The first-principle study on the performance of biaxial strained graphdiyne as the Li-ion battery anode

Abstract

Good reversibility and high Li capacity is necessary to be balanced in the electrode materials, the poor cycling performance of Li-ion battery (LIB) is usually caused by the severe volume expansion of anodes during lithiation/delithiation process. The Li storage and diffusion performance of the strained monolayer and bilayer graphdiyne are researched by the density functional theory. The Li capacity of monolayer and bilayer graphdiyne can be improved to 1985 mAh/g under the external 6% biaxial strain, which is much larger than five times of the 372 mAh/g for graphite. The diffusion energy barrier and diffusion coefficient at 300 K of Li atoms on the monolayer and bilayer graphdiyne under the 6% strain is much respectively smaller and larger than that without strain. The volume expansion of the most stable AB-2 stacking bilayer structure after adsorbing Li atoms is only 7%. The remarkable performance of external strained monolayer and bilayer graphdiyne shows that they are promising LIB anodes.