<scp>DFT</scp> Study of Redox and Metallated States of Quinones for Rechargeable Li, Na, and K Ion Batteries

ABSTRACT Rechargeable Li‐ion batteries are key energy sources for electronics, vehicles, and large‐scale grid applications. Recently, Na‐ and K‐ion batteries have emerged as safer and cost‐effective alternatives. For large‐scale implementation, it is essential to develop efficient electrode materials and gain deeper insights into their mechanisms to enhance capacity and energy density. The quinone‐hydroquinone redox couple is extensively used as an electrode material in metal ion batteries. The redox and protonated states of quinones also facilitate electron and proton transfer in natural energy harvesting processes like photosynthesis. The present study investigates the interaction energies of the redox and metallated states of quinone as well as their electrochemical responses to the binding of Li + , Na + , and K + ions, using 1,4‐benzoquinone (BQ) model system along with corresponding metallic forms. The molecular electrostatic potential (MESP) topographical features are used to explore the binding characteristics of reduced and metallated states of BQ (BQS). Binding energies of the complexes of BQS with Li/Na/K metals and ions are computed using B3LYP/6–311+G(d,p) level of density functional theory (DFT). The reduction of BQ to BQ •– and BQ 2− is found to significantly enhance its binding affinity toward Li + , Na + , and K + ions relative to the neutral BQ form. The observed trend in the BQS interactions, diminishing from Li + to Na + to K + , reflects a decrease in binding affinity with the increase in metal ion radius. The nature of interactions of BQS ··· M + complexes is analyzed by applying Bader's quantum theory of atoms in molecules (QTAIM). The study reveals distinct BQS behavior with the metals/ions, offering insights into the potential of quinones as electrode material in ion batteries.