Graphene sheets produced by carbon nanotubes unzipping and their performance as supercapacitor

Carbon nanotubes (CNTs) are well known by their unique properties, such as high electrical conductivity and chemical stability, which can improve charge transfer, facilitating double layer charging in supercapacitor devices. In this work we report on a simple method to unzip CNTs, producing graphene sheets. The amount of hydrogen atoms in the nanotubes synthesis by micro-wave chemical vapor deposition is a critical parameter for unzipping process. High crystalline quality graphene sheets are obtained by this method because of the sp(2) bonds sensibility to hydrogen ions reactivity. Unzipped CNTs provided higher capacitance values without an increase in pseudocapacitance. The resulting structure presented an increase in double-layer charging, suggesting a material with good electron transfer rate. This new synthesis method is promising for obtainment of graphene sheets from carbon nanotubes. Besides, unzipped carbon nanotubes presented themselves to be a good alternative for supercapacitors electrodes material. (C) 2018 Elsevier B.V. All rights reserved.