The thesis study investigates the effect of Al surface morphology on the growth of inter-connected cross-linked carbon nanotubes for high-energy-density supercapacitors. This study aims to improve the electrochemical performance of supercapacitors by modifying the morphology of Al substrate to increase the surface area.
The study proposes a low-cost yet highly efficient chemical etching technique to modify pristine Al to introduce microstructures on the surface. It explores the impact of time, and temperature on the etched morphology of two different thicknesses of foils (Al-15p, Al-30p). A comparison is made between the samples, by measuring surface roughness using AFM. Furthermore, a systematic study is made by comparing the Ni deposition and CNTs growth on chemically etched foils with the commercially purchased anodic etched Al foils, to evaluate the difference in electrochemical performance based on different etching methods.
The increase in surface area and its effect after CNTs growth is confirmed by the preparation of electrodes using pristine, chemically etched, and commercially anodic etched foils by evaluating the Cyclic Voltammetry curve of electrodes using a 3-electrode setup in an aqueous Na2SO4 electrolyte. The resultant capacitance reveals the chemically etched samples exhibited an increase in surface area by ~1.8 times compared to pristine samples. The etching also proves the better adhesion of CNTs to the modified substrate as compared to the smooth substrate.
Overall, the electrochemical results achieved from the CNTs-grown on chemically etched samples accomplished the capacitance of approximately (Al-15CE:26.50mF/cm2, Al-30CE:24.0mF/cm2), which is comparable to the capacitance of CNTs electrodes made from commercially purchased anodic etched foil (Al-70: 21.0 mF/cm2, Al-30: 21.20 mF/cm2).