Lithium-sulfur　(Li-S)　batteries　exhibit　superior　theoretical　capacity　and　energy　density　but　are　still　hindered　by　the　sluggish　redox　conversion　kinetic　of　lithium　polysulfides　arising　from　the　significant　desolvation　barrier,　especially　under　high　current　density　or　low-temperature　environments.　Herein,　a　two-dimensional　(2D)　porous　graphitic　phase　carbon　nitride/MXene　(CN-MX)　heterostructure　with　intrinsic　defects　was　designed　via　electrostatic　adherence　and　in-situ　thermal　polycondensation.　In　the　design,　the　defect-rich　CN　with　abundant　catalytic　activity　and　porous　structure　could　efficiently　facilitate　the　lithium　polysulfides　capture,　the　dissociation　of　solvated　lithium-ion　(Li+),　and　fast　Li+　diffusion.　Concurrently,　2D　MXene　nanosheets　with　high　electronic　conductivity　could　act　as　charge　transport　channels　and　provide　electrochemical　active　sites　for　sulfur　redox　reactions.　The　Li-S　cells　with　CN-MX　heterostructure　modified　separator　demonstrated　uncommon　rate　performance　(945　mAh/g　at　4.0　C)　and　satisfactory　areal　capacity　(5.5　mAh　cm−2　at　0.2　C).　Most　remarkably,　even　at　0　°C,　the　assembled　Li-S　batteries　performed　favorable　cycle　stability　(91.6%　capacity　retention　after　100　cycles　at　0.5　C)　and　outstanding　rate　performance　(695　mAh/g　at　2.0　C),　and　superior　high　loading　performance　(5.1　mAh　cm−2　at　0.1　C).　This　work　offers　exciting　new　insights　to　enable　Li-S　batteries　to　operate　in　extreme　environments.　©　2024　Elsevier　Inc.