Design And Preparation Of Functional Graphyne And Its Application Of Electrochemical Energy Storage

Graphitic alkyne composed of sp and sp² carbon atoms is a new allotrope of graphite,which has a largerπ-conjugated structure,abundant natural pores,high stability and wide intrinsic band gap.It shows good application potential in rechargeable battery system,including metal ion battery,metal sulfur battery and metal air battery.The research of graphdiyne（GDY）materials has promoted the rapid development of electrochemical materials.In recent years,the structure and properties of pure GDY have been widely explored and reported.At present,the main methods for functional design of GDY include heteroatom doping,charge transfer doping and defect doping,among which heteroatom doping is considered to be a direct and effective method.The electronegativity difference between heteroatoms and carbon atoms can regulate the electronic structure,interfacial chemical activity and topological defects of GDY materials.In this paper,by changing the polymerization mode of graphitic acetylene monomer or introducing highly reversible carbonyl structure of REDOX between the alkyne bonds,the graphitic acetylene was modified and designed to further improve the performance of graphitic acetylene,and also provide a way of thinking for the functional design of graphitic acetylene.The main research contents are as follows:（1）Synthesis and electrochemical energy storage application of Rhombus-graphyne（R-GY）with diamond-shaped pores.Based on the Glaser coupling reaction,R-GY（R1-GY,R2-GY）materials were prepared on copper sheets by two synthetic routes.Select the appropriate solvent and pre-load the Pd catalyst on the copper sheet to avoid the self-polymerization of 1,3,5-triacetylenebenzene/1,2,3,4,5,6-Hexaethynylbenzene on the copper sheet.XPS analysis showed that the ratio of C（sp²）/C（sp）in R1-GY and R2-GY materials was very close to the theoretical value.After XRD characterization,R1-GY and R2-GY were found to have high crystallinity.Through HR-TEM characterization,it was found that the lattice spacing of R1-GY and R2-GY was 0.22 nm,and the layer spacing was 0.34 nm,which coincided with the XRD peak.R1-GY and R2-GY have a specific surface area of 350 m²/g,which can provide active sites for metal ions and improve electrochemical performance.The reversible specific capacity of Libs at 50 m Ag^-1 for R1-GY and R2-GY materials is2000 m Ahg^-1.（2）Synthesis of Carbonyl-rich Graphdiyne（CR-GY）and its application in electrochemical energy storage.The carbonyl group is highly reversible in REDOX.By designing suitable synthesis route,the carbonyl group is successfully introduced into graphite diyne（GDY）structure.Through XPS characterization,it is found that the C/O ratio in CR-GY materials is consistent with the theoretical value.Through HR-TEM characterization,it is found that the CR-GY material has high crystallinity,and the C and O elements are uniformly distributed in the CR-GY material,and its lattice spacing is about 0.45 nm.Through BET test,it was found that its specific surface area（SSA）was as high as 498.5 m²/g,and it had a rich microporous structure.This provides sufficient paths for metal ion diffusion,which in turn improves the electrochemical performance of the battery.At 50 m Ag^-1,the reversible specific capacity of LIBs is2210 m Ahg^-1,and at 5 Ag^-1,there is still a specific capacity of 451 m Ahg^-1.