Luffa vines-derived N, O doped porous carbon with high surface area for supercapacitors

Considerable attention has been devoted to creating porous carbons with exceptional surface area and porosity from biomass waste for energy storage devices. Herein, we employed a straightforward high-temperature carbonization and KOH activation method to synthesize nitrogen (N) and oxygen (O) co-doped porous activated carbons derived from luffa vines (LVACs). The impact of varying KOH concentrations on the morphology, structure, and electrochemical properties of LVACs was thoroughly investigated. The optimal mass ratio of KOH to LVACs at 1:6 achieved the maximum specific surface area of 3369 m2 g−1. At a current density of 1 A g−1, the LASC-6 electrode exhibits an impressive specific capacitance of 348.5 F g−1. It also demonstrates exceptional rate performance, retaining 70.6 % of its capacitance at a current density of 20 A g−1. The electrode possesses robust cycling stability, retaining 90 % of the initial capacitance after 5000 cycles. We assessed the practicality of LVAC-6 by constructing symmetric supercapacitors (SSCs) using KOH and [BMIM]BF4 electrolytes. The KOH and [BMIM]BF4 SSCs achieved specific capacitances of 86.75 and 50.31 F g−1, respectively, at a current density of 0.25 A g−1. Moreover, the [BMIM]BF4 SSC exhibited an impressive energy density of 51.05 Wh kg−1 at a power density of 346.15 W kg−1. Therefore, we propose a simple and cost-effective strategy to produce porous carbon materials with excellent electrochemical performance from discarded biomass waste, facilitating the preparation of environmentally friendly electrode materials for high-performance supercapacitors. •High KOH activator concentrations boost the surface area and microporous volume of LVAC.•The N, O co-doped LVAC-6 achieves an ultrahigh surface area of 3369 m2‧g−1 and a micropore volume of 1.42 cm3 g−1.•LVAC-6 electrode exhibits a superior specific capacitance of 348.5 F g−1 (1 A g−1) and a rate performance of 70.6 % (20 A g−1).•Symmetric supercapacitor delivers a high energy density of 51.05 Wh kg−1 at a power density of 346.15 W kg−1.