Flame-retardant separator coated with Boehmite ammonium polyphosphate composite for high-safety lithium-ion batteries

To enhance the thermal stability, electrochemical compatibility, and overshoot protection of separators, it is common practice to incorporate inorganic particles for separator modification. In this work, we discussed a polypropylene (PP) separator that was coated with a combination of hydrothermal boehmite (AlOOH) and ammonium polyphosphate (APP). The coating layer can greatly reduce the thermal shrinkage rate of the separator, enabling the modified separator to retain its original size at 180 °C. In addition, part of the material formed by the decomposition of the coating material at high temperatures can be well-diluted oxygen, thus reducing the risk of combustion. Furthermore, the presence of the coating layer increases the ionic conductivity and electrolyte wettability, thereby improving the cycle stability of the battery. This study utilizes inexpensive, lightweight, and eco-friendly materials to enhance a commercially available polypropylene separator. This modification not only increases the efficiency of material usage but also enhances the economic and environmental advantages of the improved separator. [Display omitted]