Electrode plate, preparation method thereof and rust battery

Abstract

The invention discloses an electrode pole piece, a preparation method thereof and a rust battery, the electrode pole piece proposes that energy is firstly stored and then released based on reversible reaction between rust and iron, a novel energy storage mechanism capable of charging and discharging circulation is constructed, and the electrode pole piece has quick response capability and active scheduling capability, is suitable for field deployment with sudden requirements, and has high reliability and high reliability. A multi-layer current collector structure which is suitable for iron rust active components and has aperture gradient and an active substance layer are further provided to form an interlayer structure, and the active substance layer is sandwiched between two layers of current collectors with opposite small holes to serve as a basic structure unit. A current collector with relatively large holes is used as another structural unit with auxiliary supporting, gas guiding, electric conduction and other functions, and a plurality of groups of units are stacked at intervals, so that the structure of the electrode plate is stable, permeation of electrolyte is facilitated, and the service life of the electrode plate is prolonged. And the problem that in the charging process of a traditional iron-air battery, negative electrode hydrogen evolution gas is difficult to escape and battery capacity exertion is hindered can be solved.

Description

Technical Field

[0001] This invention relates to the field of air batteries, specifically to an electrode sheet and its preparation method, and a rust battery. Background Technology

[0002] With the rapid development of the new energy industry, higher requirements have been put forward for the development of efficient, safe and low-cost long-term energy storage systems. Iron-air batteries have a high specific capacity, and compared with lithium metal or zinc-based batteries, iron-air batteries are less likely to have dendrites that puncture the separator during charging and discharging, and have the potential for sustainable long-term energy storage. In addition, iron resources are abundant, the extraction technology is relatively simple and the cost is low, which is conducive to large-scale application. However, in the process of use, the current iron-air batteries still have the following problems: (1) After assembly, factory pretreatment is required, such as discharge treatment before charging, which is not conducive to on-site deployment for sudden demand; (2) The active material is easy to fall off the current collector during cycling, or the current collector and the active material are easy to lose electrical contact during cycling, resulting in serious capacity decay; (3) The current collector has limited capacity to load active material, which is not suitable for thick electrodes, and the corresponding single cell capacity is low; in particular, (4) practical research has found that even if the active material is made thicker, the battery capacity is not significantly improved and the capacity is not well utilized.

[0003] It should be noted that the information disclosed in the background section above is only for understanding the background of this application. Therefore, the background section of this invention may include background information about the problems or environment of this invention, and is not necessarily a description of the prior art. Thus, the content included in the background section does not constitute an admission of the prior art by the applicant. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a new electrode sheet with superior performance.

[0005] The present invention also provides a negative electrode containing the above-mentioned electrode plates and a rust battery, as well as the application of the rust battery in energy storage.

[0006] Based on this, the first aspect of the present invention is to provide a technical solution: an electrode sheet, the electrode sheet comprising a first unit and a second unit stacked on top of each other, the first unit comprising a first current collector having a first hole, the second unit comprising a second current collector, an active material layer and a third current collector stacked on top of each other, the second current collector having a second hole, the third current collector having a third hole, the diameter of the second hole and the diameter of the third hole being smaller than the diameter of the first hole, and the active material layer comprising ferric oxide.

[0007] In some embodiments of the present invention, the first unit has m units arranged sequentially, where m is greater than or equal to 2, and a second unit is disposed between any two adjacent first units.

[0008] According to one specific aspect of the present invention, a second unit is disposed between any two adjacent first units.

[0009] According to some preferred and specific aspects of the invention, the second unit has n units, where m = n + 1.

[0010] In some embodiments of the present invention, the second unit is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0011] In some embodiments of the present invention, each of the first units and each of the second units are stacked sequentially in the same direction.

[0012] In some embodiments of the present invention, a receiving cavity communicating with the outside is formed between the first current collector and the second current collector and / or between the first current collector and the third current collector, the receiving cavity having an opening toward the active material layer.

[0013] In some embodiments of the present invention, the first current collector is further provided with a fluid channel communicating with the first hole, and the fluid channel can also communicate with a second hole on the corresponding second current collector or a third hole on the corresponding third current collector.

[0014] Furthermore, the fluid channel has multiple channels, some or all of which extend to the edge of the first fluid collector and are able to communicate with the outside.

[0015] Furthermore, the fluid channels are multiple and at least partially interconnected. According to some specific aspects of the invention, all of the multiple fluid channels are interconnected.

[0016] According to some preferred and specific aspects of the present invention, fluid channels are formed on both opposite sides of the first current collector, and at least one of the opposite sides faces the active material layer.

[0017] In some embodiments of the present invention, the ratio of the depth of the fluid channel along the thickness direction of the first collector to the width of the fluid channel is 1:0.5-12.

[0018] In some embodiments of the present invention, the depth of the fluid channel along the thickness direction of the first collector is greater than or equal to 0.1 mm, further 0.2-3 mm, and even further 0.5-1.5 mm.

[0019] In some embodiments of the present invention, the width of the fluid channel is 2-9 mm, more specifically 3-7 mm.

[0020] In some embodiments of the present invention, the thickness of the active material layer is 100-3000 μm.

[0021] In some embodiments of the present invention, the mesh count of the second hole and the mesh count of the third hole are 100-1000 mesh, further 150-800 mesh, and even further 200-750 mesh.

[0022] In some embodiments of the present invention, the diameter of the first hole is 1-20 mm, and more specifically 4-12 mm.

[0023] In some embodiments of the present invention, the first hole has a plurality of openings, and the sum of the opening areas of each first hole accounts for 10%-70% of the corresponding opening plane area of ​​the first current collector, and may further be 10%-60%.

[0024] In some embodiments of the present invention, the thickness of the first current collector is greater than the thickness of the second current collector and the thickness of the third current collector, respectively; further, the thickness of the first current collector is 5-30 times the thickness of the second current collector, and even more so 10-20 times.

[0025] In some embodiments of the present invention, the thickness of the first current collector is 1-7 mm, more specifically 1-5 mm.

[0026] In some embodiments of the present invention, the surface of the first current collector is provided with a nickel-containing coating.

[0027] According to some preferred and specific aspects of the invention, the nickel-containing coating is a nickel-phosphorus coating. Further, the phosphorus content in the nickel-phosphorus coating is 5 wt.%-20 wt.%, and even more specifically, 8 wt.%-12 wt.%.

[0028] In some embodiments of the present invention, the thickness of the nickel-containing coating is 5-20 μm, further 6-18 μm, and even further 7-15 μm.

[0029] In some embodiments of the present invention, the materials of the first current collector, the second current collector, and the third current collector respectively include metallic conductive materials or non-metallic conductive materials.

[0030] Furthermore, the metallic conductive material includes stainless steel, nickel or its alloys, copper alloys, or aluminum alloys. In some specific cases, nickel alloys include, but are not limited to, nickel-iron alloys; copper alloys include, but are not limited to, copper-nickel alloys; and aluminum alloys include, but are not limited to, aluminum-copper and aluminum-nickel alloys.

[0031] Furthermore, the non-metallic conductive material includes conductive carbon material or conductive polymer material.

[0032] In some embodiments of the present invention, the hardness of the first current collector is greater than that of the second current collector and the third current collector, and the second current collector and the third current collector are respectively capable of bending and deformation.

[0033] According to some specific aspects of the present invention, the first current collector is a stainless steel plate with a first hole and a fluid channel, and the second current collector is a stainless steel mesh.

[0034] In some embodiments of the present invention, the electrode sheet further includes tabs formed on the first current collector; when there are multiple first current collectors, the tabs of each first current collector are connected together, and further, connected together by welding and / or fasteners.

[0035] In some embodiments of the present invention, the outer peripheral sides of the first current collector, the second current collector, and the third current collector are connected together, and further, they are connected together by welding and / or fasteners.

[0036] In some embodiments of the present invention, the second current collector is the same as the third current collector.

[0037] In some embodiments of the present invention, the second current collector and the third current collector are respectively provided with connecting portions, and the connecting portions can be connected to the first current collector.

[0038] In some embodiments of the present invention, the connecting portion is located on the side of the corresponding second current collector or the third current collector.

[0039] In some embodiments of the present invention, the length direction of the connecting portion is parallel to the length direction of the corresponding second current collector or the third current collector.

[0040] In some embodiments of the present invention, the connecting portion is connected to the first current collector spaced apart from it by the active material layer.

[0041] In some embodiments of the present invention, the width of the connecting portion extends toward the side adjacent to the active material layer.

[0042] In some embodiments of the present invention, the connecting portion on the second current collector and the connecting portion on the third current collector are located on opposite sides of the electrode plate.

[0043] In some embodiments of the present invention, the second current collector and the third current collector independently include a current collector body and the connecting portion, and the current collector body and the connecting portion are integrally formed to constitute the corresponding second current collector or the third current collector.

[0044] In some embodiments of the present invention, the active material layer comprises ferric oxide, a conductive agent, and a binder.

[0045] Furthermore, by mass percentage, the active material layer comprises 10%-30% conductive agent, 60%-80% ferric oxide, and 1%-15% binder. Even further, the conductive agent comprises a two-dimensional conductive material.

[0046] In some embodiments of the present invention, the active material layer comprises a rust electrode material, which comprises a two-dimensional conductive material, ferric oxide loaded on the two-dimensional conductive material, a zero-dimensional conductive material, and a one-dimensional conductive material; wherein the two-dimensional conductive material forms a basic framework (providing a large area for ferric oxide deposition), the zero-dimensional conductive material and the one-dimensional conductive material respectively form an epitaxial framework, and the basic framework and the epitaxial framework together constitute an interconnect framework (the interconnect structure has a confinement effect, which can restrict the aggregation and migration behavior of ferric oxide on a spatial scale), and the ferric oxide is distributed in the interconnect framework.

[0047] In some embodiments of the present invention, the active material layer comprises a rust electrode material, the rust electrode material comprising a two-dimensional conductive material, ferric oxide loaded on the two-dimensional conductive material, a zero-dimensional conductive material, and a one-dimensional conductive material;

[0048] In the rust electrode material, the two-dimensional conductive material accounts for 10%-40% by mass percentage, and the amount of the two-dimensional conductive material added is more than 1.5 times the amount of either the zero-dimensional conductive material or the one-dimensional conductive material added.

[0049] In this invention, by mixing and homogenizing ferric oxide, zero-dimensional conductive materials, one-dimensional conductive materials, and two-dimensional conductive materials, an interconnected framework can be constructed from these three materials. Ferric oxide is loaded onto the two-dimensional conductive material, which has a sheet-like structure and a large planar dimension, thus serving as a basic framework. In addition to ferric oxide, zero-dimensional and one-dimensional conductive materials can also be deposited or loaded onto the two-dimensional conductive material during the mixing process, for example, on the surface of the two-dimensional conductive material or other load-bearing parts. These zero-dimensional and one-dimensional conductive materials can act as additional epitaxial frameworks. After these epitaxial frameworks are mixed and blended together with each other and with the basic framework, a multi-scale interconnected framework can be formed.

[0050] Furthermore, the interconnected framework in this invention refers to the existence of conductive pathways in multiple dimensions, and the presence of multiple conductive pathways, thereby constructing a three-dimensional cross-linked network structure with conductive pathways in multiple spatial dimensions. This three-dimensional cross-linked network spatially confines ferric oxide, preventing its "loss" due to dissolution and redeposition during the cycling process. In addition, this interconnected framework significantly increases the deposition amount of ferric oxide in three-dimensional space, improving the loading of active materials and the feasibility of the reaction.

[0051] In some embodiments of the present invention, the ferric oxide, the zero-dimensional conductive material, and the one-dimensional conductive material are all loaded on the two-dimensional conductive material.

[0052] Furthermore, the amount of the two-dimensional conductive material added is 1.5-15 times, more specifically 1.5-12 times, and even more specifically 2-10 times, of either the zero-dimensional conductive material or the one-dimensional conductive material.

[0053] In some embodiments of the present invention, the interconnect skeleton includes multiple conductive paths, and each of the conductive paths includes the zero-dimensional conductive material, the one-dimensional conductive material, and the two-dimensional conductive material.

[0054] In some embodiments of the present invention, the zero-dimensional conductive material, the one-dimensional conductive material, and the two-dimensional conductive material are all conductive carbon materials.

[0055] In some embodiments of the present invention, the thickness of the two-dimensional conductive material is 1-300 nm, and the sheet diameter (or surface length) is 0.5-20 μm. Further, the thickness of the two-dimensional conductive material is 1-200 nm, and the sheet diameter (or surface length) is 0.5-15 μm. Even further, the thickness of the two-dimensional conductive material is 1-50 nm, and the sheet diameter (or surface length) is 1-10 μm.

[0056] In some embodiments of the present invention, the aspect ratio of the one-dimensional conductive material is 100-3000.

[0057] In some embodiments of the present invention, the particle size of the zero-dimensional conductive material is 10-500 nm.

[0058] In some embodiments of the present invention, the ferric oxide exists in the form of ferric oxide particles, the particle size of which is 10-1000 nm.

[0059] In some embodiments of the present invention, the ferric oxide accounts for 50%-75% of the rust electrode material by mass percentage.

[0060] In some embodiments of the present invention, the mass ratio of the zero-dimensional conductive material, the one-dimensional conductive material, and the two-dimensional conductive material in the rust electrode material is 1:0.1-10:1.5-40, further 1:0.2-2.8:3-15, and even further 1:0.4-2.5:3.5-9.

[0061] In some embodiments of the present invention, by mass percentage, the two-dimensional conductive material accounts for 15%-40% of the rust electrode material, the one-dimensional conductive material accounts for 1%-10%, and the zero-dimensional conductive material accounts for 1%-10%. Further, the total content of the one-dimensional conductive material and the zero-dimensional conductive material accounts for 5%-15%.

[0062] In some embodiments of the present invention, by mass percentage, the two-dimensional conductive material accounts for 18%-36% of the rust electrode material, the one-dimensional conductive material accounts for 3%-7% of the rust electrode material, and the zero-dimensional conductive material accounts for 3%-7%.

[0063] In some embodiments of the present invention, the mass ratio of the ferric oxide, the two-dimensional conductive carbon material, the one-dimensional conductive carbon material and the zero-dimensional conductive carbon material is 1:0.2-0.8:0.04-0.15:0.04-0.15.

[0064] In some embodiments of the present invention, the mass ratio of the ferric oxide, the two-dimensional conductive carbon material, the one-dimensional conductive carbon material and the zero-dimensional conductive carbon material is 1:0.25-0.75:0.05-0.15:0.04-0.12.

[0065] In some embodiments of the present invention, the two-dimensional conductive material may include, but is not limited to, graphene and / or carbon nanosheets.

[0066] In some embodiments of the present invention, the one-dimensional conductive material may include, but is not limited to, carbon nanofibers and / or carbon nanotubes. In some embodiments of the present invention, the one-dimensional conductive material may be single-walled carbon nanotubes and / or multi-walled carbon nanotubes.

[0067] In some embodiments of the present invention, the zero-dimensional conductive material may include, but is not limited to, acetylene black particles, etc.

[0068] In some embodiments of the present invention, the active material layer further comprises, by weight percentage, 1%-10% of a binder in the rust electrode material.

[0069] In some embodiments of the present invention, the adhesive may include, but is not limited to, polytetrafluoroethylene (PTFE), hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), etc., and one or more combinations thereof may be selected.

[0070] In some embodiments of the present invention, the active material layer is prepared by the following method:

[0071] The components of the active material layer are mixed and homogenized to prepare an active material mixture.

[0072] The active material mixture is pressed into an active material layer, or the active material mixture is integrally formed between the second current collector and the third current collector to form the second unit, thereby obtaining the active material layer.

[0073] Furthermore, the mixing and homogenization are carried out using a dry mixing method.

[0074] In some preferred embodiments of the present invention, during the preparation of the active material layer:

[0075] Under solvent-free conditions, ferric oxide and a two-dimensional conductive material are first mixed and stirred to obtain an intermediate. Then, a zero-dimensional conductive material and a one-dimensional conductive material are added to the intermediate, and mixing and stirring are continued. Finally, a binder is added and mixed thoroughly to prepare an active material mixture. Further, before forming the active material layer, the active material mixture is treated by rolling, grinding, or shearing to cause the binder to become fibrous.

[0076] A second aspect of the present invention is to provide another technical solution: a method for preparing the electrode sheet described above, the method comprising: pressing a first unit and a second unit stacked together together, and sealing and fixing the outer periphery of each current collector.

[0077] A third aspect of the present invention is to provide yet another technical solution: a negative electrode for an air battery, the negative electrode comprising the electrode plates described above.

[0078] A fourth aspect of the present invention is to provide yet another technical solution: a rust battery, the rust battery comprising a negative electrode, an air positive electrode and an electrolyte, wherein the negative electrode is the negative electrode for an air battery as described above.

[0079] In the "rust battery" of this invention, "rust" refers to the presence of an active material, rust (ferric oxide), in the negative electrode, and the positive electrode is the air positive electrode.

[0080] According to the present invention, the reactions of the negative and positive electrodes during the first charge are as follows:

[0081] Negative electrode reaction: Fe2O3 + 3H2O + 2e - →2Fe(OH)2+2OH - Fe(OH)2+2e - →Fe+2OH - ;

[0082] Positive electrode reaction: 4OH - →O2 + 2H2O + 4e - .

[0083] The fifth aspect of the present invention is to provide yet another technical solution: a method for using the aforementioned rust battery for energy storage, wherein the rust battery can be directly used for charging and energy storage without first discharging it.

[0084] According to some specific aspects of the present invention, during the application of the rust battery, the ferric oxide in the rust battery gains electrons and is reduced to iron during charging, and the iron loses electrons and is oxidized to iron oxide during discharging, thus achieving the initial storage and subsequent release of energy during the reduction and oxidation process.

[0085] In this invention, the terms "zero-dimensional," "one-dimensional," and "two-dimensional" in the zero-dimensional conductive material, one-dimensional conductive material, and two-dimensional conductive material mentioned herein can be understood in their usual sense, for example, as follows:

[0086] Zero-dimensional (0D) materials typically refer to materials where all three dimensions are approximately the same, with no significant aspect ratio. The dimensions in each direction are relatively similar, exhibiting a discrete granular structure. For example, the dimensions in all three dimensions are on the micrometer or nanometer scale. Typical materials include nanoparticles, such as metal particles, acetylene black particles, Ketjen black, and conductive carbon black. Furthermore, the granular form can generally be spherical or near-spherical. Even when exhibiting irregular geometric shapes, their three-dimensional dimensions (length, width, and height) are still roughly on the same order of magnitude, without significant directional extension.

[0087] One-dimensional (1D) materials typically refer to materials that exhibit a large aspect ratio (length / diameter) in three-dimensional space. This means that one dimension is large-scale, while the other two dimensions are relatively small. For example, only one dimension, such as length, is macroscopic, while the others, such as width and height (or diameter), are small, potentially at the nanoscale, resulting in a slender, linear or tubular structure. Typical examples include carbon nanotubes and carbon nanowires.

[0088] Two-dimensional (2D) materials typically refer to materials that have a large planar dimension and a thin thickness in three-dimensional space (thickness refers to the dimension perpendicular to the plane, which can be measured by atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and optical microscopy). That is, the dimension in one dimension is small, while the other two dimensions are large. For example, the dimension in only one dimension is at the nanoscale (usually the thickness), while the other two dimensions are at the macroscale, and the whole material presents a sheet or layered structure. Typical materials include graphene and carbon nanosheets.

[0089] In this invention, particle size refers to the diameter or equivalent diameter of a particle, used to characterize the size of the particle. For regular spherical particles, particle size is its geometric diameter; for non-spherical particles, particle size is usually expressed as "equivalent particle size", which can be calculated by methods such as geometric equivalent particle size and volume equivalent particle size. In this invention, the volume equivalent particle size measurement method is used to measure the diameter of spherical particles.

[0090] In this invention, the sheet diameter (or surface length) of a two-dimensional conductive material refers to the lateral dimension of the two-dimensional material in a plane, usually expressed as "equivalent diameter" or "characteristic length" to describe the size of the sheet. Generally, circular sheets are expressed as diameter, while irregular sheets are usually expressed as the length of the longest diagonal or as equivalent diameter (defined as the diameter of a circle with the same projected area as the sheet). This invention adopts the definition of equivalent diameter.

[0091] Due to the application of the above-described technical solution, the present invention has at least the following advantages compared with the prior art:

[0092] First, as a result of in-depth research to solve the above problems, this invention proposes a renewable energy storage unit (rust battery) based on the reaction mechanism of rust (ferric oxide). It utilizes the reversible oxidation-reduction properties of iron oxide to construct an electrochemical energy conversion mechanism. Combined with an air cathode and an aqueous electrolyte, a novel energy storage unit that can be charged and discharged in a cycle can be constructed. After assembly, it can be directly charged and used, has rapid response capability and active scheduling capability, can be applied to large-scale long-term energy storage and is conducive to on-site deployment for sudden needs. It can work in conjunction with intermittent power generation systems and has significant industrial practical value.

[0093] Second, at the same time, through further experimental research, this invention innovatively proposes a multilayer current collector structure with gradient aperture to hold the active material layer, and sets up a discrete active material layer, which can be a single layer or multiple layers spaced apart from the current collector. Thus, (1) the gradient aperture design and optimized structural stacking form can set up discrete multilayer active material layers, which can increase the overall active material loading in a limited area, and make the electrolyte easier to diffuse and penetrate into the interior, promoting all active materials to participate in the electrochemical reaction process, suitable for making thick electrodes, and improving the single cell capacity;

[0094] (2) Using a current collector with relatively smaller pores to contact the active material layer is beneficial for confining and coating the active material and enabling electron conduction. It also helps to improve the stability of the active material layer during the reaction process, making it less likely to fall off the current collector or lose electrical contact with it, thus improving cycle stability. When the first current collector is further stacked, the large pores of the first current collector allow more electrolyte to enter to improve the diffusion and penetration effect. At the same time, the first current collector itself also provides good support for the second unit as a whole and can act as an external conductor to provide more efficient electron conduction, thereby avoiding the problem of insufficient electron transport capacity caused by using rust with low conductivity as an active ingredient. At the same time, this multilayer structure can also improve the structural stability of the electrode during the cycle.

[0095] (3) The present invention designs a sandwich structure unit, in which the active material layer can be formed by multiple sets of structural units, namely the first unit and the second unit, alternately arranged to form a thick electrode. After such arrangement, it was unexpectedly found that the electrode structure of the present invention improves the problem of hydrogen evolution at the negative electrode during the charging process of traditional iron-air batteries (the reason is that water at the negative electrode of the existing iron-air batteries may gain some electrons during the charging process, and thus a hydrogen evolution competition reaction occurs), which hinders the battery capacity. It is believed that this may be due to the discrete design of the active material layer, which increases the overall thickness while releasing more contact area of ​​the active material layer. In this way, the hydrogen gas evolved at the negative electrode can be easily desorbed and moved away from the surface of the active material, thereby avoiding the formation of bubbles by the evolved hydrogen gas that hinders the contact between the active material and the electrolyte, and allowing the active material to fully participate in the reaction.

[0096] Thirdly, as a further preferred embodiment, the present invention also designs the structure of the first current collector to actively increase the gap between it and other current collectors and the active material layer (i.e., to set up fluid channels to form a receiving cavity). After this design structure is combined with the first and second units that are stacked together, the channel can form a multi-path fluid conduction network after the current collector is stacked and attached to other current collectors and active materials. This not only facilitates the buffering and flow of electrolyte and increases the contact effect between active material and electrolyte, but also facilitates the flow of hydrogen gas evolved from the negative electrode through the channel and its outward bulging and discharge. This is equivalent to suppressing the anchoring of bubbles on the current collector, providing a directional floating path for bubbles, and making it more conducive to the escape of gas. Thus, it more effectively solves the problem that the battery capacity improvement is not significant after the active material layer is thickened. Attached Figure Description

[0097] Figure 1 This is a schematic diagram of the overall structure of the electrode sheet in exemplary case (1) of the present invention;

[0098] Figure 2 This is a schematic diagram of the electrode sheet from another perspective in an exemplary case (1) of the present invention;

[0099] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0100] Figure 4 This is a schematic diagram of the exploded structure of the electrode sheet in the exemplary case (1) of the present invention;

[0101] Figure 5 This is one of the structural schematic diagrams of the first current collector in exemplary case (1) of the present invention;

[0102] Figure 6 This is a second schematic diagram of the structure of the first current collector in exemplary case (1) of the present invention;

[0103] Figure 7 This is the third schematic diagram of the structure of the first current collector in exemplary case (1) of the present invention;

[0104] Figure 8 This is a schematic diagram of the exploded structure of the electrode sheet in exemplary case (2) of the present invention;

[0105] Figure 9 This is a schematic diagram of the exploded structure of the electrode sheet in exemplary case (3) of the present invention;

[0106] Figure 10 This is a schematic diagram of the exploded structure of the electrode sheet in exemplary case (4) of the present invention;

[0107] Figure 11This is a schematic diagram of the overall structure of the electrode sheet in exemplary case (5) of the present invention;

[0108] Figure 12 This is a schematic diagram of the electrode sheet from another perspective in exemplary case (5) of the present invention;

[0109] Figure 13 This is a schematic diagram of the exploded structure of the electrode sheet in exemplary case (5) of the present invention;

[0110] Figure 14 This is a schematic diagram of the structure of the second current collector and the third current collector in exemplary case (5) of the present invention;

[0111] Figures 1 to 14 In the attached figures, the following are the reference numerals: 1. First current collector; 11. First hole; 12. Fluid channel; 13. Electrode; 2. Second current collector; 3. Active material layer; 4. Third current collector; 51. Connecting part; 52. Current collector body;

[0112] Figure 15 This is a schematic diagram showing the escape of hydrogen gas evolved in the electrode sheet in an embodiment of the present invention;

[0113] Figure 16 This is a comparison diagram showing the changes in the active material layer before and after cycling between the multilayer electrode sheet of the present invention and the electrode sheet without a multilayer structure.

[0114] Figure 17 This is a comparison diagram of the state of the electrode sheet used in a specific case of the present invention before and after cycling;

[0115] Figure 18 This is a schematic diagram of the structure of the rust-resistant battery in an embodiment of the present invention;

[0116] Figure 19 This is a cycle performance test diagram of Embodiment 2-1 of the present invention;

[0117] Figure 20 This is a cycle performance test diagram of Comparative Example 2-1 of the present invention;

[0118] Figure 21 This is a cycle performance test diagram of Comparative Example 2-2 of the present invention;

[0119] Figure 22 The graphs show the cyclic performance test results of Comparative Examples 2-3 of this invention. Detailed Implementation

[0120] Based on in-depth research and extensive experiments, the inventors of this invention have for the first time proposed a novel energy storage mechanism that enables the storage and release of energy through a reversible reaction between rust and iron, thus constructing a novel rechargeable and cyclical energy storage mechanism. Furthermore, they proposed a sandwich structure made of a multilayer current collector with a pore size gradient suitable for the active components of rust and an active material layer. For example, a basic structural unit is formed by sandwiching an active material layer between two layers of current collectors with small pores, and another structural unit is formed by a current collector with relatively large pores, which serves as an auxiliary support, air conduction, and electrical conduction function. Multiple sets of units are stacked alternately, thereby effectively solving the problem of neglecting one aspect for another in the prior art.

[0121] Based on this, the present invention relates to and provides a novel electrode sheet with outstanding performance. The electrode sheet includes a first unit and a second unit stacked on top of each other. The first unit includes a first current collector having a first hole. The second unit includes a second current collector, an active material layer, and a third current collector stacked on top of each other. A second hole is formed on the second current collector, and a third hole is formed on the third current collector. The pore diameter of the second hole and the pore diameter of the third hole are both smaller than the pore diameter of the first hole. The active material layer contains ferric oxide.

[0122] Furthermore, the first unit has m units arranged sequentially, where m is greater than or equal to 2, and at least one second unit is placed between any two adjacent first units. In some specific cases, there are n second units, where m = n + 1, for example, the second units can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The first units and the second units are stacked sequentially in the same direction.

[0123] The above-mentioned electrode plates will be further explained below with several specific exemplary cases.

[0124] Exemplary Case (1):

[0125] like Figures 1 to 7 As shown, an exemplary electrode sheet is provided, which includes a first unit and a second unit stacked on top of each other. The first unit includes a first current collector 1 with a first hole 11. The second unit includes a second current collector 2, an active material layer 3 and a third current collector 4 stacked on top of each other in sequence. The second current collector 2 has a second hole (not shown) and the third current collector 4 has a third hole (not shown). The diameter of the second hole and the diameter of the third hole are both smaller than the diameter of the first hole 11.

[0126] The first unit has m units arranged sequentially, where m is greater than or equal to 2, and a second unit is placed between any two adjacent first units. Further, there are n second units, where m = n + 1. That is, only one second unit is placed between any two adjacent first units. All first units and all second units are stacked sequentially in the same direction.

[0127] The number of units in the second category can be selected as needed, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In this example, there are 3 units in the second category. See [link to other resources] for details. Figure 4 The exploded structure diagram shown has four first current collectors 1. In this example, the electrode components are arranged in the following order: first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, forming an alternating stacked sandwich structure.

[0128] Furthermore, the present invention also designs the first current collector, wherein a receiving cavity communicating with the outside is formed between the first current collector 1 and the corresponding second current collector 2, and between the first current collector 1 and the corresponding third current collector 4. This receiving cavity has an opening facing the active material layer 3. Thus, this receiving cavity not only allows the electrolyte to flow rapidly to the active material layer 3, achieving rapid penetration and fully utilizing the function of the active material layer—especially by using multiple separately arranged active material layers, which greatly increases the effective contact area—but also allows the gas generated by the active material layer during the reaction process to be discharged, preventing gas accumulation from hindering the contact between the electrolyte and the active material layer, and also preventing gas accumulation from harming the structural stability and safety of the battery.

[0129] Specifically, in this example, the first current collector 1 is also provided with a fluid channel 12 communicating with the first hole 11. The fluid channel 12 can also communicate with the second hole on the corresponding second current collector 2 or the third hole on the corresponding third current collector 4, thereby obtaining a space that can both conduct gas and allow electrolyte to flow and diffuse. There are multiple fluid channels 12, and some or all of the fluid channels 12 extend to the edge of the first current collector 1 and can communicate with the outside. For example, the fluid channels 12 near the outside extend to the edge of the first current collector 1 and can communicate with the outside, while the flow channels 12 near the inside are indirectly communicated with the outside through the first hole 11 or other adjacent fluid channels. This not only helps to induce and guide the electrolyte to permeate into the active material layer 3 from multiple directions, increasing the diffusion and permeation effect, but also allows the hydrogen produced by the hydrogen evolution competition reaction to diffuse outward from the edge of the current collector, avoiding accumulation. Furthermore, alternatively, some of the fluid channels 12 are interconnected, or all of the multiple fluid channels 12 are interconnected. In this example, all fluid channels 12 are directly or indirectly connected to form an extension path with multiple directions, thus forming a multi-directional conductive network. This facilitates the diffusion of gas in various directions under the action of buoyancy by the channel network. After the gas escapes, the electrolyte quickly fills the pore space vacated by the gas due to its fluidity and spontaneous wetting properties, avoiding the formation of "air gaps" and ensuring that the active material is always encapsulated by the electrolyte, maintaining electron transport efficiency.

[0130] The first hole 11 has at least one side connected to the fluid channel 12. In this example, connection ports connected to the fluid channel 12 are opened on multiple sides of the first hole 11, so that all the first holes 11 and all the fluid channels 12 can be interconnected, further improving the diffusion and permeation efficiency of the electrolyte and providing an escape path for easy gas discharge.

[0131] Fluid channels 12 are formed on both opposite sides of the first current collector 1, and at least one of the aforementioned opposite sides faces the active material layer. For example... Figure 4 As shown, the two outermost first current collectors 1 have only one side facing the active material layer 3, while the two sides of the inner first current collectors 1 each face an active material layer 3. This facilitates the interconnection of the internal channels of the overall electrode structure, improves the diffusion and penetration efficiency of the electrolyte, and helps the evolved gas to be discharged or escape from different directions.

[0132] The depth of fluid channel 12 along the thickness direction of the first collector (e.g.) Figure 7 The depth (represented by h) and the width of fluid channel 12 (e.g., h represents the depth) Figure 7The ratio of the width (represented by w) is 1:0.5-12, for example, it can be 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, etc. The depth of the fluid channel 12 along the thickness direction of the first collector is greater than or equal to 0.1 mm, for example, 0.1-3 mm, further 0.2-3 mm, and even further 0.5-1.5 mm. Alternatively, the thickness can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.1mm, 2.3mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, etc. The width of the fluid channel 12 is 2-9mm, and can be further 3-7mm, for example, it can be 2mm, 2.1mm, 2.3mm, 2.5mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.3mm, 3.5mm, 3.7mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6.5mm, 6.8mm, 7mm, 7.2mm, 7.5mm, 7.8mm, 8mm, 8.2mm, 8.5mm, 8.8mm, etc.

[0133] In this example, the first current collector 1 also provides good support for the second unit as a whole. Therefore, the thickness of the first current collector 1 is greater than the thickness of the second current collector 2 and the third current collector 4, which helps to improve the structural strength. The thickness of the first current collector 1 can be 5-30 times, or even 10-20 times, the thickness of the second current collector 2 and the third current collector 4. For example, it can be, but is not limited to, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 times, etc. Optionally, the thickness of the first current collector 1 can be 1-7mm, further 1-5mm, for example, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6.5mm, 6.8mm, etc.

[0134] The mesh count of the second hole and the third hole are 100-1000 mesh, further 150-800 mesh, and even further 200-750 mesh. Optionally, the mesh count of the second hole and the third hole can be 100 mesh, 150 mesh, 200 mesh, 250 mesh, 300 mesh, 350 mesh, 400 mesh, 450 mesh, 500 mesh, 550 mesh, 600 mesh, 650 mesh, 700 mesh, 750 mesh, 800 mesh, 850 mesh, 900 mesh, 950 mesh, 1000 mesh, etc.

[0135] See Figure 1 , Figures 5-6As shown, the first holes 11 on the first current collector 1 are not evenly distributed in terms of area, but are interspersed with fluid channels 12. The diameter of the first hole 11 is larger than that of the second and third holes, and can be set to 1-20mm, further to 4-12mm, for example, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6mm .5mm, 6.8mm, 7mm, 7.2mm, 7.5mm, 7.8mm, 8mm, 8.2mm, 8.5mm, 8.8mm, 9mm, 9.2mm, 9.5mm, 9.8mm, 10mm, 10.2mm, 10.5mm, 10.8mm , 11mm, 11.2mm, 11.5mm, 11.8mm, 12mm, 12.2mm, 12.5mm, 12.8mm, 13mm, 13.5mm, 14mm, 14.5mm, 15mm, 16mm, 17mm, 18mm, 19mm, etc. To ensure the diffusion efficiency of the first current collector 1 for the electrolyte and the evolved gas, there are multiple first holes 11. Preferably, the sum of the opening areas of each first hole 11 accounts for 10%-70% of the corresponding opening plane area of ​​the first current collector 1, for example, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 30%, 32%, 35%, 40%, 45%, 48%, 50%, 55%, 60%, 65%, 68%, etc.

[0136] Furthermore, the cross-sectional shape of the first hole 11 is not specifically limited, and may include, but is not limited to, a circular, square, rhomboid, triangular, star-shaped, petal-shaped, irregular, or free-form curved shape. The shape of the fluid channel 12 is also not specifically limited, and may include, for example, a rectangular, trapezoidal, or arc-shaped shape. The fluid channel itself is also not specifically limited; it may be a straight channel, or an S-shaped, serpentine, wavy, dendritic, or honeycomb-shaped channel, etc. Figure 5 As shown, the first hole 11 is a through hole, and the fluid channel 12 is a semi-closed groove.

[0137] The first current collector 1, the second current collector 2, and the third current collector 4 are made of either metallic conductive materials or non-metallic conductive materials. Further, the metallic conductive materials include stainless steel, nickel or its alloys, copper alloys, or aluminum alloys, while the non-metallic conductive materials include conductive carbon materials or conductive polymer materials. For example, the first current collector 1, the second current collector 2, and the third current collector 4 can all be made of stainless steel, specifically 304 stainless steel. The first current collector 1 uses a relatively thick stainless steel plate with a first hole 11 and a fluid channel 12 formed on it. The second current collector 2 and the third current collector 4 are both stainless steel meshes. The stainless steel mesh can be formed using conventional processes including, but not limited to, weaving, punching, laser cutting, and rolling stretching, and is commercially available.

[0138] The electrode plate also includes tabs 13 formed on the first current collector 1; when there are multiple first current collectors 1, the tabs 13 of each first current collector 1 are connected together, see [reference]. Figure 1 As shown, when stacked together, the individual tabs 13 are connected by welding and / or fastening, which is beneficial for electronic transmission and structural stability. Fastening methods include, but are not limited to, using conductive fasteners to directly or indirectly fasten the tabs together. For example, direct fastening can be achieved by connecting and fastening the tabs together with conductive components such as long screws. Indirect fastening methods include adding conductive gaskets, such as stainless steel gaskets, or filling the gaps between the tabs with gaskets, and then fastening them all together with screws or other methods. Of course, in some implementations, busbars can be used for pressing.

[0139] As an optional implementation, the first current collector is provided with tabs. Stainless steel gaskets are placed between each tab, the thickness of which can be selected based on the width between two adjacent tabs. Holes are drilled at the same location on each tab and the stainless steel gasket, and then screws are used for tightening. Corresponding wires are led out from the tail end to connect to the external circuit. Furthermore, to ensure that the tabs do not come into contact with the electrolyte as much as possible, heat shrink tubing or similar methods can be used to protect the corresponding parts to prevent problems such as alkali creep.

[0140] The outer peripheries of the first current collector 1, the second current collector 2, and the third current collector 4 are connected together, which helps to ensure the stability of the overall structure, firmly fixes the internal active material layer 3, and prevents problems such as shedding during the electrochemical cycle of the battery. The connection method includes, but is not limited to, welding or fastening with fasteners.

[0141] Welding methods include, but are not limited to, single or combined forms such as spot welding, seam welding, laser welding, and ultrasonic welding.

[0142] The hardness of the first current collector 1 is greater than that of the second current collector 2 and the third current collector 4. The second current collector 2 and the third current collector 4 can be bent and deformed, which can be achieved by selecting the thickness mentioned above. The second current collector 2 and the third current collector 4 are directly attached to the active material layer 3. Therefore, selecting a current collector that can be bent and deformed can fit more closely to the active material layer 3, achieving the purpose of tightly confining and wrapping the active material layer 3, thereby improving stability and electron conductivity. The first current collector 1, which has a higher hardness on the outside, provides rigid support and can also prevent unnecessary damage or detachment of the internal active material layer 3 during installation, transportation and operation, resulting in better overall stability.

[0143] The second current collector 2 and the third current collector 4 can be the same.

[0144] Further, see Figures 1 to 3 As shown, after the stacked layers form the electrode sheet, the multi-layered active material layer 3 in the middle is separated and set separately, sandwiched between the current collectors. This structure allows the electrolyte to permeate into the interior from all directions through the fluid channel 12 and the first hole 11, while the gas inside can also escape to the outside from all directions. In this way, more active material layers 3 can be set, thereby increasing the amount of active material to improve the battery capacity (improving the problem in the prior art that even if the active material is made thicker, the battery capacity is not significantly improved and the capacity is not well utilized). Moreover, with this structure, the active material is not easy to fall off the current collector during the battery cycle, and it is less likely to lose electrical contact with the current collector.

[0145] Furthermore, Figure 4 This is a schematic diagram of the exploded structure of the electrode sheet in this example. Figure 4 The layers are arranged in sequence and stacked together during fabrication, with the edges firmly connected by welding or other methods.

[0146] Furthermore, Figures 5-7 An exemplary schematic diagram of the structure of the first current collector 1 used in this example is given. This structural design actively increases the gap between the current collector and other current collectors and the active material layer (i.e., fluid channels 12 are set to form a receiving cavity). After this design structure is combined with the first unit and the second unit that are superimposed on each other, the channel can form a multi-path fluid conduction network after the current collector is stacked and attached to other current collectors and active materials. This network not only facilitates the wetting of the active material in the electrolyte, but also provides a directional channel for the hydrogen gas evolved from the negative electrode, promotes the gas to escape outward, and reduces the retention and anchoring of bubbles on the surface of the current collector. This more effectively solves the problem that the battery capacity is not significantly improved after the active material layer is thickened.

[0147] Exemplary Case (2):

[0148] This example provides an electrode sheet, basically the same as the exemplary case (1), the only difference being: the number of second units is 2, and the number of first current collectors is 3. The components of the electrode sheet in this example are arranged in the following order: first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1. See the exploded structural diagram for details. Figure 8 As shown.

[0149] Exemplary Case (3):

[0150] This example provides an electrode sheet, basically the same as the exemplary case (1), the only difference being: the number of second units is 4, and the number of first current collectors is 5. The components of the electrode sheet in this example are arranged in the following order: first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1. See the exploded structural diagram for details. Figure 9 As shown.

[0151] Exemplary Case (4):

[0152] This example provides an electrode sheet, basically the same as the exemplary case (1), the only difference being: the number of second units is 6, and the number of first current collectors is 7. The components of the electrode sheet in this example are arranged in the following order: first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1. See the exploded structural diagram for details. Figure 10 As shown.

[0153] Exemplary Case (5):

[0154] This example provides an electrode sheet, basically the same as in exemplary case (1), except that the structures of the second current collector 2 and the third current collector 4 are partially different. Specifically, in this example, the second current collector 2 and the third current collector 4 have added connecting parts. See also Figures 11 to 14As shown, the second current collector 2 and the third current collector 4 are each provided with a connecting part 51, which can be connected to the first current collector 1. The connecting part 51 is located on the side of the corresponding second current collector 2 or third current collector 4, and the length direction of the connecting part 51 is parallel to the length direction of the corresponding second current collector 2 or third current collector 4.

[0155] In this example, the connecting portion 51 is connected to the first current collector 1, which is spaced apart from it by the active material layer 3, and the width of the connecting portion 51 extends toward the side adjacent to the active material layer 3. The connecting portions 51 on the second current collector 2 and the connecting portions 51 on the third current collector 4 are located on opposite sides of the electrode plates.

[0156] Further, see Figure 11 and 12 As shown, after the electrode plates in this example are stacked together, the connecting parts can be seen on both sides covering the side surface of the first current collector. They can be stably connected together by welding or other means, which is equivalent to providing a grip for the second unit to be firmly fixed on the first current collector.

[0157] like Figure 13 As shown in the enlarged structural diagram, the connection relationship is as follows: the connecting part on the second current collector 2 on the left is connected to the first current collector 1 on the right, while the connecting part on the third current collector 4 on the right is connected to the first current collector 1 on the left. This cross connection helps to firmly confine the intermediate layer and improve the stability of the overall structure.

[0158] Specifically, the second current collector 2 and the third current collector 4 independently include a current collector body 52 and the aforementioned connecting portion 51. The current collector body 52 and the connecting portion 51 are integrally formed to constitute the corresponding second current collector 2 or third current collector 4, such as... Figure 14 As shown.

[0159] Exemplary Case (6):

[0160] This example provides an electrode sheet, basically the same as in exemplary case (1), except that the surface of the first current collector is provided with a nickel-containing coating. Further, the nickel-containing coating is a nickel-phosphorus coating. For example, the phosphorus content in the nickel-phosphorus coating is 5 wt.%-20 wt.%, and more specifically 8 wt.%-12 wt.%. This coating can provide both conductivity and corrosion resistance. The processing methods for the nickel-containing coating include, but are not limited to, electroplating, laser cladding, spraying, sintering, etc., which are conventional processes and will not be described in detail here.

[0161] Furthermore, the thickness of the nickel-containing coating is 5-20 μm, further 6-18 μm, and even further 7-15 μm. Depending on some specific aspects, the thickness of the nickel-containing coating may include, but is not limited to, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0162] See Figure 15 As shown, the exemplary embodiment provides a schematic diagram of the discharge of gas such as hydrogen produced by the sandwich structure electrode sheet made of multilayer current collector structure with pore size gradient and active material layer of the present invention. After hydrogen is released from the active material layer, it can escape outward and upward through both sides, and the escape path is unobstructed.

[0163] Further, see Figure 16 As shown, this is a comparison diagram of the changes in the active material layer before and after cycling between the multilayer structure electrode sheet of the present invention and the electrode sheet without a multilayer structure. Due to the confinement effect of the structure of the present invention, the inner active material layer remains relatively stable during cycling, while the electrode sheet without a multilayer structure is prone to active material shedding.

[0164] Further, see Figure 17 As shown, this is a comparison diagram of the state of the electrode sheet (the active material layer is configured as a circle) used in a specific case of the present invention before and after cycling. It can be seen that no active material is seen to fall off on the electrode sheet of the present invention.

[0165] The active material layer of the present invention will be described below:

[0166] The thickness of the active material layer 3 can be set as needed, preferably 100-3000 μm, for example, including but not limited to 100 μm, 120 μm, 150 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, 1010 μm, etc. 1020μm, 1040μm, 1050μm, 1080μm, 1100μm, 1150μm, 1200μm, 1250μm, 1300μm, 1350μm, 1400μm, 1450μm, 1500μm, 1550μm, 1600μm, 1700μm, 1800μm, 1900μm, 2000μm, 2100μm, 2200μm, 2300μm, 2500μm, 2600μm, 2800μm, 2900μm, etc.

[0167] The shape of the active substance layer can be square, circular, elliptical, etc.

[0168] In some solutions, the active material layer includes the following three technical solutions:

[0169] Option 1: The active material layer comprises ferric oxide, a conductive agent, and a binder. Further, by mass percentage, the conductive agent accounts for 10%-30%, ferric oxide for 60%-80%, and the binder for 1%-15% of the active material layer. Even further, by mass percentage, the conductive agent accounts for 15%-25%, ferric oxide for 65%-75%, and the binder for 7%-13% of the active material layer. The conductive agent can be a two-dimensional conductive material, such as graphene.

[0170] Option 2: The active material layer includes a rust electrode material, which comprises a two-dimensional conductive material, ferric oxide loaded on the two-dimensional conductive material, a zero-dimensional conductive material, and a one-dimensional conductive material; wherein, the two-dimensional conductive material forms a basic framework (providing a large area for ferric oxide deposition), the zero-dimensional conductive material and the one-dimensional conductive material respectively form an epitaxial framework, and the basic framework and the epitaxial framework together constitute an interconnect framework (the interconnect structure has a confinement effect, which can restrict the aggregation and migration behavior of ferric oxide on a spatial scale and significantly improve its deposition capacity), and ferric oxide is distributed in the interconnect framework.

[0171] Option 3: The active material layer comprises a rust-colored electrode material, which includes a two-dimensional conductive material, ferric oxide loaded on the two-dimensional conductive material, a zero-dimensional conductive material, and a one-dimensional conductive material. Specifically, by mass percentage, the two-dimensional conductive material accounts for 10%-40% of the active material layer, and the amount of the two-dimensional conductive material added is more than 1.5 times the amount added of either the zero-dimensional or one-dimensional conductive material. Option 3 can also form the interconnect framework of Option 2.

[0172] By constructing an interconnected framework, specifically by introducing conductive materials of three dimensions—point, line, and surface—into the negative electrode, with two-dimensional conductive materials serving as the main basic framework structure, supplemented by an extended framework formed by zero-dimensional and one-dimensional conductive materials, the three work together to construct a multi-dimensional interconnected framework. This helps to solve the problems of existing iron-air batteries, such as their inapplicability to deployments for sudden needs and the trade-offs in processing iron negative electrodes.

[0173] This active material layer uses rust, i.e., ferric oxide, as the core active material, supplemented by conductive materials of various dimensions. The inventors of this invention are the first to propose using a two-dimensional conductive material as a deposition carrier, loading ferric oxide onto it, and combining it with one-dimensional and zero-dimensional conductive materials to form an extended network-like epitaxial framework. The two-dimensional conductive material serves as the main basic framework structure, enabling the loading of more active materials. Through the synergistic effect of the three conductive materials, an interconnected core-external framework can be formed inside the electrode. This multi-pathway and three-dimensional conductive network construction:

[0174] Firstly, it can provide more and less obstructed electron transport and transfer paths, which can effectively shorten the path of electrons from the active material to the current collector, thus improving electron conduction ability, conductivity and utilization of active materials.

[0175] Secondly, the interconnected framework can be used to stably confine ferric oxide or other active materials such as iron or ferrous hydroxide generated during the charging and discharging process within a certain spatial range. Simultaneously, it alleviates stress concentration caused by volume expansion during cycling, reducing the risk of cracking and significantly improving the stability of the electrode structure. In particular, the active materials are always confined within the interconnected framework, increasing their utilization rate and avoiding the drawback of "loss" during dissolution and redeposition during cycling, preventing their participation in electrochemical reactions. Furthermore, unexpectedly, the spatial range defined by the interconnected framework provides a pathway for the escape of hydrogen gas evolved from the negative electrode. This allows the present invention to better address the problem of difficult or impossible hydrogen escape from the negative electrode in conventional iron-air batteries, further enhancing battery capacity.

[0176] Furthermore, the simultaneous presence of the three conductive materials results in an ideal porosity in the prepared electrode, which is conducive to the migration of ions in the electrolyte and the smooth progress of electrochemical reactions. In addition, the strong porosity allows the electrolyte to quickly penetrate into the electrode, shortening the ion diffusion path and thus improving the charge transport efficiency. Moreover, the presence of these micropores can also provide sufficient buffer space for the negative electrode, which has volume changes, during the charging and discharging process, preventing the negative electrode structure from cracking, breaking or peeling.

[0177] Furthermore, the combined use of three types of conductive materials not only constructs a multi-dimensional interconnected framework but also provides better structural support for the overall structure. This facilitates the preparation of the anode of this invention using a solvent-free dry pressing molding process, which is simple, easy to repeat, and has good consistency. In contrast, if a conventional iron anode is prepared using a dry pressing molding process, it is very easy to cause excessively high compaction density, which cannot guarantee sufficient porosity. This results in difficulty in electrolyte penetration, and the active material is prone to loss, shedding, or significant migration during cycling, leading to low utilization and insufficient battery cycle performance.

[0178] Meanwhile, the combined use of the aforementioned conductive materials and the applicability of dry molding also allow for an increase in the amount of active material used in this invention (solvent-free, the proportion of active components can be increased), thereby increasing the areal loading of active components in the negative electrode, making it suitable for preparing thick electrodes.

[0179] This is a specific example of the rust electrode material of the present invention. Ferric oxide, a zero-dimensional conductive material, and a one-dimensional conductive material are all loaded onto a two-dimensional conductive material. These materials are mixed together, with the two-dimensional conductive material serving as the carrier, thereby constructing a three-dimensional interconnected framework structure with multiple conductive pathways in both the horizontal and vertical directions. This arrangement also ensures that any conductive pathway contains zero-dimensional, one-dimensional, and two-dimensional conductive materials, which not only have synergistic effects but also mutually confine each other, constructing a stable framework network structure.

[0180] Zero-dimensional conductive materials, one-dimensional conductive materials, and two-dimensional conductive materials can be any solid material with excellent conductivity. For example, they can all be conductive carbon materials. Conductive carbon materials come in various forms and are readily available, such as the zero-dimensional, one-dimensional, and two-dimensional conductive carbon materials required by this invention. They are commercially available or prepared using methods commonly used in the art. Zero-dimensional conductive carbon materials can be acetylene black particles, Ketjen black, conductive carbon black, etc.; one-dimensional conductive carbon materials can be carbon nanofibers, carbon nanotubes, etc.; and two-dimensional conductive carbon materials can be graphene, carbon nanosheets, etc.

[0181] The thickness of the two-dimensional conductive material is 1-300 nm, and the sheet diameter (or face length) is 0.5-20 μm. Further, the thickness of the two-dimensional conductive material is 5-200 nm, and the sheet diameter (or face length) is 1-20 μm. Even further, the thickness of the two-dimensional conductive material is 5-100 nm, and the sheet diameter (or face length) is 1-15 μm. According to some specific aspects of the invention, the thickness of the two-dimensional conductive material is 1-50 nm, and the sheet diameter (or face length) is 1-10 μm. Furthermore, the thickness of the two-dimensional conductive material can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 15 nm, 17 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, 33 nm, 35 nm, 36 nm, 38 nm, 40 nm, 42 nm, 43 nm, 44 nm, 45 nm, 46 nm, 48 nm, 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 130 nm, etc. The thicknesses of two-dimensional conductive materials can range from nm, 150nm, 180nm, 200nm, 250nm, and 280nm, with sheet diameters of 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 9.8μm, 10μm, 12μm, 13μm, 15μm, 16μm, 18μm, and 20μm. These materials are commercially available. However, in practice, the thickness and sheet diameter of two-dimensional conductive materials may not be entirely uniform, but rather fall within a general range.

[0182] The aspect ratio of one-dimensional conductive materials is 100-3000. Furthermore, the aspect ratio of the one-dimensional conductive material is 100-2500, or 110-2300, or 120-2000, or 130-1800, or 140-1500, or 150-1200, or 155-1800, or 155-1500, or 155-1200, or 155-1000, or 200-800, or 250-700, or 300-600, or 350-500, or 400-900, or 450-900, or 550-900, or 650-1500, or 600-1200, or 650-1000, or 700-900, or 750-850, etc.

[0183] The particle size of zero-dimensional conductive materials is 10-500 nm. Further, the particle size of zero-dimensional conductive materials is 10-100 nm. Even further, the particle size of zero-dimensional conductive materials is 12-450 nm, or 15-400 nm, or 20-450 nm, or 25-400 nm, or 30-350 nm, or 35-300 nm, or 40-350 nm, or 45-300 nm, or 50-250 nm, or 60-500 nm, or 65-450 nm, or 70-400 nm, or 75-350 nm, or 80-300 nm, or 85-250 nm, or 90-200 nm, or 95-150 nm, or 100-120 nm, etc.

[0184] Ferric oxide exists in the form of ferric oxide particles with a particle size of 10-1000 nm. Further, the particle size of the ferric oxide particles can be 12-950 nm, or 15-900 nm, or 20-850 nm, or 25-800 nm, or 30-750 nm, or 35-700 nm, or 40-650 nm, or 45-600 nm, or 50-550 nm, or 60-500 nm, or 65-450 nm, or 70-400 nm, or 75-350 nm, or 80-300 nm, or 85-250 nm, or 90-200 nm, or 95-150 nm, or 100-120 nm, etc.

[0185] In the rust electrode material, the mass ratio of zero-dimensional conductive material, one-dimensional conductive material, and two-dimensional conductive material is 1:0.1-10:1.5-40. Further, the mass ratio is 1:0.2-2.8:3-15. Even further, the mass ratio is 1:0.4-2.5:3.5-9.

[0186] In specific implementation cases, ferric oxide accounts for 50%-75% of the rust electrode material by mass percentage. For example, ferric oxide can account for 51%-55%, or 56%-58%, or 59%-62%, or 63%-65%, or 66%-68%, or 69%-70%, or 71%-72%, or 73%-74%, or 52%-57%, or 53%-61%, or 64%-67%, or 54%-57%, or 60%-69%, etc. Furthermore, by mass percentage, two-dimensional conductive materials account for 15%-40% of the rust electrode material, one-dimensional conductive materials account for 1%-10%, and zero-dimensional conductive materials account for 1%-10%. Even further, by mass percentage, the total content of one-dimensional and zero-dimensional conductive materials in the rust electrode material accounts for 5%-15%. Furthermore, by mass percentage, in rust electrode materials, two-dimensional conductive materials account for 18%-36%, one-dimensional conductive materials account for 3%-7%, and zero-dimensional conductive materials account for 3%-7%.

[0187] In this invention, the interconnect framework constructed by the above ratio in the active material layer can achieve excellent synergistic effect with ferric oxide. After being made into a negative electrode, it can obtain better conductivity and cycle stability. The utilization rate of ferric oxide is high, which is conducive to the preparation of air batteries with better performance.

[0188] Furthermore, the active material layer also includes a binder comprising 1%-10% of the rust electrode material by mass percentage. The binder may include, but is not limited to, polytetrafluoroethylene (PTFE), hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), etc., and one or more combinations may be selected. The mass content of the binder in the rust electrode material may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0189] The active material layer is prepared by the following method:

[0190] The components of the active material layer are mixed and homogenized to form an active material mixture.

[0191] The active material mixture is pressed into an active material layer, or the active material mixture is integrally formed between the second current collector and the third current collector to form a second unit, thereby obtaining an active material layer.

[0192] Furthermore, the mixing and homogenization are carried out using a dry mixing method.

[0193] According to one specific aspect, in the process of preparing the active material layer: under solvent-free conditions, ferric oxide and two-dimensional conductive materials are first mixed and stirred to obtain an intermediate. Then, zero-dimensional conductive materials and one-dimensional conductive materials are added to the intermediate, and the mixture is stirred and stirred again. Finally, a binder is added and mixed evenly to prepare an active material mixture.

[0194] Before forming the active material layer, the active material mixture is treated by rolling, grinding or shearing to cause the binder to become fibrous.

[0195] According to one specific aspect, the active material layer is the layered structure formed by the rust electrode material.

[0196] A rust-resistant battery consists of a negative electrode, an air positive electrode, and an electrolyte. The battery assembly structure can be found in [reference needed]. Figure 18 The assembly of the conventional iron-air battery shown differs in that the negative electrode is made of a material containing the electrode sheet described above in this invention.

[0197] Furthermore, the negative electrode for the air battery includes the aforementioned electrode sheet, or the aforementioned electrode sheet can be used directly as the negative electrode sheet. The active material layer is sandwiched between various current collectors. When the active component in the active material layer is in direct contact with the current collector, electrons are directly conducted through the current collector, for example, electrons are transferred out or to the active component through the current collector. When the active component is not in direct contact with the current collector, electrons are transferred in and out through a multi-path interconnected framework that is not easily blocked. Due to the form of a three-dimensional interconnected conductive path, electrons can be quickly transferred between the active component and the current collector, greatly improving the electron conduction capability.

[0198] Furthermore, in the present invention, when preparing the electrode sheet, a flat plate cold pressing device can be used to stack the units and then press them together. The pressure is set to 0.1-4 MPa, and the pressing time is about 0.5-5 min, or more specifically 1-2 min. After pressing, the perimeter of each current collector structure is sealed and welded (the method includes, but is not limited to, single or combined forms of spot welding, seam welding, laser welding, ultrasonic welding, etc.), and fasteners are used to fix it, so as to form a stable integrated structure and prevent interlayer slippage and active material shedding during charging and discharging.

[0199] Air cathodes can use existing conventional structures and materials without any particular restrictions.

[0200] An air positive electrode can be prepared as follows: a solvent, Nafion (perfluorosulfonic acid resin) solution, a catalyst, and a conductive agent are mixed to form a positive electrode slurry. This slurry is then coated onto a positive electrode current collector and dried to obtain an air positive electrode. Further, the solvent can be water and / or alcohol, where the alcohol can be ethanol; the catalyst can be a bifunctional or mixed material with OER and ORR catalytic activity, such as RuO2, Pt / C, or mixtures thereof; the conductive agent can be carbon black; and the positive electrode current collector can be carbon paper.

[0201] The electrolyte used is the same as that used in air batteries, which will not be described in detail here.

[0202] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0203] Unless otherwise specified in the following examples, all raw materials were commercially available or prepared using conventional methods in the art. In the examples below, the ferric oxide particles had a particle size of approximately 100 nm and were purchased from Xi'an Bona Materials Technology Co., Ltd.; the graphene was commercially available with a thickness of approximately 1-10 nm and a sheet diameter of approximately 1-10 μm, purchased from Xiamen Kaina Graphene Technology Co., Ltd.; the carbon nanotubes had a diameter of 10-30 nm and a length of 10-30 μm, purchased from Chengdu Jiacai Technology Co., Ltd.; and the acetylene black was purchased from Kelude, with a particle size of approximately 35 nm, product number MA-EN-CO-000601.

[0204] (Electrode sheets and their preparation)

[0205] Example 1-1:

[0206] This example provides an electrode sheet and its preparation method. The structure of the electrode sheet is as described in the exemplary case (1) above. Figures 1 to 7 The structure shown includes four first units and three second units, arranged in the order of first unit, second unit, first unit, second unit, first unit, second unit, and first unit. The first unit is the first current collector, specifically arranged in the order of first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, first current collector 1, second current collector 2, active material layer 3, third current collector 4, and first current collector 1, forming an alternating stacked sandwich structure.

[0207] The first current collector 1 is a stainless steel plate, and its structure is described in [reference needed]. Figure 5-7As shown, in this example, its planar dimensions are set to 70mm*90mm, the thickness is 3mm, the diameter of the first hole is 8mm, and the holes are arranged in a pattern of 5×8=40, with 5 holes in the direction of the short side dimension of 70mm and 8 holes in the direction of the long side dimension of 90mm. The ratio of the depth of the fluid channel along the thickness direction of the first collector to the width of the fluid channel is 1:5, and the depth of the fluid channel along the thickness direction of the first collector is 1mm.

[0208] The first current collector is equipped with tabs. A stainless steel gasket with a thickness of about 0.9mm is placed between each tab. Holes are drilled at the same position on each tab and the stainless steel gasket, and then screws are used to tighten them. When assembling the battery later, wires are led out from the tail end to connect to the external circuit.

[0209] The second and third current collectors are the same and both are made of stainless steel mesh. The stainless steel mesh has a planar size of 70mm*90mm and a thickness of 200μm. The mesh count of the second and third holes is 500 mesh.

[0210] The thickness of the active material layer is 500μm, and the planar dimensions of the active material layer are 50mm*70mm.

[0211] By mass percentage, the active material layer contains 70% rust particles (i.e., ferric oxide particles, the same below), 20% graphene, and 10% PTFE (polytetrafluoroethylene).

[0212] Methods for preparing electrode sheets include:

[0213] First, 70% of rust (Fe2O3) particles and 20% of graphene are mechanically mixed for 30 minutes using a high-speed mixer (about 2500 rpm). Then, 10% of PTFE is added, and the mixture is mixed for another 15 minutes using a high-speed mixer (about 3000 rpm) to obtain the active material. The active material is then uniformly placed in a 50mm*70mm mold and pressed under a pressure of 6MPa to obtain the active material layer.

[0214] The first current collector, the second current collector, the active material layer, and the third current collector are stacked according to the above-mentioned arrangement structure, and then pressed. The pressure is set to 1MPa and the pressing time is 2min. Spot welding is performed on the edges of each current collector layer after pressing.

[0215] For the protruding tabs of the stainless steel plate, place stainless steel washers with a thickness of about 0.9mm between each tab. Drill holes at the same position on each tab and stainless steel washer, and then tighten them with through screws.

[0216] Examples 1-2:

[0217] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that the electrode sheet includes 3 first units and 2 second units. The exploded view of the electrode sheet is shown in the above exemplary case (2). Figure 8 The structure shown.

[0218] Examples 1-3:

[0219] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that the electrode sheet includes 5 first units and 4 second units. The exploded view of the electrode sheet is shown in the above exemplary case (3). Figure 9 The structure shown.

[0220] Examples 1-4:

[0221] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that the electrode sheet includes 7 first units and 6 second units. The exploded view of the electrode sheet is shown in the above exemplary case (4). Figure 10 The structure shown.

[0222] Examples 1-5:

[0223] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that the ratio of the depth of the fluid channel along the thickness direction of the first current collector to the width of the fluid channel is 1:10, and the depth of the fluid channel along the thickness direction of the first current collector is 0.2 mm.

[0224] Examples 1-6:

[0225] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that: the diameter of the first hole is 10mm, the holes are arranged in a pattern of 3×5=15, with 3 holes in the direction of the short side dimension of 70mm and 5 holes in the direction of the long side dimension of 90mm; the mesh count of the second and third holes is 300 mesh.

[0226] Examples 1-7:

[0227] This example provides an electrode sheet and its preparation method, which are basically the same as those in Example 1-1, except that no fluid channel is provided on the first current collector.

[0228] Examples 1-8:

[0229] This example provides an electrode sheet and its preparation method, which are basically the same as those in Examples 1-1, except that: by mass percentage, the active material layer contains 95% rust electrode material and 5% PTFE (polytetrafluoroethylene).

[0230] By mass percentage, the rust electrode material contains 63% rust particles (i.e., ferric oxide particles, the same below), 27% graphene, 5% carbon nanotubes, and 5% acetylene black.

[0231] The preparation method of the active material layer includes: first, mechanically mixing 63% rust (Fe2O3) particles and 27% graphene in a high-speed mixer (about 2500 rpm) for 30 min; then adding 5% carbon nanotubes and 5% acetylene black, and continuing to mix for 30 min to obtain rust electrode material; then mixing the rust electrode material and binder in a high-speed mixer (stirring speed of 3000 rpm) for 15 min to prepare rust electrode material; then uniformly placing the rust electrode material in a 50mm*70mm mold and pressing it under a pressure of 6MPa to obtain the active material layer.

[0232] Examples 1-9:

[0233] This example provides an electrode sheet and its preparation method, which are basically the same as those in Examples 1-8, except that: by mass percentage, the rust electrode material contains 72% rust particles, 18% graphene, 5% carbon nanotubes, and 5% acetylene black.

[0234] Examples 1-10:

[0235] This example provides an electrode sheet and its preparation method, which are basically the same as those in Examples 1-8, except that: by mass percentage, the rust electrode material contains 63% rust particles, 3% graphene, 20% carbon nanotubes, and 14% acetylene black.

[0236] Comparative Example 1-1:

[0237] This example provides an electrode sheet and its preparation method, which are basically the same as those in Example 1-1, except that the first current collector does not have a first hole.

[0238] Comparative Examples 1-2:

[0239] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that: the first current collector is not provided, and electrode tabs are welded onto the second current collector and the third current collector respectively.

[0240] Comparative Examples 1-3:

[0241] This example provides an electrode sheet and its preparation method, which is basically the same as in Example 1-1, except that the ferric oxide particles are replaced with ferric oxide particles of the same amount and particle size.

[0242] (Rust-resistant batteries and their preparation)

[0243] Example 2-1:

[0244] This example provides a rust battery, which includes a negative electrode, an air positive electrode, and an electrolyte. The negative electrode uses the electrode sheet obtained in Example 1-1 as the negative electrode for the air battery. Figure 18 Assembly;

[0245] The air cathode was prepared as follows: 0.5 mL of deionized water, 0.5 mL of ethanol, 50 μL of Nafion solution (DuPont, USA, Nafion solution DUPONT 5% D520 perfluorosulfonic acid naphthol membrane solution), 3 mg of Pt-Ru / C catalyst (platinum-ruthenium carbon black 40% Pt-20% Ru / C, purchased from Shaanxi Kaida Chemical Co., Ltd.) and 2 mg of carbon black (particle size about 30-60 nm, Vulcan XC-72, purchased from the Scientific Materials Station) were mixed and ultrasonicated for 60 min to obtain a cathode slurry. An appropriate amount of cathode slurry was coated onto carbon paper (thickness of 0.3 mm) and dried at room temperature to obtain an air cathode with a thickness of 0.36 mm.

[0246] The electrolyte is an aqueous solution of potassium hydroxide with a concentration of 6 mol / L.

[0247] Example 2-2:

[0248] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-2.

[0249] Examples 2-3:

[0250] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-3.

[0251] Examples 2-4:

[0252] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-4.

[0253] Examples 2-5:

[0254] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-5.

[0255] Examples 2-6:

[0256] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Examples 1-6.

[0257] Examples 2-7:

[0258] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-7.

[0259] Examples 2-8:

[0260] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Examples 1-8.

[0261] Examples 2-9:

[0262] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-9.

[0263] Example 2-10:

[0264] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode for air batteries obtained in Example 1-10.

[0265] Comparative Example 2-1:

[0266] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode used in the air battery obtained in Comparative Example 1-1.

[0267] Comparative Example 2-2:

[0268] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode used in the air battery obtained in Comparative Example 1-2.

[0269] Comparative Examples 2-3:

[0270] This example provides a rust battery, which is basically the same as Example 2-1, except that the negative electrode is the negative electrode used in the air battery obtained in Comparative Examples 1-3.

[0271] Performance testing:

[0272] Charge-discharge experiments were conducted on the rust-bearing batteries obtained in Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-3, wherein: the charge-discharge rate was 0.1C; the test temperature was 25℃, room temperature; the charge-discharge experiment process was as follows: the voltage test range was 0.1-2V. After assembling the battery, it was first left to stand for 10 hours, then charged at a current of 0.1C for 10 hours with a cutoff voltage of 2V, then left to stand for 5 minutes, then discharged at a current of 0.1C with a cutoff voltage of 0.1V, then left to stand for 5 minutes before charging again. This charge-discharge cycle was repeated. The test results are shown in Table 1.

[0273] Table 1

[0274]

[0275] Note: The battery system of this invention undergoes a structural reorganization process in its early stages. This manifests in the battery performance as an activation process in the first few cycles, resulting in a relatively low initial capacity. Because the first few cycles are an activation process, the overall battery performance cannot be reflected in the first cycle. Capacity retention rate = Specific capacity after n cycles ÷ Specific capacity of the fifth cycle × 100% (for example, the 40th, 25th, and 21st cycles above correspond to n being 40, 25, or 21 respectively).

[0276] Meanwhile, see the cycle performance test graph of Example 2-1. Figure 19 As shown, Figures 20-22 The cycling performance test charts for Comparative Examples 2-1 to 2-3 are shown in sequence. It can be seen that the specific capacity of Example 2-1 decreased less after 40 cycles, while the specific capacity of Comparative Example 2-1 was not only lower at the beginning, but also dropped to close to 400 mAh / g after 25 cycles. The cycling performance of Comparative Example 2-2 was even worse, dropping to about 250 mAh / g after 21 cycles. The overall specific capacity of Comparative Example 2-3 was always insufficient.

[0277] As used throughout the specification and claims, the term "comprising" is an open-ended term and should be interpreted as "comprising but not limited to." "Substantially" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the product or system comprising said element.

[0278] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0279] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. An electrode tab, characterized by, The electrode tab comprises a first unit and a second unit arranged in layers, the first unit comprises a first current collector provided with a first hole, the second unit comprises a second current collector, an active material layer and a third current collector arranged in layers, the second current collector is provided with a second hole, the third current collector is provided with a third hole, the aperture of the second hole and the aperture of the third hole are smaller than the aperture of the first hole, and the active material layer comprises diiron trioxide.

2. The electrode patch of claim 1, wherein, The first unit has m, m is greater than or equal to 2, and any adjacent two first units are provided with the second unit.

3. The electrode patch of claim 2, wherein, The second unit has n, m = n + 1; or, the second unit is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

4. The electrode panel of any one of claims 1-3, wherein, The first current collector and the second current collector and / or the first current collector and the third current collector form a containing cavity in communication with the outside, and the containing cavity has an opening towards the active material layer.

5. The electrode panel of any one of claims 1-3, wherein, The first current collector is further provided with a fluid channel in communication with the first hole, and the fluid channel can also be in communication with the second hole on the corresponding second current collector or the third hole on the corresponding third current collector.

6. The electrode patch of claim 5, wherein, The fluid channel has a plurality of, part or all of the fluid channels extend to the edge of the first current collector and can be in communication with the outside; and / or, The fluid channel has a plurality of, and at least part of them are in communication with each other, further, all of the plurality of fluid channels are in communication; and / or, The first hole has at least one side in communication with the fluid channel; and / or, The opposite two sides of the first current collector are both formed with the fluid channel, and at least one side of the opposite two sides faces the active material layer; and / or, The ratio of the depth of the fluid channel along the thickness direction of the first current collector to the width of the fluid channel is 1:0.5-12; and / or, The depth of the fluid channel along the thickness direction of the first current collector is greater than or equal to 0.1mm, further 0.2-3mm, and more further 0.5-1.5mm; and / or, The width of the fluid channel is 2-9mm, further 3-7mm.

7. The electrode patch of claim 1, wherein, The thickness of the active material layer is 100-3000μm; and / or, The second current collector and the third current collector are the same; and / or, The mesh number of the second hole and the mesh number of the third hole are respectively 100-1000 mesh, further 150-800 mesh, and more further 200-750 mesh; and / or, The aperture of the first hole is 1-20mm, further 4-12mm; and / or, The first hole has a plurality of, and the sum of the opening areas of each first hole accounts for 10%-70% of the corresponding opening plane area of the first current collector, further can be 10%-60%; and / or, The thickness of the first current collector is greater than the thickness of the second current collector and the thickness of the third current collector; further, the thickness of the first current collector is 5-30 times the thickness of the second current collector, and more further 10-20 times; and / or, The thickness of the first current collector is 1-7 mm, further 1-5 mm; and / or, Each of the first units and each of the second units are sequentially stacked in the same direction.

8. The electrode patch of claim 1, wherein, The surface of the first current collector is provided with a nickel-containing coating, further, the thickness of the nickel-containing coating is 5-20 μm, more further 6-18 μm, still further 7-15 μm; Alternatively, the surface of the first current collector is provided with a nickel-phosphorus coating, further, the weight content of phosphorus in the nickel-phosphorus coating is 5wt.%-20wt.%, more further 8wt.%-12wt.%; and / or, the thickness of the nickel-phosphorus coating is 5-20 μm, more further 6-18 μm, still further 7-15 μm.

9. The electrode patch of claim 1, wherein, The material of the first current collector, the second current collector and the third current collector respectively comprises a metal conductive material or a non-metal conductive material, further, the metal conductive material comprises stainless steel, nickel or its alloy, copper alloy or aluminum alloy, and the non-metal conductive material comprises conductive carbon material or conductive polymer material; and / or, The electrode tab further comprises a tab formed on the first current collector; when the first current collector has a plurality, the tabs of each of the first current collectors are connected together, further, connected together by welding and / or fasteners; and / or, The outer periphery of each of the first current collector, the second current collector and the third current collector is connected together, further, connected together by welding and / or fasteners; and / or, The hardness of the first current collector is greater than the hardness of the second current collector and the hardness of the third current collector respectively, and the second current collector and the third current collector can be deformed by bending respectively; and / or, The active material layer is prepared by the following method: Mixing and uniformly mixing each component of the active material layer to prepare an active material mixture; Pressing the active material mixture into an active material layer, or setting the active material mixture between the second current collector and the third current collector to integrally form the second unit to obtain the active material layer.

10. The electrode patch of claim 1, wherein, The second current collector and the third current collector are respectively provided with a connecting part, which can be connected to the first current collector.

11. The electrode patch of claim 10, wherein, The connecting part is located at the side edge of the corresponding second current collector or third current collector; and / or, The length direction of the connecting part is parallel to the length direction of the corresponding second current collector or third current collector; and / or, The connecting part is connected to the first current collector which is spaced from the active material layer; and / or, The width direction of the connecting part extends towards the side of the adjacent active material layer; and / or, The connecting part on the second current collector and the connecting part on the third current collector are located on opposite sides of the electrode tab; and / or, The second current collector and the third current collector independently comprise a current collector body and the connecting part, and the current collector body and the connecting part are integrally formed to constitute the corresponding second current collector or third current collector.

12. The electrode patch of claim 1, wherein, The active material layer comprises the ferric oxide, a conductive agent and a binder; further, in the active material layer, the conductive agent accounts for 10%-30%, the ferric oxide accounts for 60%-80%, and the binder accounts for 1%-15% in terms of mass percentage; still further, the conductive agent comprises a two-dimensional conductive material.

13. The electrode patch of claim 1, wherein, The active material layer comprises a rust electrode material, the rust electrode material comprising a two-dimensional conductive material, the ferric oxide loaded on the two-dimensional conductive material, and a zero-dimensional conductive material and a one-dimensional conductive material; wherein the two-dimensional conductive material forms a basic framework, the zero-dimensional conductive material and the one-dimensional conductive material form extension frameworks respectively, and the basic framework and the extension frameworks jointly constitute an interconnected framework, and the ferric oxide is distributed in the interconnected framework; Or, the active material layer comprises a rust electrode material, the rust electrode material comprising a two-dimensional conductive material, the ferric oxide loaded on the two-dimensional conductive material, and a zero-dimensional conductive material and a one-dimensional conductive material; Wherein, in the rust electrode material, the two-dimensional conductive material accounts for 10%-40% in terms of mass percentage, and the addition amount of the two-dimensional conductive material is 1.5 times or more of the addition amount of any one of the zero-dimensional conductive material and the one-dimensional conductive material.

14. The electrode patch of claim 13, wherein, The addition amount of the two-dimensional conductive material is 1.5-15 times of the addition amount of any one of the zero-dimensional conductive material and the one-dimensional conductive material; And / or, the zero-dimensional conductive material, the one-dimensional conductive material and the two-dimensional conductive material are all conductive carbon materials; And / or, the thickness of the two-dimensional conductive material is 1-300 nm, and the flake diameter is 0.5-20 μm; and / or, The aspect ratio of the one-dimensional conductive material is 100-3000; and / or, the particle size of the zero-dimensional conductive material is 10-500 nm; and / or, The ferric oxide exists in the form of ferric oxide particles, and the particle size of the ferric oxide particles is 10-1000 nm; and / or, In the rust electrode material, the mass ratio of the zero-dimensional conductive material, the one-dimensional conductive material and the two-dimensional conductive material is 1:0.1-10:1.5-40, further 1:0.2-2.8:3-15, and still further 1:0.4-2.5:3.5-9; and / or, In the rust electrode material, the two-dimensional conductive material accounts for 15%-40%, the one-dimensional conductive material accounts for 1%-10%, and the zero-dimensional conductive material accounts for 1%-10% in terms of mass percentage, and further, the total content of the one-dimensional conductive material and the zero-dimensional conductive material accounts for 5%-15%; and / or, The two-dimensional conductive material comprises graphene and / or carbon nanosheet; and / or, The one-dimensional conductive material comprises carbon nanofiber and / or carbon nanotube; and / or, The zero-dimensional conductive material comprises acetylene black particles; and / or, The active material layer further comprises 1%-10% of a binder in terms of mass percentage. ​ 15. A method of producing the electrode sheet according to any one of claims 1 to 14, characterized by, The manufacturing method includes: pressing the first unit and the second unit stacked with each other together, and edge sealing and fixing the outer peripheral side of each current collector.

16. A negative electrode for an air cell, characterized by comprising: The negative electrode comprises the electrode tab according to any one of claims 1-14.

17. A rust battery characterized by, The rust battery comprises a negative electrode, an air positive electrode and an electrolyte, and the negative electrode is the air battery negative electrode according to claim 16.

18. The rust battery of claim 17, wherein, When the first charging is performed, the reactions of the negative electrode and the positive electrode are as follows, respectively: Negative reaction: Fe2O3 + 3H2O + 2e - → 2Fe(OH)2 + 2OH - , Fe(OH)2 + 2e - → Fe + 2OH - ; Positive electrode reaction: 4OH - → O2 + 2H2O + 4e - .

19. A method of using the rust battery of any one of claims 17-18 for energy storage, wherein, The rust battery can be directly used for charging energy storage without being discharged in advance.

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