Ultrahigh Capacitive Supercapacitor Derived from Self‐Oxygen Doped Biomass‐Based 3D Porous Carbon Sources

Abstract This study reported an ultrahigh specific capacitance of a supercapacitor, using self‐oxygen doped 3D‐porous carbon derivatives from dried banana leaves. The samples were synthesized by ZnCl₂ impregnation at different temperature pyrolysis of 700–900 °C. Furthermore, the overall process significantly increased the specific surface area from 429.6 to 860.4 m² g⁻¹ followed by the formation of 3D‐interconnected pores structures. Unexpectedly, the activated carbon demonstrated high‐level oxygen dopants between 9.47–12.45%. These valuable physical features showed a ultrahigh specific capacitance of 401 F g⁻¹ and 235 F g⁻¹ in a two‐electrode configuration system, using electrolytes of 1 M H₂SO₄ and 6 M KOH, respectively. Also, electrochemical properties were evaluated in the form of pellet binder‐free materials. Porous carbon sources were known to generate extensive specific energy of 55.69 Wh kg⁻¹ and specific power of 200.09 W kg⁻¹. Based on the technique and results, the use of hierarchical 3D‐porous carbon derivatives is validated as robust electrode materials in developing high‐performance electrochemical energy storage.