Vertically aligned carbon nanotubes on aluminum foils from biosourced precursors: Application to energy storage

Vertically aligned carbon nanotubes (VACNTs) are among the nanomaterials recognized as efficient for many applications, such as thermal management or energy storage. Since they are mainly produced from hydrocarbon precursors, one of the issue is to reduce the carbon footprint of their synthesis by using bio-sourced precursors. Herein, we use bio-based carbon precursors to effectively grow VACNTs on aluminum thin foils from a one-step catalytic chemical vapor deposition (CCVD) method. This process at moderate temperature and atmospheric pressure is cost-effective and produces good-quality VACNTs on a large scale. We show that we can replace C₂H₂ with bio-sourced carbon precursors, and also toluene, which acts as a solvent for ferrocene, with more eco-friendly solvents. We observe that the activation energy of the growth process depends significantly on the precursor. After a selection of compatible carbon precursors and a parametric study, a 100 µm high VACNT carpet was obtained on Al foils with ethylene and butanol as carbon precursors and ferrocene solvent respectively. The VACNT samples were directly tested as supercapacitor electrodes. The results show that the volumetric capacitances obtained with bio-based precursors match those obtained with acetylene as the carbon precursor.