An adaptive catalytic cathode for lithium-carbon dioxide batteries, its preparation method and application
The manganese oxide/manganese carbide composite material prepared by electrospinning, as the positive electrode of lithium-carbon dioxide battery, solves the problems of poor catalyst activity and conductivity, improves the energy efficiency and stability of the battery, simplifies the preparation process, and reduces costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2023-11-29
- Publication Date
- 2026-06-30
Smart Images
Figure CN117638102B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium-carbon dioxide batteries, specifically relating to an adaptive catalytic cathode for lithium-carbon dioxide batteries, its preparation method, and its application. Background Technology
[0002] With the continuous improvement of living standards and industrialization, global energy demand is surging, and humanity is facing the enormous challenge of simultaneously meeting this ever-increasing energy demand and reducing carbon emissions. In recent years, researchers have developed numerous methods and technologies for CO2 capture and utilization. Among them, lithium-carbon dioxide batteries, which use CO2 as the working gas, can simultaneously achieve CO2 utilization and conversion at room temperature, which is of positive significance for achieving the ambitious goal of net carbon emissions. Furthermore, the theoretical energy density of lithium-carbon dioxide batteries is as high as 1876 Wh / kg. -1 (More than 6 times that of lithium-ion batteries), lithium-carbon dioxide batteries also have great application potential in high-energy-density devices. However, current lithium-carbon dioxide batteries suffer from problems such as slow cathode reaction kinetics, high overpotential, low energy efficiency, and electrolyte decomposition, which limit the further development of the batteries. The core of these problems lies in the poor activity and selectivity of the cathode catalyst. Therefore, researchers have carried out a lot of research on cathode catalysts for lithium-carbon dioxide batteries.
[0003] Currently, common cathode catalysts in lithium-carbon dioxide batteries include noble metal catalysts, rare earth catalysts, transition metal catalysts, and composite catalysts with carbon-based materials. Among these, noble metals such as Pt and Ru exhibit excellent catalytic activity in lithium-carbon dioxide batteries due to their unique electronic configurations and high chemical stability; however, the high cost of noble metal catalysts severely limits their further large-scale application. Transition metal catalysts, with their advantages of low cost, abundant reserves, noble metal-like outer electrons, and rich defect and edge sites, are considered ideal candidates. Therefore, exploring low-cost, high-activity transition metal catalysts is of great significance for the application of lithium-carbon dioxide batteries. Manganese-based catalysts exhibit competitive catalytic activity as cathode catalysts in lithium-carbon dioxide batteries due to the abundant valence states and diverse crystal structures of manganese. However, current research mainly focuses on the design and synthesis of nanoparticle catalysts, which leads to three key issues: 1) low loading of cathode active materials, resulting in limited battery areal capacity; 2) catalysts used as battery cathodes require polymer binders, the addition of which not only leads to the loss of some active centers but also causes numerous side reactions due to their decomposition; 3) powdered catalysts require carbon paper, carbon cloth, nickel foam, etc., as supports, which complicates the battery fabrication process and reduces energy density. Summary of the Invention
[0004] The purpose of this invention is to provide an adaptive catalytic cathode for lithium-carbon dioxide batteries, its preparation method, and its application, in order to solve the problem of slow kinetics of CO2 reduction and Li2CO3 oxidation reactions during the charging and discharging process of lithium-carbon dioxide batteries, and to overcome the performance barriers of low battery energy efficiency, poor cycle stability, and limited full charge and full discharge capacity.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A method for preparing an adaptive catalytic cathode for lithium-carbon dioxide batteries includes the following steps:
[0007] 1) Add the manganese-based compound to N,N-dimethylformamide and stir until the manganese-based compound is completely dissolved to obtain solution A;
[0008] 2) Add polyacrylonitrile to solution A and stir at the first preset temperature to obtain ink B;
[0009] 3) Obtain a nanofiber membrane composed of polyacrylonitrile and manganese salt by electrospinning ink B;
[0010] 4) Vacuum dry the nanofiber membrane to obtain a dried nanofiber membrane;
[0011] 5) The dried nanofiber membrane is subjected to cyclization and oxidation treatment at a second preset temperature to obtain the treated nanofiber membrane;
[0012] 6) The treated nanofiber membrane was carbonized in an inert atmosphere to obtain an adaptive catalytic cathode for lithium-carbon dioxide batteries.
[0013] Furthermore, the manganese-based compound is manganese nitrate hexahydrate, manganese acetate, manganese chloride tetrahydrate, or manganese acetylacetone.
[0014] Furthermore, the molecular weight of the polyacrylonitrile is 50,000, 85,000, 150,000, or 250,000.
[0015] Further, the mass ratio of the manganese-based compound, N,N-dimethylformamide and polyacrylonitrile is (0.2-0.9):(5-14):(0.6-1.4).
[0016] Furthermore, magnetic stirring is used in both steps 1) and 2), with the stirring time in step 1) being 30 min and the stirring time in step 2) being 12 h, and the first preset temperature being 40-60℃.
[0017] Furthermore, the process parameters of the electrospinning method are as follows: temperature 30-60℃, average humidity 35-55%, positive high voltage 12-16KV, negative high voltage -2.5KV, receiving distance 10-20cm, roller speed 50-200r / min, and syringe translation speed 3mm / s.
[0018] Furthermore, in step 4), the vacuum drying temperature is 60-70℃ and the time is 10h;
[0019] In step 5), the second preset temperature is 210-300℃, and the cyclization and oxidation treatment time is 1-6h.
[0020] Furthermore, in step 6), the inert atmosphere is nitrogen or argon, the heating rate is 2-5℃ / min, the carbonization temperature is 700-900℃, and the isothermal holding time is 2h.
[0021] An adaptive catalytic cathode for lithium-carbon dioxide batteries is prepared using the method described above.
[0022] Application of an adaptive catalytic cathode for lithium-carbon dioxide batteries.
[0023] Compared with the prior art, the present invention has the following beneficial technical effects:
[0024] This invention utilizes the autocatalytic effect of manganese on graphitization to enhance the graphitization degree of carbon surrounding manganese during carbonization, thereby improving the conductivity of the electrode. This effectively solves the problem of poor conductivity of transition metal compounds during catalysis, improves the charge transfer of the positive electrode in lithium-carbon dioxide batteries, and effectively ensures the rate performance of the battery. The electrode obtained by this invention is a self-supporting catalytic positive electrode that can be directly used as the positive electrode of lithium-carbon dioxide batteries. It reduces the electrode coating and preparation process, avoids the use of binders and conductive carbon black, and can effectively reduce side reactions during battery charging and discharging and the production cost of the battery. In addition, the preparation process and technology of this invention are simple, the overall production cost is low, and it is easy to achieve large-scale production, which has positive significance for the commercialization of lithium-carbon dioxide batteries.
[0025] Furthermore, by optimizing the ink concentration and spinning parameters, this invention utilizes the advantages of electrospinning to construct a three-dimensional self-supporting nanofiber membrane, thereby constructing a three-dimensional self-supporting catalytic cathode with rapid mass transfer for lithium-carbon dioxide batteries. Attached Figure Description
[0026] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0027] Figure 1The image shows a physical sample of the polyacrylonitrile nanofiber membrane obtained by electrospinning in the comparative example.
[0028] Figure 2 This is a scanning electron microscope image of the nitrogen-doped carbon nanofiber self-supporting film obtained by carbonization in the comparative example.
[0029] Figure 3 This is a transmission electron microscope image of the nitrogen-doped carbon nanofiber self-supporting film obtained by carbonization in the comparative example.
[0030] Figure 4 This is a photograph of an acetylacetone-loaded polyacrylonitrile nanofiber membrane obtained by electrospinning in Example 1.
[0031] Figure 5 The image shows a scanning electron microscope image of manganese oxide-manganese carbide loaded onto a nitrogen-doped carbon nanofiber membrane (MOC@NCNF) obtained by carbonization in Example 1.
[0032] Figure 6 The image shows a transmission electron micrograph of MOC@NCNF obtained by carbonization in Example 1.
[0033] Figure 7 The X-ray diffraction pattern of MOC@NCNF obtained by carbonization in Example 1;
[0034] Figure 8 Comparison of cyclic voltammetry curves of lithium-carbon dioxide batteries based on MOC@NCNF and NCNF cathode catalysts in the application examples;
[0035] Figure 9 The lithium-carbon dioxide batteries based on MOC@NCNF and NCNF cathode catalysts, respectively, were used in the application examples at 20 μA / cm. -2 Comparison of full discharge and full charge performance at current density;
[0036] Figure 10 For the example application of a lithium-carbon dioxide battery based on the MOC@NCNF cathode catalyst at 50 μA cm⁻¹ -2 Current density, 100 μAh cm -2 Cyclic performance under cutoff capacity;
[0037] Figure 11 For the example application of a lithium-carbon dioxide battery based on the MOC@NCNF cathode catalyst at 50 μA cm⁻¹ -2 Current density, 200 μAh cm -2 Cyclic performance under cutoff capacity;
[0038] Figure 12 The graph shows the rate performance test results of a lithium-carbon dioxide battery based on the MOC@NCNF cathode catalyst in an application example. Detailed Implementation
[0039] The present invention will be explained in further detail below:
[0040] This invention uses polyacrylonitrile and different manganese salts as precursors, and constructs a three-dimensional self-supporting electrode for direct use in lithium-carbon dioxide batteries through electrospinning followed by staged carbonization. The interconnected three-dimensional structure constructed by electrospinning not only effectively promotes the Li-carbon dioxide exchange process in the battery... + The invention improves the conductivity of carbon fibers by enhancing CO2 mass transfer and, moreover, by inducing graphitization of surrounding carbon at manganese sites during carbonization. Through optimized preparation conditions, a three-dimensional self-supporting carbon fiber-supported manganese oxide / manganese carbide flexible electrode (MOC@NCNF) was developed, exhibiting both rapid mass and charge transfer characteristics. When applied to lithium-carbon dioxide batteries for catalyst reconstruction (adaptive), subsequent electrochemical performance tests showed that MOC@NCNF significantly promoted the reaction kinetics of CO2 reduction and Li2CO3 oxidation, reducing battery overpotential. Therefore, lithium-carbon dioxide batteries based on the MOC@NCNF cathode exhibited higher energy efficiency and cycle stability, effectively contributing to the commercial value and industrial promotion of lithium-carbon dioxide batteries.
[0041] Specifically, it includes the following steps:
[0042] (P1) Dissolve 200-900 mg of manganese-based compound in 5-14 g of N,N-dimethylformamide and stir magnetically for 30 min until the manganese-based compound is completely dissolved to obtain solution A.
[0043] The manganese-based compounds include manganese nitrate hexahydrate, manganese acetate, manganese chloride tetrahydrate, manganese acetylacetonate, etc., and preferably, manganese acetylacetonate is selected as the manganese-based compound.
[0044] (P2) Add 0.6-1.4g of polyacrylonitrile to solution A in (P1) and stir magnetically for 12h at 40-60℃ to obtain ink B.
[0045] The molecular weights of the polyacrylonitrile were selected as 50,000, 85,000, 150,000 and 250,000, respectively.
[0046] (P3) Take a certain amount of ink B into a 10mL syringe and obtain a nanofiber membrane composed of polyacrylonitrile and manganese salt by electrospinning.
[0047] The electrospinning process parameters are as follows: temperature 30-60℃, average humidity 35-55%, positive high voltage 12-16KV, negative high voltage -2.5KV, receiving distance 10-20cm, roller speed 50-200r / min, and syringe translation speed 3mm / s.
[0048] Preferably, the electrospinning process parameters are selected as follows: temperature 30℃, average humidity 40%, receiving distance 15cm, and roller speed 100r / min.
[0049] (P4) The nanofiber membrane in (P3) was dried in a vacuum oven at 60-70℃ for 10h.
[0050] (P5) The dried nanofiber membrane from (P4) was subjected to cyclization and oxidation treatment in a muffle furnace at 210-300℃ for 1-6 hours.
[0051] (P6) Carbonize the pre-oxidized nanofiber membrane in (P5) in an inert atmosphere to obtain the target lithium-carbon dioxide battery adaptive catalytic cathode.
[0052] The inert atmosphere is nitrogen or argon, the heating rate is 2-5℃ / min, the final temperature is 700-900℃, and the isothermal holding time is 2h.
[0053] Preferably, argon is selected as the inert atmosphere, and the heating rate is 5℃ / min.
[0054] (P7) Lithium-carbon dioxide battery assembly: Place the battery case, self-supporting catalytic positive electrode, separator, electrolyte, negative electrode, current collector, and battery case in sequence, and then encapsulate the battery.
[0055] (P8) Transfer the battery to a self-made test device, then introduce CO2 gas, and after standing for 8 hours, perform electrochemical performance tests. The electrochemical performance tests include cyclic voltammetry performance, full discharge-full charge performance, cycle performance at different current densities, and rate performance.
[0056] The present invention will be further explained in detail below with reference to the embodiments. The following embodiments are preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, the methods and experimental equipment used in the following embodiments are conventional methods and instruments. The experimental instruments used in the embodiments include an X-ray diffractometer (Bruker D8 ADVANC), a field emission scanning electron microscope (GeminiSEM 500), a Lorentz transmission electron microscope (Talos F200X), a simultaneous thermal analyzer (TGA / DSC3+), an electrochemical workstation (ParStat 4000), and a battery tester, etc.
[0057] Comparative Example
[0058] A method for preparing three-dimensional self-supporting nitrogen-doped carbon fiber (NCNF) includes the following steps:
[0059] (P1) Dissolve 1g of polyacrylonitrile with a molecular weight of 150,000 in 10g of N,N-dimethylformamide and stir magnetically at 55°C for 12h to obtain electrospinning ink.
[0060] (P2) The above ink was poured into a 10 mL syringe and polyacrylonitrile nanofiber membrane was prepared under the following conditions: temperature 30℃, average humidity 40%, positive pressure 14 kV, negative pressure -2.5 kV, receiving distance 15 cm, roller speed 100 r / min, and syringe translation speed 3 mm / s.
[0061] (P3) The nanofiber membrane in (P2) was dried in a vacuum oven at 60°C for 10 h.
[0062] (P4) The dried nanofiber membrane from (P3) was subjected to cyclization and oxidation treatment at 260°C for 2 hours in a muffle furnace.
[0063] (P5) The nanofiber membrane pre-oxidized in (P4) was heated to 840℃ in an argon atmosphere at a heating rate of 5℃ / min and held for 2h to obtain a self-supporting NCNF cathode for lithium-carbon dioxide batteries.
[0064] The physicochemical properties of NCNF were characterized: Figure 1 The polyacrylonitrile nanofiber membrane obtained by electrospinning shows that the membrane surface is uniform and it is easy to prepare large areas. Figure 2 The image shows a scanning electrochemical electron microscope image of carbonized NCNF. The image shows interconnected carbon nanofibers, which lay the foundation for mass and charge transfer. The diameter of the carbon nanofibers is about 300 nm. Figure 3 The image shows a transmission electron microscope image of NCNF; the fibers do not exhibit a distinct graphitized structure.
[0065] Example 1
[0066] A method for preparing an adaptive catalytic cathode for lithium-carbon dioxide batteries includes the following steps:
[0067] (P1) Dissolve 500 mg of manganese acetylacetonate in 10 g of N,N-dimethylformamide and stir magnetically for 30 min until the manganese acetylacetonate is completely dissolved to obtain solution A.
[0068] (P2) Dissolve 1g of polyacrylonitrile with a molecular weight of 150,000 in solution A in (P1) and stir magnetically at 60°C for 12h to obtain electrospinning ink.
[0069] (P3) The above ink was poured into a 10 mL syringe and a polyacrylonitrile nanofiber membrane loaded with manganese acetylacetone was prepared under the following conditions: temperature 30℃, average humidity 40%, positive pressure 14 kV, negative pressure -2.5 kV, receiving distance 15 cm, roller speed 100 r / min, and syringe translation speed 3 mm / s.
[0070] (P4) The nanofiber membrane in (P3) was dried in a vacuum oven at 60°C for 10 h.
[0071] (P5) The dried nanofiber membrane from (P4) was subjected to cyclization and oxidation treatment at 260°C for 2 hours in a muffle furnace.
[0072] (P6) The nanofiber membrane pre-oxidized in (P5) was heated to 840℃ in an argon atmosphere at a heating rate of 5℃ / min and held for 2h to obtain a self-supporting cathode catalyst (MOC@NCNF) for lithium-carbon dioxide batteries.
[0073] The physicochemical properties of MOC@NCNF were characterized: Figure 4 The figure shows a nanofiber membrane composed of manganese acetylacetone and polyacrylonitrile obtained by electrospinning. As can be seen from the figure, the nanofiber membrane can be easily prepared in large quantities. Figure 5 The image shows a scanning electrochemical electron microscope (SEM) image of MOC@NCNF. The image reveals that the diameter of the carbon nanofibers is less than 300 nm. This is due to the manganese-catalyzed graphitization of carbon during the carbonization process, resulting in nanofibers with smaller diameters than pure carbon fibers after loading with manganese oxide and manganese carbide. Figure 2 ). Figure 6 The transmission electron microscope image of MOC@NCNF shows that the fiber exhibits a distinct graphitized structure, forming a rapid electron transport channel. Figure 7 The X-ray diffraction pattern of MOC@NCNF shows that MOC@NCNF mainly contains two manganese compounds, MnO and Mn5C3.
[0074] Examples 2-6
[0075] In Examples 2-6, adaptive catalytic cathodes M2-M6 for lithium-carbon dioxide batteries were prepared. The steps were basically the same as steps P1-P6 of the adaptive catalytic cathode for lithium-carbon dioxide batteries in Example 1, except for the different types and amounts of raw materials and process parameters. See Table 1 for details.
[0076] Table 1. Summary of Raw Material Types, Usage, and Process Parameters
[0077]
[0078] Application examples
[0079] An application of an adaptive catalytic cathode for lithium-carbon dioxide batteries in batteries was described. A lithium-carbon dioxide battery cathode catalyst was prepared using the preparation method and process parameters in Example 1. NCNF in the comparative example was used as a control sample, and the battery electrochemical performance was tested.
[0080] The assembly and testing of the lithium-carbon dioxide battery were prepared according to the conventional battery assembly and testing process: A CR2032 positive electrode shell with vent holes, an MOC@NCNF or NCNF positive electrode sheet, and a GF-D separator were placed sequentially. Then, 80 μL of electrolyte (1M lithium bis(trifluoromethanesulfonyl)imide dissolved in tetraethylene glycol dimethyl ether) was added to the separator. Next, the lithium metal negative electrode, current collector, spring sheet, and CR2032 negative electrode shell were placed. After encapsulation, the battery was transferred to a self-made testing device, CO2 gas was introduced for 50 min, and then the battery was allowed to stand for 8 h before electrochemical performance testing was performed.
[0081] Electrochemical performance test results of lithium-carbon dioxide batteries: From Figure 8 The cyclic voltammetric curves of MOC@NCNF and NCNF cathodes show that MOC@NCNF exhibits larger reduction and oxidation currents compared to NCNF, indicating that the introduction of MOC significantly enhances the catalytic activity of NCNF in the discharge and charge processes of lithium-carbon dioxide batteries. Furthermore, MOC@NCNF shows improved catalytic activity at EC... c1 and E a1 The catalyst exhibits a reconstruction and pre-activation process. Figure 9 A comparison of full discharge and full charge performance shows that the discharge capacity of MOC@NCNF exceeds 10mAh cm⁻¹. -2 It is much higher than that of NCNF cathode, and the reversible efficiency of capacity reaches 64.94%. Figure 10 In the middle, the MOC@NCNF cathode is at 50 μA cm -2 Current density, 100 μAh cm -2 It can cycle stably for 327 cycles at the cutoff capacity without significant degradation. The cutoff capacity was further increased to 200 μAh cm⁻¹. -2 ( Figure 11 The battery can still cycle stably for nearly 1000 hours. Finally, in the rate performance test, MOC@NCNF also showed excellent rate performance, even at a current density of 100 μA / cm². -2 The battery can still cycle stably, and after the rate performance test, it can still operate stably when it returns to the initial current density.
[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.
Claims
1. A method for preparing an adaptive catalytic cathode for lithium-carbon dioxide batteries, characterized in that, Includes the following steps: 1) Add the manganese-based compound to N,N-dimethylformamide and stir until the manganese-based compound is completely dissolved to obtain solution A; 2) Add polyacrylonitrile to solution A and stir at the first preset temperature to obtain ink B; 3) Obtain a nanofiber membrane composed of polyacrylonitrile and manganese salt by electrospinning ink B; 4) Vacuum dry the nanofiber membrane to obtain a dried nanofiber membrane; 5) The dried nanofiber membrane is subjected to cyclization and oxidation treatment at a second preset temperature to obtain the treated nanofiber membrane; 6) The treated nanofiber membrane was carbonized in an inert atmosphere to obtain an adaptive catalytic cathode for lithium-carbon dioxide batteries.
2. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, The manganese-based compound is manganese nitrate hexahydrate, manganese acetate, manganese chloride tetrahydrate, or manganese acetylacetone.
3. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, The molecular weight of the polyacrylonitrile is 50,000, 85,000, 150,000 or 250,000.
4. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, The mass ratio of the manganese-based compound, N,N-dimethylformamide, and polyacrylonitrile is (0.2-0.9):(5-14):(0.6-1.4).
5. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, Magnetic stirring is used in both steps 1) and 2). The stirring time in step 1) is 30 min and the stirring time in step 2) is 12 h. The first preset temperature is 40-60℃.
6. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, The process parameters of the electrospinning method are as follows: temperature 30-60℃, average humidity 35-55%, positive high voltage 12-16KV, negative high voltage -2.5KV, receiving distance 10-20cm, roller speed 50-200r / min, and syringe translation speed 3mm / s.
7. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, In step 4), the vacuum drying temperature is 60-70℃ and the time is 10 hours. In step 5), the second preset temperature is 210-300℃, and the cyclization and oxidation treatment time is 1-6h.
8. The method for preparing an adaptive catalytic cathode for a lithium-carbon dioxide battery according to claim 1, characterized in that, In step 6), the inert atmosphere is nitrogen or argon, the heating rate is 2-5℃ / min, the carbonization temperature is 700-900℃, and the isothermal holding time is 2h.
9. An adaptive catalytic cathode for lithium-carbon dioxide batteries, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.
10. The application of the adaptive catalytic cathode of lithium-carbon dioxide battery as described in claim 9 in lithium-carbon dioxide batteries.