Whey-protein-derived nitrogen-doped porous carbon has been prepared by preliminary carbonization at 400 °C and final KOH activation at 700 °C combined with catalytic graphitization. Physical characterization indicated that the nitrogen-doped activated electrode material had a large specific surface area (2536 m2 g-1) and plenty of interconnected cavities, which greatly improved the performance of supercapacitors. Electrochemical measurements demonstrated that the as-prepared activated electrode material had exceptionally high capacitance of 248 F g-1 at charge/discharge current density of 0.1 A g-1. Moreover, the prepared supercapacitors exhibited ideal capacitive behavior with nearly no capacitance loss in 6 mol L-1 KOH at different charge/discharge current densities ranging from 0.1 to 5 A g-1 after 1000 charge/discharge cycles. The derived energy density was 12.4 Wh kg-1 at a power density of 495 W kg-1 under operational conditions. These results suggested that the whey-protein-derived porous carbon is a promising supercapacitor electrode material.
Bibliographical noteFunding Information:
This research was funded by following projects: i) “Development of high value carbon based adsorbents from thermochemically produced biochar” 2011-67009-20030 USDA-NIFA Agriculture and Food Research Initiative Sustainable Bioenergy Program , # 2011-67009-20030 , which funded micropore analyzer, electrochemical analyzer and instruments for preparing carbon materials. ii) NSF EPSCoR Track II Dakota BioCon Center , # 1462389 , which supported Mr. Keliang Wang for his PhD study and XPS analysis of carbon samples. iii) The Characterization Facility, University of Minnesota, which received partial support from NSF through the MRSEC program ; iv) National Science Foundation grant CMMI-1462389 , v) The US Department of Energy Bioenergy Technologies Office award # DE-FG36-08GO88073 through the North Central Regional Sun Grant Center at South Dakota State University.
© 2016 Elsevier Ltd.
- Nickel catalytic graphitized
- Nitrogen doped carbon
- Porous carbon