Oriented Graphene Based Electrochemical Supercapacitor

Abstract

Graphene has attracted substantial interest as potential carbon electrode material for energy storage applications. Yet, the utility of this material for these applications is governed by its stability and microstructure (i.e., surface area and porosity). Graphene can be prepared in controlled orientation by changing the surface chemistry of GO flakes in suspensions via reduction which causes the graphene to coagulate and self-assemble in specific patterns. Tuning the structure and porosity of oriented graphene is possible by varying the synthesis conditions. Herein, we report the growth of oriented graphene from a relatively small flake size GO suspension. The prepared electrode material demonstrated an excellent electrochemical performance with a supercapacitance value of 195 F g -1 at 1 mV s -1 and low real impedance with good stability and integrity after 4000 cycles of continuous chargedischarge in 1 M KOH electrolyte. This excellent performance is due to the unique architecture of the oriented graphene which comprises micro-slits and meso-channels among the sheets. The meso-channels were suggested to allow rapid diffusion of charge carriers and ions while the micro-slits increase more surface area for electrochemical interactions per unit volume. The observations reported herein create a new understanding of the structure-stabilityperformance trade-off in oriented graphene and layout the foundation for further investigations on their sustainable utilization in energy storage applications.

Electrochemical Performance of Titania 3D Nanonetwork Electrodes Induced by Pulse Ionization at Varied Pulse Repetitions

“…As shown in the Bode plot in Figure 6 b, the total impedance decreases with increasing frequency at low frequency regions. On the other hand, the frequency independent impedance region is observed at higher frequency which is related to the diffusion resistance of electrolyte ions into the electrodes [ 40 , 41 , 42 ]. Generally, at high frequencies, the S2 and S3 electrodes have higher capacitance behavior compared to the control sample (S1).…”