Molecular Architecture‐Driven Interfacial Evolution in Porous Organic Polymer Anodes for High‐Rate and Durable Potassium‐Ion Storage

ABSTRACT Unraveling how molecular architecture dictates electrochemical performance is pivotal to advancing porous organic polymers (POPs) as high‐performance anodes for potassium‐ion batteries (PIBs). Conventional design principles centering on bulk potassium storage fail to account for the distinct rate capabilities and cycling stabilities observed among structurally analogous POPs. Herein, we demonstrate that the molecular skeleton of POPs acts as a primary determinant of the formation and evolution of solid‐electrolyte interphase (SEI). By systematically tailoring the π‐conjugation continuity and C═N active‐site density across a series of model POPs, we uncover distinct structure‐interface relationships. A coplanar molecular conformation enhances π‐conjugation, modulating the initial interfacial electron‐transfer kinetics, thereby facilitating the formation of an inorganic‐rich and stable SEI. Furthermore, an optimized density of C═N functionalities provides appropriate K + adsorption strength, preventing localized ionic/electronic accumulation and maintaining long‐term SEI integrity. Consequently, the optimized POP anode delivers a high reversible capacity of 403 mA h g −1 at 0.05 A g −1 , excellent rate capability of 169 mA h g −1 at 3 A g −1 , and outstanding cycling stability of 279 mA h g −1 retained after 3600 cycles at 1 A g −1 . This work bridges molecular‐level design with interfacial chemistry, providing insights for the development of high‐rate and long‐life organic anodes.