Rational Construction of Advanced Potassium Ion Diffusion and Storage Matrix

Developing new electrode materials with a regular channel for stable storage and diffusion of potassium (K) ions is crucial to alleviating the ubiquitous problems in K-ion batteries (KIBs) such as slow diffusion rate, huge volume expansion, and unstable interface by the large K ion radius. Herein, electrode material with a facile diffusion pathway, vast space for volume expansion, and good interfacial compatibility are found to be necessary. Fluoride graphdiyne (F-GDY) is illustrated for its expanded conductive skeleton, uniform structural pores, and well-distributed F atoms. First-principles computations and electrochemical characterizations reveal the high reversible capacity and cyclic stability for the instanced F-GDY electrode through the ultralow diffusion barrier, abundant exposed active sites, and stable KF-enriched solid electrolyte interphase film. The F-GDY anode exhibits a capacity of 320 mAh g⁻¹ at 50 mA g⁻¹, and 120 mAh g⁻¹ at 1000 mA g⁻¹ for 1800 cycles. These electrochemical performances of F-GDY anode are superior than those of many other carbon materials reported to date, providing us with a new insight into the design of an electrode for KIBs.