A MXene-derived heterostructured electrocatalyst, MoS₂@Mo₂C, was developed to enhance sulfur reduction kinetics in lithium-sulfur (Li-S) batteries. The catalyst was synthesized by partial sulfurization of Mo₂C MXene, introducing sulfur atoms to create an electron delocalization effect. Theoretical simulations and electrochemical characterization showed that the MoS₂@Mo₂C heterojunction promotes ion desolvation, increases free Li⁺ concentration, and accelerates Li⁺ transport, improving polysulfide conversion. The material also accelerates polysulfide oxidation and reduction through defects and vacancies, enhancing catalytic efficiency. The Li-S battery with the MoS₂@Mo₂C catalyst maintained a high capacity (664.7 mAh·g⁻¹) for 500 cycles at 1 C and excellent rate performance (567.6 mAh·g⁻¹ at 5 C). Under high loading conditions, it retained 775.6 mAh·g⁻¹ after 100 cycles. At low temperatures (0 °C), it retained 838.4 mAh·g⁻¹ for 70 cycles with a low decay rate (0.063%). These results indicate that delocalized electrons effectively accelerate lithium polysulfide conversion, improving Li-S battery performance. The catalyst was synthesized by acid etching of MAX-phase Mo₂Ga₂C to obtain Mo₂C MXene, followed by sulfurization to form MoS₂@Mo₂C heterojunction. The catalyst was used in KB-S cathodes and modified separators. The heterojunction exhibited a 3D structure with abundant interfaces, defects, and vacancies, confirmed by SEM, TEM, and EDS. XRD analysis confirmed the presence of MoS₂ and Mo₂C without impurities. The study demonstrates the effectiveness of electron delocalization in enhancing Li-S battery performance through improved sulfur reduction kinetics and catalytic efficiency.A MXene-derived heterostructured electrocatalyst, MoS₂@Mo₂C, was developed to enhance sulfur reduction kinetics in lithium-sulfur (Li-S) batteries. The catalyst was synthesized by partial sulfurization of Mo₂C MXene, introducing sulfur atoms to create an electron delocalization effect. Theoretical simulations and electrochemical characterization showed that the MoS₂@Mo₂C heterojunction promotes ion desolvation, increases free Li⁺ concentration, and accelerates Li⁺ transport, improving polysulfide conversion. The material also accelerates polysulfide oxidation and reduction through defects and vacancies, enhancing catalytic efficiency. The Li-S battery with the MoS₂@Mo₂C catalyst maintained a high capacity (664.7 mAh·g⁻¹) for 500 cycles at 1 C and excellent rate performance (567.6 mAh·g⁻¹ at 5 C). Under high loading conditions, it retained 775.6 mAh·g⁻¹ after 100 cycles. At low temperatures (0 °C), it retained 838.4 mAh·g⁻¹ for 70 cycles with a low decay rate (0.063%). These results indicate that delocalized electrons effectively accelerate lithium polysulfide conversion, improving Li-S battery performance. The catalyst was synthesized by acid etching of MAX-phase Mo₂Ga₂C to obtain Mo₂C MXene, followed by sulfurization to form MoS₂@Mo₂C heterojunction. The catalyst was used in KB-S cathodes and modified separators. The heterojunction exhibited a 3D structure with abundant interfaces, defects, and vacancies, confirmed by SEM, TEM, and EDS. XRD analysis confirmed the presence of MoS₂ and Mo₂C without impurities. The study demonstrates the effectiveness of electron delocalization in enhancing Li-S battery performance through improved sulfur reduction kinetics and catalytic efficiency.