Ultrahigh stability of lithium batteries improved by methoxy-modified graphdiyne composite separators

Methoxy-functionalized graphdiyne (OMe-GDY) significantly suppresses the formation of lithium dendrites by promoting the rapid development of a thin and uniform SEI on the lithium anode surface, maximizes the utilization of the lithium anode surface and enhances stable lithium-ion diffusion and uniform deposition during cycling, greatly improving the safety and performance of the lithium metal electrode. • Blade-coating methoxy-modified graphdiyne for porous bilayer composite separators. • Methoxy-modified graphdiyne establishes a stable lithium-electrolyte interface. • Lithium battery coated with methoxy-modified graphdiyne has long cycle stability. • Methoxy-modified graphdiyne can inhabit lithium dendrites growth. Microprous polyolefin separator membranes play a crucial role in the performance of lithium batteries, but uncontrolled lithium dendritic growth and the high electrolyte reactivity can significantly affect battery performance. This study introduces a novel separator, OMe-GDY@PP, a functional bilayer composite created by blade-coating methoxy-modified graphdiyne onto commercial polypropylene separators. The methoxy-modified graphdiyne carbon network, characterized by superior electronic and ionic conductivity, establishes a stable and heterogeneous lithium-electrolyte interface. This interface facilitates uniform lithium deposition, suppresses dendrite growth, and extends the battery’s lifespan. The OMe-GDY@PP-modified symmetric battery achieves a stable voltage platform for over 3400 h at a current density of 1 mA cm −2 , surpassing the performance of PP separator symmetric batteries by 200 %.