Statistical Mechanics Model of Interacting Asymmetric Polyatomic Species: Application to the Adsorption of <i>para</i>-Aminobenzoic Acid on a V₂O₅ Surface

Vanadium pentoxide (V2O5) holds significant potential for technological applications in lithium-ion battery. The efficiency and lifespan of these batteries during charging cycles can be enhanced by cathode passivation, for example, using a self-assembled layer of para-aminobenzoic acid (pABA). In this study, the adsorption of pABA on the V2O5 surface was investigated using density functional theory (DFT) calculations. These calculations examined the pABA-surface and pABA–pABA interactions in various adsorption configurations, including molecules in both the first and second adsorption layers. Additionally, a nonideal lattice gas model combined with a statistical mechanics inhomogeneous mean-field approximation, was developed to account for the polyatomic nature of pABA, its asymmetric linear structure, and nearest-neighbor interactions in different adsorption configurations. The partial and overall adsorption isotherms were derived based on the interaction parameters obtained from DFT calculations. The findings reveal that a double-layer, flat configuration predominates at surface saturation, which is consistent with previously reported angle-resolved XPS measurements.