Preparation of 3D-Porous Graphene Aerogel for High- Performance Anode of Lithium-Ion Batteries

Experimental

Materials and Chemicals

All reagents were purchased commercially without further purification. GO was obtained by the method mentioned in our previously reported work [16].

Materials Characterization

To investigate the microstructure and morphology of the asprepared samples, they are examined by advanced characterization tools like X-ray diffraction (XRD, Bruker, Germany), ULTRA 55 scanning electron microscope (SEM, ZEISS, Germany) and Raman spectroscopy (LabRAM HR 800 UV), respectively. The functional groups and elemental analysis of all samples were evaluated by X-ray photoelectron spectra (XPS) on ESCALAB 250Xi (Thermo Scientific, USA).

Electrochemical Measurements

The mixture of active materials, carbon black and polyvinylidene fluoride (PVDF) (weight ratio = 8:1:1) was dissolved in N-methyl- 2-pyrrolidinone (NMP) solvent to prepare working electrodes. The assembling of 2016 coin-type cells was similar to that of reported previously. Cyclic voltammetry (CV) curves were recorded by a Shanghai Chenhua CHI 760e electrochemistry workstation in the range from 3.0 V to 0.01 V at 0.2 mV s-1. Furthermore, galvanostatic charge/discharge cycles were measured using a NEWARE CT-4008 battery testing system at a current density range from 0.05 to 2 A g-1 versus Li/Li+.

Results and Discussion

Structural Characterization

Fig. 1(a) presents the preparation and lithium storage process of the GA. Firstly, 10 mL of GO (3 mg mL-1) was transferred to 25 mL stainless-steel autoclave and then was maintained 180 ℃ for 2, 6, 10, and 14 h. Subsequently, the GA were obtained by freeze-drying and labeled as GA-2, GA-6, GA-10 and GA-14, respectively. The excellent Li+ storage performance of GA-X electrode was due to the porous and defective structure of graphene aerogels, which can provide more Li+ ions pathways and reduce diffusion resistance. In the process of hydrothermal reduction of graphene oxide, oxygen-containing functional groups and hydrogen bonds on the surface of graphene oxide promote cross-linking between the sheets, and the gaps are filled with water molecules [5,17]. As a result, the porous structure is preserved by a sublimation process in freeze drying.

Conclusions

In summary, a simple yet effective hydrothermal approach was reported to synthesize self-assembled porous carbon framework (GA) with prestigious advantages of large surface area, specific porous structure, superior electronic conductivity, excellent mechanical characteristic and ultrafast electron transport kinetic. Benefiting from their surface defects and abundant porosity, the 3D porous graphene exhibits highly stable cycling performance (664.8 mAh g−1 at 0.1 A g−1 after one hundred cycles). Moreover, it is convinced that by controlling the hydrothermal synthesis time, the surface defects of GA can be easily tailored. Correspondingly, GA-6 obtained by hydrothermal reaction for GA-6 exhibits the highest electrochemical performance. The present work provides a simple strategy to the design of electrodes with high performance for LIBs.

Acknowledgements

This work was supported by the National Key Research Plan (2018YFB0604500), the National Natural Science Foundation of China (U1803114), the Key Scientific and Technological Project of Henan Province (202102210183), the China Postdoctoral Science Foundation (207500), Outstanding Foreign Scientists Studio of Coal Green Conversion of Henan Province (GZS2020012), National Natural Science Foundation of China (51974110) and the Program for Science & Technology Innovation Talents in Universities of Henan Province (21HASTIT008).

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
BJSTR

BJSTR

4 Followers

Biomedical Journal of Scientific & Technical Research (BJSTR) is a multidisciplinary, scholarly Open Access publisher focused on Genetic, Biomedical