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.　An　advanced　multifunctional　separator　with　an　extremely　high　electrolyte　adsorption　energy　of　surface　silica　microencapsulated　ammonium　polyphosphate　particles　anchored　in　an　environmentally　friendly　polyvinyl　alcohol　fiber　matrix　is　designed　and　constructed.　The　advanced　separator　demonstrates　excellent　electrochemical　performances,　lithium　dendrite　inhibition,　and　flame-retardant　properties　to　drive　the　development　of　high-performance　and　high-safety　lithium　mental　batteries.　image