Low-temperature plasma-enhanced growth of highly aligned carbon nanotube forests for multifunctional basalt fabrics

This study presents a low-temperature, external catalyst-free method for synthesizing dense forests of vertically aligned carbon nanotubes (VA-CNTs) directly on basalt fabrics, aiming to enhance their effectiveness as structural reinforcements in polymer matrices while imparting additional functionalities, including electrochemical behavior for combined structural and energy storage applications. By systematically varying the processing temperature, the iron oxides inherently present in basalt fibers are found to be uniformly activated as in situ catalysts via hydrogen annealing at 460 degrees C, whereas plasma-enhanced chemical vapor deposition (PE-CVD) allows for the synthesis of VA-CNTs at temperatures as low as 510 degrees C. The optimized PE-CVD process at 460/510 degrees C yields dense, well-aligned VA-CNT arrays with structural quality superior to thermally grown CNTs, while the processing temperatures significantly below conventional CVD temperatures (>700 degrees C) mitigate the thermal degradation of the fiber tensile properties. Electrochemical characterization reveals enhanced capacitive behavior of CNT-modified basalt electrodes combined with a starch-based polymer electrolyte, offering promising prospects for developing sustainable energy storage devices from eco-friendly composite materials based on mineral fibers and biobased matrices.