A method for preparing a Ca-I2 dual-ion battery
By introducing I2 as the positive electrode material and C24H10N2O4 as the negative electrode material into the calcium-ion battery, and combining the insertion and extraction reactions of Ca ions and the redox reactions of I ions, the problems of slow transport kinetics and electrostatic interaction in calcium-ion batteries are solved, achieving high energy density and good rate performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2023-09-01
- Publication Date
- 2026-05-12
AI Technical Summary
The slow transport kinetics between the positive and negative electrode materials in calcium-ion batteries result in lower rate and power performance. Furthermore, the electrostatic interaction between calcium ions and electrode materials inhibits the intercalation reaction, affecting energy density.
A Ca-I2 dual-ion battery structure is adopted, in which the positive electrode material is I2 and the negative electrode material is activated C24H10N2O4. 5M CaCl2 is used as the electrolyte. By combining the insertion and extraction reaction of Ca ions and the redox reaction of I ions, the diffusion path of calcium ions is shortened and the reaction rate of the positive electrode is improved.
It improves the rate performance and power density of the battery, achieving an energy density of up to 109 Wh kg-1 and a discharge specific capacitance retention rate of 98.2%, with a capacity retention rate of 90.3% after 5000 cycles.
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Figure CN117080583B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of calcium-ion battery technology, specifically a method for preparing a Ca-I2 dual-ion battery. Background Technology
[0002] Calcium-ion batteries, as multivalent metal-ion batteries, have a higher charge transfer number and a theoretically higher specific capacity (1337 mAh g⁻¹) due to the absence of dendrites. -1 The advantages of calcium-ion batteries, such as their ability to form a passivation layer, have been widely studied. The working principle of calcium-ion batteries is similar to that of lithium-ion batteries. During charging, calcium ions migrate from the positive electrode to the negative electrode through the electrolyte and react with it. During discharging, calcium ions migrate from the negative electrode to the positive electrode and react with it. The choice of positive and negative electrode materials and electrolyte directly affects the overall performance of the calcium-ion battery. For negative electrode materials, based on different energy storage mechanisms, they are mainly divided into three categories: Ca metal anodes, alloy compound anodes, and intercalated anode materials. Ca metal, when used directly as the anode, undergoes a deposition / stripping reaction during charging and discharging. Ca is abundant and can be used directly as the anode. However, many studies have found that an irreversible passivation layer forms on the surface of the Ca anode during the reaction, blocking the diffusion channels of Ca ions and thus inhibiting the reversible deposition / stripping reaction of calcium ions, resulting in a low coulombic efficiency. Currently, only a few ether-based organic electrolytes can inhibit the formation of the passivation film, thereby supporting the reversible deposition / stripping reaction of metallic Ca. Alloy compound anodes typically have a high discharge specific capacity. Taking silicon-based anodes as an example, at a voltage of around 0.37V, calcium and silicon form an intermetallic compound Ca. x Si phase; however, for intercalated anode materials, insertion-extraction reactions often occur, with calcium ions inserting into the interlayer to form interlayer intercalation compounds during discharge. For calcium-ion battery cathode materials, insertion-extraction reactions often occur, including layered oxides (such as Ca). 0.28 During the charging process, V₂O₅⋅H₂O causes calcium ions to move from Ca²⁺ to H₂O. 0.28 Extracted from V2O5⋅H2O and migrated to the negative electrode through the electrolyte), Prussian blue analogues (such as K2BaFe(CN)6), polyanionic compounds (such as layered Na2FePO4F), transition metal oxides (such as CaMn2O4), and organic electrode materials (such as C 24 H8O6). The matching of positive and negative electrode materials directly determines the performance of calcium-ion batteries. For example, using mesophase carbon microspheres with intercalation-deintercalation reaction mechanisms as the negative electrode material, Ca... 0.28 V₂O₅⋅H₂O is used as the positive electrode material. During the charging process of the entire battery, calcium ions move from Ca²⁺ to Ca²⁺. 0.28 Calcium ions are released from V₂O⋅H₂O and intercalated into the mesophase carbon microspheres via the electrolyte. During discharge, calcium ions are released from the mesophase carbon microspheres and intercalated into the CaO microspheres via the electrolyte.0.28 V2O5⋅H2O.
[0003] Currently, the configuration of calcium-ion batteries mainly involves calcium ions shuttling back and forth between the positive and negative electrode materials to convert chemical energy into electrical energy. However, due to the large radius of calcium ions, the kinetic process during the entire transport is slow, which affects the rate performance and power performance of the battery. In addition, because calcium ions have a large charge, they are extremely prone to electrostatic interactions with the electrode materials, inhibiting the intercalation reaction. Therefore, the energy density is not high. In view of the above situation, there is an urgent need to develop a method for preparing Ca-I2 dual-ion batteries to overcome the shortcomings in current practical applications. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing a Ca-I2 dual-ion battery to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A method for preparing a Ca-I2 dual-ion battery specifically includes the following steps:
[0007] (1) Place a 5M CaCl2 aqueous solution as the electrolyte in the electrolytic cell for the Ca-I2 dual-ion battery;
[0008] (2) Elemental iodine and activated carbon fiber cloth are placed together in a sealed glass container to solidify iodine, and the solidified carbon fiber cloth is used as the positive electrode material.
[0009] (3) The electrode sheet is obtained by drying the carbon fiber paper coated with slurry. The fully dried electrode sheet is activated by electrochemical cyclic voltammetry and the activated electrode sheet is used as the negative electrode material.
[0010] (4) The positive electrode material obtained in step (2) and the negative electrode material obtained in step (3) are placed together in the electrolyte in step (1) and a Ca-I2 dual-ion battery is obtained by matching.
[0011] As a further aspect of the present invention: in step (2), before solidification with iodine, the carbon fiber cloth is first air-annealed in a muffle furnace to construct a multi-level porous structure on the surface, wherein the temperature in the muffle furnace is 450°C and the annealing time is 2 hours.
[0012] As a further aspect of the present invention: in step (2), before solidifying iodine, the elemental iodine is first thoroughly ground into powder.
[0013] As a further aspect of the present invention: In step (2), after the elemental iodine and the activated carbon fiber cloth are placed together in a sealed glass container, the sealed glass container is placed in a forced-air drying oven and reacted at 120°C for 3 hours. Then, the oven is cooled to 80°C and kept warm for another hour. After that, it is cooled to room temperature so that the elemental iodine is completely volatilized and fixed on the surface of the carbon fiber.
[0014] As a further aspect of the present invention: in step (3), the slurry is C 24 H 10 The N2O4, super P and Nafion membrane solution were prepared in a mass ratio of 7:1.5:1.5, with ethanol as the solvent.
[0015] As a further aspect of the present invention: in step (3), the carbon fiber paper is cut into 1×1.5 cm pieces. 2 The rectangular carbon fiber paper was ultrasonically cleaned for 20 minutes each with acetone, ethanol and deionized water, and then placed in a 60°C oven to dry thoroughly.
[0016] As a further aspect of the present invention: in step (3), the activation method of the electrochemical cyclic voltammetry is specifically as follows:
[0017] A platinum sheet and a saturated calomel electrode were used as the counter and reference electrodes, respectively. An electrode sheet was used as the working electrode. 0.5 M CaCl2 was used as the electrolyte. The scan rate was 3 mV / s. -1 The scanning potential range is -1 to 0 V.
[0018] As a further aspect of the present invention: in step (3), the electrode sheet is dried at a temperature of 60°C.
[0019] Compared with the prior art, the beneficial effects of the present invention are:
[0020] (1) The novel Ca-I2 dual-ion battery prepared in this invention combines the insertion / extraction reaction of Ca ions with the redox reaction of I ions for the first time. Using 5M CaCl2 as the electrolyte, the redox reaction of iodine occurs at the positive electrode, while Ca ions at the negative electrode undergo a redox reaction at C... 24 H 10 Intercalation and deintercalation reactions occur within N₂O₄, forming a dual-ion battery. Overall, this novel Ca-I₂ battery exhibits a significant rate advantage at 1000 mA g⁻¹. -1 It can reach a current density of up to 57 mAh g -1 The discharge specific capacitance, while when the current density increases to 3000 mA g -1 The discharge specific capacitance retention rate is as high as 98.2%, and it reaches 1900 W kg. -1 It has a power density of 109 Wh kg-1 The energy density is 90.3% after 5000 charge-discharge cycles;
[0021] (2) In this dual-ion battery, Ca ions do not need to be extracted from the positive electrode material and diffuse to the negative electrode for intercalation during charging. Ca ions can directly diffuse from the electrolyte to the negative electrode to react, greatly reducing the ion diffusion path. Therefore, the entire battery has a higher power density under the same conditions. In addition, the positive electrode material we designed is I2, which undergoes a redox reaction at the positive electrode. This reaction is faster than the intercalation and extraction reaction, thus further improving the power density of the battery. At the same time, avoiding the electrostatic interaction between Ca ions and the negative electrode material at the positive electrode results in a considerable energy density for the entire battery.
[0022] In summary, the Ca-I2 dual-ion battery of this invention utilizes activated C 24 H 10 Using N2O4 as the negative electrode active material, I2 as the positive electrode active material, and 5M CaCl2 as the electrolyte, a dual-ion battery with a potential of 1.9V is achieved. Due to the calcium ion diffusion distance being shortened by half and the rapid redox reaction occurring at the positive electrode, the entire battery exhibits good rate performance and high power density and energy density. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the Ca-I2 dual-ion battery structure in an embodiment of the present invention.
[0024] Figure 2 This is a schematic diagram of the constant current charge-discharge test results of the Ca-I2 dual-ion battery in an embodiment of the present invention.
[0025] Figure 3 This is a graph showing the energy density and power density of the full battery in an embodiment of the present invention.
[0026] Figure 4 This is a schematic diagram comparing the stability of the full battery in an embodiment of the present invention. Detailed Implementation
[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.
[0029] Please see Figures 1-4 The present invention provides a method for preparing a Ca-I2 dual-ion battery, which specifically includes the following steps:
[0030] (1) Place a 5M CaCl2 aqueous solution as the electrolyte in the electrolytic cell for the Ca-I2 dual-ion battery;
[0031] (2) Elemental iodine and activated carbon fiber cloth are placed together in a sealed glass container to solidify iodine, and the solidified carbon fiber cloth is used as the positive electrode material.
[0032] (3) The electrode sheet is obtained by drying the carbon fiber paper coated with slurry. The fully dried electrode sheet is activated by electrochemical cyclic voltammetry and the activated electrode sheet is used as the negative electrode material.
[0033] (4) The positive electrode material obtained in step (2) and the negative electrode material obtained in step (3) are placed together in the electrolyte in step (1) to obtain a Ca-I2 dual-ion battery by matching.
[0034] In step (2), before iodine fixation, the carbon fiber cloth is first air annealed in a muffle furnace to build a multi-level porous structure on the surface, wherein the temperature in the muffle furnace is 450°C and the annealing time is 2 hours.
[0035] In step (2), before solidification, the elemental iodine is first thoroughly ground into powder.
[0036] In step (2), after the elemental iodine and the activated carbon fiber cloth are placed together in a sealed glass container, the sealed glass container is placed in a forced-air drying oven and reacted at 120°C for 3 hours. Then, the oven is cooled to 80°C and kept at that temperature for another hour. After that, it is cooled to room temperature so that the elemental iodine is completely volatilized and fixed on the surface of the carbon fiber.
[0037] In step (3), the slurry is C 24 H 10 The N2O4, super P and Nafion membrane solution were prepared in a mass ratio of 7:1.5:1.5, with ethanol as the solvent.
[0038] In step (3), the carbon fiber paper is cut into 1×1.5 cm pieces. 2 The rectangular carbon fiber paper was ultrasonically cleaned for 20 minutes each with acetone, ethanol and deionized water, and then placed in a 60°C oven to dry thoroughly.
[0039] In step (3), the activation method of the electrochemical cyclic voltammetry is as follows:
[0040] A platinum sheet and a saturated calomel electrode were used as the counter and reference electrodes, respectively. An electrode sheet was used as the working electrode. 0.5 M CaCl2 was used as the electrolyte. The scan rate was 3 mV / s. -1 The scanning potential range is -1 to 0 V.
[0041] In step (3), the electrode sheet is dried at a temperature of 60°C.
[0042] The novel Ca-I₂ dual-ion battery prepared in this invention combines the intercalation / deintercalation reaction of Ca ions with the redox reaction of I ions for the first time. Using 5M CaCl₂ as the electrolyte, the redox reaction of iodine occurs at the positive electrode, while Ca ions at the negative electrode undergo a redox reaction at C₂. 24 H 10 Intercalation and deintercalation reactions occur within N₂O₄, forming a dual-ion battery. Overall, this novel Ca-I₂ battery exhibits a significant rate advantage at 1000 mA g⁻¹. -1 It can achieve up to 57 mAh g at current densities. -1 The discharge specific capacitance, while when the current density increases to 3000 mA g -1 The discharge specific capacitance retention rate is as high as 98.2%, and it reaches 1900 W kg. -1 It has a power density of 109 Wh kg -1 The energy density is 90.3% after 5000 charge-discharge cycles;
[0043] In this dual-ion battery, Ca ions do not need to be extracted from the positive electrode material and diffuse to the negative electrode for intercalation during charging. Ca ions can directly diffuse from the electrolyte to the negative electrode to react, greatly reducing the ion diffusion path. Therefore, the entire battery has a higher power density under the same conditions. In addition, the positive electrode material we designed is I2, which undergoes a redox reaction at the positive electrode. This reaction is faster than the intercalation and extraction reaction, thus further improving the power density of the battery. At the same time, avoiding electrostatic interaction between Ca ions and the negative electrode material at the positive electrode results in a considerable energy density for the entire battery.
[0044] In summary, the Ca-I2 dual-ion battery of this invention utilizes activated C 24 H 10 Using N2O4 as the negative electrode active material, I2 as the positive electrode active material, and 5M CaCl2 as the electrolyte, a dual-ion battery with a potential of 1.9V is achieved. Due to the calcium ion diffusion distance being shortened by half and the rapid redox reaction occurring at the positive electrode, the entire battery exhibits good rate performance and high power density and energy density.
[0045] In one embodiment of the present invention, such as Figure 2As shown, for the entire battery system, commercial C 24 H 10 N2O4 was mixed with a conductive agent (super P) and a binder (Nafion film solution) in a mass ratio of 7:1.5:1.5 to prepare an electrode slurry. Ethanol was used as a solvent to coat the slurry onto a carbon fiber paper substrate. The dried electrode was then used directly as the negative electrode material for a Ca-I2 dual-ion battery, where Ca ion insertion and extraction reactions occurred.
[0046] Commercially available elemental I2 was thoroughly ground into a uniform powder and placed together with activated carbon fiber cloth that had been air-annealed at 450°C for 2 hours in a sealed glass bottle. The mixture was reacted at 120°C for 3 hours, then cooled to 80°C in the furnace and held at that temperature for another hour. Afterward, it was cooled to room temperature, allowing the elemental I2 to be fully immobilized within the hierarchical porous structure of the carbon fiber cloth. The resulting iodine-fixed carbon fiber cloth was then used directly as the cathode material. Utilizing activated carbon fiber cloth as a carrier for elemental I2, the hierarchical porous structure of the annealed and activated carbon fiber cloth effectively immobilizes iodine, resulting in excellent cycle stability for the entire battery.
[0047] The above-mentioned positive electrode generates I2 elemental to I - The redox reaction was matched for the first time to create a Ca-I2 dual-ion battery, the structure of which is as follows: Figure 1 As shown, the potential window can reach 1.9V, thanks to the redox effect of I2 and the halving of the Ca ion diffusion distance, as well as C 24 H 10 The presence of numerous benzene rings within N2O4 facilitates the formation of channels and voids, providing pathways for the rapid transport of Ca ions.
[0048] To address the drawbacks of calcium ions, such as their large radius, slow migration between the positive and negative electrodes and the electrolyte, their sluggish kinetics, their high charge density leading to strong electrostatic interactions with electrode materials, resulting in low overall energy density and poor stability, a novel Ca-I2 dual-ion battery has been developed, based on calcium ion configuration. This battery utilizes the redox reaction of I2 to replace the traditional Ca ion insertion / extraction reaction at the positive electrode, avoiding electrostatic interactions between calcium ions and the positive electrode. Furthermore, the faster kinetics of the I2 redox reaction improve the overall rate performance of the battery. More importantly, unlike traditional calcium ion batteries that require Ca ions to shuttle back and forth between the positive and negative electrodes and the electrolyte, the Ca-I2 dual-ion battery allows calcium ions to migrate directly from the electrolyte to the C2 electrode during charging and discharging. 24 H 10The N₂O₄ anode undergoes an insertion (extraction) reaction, while the I₂ cathode undergoes a reduction (oxidation) reaction. This directly halves the calcium ion migration path, effectively improving the power density and rate performance of the entire cell. Therefore, the entire Ca-I₂ battery exhibits excellent performance at 1000 mA g⁻¹. -1 It has a current density of up to 57 mAh g -1 The discharge specific capacitance, while when the current density increases to 3000 mA g -1 The discharge specific capacitance retention rate is as high as 98.2%, and it reaches 1900 W kg. -1 It has a power density of 109Wh kg -1 The energy density is 90.3% after 5000 charge-discharge cycles.
[0049] In one embodiment of the present invention, such as Figure 3 As shown, the matched Ca-I2 dual-ion battery has significant advantages over the traditional calcium-ion battery. The energy density and power density curves show that this Ca-I2 dual-ion battery has significantly better rate performance and power density. This is due to the rapid reaction kinetics of I2 redox and its relatively good stability, as well as the fact that the calcium ion migration path is directly shortened by half, which accelerates the entire battery kinetic process.
[0050] In one embodiment of the present invention, such as Figure 4 As shown, the matched Ca-I2 dual-ion battery also has an advantage in stability compared with the traditional calcium-ion battery. The stability comparison curve shows that the Ca-I2 battery still has a high discharge specific capacity after 5000 cycles. This is due to the fact that the redox reaction of I2 replaces the original Ca ion insertion and extraction reaction at the positive electrode, avoiding the electrostatic interaction between calcium ions and the positive electrode, thus enhancing the stability of the positive electrode and improving the overall stability.
[0051] It should be noted that, in this invention, although the specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A method for preparing a Ca-I2 dual-ion battery, characterized in that, Specifically, the following steps are included: (1) Place a 5M CaCl2 aqueous solution as the electrolyte in the electrolytic cell for the Ca-I2 dual-ion battery; (2) Elemental iodine and activated carbon fiber cloth are placed together in a sealed glass container to solidify iodine, and the solidified carbon fiber cloth is used as the positive electrode material. (3) The electrode sheet is obtained by drying the carbon fiber paper coated with slurry. The fully dried electrode sheet is activated by electrochemical cyclic voltammetry and the activated electrode sheet is used as the negative electrode material. (4) The positive electrode material obtained in step (2) and the negative electrode material obtained in step (3) are placed together in the electrolyte in step (1) and a Ca-I2 dual-ion battery is obtained by matching. In step (3), the slurry is C 24 H 10 The N2O4, super P and Nafion membrane solution were prepared in a mass ratio of 7:1.5:1.5, with ethanol as the solvent; In step (3), the activation method of the electrochemical cyclic voltammetry is as follows: A platinum sheet and a saturated calomel electrode were used as the counter and reference electrodes, respectively. An electrode sheet was used as the working electrode. 0.5 M CaCl2 was used as the electrolyte. The scan rate was 3 mV / s. -1 The scanning potential range is -1 to 0 V.
2. The method for preparing the Ca-I2 dual-ion battery according to claim 1, characterized in that, In step (2), before iodine fixation, the carbon fiber cloth is first air annealed in a muffle furnace to build a multi-level porous structure on the surface, wherein the temperature in the muffle furnace is 450°C and the annealing time is 2 hours.
3. The method for preparing the Ca-I2 dual-ion battery according to claim 2, characterized in that, In step (2), before solidification, the elemental iodine is first thoroughly ground into powder.
4. The method for preparing a Ca-I2 dual-ion battery according to any one of claims 1-3, characterized in that, In step (2), after the elemental iodine and the activated carbon fiber cloth are placed together in a sealed glass container, the sealed glass container is placed in a forced-air drying oven and reacted at 120°C for 3 hours. Then, the oven is cooled to 80°C and kept at that temperature for another hour. After that, it is cooled to room temperature so that the elemental iodine is completely volatilized and fixed on the surface of the carbon fiber.
5. The method for preparing a Ca-I2 dual-ion battery according to claim 1, characterized in that, In step (3), the carbon fiber paper is cut into 1×1.5 cm pieces. 2 The rectangular carbon fiber paper was ultrasonically cleaned for 20 minutes each with acetone, ethanol and deionized water, and then placed in a 60°C oven to dry thoroughly.
6. The method for preparing a Ca-I2 dual-ion battery according to claim 1, characterized in that, In step (3), the electrode sheet is dried at a temperature of 60°C.