N-Doped Porous Carbon-Nanofiber-Supported Fe 3 C/Fe 2 O 3 Nanoparticles as Anode for High-Performance Supercapacitors.

Exploring anode materials with an excellent electrochemical performance is of great significance for supercapacitor applications. In this work, a N-doped-carbon-nanofiber (NCNF)-supported Fe 3 C/Fe 2 O 3 nanoparticle (NCFCO) composite was synthesized via the facile carbonizing and subsequent annealing of electrospinning nanofibers containing an Fe source. In the hybrid structure, the porous carbon nanofibers used as a substrate could provide fast electron and ion transport for the Faradic reactions of Fe 3 C/Fe 2 O 3 during charge-discharge cycling. The as-obtained NCFCO yields a high specific capacitance of 590.1 F g -1 at 2 A g -1 , superior to that of NCNF-supported Fe 3 C nanoparticles (NCFC, 261.7 F g -1 ), and NCNFs/Fe 2 O 3 (NCFO, 398.3 F g -1 ). The asymmetric supercapacitor, which was assembled using the NCFCO anode and activated carbon cathode, delivered a large energy density of 14.2 Wh kg -1 at 800 W kg -1 . Additionally, it demonstrated an impressive capacitance retention of 96.7%, even after 10,000 cycles. The superior electrochemical performance can be ascribed to the synergistic contributions of NCNF and Fe 3 C/Fe 2 O 3 .