A battery with iodine-based four-electron transfer catalyzed by molybdenum-boron soft and hard Lewis acids
Through the molybdenum boron soft and hard Lewis acid synergistic catalyst in the four-electron transfer iodine-based battery, the Lewis acid-base theory is used to promote iodine ion transfer, which solves the problem of poor stability and circulation performance of the battery in an aqueous environment, and improves the efficiency of the battery and capacity.
Patent Information
- Application Number
- CN202411353968.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2044-09-27
AI Technical Summary
Four-electron transfer iodine-based batteries are susceptible to hydrolysis during the electrooxidation of iodine, resulting in poor reversibility, poor stability and cycling performance of zinc negative electrodes in aqueous electrolytes, low Coulomb efficiency, insufficient electrochemical stability and capacity.
Molybdenum boron soft and hard Lewis acid synergistic catalyst was introduced, and through the Lewis acid-base theory coordination principles, the coordinated catalysis of promoting complete four-electron transfer of iodine ions is improved, and the reaction kinetics and electrodes are improved. The capacity of the material.
It improves the Coulomb efficiency, electrochemical stability and capacity of the battery, increases the energy density, and extends the cycle life of the battery.
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Figure CN118888872B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of battery preparation, and in particular to a battery in which molybdenum-boron soft and hard Lewis acids synergistically catalyze iodine-based four-electron transfer. Background Art
[0002] As climate change and environmental pollution become more and more serious, especially in recent years, with the development of science and technology, various electronic products such as smartphones and laptops have higher and higher requirements for energy storage. The growing demand for efficient and sustainable energy storage systems has promoted the exploration of advanced battery technologies other than lithium-ion batteries, making aqueous zinc-ion batteries a focus of attention in the field of energy storage.
[0003] As the negative electrode of zinc-based batteries, metallic zinc has low potential, abundant reserves, and is green and non-toxic. These advantages make the development of aqueous zinc-ion batteries a general trend and a potential candidate for large-scale energy storage. Compared with strong acid lead-acid batteries and strong alkaline nickel-hydrogen batteries, zinc-based batteries mostly use mild weak acid or neutral electrolytes, which greatly reduces the corrosion resistance requirements for battery components such as current collectors and shells. Among various aqueous zinc-ion battery configurations, rechargeable Zn-I2 aqueous solution batteries have attracted great attention due to the electrochemical adjustability of iodine with rich valence states.
[0004] Compared with the conventional double electron transfer iodine battery (I - / I2) compared to the continuous redox pair (I - / I2 / ICl) has a higher redox potential and theoretical specific capacity. Nevertheless, the development of four-electron transfer iodine-based batteries is still in its early stages and faces major challenges that affect stability and long-term performance. + It will be subjected to nucleophilic attack by the OH part of water, resulting in hydrolysis, which makes the reversibility of four-electron transfer worse. At the same time, the stable cycle of zinc anode in aqueous electrolyte faces challenges such as hydrogen evolution, surface corrosion and dendrite formation, which will exhaust the electrolysis during long-term cycling. These together lead to iodine-based four-electron transfer batteries with low coulombic efficiency, poor electrochemical stability, and low battery capacity. Therefore, a new type of four-electron transfer iodine-based battery is needed to solve the above problems. Summary of the invention
[0005] In view of the above-mentioned prior art, the purpose of the present invention is to provide a battery that uses molybdenum-boron soft and hard Lewis acids to synergistically catalyze iodine-based four-electron transfer. The present invention introduces boron (hard Lewis acid) and molybdenum (soft Lewis acid), and according to the Lewis acid-base theory "hard acid-hard base" and "soft acid-soft base" combination principle, synergistic catalysis promotes the complete four-electron transfer of iodine ions and improves the reaction kinetics.
[0006] To achieve the above object, the present invention adopts the following technical solution:
[0007] In a first aspect of the present invention, a battery for iodine-based four-electron transfer catalyzed by molybdenum-boron soft and hard Lewis acids is provided, wherein the battery comprises a positive electrode, a negative electrode and an electrolyte; the positive electrode comprises a positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids; the negative electrode is a metal zinc foil; and the electrolyte is a solution containing zinc ions;
[0008] The positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids is prepared by the following method:
[0009] (1) mixing a boron source, a molybdenum source and activated carbon, and calcining them under an inert atmosphere to obtain a molybdenum-boron soft and hard Lewis acid synergistic catalyst;
[0010] (2) The molybdenum-boron soft and hard Lewis acid synergistic catalyst is mixed with iodine and ground, and then subjected to heat treatment to obtain a positive electrode material synergistically catalyzed by molybdenum-boron soft and hard Lewis acid.
[0011] Preferably, in step (1), the boron source is borax; and the molybdenum source is molybdenum nitrate.
[0012] Preferably, in step (1), the mass ratio of the boron source, the molybdenum source and the activated carbon is 7:10:20; the mixing method includes adsorption method, coprecipitation method, hydrolysis method, hydrothermal method or grinding mixing method.
[0013] Preferably, in step (1), the calcination temperature is 800-1200° C., the calcination time is 2-8 hours, and the calcination heating rate is 5° C. / min.
[0014] Preferably, in step (2), the mass ratio of the molybdenum-boron soft and hard Lewis acid synergistic catalyst to iodine is 1:1-4.
[0015] Preferably, in step (2), the heating treatment temperature is 90-120° C., and the heating treatment time is 6-10 h.
[0016] Preferably, the positive electrode is obtained by coating a mixed positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids, a conductive agent and a positive electrode material binder.
[0017] Preferably, the positive electrode material binder is sodium carboxymethyl cellulose; the conductive agent is conductive carbon; and the mass ratio of the positive electrode material catalyzed by the molybdenum-boron soft and hard Lewis acid, the conductive agent and the positive electrode material binder is 8:1:1.
[0018] Preferably, the loading amount of the positive electrode material catalyzed by the soft and hard Lewis acids of molybdenum and boron in the positive electrode is 1-2 mg·cm -2 .
[0019] The second aspect of the present invention provides the use of the above-mentioned battery in improving the coulombic efficiency, electrochemical stability and capacity of aqueous batteries.
[0020] Beneficial effects of the present invention:
[0021] (1) The present invention starts from Lewis acid-base theory and solves the problem of slow kinetics of iodine-based electrochemical reactions from the perspective of designing a coordination intermediate. The idea is clear and theoretically innovative.
[0022] (2) The present invention introduces boron (hard Lewis acid) and molybdenum (soft Lewis acid) to synergistically catalyze and promote the complete four-electron transfer of iodide ions, thereby improving the reaction kinetics, based on the "hard acid-hard base" and "soft acid-soft base" combination principles of Lewis acid-base theory.
[0023] (3) The present invention targets the four-electron transfer reaction of iodine ions, realizes efficient transfer of multiple electrons, improves the capacity of electrode materials, and increases the energy density of batteries. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 : Schematic diagram of the mechanism of coordinated catalysis of molybdenum-boron soft and hard Lewis acids in the embodiment;
[0025] Figure 2 : Battery performance diagram of different current densities under molybdenum-boron synergistic catalysis in the embodiment;
[0026] Figure 3 In the embodiment, the current density under the coordinated catalysis of molybdenum and boron is 2 A g -1 The charge and discharge curves at the 13th and 23rd cycles of the lower cycle;
[0027] Figure 4 : Battery cycle performance diagram under boron-molybdenum synergistic catalysis in the embodiment;
[0028] Figure 5 : Battery performance diagram at different current densities when only boron is used as catalyst in Comparative Example 1;
[0029] Figure 6 In comparative example 1, only boron was used as catalyst and the current density was 2A g -1 The charge and discharge curves at the 13th and 23rd cycles;
[0030] Figure 7 : Battery cycle performance diagram under boron catalysis only in Comparative Example 1;
[0031] Figure 8 : Battery performance diagram at different current densities when only molybdenum is used as catalyst in Comparative Example 2;
[0032] Fig. 9 :In Comparative Example 2, the current density under only molybdenum catalysis is 2A g -1 The charge and discharge curves at the 13th and 23rd cycles;
[0033] Fig.10 : Battery cycle performance diagram under only molybdenum catalysis in Comparative Example 2;
[0034] Fig.11 : Mapping diagram of molybdenum-boron soft and hard Lewis acid synergistic catalysts in the examples. DETAILED DESCRIPTION
[0035] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.
[0036] As described in the background technology section, I formed during the electrooxidation of iodine + The nucleophilic attack of the OH part of water leads to hydrolysis, which makes the reversibility of the four-electron transfer worse. At the same time, the stable cycle of the zinc anode in aqueous electrolyte faces the challenges of hydrogen evolution, surface corrosion and dendrite formation, which will exhaust the electrolysis during long-term cycling. These together lead to the low coulombic efficiency, poor electrochemical stability and low battery capacity of the iodine-based four-electron transfer battery.
[0037] Based on this, the purpose of the present invention is to provide a battery in which molybdenum-boron soft and hard Lewis acids synergistically catalyze iodine-based four-electron transfer. The present invention mixes a boron source and a molybdenum source with activated carbon, and calcines them to obtain a molybdenum-boron soft and hard Lewis acid synergistic catalyst. Then, it is mixed with iodine, ground, heated and filled with iodine, so that the iodine element fully enters the pores of the activated carbon, and a positive electrode material synergistically catalyzed by molybdenum-boron soft and hard Lewis acids is obtained. With this material as the positive electrode material, the negative electrode is metal zinc foil, and the electrolyte is zinc chloride solution, an aqueous battery is assembled to achieve four-electron transfer of the iodine electrode (2I − - 2e − ↔ I2; I2- 2e − + 2Cl − ↔ 2 ICl ). The reaction kinetics of the four-electron transfer process of iodine is slow, and a catalyst is needed to accelerate the reaction. According to the Lewis acid-base theory "soft base-soft acid, hard base-hard acid" principle, the present invention introduces boron (hard Lewis acid) and molybdenum (soft Lewis acid) to synergistically catalyze Cl - (Hard Lewis base) with I -(soft Lewis base), forming a coordinated transition state, reducing the reaction activation energy, improving the reaction kinetics, and achieving complete four-electron transfer. The use of Lewis acid-base theory for collaborative catalysis means that according to the "hard acid-hard base" and "soft acid-soft base" coordination transition state formation principles, boron (hard Lewis acid) and chloride ions (hard Lewis base), molybdenum (soft Lewis acid) and iodide ions (soft Lewis base) are more likely to form transition states, achieving molybdenum-boron collaborative catalysis and reducing the electrochemical barrier of iodine-based four-electron transfer reactions.
[0038] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.
[0039] Note: The conductive carbon used in the present invention is IMICAL SUPER C45 carbon black conductive agent, purchased from Hefei Kejing Material Technology Co., Ltd.;
[0040] The activated carbon was high surface area activated carbon, model AB-520, purchased from Hefei Kejing Material Technology Co., Ltd.
[0041] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.
[0042] Example: Preparation of a battery with iodine-based four-electron transfer catalyzed by molybdenum-boron soft and hard Lewis acids
[0043] (1) Introducing boron source and molybdenum source: Add 70 mg of borax and 100 mg of molybdenum nitrate to 50 mL of ultrapure water, stir, then add 200 mg of activated carbon and stir overnight. Collect the precipitate and wash it twice with ultrapure water, and place it in a vacuum drying oven at 80°C for vacuum drying.
[0044] (2) The powder obtained after drying was placed in a porcelain boat and calcined in a N2 atmosphere at a heating rate of 5°C / min. The temperature was raised to 1000°C and maintained for 2 hours to obtain a molybdenum-boron soft and hard Lewis acid synergistic catalyst. The mapping diagram is shown in Fig.11 , it can be seen that boron and molybdenum are evenly distributed on the activated carbon.
[0045] (3) Weigh the calcined molybdenum-boron soft and hard Lewis acid synergistic catalyst, mix it with iodine element in a mass ratio of 1:2, grind it with an agate mortar for 30 minutes, and after grinding evenly, place it in a reactor at 100°C for 6 hours to obtain a positive electrode material synergistically catalyzed by molybdenum-boron soft and hard Lewis acid.
[0046] (4) Sodium carboxymethyl cellulose was used as the positive electrode material binder, conductive carbon was used as the conductive agent, and the positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids: conductive agent: positive electrode material binder were mixed in a mass ratio of 8:1:1 and coated on a titanium foil current collector. The loading amount of the positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids was 1.5 mg cm -2 Using metal zinc foil as the negative electrode, glass fiber as the separator, and 3M zinc chloride as the electrolyte, a button cell was assembled to obtain a cell in which molybdenum-boron soft and hard Lewis acids synergistically catalyzed iodine-based four-electron transfer.
[0047] The electrochemical performance of the battery prepared in the example for the coordinated catalysis of iodine-based four-electron transfer by molybdenum-boron soft and hard Lewis acids was tested using Chenhua CHI660E and Blue Power CT2001A electrochemical workstations.
[0048] Figure 1 The mechanism of the synergistic catalysis of molybdenum-boron soft and hard Lewis acids is shown in 2I − - 2e − ↔ I2, due to I − It is a soft Lewis base and needs a soft Lewis acid molybdenum to form a transition state, reduce the activation energy, and accelerate the reaction kinetics. − + 2Cl − ↔ 2 During the ICl process, Cl − It is a hard Lewis base, which requires a hard Lewis acid boron to combine with it to form a transition state and catalyze the reaction. In summary, the synergistic catalysis of molybdenum boron soft and hard Lewis acids helps to achieve efficient iodine-based four-electron transfer reactions. Figure 2 The battery performance diagram of the battery prepared in the example of molybdenum-boron soft and hard Lewis acid synergistically catalyzing iodine-based four-electron transfer at different current densities, selecting 0.5, 1, 2, 5, 2, 1, 0.5 A g -1 The current density was tested. When the current density was 0.5, 1, 2, and 5 A g -1 The discharge specific capacities are 180, 160, 143, and 119 mAh g -1 After 20 cycles, the current density was set to 2, 1, and 0.5 A g -1 , and their discharge specific capacities are 140, 156, and 162 mAh g -1 , indicating that four-electron transfer has higher specific capacity and battery performance. Figure 3 The current density is 2A g -1 In the charge-discharge curves at the 13th and 23rd cycles of the next cycle, two sets of obvious voltage platforms can be seen, corresponding to the iodine four-electron transfer (2I − - 2e − ↔ I2; I2- 2e −+ 2Cl − ↔ 2 ICl ), with a specific capacity of 140 mAh g -1 , 138 mAh g -1 Under the synergistic catalysis of molybdenum and boron, the battery has a higher capacity, improved electron transfer efficiency, and more complete transfer of four electrons of iodine ions. Figure 4 The cell under the coordinated catalysis of molybdenum and boron is 1A g -1 Long cycle performance at low current density: when the battery is cycled to 200 cycles, its specific capacity remains at 120 mAh g in the presence of the synergistic catalyst. -1 , with a higher specific capacity, indicating that the synergistic catalysis of soft and hard Lewis acids can reduce the electrochemical barriers of the four-electron transfer reaction of iodide ions to a certain extent and improve the performance of the battery.
[0049] Comparative Example 1
[0050] (1) Introducing only the boron source: Add 70 mg of borax to 50 mL of ultrapure water, stir, then add 200 mg of activated carbon and stir overnight. Collect the precipitate and wash it twice with ultrapure water, and place it in a vacuum drying oven at 80°C to dry it under vacuum.
[0051] (2) The powder obtained after drying was placed in a porcelain boat and calcined in a N2 atmosphere at a heating rate of 5°C / min to 1000°C and maintained for 2 h to obtain a boron catalyst.
[0052] (3) Weigh the calcined boron catalyst, mix and grind it with iodine in a mass ratio of 1:2, and after grinding evenly, place it in a reactor at 100° C. to react for 6 hours to obtain a boron hard Lewis acid-catalyzed positive electrode material.
[0053] (4) Sodium carboxymethyl cellulose was used as the positive electrode material binder, conductive carbon was used as the conductive agent, and the boron hard Lewis acid catalyzed positive electrode material: conductive agent: positive electrode material binder were mixed in a mass ratio of 8:1:1 and coated on a titanium foil current collector. The loading amount of the boron hard Lewis acid catalyzed positive electrode material was 1.5 mg cm -2 Using metal zinc foil as the negative electrode, glass fiber as the separator, and 3M zinc chloride as the electrolyte, a button cell was assembled to obtain a battery in which boron hard Lewis acid synergistically catalyzed iodine-based four-electron transfer.
[0054] The electrochemical performance of the battery prepared in Example 1 was tested using Chenhua CHI660E and Blue Power CT2001A electrochemical workstations.
[0055] Figure 5 The battery performance diagram of the battery prepared in Comparative Example 1 at different current densities is shown in Figure 1. 0.5, 1, 2, 5, 2, 1, and 0.5 A g -1 The current density was tested. When the current density was 0.5, 1, 2, and 5 A g-1 The discharge specific capacities are 83, 72, 68, and 62 mAh g -1 After 20 cycles, the current density was set to 2, 1, and 0.5 A g -1 , and their discharge specific capacities are 67, 70, and 74 mAh g -1 Compared with the embodiment, the specific capacity of the reaction cell in which only boron source hard Lewis acid is used to catalyze chloride ion transfer to produce iodine chloride is lower. Figure 6 The current density is 2A g -1 The charge and discharge curves at the 13th and 23rd cycles of the next cycle have a specific capacity of 66 mAh g -1 , 64mAh g -1 . Figure 7 The battery is at 1A g -1 Long cycle performance under current density: when the battery is cycled to 200 times, the battery specific capacity is maintained at about 78 mAh g -1 . This indicates that the presence of only boron hard Lewis acid cannot achieve the synergistic catalytic effect, resulting in a lower iodine capacity, which fully demonstrates the advantage of molybdenum-boron synergistic catalysis.
[0056] Comparative Example 2
[0057] S1: Introduce only the molybdenum source: add 100 mg of molybdenum nitrate to 50 mL of ultrapure water, stir, then add 200 mg of activated carbon and stir overnight, collect the precipitate and wash it twice with ultrapure water, and place it in a vacuum drying oven at 80°C for vacuum drying.
[0058] (2) The powder obtained after drying was placed in a porcelain boat and calcined in a N2 atmosphere at a heating rate of 5°C / min to 1000°C and maintained for 2 h to obtain a molybdenum catalyst.
[0059] (3) Weigh the calcined carbon powder, mix and grind it with elemental iodine in a mass ratio of 1:2, and after grinding evenly, place it in a reactor at 100° C. to react for 6 hours to obtain a positive electrode material catalyzed by molybdenum soft Lewis acid.
[0060] (4) Sodium carboxymethyl cellulose was used as the positive electrode material binder, conductive carbon was used as the conductive agent, and the molybdenum soft Lewis acid catalyzed positive electrode material: conductive agent: positive electrode material binder were mixed in a mass ratio of 8:1:1 and coated on a titanium foil current collector. The loading amount of the molybdenum soft Lewis acid catalyzed positive electrode material was 1.5 mg cm -2 Using metal zinc foil as the negative electrode, glass fiber as the separator, and 3M zinc chloride as the electrolyte, a button cell was assembled to obtain a cell in which molybdenum soft Lewis acid synergistically catalyzed iodine-based four-electron transfer.
[0061] The electrochemical performance of the battery prepared in Comparative Example 2 was tested using Chenhua CHI660E and Blue Power CT2001A electrochemical workstations.
[0062] Figure 8 The battery performance diagram of the battery prepared in Comparative Example 2 at different current densities is shown in Figure 2. 0.5, 1, 2, 5, 2, 1, and 0.5 A g -1 The current density was tested. When the current density was 0.5, 1, 2, and 5 A g -1 The discharge specific capacities are 67, 53, 47, and 42 mAh g -1 After 20 cycles, the current density was set to 2, 1, and 0.5 A g -1 , and their discharge specific capacities are 46, 50, and 55 mAh g -1 Compared with Example 1, the battery capacity is lower when only molybdenum soft Lewis acid catalyzes the transfer reaction of iodine ions to elemental iodine. Fig. 9 The current density is 2A g -1 The charge and discharge curves at the 13th and 23rd cycles of the next cycle have a specific capacity of 47 mAh g -1 , 46mAh g -1 . Fig.10 The cell is at 1A g in the presence of only molybdenum source. -1 Long cycle performance under current density: when the battery is cycled to 200 times, the battery specific capacity is maintained at about 65 mAh g -1 . This indicates that the presence of molybdenum soft Lewis acid alone cannot achieve the synergistic catalytic effect, resulting in a lower iodine capacity, which fully demonstrates the advantage of molybdenum-boron synergistic catalysis.
[0063] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A battery in which molybdenum-boron soft and hard Lewis acids synergistically catalyze iodine-based four-electron transfer, characterized in that: The battery comprises a positive electrode, a negative electrode and an electrolyte; the positive electrode contains a positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids; the negative electrode is a metal zinc foil; and the electrolyte is a solution containing zinc ions; The positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids is prepared by the following method: (1) mixing a boron source, a molybdenum source and activated carbon, and calcining them under an inert atmosphere to obtain a molybdenum-boron soft and hard Lewis acid synergistic catalyst; (2) The molybdenum-boron soft and hard Lewis acid synergistic catalyst is mixed with iodine and ground, and then subjected to heat treatment to obtain a positive electrode material synergistically catalyzed by molybdenum-boron soft and hard Lewis acid.
2. The battery according to claim 1, characterized in that In step (1), the boron source is borax; and the molybdenum source is molybdenum nitrate.
3. The battery according to claim 1, characterized in that In step (1), the mass ratio of the boron source, the molybdenum source and the activated carbon is 7:10:20; the mixing method includes adsorption method, co-precipitation method, hydrolysis method, hydrothermal method or grinding mixing method.
4. The battery according to claim 1, characterized in that In step (1), the calcination temperature is 800-1200°C, the calcination time is 2-8 hours, and the calcination heating rate is 5°C / min.
5. The battery according to claim 1, characterized in that In step (2), the mass ratio of the molybdenum-boron soft and hard Lewis acid synergistic catalyst to iodine is 1:1-4.
6. The battery according to claim 1, characterized in that In step (2), the heating treatment temperature is 90-120° C., and the heating treatment time is 6-10 h.
7. The battery according to claim 1, characterized in that The positive electrode is obtained by mixing and coating a positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids, a conductive agent and a positive electrode material binder.
8. The battery according to claim 7, characterized in that The positive electrode material binder is sodium carboxymethyl cellulose; the conductive agent is conductive carbon; the mass ratio of the positive electrode material catalyzed by molybdenum-boron soft and hard Lewis acids, the conductive agent and the positive electrode material binder is 8:1:
1.
9. The battery according to claim 1, characterized in that The loading amount of the positive electrode material catalyzed by the molybdenum-boron soft and hard Lewis acid in the positive electrode is 1-2 mg cm -2 .
10. Use of the battery according to any one of claims 1 to 9 in improving the coulombic efficiency, electrochemical stability and capacity of aqueous batteries.