As　the　＂safety　switch＂　of　lithium　batteries,　the　separator　controls　the　electrochemical　performance　and　safety　performance　of　lithium　batteries.　However,　highly　flammable　and　easy　to　induce　lithium　dendrite　generation　of　commercial　polyolefin　pose　a　huge　safety　hazard　for　current　commercial　lithium-ion　batteries.　Therefore,　developing　a　flame-retardant,　lithium　dendrite-inhibiting　separator　can　achieve　further　leap　in　the　lithium　battery　industry.　A　＂sandwich＂　separator　(SPS-B)　is　designed　by　integrating　silk　fibroin　(SF),　decabromodiphenyl　ethane,　and　polyvinyl　alcohol　through　electrospinning.　SPS-B　shows　excellent　flame-retardant　properties　through　a　free　radical　trapping　mechanism.　Moreover,　the　SPS-B　demonstrated　satisfactory　capability　of　suppressing　lithium　dendrites　by　constructing　Li3N-SEI　with　high　ionic　conductivity　and　high　strength,　and　the　secondary　structure　beta-sheets　of　SF　can　inhibit　the　＂tip　effect＂　of　lithium　dendrites,　which　enables　efficient　lithium　plating/stripping　in　Li//Li　and　Li//Cu　cells.　In　addition,　the　enhanced　porosity,　electrolyte　affinity　of　SPS-B　promotes　excellent　electrochemical　performance　with　enhanced　discharge　capacity　and　reduced　concentration　polarization.　Finally,　fire　risk　of　soft-pack　batteries　are　evaluated　by　continuous　external　heating.　Compared　with　commercial　separator,　soft-pack　batteries　with　SPS-B　show　much　lower　heat　release　rate,　peak　temperature　and　flue　gas　release　rate,　further　confirming　the　effectiveness　of　SPS-B　in　reducing　fire　risk.　Overall,　the　SPS-B　provides　a　satisfactory　way　to　develop　high-performance　and　superior　safety　lithium　batteries.