This study presents a high-entropy alloy (HEA) nanocatalyst for lithium-sulfur (Li–S) batteries, which significantly enhances sulfur redox kinetics and suppresses the shuttle effect of lithium polysulfides (LiPSs). The HEA, composed of Co, Ni, Fe, Pd, and V, is synthesized via ultrafast Joule heating on carbon nanofibers (CNFs), resulting in nanoscale HEA particles with a disordered structure and high surface area. The HEA effectively adsorbs LiPSs, improving their conversion kinetics and reducing the loss of active sulfur. In situ Raman spectroscopy and density functional theory (DFT) calculations confirm the interaction between HEAs and LiPSs, which suppresses LiPS dissolution and the shuttle effect. The HEA-based Li–S batteries achieve a high specific capacity of 1364 mAh g⁻¹ at 0.1 C and maintain excellent cycling stability, with only a 0.054% capacity fade per cycle over 1000 cycles at 2 C. The pouch cell achieves a high specific capacity of 1192 mAh g⁻¹. The HEA catalysts demonstrate superior performance due to their synergistic effects in accelerating sulfur redox reactions, making them promising for improving Li–S battery performance. The study highlights the potential of HEA catalysis in enhancing the electrochemical conversion of sulfur species, offering a new strategy for high-performance Li–S batteries. The HEA catalysts also show excellent stability and electrochemical activity, making them suitable for use in lean-electrolyte systems. The results demonstrate the effectiveness of HEA catalysts in overcoming the challenges of Li–S batteries, including the shuttle effect and slow redox kinetics. The study provides insights into the design of high-entropy catalysts for energy storage applications.This study presents a high-entropy alloy (HEA) nanocatalyst for lithium-sulfur (Li–S) batteries, which significantly enhances sulfur redox kinetics and suppresses the shuttle effect of lithium polysulfides (LiPSs). The HEA, composed of Co, Ni, Fe, Pd, and V, is synthesized via ultrafast Joule heating on carbon nanofibers (CNFs), resulting in nanoscale HEA particles with a disordered structure and high surface area. The HEA effectively adsorbs LiPSs, improving their conversion kinetics and reducing the loss of active sulfur. In situ Raman spectroscopy and density functional theory (DFT) calculations confirm the interaction between HEAs and LiPSs, which suppresses LiPS dissolution and the shuttle effect. The HEA-based Li–S batteries achieve a high specific capacity of 1364 mAh g⁻¹ at 0.1 C and maintain excellent cycling stability, with only a 0.054% capacity fade per cycle over 1000 cycles at 2 C. The pouch cell achieves a high specific capacity of 1192 mAh g⁻¹. The HEA catalysts demonstrate superior performance due to their synergistic effects in accelerating sulfur redox reactions, making them promising for improving Li–S battery performance. The study highlights the potential of HEA catalysis in enhancing the electrochemical conversion of sulfur species, offering a new strategy for high-performance Li–S batteries. The HEA catalysts also show excellent stability and electrochemical activity, making them suitable for use in lean-electrolyte systems. The results demonstrate the effectiveness of HEA catalysts in overcoming the challenges of Li–S batteries, including the shuttle effect and slow redox kinetics. The study provides insights into the design of high-entropy catalysts for energy storage applications.