Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self-activation of biomass: excellent rate capability and cycle stability
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Fabrication of the nitrogen doped hierarchical porous carbon
        2.2 Electrochemical measurements
        2.3 Characterization
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Zhijian Zhang(School of Materials Science and Engineering, Lanzhou University of Technology)
• Jingjing He(College of Petrochemical Technology, Lanzhou University of Technology)
• Xingchang Tang(School of Materials Science and Engineering, Lanzhou University of Technology)
• Yuling Wang(College of Petrochemical Technology, Lanzhou University of Technology)
• Binbin Yang(College of Petrochemical Technology, Lanzhou University of Technology)
• Kunjie Wang(College of Petrochemical Technology, Lanzhou University of Technology)
• Deyi Zhang(School of Materials Science and Engineering, Lanzhou University of Technology/College of Petrochemical Technology, Lanzhou University of Technology)