The Science Island team has made new progress in the study of highly crystalline graphene macrobodies

Recently, the team of researcher Zhenyang Wang of the Institute of Solid State of the Hefei Institute of Physical Sciences of the Chinese Academy of Sciences has made a series of progress in the covalent growth and electrical behavior modulation of highly crystalline graphene macrobodies. The research was published in the Journal Advanced Functional Materials and Chemical Engineering.

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 application. At present, the conventional preparation methods of graphene macrobodies, such as liquid phase self-assembly, 3D printing and catalytic template method, can only achieve non-covalent weak interaction connections between graphene sheets, resulting in the discontinuity of graphene crystal structure, which has become the main factor limiting the electrical properties of graphene macrobodies.

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 have theoretically revealed its covalent growth mechanism. The covalent growth method enables the material to have a continuous crystal structure and achieves a 100-fold increase in cross-layer conductivity compared to non-covalent assembly. The material helps to solve the problems of layered stacking, crystal quality control, ion transport channel, volume effect and other problems faced by the large-scale application of graphene, laying the foundation for the application of graphene energy storage electrode. Related research results are published in Advanced Functional Materials (Adv. Funct. Mater. , 2023, DOI: 10.1002 / adfm.202305191).

In addition, in order to solve the problem of unsatisfactory conductivity caused by low free electron concentration in the graphene electrode, the researchers introduced copper nanoparticles rich in free electrons into the material system, forming a stable Cu-C bond at the Cu-graphene interface, thus achieving the ultra-high conductivity of the composite material through electron injection. The electrical conductivity reaches 0.37 ×107 S m-1, which is close to that of pure metal, and 3000 times that of pure graphene. Further X-ray absorption fine structure (XAFS) spectroscopy combined with density function theory (DFT) simulation revealed the effect of interface structure on the conductivity, which has important implications for the conductivity modulation of graphene to meet different applications. The research was published in the Chemical Engineering Journal (Chem. Eng. J. , 462, 142319 (2023)) on.

The above work has been supported by the National Key research and development Plan, the National Natural Science Foundation, the Anhui Provincial Science and Technology Major project, and the Anhui Provincial Key research and Development Plan.

Figure 1. layer-by-layer covalent growth and characterization of high crystalline graphene macrobodies.

Figure 2. (a) Conductivity of graphene with different copper content; (b) Graphene carrier mobility and carrier density with different copper content.

Source: Hefei Institute of Physical Sciences, Chinese Academy of Sciences