Nature Seed Pods-Inspired Microstructure Toward Thermal-Mechanical-Electrochemical Robust Separators for High-Safety...

Safety hazards and lithium dendrite growth continue to impede the commercialization of lithium metal batteries (LMBs), exacerbated by conventional polyolefin separators with inadequate thermal stability and poor lithium deposition control. Inspired by the natural protective mechanism of seed pods that combine flexible encapsulation with functional cores, a bio-inspired bean-pod-like aluminum nitride/aramid nanofibers-coated polypropylene separator (B-AlN/ANFs@PP) was developed. Here, aramid nanofibers (ANFs) form a resilient, electrolyte-philic network (the "pod"), while AlN particles (the "seeds") provide thermal-electrochemical dual functionality. This AlN/ANFs@PP separator achieves triple protection for battery performance and safety including a physical barrier against dendrites via ANFs networks, thermal runaway prevention by AlN's heat dissipation, and kinetic enhancement via lithium nitride (Li₃N)-dominated solid electrolyte interphase (SEI) for uniform Li⁺ flux. Consequently, pouch cells equipped with this separator deliver exceptional cycle performance, retaining 88.26% capacity after 500 cycles. This work pioneers a rational polymer-ceramic separator paradigm merging intrinsic safety, dendrite suppression, and long-term stability, paving the way for reliable high-energy LMBs.