Science Island Team Makes New Progress in The Study Of Macroscopic Bodies Of Highly Crystalline Graphene

Recently, a team of researcher Zhenyang Wang from the Institute of Solid State, Hefei Institute of Materials Science, Chinese Academy of Sciences, has made a series of advances in covalent growth of highly crystalline graphene macrosomes and modulation of their electrical behaviors, and the related research results have been published in Advanced Functional Materials and Chemical Engineering Journal.
Graphene is a two-dimensional carbon material with excellent mechanical, electrical, thermal and optical properties. The efficient preparation and macroscopic assembly of graphene are of great significance for its large-scale applications. Currently, conventional preparation methods of graphene macrosomes, such as liquid phase self-assembly, 3D printing and catalytic template method, can only realize non-covalent weak interaction connection between graphene lamellae, which leads to discontinuity of graphene crystal structure and becomes the main factor limiting the electrical properties of graphene macrosomes.
In view of this, the researchers developed a laser-assisted layer-by-layer covalent growth method to prepare highly crystalline graphene macrosomes, and molecular dynamics simulations theoretically revealed its covalent growth mechanism. The covalent growth method enabled the material to have a continuous crystal structure, and achieved a 100-fold increase in its cross-layer conductivity compared to non-covalent assembly. The material helps to solve the problems of layer stacking, crystal quality regulation, ion transport channels, volume effect and other issues faced by graphene's large-scale application, and lays the foundation for graphene's energy storage electrode application. The related research results were published in Advanced Functional Materials (Adv. Funct. Mater., 2023, DOI: 10.1002/adfm.202305191).
In addition, in order to solve the problem of insufficient conductivity caused by low free electron concentration in graphene electrodes, the researchers introduced free electron-rich copper nanoparticles into the material system, forming a stable Cu-C bond at the interface of Cu and graphene, thus realizing the ultra-high conductivity of the composite material through electron injection, with the conductivity reaching 0.37×107 S m-1, which is close to that of pure metal. The conductivity reaches 0.37×107 S m-1, which is close to that of pure metal and 3000 times higher than that of pure graphene. X-ray absorption fine structure (XAFS) spectroscopy combined with density functional theory (DFT) simulation reveals the effect of interfacial structure on the conductivity, which is of great significance for the conductivity modulation of graphene to meet different applications. The results were published in Chemical Engineering Journal (Chem. Eng. J., 462, 142319 (2023)).
The above work was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Anhui Provincial Science and Technology Major Project, and the Anhui Provincial Key Research and Development Program.