Graphene-surface-grafted free radical polymer composite material, and preparation method and use thereof

A graphene surface, composite material technology, applied in electrical components, electrochemical generators, circuits, etc., can solve the problems of limited performance improvement of secondary batteries, unsuitable for mass production, difficult to control graft content, etc. The preparation method is simple and easy, excellent dispersibility, and high repeatability.

Active Publication Date: 2019-06-14

SHANGHAI INST OF ORGANIC CHEMISTRY - CHINESE ACAD OF SCI

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is to overcome the difficulty in controlling the grafting content in the method for grafting the PTMA secondary battery cathode material on the surface of graphene sheet covalently bonded in t...

Method used

As can be seen from Fig. 7, with GO-g-PTMA as cathode material, the first charge-discharge specific capacity of secondary battery is 340mAh g-1, after 300 cycles specific capacity is 200mAh g-1 , has excellent charge-discharge cycle performance, and the first discharge specific capacity is also significantly improved compared with the 222mAh g-1 reported in the literature (Energy Environ. Sci. 2012, 5, 5221-5225.).

As can ...

Abstract

The invention discloses a graphene-surface-grafted free radical polymer composite material, and a preparation method and a use thereof. The preparation method comprises the following steps: 1) uniformly dispersing graphene in a solvent, uniformly mixing the obtained solution with 2,2,6,6-tetramethyl-4-piperidinyl methacrylate monomer, deoxidizing the obtained solution, uniformly mixing the solution with an initiator, carrying out a reaction for 1-72 h, and carrying out filtration and separation to obtain an intermediate, wherein a mass ratio of the graphene to the monomer to the initiator is 1:(11.25-90):(0.08-0.64), and the graphene is graphene oxide and/or reduced graphene oxide; and 2) uniformly mixing the intermediate, disodium edetate, sodium tungstate and hydrogen peroxide in a solvent, stirring and reacting the obtained mixture, and carrying out filtration and separation to obtain the composite material. The method is simplified, is suitable for mass production, and allows the grafting content of covalent bonds on surface of a graphene sheet to be easily controlled; and when the composite material is applied to cathodes of lithium ion batteries, the obtained secondary batteries have high performances.

Application Domain

Cell electrodesSecondary cells

Technology Topic

Cvd grapheneSolvent +13

Image

Examples

Experimental program(8)

Example Embodiment

[0068] Example 1: Synthesis of graphene oxide grafted poly(2,2,6,6-tetramethylpiperidine-4-methacrylate) (GO-g-PTMPM) composite material:

[0069] Add 100mg graphene oxide and 50mL N-methylpyrrolidone to a 100mL reaction flask, add 2.25g TMPM after ultrasonic dispersion, bubbling with nitrogen for 30min, add 32.8mg azobisisobutyronitrile, and react at 65℃ 48 hours. After the reaction, after suction filtration, washing and drying, GO-g-PTMPM with a graft content of 45.4% was obtained.

[0070] FT-IR(cm -1 ): 3400 (νO-H), 2960 (νC-H), 2930 (νC-H), 1725 (νC=O).

[0071] This example further proves that by controlling the time of the polymerization reaction, the graft content of the PTMPM grafted on the surface of the graphene oxide sheet can be adjusted.

[0072] Attached figure 2 In order to polymerize the thermal weight loss curve of the GO-g-PTMPM composite material obtained by polymerization at 65°C for 3-48 hours, it can be seen from the figure that as the polymerization reaction time increases, the more PTMPM is grafted on the surface of graphene oxide. It can be seen from the thermal weight loss curve that the mass fraction of GO-g-PTMPM composite material can be considered to no longer change at 700°C, that is, PTMPM has been completely decomposed. The graft content of the GO-g-PTMPM composite can be calculated from the mass fraction of the thermal weight loss at 700°C. The data are listed in Table 1.

[0073] Among them, the meaning of grafting content is the mass percentage of the mass of the grafted polymer to the total mass of the grafted composite material. The calculation method is w=(1-(w2/w1))*100%, where w1, w2 and w represent the remaining mass fraction of rGO or GO at 700℃, the remaining mass fraction of rGO-g-PTMPM or GO-g-PTMPM at 700℃, and PTMPM in rGO-g-PTMPM or GO-g-PTMPM The quality score.

[0074] The residual mass fractions of rGO and GO at 700℃ are 73.0% and 43.5%, respectively.

[0075] Table 1 The graft content of GO-g-PTMPM composites obtained by different polymerization reaction times

[0076] Response time (h)

Example Embodiment

[0077] Example 2: Synthesis of graphene oxide grafted poly(2,2,6,6-tetramethylpiperidine-4-methacrylate) (GO-g-PTMPM) composite material:

[0078] Add 100mg graphene oxide and 50mL N-methylpyrrolidone to a 100mL reaction flask, add 2.25g TMPM (molecular weight 225) after ultrasonic dispersion, bubbling with nitrogen for 30 minutes, add 16.4mg azobisisobutyronitrile ( The molecular weight is 164) and reacted at 65°C for 48 hours. After the reaction, after suction filtration, washing and drying, GO-g-PTMPM with a graft content of 30.2% was obtained.

[0079] This example further proves that by controlling the amount of the initiator, the graft content of the PTMPM grafted onto the surface of the graphene oxide sheet can be adjusted.

[0080] Table 2 The graft content of GO-g-PTMPM composites obtained with different initiator dosages

[0081] Molar ratio of monomer to initiator

[0082] Attached image 3 For the thermal weight loss curve of GO-g-PTMPM composite material obtained by polymerization of 200:1-200:4 at 65℃ for 48 hours, it can be seen from the figure that as the amount of initiator increases, the graphene oxide surface The more PTMPM of the branches. The graft content of the GO-g-PTMPM composite can be calculated from the mass fraction of the thermal weight loss at 700°C. The data are listed in Table 2.

Example Embodiment

[0083] Example 3: Synthesis of graphene oxide grafted poly(2,2,6,6-tetramethylpiperidine-1-oxyradical-4-methacrylate) (GO-g-PTMA):

[0084] Add 100 mg GO-g-PTMPM (specifically GO-g-PTMPM with a graft content of 45.4% in Example 1) and 100 mL methanol in a 250 mL reaction flask, and add 30 mg disodium edetate and 30 mg after ultrasonic dispersion. 20mg sodium tungstate dihydrate, then slowly add 4mL 30% hydrogen peroxide (density about 1.1). After stirring the reaction for 48 hours, the GO-g-PTMA was obtained by suction filtration, washing and drying.

[0085] FT-IR(cm -1 ): 3400 (νO-H), 2960 (νC-H), 2930 (νC-H), 1725 (νC=O), 1363 (νN-O).

[0086] Attached figure 1 The left picture shows the AFM and height distribution of GO, and the right picture shows the AFM and height distribution of GO-g-PTMA. It can be seen that the average thickness of GO lamella is 1.0nm, while the average thickness of GO-g-PTMA is 9nm.

[0087] Attached Image 6 For the electron paramagnetic resonance (ESR) curve of the free radical composite material prepared in Example 3, the characteristic signal of the nitroxide radical in GO-g-PTMA can be seen, and the calculated g value is 2.0019. The g value of the standard free radical is 2.0023, which further proves the existence of the TEMPO structure, and the N-H bond is successfully oxidized into nitroxide radicals; the comparison shows that the peak patterns are the same, indicating that the three radicals are of the same type and are all nitroxide radicals.

PUM

Property	Measurement	Unit
The average thickness	1.0	nm
The average thickness	9.0	nm

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

improve performance

Graphene-surface-grafted free radical polymer composite material, and preparation method and use thereof

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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