Breath-Figure-Derived Porous Hybrid Layers for Safety-Enhanced Separators in Lithium-Ion Batteries

Abstract

Ensuring both safety and high electrochemical performance in lithium (Li)-ion batteries (LIBs) critically depends on overcoming the intrinsic thermal vulnerability and poor ion-transport properties of commercial polyolefin separators. Although ceramic-coated separators have been widely adopted to mitigate these limitations, conventional approaches often suffer from pore blocking, reduced electrolyte uptake, and diminished flexibility arising from binder swelling and high inorganic loading. Here, we present a static breath-figure self-assembly strategy to construct a highly ordered porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVH)-boehmite hybrid layer on a polyethylene (PE) separator, wherein the PVH matrix forms a regular pore lattice and the boehmite particles are uniformly embedded within the pore walls. The porous PVH architecture ensures excellent electrolyte affinity while preserving open ion-transport pathways without blocking the intrinsic pores of the PE substrate. Simultaneously, the boehmite-rich inorganic framework functions as a robust thermal scaffold that suppresses high-temperature shrinkage and provides rapid self-extinguishing behavior through endothermic dehydration. Furthermore, the Lewis-acidic boehmite surface immobilizes electrolyte anions, thereby promoting selective Li + migration. By synergistically integrating these multifunctional attributes, the breath-figure-derived layer overcomes fundamental limitations of conventional separator designs and establishes a scalable route toward nextgeneration LIBs for uncompromising safety and high performance.