Gelatin-based carbon dot composite and preparation method and application thereof
By using gelatin-based carbon dot composites as positive electrode binders, the problems of high positive electrode impedance and structural instability in aqueous zinc-manganese dioxide batteries were solved, achieving high-efficiency battery cycle performance and long battery life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2024-12-31
- Publication Date
- 2026-07-10
AI Technical Summary
Existing aqueous zinc-manganese dioxide batteries suffer from high positive electrode impedance and structural instability, resulting in poor battery cycle performance.
Gelatin-based carbon dot composites were used as positive electrode binders. The gelatin-based carbon dot composites were prepared by hydrothermal method and mixed with manganese dioxide and conductive agents to form a network structure, which enhanced the mechanical strength and ion transport channels of the positive electrode.
Gelatin-based carbon dot composites reduce the internal impedance of the positive electrode, improve the stability of the electrode structure and the cycle performance of the battery, ensure efficient high-rate charging and discharging, and extend the charge-discharge cycle life of the battery.
Smart Images
Figure CN120015832B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrode technology, specifically relating to a gelatin-based carbon dot composite, its preparation method, and its application. Background Technology
[0002] As the global energy mix shifts towards renewable energy, the demand for energy storage is increasing, creating an urgent need for efficient and economical energy storage technologies. While lithium-ion batteries (LIBs) are a mature energy storage technology, they face significant challenges in terms of raw material supply, safety, and cost. Therefore, neutral aqueous zinc-ion batteries (AZIBs) have emerged as a promising option due to their safety and the high theoretical volumetric energy density of the zinc metal anode.
[0003] Among the various cathode materials developed for AZlB, manganese dioxide (MnO2) is an ideal electrode material and has been extensively studied due to its high theoretical energy density. However, challenges remain for aqueous zinc-manganese dioxide batteries (Zn-MnO2). Summary of the Invention
[0004] To overcome the above problems, this invention provides a gelatin-based carbon dot composite, its preparation method, and its application. The gelatin-based carbon dot composite, as a positive electrode binder, is beneficial for reducing positive electrode impedance. The polymer can form a network structure, which helps maintain the stability of the positive electrode structure. The electrode prepared from this composite exhibits high specific capacity and excellent cycle stability.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A method for preparing a gelatin-based carbon dot complex includes the following steps:
[0007] Step 1: Add gelatin to a solvent to swell and dissolve, obtaining a gelatin solution;
[0008] Step 2: Place the gelatin solution obtained in Step 1 into a hydrothermal reactor, keep it warm, and then remove it to obtain the hydrothermally heated product solution;
[0009] Step 3: Place the hydrothermal product obtained in Step 2 into a centrifuge, centrifuge, and remove the supernatant.
[0010] Step 4: Dry the product obtained in step 3 to obtain the gelatin-based carbon dot composite.
[0011] Furthermore, in step 1, the mass fraction of gelatin is 3%-10%, the solvent is deionized water, the swelling temperature is 10-28℃, and the dissolution temperature is 45-65℃.
[0012] In step 2, the hydrothermal insulation temperature is 150-240℃, and the insulation time is 3-10h.
[0013] Furthermore, in step 3, the centrifugation speed is 5000-10000 r / min, and the centrifugation time is 5 min-20 min.
[0014] Furthermore, in step 4, the drying method is either freeze drying or oven drying.
[0015] The present invention also discloses a gelatin-based carbon dot composite, which is prepared according to the above preparation method.
[0016] This invention also discloses the application of the above-mentioned gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries. The positive electrode is designed and prepared using the gelatin-based carbon dot composite as a binder, and a zinc-manganese full cell is assembled for electrochemical testing.
[0017] Furthermore, the application of the above-mentioned gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries includes the following steps:
[0018] Manganese dioxide, conductive agent and gelatin-based carbon dot complex were mixed evenly and magnetically stirred to prepare positive electrode slurry.
[0019] The positive electrode slurry is coated onto titanium foil, dried, and then cut into round pieces to serve as the positive electrode of the button cell.
[0020] The above positive electrode sheet was assembled with a common zinc negative electrode and a glass fiber separator to form a CR2025 button cell. After standing, the cycle performance was tested.
[0021] Furthermore, the gelatin-based carbon dot composite accounts for 5%-20% of the mass fraction in the positive electrode slurry, the magnetic stirring speed is 300-600 r / min, and the stirring time is 10h-15h.
[0022] Furthermore, the mass ratio of the manganese dioxide, conductive agent, and gelatin-based carbon dot composite is 6-8:1.5-2:0.5-2.
[0023] Furthermore, the conductive agent is one of Ketjen Black (KB), acetylene black (AB), and conductive carbon black (Super P).
[0024] The gelatin-based carbon dot composite prepared in this invention exhibits superior performance as a positive electrode binder:
[0025] After assembling a zinc-manganese full cell using the cathode prepared above, it showed no significant capacity decay after 500 cycles at a 5C charge-discharge rate, and the capacity remained stable at 300 mAh g⁻¹. -1 about.
[0026] These results demonstrate that the gelatin-based carbon dot composite prepared in this invention exhibits significant advantages as a positive electrode binder in zinc-manganese battery applications, and the composite imparts extremely high structural stability to the positive electrode.
[0027] During high-rate charging and discharging, the stress changes and volume effects caused by ion insertion and extraction on the electrode material did not cause substantial damage to the overall structure of the electrode. The network structure formed by the polymer in the gelatin carbon dot composite effectively maintained the integrity and stability of the electrode structure, preventing the shedding of active materials and structural collapse, thereby ensuring the stable output of battery capacity.
[0028] The gelatin-based carbon dot composite prepared in this invention, when used as a positive electrode binder, enables the manganese dioxide positive electrode to exhibit excellent cycle performance. The mechanism is as follows:
[0029] Gelatin-based carbon dot composites reduce the internal impedance of the positive electrode, minimize polarization, and ensure efficient battery charging and discharging reactions.
[0030] The network structure formed by the polymer layer in the gelatin-based carbon dot composite binder not only enhances the mechanical strength of the electrode but also provides a stable channel for ion transport. This network structure effectively disperses and fixes the active material, further improving the stability of the active material in the electrode.
[0031] The present invention has the following beneficial effects:
[0032] 1. The gelatin-based carbon dot composite binder for high-performance zinc-manganese battery cathodes prepared in this invention exhibits high performance in batteries under high-rate charge and discharge conditions due to its excellent ion-conducting properties.
[0033] 2. The gelatin-based carbon dot composite binder for high-performance zinc-manganese battery cathode prepared in this invention imparts structural stability to the cathode, resulting in minimal capacity decay during long-term cycling and improving the charge-discharge cycle life of the battery. Attached Figure Description
[0034] The following explanation, in conjunction with the accompanying drawings, will provide further details.
[0035] Figure 1 TEM image of the gelatin-based carbon dot composite binder for high-performance zinc-manganese battery cathode prepared in Example 1 of this invention.
[0036] Figure 2 Electrochemical impedance spectroscopy of the gelatin-based carbon dot composite for the high-performance zinc-manganese battery cathode prepared in Example 1 of the present invention and the battery assembled in Comparative Example 1. Detailed Implementation
[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0038] 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.
[0039] Unless otherwise specified, all reagents and raw materials used in this invention can be purchased from the market.
[0040] Explanation of several conductive agents: The conductive agents used in this invention are Ketjen Black (KB), acetylene black (AB), and conductive carbon black (Super P).
[0041] Example 1
[0042] Preparation of gelatin-based carbon dot complexes:
[0043] Step 1: Swell the gelatin in a 5% (w / w) gelatin solvent at 25°C, then dissolve it at 60°C to obtain a gelatin solution.
[0044] Step 2: Place the mixed solution obtained in Step 1 into a hydrothermal reactor, keep it at 180℃ for 6 hours, and then take it out to obtain the hydrothermal product liquid;
[0045] Step 3: Place the hydrothermally heated solution obtained in Step 2 into a centrifuge, centrifuge at 8000 r / min for 10 min, and then remove the supernatant.
[0046] Step 4: Dry the product obtained in Step 3 to obtain the gelatin-based carbon dot composite.
[0047] Manganese dioxide, conductive agent (KB) and gelatin-based carbon dot composite were mixed evenly at a mass ratio of 7:2:1 and magnetically stirred at 500 r / min for 12 h to obtain positive electrode slurry.
[0048] The positive electrode slurry is coated onto titanium foil, dried, and then cut into round pieces to serve as the positive electrode of a button cell.
[0049] The above-mentioned positive electrode sheet was assembled with a common zinc negative electrode sheet and a glass fiber separator to form a CR2025 button cell. After being left to stand, a cycle performance test was conducted.
[0050] Example 2
[0051] Step 1: Swell the gelatin in a 10% (w / w) gelatin solvent at 28°C, then dissolve it at 65°C to obtain a gelatin solution.
[0052] Step 2: Place the gelatin solution obtained in Step 1 into a hydrothermal reactor, keep it at 240℃ for 3 hours, and then take it out to obtain the hydrothermally heated product solution.
[0053] Step 3: Place the hydrothermal product obtained in Step 2 into a centrifuge, centrifuge at 10000 r / min for 5 min, and then take out the supernatant.
[0054] Step 4: Dry the product obtained in Step 3 to obtain the gelatin-based carbon dot composite.
[0055] Manganese dioxide, conductive agent (AB) and gelatin-based carbon dot composite were mixed evenly in a mass ratio of 6:2:2 and magnetically stirred at 600 r / min for 10 h to obtain positive electrode slurry.
[0056] The positive electrode slurry is coated onto titanium foil, dried, and then cut into round pieces to serve as the positive electrode of the button cell.
[0057] The above positive electrode sheet was assembled with a common zinc negative electrode and a glass fiber separator to form a CR2025 button cell. After standing, the cycle performance was tested.
[0058] Example 3:
[0059] Step 1: Swell the gelatin in a 3% (w / w) gelatin solvent at 10°C, then dissolve it at 45°C to obtain a gelatin solution.
[0060] Step 2: Place the gelatin solution obtained in Step 1 into a hydrothermal reactor, keep it at 150℃ for 10 hours, and then take it out to obtain the hydrothermally heated product solution.
[0061] Step 3: Place the hydrothermally heated solution obtained in Step 2 into a centrifuge, centrifuge at 5000 r / min for 20 min, and then remove the supernatant.
[0062] Step 4: Freeze-dry the product obtained in Step 3 to obtain the gelatin-based carbon dot composite.
[0063] Manganese dioxide, conductive agent (Super P) and gelatin-based carbon dot composite were mixed evenly at a mass ratio of 8:1.5:0.5 and magnetically stirred at 300 r / min for 15 h to obtain positive electrode slurry.
[0064] The positive electrode slurry is coated onto titanium foil, dried, and then cut into round pieces to serve as the positive electrode of the button cell.
[0065] The above positive electrode sheet was assembled with a common zinc negative electrode and a glass fiber separator to form a CR2025 button cell. After standing, the cycle performance was tested.
[0066] Regarding the assembly of zinc-manganese batteries
[0067] In Example 1:
[0068] Manganese dioxide, conductive agent and gelatin-based carbon dots are mixed in a mass ratio of 7:2:1 and magnetically stirred for a certain time to obtain a positive electrode slurry. The slurry is then coated onto titanium foil, dried, and cut into 12mm round pieces to serve as the positive electrode of a button cell.
[0069] The above positive electrode sheet, together with a common zinc negative electrode and a glass fiber separator, are assembled into a CR2025 button cell. The electrolyte is 2M ZnSO4 plus 0.2M MnSO4. The assembled cell is left to stand for 8 hours.
[0070] Electrochemical performance testing of zinc-manganese batteries
[0071] Cyclic performance tests were conducted on zinc-manganese batteries using a charge-discharge device.
[0072] In Example 2, the mass ratio of manganese dioxide, conductive agent and gelatin-based carbon dot complex was 6:2:2; other operations were the same as in Example 1.
[0073] In Example 3, the mass ratio of manganese dioxide, conductive agent and gelatin-based carbon dot complex was 8:1.5:0.5; other operations were the same as in Example 1.
[0074] The gelatin-based carbon dot composite for high-performance zinc-manganese battery cathode prepared using Example 1 exhibits high performance, with a specific capacity of approximately 300 mAh g after 500 cycles at 5C in assembled full cells. -1 .
[0075] pass Figure 1 Further explanation of Example 1:
[0076] from Figure 1 It can be seen that the gelatin-based carbon dot complex was successfully synthesized, and the quantum dots are uniformly distributed in the complex as shown in the TEM image.
[0077] from Figure 2 It can be seen that the battery assembled with gelatin-based carbon dot composite as positive electrode binder has lower impedance than the battery assembled with PVDF as positive electrode binder.
[0078] As can be seen from Table 1, the electrode prepared with gelatin-based carbon dot composite as positive electrode binder has superior rate performance compared with the electrode prepared with PVDF as positive electrode binder.
[0079] As shown in Table 2, the electrode prepared using gelatin-based carbon dot composite as the positive electrode binder exhibits higher specific capacity and longer cycle stability compared to the electrode prepared using PVDF as the positive electrode binder, achieving a capacity of 307.2 mAh g⁻¹ after 500 cycles at 5C. 1 High specific capacity; under the same conditions, the specific capacity of the PVDF cathode is only 154 mAh g- 1 .
[0080] The gelatin-based carbon dot composite binder prepared in Example 2 for use in high-performance zinc-manganese battery cathodes exhibits excellent performance, with a specific capacity of 270.3 mAh g after 500 cycles at 5C on assembled full cells. -1 .
[0081] The gelatin-based carbon dot composite for high-performance zinc-manganese battery cathode prepared using Example 3 exhibits excellent electrochemical performance, with a specific capacity of approximately 247.8 mAh g after 500 cycles at 5C in a fully assembled cell. -1 .
[0082] The gelatin-based carbon dot composite prepared in Comparative Example 1, used as a cathode binder for high-performance zinc-manganese batteries, exhibits high performance, achieving a specific capacity of 154 mAh g⁻¹ after 500 cycles at 5C for assembled full cells. 1 .
[0083] For details on the electrical performance of the assembled zinc-manganese full cell in Example 1, please refer to Tables 1 and 2:
[0084] Table 1 shows the rate performance results of the zinc-manganese full cell assembled with the gelatin-based carbon dot composite binder for the high-performance zinc-manganese battery cathode prepared in Example 1 of the present invention.
[0085] Table 2 shows the long-cycle performance of the zinc-manganese full cell assembled with the gelatin-based carbon dot composite binder for the high-performance zinc-manganese battery cathode prepared in Example 1 of the present invention at 5C, as shown in Table 1.
[0086] Table 1. Summary of Zinc-Manganese Battery Rate Performance Test Results
[0087]
[0088] Table 25C Cycle Performance Test Results of Zinc-Manganese Batteries
[0089]
[0090] Table 1 shows that the electrode prepared using gelatin-based carbon dot composite as a binder exhibits superior rate performance compared to the control group (electrode prepared using PVDF as a binder). Table 2 shows that the electrode prepared using gelatin-based carbon dot composite as a binder has higher specific capacity and longer cycle stability compared to the control group.
[0091] The gelatin-based carbon dot composite binder for high-performance zinc-manganese battery cathodes prepared in this invention enables the battery to exhibit high performance under high-rate charge-discharge conditions. This gelatin-based carbon dot composite binder imparts structural stability to the cathode, resulting in minimal capacity decay during long-term cycling and a significant improvement in battery cycle performance.
[0092] 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. The application of a gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries, characterized in that: A positive electrode was designed and prepared using the gelatin-based carbon dot composite as a binder, and a zinc-manganese full cell was assembled for electrochemical testing. The gelatin-based carbon dot composite was prepared according to the following method: Step 1: Add gelatin to a solvent to swell and dissolve, obtaining a gelatin solution; Step 2: Place the gelatin solution obtained in Step 1 into a hydrothermal reactor, keep it warm, and then remove it to obtain the hydrothermally heated product solution; Step 3: Place the hydrothermal product obtained in Step 2 into a centrifuge, centrifuge, and remove the supernatant. Step 4: Dry the product obtained in Step 3 to obtain the gelatin-based carbon dot composite. In step 1, the mass fraction of gelatin is 3%-10%, the solvent is deionized water, the swelling temperature is 10-28℃, and the dissolution temperature is 45-65℃. In step 2, the hydrothermal insulation temperature is 150-240℃, and the insulation time is 3-10h. In step 3, the centrifugation speed is 5000-10000 r / min, and the centrifugation time is 5 min-20 min; In step 4, the drying method is either freeze drying or oven drying.
2. The application of the gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries according to claim 1, characterized in that, The specific operation includes the following steps: Manganese dioxide, conductive agent and gelatin-based carbon dot complex were mixed evenly and magnetically stirred to prepare positive electrode slurry. The positive electrode slurry is coated onto titanium foil, dried, and then cut into round pieces to serve as the positive electrode of the button cell. The above positive electrode was assembled with a common zinc sheet negative electrode and a glass fiber separator to form a CR2025 button cell. After standing, the cycle performance was tested.
3. The application of the gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries according to claim 2, characterized in that: The gelatin-based carbon dot composite is 5%-20% by mass in the positive electrode slurry, and the magnetic stirring speed is 300-600 r / min for 10-15 h.
4. The application of the gelatin-based carbon dot composite as a positive electrode binder in zinc-manganese batteries according to claim 2, characterized in that: The mass ratio of the manganese dioxide, conductive agent, and gelatin-based carbon dot composite is 6-8:1.5-2:0.5-2.
5. The application of the gelatin-based carbon dot composite according to claim 2 as a positive electrode binder in zinc-manganese batteries, characterized in that: The conductive agent is one of Ketjen black, acetylene black, and conductive carbon black.