ORCID Profile
0000-0003-3998-5989
Current Organisations
Beijing Institute of Technology
,
Beihang University
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Publisher: IOP Publishing
Date: 08-01-2018
Publisher: Wiley
Date: 21-12-2017
Abstract: To date, graphene-based electric double layer supercapacitors have not shown the remarkable specific capacitance as theoretically predicted. An efficient strategy toward boosting the overall capacitance is to endow graphene with pseudocapacitance. Herein, molecules of hydrolyzed polyimide (HPI) are used to functionalize N-doped graphene (NG) via π-π interaction and the resulting enhanced electrochemical energy storage is reported. These aromatic molecules in monolayer form on graphene contribute strong pseudocapacitance. Paper-like NG films with different areal mass loadings ranging from 0.5 to 4.8 mg cm
Publisher: Elsevier BV
Date: 07-2019
Publisher: American Chemical Society (ACS)
Date: 26-06-2017
Abstract: A novel approach to improve the specific capacitance of reduced graphene oxide (rGO) films is reported. We combine the aqueous dispersion of liquid-crystalline GO incorporating salt and urea with a blade-coating technique to make hybrid films. After drying, stacked GO sheets mediated by solidified NaCl and urea are hydrothermally reduced, resulting in a nanoporous film consisting of rumpled N-doped rGO sheets. As a supercapacitor electrode, the film exhibits a high gravimetric specific capacitance of 425 F g
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2023
Publisher: IOP Publishing
Date: 12-04-2019
Abstract: Plastic film capacitors suffer from low charge storage capacity due to the low dielectric constant of the polymer (<10). We have devised a polyvinylidene fluoride (PVDF) composite film filled with small graphene oxide (GO) sheets that have aromatic molecules attached to their surfaces. The use of 4,4'-oxydiphenol molecules to functionalize graphene sheets is found to have a remarkable effect on enhancing the dielectric permittivity as well as reducing the electrical conductivity of the nanocomposite. When under an electric field, these molecules with an angled molecular geometry act as aligned electric dipoles to largely enhance the dielectric permittivity of the composite, reaching a level two orders of magnitude higher than that of the counterpart filled with blank graphene sheets. Also, the aromatic molecules on the graphene surface act as resistive barriers that block charge transfer between interconnected graphene sheets. As a consequence, the electric conductivity of the composite can be decreased by two orders of magnitude. The PVDF composite filled with functionalized graphene shows a percolation threshold of 13 wt% and a high dielectric constant of 1091 at 100 Hz at this point.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2022
No related grants have been discovered for Dezhi Zheng.