Design Strategies of Polyimide Aerogel Separators for Rechargeable Lithium Batteries

With the ever‐growing demands for efficient energy storage, rechargeable lithium batteries have attracted enormous attention owing to their numerous advantages including high energy density and cycling stability. As one of the critical components, separator governs the ion transport kinetics and plays a vital role in preventing thermal runaway of batteries. However, conventional polyolefin separators are increasingly inadequate to meet practical requirements due to their inherent thermal instability, poor electrolyte affinity, and localized current distribution, which exacerbates lithium dendrite proliferation. In comparison, polyimide aerogel (PIA) separators exhibit outstanding electrochemical stability, thermal stability, and electrolyte wettability, thereby endowing them with great potential toward applications in high‐rate and high‐safety lithium batteries. Recent years have witnessed significant progress in the development of PIA separators for rechargeable lithium batteries. In this review, we summarize the latest advancements in PIA separators, focusing on their design strategies, preparation methods as well as comprehensive performance. Finally, current challenges and future perspectives for the development of PIA separators are discussed.