Shuttling　behavior　and　sluggish　redox　kinetics　of　lithium　polysulfides　(LiPSs)　are　fundamental　reasons　that　impede　the　practical　application　of　lithium-sulfur　batteries　(LSBs).　Herein,　a　novel　FeS2-embedded　N-doped　carbon　(FeS2-NC)　nanocage　is　reported　as　a　separator　coating　material　to　alleviate　these　problems.　It　is　also　for　the　first　time　that　FeS2　is　applied　to　the　separator　coating　of　LSBs.　The　yolk-pleat-shell　structure　of　FeS2-NC　was　synthesized　via　the　pyrolysis　of　iron　complexes　prepared　by　Schiff　base　condensation　and　subsequent　sulfurization　treatment.　The　large　internal　space　of　FeS2-NC　not　only　physically　confines　LiPSs　but　also　forms　a　highspeed　electron-ion　transport　network　in　cooperation　with　the　highly　polar　compound　FeS2,　providing　abundant　chemical　adsorption　and　catalytic　sites　for　fast　conversions　of　LiPSs.　Theoretical　calculation　further　confirms　that　FeS2　has　strong　adsorption　energy　for　both　Li2S6　and　Li2S8,　while　in-situ　Raman　analysis　also　reveals　the　interaction　between　FeS2　and　LiPSs.　In　addition,　coin　cells　with　the　light　functional　separator　(coating　loading:　0.2　mg　cm(-2))　have　a　ultrahigh　initial　capacity　of　1613.6　mAh　g(-1)　at　0.1C　and　a　satisfactory　cyclability　of　652.3　mAh　g(-1)　at　1C　over　600　cycles　with　an　attenuation　rate　of　0.049%　per　cycle.　Even　the　high-sulfur-loaded　(2.73　mg　cm(-2))　pouch　cell　release　a　lasting　high　areal　capacity　of　2.38　mAh　cm(-2)　at　0.4C.　These　results　demonstrate　that　FeS2-NC　has　the　efficient　capability　as　polysulfide　trapping-catalyzing　nanoreactor　for　LSBs　application.