High-performance nonflammable gel polymer electrolyte with 3D interpenetrating network for advanced lithium-ion batteries

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-08, Vol.493, p.152810, Article 152810
• Main Authors: Du, Yirou, Xie, Yuhui, Chen, Lin, Hu, Fei, Liu, Xianshuai, Yin, Sihao, Jiang, Hao, Liang, Xiaodong, Wu, Feng, Qiao, Liang, Mei, Yi, Xie, Delong
• Format: Article
• Language: English
• Subjects: Gel polymer electrolyte; Lithium ion batteries; MD calculation; P-Si collaborative flame retardancy; Star-shape interpenetration network
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.152810

A novel flame-retardant gel polymer electrolyte (GPE) with a three-dimensional interconnected network is prepared by means of structural modification. Credited to the synergistic flame retardancy of P-Si and the speedy conduction of Li+ ions, the GPE possesses superior safety and excellent electrochemical performance, fully catering to the demands for high stable and energy density in power batteries. [Display omitted] •A nonflammable GPE is synthesized by in-situ copolymerization on cathode electrode.•The star-shape interpenetration network bestowed on GPE a rapid Li+ conductivity.•A P-Si synergic flame retardancy imparts a safety reliability for battery system.•The advantages and mechanisms of Li+ transport are elucidated by MD calculation. Concurrently attaining elevated safety and electrochemical performance in the realm of high-energy–density batteries represents a considerable challenge. Drawing inspiration from the synergistic flame-retardant concept of the P-Si element, a reactive phosphorus-containing flame retardant was meticulously devised that in conjunction with a nano octa-arm crosslinker featuring Si-O-Si and vinyl groups, collectively establishing a star-shaped crosslinked framework to resolve the issue of matrix compatibility and achieving the polymer matrix with intrinsic flame retardancy. Hence, a non-flammable composite gel polymer electrolyte (GPE) was fabricated. The composite GPE-based batteries, encompassing LiFePO4||Li, NCM523||Li and LiFePO4||Graphite, all exhibit commendable cyclic stability under 1C. Furthermore, deriving from the collaborative flame retardant characteristic, pouch cells incorporating the composite GPE displayed remarkable non-flammability and safety characteristics in various tests such as nail penetration, mechanical abuse and ignition scenarios, showcasing a notable 63.3 % reduction in maximum surface temperature. Intriguingly, the insights arising from Molecular Dynamics (MD) simulations indicate the migration mechanism for Li+ within a three-dimensional interpenetrating network, hence unmasking that feasible intra-chain hops of Li+ play a pivotal role.