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Yang et al. Energy Mater 2024;4:400061 Energy Materials
DOI: 10.20517/energymater.2023.144

Review Open Access

Design strategy towards flame-retardant gel polymer

electrolytes for safe lithium metal batteries

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Borui Yang , Ting Li , Yu Pan , Liu Yang , Kun Li , Jiahao Chen , Zhongfu Yan , Anjun Hu 1,2,* , Jianping
Long 1,*
1
College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, Sichuan,
China.
2
College of Computer Science and Cyber Security, Chengdu University of Technology, Chengdu 610059, Sichuan, China.
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Authors contributed equally.
*Correspondence to: Dr. Anjun Hu, College of Materials and Chemistry & Chemical Engineering, Chengdu University of
Technology, 1#, Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, China. E-mail: anjunhu@cdut.edu.cn; Prof./Dr. Jianping Long,
College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, 1#, Dongsanlu, Erxianqiao,
Chengdu 610059, Sichuan, Sichuan, China. E-mail: longjianping@cdut.cn
How to cite this article: Yang B, Li T, Pan Y, Yang L, Li K, Chen J, Yan Z, Hu A, Long J. Design strategy towards flame-retardant
gel polymer electrolytes for safe lithium metal batteries. Energy Mater 2024;4:400061. https://dx.doi.org/10.20517/
energymater.2023.144
Received: 31 Dec 2023 First Decision: 3 Apr 2024 Revised: 6 May 2024 Accepted: 3 Jun 2024 Published: 11 Jun 2024
Academic Editor: Xiongwei Wu Copy Editor: Fanyuang Liu Production Editor: Fanyuang Liu

Abstract
The emergence of lithium metal batteries (LMBs) as a promising technology in energy storage devices is attributed
to their high energy density. However, the inherent flammability and leakage of the internal liquid organic
electrolyte pose serious safety risks when exposed to heat. In response to this challenge, gel polymer electrolytes
(GPEs) have been developed to mitigate leakage and enhance nonflammability by incorporating flame-retardant
groups, thereby improving the safety of LMBs. This review commences with a brief analysis of the thermal runaway
mechanism specific to LMBs, emphasizing its distinctions from that of lithium-ion batteries. Following this, the
various methods employed to assess the safety of LMBs are discussed, including flammability, thermal stability,
and abuse assessment. The following section categorizes recent research on safe GPEs according to different flame
retardancy levels providing a concise overview of each category. Finally, the review explores current advancements
in developing safety-oriented GPEs and considers potential future research directions.

Keywords: Lithium metal batteries, gel polymer electrolytes, flame retardant, thermal runaway

© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0
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