A phenolic resin reduced graphene oxide composite material, a preparation method and applications thereof

Abstract

This invention discloses a phenolic resin-reduced graphene oxide composite material, its preparation method, and its application. The preparation method of this composite material is as follows: 1) Mix deionized water, concentrated hydrochloric acid, and paraformaldehyde, and react in a water bath at 45-60℃ for 1-3 hours; 2) Add phenolic resin at a concentration of 1.5-5 mg / mL. ‑1 The process involves: 1) adding hydroquinone to a graphene oxide aqueous solution; 2) adding hydroquinone under inert gas protection and reacting at 60°C for 24 hours; 3) adding a reducing agent and reacting in an oil bath at 90-100°C for 1-2 hours. The resulting solid-liquid mixture is then washed and filtered to obtain a phenolic resin-reduced graphene oxide composite material. During the preparation process, phenolic resin is polymerized in situ onto the surface of reduced graphene oxide, giving the material outstanding rate performance. The strong adsorption between the phenolic resin and graphene ensures excellent cycle stability. The disordered structure of the phenolic resin itself allows the electrode material to function effectively even in harsh environments with low temperatures (0°C) and electrode pulverization.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery electrode material technology, specifically relating to a phenolic resin reduced graphene oxide composite material, its preparation method, and its application. Background Technology

[0002] Currently, the cathode material for commercially available lithium-ion batteries is primarily lithium iron phosphate (LFP). LFP electrode materials offer advantages such as low cost, long cycle life, excellent safety performance, and stable voltage platform; however, their theoretical specific capacity is very low (170 mAh·g). -1 Its poor rate performance and failure under harsh conditions such as low temperature and electrode pulverization limit its application. Organic electrode materials, composed of inexpensive and sustainable elements such as carbon, hydrogen, and oxygen, can achieve a very high theoretical specific capacity (446 mAh·g) through rational molecular design. -1 Quinones, with their advantages of rapid redox flow, abundant sources, and environmental friendliness, are considered the most promising candidates for next-generation lithium-ion battery cathode materials.

[0003] However, quinone molecules are highly soluble in organic electrolytes, leading to poor cycle stability of the battery. To effectively leverage the energy storage advantages of quinone molecules, they are often combined with ordered mesoporous carbon materials, single-walled carbon nanotubes, etc., or their molecular weight is increased through polymerization to improve solubility. Although the cycle stability of the materials is improved, these quinone substances introduce a large number of non-electroactive groups into the structural design, resulting in a decrease in the theoretical specific capacity of the material, and the material itself has very low conductivity (<10). -5 S·cm -1 The high cost of ordered mesoporous carbon materials and single-walled carbon nanotubes, the environmental pollution caused by organic solvents introduced during the synthesis of quinone active substances, and the complexity of the synthesis methods all limit their commercial application. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a phenolic resin reduced graphene oxide composite material, its preparation method and application, which solves the problems of cathode material performance, cost and applicability in the above-mentioned background art.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for preparing a phenolic resin-reduced graphene oxide composite material, comprising the following steps:

[0006] 1) Mix deionized water, concentrated hydrochloric acid, and trioxymethylene, and react in a water bath at 45-60℃ for 1-3 hours;

[0007] 2) Add a concentration of 1.5-5 mg / mL-1 An aqueous solution of graphene oxide;

[0008] 3) Under inert gas protection, add hydroquinone and react at 55-70℃ for 20-30 hours;

[0009] 4) Add reducing agent, react in oil bath at 90-100℃ for 1-2 hours, wash and filter the solid-liquid mixture generated by the reaction to obtain phenolic resin reduced graphene oxide composite material.

[0010] The molar ratio of trioxymethylene to hydroquinone is 1:1.5 to 1:3.

[0011] In this invention, the molar ratio of trioxymethylene to hydroquinone is 1:3.

[0012] In this invention, in step 2), after adding the graphene oxide solution, the mixture is magnetically stirred for 1-3 hours.

[0013] In this invention, in step 3), the inert gas is nitrogen or argon.

[0014] In this invention, in step 4), the reducing agent is hydrazine hydrate, sodium ascorbate, or phosphorous acid.

[0015] The present invention also provides a phenolic resin-reduced graphene oxide composite material prepared by the above method. In this composite material, phenolic resin is polymerized in situ on the surface of the reduced graphene oxide sheets.

[0016] In this invention, the mass ratio of phenolic resin to reduced graphene oxide is 1:10 to 10:1.

[0017] The present invention also provides the application of the above-mentioned phenolic resin reduced graphene oxide composite material as a cathode material for lithium-ion batteries, which is suitable for harsh environments with low temperature (0°C) and electrode pulverization.

[0018] Compared with the prior art, this technical solution has the following advantages:

[0019] 1. The preparation method of this invention is simple, and the target product can be obtained by "one-pot method"; no organic solvents are required in the preparation process, which is green and safe and reduces environmental pollution; the preparation cost is low, the reaction conditions are easy to control, the product composition is controllable, which is conducive to large-scale production;

[0020] 2. The composite material prepared by this invention has a very high theoretical specific capacity of phenolic resin (446 mAh·g). -1The composite film possesses extremely high energy density. The in-situ polymerization of phenolic resin on the surface of reduced graphene oxide sheets gives the material outstanding rate performance. The strong adsorption between phenolic resin and reduced graphene oxide ensures the material's excellent cycle stability. The disordered structure of phenolic resin itself allows the electrode material to function even in harsh environments such as low temperature (0°C) and electrode pulverization, which is a range of applications that lithium iron phosphate electrode materials do not have.

[0021] 3. The composite material prepared by this invention has a wide range of applications, outstanding performance, and low cost, and can be used as a commercial lithium-ion battery cathode material. Attached Figure Description

[0022] Figure 1 A photograph of the composite material prepared in Example 1;

[0023] Figure 2 (a) and (b) show the microstructure of the composite material prepared in Example 1 at different magnifications;

[0024] Figure 3 The results of the rate performance test of the composite material prepared in Example 1;

[0025] Figure 4 The results of the cyclic testing of the composite material prepared in Example 1;

[0026] Figure 5 The graph shows a comparison of the rate performance of the composite material prepared in Example 1 with other materials, including quinone materials with the same molecular structure (a), graphene composite quinone materials (b), carbon nanotube and ordered mesoporous carbon composite quinone materials (c), and other quinone materials (d).

[0027] Figure 6 The figure shows a comparison of the composite material prepared in Example 1 with other materials in terms of long-cycle stability. Among them, quinone materials with the same molecular structure (a), graphene composite quinone materials (b), carbon nanotube and ordered mesoporous carbon composite quinone materials (c), and other quinone materials (d).

[0028] Figure 7 The results of the destructive testing of the composite material prepared in Example 1;

[0029] Figure 8 The results of low-temperature testing of the composite material prepared in Example 1;

[0030] Figure 9 The results are as follows: The composite material prepared in Example 1 was tested in different electrolytes;

[0031] Figure 10This is a cost comparison chart of the composite material prepared in Example 1 and the lithium iron phosphate electrode material.

[0032] Figure 11 Cyclic performance of phenolic resin / reduced graphene oxide composite membranes obtained with different amounts of reduced graphene oxide.

[0033] Table 1 shows... Figure 11 The dosage of hydroquinone, paraformaldehyde, and reduced graphene oxide used in the process

[0034]

[0035] Figure 12 It is a phenol-trioxymethylene-reduced graphene oxide composite system.

[0036] Figure 13 It is a hydroquinone-formaldehyde-reduced graphene oxide composite system. Detailed Implementation

[0037] Example 1

[0038] This embodiment describes a method for preparing a phenolic resin-reduced graphene oxide composite material, comprising the following steps:

[0039] Add 5 mL of deionized water, 2 mL of concentrated hydrochloric acid (37%), and 30 mg of paraformaldehyde sequentially to a three-necked flask, and react in a water bath at 50 °C for 1.5 h. Take a sample containing 10 mg / g of paraformaldehyde. -1 6.6 g of graphene oxide solution was diluted with 10 mL of deionized water and magnetically stirred for 1.5 h. The diluted graphene oxide aqueous solution and 8 mL of deionized water were added sequentially. Under argon protection, 110 mg of hydroquinone was added, and the reaction was carried out at 60 °C for 24 h. 100 μL of 80% hydrazine hydrate was added, and the reaction was carried out in an oil bath at 90 °C for 1.5 h, yielding a black precipitate. The solid-liquid mixture was added to a large amount of deionized water and filtered to obtain a phenolic resin-reduced graphene oxide composite membrane (material), denoted as FQ / rGO.

[0040] In this embodiment, the molar ratio of paraformaldehyde to hydroquinone is 1:3. The prepared phenolic resin reduced graphene oxide composite film is shown in the figure. Figure 1 .

[0041] Figure 2 (a) and (b) show the microstructure of the phenolic resin / reduced graphene oxide composite film. No obvious polymer particles were observed under scanning electron microscopy or transmission electron microscopy. The phenolic resin sheets were adsorbed on the surface of the graphene sheets at the angstrom scale.

[0042] like Figure 3 Due to the very high theoretical specific capacity of phenolic resin (446 mAh g),-1 This endows the composite membrane with extremely high energy density; the material achieves an energy density of 500 mA·g. -1 At current density, the discharge specific energy reaches as high as 330 Wh·kg. -1 Graphene substrates, acting as conductors for electron transport, can significantly improve the conductivity of electrode materials, thereby enhancing their rate performance. The material at 10000 mA·g... -1 At high current densities, a capacity of up to 225 mAh·g was achieved. -1 Reversible capacity.

[0043] like Figure 4 The tight bonding between the phenolic resin and the graphene substrate inhibited the dissolution of the phenolic resin in the electrolyte, significantly improving the cycle stability of the electrode material at 2500 mA·g. -1 After 1000 cycles at a current density, the capacity retention rate is as high as 99.2%.

[0044] Figure 5 , 6 This embodiment compares the phenolic resin-reduced graphene oxide composite film with quinone materials of the same molecular structure, graphene-quinone composite materials, carbon nanotube-ordered mesoporous carbon composite quinone materials, and other quinone materials. Regarding rate performance, this embodiment exhibits advantages in actual specific capacity at high current densities, such as... Figure 5 In terms of cycle stability, this embodiment achieves a high level, such as... Figure 6 In particular, among quinone materials with the same molecular structure, this embodiment exhibits the best overall performance (rate performance and cycle stability).

[0045] like Figure 7 After the electrode material was artificially damaged, there was no capacity decay. After dozens of activation cycles, the capacity was comparable to that before the damage.

[0046] like Figure 8 In the low-temperature test, after dozens of activation cycles, the average actual specific capacity at 0℃ reached 75% of that at room temperature (26℃) in the subsequent 1000 cycles, showing excellent low-temperature activity.

[0047] like Figure 9 The electrode material exhibits similar performance in different electrolytes, indicating that it is universally applicable to different electrolytes.

[0048] Furthermore, addressing the issue of poor cycle stability in organic cathode materials, directly combining the active material with graphene may result in low energy density and poor rate performance of the active material. Additionally, its preparation is costly, the synthesis route is complex, and the use of organic solvents causes environmental pollution, limiting its large-scale industrial production. The composite material prepared using this method, as a battery cathode material, exhibits extremely high energy density, outstanding rate performance, and excellent cycle stability, making it suitable for harsh operating environments. It also boasts low cost (e.g., ...). Figure 10 The cost of preparing 1 kg of phenolic resin / reduced graphene oxide composite film is only $225. The synthesis route is simple and does not require the use of any organic solvents, which gives it broad commercial prospects.

[0049] like Figure 12 The paper shows the rate performance of the phenol-trioxymethylene-reduced graphene oxide composite film obtained by the phenol-trioxymethylene-reduced graphene oxide composite system, compared to... Figure 3 In Example 1, the performance of the hydroquinone-trioxymethylene composite membrane significantly decreased. Figure 13 The hydroquinone-formaldehyde-reduced graphene oxide composite system showed that it could not form a film smoothly.

[0050] Example 2

[0051] The difference between this embodiment and Embodiment 1 is that:

[0052] Add 5 mL of deionized water, 2 mL of concentrated hydrochloric acid (37%), and 40 mg of trioxymethylene sequentially to a three-necked flask, and react in a water bath at 50°C for 1.5 h. Take a sample containing 10 mg g of trioxymethylene. -1 6.6 g of graphene oxide solution was diluted with 10 mL of deionized water and magnetically stirred for 1.5 h. The diluted graphene oxide aqueous solution and 8 mL of deionized water were added sequentially. Under argon protection, 110 mg of hydroquinone was added, and the reaction was carried out at 60 °C for 24 h. 100 μL of 80% hydrazine hydrate was added, and the reaction was carried out in an oil bath at 90 °C for 1.5 h, yielding a black precipitate. The solid-liquid mixture was added to a large amount of deionized water and filtered to obtain a phenolic resin / reduced graphene oxide composite membrane.

[0053] Example 3

[0054] The difference between this embodiment and Embodiment 1 is that:

[0055] Add 5 mL of deionized water, 2 mL of concentrated hydrochloric acid (37%), and 50 mg of trioxymethylene sequentially to a three-necked flask, and react in a water bath at 50°C for 1.5 h. Take a sample containing 10 mg g of trioxymethylene. -16.6 g of graphene oxide solution was diluted with 10 mL of deionized water and magnetically stirred for 1.5 h. The diluted graphene oxide aqueous solution was then added, followed by 8 mL of deionized water. Under argon protection, 110 mg of hydroquinone was added, and the reaction was carried out at 60 °C for 24 h. 100 μL of 80% hydrazine hydrate was added, and the reaction was carried out in an oil bath at 90 °C for 1.5 h, yielding a black precipitate. The solid-liquid mixture was added to a large amount of deionized water and filtered to obtain a phenolic resin / graphene composite membrane.

[0056] Example 4

[0057] The difference between this embodiment and Embodiment 1 is that:

[0058] 5 mL of deionized water, 2 mL of concentrated hydrochloric acid (37%), and 60 mg of paraformaldehyde were added sequentially to a three-necked flask, and the mixture was reacted in a water bath at 50 °C for 1.5 h. 6.6 g of a graphene oxide solution containing 10 mg g⁻¹ was taken and diluted with 10 mL of deionized water, and the mixture was magnetically stirred for 1.5 h. The diluted graphene oxide aqueous solution and 8 mL of deionized water were added sequentially. Under argon protection, 220 mg of hydroquinone was added, and the mixture was reacted at 60 °C for 24 h. 100 μL of hydrazine hydrate (80%) was added, and the mixture was reacted in an oil bath at 90 °C for 1.5 h, yielding a black precipitate. The solid-liquid mixture was added to a large amount of deionized water and filtered to obtain a phenolic resin / reduced graphene oxide composite membrane.

[0059] Example 5

[0060] The difference between this embodiment and Embodiment 1 is that:

[0061] 5 mL of deionized water, 2 mL of concentrated hydrochloric acid (37%), and 15 mg of paraformaldehyde were added sequentially to a three-necked flask, and the mixture was reacted in a water bath at 50 °C for 1.5 h. 6.6 g of a graphene oxide solution containing 10 mg g⁻¹ was taken and diluted with 10 mL of deionized water, and the mixture was magnetically stirred for 1.5 h. The diluted graphene oxide aqueous solution and 8 mL of deionized water were added sequentially. Under argon protection, 55 mg of hydroquinone was added, and the mixture was reacted at 60 °C for 24 h. 100 μL of hydrazine hydrate (80%) was added, and the mixture was reacted in an oil bath at 90 °C for 1.5 h, yielding a black precipitate. The solid-liquid mixture was added to a large amount of deionized water and filtered to obtain a phenolic resin / reduced graphene oxide composite membrane, wherein the mass ratio of polymer to graphene oxide was 1:1.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a phenol formaldehyde resin reduced graphene oxide composite material, characterized by: Includes the following steps: 1) Mix deionized water, concentrated hydrochloric acid, and trioxymethylene, and react in a water bath at 45-60℃ for 1-3 hours; 2) adding an aqueous solution of graphene oxide at a concentration of 1.5-5 mg mL -1 ; 3) Under inert gas protection, add hydroquinone and react at 55-70℃ for 20-30 hours; 4) Add reducing agent, react in oil bath at 90-100℃ for 1-2 hours, wash and filter the solid-liquid mixture generated by the reaction to obtain phenolic resin reduced graphene oxide composite material. The molar ratio of trioxymethylene to hydroquinone is 1:1.5 to 1:

3.

2. The method for preparing a phenolic resin-reduced graphene oxide composite material according to claim 1, characterized in that: The molar ratio of trioxymethylene to hydroquinone is 1:

3.

3. The method for preparing a phenolic resin-reduced graphene oxide composite material according to claim 1, characterized in that: In step 2), after adding the graphene oxide solution, stir magnetically for 1-3 hours.

4. The method for preparing a phenolic resin-reduced graphene oxide composite material according to claim 1, characterized in that: In step 3), the inert gas is nitrogen or argon.

5. The method for preparing a phenolic resin-reduced graphene oxide composite material according to claim 1, characterized in that: In step 4), the reducing agent is hydrazine hydrate, sodium ascorbate, or phosphorous acid.

6. A phenol formaldehyde resin reduced graphene oxide composite material, characterized by: It is prepared by the method described in any one of claims 1-5.

7. The phenolic resin-reduced graphene oxide composite according to claim 6, characterized in that: Phenolic resin is polymerized in situ on the surface of reduced graphene oxide sheets.

8. The phenolic resin-reduced graphene oxide composite material according to claim 6, characterized in that: The mass ratio of phenolic resin to reduced graphene oxide is 1:10 to 10:

1.

9. The application of the phenolic resin-reduced graphene oxide composite material according to any one of claims 6-8, characterized in that: As a cathode material for lithium-ion batteries.

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