Synthesis Of Two-dimensional Organic Carbon And Nitrogen Materials And Their Applications In Lithium Ion Batteries

Compared with traditional batteries,lithium-ion batteries have the advantages of high energy density,high operating voltage,light weight,small size,small selfdischarge,no memory effect,long cycle life,fast charging,etc.,and because they do not contain heavy metals such as lead and cadmium.Non-polluting,non-toxic materials,known as green new energy products.Therefore,lithium batteries have broad application prospects in many fields such as portable electronic equipment,electric vehicles,space technology,and defense industry.With the deepening of the research on the relationship between the structure and properties of electrode materials,various regular structures or doped composite structures of positive and negative materials designed at the molecular level will strongly promote the research and application of lithium ion batteries.Lithium-ion batteries will be a secondary battery with the best market prospects and the fastest development in the future.Graphyne has excellent electrical,optical and optoelectronic properties,making it a key material for the next generation of new electronic and optoelectronic devices.Graphyne has attracted a wide range of domestic and foreign scientists from the fields of chemistry,physics,materials,microelectronics,electronics,semiconductors and even biology to study its excellent optoelectronic,semiconductor,energy storage,catalysis and mechanical properties.Hexazabenzophenanthrene(HAT)is an electron-deficient rigid planar aromatic disk-like system with excellent ?-? stacking ability.Because it is one of the smallest two-dimensional nitrogen-containing polyheterocyclic aromatic hydrocarbon systems,it has been used as the unit structure for larger two-dimensional N-substituted polyheterocyclic aromatic hydrocarbons.At the same time,its derivatives have been widely studied,suitable for n-type semiconductors,sensors,nonlinear optical chromophores,liquid crystal materials,microporous polymers and energy storage.Based on the above-mentioned development and research status of positive / negative materials,graphyne and HAT derivatives of lithium ion batteries,the work of this paper is as follows:(1)Based on the current research of graphdiyne synthesis and application in batteries,We designed a new kind of nitrogen-doped graphdiyne from the perspective of chemical synthesis.The novel nitrogen-doped graphdiyne was successfully synthesized and applied to the negative electrode of lithium ion battery to improve the charge / discharge stability,life and coulombic efficiency of the lithium ion battery.(2)We designed and synthesized five HAT derivatives and obtained their corresponding single crystal structures.After that,we used these small organic molecules with different stacking modes under different functional groups as the positive electrode materials for lithium ion batteries.By studying the effects of their different molecular packing methods on battery performance,we provide new ideas for the design of high performance environmentally friendly lithium ion battery organic cathode materials.