Proof of Concept Demonstration of a Flame-Resistant Structural Capacitor With Carbon Nanotube Electrodes

Abstract

Structural capacitors are multifunctional energy storage systems that can store energy while acting as structural support. This study focuses on the demonstration of a structural capacitor fabricated using a unique combination of carbon nanotubes and fiberglass prepreg that can function at high temperatures without posing significant risk to the structure. Flat structural capacitors made by curing carbon nanotube electrodes inside glass fiber prepreg demonstrated an average capacitance of ~ 0.33–0.371 nF at 20°C. The capacitors remained operational after exposure to a high-temperature propane torch and demonstrated compliance with the ASTM D6413/D6413M-22 flammability standard. Scaling up of the size of the capacitors to form structural components of aircraft and automobiles can raise the capacitance value to store a significant amount of energy. The structural capacitor will not only enable the aircraft and automobiles to store energy, but will also shield them from electromagnetic interference, allow them endure high temperatures, and provide a strong yet lightweight structural support. Besides, a capacitor can also provide structural health monitoring in real time. This study evaluates the performance of a high-temperature capacitor utilizing fiberglass prepreg as both the dielectric and structural material, with carbon nanotube (CNT) sheets as electrodes. While fiberglass prepreg is widely available, the difficulty of scaling up CNT synthesis has been a major limitation in practical applications. This study also aims to overcome this barrier by presenting a feasible approach for producing CNT sheets at an industrially relevant scale, facilitating their integration into multifunctional structural-electronic components.