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<p>Lithium–Sulfur (Li-S) batteries are considered promising next-generation energy storage systems owing to their exceptionally high theoretical specific capacity and energy density. However, their practical implementation is hindered by several critical challenges, including the low electrical conductivity of sulfur, dissolution of lithium polysulfides, severe shuttle effects, and safety issues associated with conventional electrolytes. In the present work, an integrated materials and cell engineering strategy is proposed to address these limitations through the development of high-performance sulfur–carbon composite cathodes, a bifunctional permselective membrane, and optimized electrolyte systems. Porous carbon scaffolds derived from carbon nanotubes (CNT), polyaniline (PANI), and biomass-derived bagasse carbon were employed as conductive sulfur hosts to enhance sulfur utilization and suppress polysulfide dissolution. Among the investigated cathodes, nitrogen-doped bagasse carbon–sulfur composites exhibited superior electrochemical performance with discharge capacities exceeding ~900&#xa0;mAh&#xa0;g<sup>−1</sup> after extended cycling, attributed to the synergistic effects of heteroatom doping, hierarchical porosity, and improved polysulfide adsorption. To further mitigate polysulfide migration, a trilayer permselective membrane consisting of LiAlO<sub>2</sub>/Celgard/activated carbon (AC) was developed. The LiAlO<sub>2</sub> ceramic layer provides a polar chemical barrier for polysulfide adsorption, while the activated carbon interlayer offers physical confinement and reutilization of dissolved polysulfides. The membrane significantly suppresses self-discharge and improves cycling stability, enabling discharge capacities of ~900–950&#xa0;mAh&#xa0;g<sup>−1</sup> after 50 cycles with coulombic efficiencies approaching 100%. In addition, electrolyte safety was improved through the incorporation of functional additives, where phosphorus and fluorine-containing compounds demonstrated enhanced flame-retardant behavior compared with conventional ether-based electrolytes. Finally, the optimized cathode–separator–electrolyte system was successfully translated from coin cells to a practical Li-S pouch cell delivering ~500&#xa0;mAh capacity with stable cycling performance. The combined results demonstrate that the synergistic integration of conductive carbon hosts, bifunctional permselective membranes, and safer electrolyte formulations provides an effective approach for high-performance and scalable lithium–sulfur batteries.</p>

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Integrated Development of Sulfur–Carbon Composite Cathodes and a Bifunctional Permselective Membrane for High-Performance Lithium–Sulfur Batteries

  • 期刊论文

  • 发表日期：

    2026年6月27日

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  • Alok Singh,
  • Savita Singh,
  • Arti Saxena,
  • Shailendra K. Singh

摘要

Lithium–Sulfur (Li-S) batteries are considered promising next-generation energy storage systems owing to their exceptionally high theoretical specific capacity and energy density. However, their practical implementation is hindered by several critical challenges, including the low electrical conductivity of sulfur, dissolution of lithium polysulfides, severe shuttle effects, and safety issues associated with conventional electrolytes. In the present work, an integrated materials and cell engineering strategy is proposed to address these limitations through the development of high-performance sulfur–carbon composite cathodes, a bifunctional permselective membrane, and optimized electrolyte systems. Porous carbon scaffolds derived from carbon nanotubes (CNT), polyaniline (PANI), and biomass-derived bagasse carbon were employed as conductive sulfur hosts to enhance sulfur utilization and suppress polysulfide dissolution. Among the investigated cathodes, nitrogen-doped bagasse carbon–sulfur composites exhibited superior electrochemical performance with discharge capacities exceeding ~900 mAh g−1 after extended cycling, attributed to the synergistic effects of heteroatom doping, hierarchical porosity, and improved polysulfide adsorption. To further mitigate polysulfide migration, a trilayer permselective membrane consisting of LiAlO2/Celgard/activated carbon (AC) was developed. The LiAlO2 ceramic layer provides a polar chemical barrier for polysulfide adsorption, while the activated carbon interlayer offers physical confinement and reutilization of dissolved polysulfides. The membrane significantly suppresses self-discharge and improves cycling stability, enabling discharge capacities of ~900–950 mAh g−1 after 50 cycles with coulombic efficiencies approaching 100%. In addition, electrolyte safety was improved through the incorporation of functional additives, where phosphorus and fluorine-containing compounds demonstrated enhanced flame-retardant behavior compared with conventional ether-based electrolytes. Finally, the optimized cathode–separator–electrolyte system was successfully translated from coin cells to a practical Li-S pouch cell delivering ~500 mAh capacity with stable cycling performance. The combined results demonstrate that the synergistic integration of conductive carbon hosts, bifunctional permselective membranes, and safer electrolyte formulations provides an effective approach for high-performance and scalable lithium–sulfur batteries.