3D hierarchical structure hard carbon material and preparation method and application thereof

Abstract

The application discloses a 3D hierarchical structure hard carbon material and a preparation method and application thereof. The preparation method comprises the following steps: S1, adding divinylbenzene, styrene, a pore former and an initiator into a mixed solution containing an emulsifier, a stabilizer, polyvinyl alcohol and water to obtain a suspension; S2, heating and reacting the suspension obtained in the step S1 to obtain a styrene-divinylbenzene copolymer; and S3, pre-oxidizing and carbonizing the styrene-divinylbenzene copolymer obtained in the step S2 to obtain the 3D hierarchical structure hard carbon material. The 3D hierarchical polystyrene-based carbon flower-shaped microspheres with uniform sizes of 2-40 microns are prepared by a micro-suspension polymerization method, the particle size is increased while the material high exposure is maintained, and thus separation is facilitated. The problem that the particle size of the polystyrene-based carbon material with a 3D hierarchical structure synthesized by a hydrothermal method in the prior art is less than 1 micron and is not conducive to large-scale filtration is overcome.

Description

Technical Field

[0001] This application relates to a 3D hierarchical hard carbon material, its preparation method and application, belonging to the field of hard carbon material technology. Background Technology

[0002] Because 3D hierarchical carbon materials can prevent the stacking of low-dimensional modules, they can not only shorten the diffusion distance of matter or charge, but also greatly expose active sites to achieve high activity, durability and efficient catalysis, and have been widely studied in the fields of energy and catalysis. 3D hierarchical structures composed of low-dimensional building blocks such as 0D, 1D, and 2D structures can not only inherit the original properties of materials, but also bring unexpected superior performance. Currently, there are methods for preparing hierarchical flower-like, sea urchin-like and array carbon materials, commonly used methods include (i) hydrothermal method, (ii) template method, (iii) nanoemulsion assembly, (iv) space-confined assembly, (v) modular self-assembly and (vi) direct ink writing. The team led by Zhao Dongyuan has developed a method for synthesizing structured and functional mesoporous carbonaceous nanomaterials using single-molecule micelle self-assembly. This method yields various hierarchical mesoporous carbonaceous materials with particle sizes less than 200 nm. CN110252160A discloses a mixed-matrix gas separation membrane material containing 3D flower-like carbon materials and its preparation method. This method uses a solvothermal approach with polyimide as a raw material to synthesize 3D flower-like carbon materials with particle sizes around 700 nm. CN106432562B discloses a chloromethylated magnetic polystyrene nanosphere and its preparation method. Using iron oxide as a template, a styrene-chlorostyrene copolymer is coated onto the outer layer, and a multi-component superstructure is prepared using a template method, with particle sizes ranging from 20 to 140 nm. The 3D hierarchical carbon materials prepared by these methods typically have particles smaller than 1 μm, and the synthesis steps are complex, making large-scale production difficult. Summary of the Invention

[0003] According to one aspect of this application, a 3D hierarchical hard carbon material is provided, solving the following technical problem: A common method for large-scale preparation of 3D hierarchical polystyrene-based carbon materials is the hydrothermal method, but the particle size of the synthesized 3D hierarchical polystyrene-based carbon material synthesized by the hydrothermal method is less than 1 μm, which is not conducive to large-scale filtration. To overcome the above problem, this application employs a micro-suspension polymerization method to prepare 3D hierarchical polystyrene-based carbon flower-like microspheres with uniform size in the micrometer range, increasing the particle size while maintaining high material exposure, thereby facilitating separation.

[0004] The technical solution adopted in this application is as follows:

[0005] A method for preparing a 3D hierarchical hard carbon material includes the following steps:

[0006] S1. Add divinylbenzene, styrene, pore-forming agent, and initiator to a mixture containing emulsifier, stabilizer, polyvinyl alcohol, and water to obtain a suspension.

[0007] S2. The suspension obtained in step S1 is heated and reacted to obtain styrene-diethylenebenzene copolymer;

[0008] S3. The styrene-diethylenebenzene copolymer obtained in step S2 is pre-oxidized and carbonized to obtain the 3D hierarchical hard carbon material.

[0009] Microemulsion polymerization was used to control the particle size greater than 1 μm on the 3D scale, and emulsifiers and stabilizers were used as mixed emulsifiers to control the morphology on the low-dimensional scale, thereby obtaining a resin material with a 3D hierarchical structure at the micron particle size.

[0010] Optionally, in step S1, the molecular weight of the polyvinyl alcohol is 70,000 to 114,400.

[0011] Optionally, in step S1, the emulsifier is selected from at least one of OP-10, TX-10, NP-10, and Pingpingjia O-10.

[0012] Optionally, in step S1, the weight ratio of emulsifier to styrene is 0.2 to 0.4:1.

[0013] Optionally, in step S1, the stabilizer is selected from at least one of sodium dodecyl sulfonate and sodium alginate.

[0014] Optionally, in step S1, the weight ratio of the stabilizer to styrene is 0.1 to 0.2:1.

[0015] Optionally, in step S1, the weight ratio of polyvinyl alcohol to styrene is 0.05 to 0.1:1.

[0016] Optionally, in step S1, the weight ratio of water to styrene is 3 to 15:1.

[0017] Optionally, in step S1, the pore-forming agent is selected from C6 to C6. 15 The pore-forming agent is selected from at least one of liquid alkanes, wherein the pore-forming agent has a boiling point greater than 120°C.

[0018] Optionally, in step S1, the weight ratio of the pore-forming agent to styrene is 1.5 to 2.5:1.

[0019] Optionally, the pore-forming agent is selected from at least one of dodecane, tridecane, and tetradecane.

[0020] Optionally, in step S1, the initiator is selected from at least one of benzoyl peroxide, azobisisobutyronitrile, and lauryl peroxide.

[0021] Optionally, in step S1, the mass ratio of the initiator to styrene is 0.01 to 0.01:1.

[0022] Optionally, in step S1, the weight ratio of divinylbenzene to styrene is 0.6 to 2:1.

[0023] Optionally, in step S2, the heating reaction includes stage I, stage II, and stage III.

[0024] The reaction conditions for stage I are: a reaction temperature of 65–72°C and a reaction time of 1–4 hours.

[0025] The reaction conditions for stage II are: a reaction temperature of 72–78°C and a reaction time of 3–12 hours.

[0026] The reaction conditions for stage III are: a reaction temperature of 82–95°C and a reaction time of 8–16 h.

[0027] Optionally, a stage II-1 is further included between stage II and stage III, wherein the reaction conditions for stage II-1 are: a reaction temperature of 78 to 82°C and a reaction time of 0.2 to 0.8 h.

[0028] Optionally, in step S3, the pre-oxidation conditions include:

[0029] The process is carried out under an oxidizing atmosphere, with a pre-oxidation temperature of 60–300℃ and a pre-oxidation time of 6–10 h.

[0030] The oxidizing atmosphere is oxygen or air;

[0031] Optionally, the heating rate for pre-oxidation is 3–10 °C / min.

[0032] Optionally, the carbonization conditions include:

[0033] The carbonization is carried out in an inert gas atmosphere, with a carbonization temperature of 700–1600℃ and a carbonization time of 0.5–10 h; the heating rate is 1–15℃ / min.

[0034] Optionally, the inactive gas atmosphere is selected from at least one of nitrogen, helium, and argon.

[0035] According to another aspect of this application, a 3D hierarchical hard carbon material is provided, characterized in that the 3D hierarchical hard carbon material is prepared by the above-described preparation method.

[0036] Optionally, the 3D hierarchical hard carbon material is a flower-shaped microsphere with a three-dimensional multi-level structure.

[0037] Optionally, the average particle size of the 3D hierarchical hard carbon material is 2–40 μm.

[0038] According to another aspect of this application, the above-mentioned 3D hierarchical hard carbon material is also provided for use in lithium-ion batteries, sodium-ion batteries, and oxygen reduction electrocatalysts.

[0039] The beneficial effects that this application can produce include:

[0040] The method for preparing 3D hierarchical hard carbon materials provided in this application is a synthesis method for 3D hierarchical polystyrene-based carbon flower-like microspheres. 3D hierarchical polystyrene-based carbon flower-like microspheres with a size of 2–40 μm are prepared by micro-suspension polymerization. This method increases the particle size while maintaining high material exposure, thus facilitating separation. The average particle size before carbonization is 4–60 μm, and the average particle size after carbonization is 2–40 μm, with a specific surface area of ​​less than 70 m². 2 / g, overcoming the problem that the particle size of polystyrene-based carbon materials synthesized by the hydrothermal method in the prior art is less than 1μm, which is not conducive to large-scale filtration. Attached Figure Description

[0041] Figure 1 The image shown is a scanning electron microscope image of the sample in Example 1, at a scale of 10 μm.

[0042] Figure 2 Scanning electron microscope images of the sample in Comparative Example 2, at a scale of 10 μm. Detailed Implementation

[0043] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials used in the embodiments of this application were purchased commercially.

[0045] The commercial brand name of the polyvinyl alcohol used in the examples is PVA 2488.

[0046] Example 1

[0047] Step 1: Add 1g of OP-10 and 1g of sodium dodecyl sulfonate to 70g of 1% polyvinyl alcohol aqueous solution, stir until dissolved, then add a mixed solution of 6g diethylenebenzene, 7g styrene, 10g tridecane and 0.18g benzoyl peroxide (with the polymerization inhibitor removed), heat to 70℃ and react for 2h, then heat to 75℃ and react for 4h, then heat to 80℃ and react for 0.5h, and finally heat to 90℃ and react for 11h.

[0048] Step 2: After washing and drying, the obtained styrene-diethylenebenzene copolymer is pre-oxidized by heating to 280℃ at a rate of 6℃ / min and maintaining the temperature in air for 2 hours. The innovative aspect of this step is the slow heating to 280℃ for oxidative crosslinking and evaporation of the pore-forming agent.

[0049] Step 3: The pre-oxidized sample was heated to 1400℃ under a nitrogen atmosphere at a heating rate of 5℃ / min and maintained for 2 hours to obtain the sample. In Example 1, the average particle size of the sample before carbonization was 40μm, and the average particle size after carbonization was 24μm, with a specific surface area of ​​24m². 2 / g. SEM morphology images are attached. Figure 1 As shown, the particle size distribution is uniform, and the structure is hierarchical and flower-like.

[0050] Example 2

[0051] 2.8 g of OP-10 and 1.4 g of sodium dodecyl sulfonate were added to 105 g of 0.05% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 14 g diethylenebenzene, 7 g styrene, 17.5 g tetradecane, and 0.7 g azobisisobutyronitrile (AIBN) with the polymerization inhibitor removed was added. The mixture was heated to 70 °C for 2 h, then to 75 °C for 4 h, then to 82 °C for 0.2 h, and finally to 90 °C for 11 h. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 300 °C at a rate of 3 °C / min and maintaining the temperature in air for 10 h. The pre-oxidized sample was then heated to 1400 °C at a rate of 5 °C / min and maintained for 2 h under a nitrogen atmosphere to obtain the final sample. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0052] Example 3

[0053] 1.4 g of 1.4 g of 1.67% polyvinyl alcohol (PVA) and 0.7 g of sodium dodecyl sulfonate were added to an aqueous solution of 21 g of 1.67% PVA. After stirring until dissolved, a mixed solution of 4.2 g of diethylenebenzene, 7 g of styrene, 10.5 g of tridecane, and 0.07 g of lauryl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 70 °C for 2 h, then to 75 °C for 4 h, then to 80 °C for 0.5 h, and finally to 90 °C for 11 h. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 250 °C at a rate of 3 °C / min and maintaining the temperature in air for 10 h. The pre-oxidized sample was then heated to 1400 °C at a rate of 5 °C / min and maintained for 2 h under a nitrogen atmosphere to obtain the final sample. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0054] Example 4

[0055] 0.7g of OP-10, 0.7g of TX-10, and 1g of sodium alginate were added to 60g of a 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 10g diethylenebenzene, 7g of styrene, 10g of tridecane, and 0.11g of azobisisobutyronitrile (AIBN) with the polymerization inhibitor removed was added. The mixture was heated to 70°C and reacted for 2 hours, then to 75°C and reacted for 4 hours, then to 80°C and reacted for 0.5 hours, and finally to 90°C and reacted for 11 hours. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 250°C at a rate of 3°C / min and maintaining the temperature in air for 10 hours. The pre-oxidized sample was then heated to 1400°C at a rate of 5°C / min and maintained for 2 hours under a nitrogen atmosphere to obtain the final sample. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0056] Example 5

[0057] 1g of OP-10, 0.7g of NP-10, and 1g of sodium alginate were added to 70g of a 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g of n-hexane, and 0.11g of benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 72°C and reacted for 1 hour, then to 78°C and reacted for 3 hours, and finally to 95°C and reacted for 8 hours. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 60°C at a rate of 1°C / min and maintaining the temperature in air for 10 hours. The pre-oxidized sample was then heated to 700°C at a rate of 1°C / min and maintained for 10 hours under a nitrogen atmosphere to obtain the final sample. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0058] Example 6

[0059] 1g of OP-10 and 1g of sodium dodecyl sulfonate were added to 70g of 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g tridecane, and 0.18g benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 65°C and reacted for 4 hours, then to 72°C and reacted for 12 hours, then to 78°C and reacted for 0.8 hours, and finally to 82°C and reacted for 16 hours. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized under oxygen conditions by heating to 300°C at a rate of 10°C / min and maintaining the temperature for 10 hours. The pre-oxidized sample was then heated to 1400°C under nitrogen atmosphere at a rate of 10°C / min and maintained for 2 hours. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0060] Example 7

[0061] 1g of OP-10 and 1g of sodium dodecyl sulfonate were added to 70g of 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g tridecane, and 0.18g benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 65°C and reacted for 4 hours, then to 72°C and reacted for 12 hours, then to 78°C and reacted for 0.8 hours, and finally to 82°C and reacted for 16 hours. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized under oxygen conditions by heating to 300°C at a rate of 10°C / min and maintaining the temperature for 10 hours. The pre-oxidized sample was then heated to 1600°C under nitrogen atmosphere at a rate of 15°C / min and maintained for 2 hours. The structural morphology was similar to that of the sample in Example 1, with uniform particle size distribution and a hierarchical flower-like structure, differing only in average particle size.

[0062] Comparative Example 1

[0063] 1g of OP-10 was added to 70g of 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g tridecane, and 0.18g benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 70℃ and reacted for 2h, then to 75℃ and reacted for 4h, then to 80℃ and reacted for 0.5h, and finally to 90℃ and reacted for 11h. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating it to 250℃ at 3℃ / min and maintaining it for 10h in air. The pre-oxidized sample was then heated to 1400℃ at a heating rate of 5℃ / min and maintained for 2h under a nitrogen atmosphere to obtain a sample without a specific morphology. This comparative example shows that the absence of a stabilizer leads to the absence of secondary structures, resulting in the dispersed phases combining to form a non-uniform material during suspension polymerization.

[0064] Comparative Example 2

[0065] 1g of sodium dodecyl sulfonate was added to 70g of 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g tridecane, and 0.18g benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 70℃ and reacted for 2h, then to 75℃ and reacted for 4h, then to 80℃ and reacted for 0.5h, and finally to 90℃ and reacted for 11h. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 250℃ at a rate of 3℃ / min and maintaining the temperature in air for 10h. The pre-oxidized sample was then heated to 1400℃ at a rate of 5℃ / min and maintained for 2h under a nitrogen atmosphere to obtain the final sample. SEM images are attached. Figure 2 As shown, without the addition of nonionic emulsifiers, the resulting morphology has only a low-dimensional structure and does not produce a uniformly distributed particle size.

[0066] Comparative Example 3

[0067] 1g of OP-10 and 1g of sodium dodecyl sulfonate were added to 70g of 1% polyvinyl alcohol aqueous solution and stirred until dissolved. Then, a mixed solution of 6g diethylenebenzene, 7g styrene, 10g solid paraffin, and 0.18g benzoyl peroxide (with the polymerization inhibitor removed) was added. The mixture was heated to 80°C and reacted for 4 hours, then heated to 95°C and reacted for 12 hours. After washing and drying, the resulting styrene-diethylenebenzene copolymer was pre-oxidized by heating to 250°C at 3°C / min and maintaining the temperature in air for 10 hours. The pre-oxidized sample was then heated to 1400°C at a heating rate of 5°C / min and maintained for 2 hours under a nitrogen atmosphere, resulting in a sample without a specific morphology. This indicates that the reaction conditions and the type of pore-forming agent in the polymerization process have a significant impact on the morphology of the polymer.

[0068] Test Example 1

[0069] The samples obtained in Examples 1, 2, 3, 4, 5, 6, and 7, and Comparative Examples 1, 2, and 3 were tested and analyzed. The results are shown in Table 1.

[0070] In battery testing, ethyl carbonate and vinyl fluoride (1:1) in 1M NaClO4 solution were used as the electrolyte. The working electrode consisted of active material, Ketjen black, and sodium carboxymethyl cellulose in a mass ratio of 7:2:1. The mass load of the active material in the electrode was approximately 1 mg cm⁻². Constant current charge-discharge tests were performed in the range of 0.01–3 V.

[0071] Table 1

[0072] <![CDATA[Specific surface area (m 2 / g)]]> Average particle size after carbonization (µm) <![CDATA[Specific capacity (mAh g -1 )]]> First-efficacy (%) Example 1 24 24 331.18 94.7 Example 2 15 30 324.48 93.5 Example 3 8 8 334.75 94.5 Example 4 35 21 324.17 92.4 Example 5 46 40 313.14 91.2 Example 6 24 15 335.24 91.3 Example 7 7 2 315.71 95.2 Comparative Example 1 12 65 310.12 88.7 Comparative Example 2 21 20 305.45 84.5 Comparative Example 3 7 12 312.11 84.8

[0073] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a 3D hierarchical hard carbon material, characterized in that, Includes the following steps: S1. Add divinylbenzene, styrene, pore-forming agent, and initiator to a mixture containing emulsifier, stabilizer, polyvinyl alcohol, and water to obtain a suspension. S2. The suspension obtained in step S1 is heated and reacted to obtain styrene-diethylenebenzene copolymer; S3. The styrene-diethylenebenzene copolymer obtained in step S2 is pre-oxidized and carbonized to obtain the 3D hierarchical hard carbon material. In step S1, the pore-forming agent is selected from C6~C6. 15 The pore-forming agent is selected from at least one of liquid alkanes, wherein the pore-forming agent has a boiling point greater than 120°C; In step S2, the heating reaction includes stage I, stage II, and stage III; The reaction conditions for stage I are: a reaction temperature of 65~72℃ and a reaction time of 1h~4h. The reaction conditions for stage II are: a reaction temperature of 72~78℃ and a reaction time of 3h~12h; The reaction conditions for stage III are: a reaction temperature of 82~95℃ and a reaction time of 8~16h.

2. The preparation method according to claim 1, characterized in that, In step S1, the molecular weight of the polyvinyl alcohol is 70,000 to 114,400.

3. The preparation method according to claim 1, characterized in that, In step S1, the emulsifier is selected from at least one of OP-10, TX-10, NP-10, and Pingpingjia O-10.

4. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of emulsifier to styrene is 0.2~0.4:

1.

5. The preparation method according to claim 1, characterized in that, The stabilizer is selected from at least one of sodium dodecyl sulfonate and sodium alginate.

6. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of the stabilizer to styrene is 0.1~0.2:

1.

7. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of polyvinyl alcohol to styrene is 0.05~0.1:

1.

8. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of water to styrene is 3~15:

1.

9. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of the pore-forming agent to styrene is 1.5~2.5:

1.

10. The preparation method according to claim 1, characterized in that, In step S1, the initiator is selected from at least one of benzoyl peroxide, azobisisobutyronitrile, and lauryl peroxide.

11. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the initiator to styrene is 0.01~0.01:

1.

12. The preparation method according to claim 1, characterized in that, In step S1, the weight ratio of divinylbenzene to styrene is 0.6 to 2:

1.

13. The preparation method according to claim 1, characterized in that, Between stage II and stage III, there is also a stage II-1, the reaction conditions of which are: reaction temperature of 78~82℃ and reaction time of 0.2h~0.8h.

14. The preparation method according to claim 1, characterized in that, In step S3, the pre-oxidation conditions include: The process is carried out under an oxidizing atmosphere, with a pre-oxidation temperature of 60~300℃ and a pre-oxidation time of 6~10h; The oxidizing atmosphere is oxygen or air.

15. The preparation method according to claim 14, characterized in that, The heating rate for pre-oxidation is 3~10℃ / min.

16. The preparation method according to claim 1, characterized in that, The carbonization conditions include: The carbonization is carried out in an inert gas atmosphere, with a carbonization temperature of 700~1600℃ and a carbonization time of 0.5~10h; the heating rate is 1~15℃ / min.

17. A 3D hierarchical hard carbon material, characterized in that, The 3D hierarchical hard carbon material is prepared by the preparation method described in any one of claims 1 to 16.

18. The 3D hierarchical hard carbon material according to claim 17, characterized in that, The 3D hierarchical hard carbon material is a flower-shaped microsphere with a three-dimensional multi-level structure.

19. The 3D hierarchical hard carbon material according to claim 17, characterized in that, The average particle size of the 3D hierarchical hard carbon material is 2~40μm.

20. The application of the 3D hierarchical hard carbon material according to any one of claims 17 to 19 in lithium-ion batteries, sodium-ion batteries, and oxygen reduction electrocatalysts.

Images