Hierarchical Porous Activated Carbon Derived from Coconut Shell for Ultrahigh-Performance Supercapacitors
Yawei Wang, Yuhui Duan, Xia Liang, Liang Tang, Lei Sun, Ruirui Wang, Shunhang Wei, Huanan Huang, Pinghua Yang, Huanan Hu
Abstract
In this research, we successfully produced hierarchical porous activated carbon from biowaste employing one-step KOH activation and applied as ultrahigh-performance supercapacitor electrode materials. The coconut shell-derived activated carbon (CSAC) features a hierarchical porous structure in a honeycomb-like morphology, leading to a high specific surface area (2228 m2 g−1) as well as a significant pore volume (1.07 cm3 g−1). The initial test with the CSAC electrode, conducted in a 6 M KOH loaded symmetric supercapacitor, demonstrated an ultrahigh capacitance of 367 F g−1 at a current density of 0.2 A g−1 together with 92.09% retention after 10,000 cycles at 10 A g−1. More impressively, the zinc–ion hybrid supercapacitor using CSAC as a cathode achieves a high-rate capability (153 mAh g−1 at 0.2 A g−1 and 75 mAh g−1 at 10 A g−1), high energy density (134.9 Wh kg−1 at 175 W kg−1), as well as exceptional cycling stability (93.81% capacity retention after 10,000 cycles at 10 A g−1). Such work thus illuminates a new pathway for converting biowaste-derived carbons into materials for ultrahigh-performance energy storge applications.