Layered two-dimensional positive electrode material for zinc-iodine battery as well as preparation method and application of layered two-dimensional positive electrode material

Abstract

The invention relates to the field of novel electrochemical batteries and new energy batteries. The invention relates to a cathode material, in particular to a layered two-dimensional cathode material for a zinc-iodine battery and a preparation method and application thereof. The layered two-dimensional positive electrode material comprises single-walled carbon nanotubes and / or cellulose nanofibers, and a functional material with a layered two-dimensional structure, the functional material is selected from one of MXene, few-layer graphite, MoS2 and WS2. By constructing the brand-new layered two-dimensional nanofluid channel positive electrode material, the prepared aqueous zinc-iodine battery has higher area capacity and cycle capacity retention ratio, and can stably work in a voltage interval of 0.6-1.8 V.

Description

Technical Field

[0001] This invention relates to the fields of novel electrochemical batteries and new energy batteries. More specifically, it relates to a layered two-dimensional cathode material for zinc-iodine batteries, its preparation method, and its applications. Background Technology

[0002] Aqueous zinc-ion rechargeable batteries possess advantages such as high safety performance, low raw material cost, and environmental friendliness, making them a strong contender for next-generation new energy batteries and an important pathway to achieving "new energy + energy storage" in support of the "dual-carbon" strategy. However, aqueous electrolytes have a lower voltage window, and the deposition and stripping of zinc are accompanied by side reactions such as passivation, corrosion, and hydrogen evolution, as well as dendrite growth caused by uneven zinc deposition, which can easily lead to problems such as battery capacity decay, low coulombic efficiency, and limited lifespan. Utilizing the redox process of halogen elements such as iodine to store and release energy is another feasible approach. Due to its wide availability, low cost, environmental friendliness, and the fact that it involves a multi-electron transfer reaction with highly reversible redox processes, it has been extensively studied as a cathode material for aqueous zinc-ion batteries in recent years. However, several key issues regarding iodine conversion, such as slow reaction kinetics, polyiodide shuttle effect, low energy density, and the instability of the zinc anode, still exist, significantly hindering its practical application. Therefore, developing more efficient and stable cathode materials that can effectively address the polyiodide shuttle effect and other related problems is particularly important. Improving the structural design of cathode materials and optimizing the conversion efficiency and stability of iodides will be a key path to improving the performance of Zn-I2 batteries. In recent years, research on zinc-iodine batteries has gradually increased, especially in the development of cathode materials with high specific capacity and long lifespan, with significant progress mainly focused on carbon-based materials, metal compounds, organic materials, and conductive polymers. However, most laboratory-scale advancements have been achieved with relatively low iodine loading, resulting in relatively low areal capacity and energy density, far below the standards for practical applications. Summary of the Invention

[0003] Based on the above-mentioned shortcomings, the first objective of this invention is to provide a layered two-dimensional cathode material for zinc-iodine batteries.

[0004] A second objective of this invention is to provide a method for preparing the layered two-dimensional cathode material for zinc-iodine batteries as described above.

[0005] A third objective of this invention is to provide an application of the layered two-dimensional cathode material described above in the preparation of zinc-iodine batteries.

[0006] A fourth objective of this invention is to provide a zinc-iodine battery comprising the layered two-dimensional cathode material as described above.

[0007] To achieve the first objective mentioned above, the present invention adopts the following technical solution: This invention discloses a layered two-dimensional cathode material for zinc-iodine batteries, comprising single-walled carbon nanotubes and / or cellulose nanofibers, as well as a functional material having a layered two-dimensional structure; The functional material is selected from one of MXene, few-layer graphite, MoS2, and WS2. Few-layer graphite is a material composed of 3-10 layers of carbon atoms arranged in sp... 2 Two-dimensional carbon nanomaterials with hexagonal honeycomb lattice composed of hybrid orbitals.

[0008] To address the shortcomings of existing technologies, this invention proposes a novel layered two-dimensional nanofluidic channel cathode material to solve problems such as zinc anode dendrite growth and positive electrode polyiodide shuttling in aqueous zinc-iodine batteries. The aim is to construct batteries with high capacity, high coulombic efficiency, and long cycle life. By introducing functional materials with layered two-dimensional structures (such as MXene, few-layer graphite, MoS2, WS2, etc.) into the layered two-dimensional cathode material, stable charge-discharge reactions at both the positive and negative electrodes can be achieved, with low raw material costs and simple battery assembly steps.

[0009] Furthermore, the layered two-dimensional cathode material includes single-walled carbon nanotubes and functional materials with a layered two-dimensional structure. The carbon nanotubes can construct more conductive pathways between the layers, promoting ion and electron transport. In one specific embodiment, the mass ratio of single-walled carbon nanotubes to functional materials is 1:9 to 1:19; exemplaryly, the mass ratio of single-walled carbon nanotubes to functional materials can be 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, etc.

[0010] Furthermore, the layered two-dimensional cathode material includes cellulose nanofibers and functional materials with a layered two-dimensional structure. Cellulose nanofibers can enhance the mechanical flexibility of the membrane electrode and expand the interlayer spacing, making the entire two-dimensional nanofluid structure more stable. In one specific embodiment, the mass ratio of cellulose nanofibers to functional materials is 1:4-1:19; exemplaryly, the mass ratio of cellulose nanofibers to functional materials can be 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, etc.

[0011] Furthermore, the layered two-dimensional cathode material includes single-walled carbon nanotubes, cellulose nanofibers, and functional materials with a layered two-dimensional structure. The mass ratio of single-walled carbon nanotubes, cellulose nanofibers, and functional materials ranges from 1:4:15 to 1:1:18, preferably 1:1:18.

[0012] Furthermore, the thickness of the layered two-dimensional cathode material is 15-25 μm, and the interlayer spacing of the functional materials is 0.8-1.0 nm.

[0013] To achieve the second objective mentioned above, the present invention adopts the following technical solution: This invention discloses a method for preparing the layered two-dimensional cathode material as described above, comprising the following steps: The functional material is dispersed in an ultra-dry organic solvent or deionized water, sonicated, and single-walled carbon nanotubes and / or cellulose nanofibers are selectively added, sonicated, and filtered to obtain the layered two-dimensional cathode material.

[0014] Furthermore, the ultra-dry organic solvent is selected from N-methylpyrrolidone and / or ethanol.

[0015] To achieve the third objective mentioned above, the present invention adopts the following technical solution: This invention discloses the application of the layered two-dimensional cathode material described above in the preparation of zinc-iodine batteries.

[0016] To achieve the fourth objective mentioned above, the present invention adopts the following technical solution: This invention discloses a zinc-iodine battery, the zinc-iodine battery comprising: The layered two-dimensional cathode material described above is used as the cathode material; Zinc sheet as a negative electrode material; and Iodine-containing electrolyte.

[0017] Furthermore, the iodine-containing electrolyte is a mixture containing 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide.

[0018] Furthermore, the zinc-iodine battery is assembled according to the following steps: a spring sheet, a gasket, a zinc negative electrode, a separator, an electrolyte, and the above-mentioned layered two-dimensional positive electrode material are sequentially added to the negative electrode shell of the battery, and then the positive electrode battery shell is attached to assemble it into a button battery.

[0019] Furthermore, the zinc negative electrode is selected from one of zinc foil, zinc plate, zinc sheet, zinc powder, electroplated zinc, zinc foam, and zinc alloy.

[0020] Furthermore, the diaphragm is selected from one of ordinary filter paper, aqueous filter paper, and glass fiber filter paper.

[0021] Furthermore, the electrolyte is at least one of zinc sulfate, zinc trifluoromethanesulfonate, and 1-methyl-3-propylimidazolium iodide, and contains at least 1-methyl-3-propylimidazolium iodide.

[0022] The beneficial effects of this invention are as follows: This invention constructs a novel layered two-dimensional nanofluidic channel cathode material, which, on the one hand, accelerates ion transport efficiency and improves battery reaction kinetics while ensuring conductivity; on the other hand, the cathode has the effect of suppressing the shuttle effect of polyiodine species, which can make the battery have better cycle stability.

[0023] The cathode material prepared by this invention has multiple functions, including mitigating dendrite growth, inhibiting corrosion, and preventing hydrogen evolution, which can significantly improve the cycle life and coulombic efficiency of rechargeable secondary zinc batteries under high current density.

[0024] The raw materials for preparing the cathode material according to this invention are widely available and inexpensive. The preparation method is simple, has a short cycle, is environmentally friendly, and is easy to mass-produce. Attached Figure Description

[0025] Figure 1 The diagram shows test results of batteries prepared based on the cathode materials of Example 1 and Comparative Example 1, including charge-discharge and cycle tests.

[0026] Figure 2 Electron micrographs show the zinc sheet corrosion after 1000 battery cycles of the cathode materials based on Example 1 and Comparative Example 1. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Example 1 Preparation of layered two-dimensional cathode material: Weigh 90mg of few-layer graphite solid, disperse it in 50ml of ultra-dry N-methylpyrrolidone, sonicate at room temperature for 1h, sonicate to break it up for 2min, add 5mg of cellulose nanofibers and 5mg of single-walled carbon nanotubes, sonicate at room temperature for 1h, and vacuum filter to obtain membrane material.

[0029] Preparation of zinc-iodine batteries: A spring sheet, a gasket, a zinc sheet, ordinary filter paper, 70 μL of electrolyte (containing 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide electrolyte) and the above-mentioned layered two-dimensional positive electrode material were added sequentially to the negative electrode shell of the battery. The positive electrode battery shell was then attached to assemble the battery into a button cell, and the electrochemical performance was tested.

[0030] At a temperature of 25°C and a current density of 0.5 mA cm⁻¹ -2 Performance tests were conducted under a voltage range of 0.6-1.8 V, such as... Figure 1 As shown, this battery can achieve a power output of up to 0.9893 mAh cm⁻¹. -2 It has a large area capacity and retains 98% of its capacity after nearly 4000 hours of cycling.

[0031] Subsequently, the temperature was maintained at a constant 25°C, and the current density was 1 mA cm⁻¹. -2 After 1000 cycles under a voltage range of 0.6-1.8 V, the SEM image of the zinc sheet clearly shows a relatively smooth surface and minimal corrosion (see [link to SEM image]). Figure 2 This indicates that the obtained zinc-iodine full cell can operate stably within the voltage range of 0.6-1.8V, and has a long cycle life and high areal capacity.

[0032] Comparative Example 1 Preparation of layered two-dimensional cathode material: Weigh 100mg of few-layer graphite solid, disperse it in 50ml of ultra-dry N-methylpyrrolidone, sonicate at room temperature for 1h, sonicate to break it up for 2min, and then vacuum filter to obtain the membrane material.

[0033] Preparation of zinc-iodine batteries: A spring, a gasket, a zinc sheet, ordinary filter paper, 70 μL of 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide electrolyte, and the above positive electrode materials were sequentially added to the negative electrode shell of the battery. The positive electrode battery shell was then attached to assemble the battery into a button cell, and the electrochemical performance was tested.

[0034] At a temperature of 25°C and a current density of 0.5 mA cm⁻¹ -2 Performance tests were conducted under a voltage range of 0.6-1.8 V, such as... Figure 1 As shown, compared with the battery assembled from the layered two-dimensional nanofluidic channel cathode material constructed in this invention, it has a lower areal capacity (0.7051 mAh cm⁻¹). -2 ), and the capacity retention rate was 72.2% after 500 laps.

[0035] Subsequently, the temperature was maintained at a constant 25°C, and the current density was 1 mA cm⁻¹. -2 After 1000 cycles under a voltage range of 0.6-1.8 V, the zinc sheet corrosion was as follows. Figure 2As shown, the zinc sheet surface corrodes after charge-discharge cycles, generating irregular byproducts that severely affect battery life.

[0036] Comparative Example 2 Preparation of layered two-dimensional cathode material: Weigh 95mg of few-layer graphite solid, disperse it in 50ml of ultra-dry N-methylpyrrolidone organic solution, sonicate at room temperature for 1h, sonicate to break it up for 2min, add 5mg of cellulose nanofibers, sonicate at room temperature for 1h, and vacuum filter to obtain membrane material.

[0037] Preparation of zinc-iodine batteries: A spring, a gasket, a zinc sheet, ordinary filter paper, 70 μL of 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide electrolyte, and the above positive electrode materials were sequentially added to the negative electrode shell of the battery. The positive electrode battery shell was then attached to assemble the battery into a button cell, and the electrochemical performance was tested.

[0038] The test results were similar to those of Comparative Example 1, indicating that the performance of the obtained zinc-iodine full cell was low in the voltage range of 0.6-1.8V.

[0039] Comparative Example 3 Preparation of layered two-dimensional cathode material: Weigh 95mg of few-layer graphite solid, disperse it in 50ml of ultra-dry N-methylpyrrolidone organic solution, sonicate at room temperature for 1h, sonicate to break up for 2min, add 5mg of single-walled carbon nanotubes, sonicate at room temperature for 1h, and vacuum filter to obtain membrane material.

[0040] Preparation of zinc-iodine batteries: A spring, a gasket, a zinc sheet, ordinary filter paper, 70 μL of 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide electrolyte, and the above positive electrode materials were sequentially added to the negative electrode shell of the battery. The positive electrode battery shell was then attached to assemble the battery into a button cell, and the electrochemical performance was tested.

[0041] The test results were similar to those of Comparative Example 1, indicating that the performance of the obtained zinc-iodine full cell was low in the voltage range of 0.6-1.8V.

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A layered two-dimensional cathode material for zinc-iodine batteries, characterized in that, Including single-walled carbon nanotubes and / or cellulose nanofibers, as well as functional materials with layered two-dimensional structures; The functional material is selected from one of MXene, few-layer graphite, MoS2, and WS2.

2. The layered two-dimensional cathode material according to claim 1, characterized in that, The layered two-dimensional cathode material includes single-walled carbon nanotubes and functional materials with a layered two-dimensional structure, with a mass ratio of single-walled carbon nanotubes to functional materials of 1:9-1:

19.

3. The layered two-dimensional cathode material according to claim 1, characterized in that, The layered two-dimensional cathode material includes cellulose nanofibers and functional materials with a layered two-dimensional structure, with a mass ratio of cellulose nanofibers to functional materials of 1:4 to 1:

19.

4. The layered two-dimensional cathode material according to claim 1, characterized in that, The layered two-dimensional cathode material includes single-walled carbon nanotubes, cellulose nanofibers, and functional materials with a layered two-dimensional structure, with the mass ratio of single-walled carbon nanotubes, cellulose nanofibers, and functional materials being 1:4:15-1:1:

18.

5. The layered two-dimensional cathode material according to claim 1, characterized in that, The thickness of the layered two-dimensional cathode material is 15-25 μm, and the interlayer spacing of the functional materials is 0.8-1.0 nm.

6. The method for preparing the layered two-dimensional cathode material according to any one of claims 1-5, characterized in that, Includes the following steps: The functional material is dispersed in an ultra-dry organic solvent or deionized water, sonicated, and single-walled carbon nanotubes and / or cellulose nanofibers are selectively added, sonicated, and filtered to obtain the layered two-dimensional cathode material.

7. The preparation method according to claim 6, characterized in that, The ultra-dry organic solvent is selected from N-methylpyrrolidone and / or ethanol.

8. The application of the layered two-dimensional cathode material as described in any one of claims 1-5 in the preparation of zinc-iodine batteries.

9. A zinc-iodine battery, characterized in that, include The layered two-dimensional cathode material according to any one of claims 1-5 is used as the cathode material; Zinc sheet as a negative electrode material; and Iodine-containing electrolyte.

10. The zinc-iodine battery according to claim 9, characterized in that, The iodine-containing electrolyte is a mixture containing 2M zinc trifluoromethanesulfonate and 1M 1-methyl-3-propylimidazolium iodide.

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