Surface and Electrochemical Properties of Radially Oriented Multiwalled Carbon Nanotubes Grown on Stainless Steel Mesh

Abstract

We report on the direct growth of radially oriented multiwalled carbon nanotubes (ROMWCNTs) on stainless steel (AISI 304L) fine-mesh substrate using the chemical vapor deposition (CVD) method to get a stable scaffold for supercapacitors using redox-active materials (e.g., metallic oxides and conducting polymers). The scaffold was characterized by different 'ex situ' (e.g., scanning and transmission electron microscopy, Raman, X-ray photoelectron and energy dispersive spectroscopy, surface area, and porosity analyses) and 'in situ' (e.g., cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy) techniques. We explore this data to identify the origin of capacitance observed. Morphology factor (ϕ) parameter revealed that only 16% of the energy stored in the electrical double-layer is confined in the inner surface regions of the scaffold. It was verified a substantial contribution of the reversible solid-state surface faradaic reactions (RSFRs) to the overall specific capacitance observed. The coin cell was characterized by low equivalent series resistance, fast RSFRs, and very high stability during the galvanostatic charge-discharge experiments. All these results encourage further developments using the ROMWCNTs:AISI fine-mesh composite as a promising scaffold for applications in supercapacitors devices using redox-active materials.