Metal-Organic Framework-Derived CoOx/Carbon Composite Array for High-Performance Supercapacitors.

Abstract

Metal-organic frameworks (MOFs) and their derivatives are promising materials for energy conversion and storage. This study demonstrates a solvent-free method to fabricate a CoOx/carbon composite array derived from ZIF-67 for asymmetric supercapacitors. Tree-like Co metal arrays are electrodeposited on a surface and then directly converted into composite ZIF-67/Co-based MOF arrays via a chemical vapor deposition method (MOF-CVD). Finally, the CoOx/carbon composite array is obtained by regulated calcination of the ZIF-67/Co composite array. The as-prepared CoOx/carbon composite arrays provide a less tortuous pathway for ion diffusion, high pseudocapacitance from transition-metal oxides, and good electrical conductivity from carbon. Moreover, the absence of adhesives in array electrodes is also beneficial to the promotion of the electrochemical performance. The as-fabricated CoOx/carbon composite array electrode shows excellent electrochemical performance with high energy density, high power density, superior rate capability, and long cycle life in an asymmetric supercapacitor. These MOF-derived composite arrays are promising candidate materials for power sources because of their good electrochemical performance.