Engineering π‐K ⁺ Interactions in Polycyclic Aromatic Hydrocarbon Anodes via Molecular Jigsaw Strategy for Fast‐Charging Potassium‐Ion Batteries

ABSTRACT Potassium‐ion batteries (PIBs) represent a compelling alternative to lithium‐ion technologies, yet their deployment is hindered by the large ionic radius of K + , which imposes a formidable barrier to reversible and efficient ion storage in conventional anodes. Although organic electrode materials (OEMs) offer intrinsic sustainability, cost‐effectiveness, and structural tunability, they often suffer from severe dissolution and sluggish kinetics. Here, we present polycyclic aromatic hydrocarbons (PAHs) as a new anode platform for PIBs, designed through a molecular jigsaw strategy for π‐electron delocalization engineering. Rational jigsaw screening guided by theoretical calculations, a cyclopentane jigsaw is embedded into naphthalene (N‐PAH) to yield acenaphthylene (A‐PAH), which enlarges π‐conjugation, elevates the LUMO energy level, and strengthens π‐K + interactions. This modification suppresses dissolution and enables a three‐electron transfer process based on the π‐K + storage mechanism. As a result, the tailored A‐PAH anode can deliver 367.2 mAh g −1 at 0.05 A g −1 , along with outstanding rate capability (112.4 mAh g −1 at 5 A g −1 ), and remarkable long‐term stability over 1200 cycles with an ultralow capacity decay of 0.012% per cycle. This work pioneers the application of PAHs as π‐cation‐driven organic anodes for PIBs, laying a solid foundation for designing robust and fast‐charging potassium storage materials.