Breakthrough Makes Lithium Metal Batteries Both Fire-Safe and Long-Lasting

Researchers from Hebei University of Science and Technology, City University of Hong Kong, and Hainan University have achieved a breakthrough in lithium metal battery technology by solving the long-standing conflict between safety and performance. Their innovative approach, detailed in a study published in Carbon Energy, combines a dual-confinement flame-retardant gel polymer electrolyte with a pre-engineered lithium fluoride (LiF)-rich artificial solid electrolyte interphase (SEI) to create batteries that are both inherently fire-safe and exceptionally durable. This strategy specifically addresses the corrosive effects of triphenyl phosphate (TPP), a common flame retardant that typically degrades battery life, by using a coaxial electrospinning technique to create a core-shell structure that physically and chemically confines the TPP while the LiF-rich SEI layer blocks its penetration and protects the lithium metal anode.

The study's findings, accessible via the published DOI, demonstrate remarkable results: lithium metal batteries maintained stable operation for 2400 hours at moderate current densities and 1500 hours at high current densities in symmetric cell tests. In full-cell configurations with lithium iron phosphate (LFP) cathodes, the batteries retained 98.9% capacity after 1500 cycles at 1C and 81.7% capacity after an impressive 6000 cycles at 10C, showcasing exceptional endurance under fast-charging conditions. The lead corresponding scientist emphasized that this precise interface engineering resolves the fundamental trade-off between fire protection and anode stability, enabling reliable operation even with high concentrations of phosphate-based additives. The research was supported by multiple Chinese funding agencies, including the National Natural Science Foundation of China.

This advancement represents a significant step toward practical, high-performance lithium metal batteries for demanding applications like electric vehicles, grid storage, and aerospace systems. The underlying design principle—merging chemical confinement, structural encapsulation, and deliberate SEI engineering—offers a versatile framework that could be applied to other battery chemistries facing similar safety-performance dilemmas. As global demand for energy-dense, safe batteries intensifies, this research provides a promising pathway to accelerate the adoption of lithium metal technologies, potentially transforming energy storage across multiple industries. The work highlights how strategic material science and engineering can overcome critical barriers in next-generation battery development.