Scalable structural supercapacitors with graphene-modified high-surface-area electrodes

Electrification, including emerging technologies such as structural supercapacitors, is critical in realizing carbon-neutral transportation. A fundamental challenge is the trade-off between mechanical properties and energy storage capabilities. We report the fabrication of structural supercapacitors with a novel fibre-fibre interface to improve the interlaminar strength and encapsulation while considering the effect of structural resin on energy storage performance. The synthesized graphene nanoplatelets-modified electrodes attain a high specific surface area of ∼231 m 2 ·g -1 - outperforming comparable carbon-based electrodes. We learned that the use of a gel-polymer electrolyte (GPE) separator containing 60 wt% Li-salt eliminates the requirement of electrolyte infusion and showed the highest values for conductivity for the cell produced using GPE. The implementation of glass fabrics (GFs) into the GPE improved the flexural modulus by ∼22%, while retaining the mechanical strength of the cells. The multifunctional performance of the produced SSCs were on par or even outperformed the performances of SSCs reported in literature. A proof-of-concept prototype demonstrates that gel-polymer electrolyte cells can retain charges for longer than those with a glass fibre separator. Cumulatively, these offer the possibility of conventional composite manufacturing techniques to scale-up and eliminate delamination issues arising from different thermal expansion coefficients which also addresses the balance between mechanical stability and electrochemical performance. Our findings support the advancement of durable, lightweight energy storage and delivery systems for sustainable transportation, with potential applications in robotics and wearable technologies.