Application of Graphene Separator in Different Battery Systems

Abstract

The rapid development of the new energy industry has raised higher demands on battery safety and energy density. As a physical barrier between the positive and negative electrodes, the diaphragm's performance directly determines the batteries’ cyclic lifespan and safety margins. The current commercial diaphragms have obvious deficiencies in thermal stability, electrolyte wettability, and mechanical strength. Graphene, with its two-dimensional layered structure, high mechanical strength, and excellent thermal stability, has become a research hotspot for modified membranes. This article outlines the mechanism of action and application progress of graphene-modified separators in different battery systems. In lithium-ion batteries, a graphene coating can enhance the thermal stability and ion conductivity of the separator, thereby improving the battery's cycling performance and safety. In lithium metal batteries, using heteroatom-doped or surface-functionalized graphene separators can effectively inhibit lithium dendrite growth and improve coulombic efficiency. In lithium-sulfur batteries, the graphene functional layer effectively alleviates capacity degradation caused by the shuttle effect through the synergistic action of physical sieving, chemical adsorption, and catalytic transformation. The article finally points out the main bottlenecks currently faced in this field and the directions for future research.