Design and analysis of ZnO nanoribbon for sodium ion batteries (SIBs)

In this work, we have systematically investigated the two-dimensional ZnO nanoribbon (ZnONR) as anode material for sodium ion batteries (SIBs). First principles calculation is used in order to determine the stability of the structure and electronic properties of pristine ZnONR. Calculation shows that the binding energy (E) of the ZnONR is 5.01 eV, negative value signifies that the substrate is stable. We find favorable Na atoms adsorption site providing maximum storage capacity with stability. Band structure shows that ZnO transformed to metallic nature after adsorption of Na atoms, and it ensures ZnONR shows good charging discharging process. We examine the open circuit voltage, storage capacity, and adsorption energy trend with an increase in Na adsorption on ZnONR. Result shows that when all favorable sites of ZnONR are occupied by Na atoms, adsorption energy per atom changes from 1.29 to 0.64 eV. When Na atoms adsorbed above and below of all the hole sites of the substrate, storage capacity reached its maximum value of 421 mAhg^-1 and open circuit voltage reached its minimum value 0.64 V. Calculations suggest that the diffusion barrier of Na atom is 0.31 eV and follows path 2. These results indicate that ZnONR could be used as potential anode material in SIBs. (author)