Redox-Active Macrocycles for Organic Rechargeable Batteries

Organic rechargeable batteries, composed of redox-active molecules, are emerging as candidates for the next generation of energy storage materials because of their large specific capacities, cost effectiveness, and the abundance of organic precursors, when compared with conventional lithium-ion batteries. Although redox-active molecules often display multiple redox states, precise control of a molecule’s redox potential, leading to a single output voltage in a battery, remains a fundamental challenge in this popular field of research. By combining macrocyclic chemistry with density functional theory calculations (DFT), we have identified a structural motif that more effectively delocalizes electrons during lithiation events in battery operations—namely, through-space electron delocalization in triangular macrocyclic molecules that exhibit a single well-defined voltage profile—compared to the discrete multiple voltage plateaus observed for a homologous macrocyclic dimer and an acyclic derivative of pyromel...