Preparation method of phthaloyl gelatin adhesive and application of phthaloyl gelatin adhesive in manganese dioxide positive electrode of zinc ion battery

Abstract

The invention relates to a preparation method and application of a phthaloyl gelatin adhesive. Gelatin and phthalic anhydride are subjected to a reaction, such that phthaloyl gelatin is prepared; preparing the obtained phthaloyl gelatin into an adhesive solution, and mixing the adhesive solution with beta-manganese dioxide and conductive carbon to obtain uniform positive electrode slurry; and coating a current collector with the positive electrode slurry to obtain the manganese dioxide positive electrode bonded by the phthaloyl gelatin. According to the invention, the phthaloyl gelatin is used as a positive electrode adhesive; a high-toughness adhesive network of the phthaloyl gelatin can better buffer stress and maintain the structural integrity of the electrode; the free carboxyl group optimizes the electrode-electrolyte wettability, constructs a zinc ion transmission channel, and promotes ion transmission kinetics under high magnification. The bio-based adhesive provides a new strategy for breaking through the stability and rate bottleneck of the zinc ion battery through multi-functional design.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and particularly relates to a method for preparing phthalic acid gelatin adhesive and its application in the manganese dioxide cathode of zinc-ion batteries. Background Technology

[0002] Aqueous zinc-ion batteries have great potential for large-scale energy storage due to their high safety, environmental friendliness, and cost advantages. However, the manganese dioxide cathode exhibits volume changes and sluggish interfacial ion diffusion kinetics during cycling, which severely limits the battery's long-term cycle life and high-rate performance.

[0003] Currently widely used polyvinylidene fluoride (PVDF) adhesives have two bottlenecks: first, their strong hydrophobicity hinders electrolyte wetting and makes it impossible to build efficient ion transport channels; second, their insufficient mechanical rigidity makes it difficult to buffer the stress of repeated deformation of the electrode.

[0004] More seriously, polyvinylidene fluoride (PVDF) requires processing with the toxic solvent N-methylpyrrolidone (NMP), posing risks of environmental pollution and high energy consumption, which contradicts the concept of green battery development. There is an urgent need to develop a novel adhesive system that balances mechanical compatibility, interfacial activity, and environmentally friendly processability. Summary of the Invention

[0005] The technical problem solved by this invention is the technical bottleneck and environmental pollution problem of traditional PVDF adhesives.

[0006] In view of the technical problems existing in the prior art, the present invention designs a method for preparing manganese dioxide positive electrode with phthalic acid gelatin as binder and its application.

[0007] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition definition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," etc., and similar meanings.

[0008] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0009] [The first technical solution]

[0010] A method for preparing a phthalylated gelatin adhesive includes the following steps:

[0011] Step 1: Add gelatin to a solvent to swell and dissolve, obtaining gelatin solution A. Adjust the pH of the system to 9.0 with an alkaline solution.

[0012] Step 2 involves adding phthalic anhydride to the gelatin solution A obtained in Step 1 under water bath heating conditions, stirring magnetically, and continuously adding alkaline solution to maintain the pH of the system at 9.0. After the pH of the system remains unchanged, the reaction continues for 30 minutes to obtain solution B.

[0013] Step 3: Transfer the solution B obtained in Step 2 to a dialysis bag, dialyze with deionized water, and finally freeze-dry the dialyzed product to obtain phthalic acid gelatin adhesive.

[0014] Furthermore, in step 1, the mass fraction of gelatin solution A is 15-20%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-60℃.

[0015] Furthermore, in step 2, the water bath heating temperature is 40-45℃, and the mass ratio of phthalic anhydride to gelatin added is 1:15-1:10; the reaction time is 20-40 minutes.

[0016] The alkaline solution in steps 1 and 2 is a 7M NaOH solution.

[0017] Furthermore, in step 3, the molecular weight cutoff of the dialysis bag is 200-500 Da, and the dialysis time is 48-72 h.

[0018] [Second Technical Solution]

[0019] An application of the above-mentioned manganese dioxide positive electrode with phthalic acid gelatin as a binder in a zinc-manganese battery, wherein a battery is designed and assembled using the above-mentioned manganese dioxide positive electrode with phthalic acid gelatin as a binder and electrochemical tests are performed.

[0020] [The third technical solution]

[0021] The application of the above-mentioned phthalyl gelatin adhesive in the manganese dioxide positive electrode of a zinc-ion battery includes the following steps:

[0022] Step (1) The prepared phthalic acid gelatin adhesive is added to a solvent to swell and then dissolved to obtain phthalic acid gelatin solution C;

[0023] Step (2) Mix β-manganese dioxide, KB carbon, and the phthalic acid gelatin solution C obtained in step (1) and stir magnetically to obtain a uniform positive electrode slurry;

[0024] Step (3) The positive electrode slurry obtained in step (2) is coated onto the current collector and dried in a blower oven to obtain the positive electrode.

[0025] Furthermore, in step (1), the mass fraction of phthalic acid gelatin solution C is 1-2%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-60℃.

[0026] Further, in step (2), after mixing β-manganese dioxide, KB carbon, and phthalic acid gelatin solution C, the mass fraction of β-manganese dioxide is 60-70, the mass fraction of KB carbon is 20-30, the mass fraction of gelatin is 10-15, and the magnetic stirring time is 8-12 hours.

[0027] Furthermore, in step (3), the temperature of the forced-air drying oven is 40-60℃, and the β-manganese dioxide loading on the current collector should be controlled to be 1-2 mg / cm³. -2 .

[0028] In the application of this invention, the specific assembly operation of the zinc-manganese full battery is as follows:

[0029] The process involves placing a manganese dioxide positive electrode inside the positive electrode shell of a button cell, then adding a glass fiber separator and electrolyte (2M ZnSO4, 0.2M MnSO4) to form the positive electrode portion. A foamed nickel and zinc negative electrode is placed inside the negative electrode shell of the button cell to form the negative electrode portion. The negative electrode portion is then gently placed on top of the positive electrode portion, ensuring alignment between the positive and zinc negative electrodes, and finally encapsulated to obtain a zinc-manganese full cell using phthalic acid gelatin as the binder for the manganese dioxide positive electrode.

[0030] [Fourth technical solution]

[0031] A zinc-ion battery manganese dioxide positive electrode is prepared using the above-mentioned phthalic acid gelatin as a binder.

[0032] The manganese dioxide cathode prepared by this invention, using phthalated gelatin as a binder, exhibits superior performance:

[0033] After assembling a zinc-manganese full battery, the manganese dioxide cathode prepared using phthalated gelatin as a binder in the examples exhibits good cycle stability and rate performance. At a 10C charge-discharge rate, its specific capacity remains 288.5 mAh g after 1000 cycles. -1 The capacity retention rate was 89.8%, and the coulombic efficiency was close to 100%. The average specific capacities after 10 cycles at 1C, 2C, 3C, 4C, 5C, and 10C were 373.50, 354.27, 340.77, 327.88, 319.50, and 279.07 mAh g, respectively. -1 .

[0034] These results demonstrate that the prepared manganese dioxide cathode with phthalic acid gelatin as a binder exhibits superior electrochemical performance in the zinc-manganese full battery system.

[0035] During charge-discharge at a 10C rate, the high capacity retention demonstrates the structural stability and resistance to capacity decay. This is attributed to the phthalic acid-modified gelatin's highly resilient adhesive network, which effectively buffers stress and maintains the integrity of the electrode structure.

[0036] The high specific capacity demonstrated by the high rate capability during charge and discharge at different rates is attributed to the introduction of free carboxyl groups, which optimizes electrode-electrolyte wettability, constructs a continuous zinc ion transport channel, and promotes ion transport kinetics at high rates.

[0037] The high coulomb efficiency further confirms that the cathode can achieve highly efficient electrochemical reversibility, and the electrons participating in the reaction can be effectively utilized.

[0038] The manganese dioxide cathode prepared in this invention, using phthalated gelatin as a binder, exhibits excellent cycle performance and rate capability. The mechanism is as follows:

[0039] Phthalate-modified gelatin reshapes the electrode microstructure and optimizes interfacial dynamics through multiple synergistic functions.

[0040] Firstly, the rigid benzene rings in the gelatin molecular chain form a highly resilient three-dimensional network with the flexible gelatin skeleton, which effectively buffers the volume stress during the charging and discharging process of manganese dioxide, inhibits the cracking and peeling of active materials, and ensures the integrity of the electrode structure.

[0041] Secondly, the acylation reaction introduces more free carboxyl groups, constructs continuous ion transport channels, accelerates the diffusion rate of zinc ions inside the cathode, and reduces electrochemical polarization at high rates.

[0042] This invention provides a method for preparing phthalyl gelatin adhesive and its application in the manganese dioxide cathode of zinc-ion batteries, which has the following beneficial effects:

[0043] 1. The manganese dioxide positive electrode prepared by the present invention, which uses phthalic acid gelatin as a binder, enables the zinc-manganese full cell to retain 89.8% of its capacity after 1000 cycles at 10C rate.

[0044] 2. The manganese dioxide cathode prepared by this invention, using phthalated gelatin as a binder, significantly improves the rate performance of zinc-manganese full batteries. The average specific capacities after 10 cycles at 1C, 2C, 3C, 4C, 5C, and 10C rates are 373.50, 354.27, 340.77, 327.88, 319.50, and 279.07 mAh g, respectively. -1

[0045] 3. The manganese dioxide cathode prepared by the present invention, which uses phthaloyl gelatin as a binder, uses water as a solvent in the preparation process, eliminating the use of toxic reagents such as NMP. The bio-based raw material binder has better biocompatibility than synthetic polymers, and the environmental risk after the battery is discarded is significantly reduced.

[0046] 4. The manganese dioxide cathode prepared by this invention utilizes phthaloyl gelatin binder, which provides a highly resilient adhesive network, buffering volume change stress during cycling and thus improving battery cycle performance. The acylation reaction introduces more free carboxyl groups, optimizing electrode-electrolyte wettability and constructing continuous zinc ion transport channels, thereby improving the battery's rate performance. Simultaneously, the good dispersibility, non-toxicity, and environmentally friendly properties of gelatin material make the electrode manufacturing process green. This method can be used to design and prepare highly safe zinc-ion batteries. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the process for preparing the manganese dioxide positive electrode using phthalic acid gelatin as a binder in Example 1 of the present invention. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0049] In embodiments of the present invention, unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art.

[0050] Unless otherwise specified, all reagents and raw materials used in this invention can be purchased from the market.

[0051] In this invention, KB carbon is Ketjen Black, model EC-600JD.

[0052] Preparation of manganese dioxide positive electrode using phthalyl gelatin as binder

[0053] Step 1: Accurately weigh 6.0g of gelatin and 24.0g of deionized water, swell at 38℃ for 5min, then dissolve completely in a 60℃ water bath to obtain gelatin solution A. Adjust the pH of gelatin solution A to 9.0 using 7M NaOH solution.

[0054] Step 2: Under water bath heating at 40℃, add 0.4g of phthalic anhydride to the gelatin solution A obtained in Step 1, stir magnetically, and continuously add 7M NaOH solution to maintain the pH of the system at 9.0. After the pH of the system remains unchanged, continue the reaction for 40 minutes to obtain solution B.

[0055] Step 3: Transfer the solution B obtained in Step 2 to a dialysis bag with a molecular weight cutoff of 500 Da, dialyze with deionized water for 72 h, and finally freeze-dry the dialyzed product to obtain phthalic acid gelatin.

[0056] Step 4: Accurately weigh 0.2g of gelatin and 9.8g of deionized water, swell at 38℃ for 5min, and then dissolve completely in a 60℃ water bath to obtain phthalic acid gelatin solution C.

[0057] Step 5: Mix 0.36g β-manganese dioxide, 0.18g KB carbon, and 3g phthalyl gelatin solution C. To facilitate magnetic stirring, add 2.5ml deionized water and stir magnetically for 12h to obtain a uniform positive electrode slurry.

[0058] Step 6: The positive electrode slurry obtained in Step 5 is coated onto the current collector titanium mesh and dried in a 60℃ forced-air oven to obtain a β-manganese dioxide loading of 1.0 mg / cm³. -2 The manganese dioxide cathode using phthaloyl gelatin as a binder.

[0059] The manganese dioxide positive electrode with phthalic acid gelatin as a binder was assembled with a regular zinc sheet negative electrode to form a battery, and the battery was subjected to cycle performance testing after being left to stand.

[0060] pass Figure 1 The various properties obtained by the present invention are further explained below:

[0061] from Figure 1 As can be seen, the manganese dioxide positive electrode prepared in Example 1 of this invention, which uses phthaloyl gelatin as a binder, has flexible phthaloyl gelatin molecules that can effectively fix manganese dioxide and KB carbon on the current collector and construct a continuous zinc ion transport channel in the zinc-manganese full cell.

[0062] Example 2

[0063] Preparation of manganese dioxide positive electrode using phthalyl gelatin as binder

[0064] Step 1: Accurately weigh 6.0g of gelatin and 34.0g of deionized water, swell at 10℃ for 5min, then dissolve completely in a 50℃ water bath to obtain gelatin solution A. Adjust the pH of gelatin solution A to 9.0 using 7M NaOH solution.

[0065] Step 2: Under water bath heating at 45°C, add 0.5g of phthalic anhydride to the gelatin solution A obtained in Step 1, stir magnetically, and continuously add 7M NaOH solution to maintain the pH of the system at 9.0. After the pH of the system remains unchanged, continue the reaction for 20 minutes to obtain solution B.

[0066] Step 3: Transfer the solution B obtained in Step 2 to a dialysis bag with a molecular weight cutoff of 200 Da, dialyze with deionized water for 48 h, and finally freeze-dry the dialyzed product to obtain phthalic acid gelatin.

[0067] Step 4: Accurately weigh 0.1g of gelatin and 9.9g of deionized water, swell at 10℃ for 5min, and then dissolve completely in a 50℃ water bath to obtain phthaloyl gelatin solution C.

[0068] Step 5: Mix 0.35g of β-manganese dioxide, 0.10g of KB carbon, and 5g of phthalic acid gelatin solution C. To facilitate magnetic stirring, add 2.5ml of deionized water and stir magnetically for 8 hours to obtain a uniform positive electrode slurry.

[0069] Step 6: The positive electrode slurry obtained in Step 5 is coated onto the current collector titanium mesh and dried in a 40℃ forced-air oven to obtain a β-manganese dioxide loading of 2.0 mg / cm³. -2 The manganese dioxide cathode using phthaloyl gelatin as a binder.

[0070] The above-mentioned manganese dioxide positive electrode with phthalic acid gelatin as a binder was assembled with a common zinc sheet negative electrode to form a battery, and the battery was subjected to cycle performance testing after being left to stand.

[0071] The battery assembled in Embodiment 2 of the present invention exhibits superior long-cycle stability after 1000 cycles at a 10C rate. During multiple charge-discharge cycles, it shows a lower capacity decay rate compared to ordinary manganese dioxide cathode batteries using PVDF as a binder.

[0072] Example 3

[0073] Preparation of manganese dioxide positive electrode using phthalyl gelatin as binder

[0074] Step 1: Accurately weigh 6.0g of gelatin and 31.5g of deionized water, swell at 35℃ for 5min, then dissolve completely in a 55℃ water bath to obtain gelatin solution A. Adjust the pH of gelatin solution A to 9.0 using 7M NaOH solution.

[0075] Step 2: Under water bath heating at 43°C, add 0.4g of phthalic anhydride to the gelatin solution A obtained in Step 1, stir magnetically, and continuously add 7M NaOH solution to maintain the pH of the system at 9.0. After the pH of the system remains unchanged, continue the reaction for 30 minutes to obtain solution B.

[0076] Step 3: Transfer the solution B obtained in Step 2 to a dialysis bag with a molecular weight cutoff of 500 Da, dialyze with deionized water for 60 h, and finally freeze-dry the dialyzed product to obtain phthalic acid gelatin.

[0077] Step 4: Accurately weigh 0.15g of gelatin and 9.85g of deionized water, swell at 35℃ for 5min, and then dissolve completely in a 50℃ water bath to obtain phthalic acid gelatin solution C.

[0078] Step 5: Mix 0.325g β-manganese dioxide, 0.125g KB carbon, and 5g phthalic acid gelatin solution C. To facilitate magnetic stirring, add 2.5ml deionized water and stir magnetically for 12h to obtain a uniform positive electrode slurry.

[0079] Step 6: The positive electrode slurry obtained in Step 5 is coated onto the current collector titanium mesh and dried in a 60℃ forced-air oven to obtain a β-manganese dioxide loading of 2.0 mg / cm³. -2 The manganese dioxide cathode using phthaloyl gelatin as a binder.

[0080] The above-mentioned manganese dioxide positive electrode with phthalic acid gelatin as a binder was assembled with a common zinc sheet negative electrode to form a battery, and the battery was subjected to cycle performance testing after being left to stand.

[0081] The battery assembled in Embodiment 3 of the present invention exhibits superior long-cycle stability after 1000 cycles at a 10C rate. During multiple charge-discharge cycles, it shows a lower capacity decay rate compared to ordinary manganese dioxide cathode batteries using PVDF as a binder.

[0082] Comparative Example 1

[0083] Regarding the preparation of manganese dioxide positive electrodes using PVDF binders.

[0084] Step 1: Accurately weigh 0.05g PVDF and 4.95g NMP, mix them, and then magnetically stir at room temperature (20℃) for 8 hours to obtain a homogeneous solution;

[0085] Step 2: Mix 0.35g β-manganese dioxide, 0.1g KB carbon, and 5g PVDF solution, add 2.5ml NMP, and stir magnetically for 12h to obtain a uniform positive electrode slurry;

[0086] Step 3: Coat the positive electrode slurry obtained in Step 2 onto the current collector, and dry it in a 60°C forced-air oven to obtain a manganese dioxide positive electrode with PVDF binder.

[0087] Table 1 shows the rate performance of the zinc-manganese full cell assembled with manganese dioxide cathode using phthalic acid gelatin as a binder prepared in Example 1 of the present invention and the full cell assembled with cathode prepared in Comparative Example 1 at 1C-10C, with each rate being 10 cycles.

[0088] Table 2 shows the performance of the zinc-manganese full cell assembled with manganese dioxide cathode using phthaloyl gelatin as a binder prepared in Example 1 of the present invention and the full cell assembled with cathode prepared in Comparative Example 1, after 1000 cycles at 10C.

[0089] Table 1

[0090] Table 2

[0091] As can be seen from Table 1, the manganese dioxide cathode prepared in Example 1 of this invention, using phthalated gelatin as a binder, exhibits superior rate performance compared to Comparative Example 1 after being assembled into a full cell. Even when the discharge rate is increased to 10C, it still maintains 279.1 mAh g⁻¹. -1 The specific capacity; when the discharge rate returns from a high rate of 10C to a low rate of 1C, the full cell capacity of Embodiment 1 of the present invention can also quickly recover to a higher specific capacity of 401.0 mAh g, which is higher than the initial specific capacity. -1 This fully demonstrates the structural stability of the cathode material and the reversibility of its internal reactions.

[0092] As can be seen from Table 2, the battery corresponding to Example 1 of the present invention exhibits superior cycle stability at a 10C rate, retaining a specific capacity of 288.5 mAh g after 1000 cycles. -1 During multiple charge-discharge cycles, the full battery assembled with a manganese dioxide cathode using phthalic acid gelatin as a binder exhibits lower capacity decay.

[0093] This invention prepares phthalyl gelatin and a manganese dioxide cathode using phthalyl gelatin as a binder. The phthalyl gelatin binder provides a highly resilient adhesive network, buffering volume change stress during cycling, thereby improving the battery's cycle performance. The acylation reaction introduces more free carboxyl groups, optimizing electrode-electrolyte wettability, constructing continuous zinc ion transport channels, and improving the battery's rate performance. Simultaneously, the good dispersibility, non-toxicity, and environmentally friendly properties of gelatin material enable green electrode manufacturing. This method can be used to design and fabricate highly safe zinc-ion batteries.

[0094] The present invention has been described above by way of example with reference to the embodiments and accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for preparing a phthalylated gelatin adhesive, characterized in that... Includes the following steps: Step 1: Add gelatin to a solvent to swell and dissolve, obtaining gelatin solution A. Adjust the pH of the system to 9.0 with an alkaline solution. Step 2 involves adding phthalic anhydride to the gelatin solution A obtained in Step 1 under water bath heating conditions, stirring magnetically, and continuously adding alkaline solution to maintain the pH of the system at 9.

0. After the pH of the system remains unchanged, the reaction continues to obtain solution B. Step 3: Transfer the solution B obtained in Step 2 to a dialysis bag, dialyze with deionized water, and finally freeze-dry the dialyzed product to obtain phthalic acid gelatin adhesive.

2. The method for preparing phthaloyl gelatin adhesive according to claim 1, characterized in that: In step 1, the mass fraction of gelatin solution A is 15-20%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-60℃.

3. The method for preparing phthaloyl gelatin adhesive according to claim 1, characterized in that: In step 2, the water bath heating temperature is 40-45℃, and the mass ratio of phthalic anhydride to gelatin added is 1:15-1:10; the reaction time is 20-40 minutes. The alkaline solution in steps 1 and 2 is a 7M NaOH solution.

4. The method for preparing phthaloyl gelatin adhesive according to claim 1, characterized in that: In step 3, the molecular weight cutoff of the dialysis bag is 200-500 Da, and the dialysis time is 48-72 h.

5. The application of a manganese dioxide positive electrode using phthalated gelatin as a binder as described in any one of claims 1-4 in a zinc-manganese battery, characterized in that: Electrochemical tests were conducted on a battery designed and assembled using a manganese dioxide cathode with phthalic acid gelatin as a binder.

6. The application of the phthaloyl gelatin adhesive of claim 5 in the manganese dioxide cathode of a zinc-ion battery, characterized in that... It includes the following steps: Step (1) The prepared phthalic acid gelatin adhesive is added to a solvent to swell and then dissolved to obtain phthalic acid gelatin solution C; Step (2) Mix β-manganese dioxide, KB carbon, and the phthalic acid gelatin solution C obtained in step (1) and stir magnetically to obtain a uniform positive electrode slurry; Step (3) The positive electrode slurry obtained in step (2) is coated onto the current collector and dried in a blower oven to obtain the positive electrode.

7. The application of the phthalylated gelatin adhesive according to claim 6 in the manganese dioxide cathode of a zinc-ion battery, characterized in that: In step (1), the mass fraction of phthalic acid gelatin solution C is 1-2%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-60℃.

8. The application of the phthaloyl gelatin adhesive according to claim 6 in the manganese dioxide cathode of a zinc-ion battery, characterized in that: In step (2), after mixing β-manganese dioxide, KB carbon, and phthalic acid gelatin solution C, the mass fraction of β-manganese dioxide is 60-70, the mass fraction of KB carbon is 20-30, the mass fraction of gelatin is 10-15, and the magnetic stirring time is 8-12 hours.

9. The application of the phthaloyl gelatin adhesive according to claim 6 in the manganese dioxide positive electrode of a zinc-ion battery, characterized in that: In step (3), the temperature of the forced-air drying oven is 40-60℃, and the β-manganese dioxide loading on the current collector should be controlled at 1-2 mg / cm³. -2 .

10. A manganese dioxide positive electrode for a zinc-ion battery, characterized in that: It is prepared using phthalic acid gelatin as described in any one of claims 1-4 as an adhesive.

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