Polymeric　materials　usually　present　substantial　hazards　to　human　health　and　the　environment　as　a　consequence　of　their　flammability　which　leads　to　the　emission　of　a　great　deal　of　heat　and　toxic　fumes.　To　address　this　issue,　it　is　imperative　to　urgently　enhance　the　flame　retardancy　of　polymer　materials.　This　study　focuses　on　the　synthesis　of　a　novel　gel-silica/polydopamine　double-layer　microencapsulated　cobalt　ions　(Co2+)　modified　ammonium　polyphosphate　(APP-Co@PDA@Si)　and　its　utilization　in　thermoplastic　polyurethane　(TPU)　composites.　The　resulting　TPU　composite,　containing　10.0　wt%　APP-Co@PDA@Si,　exhibited　excellent　flame-retardant　properties,　i.e.　achieving　a　limiting　oxygen　index　of　30.0　%　and　the　V-0　grade　in　the　UL-94　test.　Furthermore,　peak　heat　release　rate,　total　heat　release,　peak　smoke　production　rate,　and　total　smoke　release　of　the　TPU　composite　were　decreased　by　88.51　%,　66.06　%,　61.73　%,　and　74.01　%,　respectively,　in　comparison　to　those　of　pure　TPU.　The　enhanced　fire　safety　of　the　TPU　composite　was　attributed　to　the　synergistic　effect　among　Co2+　catalytic　carbonization,　the　free　radicals　capture　effect　of　APP,　and　the　flame-retardant　functions　of　PDA　and　silane.　This　innovative　strategy　proposed　in　this　work　holds　great　promise　for　improving　the　fire-resistance　of　TPU.　©　2024　Elsevier　Ltd