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.