Efficiently suppressing lithium dendrites on atomic level by ultrafiltration membrane of graphdiyne

Abstract

The cross-plane diffusion of Li+ in 2D materials are helpful to improve the Li nucleation and growth in Li-metal batteries, but it is hard to realize the atomic-level in-plane pores for Li+ migration near the electrode interface due to the uncontrollable formation of pores on prevailing 2D materials. Herein, a large-scale (13 × 11 cm2) ultrathin graphdiyne (GDY) (10 nm) film with naturally atomic-level cavities is first prepared. The ultrathin film is used as co-separator to uniform the interfacial lithium diffusion for lithium plating, and the nucleation overpotential is obviously improved from 115 to 65.4 mV at 0.5 mA cm−2 and 124 to 90 mV at 1.0 mA cm−2, respectively. Associating with the flattening function of this tough 2D film, the lithium dendrites are significantly suppressed, bringing a high Coulombic efficiency (more than 98%) and long lifespan of more than 1200 h at 0.5 mA cm−2 with a high capacity of 2.0 mA h cm−2 on the Cu foil. Theoretical simulation demonstrates that the application of graphdiyne film with atomic-level cavities can produce the single Li+ diffusion near the interface, realizing the highly ordered and uniform migration of Li+, thus effectively increase the anisotropic properties of Li+ diffusion near the electrode, greatly suppressing the lithium dendrites. Beyond, the graphdiyne film shows great promises for accommodating some intractable problems in other alkali metal batteries.