Humic acids-based hierarchical porous carbons as high-rate performance electrodes for symmetric supercapacitors.
Two kinds of hierarchical porous carbons (HPCs) with specific surface areas of 2000 m(2)g(-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 178 F g(-1) at 100 Ag(-1) and its capacitance retention on going from 0.05 to 100 A g(-1) is 64%. In contrast, the BHA-based HPC exhibits a lower capacitance retention of 54% and a specific capacitance of 157 F g(-1) at 100 A g(-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. 17 wt%).
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Synergetic Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, PR China.
Zhi-jun
ZJ
Qiao
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Synergetic Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, PR China. Electronic address: chmm@tju.edu.cn.
Ming-ming
MM
Chen
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Synergetic Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, PR China.
Cheng-yang
CY
Wang
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Synergetic Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, PR China.
Yun-cai
YC
Yuan
D002244:Carbon / Q000737:chemistry*; D004566:Electrodes; D004581:Electronics; D006812:Humic Substances; D016062:Porosity; D013818:Thermogravimetry
D006812:Humic Substances; D002244:Carbon
Activation; Hierarchical porous carbons; Humic acids; Supercapacitor