Recently, "New Materials" ( ) published online the latest research results of Professor Feng Guang's team from the School of Energy, Huazhong University of Science and Technology on porous graphene supercapacitors. The title of the thesis is " of: of Pore and " (in with: of pore and ); Mo Tangming (17th-grade doctoral student, now an assistant professor at Guangxi University) and Wang Zhenxiang (20th-grade doctoral student) from the School of Energy are the co-first authors, Professor Feng Guang is the corresponding author.

Supercapacitors have the advantages of fast charging and high power and play an important role in the field of energy storage. However, supercapacitors cannot match the energy density of batteries. Improving energy density while maintaining its high power density is a central issue in R&D. Common porous electrode materials (such as activated carbon, carbide-derived carbon, etc.) can increase the energy density of supercapacitors, but will reduce the power density of supercapacitors due to the disordered ion channels. Conductive porous 2D materials with periodic crystal structures and ordered ion channels can help to improve the charging speed and power density of supercapacitors. However, the specific surface area of existing conductive porous two-dimensional materials (such as conductive metal-organic framework materials) is still relatively low, which limits the energy density of supercapacitors. Hydrogen-substituted graphdiyne (GLD) is a new type of porous two-dimensional material, which has broad application prospects in the field of energy storage due to its large specific surface area and stable physical properties. The unique sp and sp2 carbon hybrid orbitals of porous graphene endow it with tunable electronic structure and pore structure, which provides an ideal platform for mechanism research and performance optimization of supercapacitors. Current studies have shown that different stacking methods and different metal properties will profoundly affect the energy storage performance of supercapacitors; however, the specific roles of these topological structures and metal properties and their mechanisms remain unclear.

In response to the above problems, the team combined first principles, isoelectric molecular dynamics simulations, and transmission line models, taking porous graphene as an example, to explore the impact of the stacking method and metal abundance of two-dimensional electrode materials on energy storage in supercapacitors and their Effect mechanism. Simulations show that the AB stack structure with rougher electrode pore walls (forming tortuous nanopores), compared with the AA stack structure (forming straight nanopores), can form stronger superionic states in the pores, thereby increasing The ions in the proportional pores in the free state are conducive to the uncoupling of anion and cation pairs and ion transport, thereby reducing internal resistance and increasing capacitance. It is further predicted that nitrogen or boron doping can transform porous graphene from a semiconductor to a conductor, greatly improving the quantum capacitance of the electrode, making it have both high energy and high power density, and providing a new option for the development of polymer materials. performance supercapacitors.

This work develops a cross-scale model for porous electrode simulation, which is not only applicable to two-dimensional porous graphene electrodes but also can be used in the simulation research of porous materials such as MOF and COF; the results of computational simulation prediction can guide the synthesis of corresponding electrodes in experimental materials, Improve the research and development efficiency of supercapacitors. This work provides new ideas and solutions for the design, optimization, and material screening of supercapacitors.

This work was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Hubei Province, and the academic frontier youth team of Huazhong University of Science and Technology.