X-Type Molecular Sieves as a Separator Modification Layer for Stable Lithium Metal Batteries

Commercial separators face significant challenges in mitigating lithium dendrite growth, primarily due to non-uniform lithium ion deposition, which leads to battery performance degradation and raises safety concerns related to separator failure. To address these issues, this study proposes a novel composite separator incorporating two-dimensional (2D) X-type molecular sieves as a functional coating for lithium metal battery separators. The primary objective is to achieve uniform lithium-ion distribution across the surface of the lithium metal anode, thereby effectively inhibiting the formation of lithium dendrites. The results indicate that in comparison to conventional polypropylene (PP) separators, the 2D-X-PP composite separators exhibit substantially improved physical properties, such as enhanced thermal stability, wettability, and tensile strength. In terms of electrochemical performance, cells incorporating the 2D-X-PP separators retained an outstanding 70% of their initial capacity after 1000 cycles, while those employing PP separators retained less than 50% of their capacity after only 500 cycles. These findings provide strong evidence of the exceptional performance of 2D-X-PP and further pave the way for the development of molecular-sieve-functionalized separators in lithium metal batteries.