Fabrication of hierarchical porous biomass-based carbon aerogels from liquefied wood for supercapacitor applications

Abstract

Hierarchical porous carbon aerogels were synthesized from liquefied wood via physical and chemical activation. The morphology and structure of the KOH treated carbon aerogel (K-LWCA) and steam treated carbon (H-LWCA) were systematically investigated by SEM, N2 adsorption, FTIR, XRD and XPS, and the electrochemical properties were evaluated based on cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The H-LWCA and K-LWCA had the high reached specific surface area (1996 and 1780 cm2 g− 1, respectively) and developed hierarchical porous structures. Compared with H-LWCA, K-LWCA showed the higher specific capacitance, better rate performance and superior cyclic stability due to more defects and hydrophilic functional groups. As expected, the K-LWCA exhibited the optimal mass-specific capacitance of 201.47 F g− 1 at 0.5 A g− 1, and achieved ideal capacitance retention of 70.15% at 20 A g− 1 as well as exceptional cycling stability of 94.11% retention after 5000 cycles. Moreover, the button symmetric supercapacitor device assembled based on K-LWCA demonstrated a specific capacitance of 117.78 F g− 1 at 0.5A g− 1 and presented an energy density of 9.2 Wh kg− 1 at a power density of 375W kg− 1. Accordingly, this work provides a novel approach for the preparation of biomass-derived carbon aerogel electrode materials in practical supercapacitor applications.