RESUMO
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 Fe3C/Fe2O3 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 Fe3C/Fe2O3 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 Fe3C nanoparticles (NCFC, 261.7 F g-1), and NCNFs/Fe2O3 (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 Fe3C/Fe2O3.
RESUMO
Mn-based oxides are efficient pseudocapacitive electrode materials and have been investigated for capacitive deionization (CDI). However, their poor conductivity seriously affects their desalination performance. In this work, polyaniline coated Mn2O3 nanorods (PANI/Mn2O3) are synthesized by oxidizing a Mn-based metal organic framework (MOF) and subsequent in-situ chemical polymerization. The polyaniline not only acts as a conductive network for faradaic reactions of Mn2O3, but also enhances the desalination rate. PANI/Mn2O3 has a specific capacitance of 87 F g-1 (at 1 A g-1), superior to that of Mn2O3 nanorod (52 F g-1 at 1 A g-1). The hybrid CDI cell constructed with a PANI/Mn2O3 cathode and an active carbon anode shows a high desalination capacity of 21.6 mg g-1, superior recyclability with only 11.3% desalination capacity decay after 30 desalination cycles and fast desalination rate of 2.2 mg g-1 min-1. PANI/Mn2O3 is a potential candidate for high performance CDI applications.