Mechanistic Insights of Bipolar Redox Cathodes for Organic Rechargeable Batteries: LUMO Anti‒Bonding Contributions

The search for sustainable organic cathode materials has been constrained by intrinsically low redox potentials and limited understanding of p‒type redox chemistry. In this study, we establish a rational design framework for bipolar cathodes by combining p‒type functionalities (‒NH₂, ‒OH, ‒SH) with carbonyl backbones and elucidating their structure‒property relationships using the first-principles calculations. We find that redox potentials and resultant discharging behaviors are governed by the interplay between backbone electron deficiency, p‒type pendant group identity, and solvation stability, in conjunction with charging energy and the lowest unoccupied molecular orbital (LUMO) anti-bonding contributions as principal electronic descriptors. While PF₆ anion-induced decomposition occurs through backbone fluorination and/or locally HF-coordinated bipolar compound generation depending on p‒type functionality, its onset beyond the electrochemical voltage window allows full utilization of both n‒type and p‒type mechanisms. This design strategy enables theoretical charge capacities and energy densities that surpass those of state-of-the-art inorganic and organic cathodes. These insights highlight the underexplored role of p‒type functionalities and provide molecular‒level guidelines for engineering next‒generation, high‒performance organic cathodes.