High resolution electrochemical micro-capacitors based on oxidized multi-walled carbon nanotubes

Abstract

This study reports the preparation of all-solid-state micro-supercapacitors in planar interdigitated configuration based on MWCNTs via the electrophoretic deposition technique. The carbon nanotubes were functionalized with carboxylic groups via a HNO3 concentric solution in order to prevent their agglomeration and obtain a stable aqueous suspension, and to add a pseudo-capacitance contribution to the predominant double-layer capacitance. The electrode materials were characterized in a 3 electrode configuration, and the micro-devices in a two-electrode configuration using electrochemical impedance spectroscopy and cyclic voltammetry in 0.5 M sulfuric acid and a gel of PVA-H3PO4-H2O doped by SiWA electrolyte. Spatial resolution down to 10 μm was obtained for the device with specific capacitance up to 1.8 mF.cm−2 in electrolyte based PVA and a high power density of 1.28 W.cm−2 in 0.5 M H2SO4 electrolyte.