Fire-safe polymer electrolyte strategies for lithium batteries

Over the past decade, the widespread deployment of lithium-ion batteries has led to an increasing number of fire and explosion incidents, posing significant risks to human life and property. These safety concerns are particularly pronounced in high energy density lithium metal batteries, which inhibit their large-scale commercialization. Consequently, addressing battery safety has become a critical research priority. The employment of highly flammable liquid electrolytes (LEs) is a primary contributor to these safety incidents. As such, the development of safer electrolytes for lithium batteries is of paramount importance. Polymer electrolytes (PEs) have emerged as a promising alternative to conventional LEs for next-generation lithium batteries, offering a multitude of advantages, such as exceptional processability and increased flexibility. Despite these benefits, PEs continue to face significant fire safety challenges due to the inherent flammability of polymers and organic solvents. In this review, we provide a comprehensive overview of the advancements in fire-safe polymer electrolytes, elucidating various flame-retardant design strategies and their impact on electrochemical properties. It is anticipated that this review will serve as a valuable reference and offer guidance for the design and development of highly safe polymer electrolyte systems, ultimately fostering further progress in battery safety research.