Humic acids-based hierarchical porous carbons as high-rate performance electrodes for symmetric supercapacitors

• Published in: Bioresource technology Vol. 163; pp. 386 - 389
• Main Authors: Qiao, Zhi-jun, Chen, Ming-ming, Wang, Cheng-yang, Yuan, Yun-cai
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2014; Elsevier
• Subjects: Activation; Biological and medical sciences; Biotechnology; butylated hydroxyanisole; Capacitance; Capacitors; Carbon; Carbon - chemistry; Electrodes; Electronics; Fundamental and applied biological sciences. Psychology; Hierarchical porous carbons; Humic acids; Humic Substances; macropores; micropores; Porosity; potassium hydroxide; Precursors; Supercapacitor; Thermogravimetry; Supercapacitor; Activation; Humic acids; Hierarchical porous carbons; Electrodes; High performance; Porosity; Carbon; Humic acid
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2014.04.095

•HAs are used to prepare HPCs via a simple KOH activation process.•Though the mass ratio of KOH/HAs is only 1.5, the obtained HPCs possess high SSA.•The yield of LHA-HPC reaches to 51wt% which is expected to be commercialized.•HPCs are successfully applied as electrode materials in supercapacitors. Two kinds of hierarchical porous carbons (HPCs) with specific surface areas of 2000m2g−1 were synthesized using leonardite humic acids (LHA) or biotechnology humic acids (BHA) precursors via a KOH activation process. Humic acids have a high content of oxygen-containing groups which enabled them to dissolve in aqueous KOH and facilitated the homogeneous KOH activation. The LHA-based HPC is made up of abundant micro-, meso-, and macropores and in 6M KOH it has a specific capacitance of 178Fg−1 at 100Ag−1 and its capacitance retention on going from 0.05 to 100Ag−1 is 64%. In contrast, the BHA-based HPC exhibits a lower capacitance retention of 54% and a specific capacitance of 157Fg−1 at 100Ag−1 which is due to the excessive micropores in the BHA-HPC. Moreover, LHA-HPC is produced in a higher yield than BHA-HPC (51 vs. 17wt%).