Newtonian Pendulum‐Inspired Fast Kinetics via Potassium Coordinated Molecules for Potassium‐Ion Batteries

Abstract Ions desolvation and diffusion at solid electrolyte interphase (SEI) represent the dominant kinetic limitations that hinder the storage performance of ester electrolytes‐based potassium‐ion batteries (PIBs). Herein, potassium coordinated 3, 4‐dihydroxycinnamic acid (CAK) is reported on the hard carbon (HC) surface, as Newtonian pendulum‐like mediators to regulate desolvation barriers and diffusion capability. The CAK molecules dynamically capture solvated K ⁺ via coordination interaction with energetically favorable desolvation paths and shorten the diffusion distance analogous to the pendulum‐like transport. Simultaneously, the CAK also induces a desirable SEI with more inorganic species, further reducing polarization and accelerating the desolvation process. Benefiting from these advantages, such HC anode delivers a remarkable capacity after 1000 cycles without capacity fading as well as impressive rate performance with 142.2 mAh g ⁻¹ under a high current density of 2000 mA g ⁻¹ . Moreover, the as‐fabricated full battery achieves an energy density of 60.7 Wh kg ⁻¹ at a high rate of 2000 mA g ⁻¹ . This work visually demonstrates the significance of interface design and its association with fast interfacial kinetics for high‐performance PIBs.