Solid-state synergy: Sulfur cathodes, engineered interfaces, and doping innovations for next-gen batteries

This review examined Sulfur-based Batteries that possess all-solid-state (ASS) as cutting-edge conservation of energy technologies that offer remarkable theoretical capacity (1675 mAh g⁻¹), enhanced safety, and cost-effectiveness. By employing solid electrolytes based on sulfide, as Li₆PS₅Cl and Li₇P₃S₁₁, ASSBs overcome challenges faced by traditional Li–S batteries, including polysulfide shuttling and flammability. However, interfacial instability, dendrite growth, and mechanical degradation remain key limitations. To address these, researchers have introduced doping strategies (e.g., N, Se, Te, Co, W, Cl, Ta) and engineered sulfur cathodes with carbon frameworks. Notable performances include N-doped carbon–sulfur cathodes with 1145.9 mAh g⁻¹ initial capacity contrast to 88.14 % of storage capacity 100 cycles later, and Se-doped cathodes with 473.8 mAh g⁻¹ and 99.4 % retention. Electrolyte enhancements exhibit conductivities of up to 6.4 mS/cm. Mechano-electrochemical stability is enhanced by utilising flexible polymers and cross-linked structures, thereby reducing stress and maintaining conductive pathways. These advances have enabled ASSBs to accomplish energy intensity up to 2600 Wh kg⁻¹ , rapid charging, and reliable operation at −40 °C, making them ideal for electric vehicles, aerospace, and grid storage. Ongoing efforts in interfacial design, AI-assisted material discovery, and scalable fabrication are essential for commercial realisation.