A Foldable Hybrid Supercapacitor with High Energy Density Driven by Cu‐BDC@fMWCNT// Cashew De‐Oiled Shell Derived Activated Carbon

Abstract The development of lightweight and foldable energy storage systems is pivotal for advancing next‐generation automotive technologies. A high‐performance foldable pouch cell supercapacitor is fabricated using Cu‐BDC@fMWCNT as the positive electrode, cashew de‐oiled shell‐derived activated carbon as the negative electrode and a PVA‐KOH/Super‐P gel electrolyte. The device demonstrates an outstanding specific capacity of 163 C g⁻¹ at 1 A g⁻¹, achieving a remarkable energy density of 36.22 W h kg⁻¹ and a peak power density of 4000 W kg⁻¹. Rigorous mechanical evaluations, including 90° and 360° folding tests, confirm excellent foldability and mechanical stability with negligible performance degradation. The superior electrochemical performance arises from the synergistic charge storage mechanisms of the hybrid electrodes, enhancing ion transport and redox activity. The foldable supercapacitor combines exceptional energy storage capabilities with robust mechanical endurance, setting a new benchmark for advanced, high‐performance energy storage devices tailored to the stringent demands for automotive applications.