Patterned Backbone Elongation of Symmetrized Saccharin for Unexpected Enhancement in Redox Activity

Despite significant efforts, the development of sustainable high-performance organic cathodes for Li-ion and Na-ion battery technologies remains a challenge. This study proposes a comprehensive approach to enhance the redox properties and performance of food-inspired saccharin compounds by modifying their redox-active core and backbone, along with functionality-based decoration. Through validated computational protocols, the backbone elongation of saccharin derivatives with symmetrized redox-active cores is achieved, observing an uncommon yet beneficial V-shaped trend in redox potential. This trend is attributed to the "local" inductive effect of the aromatic backbone facilitating electronic transport, which plays a major role in modulating redox chemistry. This suggests that, in contrast to conventional quinones, sufficiently elongated, cyclically beneficial architectures promote enhanced redox activity. Further investigation, screening 40 functional groups, identifies NO, NO₂, NHO, and CN as the top four functionality candidates with exceptional performance and favorable redox activities, offering promise as structurally stable candidates for Na-ion battery technologies. These findings open up new avenues into the design of advanced organic cathodes with high-performance and structural sustainability to develop next-generation energy-storage technologies.