Porous Fe3O4/C nanoaggregates by the carbon polyhedrons as templates derived from metal organic framework as battery-type materials for supercapacitors

Abstract

The porous Fe3O4 nanoaggregates were fabricated by the carbon polyhedron as templates through the hydrothermal method. The carbon polyhedron was obtained by the carbonization of ZIF-67 and subsequent acid treatment. The finial porous Fe3O4 nanoaggregates possess high specific area of 547.5 m2 g−1 with pore volume of 0.375 cm3 g−1. Such unique structures facilitate electrode materials fully exposed to electrolyte solution and maintain the structural stability during fast electrochemical reaction processes. Thereby, porous Fe3O4 nanoaggregates exhibit high specific capacity of 868.7 C g−1 at 2 A g−1 in the wide potential window of −0.90 - 0.45 V in 3 M KOH. After 3000 cycles at 2 A g−1, the electrode material retains 771.8 C g−1. Even at high current density of 20 A g−1, the electrode still delivers 456.1 C g−1, which is outstanding of other Fe3O4 nanomaterial for supercapacitor. Furthermore, the Fe3O4//AC asymmetry supercapacitor (3 M KOH as electrolyte) exhibits high energy density of 24.2 Wh kg−1 at power density of 801.1 W kg−1 with excellent cycling performance.