Superflexible C-graphyne as a promising anode material for lithium-ion batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 7; no. 29; pp. 17357 - 17365
• Main Authors: Wu, Bozhao, Jia, Xiangzheng, Wang, Yanlei, Hu, Jinxi, Gao, Enlai, Liu, Ze
• Format: Journal Article
• Published: 23.07.2019
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta05955e

The breakthrough in the synthesis of graphyne, graphdiyne and graph-4-yne stimulates interest in studying new members of the graphyne family for promising applications. In this work, a new allotrope of graphyne with excellent stability and an ultrahigh specific surface area of 4255 m 2 g −1 , named C 68 -graphyne, is predicted by first principles calculations. Mechanical tests reveal that C 68 -graphyne exhibits much smaller in-plane tensile stiffness (∼50.5 N m −1 ) and out-of-plane bending stiffness (∼0.5 eV) than graphene (in-plane tensile stiffness 350 N m −1 and out-of-plane bending stiffness 1.4 eV), suggesting C 68 -graphyne as a superflexible material. Meanwhile, our results show that monolayer C 68 -graphyne is a semiconductor with a direct band gap of 1.0 eV, which can be tuned by strain-engineering, and the calculated carrier mobility is as high as 1.81 × 10 5 to 2.97 × 10 5 cm 2 V −1 s −1 at 300 K. Finally, the potential application of C 68 -graphyne as an anode material for lithium-ion batteries is explored and predicted. The calculated results show highly efficient charge transfer from the adsorbed Li ions to C 68 -graphyne yet a low diffusion barrier for Li ions in C 68 -graphyne for fast charge/discharge rates. The storage capacities for Li in monolayer and bilayer C 68 -graphyne are calculated to be as high as 1954 and 1675 mA h g −1 , respectively. These features make C 68 -graphyne a promising anode material for lithium-ion batteries with excellent energy storage capacities as well as fast charge/discharge rates. A new graphyne with high stability, excellent flexibility and carrier mobility is theoretically predicted as a promising anode material for lithium-ion batteries with high capacity.