Tag Archive for: reduced graphene oxide (GO)

Scientific publication

Hydrothermal vs. Electrochemical reduction of graphene oxide: A physico-chemical and quartz crystal microbalance study

/in , , /by

Authors: Caroline Keller, Gregory Barbillon, Catherine Debiemme-Chouvy, Ozlem Sel, Hubert Perrot

Journal: Carbon

Abstract

Reduced Graphene Oxide possesses numerous interesting properties, making it one of the most studied materials today. By this way, applications in various fields, including fundamental research, can be found. Nevertheless, the complexity of reduced Graphene Oxide lies in its fabrication process which defines their properties. In this paper, two fabrication methods -electrochemical and hydrothermal reduction of graphene oxide – were compared using physico-chemical and electrogravimetric analysis. Our findings reveal significant morphological differences between the two methods, accompanied by different electrochemical behaviors, when tested in aqueous electrolyte (i.e. 0.5 M Na2SO4). Specifically, electrochemically reduced graphene oxide exclusively involves sodium (whether hydrated or not) in its charge compensation mechanism, whereas hydrothermally reduced graphene oxide also involves proton in sodium sulfate solution.

You can access the full paper here.

Scientific publication

Cation desolvation-induced capacitance enhancement in reduced graphene oxide (rGO)

/in , , /by

Authors: Kangkang Ge, Hui Shao, Encarnacion Raymundo-Piñero, Pierre-Louis Taberna & Patrice Simon

Journal: Nature Communications

Abstract

Understanding the local electrochemical processes is of key importance for efficient energy storage applications, including electrochemical double layer capacitors. In this work, we studied the charge storage mechanism of a model material – reduced graphene oxide (rGO) – in aqueous electrolyte using the combination of cavity micro-electrode, operando electrochemical quartz crystal microbalance (EQCM) and operando electrochemical dilatometry (ECD) tools. We evidence two regions with different charge storage mechanisms, depending on the cation-carbon interaction. Notably, under high cathodic polarization (region II), we report an important capacitance increase in Zn2+ containing electrolyte with minimum volume expansion, which is associated with Zn2+ desolvation resulting from strong electrostatic Zn2+-rGO interactions. These results highlight the significant role of ion-electrode interaction strength and cation desolvation in modulating the charging mechanisms, offering potential pathways for optimized capacitive energy storage. As a broader perspective, understanding confined electrochemical systems and the coupling between chemical, electrochemical and transport processes in confinement may open tremendous opportunities for energy, catalysis or water treatment applications in the future.

 

You can access the full publication here.