Nanostructured Composites Based on Highly Porous Carbon Matrixes Filled with Cobalt and Nickel Hydroxides

The paper considers properties of nanostructured composites for supercapacitors electrodes. The materials are based on multi-walled carbon nanotubes obtained by pyrolysis of the propane-butane mixture (CNT-1) and additionally aged in argon atmosphere (CNT-2). The resulting CNT are filled with cobalt and nickel hydroxides nanoparticles deposited on the surface and in channels composing nanotube fibres. The composites were explored through transmission electron microscopy, X-ray diffractometry, X-ray Fluorescence Element Analysis, and Small-Angle X-ray Scattering. Electrochemical properties of the resulting nanocomposites were examined. As shown, both introducing cobalt-nickel hydroxide into the carbon matrix and functionalizing its surface by ozonation facilitates an increase in the electrical capacity of composite electrodes. This is driven by the pseudocapacitance of nickel-cobalt hydroxides generated as a consequence of reversible redox processes with the involvement of oxyhydroxide phases formed upon cell charge-discharge.