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

Abstract

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 %.