This study presents the synthesis of millimeter-tall interconnected cross-linked carbon nanotubes (iCL-CNTs) with high specific capacitance, grown directly on pre-etched Aluminium (Al) substrates. Atmospheric pressure chemical vapor deposition (APCVD) was performed both with and without water assistance at 600℃, utilizing a 20-minute optimized synthesis time and Nickel sulfate (NiSO4) solution coating as the catalyst layer. The growth mechanism of CNTs was highly sensitive to gas ratios, necessitating a systematic investigation of the optimal gas ratios and other CVD conditions. The key to achieving high mass loading of CNTs was found to be the control of NiSO4 volume under optimized gas flow rates and synthesis time. Water-assisted CVD, under optimal gas conditions and synthesis time, yielded millimeter-tall iCL-CNTs with an areal capacitance of 1486mF/cm². Remarkably, under the same parameters, without water assistance, areal capacitance increased significantly to 2471mF/cm². The effects of varying synthesis times on the adhesiveness of the grown CNTs were systematically studied and this study suggests that NiSO4 could be a promising catalyst option, requiring more exploration.