Mechanochemical constructing ordered rhombic channels in graphyne analogues for rapid potassium-ion storage. (30th September 2021)

• Record Type: Journal Article
• Authors: Chen, Yang; Li, Qiaodan; Wang, Wenjie; Lu, Yuxuan; He, Chengli; Qiu, Dong; Cui, Xiaoli
• Is Part Of: 2D materials. Volume 8:Number 4(2021)
• Publication Date: 2021-09-30
• Subjects: graphyne -- potassium-ion battery -- rhombic channel -- mechanochemistry -- rate capability; Graphene -- Periodicals; Materials science -- Periodicals; Nanostructured materials -- Periodicals; 620.115
• DOI: 10.1088/2053-1583/ac26dc
• Languages: English
• ISSNs: 2053-1583

Abstract

Abstract: Constructing a new topological structure with unique ordered channels for rapid potassiation kinetics is crucial to ameliorating the inherent drawbacks of carbon anodes, arising from the large K-ion radius, such as huge volume expansion, slow diffusion rate, and poor interfacial transfer dynamics. Herein, dihydrogen- and nitrogen/hydrogen-substituted rhombic graphynes (HH-rGY, NH-rGY) were synthesized through a mechanochemical cross-coupling method using specific D 2h -symmetric tetrahalogenated organic molecules and alkynyl-containing calcium carbide as precursors. The pyridinic-N atoms in NH-rGY can efficiently manipulate electron distribution and tailor structural arrangement, endowing unique AA′-stacking mode with ordered vertical rhombic channels, broad interlayer spacing of 4.1 Å (1.16 times to that of HH-rGY), and negligible volumetric expansion (<3%) during potassiation, which are studied by experimental investigation and theoretical calculations. Instead of a common capacitive-dominated storage mechanism, intercalation-dominated K-storage is verified in rhombic graphynes by quantitative kinetics analysis. Especially, the NH-rGY electrode delivers a reversible capacity of 230 mAh g −1 at 50 mA g −1 (90.2% after 500 cycles), 97 mAh g −1 at 5 A g −1 and retains 146 mAh g −1 at 2 A g −1 after 5000 cycles, owing to outstanding structural stability and rapid in-plane and inter-layer K + diffusion. This work proposes a universal mechanochemical cross-coupling synthetic methodology and brings new insight into the topological structure design of carbon skeletons for high-performance potassium storage.