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

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 x 11 cm(2)) 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. (C) 2018 Elsevier Ltd. All rights reserved.