3D Porous Activated Carbon Network Derived from Luffa Sponge for Sustainable High‐Performance Supercapacitors

The development of efficient energy storage devices requires the exploration of new, economically feasible, and sustainable electrode materials. To develop high‐performance electrode materials for supercapacitors (SCs), a microwave technique is employed to prepare activated carbon from luffa fibers (biowaste). As a result of the unique luffa network and its macroscopically shaped design, a 3D porous activated carbon electrode is fabricated, and its electrochemical performance is evaluated in a 1 m Na₂SO₄ aqueous electrolyte using a three‐electrode system. Due to the high specific surface area of 3D‐porous microwave‐activated carbons (PMACs) (380 m² g⁻¹), the PMACs exhibit a specific capacitance of ≈290 F g⁻¹ at 2 A g⁻¹, along with excellent cyclability of 89% over 5000 charging/discharging cycles at 20 A g⁻¹. The enhanced electrochemical characteristics of PMACs are attributed to the formation of micro‐/mesoporosity induced by microwave irradiation. A symmetric supercapacitor device (PMACs//PMACs) is constructed, demonstrating an excellent specific capacitance of 75.4 F g⁻¹ at 2 A g⁻¹, a maximum energy density of 26.9 W h kg⁻¹ at 1307.6 W kg⁻¹, and a power density of 48,941.2 W kg⁻¹ at 6.9 W h kg⁻¹, with 80.6% capacitance retention after 5000 charge/discharge cycles.