Development and Electrochemical Characterization of a Supercapacitor Based on Vertically Aligned Carbon Nanotubes

Abstract

Supercapacitors, also known as electrochemical capacitors, are energy storage devices that stand out due to their high power density and long cycle life, making them promising for a wide range of technological applications. This work aims to develop and electrochemically characterize a supercapacitor based on vertically aligned multi-walled carbon nanotube (VAMWCNT) electrodes grown directly on metallic substrates by chemical vapor deposition. The synthesized materials were characterized by scanning and transmission electron microscopy, as well as Raman spectroscopy, in order to evaluate their morphological and structural properties. The device was assembled in a coin cell configuration using an aqueous electrolyte and evaluated through cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The results showed homogeneous nanotube growth, graphitic structure with the presence of defects, and predominantly capacitive electrochemical behavior. The voltammetry curves exhibited nearly rectangular shapes, while the galvanostatic measurements indicated linear charge–discharge profiles, with a specific capacitance of 2.3 F·g⁻¹. Impedance spectroscopy revealed low internal resistance and a response close to ideal capacitive behavior. It is concluded that the VAMWCNT-based architecture is functional for supercapacitor applications, presenting performance consistent with the exploratory nature of the study and potential for future optimization.