In this research, density functional theory (DFT) calculations were carried out for investigating the adsorption of the K atom and ion on the surface of three sheet-like nanoparticles, namely nanosheet, corannulene (CRN) and sumanene (SMN). Density of states (DOS) diagrams, geometry optimizations and total energies were all studied using the M06−2X level of theory with the basis set 6−31+G (d, p). The Ead for SMN-i was found to be more negative, which increased in the following order: SMN-i > nano-sheet > CRN-i > CRN > SMN. The main goal of this work was to compute the cell voltage (Vcell) for K−ion batteries (KIBs). Here, the Vcell for SMN was the highest value, which increased in the following order: SMN > CRN > nano-sheet > SMN-i > CRN-i. The current study provided a theoretical description and promising candidate of the above mentioned nano-structures as anode materials in KIBs ion batteries.