The　rapid　development　of　new　energy　technologies　has　facilitated　the　widespread　adoption　of　electric　vehicles,　but　has　also　led　to　a　significant　increase　in　the　generation　of　spent　lithium-ion　batteries　(LIBs).　Extensive　research　has　been　conducted　on　the　recycling　of　spent　LIBs　with　most　studies　focusing　on　the　recovery　of　the　anode　and　cathode　materials,　electrolytes,　and　current　collectors.　Research　on　the　recycling　of　battery　separators　remains　limited.　Pyrolysis　technology　has　been　shown　to　enable　the　efficient　recovery　of　organic　components　and　has　already　been　applied　in　the　recycling　of　spent　LIB　separators.　However,　existing　studies　reveal　that　the　mechanisms　underlying　separator　pyrolysis　are　not　well　understood,　and　the　role　of　endogenous　metals　(Cu　and　Al　foil)　in　the　pyrolysis　process　remains　unclear.　Density　Functional　Theory　(DFT)　calculations　have　been　extensively　employed　in　mechanistic　investigations　of　organic　compound　pyrolysis　and　metal-catalyzed　reactions.　In　this　context,　the　commonly　used　polypropylene　(PP)　separator　was　selected　as　the　subject　of　this　study.　Various　thermal　analysis　devices　and　kinetic　methods　were　employed　to　investigate　the　pyrolysis　characteristics,　pyrolysis　kinetics,　distribution　of　pyrolysis　products,　and　the　influence　of　metal　foils　on　the　pyrolysis　process　of　PP　separators.　Through　DFT　calculations　and　wave　function　analysis,　the　pyrolysis　mechanism　of　PP　separators　and　the　catalytic　role　of　metal　foils　in　the　PP　pyrolysis　process　were　elucidated.　©　2025　Elsevier　Ltd