (2) Vanadium-based homogeneous mixture: containing vanadium oxide (V2O5), water, and hydrogen peroxide, in weight proportions of 35 parts by weight, 600 parts by weight, and 10 parts by weight, respectively. Specification of the vanadium oxide used in this comparative example: CAS No. 1314-62-1, average particle size 50 μm, purity > 99%. This vanadium oxide has a peak at the position 2θ = 20° ± 1.0°, but the peak corresponding to the position 2θ = 8° ± 1.0° (i.e., I8 = 0) does not appear, indicating I8 / I 20 = 0, (3) Modified layer: Contains vanadium-based material (obtained by drying the above-mentioned vanadium-based homogeneous mixture), conductive agent (conductive carbon black), binder (PVDF), and organic solvent (NMP), with a thickness of approximately 88 μm. (4) Separator: Contains glass fibers and has a thickness of approximately 350 μm. (5) Negative electrode: Contains zinc foil and has a thickness of approximately 50 μm. (6) Aqueous electrolyte: Contains water and 2M Zn(OTf)2, with weight percentages of 57.72 parts by weight and 42.28 parts by weight, respectively.

[0066] [Manufacturing method] (1) Mix 35 parts by weight of vanadium oxide (V2O5), 600 parts by weight of water, and 60 parts by weight of hydrogen peroxide, and homogenize to obtain a vanadium-based homogeneous mixture. (2) After freezing a vanadium-based homogeneous mixture into a frozen state, a vacuum was applied, and the mixture was heated to 40°C and maintained at that temperature for 12 hours or more (in this comparative example, it was maintained for approximately 12 hours) to obtain a dry, powdery vanadium-based material. The XRD measurement results of the vanadium-based material were the same as the X-ray diffraction pattern shown in Example 2, i.e., I8 / I 20 Refer to =1.35, (3) Mix 80 parts by weight of vanadium-based material, 10 parts by weight of conductive agent, and 10 parts by weight of binder in an organic solvent and homogenize to obtain a modified material (without obvious aggregated particles and with a particle size of less than 60 μm). (4) The modified material is applied onto the titanium foil serving as the positive electrode using a frame-type four-sided applicator, and the positive electrode and modified material are dried at 100°C for 1 hour to obtain a modified layer. (5) After assembling the positive electrode, reforming layer, separator and negative electrode, immerse them in an aqueous electrolyte solution. (6) By sealing the CR2032 button cell battery with a hydraulic press according to the specifications, a zinc vanadium battery as Comparative Example 2 was obtained. (Note that the zinc-vanadium battery of Comparative Example 2 has a battery structure similar to the zinc-vanadium battery 1a shown in Figure 1A, and the main difference between the two is, for example, the selection of materials for each layer and the aqueous electrolyte.)

[0067] (Example 3: Zinc-vanadium battery 1a using carbon-coated aluminum foil as the positive electrode 10 of several embodiments of the present invention) [Selection of materials] (1) Positive electrode 10: Contains carbon-coated aluminum foil, with a thickness of approximately 20 μm, and the thickness of the carbon coating covering the aluminum foil is approximately 1 to 5 μm (in this embodiment, a carbon coating with a thickness of approximately 1.5 μm was used on the aluminum foil). (2) Vanadium-based homogeneous mixture: containing vanadium oxide (V2O5), water, and hydrogen peroxide, in weight proportions of 35 parts by weight, 600 parts by weight, and 10 parts by weight, respectively. Specifications of the vanadium oxide used in this example: CAS No. 1314-62-1, average particle size 50 μm, purity >99%. This vanadium oxide has a peak at 2θ = 20° ± 1.0°, but no peak corresponding to 2θ = 8° ± 1.0° (i.e., I8 = 0), indicating I8 / I 20 = 0, (3) First modified layer 12: Contains a vanadium-based material (obtained by drying the above-mentioned vanadium-based homogeneous mixture), a conductive agent (conductive carbon black), a binder (PVDF), and an organic solvent (NMP), and has a thickness of approximately 88 μm. (4) Separator 14: Contains cellulose and has a thickness of approximately 50 μm. (5) Negative electrode 16: Contains zinc foil and has a thickness of approximately 50 μm. (6) Aqueous electrolyte 18: Contains water and 0.5 to 3 M ZnSO4 (2 M ZnSO4 was used in this example), with weight percentages of 57.72 parts by weight and 42.28 parts by weight, respectively.

[0068] [Manufacturing method] (1) Mix 35 parts by weight of vanadium oxide (V2O5), 600 parts by weight of water, and 60 parts by weight of hydrogen peroxide, and homogenize to obtain a vanadium-based homogeneous mixture. (2) After freezing a vanadium-based homogeneous mixture into a frozen state, a vacuum is applied and it is heated to 40°C and the temperature is maintained for 12 hours or more (in this example, it was maintained for about 12 hours) to obtain a dry, powdery vanadium-based material. The XRD measurement results of the vanadium-based material show the X-ray diffraction pattern shown in Example 2, i.e., I8 / I 20 Refer to =1.35, (3) Mix 80 parts by weight of vanadium-based material, 10 parts by weight of conductive agent, and 10 parts by weight of binder in an organic solvent and homogenize to obtain a first modified material (without obvious aggregated particles and with a particle size of less than 60 μm). (4) The first modified material is applied to the carbon-coated aluminum foil serving as the positive electrode using a frame-type four-sided applicator, and the positive electrode 10 and the first modified material are dried at 100°C for 1 hour to obtain the first modified layer 12. (5) After assembling the positive electrode 10, the first reforming layer 12, the separator 14, and the negative electrode 16, they are immersed in the aqueous electrolyte 18. (6) By sealing the battery with a hydraulic press in accordance with the specifications for a CR2032 button cell, a zinc vanadium battery 1a as Example 3 was obtained.

[0069] (Example 4: Zinc-vanadium battery 1a using carbon-coated aluminum foil as the positive electrode 10 of several embodiments of the present invention) [Selection of materials] (1) Positive electrode 10, vanadium-based homogeneous mixture, first reforming layer 12, and negative electrode 16: These are the same as in Example 3 described above, so please refer to the description in Example 3. A detailed explanation will be omitted here. (2) Separator 14: Contains glass fiber and has a thickness of approximately 350 μm. (3) Aqueous electrolyte 18: Contains water, 1-5 M Zn(OTf)2 (in this example, 2 M Zn(OTf)2 was used), and 0.1-1 M LiN(CF3SO2)2 (in this example, 0.125 M LiN(CF3SO2)2 was used), with weight proportions of 57.72 parts by weight, 42.28 parts by weight, and 1.98 parts by weight, respectively.

[0070] Manufacturing method: Since it is the same as in Example 3 described above, you can refer to the description of Example 3 above, and a detailed explanation is omitted here, and a zinc vanadium battery 1a as Example 4 is obtained.

[0071] (Example 5: Zinc-vanadium battery 1b using carbon-coated aluminum foil as the positive electrode 10 of several embodiments of the present invention) [Selection of materials] (1) Positive electrode 10, vanadium-based homogeneous mixture, first reforming layer 12, separator 14, negative electrode 16, and aqueous electrolyte 18: These are the same as in Example 3 described above, so please refer to the description of Example 3, and a detailed explanation will be omitted here. (2) Second modified layer 13: Contains PEDOT and has a thickness of approximately 10 μm.

[0072] [Manufacturing method] (1) Mix 35 parts by weight of vanadium oxide (V2O5), 600 parts by weight of water, and 60 parts by weight of hydrogen peroxide, and homogenize to obtain a vanadium-based homogeneous mixture. (2) After freezing a vanadium-based homogeneous mixture into a frozen state, a vacuum is applied and it is heated to 40°C and the temperature is maintained for 12 hours or more (in this example, it was maintained for about 12 hours) to obtain a dry, powdery vanadium-based material. The XRD measurement results of the vanadium-based material show the X-ray diffraction pattern shown in Example 2, i.e., I8 / I 20 Refer to =1.35, (3) Mix 80 parts by weight of vanadium-based material, 10 parts by weight of conductive agent, and 10 parts by weight of binder in an organic solvent and homogenize to obtain a first modified material (without obvious aggregated particles and with a particle size of less than 60 μm). (4) The first modified material is applied to the carbon-coated aluminum foil serving as the positive electrode using a frame-type four-sided applicator, and the positive electrode 10 and the first modified material are dried at 100°C for 1 hour to obtain the first modified layer 12. (5) The second modified material is applied onto the first modified layer 12 using a frame-type four-sided applicator, and the positive electrode 10, the first modified layer 12, and the second modified material are dried at 100°C for 1 hour to obtain the second modified layer 13. (6) After assembling the positive electrode 10, the first reformed layer 12, the second reformed layer 13, the separator 14, and the negative electrode 16, they are immersed in the aqueous electrolyte 18. (7) By sealing it with a hydraulic press in accordance with the specifications for CR2032 button batteries, a zinc vanadium battery 1b as Example 5 was obtained.

[0073] (Example 6: Zinc-vanadium battery 1b using carbon-coated aluminum foil as the positive electrode 10 of several embodiments of the present invention) [Selection of materials] (1) Positive electrode 10, vanadium-based homogeneous mixture, first reformed layer 12, second reformed layer 13, separator 14 and negative electrode 16: These are the same as in Example 3 described above, so please refer to the description of Example 3, and a detailed explanation will be omitted here. (2) Aqueous electrolyte 18: Contains water, 1-5 M ZnSO4 (in this example, 2 M ZnSO4 was used), and 0.1-0.3 M (NH4)2SO4 (in this example, 0.25 M (NH4)2SO4 was used), with weight proportions of 57.72 parts by weight, 42.28 parts by weight, and 2.05 parts by weight, respectively.

[0074] Manufacturing method: Since it is the same as in Example 5 described above, you can refer to the description of Example 5 above, and a detailed explanation is omitted here, and a zinc vanadium battery 1b as Example 6 is obtained.

[0075] (Example 7: Zinc-vanadium battery 1b using carbon-coated aluminum foil as the positive electrode 10 of several embodiments of the present invention) Material selection: Since it is the same as in Example 5 described above, you can refer to the description of Example 5 above, and a detailed explanation will be omitted here.

[0076] Manufacturing method: The method is almost the same as in Example 5 described above, but the main difference is that, for example, the positive electrode 10, the first modified layer 12, the second modified layer 13, the separator 14, and the negative electrode 16 are assembled, immersed in an aqueous electrolyte 18, and then sealed in a soft pack type battery to obtain the zinc vanadium battery 1b as Example 7.

[0077] The discharge capacity and average lifespan of the batteries in Comparative Example 2 and Examples 3-8 will be explained below through Experimental Examples 1-2.

[0078] (Experimental Example 1: Battery Discharge Capacity) [Test Method] The battery test method used in this experiment was a constant current charge-discharge test. Each battery under test was discharged via a charge-discharge device at a pre-set constant current (usually called current density, which can be set to 100 mA / g or 200 mA / g using the weight of the electrode reactants as a reference value (in this experiment, the current density was set to 200 mA / g)), and the discharge time and total discharge capacity were recorded. Furthermore, dividing the product of this time and total discharge capacity by the weight of the positive electrode yields the capacity per gram of battery in milliampere-hours per gram (mAh / g).

[0079] [Test Results] Referring to Table 3 and Figure 4 below, Figure 4 is a comparison chart of the discharge capacities of the zinc-vanadium battery of Comparative Example 2 (using zinc foil for the positive electrode) and the zinc-vanadium batteries 1a and 1b of Examples 3-8 (using carbon-coated aluminum foil for the positive electrode). As can be seen from the discharge capacity test results of the batteries in Table 3 and Figure 4, the average discharge capacities of the batteries of Examples 3-6, sealed in button cell bodies, were approximately 217, 213, 175, and 295 mAh / g, respectively. Compared to the average discharge capacity of the battery of Comparative Example 2 (approximately 127 mAh / g), the average discharge capacities of the batteries of Examples 3-6 increased by approximately 70.9%, 67.7%, 37.8%, and 132.3%, respectively. In other words, in the zinc-vanadium batteries 1a and 1b of Examples 3 to 6, carbon-coated aluminum foil was used for the positive electrode 10, the first modified layer 12 in both cases contained a modified vanadium-based material, and by using different combinations of the second modified layer 13 and the aqueous electrolyte 18, the average discharge capacity of the battery could be significantly improved.

[0080] [Table 3]

[0081] As can be seen from the battery discharge capacity test results in Table 3 and Figure 4, the average discharge capacity of the battery in Example 7, which was sealed in a soft pack type battery, reached 203 mAh / g. Compared to the average discharge capacity of the battery in Comparative Example 2 (approximately 127 mAh / g), the average discharge capacity of the battery in Example 7 increased by approximately 59.8%. In other words, even though the zinc-vanadium battery 1b of Example 7 was sealed in a soft pack type battery, the use of carbon-coated aluminum foil for the positive electrode 10 of the zinc-vanadium battery 1b, the inclusion of a modified vanadium-based material in both the first modified layer 12 and the combination of the second modified layer 13 and the aqueous electrolyte 18 significantly improved the average discharge capacity of the battery.

[0082] Furthermore, compared to Example 5, which was sealed in a button cell (also equipped with a second modified layer 13 and using the same aqueous electrolyte 18, with a discharge capacity of approximately 175 mAh / g), the zinc-vanadium battery 1b of Example 7, even when sealed in a soft pack type battery, was able to increase the average discharge capacity of the battery by approximately 16.0%, demonstrating superior average discharge capacity.

[0083] Furthermore, as can be seen from the battery discharge capacity test results in Table 3 and Figure 4, Example 3 (I8 / I) sealed in a button cell 20 Example 8 (I8 / I) uses a first modified layer 12 containing vanadium-based material with a ratio of 1.35. 20 The average discharge capacities of the batteries (using the first modified layer 12 containing a vanadium-based material with a ratio of 1.13) were approximately 217 and 258 mAh / g, respectively. Compared to the average discharge capacity of the battery in Comparative Example 2 (approximately 127 mAh / g), the average discharge capacities of the batteries in Example 3 and Example 8 increased by approximately 70.9% and 103.1%, respectively. In other words, the positive electrode 10 of the zinc-vanadium batteries 1a in Example 3 and Example 8 both used carbon-coated aluminum foil, and the first modified layer 12 in both cases was I8 / I8. 20 The invention includes vanadium-based materials modified to 1.35 and 1.13, and further, when used in combination with the corresponding second modified layer 13 and aqueous electrolyte 18, the average discharge capacity of the battery could be significantly improved. Therefore, in some embodiments, I8 / I 20 is at least 1.13 to 1.35 (i.e., 1.1 ≤ I8 / I) 20 A zinc-vanadium battery 1a containing vanadium-based material ≤1.4) was able to reliably achieve a significantly improved average discharge capacity.

[0084] (Experimental Example 2: Average Battery Life) [Test Method] In this experiment, the battery's operating voltage range was set to 0.2~2.0V (the battery's operating voltage in this experiment was set to 2.0V) via a charge / discharge device (purchased from Xinke Power Technology Co., Ltd.), and the batteries of Comparative Example 2 and Examples 3-7 were continuously charged at least 30 times with a fixed current density of 100mA / g or 200mA / g (the current density in this experiment was set to 200mA / g) to test the average cycle life of the batteries. The battery of Example 8 was charged at least once to test its cycle life.

[0085] [Test Results] Referring to Table 4 and Figure 5 below, Figure 5 is a comparison chart of the average lifespan of the zinc-vanadium battery of Comparative Example 2 (using zinc foil for the positive electrode) and the zinc-vanadium batteries 1a and 1b of Examples 3 to 8 (using carbon-coated aluminum foil for the positive electrode). As can be seen from the average lifespan test results of the batteries in Table 4 and Figure 5, the average lifespans of the batteries in Examples 3 to 6 were approximately 75, 101, 101, and 73 cycles, respectively. Compared to the average lifespan of the battery in Comparative Example 2 (approximately 14 cycles), the average lifespans of the batteries in Examples 3 to 6 increased by approximately 435.7%, 621.4%, 621.4%, and 421.4%, respectively. The average discharge capacities of the batteries in Examples 3-6, sealed in button cell form, were approximately 217, 213, 175, and 295 mAh / g, respectively. Compared to the average discharge capacity of the battery in Comparative Example 2 (approximately 127 mAh / g), the average discharge capacities of the batteries in Examples 3-6 increased by approximately 70.9%, 67.7%, 37.8%, and 132.3%, respectively. In other words, by using carbon-coated aluminum foil for the positive electrode 10 of the zinc-vanadium batteries 1a and 1b in Examples 3-6, and by using different combinations of the first modified layer 12 containing a modified vanadium-based material, as well as different combinations of the second modified layer 13 and the aqueous electrolyte 18, the average lifespan of the batteries was also significantly improved.

[0086] [Table 4]

[0087] As can be seen from the average battery life test results in Table 4 and Figure 5, the average life of the battery in Example 7, which was sealed in a soft pack type battery, was 15 cycles, which is a 7.1% increase compared to the average life of the battery in Comparative Example 2 (approximately 14 cycles). In other words, even though the zinc-vanadium battery 1b of Example 7 was sealed in a soft pack type battery, the average life of the battery could be significantly improved by using carbon-coated aluminum foil for the positive electrode 10 of the zinc-vanadium battery 1b, by including a modified vanadium-based material in both the first modified layer 12 and the combination of the second modified layer 13 and the aqueous electrolyte 18.

[0088] Furthermore, as can be seen from the average battery life test results in Table 4 and Figure 5, Example 3 (I8 / I) sealed in a button battery 20 Example 8 (I8 / I) uses a first modified layer 12 containing vanadium-based material with a ratio of 1.35. 20 The average lifespan of the batteries in Example 3 and Example 8 (using the first modified layer 12 containing a vanadium-based material with a ratio of 1.13) was approximately 75 and 51 cycles, respectively. Compared to the average lifespan of the battery in Comparative Example 2 (approximately 14 cycles), the average lifespans of the batteries in Example 3 and Example 8 increased by approximately 435.7% and 264.3%, respectively. In other words, the positive electrode 10 of the zinc-vanadium batteries 1a in Example 3 and Example 8 both used carbon-coated aluminum foil, and the first modified layer 12 in both was I8 / I 20 The invention includes vanadium-based materials modified to 1.35 and 1.13, and further, when used in combination with the corresponding second modified layer 13 and aqueous electrolyte 18, the average lifespan of the battery could be significantly improved. Therefore, in some embodiments, I8 / I 20 is at least 1.13 to 1.35 (i.e., 1.1 ≤ I8 / I) 20 A zinc-vanadium battery 1a containing vanadium-based material with a value of ≤1.4) was able to reliably achieve a significantly improved average battery life.

[0089] In short, in some embodiments, the modified cathode structure includes a vanadium-based material obtained by modifying vanadium oxide with hydrogen peroxide and water. Compared to conventional zinc-vanadium batteries that do not include this modified vanadium-based material, in some embodiments, the modified cathode structure (i.e., including a first modified layer containing the modified vanadium-based material, or further including a second modified layer) can be used in combination with different combinations of a carbon-coated aluminum foil cathode, the second modified layer, and an aqueous electrolyte, thereby significantly improving the average discharge capacity and average lifespan of the battery. Since the above modified cathode structure is used as the cathode of a zinc-vanadium battery, the solutions provided in some embodiments differ from currently common methods for preparing aqueous electrolytes, yet they were still able to produce the effect of significantly improving the average discharge capacity and average lifespan of the battery.

[0090] While examples have been disclosed in this invention as described above, these are by no means limiting to the present invention. Anyone familiar with the art may make various modifications and embellishments without departing from the spirit and scope of the invention. Therefore, the scope of protection of this invention shall be based on the claims attached herein. [Explanation of symbols]

[0091] 10 positive electrode 1a, 1b Zinc-vanadium battery 12. First Modified Layer 13. Second Modified Layer 14 Separator 16 negative electrode 18 Aqueous electrolyte 2a, 2b (Preparation of zinc-vanadium batteries including a modified cathode structure) S20~S24,S25a,S25b process

Claims

1. A positive electrode containing aluminum covered with a carbon coating, Located on the positive electrode, Vanadium-based material 70 to 95 parts by weight, 3 to 45 parts by weight of conductive agent, and Binder 3-45 weight units A modified cathode structure comprising a first modified layer containing, In the X-ray diffraction pattern of vanadium-based materials measured by an X-ray diffractometer (XRD) using CuKα1 rays, the peak intensity at 2θ = 8° ± 1.0° is I ８ The peak intensity at 2θ = 20° ± 1.0° is I ２０ In that case, the above I ８ and the aforementioned I ２０ Ratio to (I ８ / I ２０ ) is 0 < I ８ / I ２０ A modified cathode structure that satisfies ≤ 1.

4.

2. The modified cathode structure according to claim 1, further comprising a second modified layer located on the first modified layer and comprising at least one selected from poly(3,4-ethylenedioxythiophene), PEDOT and polyaniline, PANI.

3. The aforementioned I ８ and the aforementioned I ２０ The ratio (I ８ / I ２０ ) satisfies 1.1 ≤ I ８ / I ２０ ≤ 1.

4. The modified positive electrode structure according to claim 1 or claim 2

4. The modified cathode structure according to claim 1 or claim 2, wherein the conductive agent contains at least one of conductive carbon black and carbon nanotubes.

5. The modified cathode structure according to claim 1 or claim 2, wherein the binder contains at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), and polyimide.

6. A first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture, A drying step comprising freeze-drying or heat-drying the aforementioned vanadium-based homogeneous mixture to obtain the vanadium-based material, A second homogenization step includes mixing the vanadium-based material, the conductive agent, and the binder to homogenize them and obtain a first modified material, A method for preparing a modified cathode structure according to claim 1, comprising a coating step of coating the first modified material onto the cathode to form the first modified layer on the cathode.

7. The first homogenization step includes homogenizing the vanadium oxide, water, and hydrogen peroxide in a weight ratio of 7:120:2 to 12 at room temperature and atmospheric pressure to obtain the vanadium-based homogeneous mixture. The preparation method according to claim 6, wherein the second homogenization step includes homogenizing the vanadium-based material, the conductive agent, and the binder in a weight ratio of 70 to 95:3 to 45:3 to 45 under normal temperature and pressure to obtain the first modified material.

8. A first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture, A drying step comprising freeze-drying or heat-drying the aforementioned vanadium-based homogeneous mixture to obtain the vanadium-based material, A second homogenization step includes mixing the vanadium-based material, the conductive agent, and the binder to homogenize them and obtain a first modified material, A first coating step includes applying the first modifying material onto the positive electrode to form the first modifying layer on the positive electrode. A method for preparing a modified cathode structure according to claim 2, comprising a second coating step of coating the first modified layer with a second modified material containing at least one of PEDOT and PANI to form the second modified layer on the first modified layer.

9. The first homogenization step includes homogenizing the vanadium oxide, water, and hydrogen peroxide in a weight ratio of 7:120:2 to 12 at room temperature and atmospheric pressure to obtain the vanadium-based homogeneous mixture. The method for preparing a modified cathode structure according to claim 8, wherein the second homogenization step includes homogenizing the vanadium-based material, the conductive agent, and the binder in a weight ratio of 70 to 95:3 to 45:3 to 45 under normal temperature and pressure to obtain the first modified material.

10. A positive electrode containing aluminum covered with a carbon coating, Located on the positive electrode, Vanadium-based material 70 to 95 parts by weight, 3 to 45 parts by weight of conductive agent, and Binder 3-45 weight units A first modified layer containing A separator located on the first modified layer, A negative electrode containing zinc and located on the separator, A zinc-vanadium battery comprising an aqueous electrolyte containing the positive electrode, the first modified layer, the separator, and the negative electrode inside, In the X-ray diffraction pattern of vanadium-based materials measured by an X-ray diffractometer (XRD) using CuKα1 rays, the peak intensity at 2θ = 8° ± 1.0° is I ８ The peak intensity at 2θ = 20° ± 1.0° is I ２０ In that case, the above I ８ and the aforementioned I ２０ Ratio to (I ８ / I ２０ ) is 0 < I ８ / I ２０ A zinc-vanadium battery that satisfies ≤ 1.

4.

11. The zinc vanadium battery according to claim 10, further comprising a second modified layer located on the first modified layer and comprising at least one selected from poly(3,4-ethylenedioxythiophene), PEDOT and polyaniline, wherein the separator is located on the second modified layer and the positive electrode, the first modified layer, the second modified layer, the separator and the negative electrode are in the aqueous electrolyte.

12. The above I ８ and the aforementioned I ２０ Ratio to (I ８ / I ２０ ) but 1.1 ≤ I ８ / I ２０ A zinc-vanadium battery according to claim 10 or claim 11, satisfying ≤ 1.

4.

13. The aforementioned aqueous electrolyte is zinc sulfate (ZnSO4). ４ ) and zinc triflate (Zn(OTf)) ２ The zinc vanadium battery according to claim 10 or claim 11, which is an aqueous solution containing at least one of the following:

14. The aforementioned aqueous electrolyte consists of water, zinc triflate (Zn(OTf)) ２ ) and lithium bis(trifluoromethanesulfonyl)imide (LiN(CF ３ SO ２ ) ２ A zinc vanadium battery according to claim 10 or claim 11, which is an aqueous solution containing ).

15. The water, the Zn(OTf) ２ and the LiN(CF ３ SO ２ ) ２ The zinc vanadium battery according to claim 14, wherein the weight ratio is 1.4:1:0.01 to 0.

28.

16. The aforementioned aqueous electrolyte consists of water, zinc sulfate (ZnSO4). ４ ) and ammonium sulfate ((NH ４ ) ２ SO ４ The zinc vanadium battery according to claim 11, which is an aqueous solution containing ).

17. The water, The ZnSO ４ and the above (NH ４ ) ２ SO ４ The zinc vanadium battery according to claim 16, wherein the weight ratio is 1.4:1:0.02 to 0.

17.

18. The zinc vanadium battery according to claim 10 or claim 11, wherein the conductive agent contains at least one of conductive carbon black and carbon nanotubes.

19. The zinc vanadium battery according to claim 10 or claim 11, wherein the binder contains at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), and polyimide.

20. The zinc vanadium battery according to claim 10 or claim 11, wherein the separator contains cellulose or glass fiber.

21. A first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture, A drying step comprising freeze-drying or heat-drying the aforementioned vanadium-based homogeneous mixture to obtain the vanadium-based material, A second homogenization step includes mixing the vanadium-based material, the conductive agent, and the binder to homogenize them and obtain a first modified material, A coating step including applying the first modifying material onto the positive electrode to form the first modifying layer on the positive electrode. A method for preparing a zinc-vanadium battery according to claim 10, comprising an assembly step of sequentially assembling the separator and the negative electrode on the first modified layer, and immersing the positive electrode, the first modified layer, the separator and the negative electrode in the aqueous electrolyte to obtain the zinc-vanadium battery.

22. The first homogenization step includes homogenizing the vanadium oxide, water, and hydrogen peroxide in a weight ratio of 7:120:2 to 12 at room temperature and atmospheric pressure to obtain the vanadium-based homogeneous mixture. The preparation method according to claim 21, wherein the second homogenization step includes homogenizing the vanadium-based material, the conductive agent, and the binder in a weight ratio of 70 to 95:3 to 45:3 to 45 under normal temperature and pressure to obtain the first modified material.

23. A first homogenization step includes mixing vanadium oxide, water, and hydrogen peroxide and homogenizing them to obtain a vanadium-based homogeneous mixture, A drying step comprising freeze-drying or heat-drying the aforementioned vanadium-based homogeneous mixture to obtain the vanadium-based material, A second homogenization step includes mixing the vanadium-based material, the conductive agent, and the binder to homogenize them and obtain a first modified material, A first coating step includes applying the first modifying material onto the positive electrode to form the first modifying layer on the positive electrode, A second coating step includes applying a second modifying material, which includes at least one selected from PEDOT and PANI, onto the first modifying layer to form the second modifying layer on the first modifying layer, A method for preparing a zinc vanadium battery according to claim 11, comprising an assembly step of sequentially assembling the separator and the negative electrode on the second modified layer, and immersing the positive electrode, the first modified layer, the second modified layer, the separator and the negative electrode in the aqueous electrolyte to obtain the zinc vanadium battery.

24. The first homogenization step includes homogenizing the vanadium oxide, water, and hydrogen peroxide in a weight ratio of 7:120:2 to 12 at room temperature and atmospheric pressure to obtain the vanadium-based homogeneous mixture. The preparation method according to claim 23, wherein the second homogenization step includes homogenizing the vanadium-based material, the conductive agent, and the binder in a weight ratio of 70 to 95:3 to 45:3 to 45 under normal temperature and pressure to obtain the first modified material.

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