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

Abstract

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 (≈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.

Designing and Understanding the Superior Potassium Storage Performance of Nitrogen/Phosphorus Co‐Doped Hollow Porous Bowl‐Like Carbon Anodes

“…Upon potassiation, the ever‐increasing I D / I G ratio suggests the disordered state increases with the insertion of K + . [ 15,41 ] In depotassiation, I D / I G value decreases from 0.92 to 0.87, which is finally close to the initial value (0.85). By contrast, I D / I G value of N‐HPCB increases from 0.87 to 0.93, and decreases to 0.91 before and after potassiation/depotassiation process (Figure S14a, Supporting Information), while that of HPCB is 0.86, 0.94, and 0.92 (Figure S14b, Supporting Information).…”

“…[34][35][36][37] Among them, carbonaceous materials stand out as promising PIB anode candidates owing to their merits of high conductivity, environmental benignity, and good chemical stability. [38][39][40][41] Hard carbon, known as non-graphitic carbon, has been recognized as the most attractive candidate owing to its highly disordered, less crystalline structure together with adjustable interlayer spacing. [42][43][44] However, ubiquitous drawbacks in sluggish reaction kinetics and huge volume expansion during large K + intercalation/extraction inevitably limit its K + storage capability and cycling stability, restricting its practical application.…”

Aggregation‐Resistant 3D Ti3C2Tx MXene with Enhanced Kinetics for Potassium Ion Hybrid Capacitors

“…However, the lack of capable electrode materials hinders the development of PICs, in which an anode with remarkable rate ability is indispensable to match with the fast‐adsorptive cathode such as active carbon. Although some anode materials, such as graphdiyne, [ 4 ] TiO 2 /reduced graphene oxide, [ 5 ] and FeP@C, [ 6 ] show a potential application for K ion storage, rate and long‐term cycling performance of these materials are ungratified due to slow K ion diffusion behavior and terrible material structure stability. [ 7 ] Thus, it is desired to explore suitable anode materials with fast K ion storage behaviors and favorable cyclic stability.…”

Promise and reality of practical potassium‐based energy storage systems

“…Three different stages have been discovered upon potassiation, corresponding to the formation of KC 36 , KC 24 , and KC 8 . [33][34][35][36] In addition to graphite, layered oxides (e.g., K 2 Ti 4 O 9 ) and polyanionic compound (e.g., KTi 2 (PO 4 ) 3 ) also belong to the (de) intercalation type, where K + inserts into the layers or tunnels. 37,38 Anode candidates belonging to conversion type are usually transition metal compounds (TM a X b , TM: transition metal; X: O, S, F, P, N).…”

“…Graphite is a common material that stores potassium throughout the insertion/extraction of K + between graphitic layers. Three different stages have been discovered upon potassiation, corresponding to the formation of KC 36 , KC 24 , and KC 8 33‐36 . In addition to graphite, layered oxides (e.g., K 2 Ti 4 O 9 ) and polyanionic compound (e.g., KTi 2 (PO 4 ) 3 ) also belong to the (de) intercalation type, where K + inserts into the layers or tunnels 37,38 .…”