Carbon nanofiber (CNF) is used as an electrode material for electrical double layer capacitors (EDLCs), and is being consistently researched to improve its electrochemical performance. However, CNF still faces important challenges due to the low mesopore volume, leading to a poor high-rate performance. In the present study, we prepared the unique architecture of the activated mesoporous CNF with a high specific surface area and high mesopore volume, which were successfully synthesized using PMMA as a pore-forming agent and the KOH activation. The activated mesoporous CNF was found to exhibit the high specific surface area of 703 m2 g−1, total pore volume of 0.51 cm3 g−1, average pore diameter of 2.9 nm, and high mesopore volume of 35.2 %. The activated mesoporous CNF also indicated the high specific capacitance of 143 F g−1, high-rate performance, high energy density of 17.9-13.0Wh kg−1, and excellent cycling stability. Therefore, this unique architecture with a high specific surface area and high mesopore volume provides profitable synergistic effects in terms of the increased electrical double-layer area and favorable ion diffusion at a high current density. Consequently, the activated mesoporous CNF is a promising candidate as an electrode material for high-performance EDLCs.

1. Introduction
 2. Experimental Procedure
  2.1 Chemicals
  2.2 Synthesis of the improved mesoporous structureof carbon nanofiber with high surface area
  2.3 Characterization
  2.4 Preparation of electrodes and electrochemicalcharacterization
 3. Results and discussion
 4. Conclusions
 Acknowledgments
 References

• Young-Geun Lee(Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea)
• Geon-Hyoung An(Program of Materials Science & Engineering, Convergence Institute of Biomedical Engineering and Biomaterials, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea)
• Hyo-Jin Ahn(1Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea 2Program of Materials Science & Engineering, Convergence Institute of Biomedical Engineering and Biomaterials, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea) Corresponding author