Rational fabrication of semi-interpenetrating three-dimensional hierarchical carbon materials for high-performance symmetric supercapacitor
Peng Liang, Ruochen Zhang, Linken Ji, Yaqing Zhang, Xiaolong Dong, Wenrui Zhang, Tiantian Jiao, Xiangping Li
Abstract
Porous carbon materials, characterized by variable surface morphologies , pore structures , crystallinity, and corresponding mechanisms for ion and electron storage and transport, are one of the promising electrode materials for supercapacitors . In this study, ammonium alginate , phenolic resin and calcium ions were introduced to form a nanoscale semi-interpenetrating network structure by sol-gel method. Further, porous carbon materials were prepared through carbonization and KOH activation. By adjusting the activation temperature and alkali-to‑carbon ratio, the activation rules and electrochemical properties of the porous carbon were obtained. Eventually, a coral-like three-dimensional (3D) porous carbon with high specific surface area was constructed. The alkali-to‑carbon ratio and the activation temperature can influence the specific surface area. When the alkali-to‑carbon ratio was 1:4 and the activation temperature was 800 °C, the activated carbon material used as supercapacitor electrode material achieved the highest specific capacitance in an aqueous electrolyte. Moreover, the capacitive performance of a two-electrode capacitor using an organic system as the electrolyte was investigated, and the specific capacitance reached 125.1 F/g at a current density of 0.5 A/g. The carbon material showed good cycling stability in the organic supercapacitor, maintaining >94 % of the initial specific capacitance in a voltage window of 0–2.5 V for 10,000 cycles. This investigation provides a reference for the construction of high-performance 3D hierarchical carbon materials for supercapacitors.