A three-dimensional graphene-c 3 no 4 Composite material and its preparation method and application, half cell
A composite material and graphene technology, applied in the field of lithium-ion batteries, can solve problems such as the inability to effectively alleviate the severe side reactions between lithium metal and electrolyte, the large specific surface area of three-dimensional electrodes, and instability
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[0025] The invention provides a three-dimensional graphene-C 3 N 4 A method for preparing a composite material, comprising the following steps;
[0026] The graphene oxide dispersion is mixed with dicyandiamide to obtain a mixed solution;
[0027] Freeze-drying the mixed solution to obtain a solid precursor powder;
[0028] Under an Ar atmosphere, the solid precursor powder is calcined to obtain the three-dimensional graphene-C 3 N 4 composite material.
[0029] In the invention, the graphene oxide dispersion liquid is mixed with dicyandiamide to obtain a mixed solution.
[0030] figure 1 Prepare three-dimensional graphene-C for the present invention 3 N 4 Flow chart of composite materials.
[0031] In the present invention, the mass ratio of graphene oxide to dicyandiamide in the graphene oxide dispersion is preferably 5-10:10-60, more preferably 1:12, 4:15 and 1:1. In the present invention, the concentration of the graphene oxide dispersion liquid is not particular...
Embodiment 1
[0045] First, 50 mL of graphene oxide dispersion with a concentration of 2 mg / mL and dicyandiamide (mass ratio of graphene oxide to dicyandiamide: 80 mg:300 mg) were stirred and mixed at 80° C. for 2 h, and then the resulting homogeneous and clear solution was Freeze-drying (freeze-drying parameters: -50°C, vacuum degree of 5Pa, drying time of 20h) to obtain solid precursor powder, then placed in a high-temperature tube furnace, under an Ar atmosphere at a heating rate of 5°C / min to 550°C and hold for 2 hours to obtain 3D graphene-C 3 N 4 composite material.
[0046] For the obtained three-dimensional graphene-C 3 N 4 The composite material was tested by scanning electron microscopy, and the structure is shown in Figure 2. figure 2 The middle a and b are scanning electron micrographs under different magnifications respectively. It can be seen that after freeze-drying and calcination, the three-dimensional graphene-C 3 N 4 The composite material presents a three-dimensi...
Embodiment 2
[0056] Same as embodiment 1, difference is only in the mass ratio 50mg: 600mg of graphene oxide and dicyandiamide, utilizes the three-dimensional graphene-C that embodiment 2 makes 3 N 4 The composite material is used as a lithium metal negative electrode, assembled with a lithium sheet to form a half-cell, and the electrochemical performance is tested. The results are as follows: Figure 4 , it can be seen that due to the large proportion of dicyandiamide added, the final three-dimensional graphene-C 3 N 4 C in composite 3 N 4 High content, at 1mAh / cm 2 and 1mA / cm 2 Under the test conditions, it can cycle 30 times.
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