Schiff Base-functionalized cobalt-based metal organic framework microspheres with a sea urchin-like structure for supercapacitor electrode material

Abstract

A Schiff base functionalized Co-based metal-organic framework (named Co-L) is synthesized by hydrothermal method at different temperatures, and its application as supercapacitor electrode is studied. The sea urchin-like microspheres with nanorod assembled on its surface can be obtained at 180°C (named as Co-L-180, SBET=137.23m2g−1). In 3M KOH, the Co-L-180 exhibits a specific capacitance of 404Fg−1, at the current density of 1 A g−1. More significantly, the Co-L-180 exhibits outstanding cycle stability. The prepared electrode material is observed to be further activated during the constant charge and discharge cycle, and the capacitance retention rate of the Co-L-180 can achieve to 131% after 50,000cycles, even at a high current density of 10 A g−1. A hybrid super capacitor device is fabricated using the Co-L-180 as positive electrode and active carbon as negative electrode, which achieves an energy density of 21.5Whkg−1 at the power density of 684Wkg−1. The new electrode material Co-L-180 is proved to be suitable for high performance super capacitors.