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

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.