Spinel Decorated Aligned Carbon Nanotube Arrays As Supercapacitor Electrodes

Accompanying the need for green energy generation is a need for energy storage systems since most green energy sources like solar and wind are intermittent. In recent times, much research focus has been placed on providing more durable and higher capacity energy storage devices like supercapacitors which has led to the design of better electrode materials for these supercapacitors. Graphitic carbon nanomaterials have been tipped as superior materials for making supercapacitors because of their unique electrical properties and pore structure. We report the use of aligned carbon nanotubes as supercapacitor electrodes and highlight their superiority, as a result of a better ordered pore structure, to entangled or randomly oriented carbon nanotubes for electrode applications. Also, the enhanced capacitance of these electrodes after electrochemical decoration with transition metal oxides, specifically spinels, is studied and reported. Specifically, we use Ni-Co mixed oxide and Cu-Mn mixed oxide spinels characterized using EDX and XRD. These spinels have been chosen because of their relatively high electrical conductivity and are optimized for relative metal ratios. Different methods of electrochemical deposition are also explored to achieve uniform coating. Moreover, we reveal a new universally applicable method to preserve pore structure and prevent forest collapse after electrodeposition on carbon nanotube forests that are not free-standing (i.e. not grown with PECVD).