Phosphonitrile based porous organic polymers as effective flame-retardant electrolytes for lithium battery

Developing electrolytes with flame-retardant properties become the critical factor in making high safety lithium batteries. As phosphonitrile-based compounds are a kind of typical flame-retardant materials, herein, taking phosphonitrile-based aldehyde as the basic organic building blocks, two porous organic polymers (POPs) named as PVPH and PVPH-CO₂H were successfully fabricated after solvothermal reaction with 1,3-diaminobenzene (MPD) and 5-carboxy-1,3-diaminobenzene (MPD-CO₂H), respectively for electrolytes of lithium batteries. Studies revealed that both of the phosphonitrile-based POPs demonstrate good thermal stability and excellent flame-retardant properties, suggesting they are promising flame-retardant electrolytes for the application in battery. Battery performance investigations revealed that both of them, especially PVPH-CO₂H, show good performance after assembling them into lithium batteries. This study paves the way to improve battery safety performance by employing the flame-retardant phosphonitrile-based porous polymers as effective electrolytes. Moreover, it also broadens the application of flame-retardant materials in energy storage materials.