Activated Carbon from KOH-Activation of the Polymeric Product from Cross-Polymerization of Bio-Oil and Furfural as Electrode Material of Supercapacitors
摘要
Bio-oil from pyrolysis of biomass has a high tendency to polymerize at elevating temperature, which thus has the potential to serve as a carbonaceous feedstock to produce functional carbon materials like activated carbon for use as the electrode of supercapacitor. Bio-oil-based activated carbon was formed by cross-polymerization of bio-oil and furfural. Activated carbon was prepared with KOH at a wide temperature range from 500 to 900 °C. The activated carbon was further used as the electrode material of a supercapacitor. The results indicated that the polymeric carbonaceous materials from cross-polymerization of bio-oil with furfural at 200 °C possessed almost no pores. Activated carbon with a specific surface area of 448.8 m2·g− 1 was formed at 500 °C. After the temperature was further increased to 800 °C, the specific surface area was further increased to 2000.8 m2·g− 1. Nevertheless, the continued elevating temperature to 900 °C resulted in the change of the pore structures and reduced the specific surface area to 1648.9 m2·g− 1. The high activation temperature also eliminated the mesopores generated, while the medium temperature of 600 °C retained the mesoporous structures resulting from cracking of aliphatic in the polymeric carbonaceous materials formed. These mesopores were essential for the diffusion of electrolyte ions, rendering the electrode material prepared with the activated carbon obtained at 600 °C better specific capacitance (285.5 F·g− 1), rate performance and cyclic stability.