Single‐Atom Zirconium Coordination Polyimide Aerogel as Separator Coating Toward High‐Rate Lithium Metal Battery

Abstract Developing high‐rate lithium‐metal battery (LMB) with superior energy density and operation durability is of significance, which shows enormous potential to be extensively applied. However, the commercialized polyolefin separators exhibit inferior ability to resist the elevated internal temperature and inhibit the lithium (Li) dendrite growth, especially for LMBs under high‐rate operations. With undesired Li⁺‐anion solvated structures in the electrolyte, previous separator modification strategies usually meet a dilemma to simultaneously increase the Li⁺ transference number and decrease the anion transference number. Here, a facile and scalable strategy are reported to prepare high‐performance sandwiched separators with polyolefin separators coated by single‐atom zirconium coordination polyimide aerogel (Zr‐PIA) layers, which can achieve a stable LMB operation at 20 C for 2700 cycles with a capacity retention of 94.6%, substantially outperforming its counterpart separator without Zr. Both the experimental and theoretical studies suggest that the Zr‐PIA layer with nanoporous architecture and anion‐trapping Zr sites can effectively increase the Li⁺ transference number without sacrificing the overall ion conductivity, enabling a rapid, selective and uniform Li⁺ flux through the separator. Such features can facilitate homogeneous the Li nucleation/deposition and mitigate Li dendrite growth, leading to enhanced battery durability and safety.