Temperature-Mediated Engineering of Graphdiyne Framework Enabling High-Performance Potassium Storage

Graphdiyne (GDY), an emerging type of carbon allotropes, possesses fascinating electrical, chemical, and mechanical properties to readily spark energy applications in the realm of Li-ion and Na-ion batteries. Nevertheless, rational design of GDY architectures targeting advanced K-ion storage has rarely been reported to date. Herein, the first example of synthesizing GDY frameworks in a scalable fashion to realize superb potassium storage for high-performance K-ion battery (KIB) anodes is showcased. To begin with, first principles calculations provide theoretical guidances for analyzing the intrinsic potassium storage capability of GDY. Meanwhile, the specific capacity is predicted to be as high as 620 mAh g(-1), which is considerably augmented as compared with graphite (278 mAh g(-1)). Experimental tests then reveal that prepared GDY framework indeed harvests excellent electrochemical performance as a KIB anode, achieving high specific capacity (approximate to 505 mAh g(-1) at 50 mA g(-1)), outstanding rate performance (150 mAh g(-1) at 5000 mA g(-1)) and favorable cycling stability (a high capacity retention of over 90% after 2000 cycles at 1000 mA g(-1)). Furthermore, kinetic analysis reveals that capacitive effect mainly accounts for the K-ion storage, with operando Raman spectroscopy/ex situ X-ray photoelectron spectroscopy identifying good electrochemical reversibility of GDY.