This investigation aims at the production of high graphitic, surface area, pore volume and microporous nano-activated carbon from a bioresource (i.e., palmyra palm nutshells) by direct carbonization using metallocene. The modified nano-activated carbon (MNAC) was obtained from the unmodified activated carbon (UMAC) through microwave-assisted sonication technique. The prepared UMAC and MNACs were comprehensively characterized to explore their properties such as surface area and pore volume. The Al-O2 coin cell (2032) batteries were constructed using UMAC- and MNAC-coated copper mesh as an oxygen electrode, in three electrolytes. The electrolytes, namely gel (KOH-PVA), UMAC-gel, and MNAC-gel electrolytes, were used to explore the electrochemical performance of all the constructed Al-O2 coin cell batteries. The electrochemical study of Al-O2 coin cell batteries with MNAC as cathode in MNAC-gel electrolyte shows an enhanced performance than other two Al-O2 coin cell batteries. The outcome of this study also indicates the possible use of MNACs into supercapacitors and other battery systems.