The uncontrollable growth of lithium dendrites and the flammability of electrolytes are the direct impediments to the commercial application of high‐energy‐density lithium metal batteries (LMBs). Herein, this study presents a novel approach that combines microencapsulation and electrospinning technologies to develop a multifunctional composite separator (P@AS) for improving the electrochemical performance and safety performance of LMBs. The P@AS separator forms a dense charcoal layer through the condensed‐phase flame retardant mechanism causing the internal separator to suffocate from lack of oxygen. Furthermore, it incorporates a triple strategy promoting the uniform flow of lithium ions, facilitating the formation of a highly ion‐conducting solid electrolyte interface (SEI), and encouraging flattened lithium deposition with active SiO2 seed points, considerably suppressing lithium dendrites growth. The high Coulombic efficiency of 95.27% is achieved in Li–Cu cells with additive‐free carbonate electrolyte. Additionally, stable cycling performance is also maintained with a capacity retention rate of 93.56% after 300 cycles in LFP//Li cells. Importantly, utilizing P@AS separator delays the ignition of pouch batteries under continuous external heating by 138 s, causing a remarkable reduction in peak heat release rate and total heat release by 23.85% and 27.61%, respectively, substantially improving the fire safety of LMBs.

中文翻译：

---

微胶囊改性策略赋予隔膜多功能性以提高锂金属电池的安全性


锂枝晶的不可控生长和电解质的易燃性是高能量密度锂金属电池（LMB）商业应用的直接障碍。在此，本研究提出了一种结合微胶囊和静电纺丝技术来开发多功能复合隔膜（P@AS）的新方法，以提高LMB的电化学性能和安全性能。 P@AS隔板通过凝相阻燃机制形成致密的木炭层，导致内部隔板因缺氧而窒息。此外，它还采用了三重策略，促进锂离子的均匀流动，促进高离子传导固体电解质界面（SEI）的形成，并鼓励具有活性SiO2种子点的扁平锂沉积，从而显着抑制锂枝晶的生长。采用无添加剂碳酸盐电解质的锂铜电池实现了 95.27% 的高库仑效率。此外，LFP//Li电池也保持稳定的循环性能，300次循环后容量保持率为93.56%。重要的是，利用P@AS隔膜将软包电池在持续外部加热下的点火延迟了138秒，导致峰值放热率和总放热量分别显着降低了23.85%和27.61%，大大提高了LMB的防火安全性。