A binder-free multi-walled carbon nanotube electrode containing oxygen functionalities for electrochemical capacitors

Dry Synthesis of Binder-Free Ruthenium Nitride-Coated Carbon Nanotubes as a Flexible Supercapacitor Electrode

Ruthenium nitride was successfully deposited on a multiwalled carbon nanotube (MWCNT) forest grown on a stainless-steel mesh substrate by radiofrequency plasma-assisted pulsed laser deposition. This novel dry fabrication method for flexible supercapacitor electrodes eliminates toxic byproducts and the need for any binder component. Experimental results show a successful thin film coating of the individual MWCNTs with RuN_x under various synthesis conditions. The electrochemical characterization demonstrates a significant improvement in capacitance of the synthesized RuN_x-MWCNT electrode compared to the bare MWCNT forest, with a large potential window of 1.2 V. Capacitance values as high as 818.2 F g^-1 (37.9 mF cm^-2) have been achieved.

Opening the internal structure for transport of ions: improvement of the structural and chemical properties of single-walled carbon nanohorns for supercapacitor electrodes

We investigated the electrochemical performance of single-walled carbon nanohorns (SWCNHs) for use as supercapacitor electrodes. For the first time, we used acid-treatment for oxidation of SWCNHs and hole creation in their structure. A detailed study was performed on the correlation between the oxidation of SWCNHs via acid treatment and variable acid treatment times, the structural properties of the oxidized carbon nanostructures, and the specific capacitance of the SWCNH electrodes. We showed that simple functionalization of carbon nanostructures under controlled conditions leads to an almost 3-fold increase in their specific capacitance (from 65 to 180 F g⁻¹ in 0.1 M H₂SO₄). This phenomenon indicates higher accessibility of the surface area of the electrodes by electrolyte ions as a result of gradual opening of the SWCNH internal channels.

The correlation between the oxidation of single-walled carbon nanohorns (SWCNHs) via acid treatment and the electrochemical properties of the SWCNH electrodes is presented.