COMPRESSIVE GRAPHENE HYDROGEL AND PREPARATION METHOD THEREFOR

Abstract

This present invention disclosed a compressive graphene hydrogel and relates to a preparation method thereof. The compressive graphene hydrogel is obtained using the oxidized graphene and phytic acid as raw materials, wherein the oxidized graphene is used as the precursor. The obtained graphene hydrogel has a rich micro gap structure, a super large surface area, and high conductivity.

Claims

1. A compressive graphene hydrogel, wherein the compressive graphene hydrogel is prepared by using oxidized graphene and phytic acid as raw materials.

2. A process of preparing a compressive graphene hydrogel by using a hydrothermal method, the process comprising: using oxidized graphene as precursor; adding water into said oxidized graphene to make an aqueous solution; placing said aqueous solution in a reactor lining; doping said aqueous solution with phytic acid, and carrying out a reaction after mixing; freeze-drying the reaction product to get said compressive graphene hydrogel.

3. The process of claim 2, wherein the graphene oxide in said aqueous solution is at a concentration of 1-4 mg/mL.

4. The process of claim 2, wherein the aqueous solution after being doped has 1-10 mL of phytic acid for every 60 mL of the aqueous solution.

5. The process of claim 2, wherein the reaction is carried out at a temperature of 120-180° C. for 12-24 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 shows the appearance of the graphene hydrogel prepared by Embodiment 1.

[0016] FIG. 2 shows the scanning electron micrograph image of graphene hydrogel prepared by Embodiment 1.

[0017] FIG. 3 shows the constant current charge-discharge curves of the graphene hydrogel electrode material prepared by Embodiment 1.

[0018] FIG. 4 shows the bar graphs of compressive modulus of graphene hydrogels prepared by Embodiment 6 with different doping contents.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention is further described in the following exemplified embodiments to illustrate the application of the principles of the invention. It is understood that the invention may be embodied otherwise without departing from such principles. The scope of the claims of the present invention expressly should not be limited to such exemplary or preferred embodiments.

Embodiment 1

[0020] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0021] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H.sub.2SO.sub.4:H.sub.3PO.sub.4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min, freeze-dried to get the graphite oxide.

[0022] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 1 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 4 mL of phytic acid, mixed evenly, and then placed in the reaction 12 h at 150° C.

[0023] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water for 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

[0024] The appearance and scanning electron micrograph image of the graphene hydrogel prepared by this embodiment were shown in FIG. 1 and FIG. 2. And FIG. 3 showed the constant current charge-discharge curves of the graphene hydrogel electrode material under the condition of current density of 1 A/g shows. The specific capacitance calculated by formula Cs=(I×Δt)/(m×ΔV) was 237.5 F/g, which meets the requirements of practical application.

Embodiment 2

[0025] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0026] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H.sub.2SO.sub.4:H.sub.3PO.sub.4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min, freeze-dried to get the graphite oxide.

[0027] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 1 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 1 mL of phytic acid, mixed evenly, and then placed in the reaction 12 h at 1501° C.

[0028] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water for 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

Embodiment 3

[0029] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0030] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H.sub.2SO.sub.4:H.sub.3PO.sub.4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min, freeze-dried to get the graphite oxide.

[0031] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 2 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 4 mL of phytic acid, mixed evenly, and then placed in the reaction 12 h at 150° C.

[0032] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water for 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

Embodiment 4

[0033] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0034] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H.sub.2SO.sub.4:H.sub.3PO.sub.4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min. freeze-dried to get the graphite oxide.

[0035] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 4 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 1 mL of phytic acid, mixed evenly, and then placed in the reaction 12 h at 150° C.

[0036] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water for 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

Embodiment 5

[0037] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0038] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H.sub.2SO.sub.4:HPO.sub.4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min, freeze-dried to get the graphite oxide.

[0039] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 4 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 10 mL of phytic acid, mixed evenly, and then placed in the reaction 12 h at 150° C.

[0040] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water for 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

Embodiment 6

[0041] In this embodiment, the present application provides a compressive graphene hydrogel using the following method:

[0042] Step (1) slowly added 3 g of natural flake graphite to 150 mL of sulfuric acid/phosphoric acid (H2SO4:H3PO4=9:1, v/v) mixed acid solution, followed by adding 18 g of potassium permanganate, mixed evenly, raise the system temperature to 50° C., reacted for 12 h, washed the products with hydrochloric acid and deionized water respectively until the pH is neutral and the rotational speed was 11000 r/min, freeze-dried to get the graphite oxide.

[0043] Step (2) added the graphite oxide of Step (1) to the water, obtained aqueous solution of graphene oxide by ultrasonic dispersion, the concentration of the oxidized graphite is 4 mg/mL, took 60 mL of the aqueous solution in the Teflon-lined autoclave, added 1, 2, 4, 10 mL of phytic acid respectively, mixed evenly, and then placed in the reaction 12 h at 150° C.

[0044] Step (3) collected the cylindrical graphene hydrogel by step (2), soaked and washed with deionized water 24 h, obtained the macro porous graphene hydrogel finally by freeze-drying.

[0045] Step (4) FIG. 4 shows the bar graphs of compressive modulus of graphene hydrogels prepared by Embodiment 6 with different doping contents. As can be seen from the figure, with the increase of the doping amount of phytic acid, the compressive modulus of graphene hydrogel has been improved, when the doping amount of phytic acid is 4 mL, the modulus reaches an extreme value (174.8 kPa). Therefore, the graphene hydrogel prepared by the invention can meet the requirements of practical use, and is expected to be a substitute for electrode materials of super capacitors.

[0046] The above is only a preferred embodiment of the invention, equal changes and modification within the scope of the invention patent, all should be the scope of the invention.