High-Performance Supercapacitor Materials Based on Hierarchically Porous Carbons Derived from <i>Artocarpus heterophyllus</i> Seed
Subrata Maji, Rashma Chaudhary, Rekha Goswami Shrestha, Ram Lal Shrestha, Barış Demir, Debra J. Searles, Jonathan P. Hill, Yusuke Yamauchi, Katsuhiko Ariga, Lok Kumar Shrestha
Abstract
High-surface area and large porosity carbon materials with hierarchically porous structures are the preferred electrode materials for high-energy density supercapacitors. In this contribution, we report the preparation of ultrahigh surface area nanoporous carbon materials with hierarchically micro- and mesopore structures from Artocarpus heterophyllus (Jackfruit) seed. This involves a potassium hydroxide (KOH) activation method conducted at higher temperatures (600–1000 °C). The resulting amorphous carbon materials display outstanding performance as electrodes in electrical double-layer capacitors with an aqueous electrolyte (1 M H2SO4), which is due to their partially graphitic structures, ultrahigh surface areas of ca. 2104.3 m2 g–1, and large pore volumes of ca. 1.386 cm3 g–1. Electrodes prepared from the material with optimal textural parameters lead to a high specific capacitance of 323.8 F g–1 at 1 A g–1 and sustained 53.7% capacitance retention at a high current density of 50 A g–1, demonstrating the high rate performance of the electrode. The experimental results suggested fast diffusion of the electrolyte ions near the surface of the electrode, which was verified using molecular simulations. The simulations verified that the electrolyte enters the pores, thereby increasing the capacitance but reducing the charge rate compared to nonporous electrodes. Additionally, an exceptionally long cycle stability was observed with 97% of the capacitance retained after 10,000 charge–discharge cycles. The results show the considerable probability of Jackfruit-seed-derived hierarchically porous carbons as the electrode materials for high-performance supercapacitor applications.