In a commentary in the journal Joule, a team from the Institute of Chemistry, Chinese Academy of Sciences, suggests that graphdiyne (GDY)—a two-dimensional carbon allotrope that complements the properties of prevailing carbon materials—shows intrinsic advantages as an electrochemical interface.

It draws much attention for its applications in lithium-ion batteries (LIBs), catalysts, solar cells, and electro-chemical actuators. Compared with other carbon materials, GDY has good controllability in terms of its structure and preparation. The synthesis of GDY at low temperature (usually below 100 ˚C) changes the understanding in the preparation of traditional carbon materials, and it can be produced in solution even at various substrate. The size of the in-plane cavities in GDY can be accurately tuned for atomic-level selectivity via varying the terminal acetylenic groups of precursor.

Molecular engineering introduces heteroatoms and functional groups into GDY readily; thus, its intrinsic electronic structure (band gap), optical property, and surface energy are artificially tailorable. It performs high mechanical modulus and stiffness, fulfilling diverse requirements for constructing composite materials.

—Zuo and Li

The ball-and-stick model of a single-layer GDY. Sun et al. (2015)

The team of Professor Yuliang Li and Zicheng Zuo review the key scientific issues and opportunities and provide insight into the challenges related to solving these issues.

Well-defined interfacial defects in catalysts are the critical aspect affecting their performance and reproducibility in fuel cells, water splitting, CO₂ reduction, and so on. The character of GDY allows the production of well-defined defects.

—Zuo and Li

Further, they note, atomic-thick GDY naturally possesses in-plane cavities, high mechanical strength, good conductivity, and good affinity with metal elements; no other material with these properties has been prepared on a large scale. These properties of GDY can potentially solve the interfacial problems in alkali metal batteries such as Li, Na, K, and Mg, they suggest.

Although GDY has strong development potential, there remain several major challenges, the researchers point out.

1. Large-scale preparation of highly crystalline single- and few-layer GDY.

2. Obtaining the atomic phase structure and measuring the intrinsic properties (electronic,optical, acoustic, and magnetic). It is very important to develop methods for the damage-free transfer of GDY film and fabrication of high-quality devices.

3. Theoretical simulation; the correct calculation models are needed for studying the electrochemical mechanism and process on GDY in different applications.

4. Interface analysis: advanced experimental methods for characterizing the interface structure and interfacial synergetic effects.

Resources

• Zuo and Li (2019) “Emerging Electrochemical Energy Applications of Graphdiyne,” Joule doi: 10.1016/j.joule.2019.01.016

• L. Sun, P.H. Jiang, H.J. Liu, D.D. Fan, J.H. Liang, J. Wei, L. Cheng, J. Zhang, J. Shi (2015) “Graphdiyne: A two-dimensional thermoelectric material with high figure of merit,” Carbon, Volume 90, Pages 255-259 doi: 10.1016/j.carbon.2015.04.037