Open Access

REVIEW

Advancements and Challenges in Enhancing Thermal Stability of Lithium-Ion Battery Separators: Review on Coating Materials, High-Temperature Resistant Materials and Future Trends

Haoran Li^1,2, Yayou Xu³, Zihan Zhang^1,2, Feng Han^1,2, Ye-Tang Pan^2,*, Rongjie Yang²

1 Qiushi College, Beijing Institute of Technology, Beijing, 102488, China
2 National Engineering Research Center of Flame Retardant Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081, China
3 Research Center for Mine Ventilation Safety and Occupational Health Protection of National Energy Group, Guoneng Shendong Coal Group Co., Ltd., Ordos, 017209, China

* Corresponding Author: Ye-Tang Pan. Email:

(This article belongs to the Special Issue: Grafting to and from Polymer Nanocomposites blends for Coating, Energy and Environmental Applications)

Journal of Polymer Materials 2025, 42(1), 33-55. https://doi.org/10.32604/jpm.2025.062352

Received 16 December 2024; Accepted 27 February 2025; Issue published 27 March 2025

Abstract

The thermal stability of lithium-ion battery separators is a critical determinant of battery safety and performance, especially in the context of rapidly expanding applications in electric vehicles and energy storage systems. While traditional polyolefin separators (PP/PE) dominate the market due to their cost-effectiveness and mechanical robustness, their inherent poor thermal stability poses significant safety risks under high-temperature conditions. This review provides a comprehensive analysis of recent advancements in enhancing separator thermal stability through coating materials (metal, ceramic, inorganic) and novel high-temperature-resistant polymers (e.g., PVDF copolymers, PI, PAN). Notably, we critically evaluate the trade-offs between thermal resilience and electrochemical performance, such as the unintended increase in electronic conductivity from metal coatings (e.g., Cu, MOFs) and reduced electrolyte wettability in ceramic coatings (e.g., Al₂O₃). Innovations in hybrid coatings (e.g., BN/PAN composites, gradient-structured MOFs) and scalable manufacturing techniques (e.g., roll-to-roll electrospinning) are highlighted as promising strategies to balance these competing demands. Furthermore, a comparative analysis of next-generation high-temperature-resistant separators underscores their ionic conductivity, mechanical strength, and scalability, offering actionable insights for material selection. The review concludes with forward-looking perspectives on integrating machine learning for material discovery, optimizing interfacial adhesion in ceramic coatings, and advancing semi-/all-solid-state batteries to address both thermal and electrochemical challenges. This work aims to bridge the gap between laboratory innovations and industrial applications, fostering safer and more efficient lithium battery technologies.

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Keywords

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