Lithium/sodium-sulfur　(Li-S/Na-S)　batteries　have　emerged　as　promising　next-generation　energy　storage　systems　due　to　their　high　theoretical　energy　density　and　cost-effectiveness.　However,　their　practical　implementation　is　hindered　by　the　polysulfide　shuttle　effect　and　sluggish　redox　kinetics　at　the　cathode-electrolyte　interface.　This　study　employs　first-principles　calculations　to　systematically　evaluate　the　BC2P　monolayer　as　a　novel　catalyst　for　Li-S　batteries.　The　unique　B-P-C　coordination　environment　of　BC2P　simultaneously　enables　the　thermodynamic　stability　and　efficient　charge　transfer.　Remarkably,　BC2P　demonstrates　strong　polysulfide　anchoring　capability,　effectively　suppressing　the　shuttle　effect.　Furthermore,　BC2P　significantly　reduces　the　energy　barrier　for　polysulfide　reduction　reactions　to　0.32　eV　and　0.45　eV　for　the　Li-S/Na-S　system,　confirming　its　catalytic　activity.　The　unique　B-P-C　coordination　environment　creates　active　sites　that　simultaneously　enhance　polysulfide　adsorption　and　conversion　kinetics.　Notably,　nonmetallic　single-atom　doping　transforms　BC2P　into　a　metallic　conductor,　further　strengthening　the　adsorption　and　reducing　the　reaction　barriers,　with　B-doped　BC2P　exhibiting　the　most　favorable　catalytic　activity　(energy　barrier　as　0.07　eV　and　0.23　eV　for　Li-S/Na-S　system).　These　findings　establish　BC2P　as　a　promising　cathode　material　that　addresses　both　the　shuttle　effect　and　kinetic　limitations　in　Li-S　batteries,　providing　new　insights　for　the　design　of　high-performance　sulfur　hosts.　©　2025　Elsevier　B.V.