A zinc-iodine battery positive electrode binder, a zinc-iodine battery positive electrode sheet based on the binder, and a preparation method and application thereof
By using sodium lignin sulfonate binder in the positive electrode of zinc-iodine batteries to adsorb polyiodides, the problem of negative electrode corrosion caused by polyiodide shuttling in zinc-iodine batteries was solved, high stability and long-life battery performance were achieved, costs were reduced and the process was simplified.
Patent Information
- Application Number
- CN202411984684.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2044-12-31
AI Technical Summary
In existing aqueous zinc-iodine batteries, the conversion process between elemental iodine and iodine anions in the positive electrode easily forms polyiodides, leading to corrosion of the negative electrode. The existing strategies are complex and costly.
Sodium lignin sulfonate is used as a binder, and through the action of its polar groups and sulfonate ions, it adsorbs the shuttle behavior of polyiodide compounds, inhibits the shuttle of polyiodide compounds, and reduces their generation in the battery.
The zinc-iodine battery has high stability, high rate performance and long cycle life, which reduces costs, simplifies the preparation process and is environmentally friendly.
Smart Images
Figure CN119812334B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of battery binder materials, and in particular to a zinc-iodine battery positive electrode binder, a zinc-iodine battery positive electrode sheet based on the binder, and a preparation method and application thereof. Background Art
[0002] Lithium-ion batteries are widely used in electric vehicles, aviation crafts and portable electronic products, and have occupied most of the market in recent decades. However, the scarce resources and high cost of lithium as well as flammable and toxic organic electrolytes have greatly hindered their application and are unable to adapt to the development of the new energy era. Compared with lithium-ion batteries, aqueous zinc-iodine batteries are becoming a promising alternative due to their abundant resources, cost-effectiveness, safety and environmental friendliness. The aqueous electrolyte in zinc-iodine batteries is non-toxic and non-flammable, and has excellent ion conduction and diffusion capabilities, thereby improving the reaction kinetics. However, due to the slow dissolution of iodine in the positive electrode and the slow conversion kinetics of iodine, polyiodides (I3 - 、I5 - ......), polyiodides can freely shuttle to the negative electrode, react with the negative electrode, generate by-products, and cause negative electrode corrosion.
[0003] In response to these problems, people have proposed different solutions, such as building an in-situ or non-in-situ protective layer on the zinc negative electrode to repel polyiodides, avoid their mutual contact, and reduce the corrosion of the zinc negative electrode. - ) electrolyte, using (OTf) - The oxidative effect of iodide ions is used to oxidize and expel them, thereby inhibiting their shuttle. At the positive electrode, porous catalytically active materials are used to immobilize iodine, reducing iodine dissolution during battery cycling and thus reducing the production of polyiodides. However, these strategies are cumbersome and complex in operation, leading to increased costs. Another simpler method is to add a binder that can absorb polyiodides to the positive electrode. While achieving the same polyiodide inhibition effect as the above three methods, it is less expensive. Summary of the Invention
[0004] In view of this, the present application provides a zinc-iodine battery positive electrode binder with functional groups, a zinc-iodine battery positive electrode sheet based on the binder, and a preparation method and application thereof. Adding a binder capable of adsorbing polyiodides to the battery positive electrode can not only bond the active material and the conductive agent to the current collector to improve stability, but also inhibit the behavior of polyiodide shuttling, so that the aqueous zinc-iodine battery can obtain high stability, high rate performance and long cycle life. The process of the present application is simple, the cost is lower and it is environmentally friendly, and it can effectively overcome the serious polyiodide shuttling problem existing in existing aqueous zinc-iodine batteries.
[0005] In a first aspect, the present application provides a positive electrode binder for zinc-iodine batteries, wherein the binder is sodium lignin sulfonate.
[0006] The present application provides a binder with lower cost and better high-temperature performance. The binder is preferably sodium lignin sulfonate, which is brown in color and is the product of lignin sulfonation. Lignin is second only to cellulose in production and is inexpensive.
[0007] The second aspect of the present application further provides a method for preparing a zinc-iodine battery positive electrode sheet based on a binder, using the above-mentioned battery positive electrode binder, comprising the following steps:
[0008] The active material, conductive agent and binder are dissolved in water in a certain proportion and mixed evenly to obtain a black paste slurry; the black paste slurry is evenly applied on the current collector and dried naturally in the air to obtain the positive electrode of the battery.
[0009] Specifically, the present invention uniformly disperses sodium lignin sulfonate in the positive electrode. Sodium lignin sulfonate contains a large number of polar groups (-OH, COC), which are easy to obtain electrons, have electrophilicity, and have an adsorption effect on polyiodide and iodine; sulfonate ions are easy to give electrons, have nucleophilicity, and have an adsorption effect on I - It has a certain repulsive effect, avoiding the I - The contact with I2 in the positive electrode reduces the generation of polyiodide, thereby achieving double inhibition of polyiodide shuttling.
[0010] Preferably, the active substance is elemental iodine.
[0011] Preferably, the active material is prepared by mixing ultra-high capacity activated carbon and elemental iodine in a mass ratio of 1:1, and calcining the mixture to form the active material.
[0012] Preferably, the calcination temperature is 120° C. and the calcination time is 6 hours.
[0013] Preferably, the mass of the binder accounts for 5-15% of the total mass of the positive electrode sheet excluding the current collector (i.e. excluding the mass of the stainless steel mesh); or
[0014] The mass of the binder accounts for 10% of the total mass of the positive electrode sheet excluding the current collector (i.e. excluding the mass of the stainless steel mesh); or
[0015] The mass ratio of the active material, conductive agent, and binder is 7:(2-2.5):(0.5-1.5). Specifically, the mass of the binder accounts for 5%, 10%, and 15% of the total mass of the positive electrode sheet excluding the current collector (excluding the mass of the stainless steel mesh), with the optimal mass ratio being 10%.
[0016] Preferably, the conductive agent is Ketjen black.
[0017] Preferably, the current collector is a stainless steel mesh.
[0018] The third aspect of the present application also provides a zinc-iodine battery positive electrode sheet, which is a zinc-iodine battery positive electrode sheet prepared by the above method.
[0019] The fourth aspect of the present application further provides a zinc-iodine battery, which is assembled into a button-type zinc-iodine battery by combining a zinc sheet negative electrode, a separator, a 2M zinc salt electrolyte, the above-mentioned positive electrode sheet and a battery shell;
[0020] The zinc salt is selected from zinc sulfate, zinc acetate, zinc nitrate and zinc chloride.
[0021] Specifically, the zinc salt is zinc sulfate.
[0022] Compared with the prior art, this application has the following beneficial effects:
[0023] (1) The present application provides a binder with lower cost and better high temperature performance. The binder is preferably sodium lignin sulfonate, which is brown in color and is the product of lignin sulfonation. The process flow is simple. The output of lignin is second only to cellulose, the largest output, and the price is low and the output is abundant.
[0024] (2) The sodium lignin sulfonate of the present application has both electrostatic repulsion to repel polyiodides and inhibit shuttling; and electrostatic attraction to absorb polyiodides and reduce the concentration of polyiodides.
[0025] (3) The present application utilizes sodium lignin sulfonate as the positive electrode binder of aqueous zinc-iodine batteries to reduce the corrosion of the zinc negative electrode by polyiodide, extend the battery life, and improve the initial capacity and cycle stability of the battery.
[0026] (4) The preparation process of this application is simple, the raw materials are abundant, and the cost is low. The raw materials are green and degradable materials. It shows great application potential in the field of promoting the development of zinc-iodine batteries towards high stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the description of the present application or the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0028] Figure 1 This is a comparison of the cycling performance of zinc-iodine full batteries assembled with the sodium lignin sulfonate binder in Example 1 of the present application and the lignin in Comparative Example 1 at 50° C. and a current density of 0.5 A / g;
[0029] Figure 2 This is a comparison chart of the UV-visible adsorption intensity of the supernatant of the positive electrode sheet loaded with sodium lignin sulfonate in Example 1 of the present application and the positive electrode sheet loaded with lignin in Comparative Example 1, each of which was immersed in I- solution;
[0030] Figure 3 The sodium lignin sulfonate powder in Example 1 of the present application is soaked in water containing I3 - XPS graph of the precipitate in solution after drying;
[0031] Figure 4 This is a SEM comparison of zinc sheets of the zinc-iodine battery assembled in Example 1 of the present application and the zinc-iodine battery assembled in Comparative Example 1 after 20 charge and discharge cycles at a current density of 1 A / g;
[0032] Figure 5 This is a comparison chart of the XRD patterns of the zinc sheets of the zinc-iodine battery assembled in Example 1 of the present application and the zinc-iodine battery assembled in Comparative Example 1 after 20 charge and discharge cycles at a current density of 1 A / g. DETAILED DESCRIPTION
[0033] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0034] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.
[0035] In the following examples and comparative examples, unless otherwise specified, all raw materials can be purchased commercially or prepared by conventional methods.
[0036] Example 1
[0037] First, ultra-high capacity activated carbon and elemental iodine were mixed in a mass ratio of 1:1 and calcined at a temperature of 120°C for 6 hours to form an active substance.
[0038] Secondly, the active material, conductive agent Ketjen black, and sodium lignin sulfonate are evenly mixed in a mass ratio of 7:2:1, a small amount of water is added to stir into a slurry, and the slurry is evenly scraped onto a circular stainless steel mesh with a diameter of 12 mm. It is naturally dried in the air to obtain a positive electrode sheet.
[0039] Then, zinc sulfate was dissolved in deionized water to prepare a 2M zinc sulfate electrolyte.
[0040] Finally, a 12mm round zinc sheet was used as the negative electrode, glass fiber as the separator, 2M zinc sulfate as the electrolyte, a plate containing 10% sodium lignin sulfonate binder as the positive electrode, and 2025 model positive and negative battery shells were assembled into a button-type zinc-iodine battery.
[0041] The prepared battery has a high reversible capacity of 152.8 mAh / g and a high capacity retention rate of 82.2% after 500 cycles at a current density of 0.5 A / g and a 50°C environment. In contrast, the corresponding capacity of the battery using the lignin binder is only 120.2 mAh / g ( Figure 1 ).
[0042] The electrode containing sodium lignin sulfonate (LS) in Example 1 and the electrode containing lignin (DL) in Comparative Example 1 were added to 0.1 MI - The solution was allowed to stand for three days, and the supernatant was taken to measure the UV spectrum. The I3 - The concentration was lower than that of control group ( Figure 2 ).
[0043] The sodium lignin sulfonate powder (LS) in Example 1 was added to the mixture containing I3 - The solution was left to stand for one day, and the bottom precipitate was dried and XPS was measured. I3 was detected in the sodium lignin sulfonate powder. - , indicating that sodium lignin sulfonate has a certain adsorption effect on polyiodide ( Figure 3 ).
[0044] After the battery assembled in Example 1 and the battery assembled in Comparative Example 1 were charged and discharged for 20 cycles at a current density of 1 A / g, the surfaces of the zinc negative electrodes of the two batteries were examined by SEM ( Figure 4 ) and XRD( Figure 5 ) test, the zinc negative electrode of the battery assembled with sodium lignin sulfonate (LS) as a binder was smoother and produced less by-products (Zn4SO4(OH)6·5H2O) after 20 cycles.
[0045] Example 2
[0046] First, ultra-high capacity activated carbon and elemental iodine were mixed in a mass ratio of 1:1 and calcined at a temperature of 120°C for 6 hours to form an active substance.
[0047] Secondly, the active material, conductive agent Ketjen black, and sodium lignin sulfonate are evenly mixed in a mass ratio of 7:2.5:0.5, a small amount of water is added to stir into a slurry, and the slurry is evenly scraped onto a circular stainless steel mesh with a diameter of 12 mm. It is naturally dried in the air to obtain a positive electrode.
[0048] Then, zinc sulfate was dissolved in deionized water to prepare a 2M zinc sulfate electrolyte.
[0049] Finally, a 12mm round zinc sheet was used as the negative electrode, glass fiber as the separator, 2M zinc sulfate as the electrolyte, a plate containing 5% sodium lignin sulfonate binder as the positive electrode, and 2025 model positive and negative battery shells were assembled into a button-type zinc-iodine battery.
[0050] The prepared battery had a capacity of 142.8 mAh / g and a capacity retention rate of 72.8% after 100 cycles of the battery using sodium lignin sulfonate binder at a current density of 0.1 A / g.
[0051] Example 3
[0052] First, ultra-high capacity activated carbon and elemental iodine were mixed in a mass ratio of 1:1 and calcined at a temperature of 120°C for 6 hours to form an active substance.
[0053] Secondly, the active material, conductive agent Ketjen black, and sodium lignin sulfonate are evenly mixed in a mass ratio of 7:1.5:1.5, a small amount of water is added to stir into a slurry, and the slurry is evenly scraped onto a circular stainless steel mesh with a diameter of 12 mm. It is naturally dried in the air to obtain a positive electrode sheet.
[0054] Then, zinc sulfate was dissolved in deionized water to prepare a 2M zinc sulfate electrolyte.
[0055] Finally, a button-type zinc-iodine battery was assembled using a 12mm round zinc sheet as the negative electrode, a glass fiber separator, a 2M zinc sulfate electrolyte, a 15% sodium lignin sulfonate binder as the positive electrode, and 2025-size positive and negative battery cases. The prepared battery, using the sodium lignin sulfonate binder, exhibited a capacity of 144.4 mAh / g and a capacity retention of 74.6% after 100 cycles at a current density of 0.1 A / g.
[0056] Comparative Example 1
[0057] First, ultra-high capacity activated carbon and elemental iodine were mixed in a mass ratio of 1:1 and calcined at a temperature of 120°C for 6 hours to form an active substance.
[0058] Secondly, the active material, conductive agent Ketjen black and lignin are evenly mixed in a mass ratio of 7:2:1, a small amount of water is added to stir into a slurry, and the slurry is evenly scraped onto a circular stainless steel mesh with a diameter of 12 mm. It is naturally dried in the air to obtain a positive electrode.
[0059] Then, zinc sulfate was dissolved in deionized water to prepare a 2M zinc sulfate electrolyte.
[0060] Finally, a 12mm round zinc sheet was used as the negative electrode, glass fiber as the separator, 2M zinc sulfate as the electrolyte, a plate containing 10% lignin binder as the positive electrode, and 2025 model positive and negative battery shells were assembled into a button-type zinc-iodine battery.
[0061] The prepared battery has a reversible capacity of 120.2 mAh / g after 500 cycles at 50°C and 0.5 A / g current density.
[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder, characterized in that: The following steps are involved: The active material, conductive agent and binder are dissolved in water in a certain proportion and mixed evenly to obtain a black paste slurry; the black paste slurry is evenly applied on the current collector and dried naturally in the air to obtain the positive electrode sheet of the battery; The binder is sodium lignin sulfonate; the preparation process of the active substance is: mixing ultra-high capacity activated carbon with elemental iodine, and calcining to form the active substance.
2. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 1, characterized in that: The mass ratio of the ultra-high capacity activated carbon to elemental iodine is 1:
1.
3. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 1, wherein: The calcination temperature is 120° C. and the calcination time is 6 hours.
4. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 1, wherein: The mass of the binder accounts for 5-15% of the total mass of the positive electrode sheet excluding the current collector; or The mass ratio of the active material, the conductive agent and the binder is 7:(1.5-2.5):(0.5-1.5).
5. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 4, characterized in that: The mass of the binder accounts for 10% of the total mass of the positive electrode sheet excluding the current collector.
6. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 1, characterized in that: The conductive agent is Ketjen black.
7. The method for preparing a positive electrode sheet for a zinc-iodine battery based on a binder according to claim 1, characterized in that: The current collector is a stainless steel mesh.
8. A zinc-iodine battery positive electrode plate, characterized in that: A zinc-iodine battery positive electrode sheet prepared by the method according to any one of claims 1 to 7.
9. A zinc-iodine battery, characterized in that: A button-type zinc-iodine battery is assembled from a zinc sheet negative electrode, a separator, a 2M zinc salt electrolyte, the positive electrode sheet according to claim 8, and a battery shell; The zinc salt is selected from zinc sulfate, zinc acetate, zinc nitrate and zinc chloride.