A positive electrode with an integrated positive electrode / gel electrolyte structure, its preparation method and application

Abstract

The application relates to a positive electrode with a positive electrode / gel electrolyte integrated structure and a preparation method and application thereof, which is prepared by mixing beta-type manganese dioxide (beta-MnO2), conductive carbon and a gelatin solution to obtain uniform positive electrode slurry; the positive electrode slurry is scraped and coated on a current collector to form a gel, thereby obtaining a manganese dioxide positive electrode; then, a gel layer is prepared on the positive electrode by using gelatin, and then the positive electrode is soaked in an electrolyte for a certain time, and the positive electrode with the positive electrode / gel electrolyte integrated structure is obtained. The application constructs a positive electrode / gel electrolyte high-efficiency reaction interface, reduces the polarization phenomenon of ions in the transmission process, and improves the cycle stability of the battery; the gelatin-based hydrogel is used to integrate the positive electrode and the electrolyte, thereby improving the electrochemical reaction kinetics of the battery; meanwhile, the gelatin material has good dispersibility, non-toxicity and environment-friendly characteristics, so that the process is green. The method can be applied to design and prepare a flexible wearable battery with high safety.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and particularly relates to a positive electrode with an integrated positive electrode / gel electrolyte structure, its preparation method and application. Background Technology

[0002] In today's era of rapid technological development, emerging electronic products such as wearable devices and flexible electronic devices are experiencing explosive growth, creating an urgent need for flexible power sources. This has made zinc-manganese batteries a focus of research in the field of flexible power sources.

[0003] In traditional flexible zinc-manganese battery structures, the interface between the gel-based or polymer-based electrolyte and the positive electrode is poor. During frequent bending and stretching deformations of the flexible battery, it is prone to cracking and delamination, which can lead to internal short circuits and pose a significant threat to battery performance and safety. Furthermore, the presence of traditional gel-based or polymer-based electrolytes inevitably increases the thickness and weight of the battery, which is detrimental to the pursuit of ultra-thin and portable flexible electronic devices, thus limiting the application of flexible zinc-manganese batteries. Summary of the Invention

[0004] To overcome the series of problems that arise at the interface between the cathode and gel electrolyte in traditional zinc-manganese batteries under flexible application scenarios, this invention provides a method for preparing a cathode with an integrated cathode / gel electrolyte structure and its application.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a positive electrode with an integrated positive electrode / gel electrolyte structure includes the following steps:

[0007] Step 1: Preparation of the positive electrode

[0008] 1.1 Gelatin is added to a solvent to swell and then dissolved to obtain gelatin solution A;

[0009] 1.2 Mix β-MnO2, KB carbon, and gelatin solution A obtained in step 1.1, and stir magnetically to obtain a uniform positive electrode slurry;

[0010] 1.3 The positive electrode slurry obtained in step 1.2 is coated onto the current collector and gelled to obtain the positive electrode;

[0011] Step 2: Preparation of the positive electrode with an integrated positive electrode / gel electrolyte structure

[0012] 2.1 Gelatin is added to a solvent to swell and then dissolved to obtain gelatin solution B;

[0013] 2.2 The gelatin solution B obtained in step 2.1 is coated onto the positive electrode obtained in step 1.3, and then gelled;

[0014] 2.3 Immerse the positive electrode from step 2.2 in the electrolyte to obtain the positive electrode with the integrated positive electrode / gel electrolyte structure.

[0015] Furthermore, in step 1.1, the mass fraction of gelatin solution A is 1%-4%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-70℃.

[0016] Furthermore, in step 1.2, after mixing β-MnO2, KB carbon, and gelatin solution A, the mass fraction of β-MnO2 is 55-75, the mass fraction of KB carbon is 20-35, the mass fraction of gelatin is 5-10, and the magnetic stirring time is 10-15 hours.

[0017] Furthermore, in step 1.3, the thickness of the slurry coating is 200μm-300μm, and the β-MnO2 loading is 0.8-3mg.

[0018] Furthermore, in step 2.1, the mass fraction of gelatin solution B is 5%-12%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolution temperature is 50-70℃.

[0019] Furthermore, in step 2.2, the amount of gelatin solution applied is 150-350 μL.

[0020] Furthermore, in step 2.3, the electrolyte used for soaking is a 1-2.5M ZnSO4 + 0.1-0.5M MnSO4 solution, the amount of electrolyte used is 5ml-20ml, and the soaking time is 2-8h.

[0021] The present invention also discloses a positive electrode with an integrated positive electrode / gel electrolyte structure, which is prepared according to the above preparation method.

[0022] This invention also discloses the application of a positive electrode with an integrated positive electrode / gel electrolyte structure in a zinc-manganese battery, and the design and assembly of a battery using the positive electrode with the integrated positive electrode / gel electrolyte structure for electrochemical testing.

[0023] In the application of this invention, the specific assembly operation of the zinc-manganese full battery is as follows:

[0024] The process involves placing a standard Zn negative electrode inside a molded battery, then using plastic tweezers to gently place the prepared positive electrode / gel electrolyte, with the electrolyte side facing up, onto the Zn negative electrode, ensuring that the positive electrode and Zn negative electrode are aligned and that the electrolyte and Zn negative electrode are in flat contact. Finally, the battery is encapsulated to obtain a zinc-manganese full battery with an integrated positive electrode / gel electrolyte structure.

[0025] The positive electrode with an integrated positive electrode / gel electrolyte structure prepared by this invention has superior performance:

[0026] After assembling the zinc-manganese full battery, the positive electrode with an integrated positive electrode / gel electrolyte structure prepared using the examples exhibits good cycle stability. After 200 cycles at a 2C charge-discharge rate, its specific capacity still reaches 217.7 mAh g⁻¹. -1 The Coulomb efficiency is close to 100%.

[0027] These results demonstrate that the prepared cathode / gel electrolyte integrated structure exhibits superior electrochemical performance in zinc-manganese full battery systems.

[0028] During charge and discharge at a 2C rate, the high capacity retention demonstrates the structural stability and resistance to capacity decay. This is attributed to the continuous, integrated bonding between the gelatin binder in the positive electrode and the gelatin-based hydrogel electrolyte, which effectively reduces the loss of active material due to structural changes or side reactions during charge and discharge.

[0029] The high coulombic efficiency further confirms that the cathode / gel electrolyte integrated structure can achieve highly efficient electrochemical reversibility, with the electrons participating in the reaction being effectively utilized and minimal energy loss occurring during charge transfer.

[0030] The cathode / gel electrolyte integrated structure prepared in this invention exhibits excellent cycle performance, the mechanism of which is as follows:

[0031] Gelatin binder constructs a highly stable integrated structure between the positive electrode and the gelatin-based hydrogel electrolyte. The abundant functional groups on the gelatin molecular chain form strong interactions with ions in the electrolyte. The gel network formed by gelatin can effectively fix and disperse the positive electrode active material. During long-term cycling, it greatly inhibits the dissolution, migration, and aggregation of the active material. During battery cycling, the gelatin-based material has certain flexibility and self-healing properties, and can self-repair through intermolecular interactions, ensuring the stability of the integrated structure of the positive electrode and electrolyte, thereby ensuring the continuity of ion transport.

[0032] The present invention has the following beneficial effects:

[0033] 1. The positive electrode with an integrated positive electrode / gel electrolyte structure prepared by the present invention creates an extremely stable positive electrode / gel electrolyte interface, reduces the polarization phenomenon of ions during transport, and thus improves the cycle performance of the battery.

[0034] 2. The positive electrode prepared by this invention has an integrated positive electrode / gel electrolyte structure, which reduces the problems such as defects that may be introduced due to the interface between the two, and improves the electrochemical reaction efficiency of the battery.

[0035] 3. The positive electrode with an integrated positive electrode / gel electrolyte structure prepared by this invention ensures its safety in flexible batteries due to the excellent physicochemical properties and environmental friendliness of gelatin material. Attached Figure Description

[0036] The following is a further explanation with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the process for preparing the positive electrode with an integrated positive electrode / gel electrolyte structure according to Example 1 of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] 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.

[0040] Unless otherwise specified, all reagents and raw materials used in this invention can be purchased from the market.

[0041] In this invention, KB carbon is Ketjen Black, model EC-600JD.

[0042] Example 1

[0043] Preparation of cathodes with integrated positive electrode / gel electrolyte structure

[0044] Step 1: Accurately weigh 0.2g of gelatin and 9.8g of deionized water, swell at room temperature (20℃) for 5 minutes, and then dissolve completely in a 60℃ water bath to obtain gelatin solution A;

[0045] Step 2: Mix 0.36g β-MnO2, 0.18g KB carbon, and 3g gelatin solution A. To facilitate magnetic stirring, add 2.5ml deionized water and stir magnetically for 12h to obtain a uniform positive electrode slurry.

[0046] Step 3: Apply the positive electrode slurry obtained in Step 2 onto the current collector, with a coating thickness of 250 μm.

[0047] Step 4: Accurately weigh 0.5g of gelatin and 4.5g of deionized water, swell at room temperature (20℃) for 20 minutes, then place in a 60℃ water bath to dissolve completely, and sonicate for 3 minutes to remove air bubbles to obtain gelatin solution B.

[0048] Step 5: Take 250 μl of gelatin solution B and apply it to the positive electrode obtained in step 3 to form a gel.

[0049] Step 6: Immerse the positive electrode from Step 5 in 10 ml of 2 M ZnSO4 + 0.2 M N SO4 electrolyte, and remove it after 6 h to obtain a positive electrode with an integrated positive electrode / gel electrolyte structure.

[0050] The above-mentioned positive electrode with integrated positive electrode / gel electrolyte structure was assembled with a common zinc sheet negative electrode to form a battery, and then the cycle performance was tested after standing.

[0051] The various properties obtained by the present invention will be further illustrated with reference to the accompanying drawings:

[0052] from Figure 1 As can be seen, the positive electrode with an integrated positive electrode / gel electrolyte structure prepared in Example 1 of the present invention exhibits a complete integrated structure between the gel hydrogel and the positive electrode, and the gel electrolyte can be stably attached to the surface of the positive electrode and successfully eliminate the interface.

[0053] Example 2

[0054] Preparation of cathodes with integrated positive electrode / gel electrolyte structure

[0055] Step 1: 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 gelatin solution A;

[0056] Step 2: Mix 0.33g β-MnO2, 0.21g KB carbon, and 6g gelatin solution A, and stir magnetically for 10h to obtain a uniform positive electrode slurry;

[0057] Step 3: Apply the positive electrode slurry obtained in Step 2 onto the current collector to form a gel with a coating thickness of 200 μm.

[0058] Step 4: Accurately weigh 0.25g of gelatin and 4.75g of deionized water, swell at 10℃ for 30min, then place in a 50℃ water bath to dissolve completely, and sonicate for 3min to remove air bubbles to obtain gelatin solution B.

[0059] Step 5: Transfer 150 μl of gelatin solution B to the positive electrode obtained in step 3 and allow it to gel.

[0060] Step 6: Immerse the electrode from Step 5 in 5 ml of 1 M ZnSO4 + 0.1 M MnSO4 electrolyte, and remove it after 2 hours to obtain the positive electrode with the integrated positive electrode / gel electrolyte structure.

[0061] The above-mentioned positive electrode with an integrated positive electrode / gel electrolyte structure was assembled with a common zinc sheet negative electrode to form a battery, and then subjected to cycle performance testing after being left to stand. The battery assembled in Example 2 of this invention exhibits superior cycle stability at a 2C rate, and its capacity decay is lower than that of batteries assembled with a common PVDF positive electrode / gelatin hydrogel electrolyte during multiple charge-discharge cycles.

[0062] Example 3

[0063] Preparation of cathodes with integrated positive electrode / gel electrolyte structure

[0064] Step 1: Accurately weigh 0.4g of gelatin and 9.6g of deionized water, swell at 38℃ for 15min, and then dissolve completely in a 70℃ water bath to obtain gelatin solution A;

[0065] Step 2: Mix 0.45g β-MnO2, 0.12g KB carbon, and 0.75g gelatin solution A. To facilitate magnetic stirring, add 4ml deionized water and stir magnetically for 10h to obtain a uniform positive electrode slurry.

[0066] Step 3: Apply the positive electrode slurry obtained in Step 2 onto the current collector, with a coating thickness of 300 μm.

[0067] Step 4: Accurately weigh 0.6g of gelatin and 4.4g of deionized water, swell at 38℃ for 30min, then dissolve completely in a 70℃ water bath, and sonicate for 3min to remove air bubbles to obtain gelatin solution B.

[0068] Step 5: Transfer 350 μl of gelatin solution B to the positive electrode obtained in step 3 and allow it to gel.

[0069] Step 6: Immerse the positive electrode from Step 5 in 20 ml of 2.5 M ZnSO4 + 0.5 M NnSO4 electrolyte, and remove it after 8 hours to obtain the positive electrode with the integrated positive electrode / gel electrolyte structure.

[0070] The above-mentioned positive electrode with an integrated positive electrode / gel electrolyte structure was assembled with a common zinc sheet negative electrode to form a battery, and then subjected to cycle performance testing after being left to stand. The battery assembled in Example 3 of this invention exhibited superior cycle stability at a 2C rate, and its capacity decay was lower than that of batteries assembled with a common PVDF positive electrode / gelatin hydrogel electrolyte during multiple charge-discharge cycles.

[0071] Comparative Example 1

[0072] Preparation of ordinary PVDF cathode / gelatin hydrogel electrolyte

[0073] Step 1: Accurately weigh 0.1g PVDF and 9.9g NMP, mix them, and then magnetically stir at room temperature (20℃) for 8 hours to obtain a homogeneous solution;

[0074] Step 2: Mix 0.35g β-MnO2, 0.1g KB carbon, and 5g PVDF solution, add 2.5ml NMP, and stir magnetically for 12h to obtain a uniform positive electrode slurry;

[0075] Step 3: Apply the positive electrode slurry obtained in Step 2 onto the current collector, with a coating thickness of 250 μm.

[0076] Step 4: Accurately weigh 0.5g of gelatin and 4.5g of deionized water, swell at 20℃ for 20min, then place in a 60℃ water bath to dissolve completely, and sonicate for 3min to remove air bubbles to obtain a gelatin solution.

[0077] Step 5: Transfer 200 μl of the gelatin solution from Step 4 to the positive electrode sheet from Step 3 to form a gel.

[0078] Step 6: Immerse the electrode from Step 5 in 10 ml of 2MZnSO4 + 0.2MnSO4 electrolyte, and remove it after 6 hours to obtain the ordinary PVDF positive electrode / gelatin hydrogel electrolyte material.

[0079] Table 1 shows the rate performance of the zinc-manganese full cell with an integrated positive electrode / gel electrolyte structure prepared in Example 1 of the present invention and the full cell with a positive electrode prepared in Comparative Example 1 at 0.5C-5C, with each rate being 10 cycles.

[0080] Table 2 shows the long-cycle performance of the zinc-manganese full cell with an integrated positive electrode / gel electrolyte structure prepared in Example 1 of the present invention and the positive electrode assembled full cell prepared in Comparative Example 1 at 2C.

[0081] Table 1

[0082]

[0083] Table 2

[0084]

[0085] As can be seen from Table 1, the positive electrode with an integrated positive electrode / gel electrolyte structure prepared in Example 1 of this invention exhibits superior rate performance compared to Comparative Example 1 after being assembled into a full cell. Even when the discharge rate is increased to 5C, it can still maintain 150 mAh g⁻¹. -1 The specific capacity; when the discharge rate returns from a high rate of 5C to a low rate of 1C, the full battery capacity of Embodiment 1 of the present invention can also quickly recover to 280mAh g. -1This fully demonstrates the structural stability of the cathode material and the reversibility of its internal reactions.

[0086] As can be seen from Table 2, the battery corresponding to Example 1 of the present invention exhibits superior cycle stability at a 2C rate, with a specific capacity of 217.7 mAh g after 200 cycles. -1 During multiple charge-discharge cycles, batteries with an integrated positive electrode / gel electrolyte structure exhibit lower capacity decay.

[0087] This invention features a positive electrode / gel electrolyte integrated structure, creating an extremely stable integrated structure that reduces ion polarization during transport, thereby improving battery cycle performance. Gelatin-based hydrogels are used to enhance the battery's electrochemical reaction efficiency. Furthermore, the good dispersibility, non-toxicity, and environmental friendliness of gelatin materials make this process green. This method can be used to design and fabricate highly safe, flexible wearable batteries.

[0088] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using 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 positive electrode with an integrated positive electrode / gel electrolyte structure, characterized in that, Comprising the following steps: Step 1: Preparation of the positive electrode 1.1 Swell and dissolve the gelatin in the solvent to obtain gelatin solution A; 1.2 Mix β-MnO2, KB carbon and the gelatin solution A obtained in step 1.1, and magnetically stir to obtain a uniform positive electrode slurry; 1.3 Coat the positive electrode slurry obtained in step 1.2 on the current collector, and gel to obtain the positive electrode; Step 2: Preparation of the positive electrode with positive electrode / gel electrolyte integrated structure of zinc-manganese battery 2.1 Swell and dissolve the gelatin in the solvent to obtain gelatin solution B; 2.2 Apply the gelatin solution B prepared in step 2.1 to the positive electrode obtained in step 1.3 to form a gel; 2.3 Soak the positive electrode in step 2.2 in an electrolyte to obtain the positive electrode with positive electrode / gel electrolyte integrated structure.

2. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 1.1, the mass fraction of gelatin solution A is 1%-4%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolving temperature is 50-70℃.

3. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 1.2, after mixing β-MnO2, KB carbon and gelatin solution A, the mass fraction of β-MnO2 is 55-75, the mass fraction of KB carbon is 20-35, the mass fraction of gelatin is 5-10, and the magnetic stirring time is 10h-15h.

4. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 1.3, the thickness of the slurry coating is 200μm-300μm, and the β-MnO2 loading is 0.8-3mg.

5. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 2.1, the mass fraction of gelatin solution B is 5%-12%, the solvent is deionized water, the swelling temperature is 10-38℃, and the dissolving temperature is 50-70℃.

6. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 2.2, the amount of gelatin solution removed is 150-350ul.

7. The preparation method of the positive electrode with positive electrode / gel electrolyte integrated structure according to claim 1, characterized in that: In step 2.3, the electrolyte used for soaking is a 1-2.5MZnSO4+0.1-0.5MMnSO4 solution, the amount of electrolyte used is 5ml-20ml, and the soaking time is 2-8h.

8. A positive electrode having a positive electrode / gel electrolyte integrated structure, characterized by: It is prepared according to the preparation method of any one of claims 1-7.

9. The application of the positive electrode with positive electrode / gel electrolyte integrated structure in a zinc-manganese battery according to claim 8, characterized in that: The positive electrode with positive electrode / gel electrolyte integrated structure is designed and assembled into a battery for electrochemical testing.

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